AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON OCTOBER 24, 1997     
                                                     REGISTRATION NO. 333-34337
- -------------------------------------------------------------------------------
- -------------------------------------------------------------------------------
                      SECURITIES AND EXCHANGE COMMISSION
                            WASHINGTON, D.C. 20549
                                
                             AMENDMENT NO. 2     
                                      TO
                                   FORM S-4
                            REGISTRATION STATEMENT
                                     UNDER
                          THE SECURITIES ACT OF 1933

                          ANSAN PHARMACEUTICALS, INC.
            (EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)
 
          DELAWARE                       2836                  94-3171943
      (STATE OR OTHER        (PRIMARY STANDARD INDUSTRIAL   (I.R.S. EMPLOYER
     JURISDICTION OF          CLASSIFICATION CODE NUMBER)    IDENTIFICATION
      INCORPORATION OR                                           NUMBER)
        ORGANIZATION)
 
 SUITE 435, 400 OYSTER POINT BOULEVARD, SOUTH SAN FRANCISCO, CALIFORNIA 94080
                                (650) 635-0200
  (ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING AREA CODE, OF
                   REGISTRANT'S PRINCIPAL EXECUTIVE OFFICES)
 
                             VAUGHAN H.J. SHALSON
                     PRESIDENT AND CHIEF EXECUTIVE OFFICER
                          ANSAN PHARMACEUTICALS, INC.
                     SUITE 435, 400 OYSTER POINT BOULEVARD
                     SOUTH SAN FRANCISCO, CALIFORNIA 94080
                                (650) 635-0200
(NAME, ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING AREA CODE,
                             OF AGENT FOR SERVICE)
 
           WITH COPIES OF ALL ORDERS, NOTICES AND COMMUNICATIONS TO:
 
                               AUGUST J. MORETTI
                               RICHARD A. PEERS
                        HELLER EHRMAN WHITE & MCAULIFFE
                             525 UNIVERSITY AVENUE
                                  11TH FLOOR
                          PALO ALTO, CALIFORNIA 94301
                                (650) 324-7000
 
  APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC: As soon as
practicable after the Registration Statement becomes effective.

                               ----------------
 
  If any of the securities being registered on this Form are to be offered in
connection with the formation of a holding company and there is compliance
with General Instruction G, check the following box. [_]
 
                               ----------------
 
  THE REGISTRANT HEREBY AMENDS THIS REGISTRATION STATEMENT ON SUCH DATE OR
DATES AS MAY BE NECESSARY TO DELAY ITS EFFECTIVE DATE UNTIL THE REGISTRANT
SHALL FILE A FURTHER AMENDMENT WHICH SPECIFICALLY STATES THAT THIS
REGISTRATION STATEMENT SHALL THEREAFTER BECOME EFFECTIVE IN ACCORDANCE WITH
SECTION 8(a) OF THE SECURITIES ACT OF 1933 OR UNTIL THE REGISTRATION STATEMENT
SHALL BECOME EFFECTIVE ON SUCH DATE AS THE COMMISSION, ACTING PURSUANT TO SAID
SECTION 8(a), MAY DETERMINE.
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- -------------------------------------------------------------------------------

                          ANSAN PHARMACEUTICALS, INC.
                     SUITE 435, 400 OYSTER POINT BOULEVARD
                     SOUTH SAN FRANCISCO, CALIFORNIA 94080
                                (650) 635-0200
                                                             
Dear Stockholder:                                         October 24, 1997     
   
  A Special Meeting of Stockholders (the "Special Meeting") of ANSAN
PHARMACEUTICALS, INC. ("Ansan") will be held at Ansan's principal executive
offices, Suite 435, 400 Oyster Point Boulevard, South San Francisco,
California 94080, on November 24, 1997, at 10:00 a.m., local time.     
 
  At the Special Meeting, you will be asked to consider and vote on the
following proposals: (i) to approve the Agreement and Plan of Reorganization
and Merger (the "Merger Agreement") dated as of July 16, 1997 between Ansan
and Discovery Laboratories, Inc., a Delaware corporation ("Discovery"),
whereby Discovery shall be merged with and into Ansan (the "Merger"), (ii) to
approve an amendment to the Certificate of Incorporation of Ansan to (a)
convert and reconstitute the Common Stock, par value $0.001, of Ansan whereby
such number of shares of Common Stock between two and five, such number
consisting only of whole shares and tenths of shares, as shall be determined
by the Ansan Board of Directors, shall be converted and reconstituted into one
share of Ansan Common Stock in a reverse stock split of the Ansan Common
Stock, and (b) pay cash equal to the fair market value, as determined by the
Board of Directors, of any fractional shares resulting from such conversion
and reconstitution and (iii) to approve an amendment to the 1995 Ansan Stock
Option Plan increasing the number of shares of Ansan Common Stock available
for issuance thereunder by 937,400 to a total of 1,187,400 shares of Ansan
Common Stock.
 
  Based on the provisions of the Merger Agreement, each outstanding share of
Common Stock, $0.001 par value, of Discovery will be converted into 1.167471
(the "Exchange Ratio") shares of Ansan Common Stock and each outstanding share
of Series A Convertible Preferred Stock, $0.001 par value, of Discovery, will
be converted into one share of Series B Convertible Preferred Stock, $0.001
par value, of Ansan. Further, the Merger Agreement provides that Ansan will
assume all of Discovery's obligations with respect to any outstanding
Discovery options and warrants. The Exchange Ratio was determined without
adjustment for the reverse stock split proposal outlined above. This
adjustment may be effected prior to the Merger if such proposal is approved by
the Ansan stockholders and such reverse stock split is consummated prior to
the Merger.
 
  After careful consideration, your Board of Directors has approved the Merger
Agreement described in the attached material and the transactions contemplated
thereby and has concluded that they are fair to and in the best interests of
Ansan and its stockholders. Your Board of Directors recommends a vote in favor
of the Merger.
 
  In the material accompanying this letter, you will find a Notice of Special
Meeting of Stockholders, a Prospectus/Proxy Statement relating to the actions
to be taken by Ansan stockholders at the Special Meeting and a proxy card. The
Prospectus/Proxy Statement more fully describes the proposed Merger and
includes information about Ansan and Discovery and about certain other matters
for consideration at the Special Meeting. All stockholders are cordially
invited to attend the Special Meeting in person. However, whether or not you
plan to attend the Special Meeting, please complete, sign, date and return
your proxy in the enclosed envelope. If you attend the Special Meeting, you
may vote in person if you wish, even though you have previously returned your
proxy. It is important that your shares be represented and voted at the
Special Meeting.
 
                                          Sincerely,
 
                                          Vaughan H. J. Shalson
                                          President and Chief Executive
                                           Officer

                          ANSAN PHARMACEUTICALS, INC.
                     SUITE 435, 400 OYSTER POINT BOULEVARD
                     SOUTH SAN FRANCISCO, CALIFORNIA 94080
                                (650) 635-0200
 
                   NOTICE OF SPECIAL MEETING OF STOCKHOLDERS
 
To the Stockholders of ANSAN PHARMACEUTICALS, INC.:
   
  A Special Meeting of Stockholders of ANSAN PHARMACEUTICALS, INC., a Delaware
corporation ("Ansan"), will be held at 10:00 a.m. on November 24, 1997 (the
"Special Meeting") at the principal executive offices of Ansan, Suite 435, 400
Oyster Point Boulevard, South San Francisco, California 94080, for the
following purposes:     
 
    1. To approve the Agreement and Plan of Reorganization and Merger (the
  "Merger Agreement") dated as of July 16, 1997 between Ansan and Discovery
  Laboratories, Inc., a Delaware corporation ("Discovery"), whereby Discovery
  shall be merged with and into Ansan and each share of Common Stock, par
  value $0.001, of Discovery will be converted into and exchanged for the
  right to receive 1.167471 shares of Common Stock, par value $0.001, of
  Ansan (the "Ansan Common Stock") and each share of Series A Convertible
  Preferred Stock, par value $0.001, of Discovery will be converted with and
  exchanged into the right to receive one share of Series B Convertible
  Preferred Stock, par value $0.001, of Ansan. All outstanding warrants and
  options of Discovery will be assumed by Ansan and, following such
  assumption, Ansan will issue shares of Ansan capital stock upon exercise of
  such warrants and options.
 
    2. To approve an amendment to the Certificate of Incorporation of Ansan
  to (a) convert and reconstitute the Ansan Common Stock whereby such number
  of shares of Ansan Common Stock between two and five, such number
  consisting only of whole shares and tenths of shares, as shall be
  determined by the Ansan Board of Directors shall be converted and
  reconstituted into one share of Ansan Common Stock in a reverse stock split
  of Ansan Common Stock and (b) pay cash equal to the fair market value, as
  determined by the Board of Directors, of any fractional shares resulting
  from such conversion and reconstitution.
 
    3. To approve an amendment to the Ansan 1995 Stock Option Plan increasing
  the number of share of Ansan Common Stock available for issuance thereunder
  by 937,400 to a total of 1,187,400 shares of Ansan Common Stock.
 
  The foregoing items of business are more fully described in the
Prospectus/Proxy Statement accompanying this Notice.
   
  Only stockholders of record of Ansan Common Stock and Ansan Series A
Convertible Preferred Stock at the close of business on October 22, 1997 are
entitled to notice of and to vote at the Special Meeting or any adjournment
thereof. Approval of the Merger and the amendment to the Certificate of
Incorporation will each require the affirmative vote of the holders of a
majority of the shares of Ansan Common Stock and Ansan Series A Convertible
Preferred Stock outstanding on the record date. Approval of the amendment to
the Ansan 1995 Stock Option Plan will require the affirmative vote of the
majority of the shares of Ansan Common Stock and Ansan Series A Convertible
Preferred Stock represented and voting at the Special Meeting.     
 
South San Francisco, California
   
October 24, 1997                          BY ORDER OF THE BOARD OF DIRECTORS
 
                                          James Ahlers
                                          Secretary
 
TO ASSURE THAT YOUR SHARES ARE REPRESENTED AT THE MEETING, YOU ARE URGED TO
FILL IN, DATE AND SIGN THE ENCLOSED PROXY AND MAIL IT PROMPTLY IN THE POSTAGE-
PAID ENVELOPE PROVIDED, WHETHER OR NOT YOU PLAN TO ATTEND THE MEETING IN
PERSON. YOUR PROXY CAN BE WITHDRAWN BY YOU AT ANY TIME BEFORE IT IS VOTED.

                         DISCOVERY LABORATORIES, INC.
                        509 MADISON AVENUE, 14TH FLOOR
                           NEW YORK, NEW YORK 10022
                                (212) 223-9504
                                                             
                                                          October 27, 1997     
 
Dear Stockholder:
   
  Enclosed for your consideration on behalf of the Board of Directors of
Discovery Laboratories, Inc. ("Discovery") are (i) a written consent (the
"Written Consent") to the proposed merger (the "Merger") of Discovery with and
into Ansan Pharmaceuticals, Inc. ("Ansan") pursuant to an Agreement and Plan
of Reorganization and Merger (the "Merger Agreement") dated as of July 16,
1997 between Ansan and Discovery, and (ii) a prospectus describing the Merger
and the Merger Agreement and setting forth certain information with respect to
Ansan and Discovery in connection therewith. If approved by the stockholders
of Ansan and of Discovery, the Merger is expected to be consummated on or
about November 24, 1997.     
 
  Based on the provisions of the Merger Agreement, each outstanding share of
Common Stock, $0.001 par value, of Discovery will be converted into 1.167471
(the "Exchange Ratio") shares of the Common Stock, $0.001 par value, of Ansan
(the "Ansan Common Stock") and each outstanding share of Series A Convertible
Preferred Stock, $0.001 par value, of Discovery will be converted into one
share of Series B Convertible Preferred Stock, $0.001 par value, of Ansan (the
"Ansan Series B Preferred Stock"). Each share of Ansan Series B Preferred
Stock will initially be convertible into 4.669884 shares of Ansan Common Stock
and will otherwise have the same rights, preferences and privileges as the
Discovery Series A Preferred Stock for which it is being exchanged. Further,
the Merger Agreement provides that Ansan will assume all of Discovery's
obligations with respect to any outstanding Discovery options and warrants.
The Exchange Ratio was determined without adjustment for a reverse stock split
of the Ansan Common Stock proposed to be effected. Such adjustment may be
effected prior to the Merger in the event such proposal is approved by Ansan's
stockholders and such reverse stock split is consummated prior to the Merger.
 
  After careful consideration, your Board of Directors has approved the Merger
Agreement and the transactions contemplated thereby and has concluded that
they are in the best interests of Discovery. Your Board of Directors
recommends a vote in favor of the Merger.
   
  It is a condition to the Merger that the holders of 85% or more of
Discovery's outstanding equity securities execute agreements (the "Lock-Up
Agreements") to refrain from selling or otherwise disposing of such equity
securities (or, in the case of investors in Discovery's 1996 private
placement, portions of such securities, according to a schedule specified in
the Lock-Up Agreements to be executed by such investors) until the first
anniversary of the Merger. Please execute the Written Consent and the enclosed
Lock-Up Agreement and return them to Discovery at 509 Madison Avenue, 14th
Floor, New York, New York 10022, Attention: Evan Myrianthopoulos.     
 
                                          Sincerely,
 
                                          James S. Kuo, M.D.
                                          President and Chief Executive
                                           Officer

                          ANSAN PHARMACEUTICALS, INC.
 
                          PROSPECTUS/PROXY STATEMENT
   
  ANSAN PHARMACEUTICALS, INC., a Delaware corporation ("Ansan"), has filed a
Registration Statement on Form S-4 (the "Registration Statement") with the
Securities and Exchange Commission (the "Commission") pursuant to the
Securities Act of 1933, as amended (the "Securities Act"), for the
registration of 8,653,122 shares of its authorized but unissued Common Stock,
$0.001 par value (the "Ansan Common Stock"), and 2,200,256 shares of its
authorized but unissued Series B Convertible Preferred Stock, $0.001 par value
(the "Ansan Series B Preferred Stock") to be issued in connection with the
merger (the "Merger") of Discovery Laboratories, Inc., a Delaware corporation
("Discovery"), with and into Ansan. As a result of the Merger, each
outstanding share of Common Stock, $0.001 par value, of Discovery (the
"Discovery Common Stock") will be converted into 1.167471 shares of Ansan
Common Stock (the "Common Exchange Ratio") and each outstanding share of
Series A Convertible Preferred Stock, par value $0.001, of Discovery (the
"Discovery Series A Preferred Stock" and together with the Discovery Common
Stock, the "Discovery Stock") will be converted into one share of Ansan Series
B Preferred Stock (the "Preferred Exchange Ratio"). Each share of Ansan Series
B Preferred Stock will be convertible into 4.669884 shares of Ansan Common
Stock (the "Series B Conversion Ratio"), subject to adjustment under certain
circumstances. In connection with the Merger, Ansan will also assume each
outstanding option and each outstanding warrant to purchase Discovery Stock
based on the Common Exchange Ratio or the Preferred Exchange Ratio. See "Terms
of the Merger--Manner and Basis of Converting Shares." Ansan may effect a
reverse stock split (the "Reverse Stock Split") of the Ansan Common Stock
prior to the Merger (see "Proposal 2--Ansan Certificate Amendment"). The
Common Exchange Ratio and the Series B Conversion Ratio shall be adjusted
proportionately for the Reverse Stock Split if the Reverse Stock Split is
effected prior to the Merger. See "Terms of the Merger--Conditions to the
Merger." If approved by Ansan and Discovery stockholders, the Merger is
expected to be consummated as soon as practicable after the special meeting of
stockholders of Ansan to be held on November 24, 1997 (the "Ansan Special
Meeting") and the date of receipt of the written consent of holders of
Discovery Stock representing a majority of the voting power of such stock
pursuant to Section 228 of the General Corporation Law of the State of
Delaware (the "Discovery Written Consent").     
 
  Stockholders of Discovery or Ansan who object to the Merger may, under
certain circumstances and by following prescribed statutory procedures,
exercise appraisal rights to receive cash for their shares. See "Terms of the
Merger--Appraisal Rights."
 
  This Prospectus/Proxy Statement constitutes: (a) the Proxy Statement of
Ansan relating to the solicitation of proxies by the Board of Directors of
Ansan for use at the Ansan Special Meeting and (b) the Prospectus of Ansan for
the issuance of Ansan Stock pursuant to the Merger filed as part of the
Registration Statement. This Prospectus/Proxy Statement is also being
distributed to holders of Discovery Stock in connection with the solicitation
of the Discovery Written Consent. All information herein with respect to Ansan
has been furnished by Ansan, and all information herein with respect to
Discovery has been furnished by Discovery.
 
                               ----------------
 
  THE MERGER INVOLVES CERTAIN RISKS TO ANSAN AND DISCOVERY STOCKHOLDERS. SEE
"RISK FACTORS" BEGINNING ON PAGE 12.
 
                               ----------------
 
  THE SECURITIES OF ANSAN TO BE ISSUED  IN THE MERGER HAVE NOT BEEN APPROVED
    OR DISAPPROVED BY THE  SECURITIES AND EXCHANGE  COMMISSION NOR HAS THE
      COMMISSION  PASSED   UPON  THE   ACCURACY  OR  ADEQUACY   OF  THIS
        PROSPECTUS/PROXY STATEMENT. ANY REPRESENTATION TO THE CONTRARY
                            IS A CRIMINAL OFFENSE.
 
                               ----------------
        
     The date of this Prospectus/Proxy Statement is October 23, 1997     

                             AVAILABLE INFORMATION
 
  Ansan has filed with the Commission a Registration Statement under the
Securities Act on Form S-4 (together with all amendments and exhibits thereto)
with respect to the Ansan Common Stock and Ansan Series B Preferred Stock
offered hereby. This Prospectus/Proxy Statement does not contain all of the
information set forth in the Registration Statement and the exhibits and
schedules thereto, certain parts of which have been omitted in accordance with
the rules and regulations of the Commission. For such information, reference
is made to the Registration Statement and the exhibits and schedules thereto.
In addition, Ansan is subject to the information requirements of the
Securities Exchange Act of 1934, as amended (the "Exchange Act"), and in
accordance therewith is required to file periodic reports, proxy statements
and other information with the Commission. Copies of such materials may be
obtained from the Commission at prescribed rates by addressing written
requests for such copies to the Public Reference Section of the Commission,
450 Fifth Street, N.W., Washington, D.C. 20549. The Registration Statement and
such reports, proxy statements and other information can also be inspected and
copied at the Commission's public reference facilities referred to above and
at the Commission's Regional Offices at 500 West Madison Street, Suite 1400,
Chicago, Illinois 60621-2511, and World Trade Center, Suite 1300, New York,
New York 10048. Electronic copies of all such reports are also available on
the World Wide Web at http://www.sec.gov/edgarhp.htm. In addition, the Ansan
Common Stock is listed and traded on the National Association of Securities
Dealers, Inc. ("NASD") SmallCap Market ("Nasdaq"), and such reports, proxy
statements and other information concerning Ansan may also be inspected at the
offices of the National Association of Securities Dealers, Inc., 1755 K
Street, N.W., Washington, D.C. 20006.
 
  Discovery is not subject to the reporting requirements of the Exchange Act.
 
                               ---------------
 
                                  TRADEMARKS
 
  Pivanex(TM) and Novaheme(TM) are trademarks of Ansan. SuperVent(TM) is a
trademark of Discovery. Surfaxin(TM) is a trademark of Acute Therapeutics,
Inc., a Delaware corporation and a majority-owned subsidiary of Discovery.
 
                          FORWARD-LOOKING STATEMENTS
 
  Other than statements of historical fact, statements made in this
Prospectus/Proxy Statement, including statements as to the benefits expected
to result from the Merger and as to future operating results and financial
performance and the analyses performed by the financial advisors to Ansan and
Discovery are forward-looking statements within the meaning of Section 27A of
the Securities Act and Section 21E of the Exchange Act. Actual results could
differ materially from those anticipated in such forward-looking statements as
a result of certain factors, including those set forth in "Risk Factors"
below, which stockholders should carefully review. See "Forward-Looking
Statements."
 
  NO PERSON IS AUTHORIZED TO GIVE ANY INFORMATION OR TO MAKE ANY
REPRESENTATION OTHER THAN AS CONTAINED HEREIN IN CONNECTION WITH THESE MATTERS
AND, IF GIVEN OR MADE, SUCH INFORMATION OR REPRESENTATION MUST NOT BE RELIED
UPON AS HAVING BEEN AUTHORIZED BY ANSAN, DISCOVERY OR ANY OTHER PERSON.
NEITHER THE DELIVERY HEREOF NOR ANY DISTRIBUTION OF SECURITIES MADE HEREUNDER
SHALL, UNDER ANY CIRCUMSTANCES, CREATE AN IMPLICATION THAT THERE HAS BEEN NO
CHANGE IN THE FACTS HEREIN SET FORTH SINCE THE DATE HEREOF. THIS
PROSPECTUS/PROXY STATEMENT DOES NOT CONSTITUTE AN OFFER TO SELL OR A
SOLICITATION OF AN OFFER TO BUY THE SECURITIES OFFERED BY THIS
PROSPECTUS/PROXY STATEMENT OR A SOLICITATION OF A PROXY IN ANY JURISDICTION
WHERE, OR TO ANY PERSON TO WHOM, IT IS UNLAWFUL TO MAKE SUCH AN OFFER OR
SOLICITATION.
 
  ALL INFORMATION CONTAINED IN THIS PROSPECTUS/PROXY STATEMENT REGARDING ANSAN
HAS BEEN PROVIDED BY ANSAN AND ALL INFORMATION CONTAINED IN THIS
PROSPECTUS/PROXY STATEMENT REGARDING DISCOVERY HAS BEEN PROVIDED BY DISCOVERY.

                               TABLE OF CONTENTS

                                                                           PAGE
                                                                           ----
                                                                        
Summary...................................................................   1
  The Companies...........................................................   1
  Ansan...................................................................   1
  Discovery...............................................................   1
  Meeting of Stockholders of Ansan and Written Consent of Stockholders of
   Discovery..............................................................   1
  Time, Date, Place and Purpose...........................................   1
  Special Meeting of Stockholders of Ansan................................   2
  Written Consent of the Stockholders of Discovery........................   3
  Risk Factors............................................................   4
  Opinions of Financial Advisors..........................................   4
  Income Tax Treatment....................................................   5
  Accounting Treatment....................................................   5
  The Merger..............................................................   5
  Effect of the Merger....................................................   5
  Effective Time of the Merger............................................   5
  Terms of the Merger.....................................................   5
  Exchange Ratios.........................................................   6
  The Board of Directors and Management of the Combined Company Following
   the Merger.............................................................   6
  Conditions to the Merger; Termination...................................   7
  Governmental and Regulatory Approvals...................................   7
  Voting Agreements.......................................................   7
  Restrictions on Resale..................................................   7
  Appraisal Rights........................................................   7
  Recent Events...........................................................   7
  Price Range of Ansan Common Stock.......................................   8
  Selected Historical And Pro Forma Financial Information.................   9
Forward Looking Statements................................................  13
Risk Factors..............................................................  13
Voting and Proxies........................................................  31
  Date, Time and Place of Special Ansan Meeting...........................  31
  Record Date and Outstanding Shares......................................  31
  Voting of Proxies.......................................................  31
  Vote Required...........................................................  31
  Solicitation of Proxies and Expenses....................................  32
The Merger and Related Transactions.......................................  32
  Background to the Merger................................................  32
  Interests of Certain Persons............................................  33
  Joint Reasons for the Merger............................................  34
  Ansan's Reasons for the Merger..........................................  34
  Discovery's Reasons for the Merger......................................  36
Material Contacts and Board Deliberations.................................  38
Financial Advisors........................................................  40
  Ansan...................................................................  40
  Discovery...............................................................  42
Terms of the Merger.......................................................  46
  Effective Time of the Merger............................................  46

                                       i

                                    SUMMARY
 
  The following is a brief summary of certain information contained elsewhere
in this Prospectus/Proxy Statement. This summary does not contain a complete
statement of all material features of the merger proposal to be voted on and is
qualified in its entirety by the more detailed information appearing elsewhere
in this Prospectus/Proxy Statement and in the Annexes hereto.
 
                                 THE COMPANIES
 
ANSAN
 
  Ansan Pharmaceuticals, Inc., a Delaware corporation ("Ansan"), is a
development stage pharmaceutical company engaged in the acquisition and further
development of drugs intended to treat serious medical conditions including
pancreatitis, cancer and cancer-related conditions, blood disorders and other
life-threatening diseases for which therapies are not yet available or current
therapies are not highly efficacious. Ansan in-licenses drug candidates that
have progressed beyond the initial discovery stage of development. Such
potential products have already undergone preclinical toxicity testing and have
demonstrated relevant biological activity in animal experiments. Ansan believes
that acquiring products that have already met or surpassed these preliminary
development hurdles can reduce product development times and increase the
probability of ultimate commercialization compared to untested drug candidates
emerging from initial discovery efforts.
   
  Ansan's principal executive offices are located at Suite 435, 400 Oyster
Point Boulevard, South San Francisco, California 94080 and its telephone number
is (650) 635-0200 (facsimile number (650) 635-0201). Ansan was originally
incorporated in Delaware in 1992 as Ansan, Inc. This name was changed to the
present name in 1996. Upon consummation of the Merger, Ansan's name will be
changed to Discovery Laboratories, Inc. See "Information Concerning Ansan."
    
DISCOVERY
 
  Discovery Laboratories, Inc., a Delaware corporation ("Discovery"), is a
development stage pharmaceutical company that is focused on acquiring,
developing and commercializing proprietary, investigational drugs that have
previously been tested in humans or animals. Discovery's strategy is to conduct
preclinical and clinical studies on investigational drugs licensed from third
parties, either alone or in collaboration with corporate partners. Discovery
currently has drug products under development intended to treat cystic
fibrosis, respiratory distress syndromes and postmenopausal osteoporosis.
 
  Discovery's principal executive offices are located at 509 Madison Avenue,
14th Floor, New York, New York 10022 and its telephone number is (212) 223-9504
(facsimile number (212) 688-7978). Discovery's internet address is
www.discoverylabs.com. See "Information Concerning Discovery."
 
    MEETING OF STOCKHOLDERS OF ANSAN AND WRITTEN CONSENT OF STOCKHOLDERS OF
                                   DISCOVERY
 
TIME, DATE, PLACE AND PURPOSE
   
  A Special Meeting of Stockholders of Ansan (the "Ansan Special Meeting") will
be held on November 24, 1997 at 10:00 a.m., local time, at Ansan's principal
executive offices, Suite 435, 400 Oyster Point Boulevard, South San Francisco,
California 94080.     
   
  On or about October 27, 1997 Discovery will solicit the written consent to
the transactions described herein (the "Discovery Written Consent") of its
stockholders of record on October 22, 1997 pursuant to Section 228 of the
General Corporation Law of the State of Delaware (the "DGCL").     
 
                                       1

 
  At the Ansan Special Meeting, Ansan stockholders will be asked to consider
and vote on the following proposals: (i) to approve the Agreement and Plan of
Reorganization and Merger (the "Merger Agreement") dated as of July 16, 1997
between Ansan and Discovery whereby Discovery shall be merged (the "Merger")
with and into Ansan ( the "Merger Proposal"), (ii) to approve an amendment to
the Certificate of Incorporation of Ansan (the "Ansan Certificate Amendment")
to (a) convert and reconstitute the Common Stock, $0.001 par value, of Ansan
(the "Ansan Common Stock") whereby such number of shares of Ansan Common Stock
between two and five, such number consisting only of whole shares and tenths of
shares, as shall be determined by the Ansan Board of Directors shall be
converted and reconstituted into one share of Ansan Common Stock in a reverse
stock split of Ansan Common Stock and (b) pay cash equal to the fair market
value, as determined by the Board of Directors, of any fractional share
resulting from such conversion and reconstitution (the "Reverse Stock Split"),
and (iii) to approve an amendment to the Ansan Stock Option Plan increasing the
number of shares of Ansan Common Stock available for issuance thereunder by
937,400 to a total of 1,187,400 shares of Ansan Common Stock (the "Ansan Stock
Plan Proposal").
 
  Pursuant to the Discovery Written Consent, Discovery stockholders will be
asked to consent to the Merger Proposal.
 
  See "The Merger and Related Transactions."
 
SPECIAL MEETING OF STOCKHOLDERS OF ANSAN
 
 Record Date, Proxies and Vote Required
   
  Only Ansan stockholders of record at the close of business on October 22,
1997 (the "Ansan Record Date") are entitled to notice of and to vote at the
Ansan Special Meeting. Each holder of Ansan Common Stock is entitled to one
vote for each share of Ansan Common Stock, and each holder of Ansan Series A
Convertible Preferred Stock, $0.001 par value (the "Ansan Series A Preferred
Stock") (the Ansan Common Stock and the Ansan Series A Preferred Stock are
collectively called the "Ansan Stock") is entitled to such number of votes for
each share of Ansan Series A Preferred Stock as is equal to the number of
shares of Ansan Common Stock into which such share of Ansan Series A Preferred
Stock could be converted. The Ansan Common Stock and the Ansan Series A
Preferred Stock shall vote together as a single class on all matters proposed
at the Ansan Special Meeting.     
 
  The affirmative vote of a majority of the shares of Ansan Stock issued and
outstanding, on an as-converted basis, as of the Ansan Record Date is required
to approve the Merger Proposal and the Ansan Certificate Amendment. Pursuant to
the DGCL, the affirmative vote of a majority of such shares present in person
or by proxy and entitled to vote is required to approve the amendment to the
Ansan Stock Option Plan.
 
  The presence, in person or by properly executed proxy, of the holders of a
majority of the outstanding shares of Ansan Stock, on an as-converted basis,
entitled to vote at the Ansan Special Meeting shall constitute a quorum.
Abstentions and broker non-votes will be included for purposes of determining
whether a quorum of shares is present at the Ansan Special Meeting. Abstentions
and broker non-votes will be treated as votes against the proposals. A broker
non-vote occurs when a nominee holding shares for a beneficial owner does not
vote on a particular proposal because the nominee does not have discretionary
voting power with respect to that item and has not received instructions from
the beneficial owner. In the amendment to the Ansan Stock Option Plan,
requiring approval by a majority of the total of the shares of Ansan Stock, on
an as-converted basis, present in person or by proxy and entitled to vote,
abstentions will be counted in the tabulation of voting results and will be
treated as votes against the proposal. Broker non-votes will not be treated as
"entitled to vote" and will have no effect on the voting result. It is not
expected that any matters other than those set forth above will be brought
before the Ansan Special Meeting. However, if other matters are properly
presented, the persons named in such proxy will have authority to vote in
accordance with their judgment on any such matters, including without
limitation, a proposal to adjourn the Ansan Special Meeting. If a proxy is
returned which specifies a vote against
 
                                       2

the Merger Proposal, such discretionary authority will not be used to adjourn
the Ansan Special Meeting in order to solicit additional votes in favor of the
Merger Proposal. See "Voting and Proxies".
 
  As of August 31, 1997, Titan Pharmaceuticals, Inc. ("Titan") owned an
aggregate of 1,212,654 shares of Ansan Common Stock representing approximately
32% of the issued and outstanding shares of Ansan Stock on an as-converted
basis, and Discovery owned an aggregate of 13,000 shares of Ansan Series A
Preferred Stock representing approximately 25% of the issued and outstanding
shares of Ansan Stock on an as-converted basis. As of August 31, 1997, officers
and directors owned options to purchase 270,810 shares of Ansan Common Stock
and no shares of Ansan Series A Preferred Stock. Titan has executed a voting
agreement (the "Titan Voting Agreement") which grants a proxy to
representatives of Discovery to vote in favor of the Merger Proposal and the
other matters to be presented at the Ansan Special Meeting. As of the Ansan
Record Date, there were approximately 600 beneficial owners and 12 stockholders
of record of Ansan Stock. As of such date, there were 2,851,954 shares of Ansan
Common Stock outstanding, each of which shares will be entitled to one vote on
each matter to be acted upon at the Ansan Special Meeting and 13,000 shares of
Ansan Series A Preferred Stock outstanding, each of which shares will be
entitled to approximately 71.4 votes on each matter to be acted upon at the
Ansan Special Meeting. As of the Ansan Record Date, Discovery was the only
stockholder of record of Ansan Series A Preferred Stock. See "Voting and
Proxies--Vote Required," and "Principal Stockholders."
 
 Recommendations of the Ansan Board
 
  The Ansan Board has approved the Merger Proposal and has determined that the
Merger is fair to and in the best interests of Ansan and its stockholders.
After careful consideration, the Ansan Board recommends a vote in favor of (i)
the Merger Proposal, (ii) the Ansan Certificate Amendment, and (iii) the Ansan
Stock Option Plan Proposal. Stockholders should read this Prospectus/Proxy
Statement (and the Annexes hereto) carefully before voting. See "The Merger and
Related Transactions--Joint Reasons for the Merger," "--Ansan's Reasons for the
Merger" and "--Material Contacts and Board Deliberations."
 
WRITTEN CONSENT OF THE STOCKHOLDERS OF DISCOVERY
 
 Record Date and Consent Required
   
  Only stockholders of Discovery at the close of business on October 22, 1997
(the "Discovery Record Date") are entitled to act by written consent pursuant
to the Discovery Written Consent. Each holder of the Common Stock, $0.001 par
value, of Discovery (the "Discovery Common Stock") is entitled to one vote for
each share of Discovery Common Stock on matters presented to the stockholders
of Discovery, and each holder of the Series A Convertible Preferred Stock,
$0.001 par value, of Discovery (the "Discovery Series A Preferred Stock") (the
Discovery Common Stock and the Discovery Series A Preferred Stock are
collectively called the "Discovery Stock") is entitled to such number of votes
as is equal to the number of shares of Discovery Common Stock into which such
Discovery Series A Preferred Stock could be converted. As of the Discovery
Record Date, each share of Discovery Series A Preferred Stock could be
converted into four shares of Discovery Common Stock.     
 
  Approval and adoption of the Merger Proposal requires the affirmative vote of
the majority of the votes of the outstanding shares of Discovery Stock, on an
as-converted basis, entitled to vote thereon. Pursuant to Section 228 of the
DGCL, such approval and adoption will be solicited pursuant to the Discovery
Written Consent. Since approval and adoption of the Merger Proposal requires
approval of a majority of the shares of Discovery Stock, on an as-converted
basis, issued and outstanding as of the Discovery Record Date, shares as to
which no written consent is received will be treated as votes against the
Merger Proposal.
 
  Certain stockholders of Discovery, who in the aggregate owned approximately
23.2% of the outstanding shares of Discovery Stock, on an as-converted basis,
as of the Discovery Record Date, have entered into Voting Agreements (the
"Discovery Voting Agreements") with Ansan. Pursuant to the Discovery Voting
Agreements, the foregoing persons have agreed to vote their shares in favor of
the adoption of the Merger Proposal and have granted irrevocable proxies to
Ansan to vote such persons' Discovery Common Stock in favor of the Merger.
 
                                       3

 
  As of August 31, 1997, officers and directors of Discovery beneficially owned
an aggregate of 1,018,850 outstanding shares of Discovery Common Stock
representing approximately 6.1% of the issued and outstanding shares of
Discovery Stock. As of the Discovery Record Date, there were approximately 255
stockholders of record of Discovery Common Stock and 6,747,256 shares of
Discovery Common Stock and 2,200,256 shares of Discovery Series A Preferred
Stock outstanding.
 
 Recommendation of the Discovery Board
 
  The Discovery Board has approved the Merger Proposal and has determined that
the Merger is fair to and in the best interests of Discovery. After careful
consideration, the Discovery Board recommends a vote in favor of the Merger
Proposal. Stockholders should read this Prospectus/Proxy Statement (including
the Annexes hereto) carefully prior to voting. See "The Merger and Related
Transactions--Joint Reasons for the Merger." "--Discovery's Reasons for the
Merger," and "--Material Contacts and Board Deliberations."
 
RISK FACTORS
 
  Stockholders of Ansan and Discovery should carefully evaluate the matters set
forth under "Risk Factors" beginning on page 13 below.
 
OPINIONS OF FINANCIAL ADVISORS
 
 Ansan
 
  Dakin Securities Corporation ("Dakin Securities") has delivered to the Ansan
Board a written opinion dated July 16, 1997, to the effect that, as of the date
of such opinion and based upon and subject to certain matters stated therein,
the terms of the Merger were fair from a financial point of view to the holders
of Ansan Stock. The full text of the written opinion of Dakin Securities, which
sets forth assumptions made, matters considered and limitations on the review
undertaken, is attached hereto as Annex A to this Prospectus/Proxy Statement
and should be read carefully in its entirety. Dakin Securities' opinion relates
only to the fairness of the Merger from the financial point of view to holders
of Ansan Stock and does not constitute a recommendation to any stockholder as
to how such stockholder should vote at the Ansan Special Meeting. See
"Financial Advisors--Ansan" and Annex A attached hereto.
 
 Discovery
 
  Sands Brothers & Co., Ltd. ("Sands Brothers") has delivered to the Discovery
Board a written opinion dated August 13, 1997, to the effect that, as of the
date of such opinion and based upon and subject to certain matters stated
therein, the Exchange Ratios pursuant to the Merger Agreement were fair from a
financial point of view to the holders of Discovery Stock. The full text of the
written opinion of Sands Brothers, which sets forth assumptions made, matters
considered and limitations on the review undertaken, is attached hereto as
Annex B to this Prospectus/Proxy Statement, and should be read carefully in its
entirety. Sands Brothers opinion relates only to the fairness of the Exchange
Ratios (as hereinafter defined) pursuant to the Merger Agreement from the
financial point of view to holders of Discovery Stock and does not constitute a
recommendation to any stockholder as to whether such stockholder should execute
the Discovery Written Consent. See "Financial Advisors--Discovery" and Annex B
attached hereto.
 
INCOME TAX TREATMENT
 
  The Merger is intended to qualify as a reorganization under Section 368(a) of
the Internal Revenue Code of 1986, as amended (the "Code"), in which case no
gain or loss generally should be recognized by the holders of shares of
Discovery Stock on the exchange of their shares of Discovery Stock solely for
shares of Ansan Stock, except that gain shall be recognized to the extent of
cash, if any, received in lieu of fractional shares of Ansan Common Stock. As a
condition to the consummation of the Merger, each of Discovery and Ansan will
have received an opinion from their respective counsel that the Merger will
constitute a "reorganization" within the meaning of Section 368(a) of the Code.
However, all Discovery stockholders are urged to consult their own tax
advisors. See "Terms of the Merger--Certain Federal Income Tax Considerations."
 
                                       4

 
ACCOUNTING TREATMENT
 
  As Discovery's stockholders will hold approximately 92% of the outstanding
shares of the merged entity, on a fully diluted basis, the Merger will be
treated as an acquisition of Ansan by Discovery. The Merger will be accounted
for using the purchase method, whereby the purchase price will be allocated
based on the fair value of the Ansan assets acquired and liabilities assumed.
It is anticipated that a significant portion of the purchase price will be
allocated to in-process research and development which will result in a charge
to the consolidated statement of operations of approximately $2.9 million in
the quarter in which the Merger closes. The amount of the estimated charge is
based on a preliminary evaluation and could vary upon completion of a final
valuation analysis. See "Terms of the Merger--Accounting Treatment of the
Merger."
 
                                   THE MERGER
 
EFFECT OF THE MERGER
 
  At the time the Merger becomes effective in accordance with the Certificate
of Merger to be filed with respect thereto (the "Effective Time"), Discovery
will be merged with and into Ansan, and Ansan will be the surviving
corporation.
 
EFFECTIVE TIME OF THE MERGER
 
  The Effective Time will occur when the Certificate of Merger is filed with
the Delaware Secretary of State. The Effective Time is currently expected to
occur on a date as soon as practicable after approval of the Merger Proposal at
the Ansan Special Meeting and pursuant to the Discovery Written Consent,
subject to the satisfaction or waiver of the conditions precedent to the Merger
as set forth in the Merger Agreement. See "Terms of the Merger--Conditions to
the Merger."
 
TERMS OF THE MERGER
 
  As a result of the Merger (but without giving effect to the Ansan Certificate
Amendment), each outstanding share of Discovery Common Stock (other than
shares, if any, as to which appraisal rights have been exercised pursuant to
the DGCL) will be converted into 1.167471 shares of Ansan Common Stock (the
"Common Exchange Ratio"). Additionally, as a result of the Merger, each
outstanding share of Discovery Series A Preferred Stock (other than shares, if
any, as to which appraisal rights have been exercised pursuant to the DGCL)
will be converted into one share of Ansan Series B Preferred Stock (the
"Preferred Exchange Ratio" and, together with the Common Exchange Ratio, the
"Exchange Ratios"). The Merger Agreement provides that all Ansan Series A
Preferred Stock held by Discovery prior to the Effective Time will be cancelled
effective as of the Effective Time. Each share of Ansan Series B Preferred
Stock will be convertible into 4.669884 shares of Ansan Common Stock (without
giving effect to the Ansan Certificate Amendment), subject to adjustment in
certain circumstances. See "Terms of the Merger--Manner and Basis of Converting
Shares," and "Description of Ansan Capital Stock" for a description of the
Ansan Common Stock and Ansan Series B Preferred Stock to be issued in the
Merger.
 
  In connection with the Merger Agreement, Ansan and Titan entered into a
sublicensing agreement on July 15, 1997 (the "Titan Sublicense Agreement"). The
Titan Sublicense Agreement provides that, as of the Effective Time, Ansan will
sublicense certain rights to certain drug compounds to Titan in exchange for
the cancellation of all Ansan Common Stock owned by Titan and the provision of
a 2% net royalty payable by Titan to Ansan from net sales of the drug compounds
sublicensed by Ansan to Titan. Additionally, the Merger Agreement provides that
debt in the amount of approximately $1,200,000 will be repaid by Ansan to Titan
at the Effective Time. See "Information Concerning Ansan--Relationship with
Titan Pharmaceuticals, Inc."

                                       5

   
  Pursuant to the Certificate of Merger to be filed in connection with the
Merger, at the Effective Time, Ansan's name will be changed from Ansan
Pharmaceuticals, Inc. to Discovery Laboratories, Inc. A vote in favor of the
Merger Proposal will also be a vote in favor of the change of name set forth
above.     
 
EXCHANGE RATIOS
 
  Pursuant to the terms of the Merger, each outstanding share of Discovery
Common Stock will be converted into shares of Ansan Common Stock at the Common
Exchange Ratio and each outstanding share of Discovery Series A Preferred Stock
will be converted into shares of Ansan Series B Preferred Stock at the
Preferred Exchange Ratio. Based upon the Exchange Ratios and the number of
shares of Discovery Stock and Ansan Stock outstanding as of the Discovery
Record Date and Ansan Record Date, respectively, and assuming that: (i) no
Discovery or Ansan stockholders exercise appraisal rights; and (ii) no
outstanding Discovery or Ansan options or warrants are exercised prior to the
Merger, approximately 9,516,524 shares of Ansan Common Stock will be
outstanding upon consummation of the Merger, of which approximately 7,877,225
shares (approximately 83% of the total) will be held by the former holders of
Discovery Common Stock, and approximately 2,200,256 shares of Ansan Series B
Preferred Stock will be outstanding, all of which will be held by the former
holders of Discovery Series A Preferred Stock. The Merger Agreement provides
that all outstanding shares of Ansan Series A Preferred Stock held by Discovery
prior to the Effective Time shall be cancelled as of the Effective Time.
 
  Exchange of certificates evidencing shares of Discovery Common Stock and
Discovery Series A Preferred Stock for certificates evidencing shares of Ansan
Common Stock and Ansan Series B Preferred Stock will be made upon surrender of
such certificates to Ansan's transfer agent. CERTIFICATES SHOULD NOT BE
SURRENDERED FOR EXCHANGE PRIOR TO THE APPROVAL OF THE MERGER BY THE
STOCKHOLDERS OF ANSAN AND DISCOVERY. Discovery stockholders will be provided
with a letter of transmittal and related materials needed to exchange their
certificates after such approval. See "Terms of the Merger--Manner and Basis of
Converting Shares" and "Terms of the Merger--Exchange of Certificates."
 
THE BOARD OF DIRECTORS AND MANAGEMENT OF THE COMBINED COMPANY FOLLOWING THE
MERGER
   
  Immediately following the consummation of the Merger, the Board of Directors
of the entity surviving the Merger (the "Combined Company") will consist of ten
(10) members, who will be: Vaughan H. J. Shalson and Richard Sperber, each of
whom is presently a director of Ansan (see "Information Concerning Ansan--
Management"); James S. Kuo, Steve H. Kanzer, Evan Myrianthopoulos, Juerg F.
Geigy, Max Link, Herbert H. McDade, Jr. and Mark C. Rogers, each of whom is
presently a director of Discovery (see "Information Concerning Discovery--
Management"), and David Naveh, Ph.D., who is a nominee of D.H. Blair Investment
Banking Corp. See "Terms of the Merger--Management After the Merger."     
 
  After the Merger, James S, Kuo, currently Chief Executive Officer of
Discovery will be the Chief Executive Officer of the Combined Company. Other
principal officers of the Combined Company will be Evan Myrianthopoulos, who
will serve as Chief Operating Officer of the Combined Company, and Robert
Capetola, who will serve as the Chief Executive Officer of Acute Therapeutics,
Inc. ("ATI"), a majority-owned subsidiary of Discovery that will be a majority-
owned subsidiary of the Combined Company. See "Terms of the Merger--Management
After the Merger."
 
CONDITIONS TO THE MERGER; TERMINATION
   
  Notwithstanding approval of the Merger Proposal by the stockholders of Ansan
and Discovery, the consummation of the Merger is subject to a number of
conditions which, if not fulfilled or waived, permit unilateral termination of
the Merger Agreement. These conditions include the maintenance by Discovery of
specified working capital, and compliance by Ansan with a specified operating
budget. The Merger Agreement may also be terminated by mutual consent. See
"Terms of the Merger--Conditions to the Merger" and "Terms of the Merger--
Termination or Amendment of Merger Agreement".     
 
                                       6

 
GOVERNMENTAL AND REGULATORY APPROVALS
 
  Ansan and Discovery are not aware of any governmental or regulatory approvals
required for consummation of the Merger, other than compliance with federal and
applicable state securities laws and the filing and recording of the
Certificate of Merger as required under the DGCL.
 
VOTING AGREEMENTS
 
  Certain stockholders of Discovery and Ansan have agreed to vote their shares
in favor of the Merger and the Merger Agreement pursuant to the Discovery
Voting Agreements and the Titan Voting Agreement.
 
RESTRICTIONS ON RESALE
 
  Under the terms of the Merger Agreement, as a condition to Ansan's obligation
to consummate the Merger, stockholders of Discovery holding at least 85% of the
Discovery Stock, on an as-converted basis, must agree to certain restrictions
on resale for a period of up to twelve months. See "Terms of Merger--Voting
Agreements;" "--Affiliates' Restrictions on Sale of Ansan Common Stock" and "--
Additional Restrictions on Sales of Ansan Common Stock."
 
APPRAISAL RIGHTS
 
  Both Ansan and Discovery stockholders are entitled to certain rights under
the DGCL to receive cash for their shares provided that they follow certain
prescribed statutory procedures. The failure of a stockholder to follow the
appropriate procedure may result in the termination or waiver of such rights.
See "Terms of the Merger--Appraisal Rights."
 
                                 RECENT EVENTS
 
  To ensure that Ansan had sufficient assets and capital to satisfy the
requirements for Nasdaq listing pending completion of the Merger, Ansan and
Discovery entered into a Series A Preferred Stock Purchase Agreement on July
16, 1997 which provided for the purchase of 13,000 shares of Ansan Series A
Preferred Stock by Discovery in exchange for the payment of $1,300,000 (the
"Series A Purchase Agreement"). The Merger Agreement was executed concurrently
with the Series A Purchase Agreement. The Ansan Series A Preferred Stock is
convertible into Ansan Common Stock. The conversion rate applicable to the
Ansan Series A Preferred Stock is subject to reset upon the occurrence of
certain events, including, generally, failure of the Merger to be consummated
by December 31, 1997 for reasons not attributable to the conduct of Discovery.
In the event of such reset, the conversion rate shall be reset to that rate
which will permit the holders of the Ansan Series A Preferred Stock to convert
such stock into approximately 51% of the voting securities of Ansan (without
taking into account certain outstanding Ansan warrants). For additional details
on the Series A Purchase Agreement and certain restrictions on the operations
of Ansan arising therefrom, see "The Merger And Related Transactions--
Background to the Merger."
 
  An NASD hearing was held on July 17, 1997 to consider the potential delisting
of Ansan's Common Stock from the Nasdaq SmallCap Market and Ansan's application
for continued listing by way of a temporary exemption from the NASD's capital
and surplus requirements. The NASD reviewed the Merger Agreement and the Series
A Purchase Agreement and ruled that Ansan would have a temporary exemption from
such listing requirements until July 31, 1997, at which time certain filings
would be required to be made with the Securities and Exchange Commission (the
"Commission") evidencing Ansan's eligibility for continued listing. Such
filings were made on a timely basis. Ansan must provide a monthly internal
balance sheet to the NASD and make certain other filings until November 30,
1997. In the event that Ansan fails to comply with any of the NASD
requirements, the Ansan Common Stock will be immediately delisted from the
Nasdaq SmallCap Market.
 
                                       7

 
                       PRICE RANGE OF ANSAN COMMON STOCK
 
  The Ansan Common Stock is traded on the Nasdaq SmallCap Market under the
symbol "ANSN." In addition, Ansan's units (consisting of Ansan Common Stock,
Class A Warrants and Class B Warrants), Class A Warrants and Class B Warrants
are approved for listing on the Nasdaq SmallCap Market. As of August 31, 1997,
the number of stockholders of record of Ansan's Common Stock was approximately
12, and the number of beneficial owners of shares of Ansan Common Stock held in
street name was approximately 600. As of August 31, 1997, there were
approximately 2,851,954 shares of Ansan Common Stock outstanding.
 
  The following table sets forth the quarterly price ranges of the Ansan Common
Stock in fiscal year 1996 and the first two quarters of fiscal year 1997, as
reported by Nasdaq.

                                                                    LOW    HIGH
                                                                  ------- ------
                                                                    
   Fiscal 1996
     Quarter Ended March 31, 1996...............................  $ 3.625 $5.250
     Quarter Ended June 30, 1996................................    4.000  5.125
     Quarter Ended September 30, 1996...........................    2.500  4.750
     Quarter Ended December 31, 1996............................    2.000  3.125
   Fiscal 1997
     Quarter Ended March 31, 1997...............................  $ 2.125 $3.250
     Quarter Ended June 30, 1997................................    1.250  2.000
     Quarter Ended September 30, 1997...........................   1.1875   2.00
     Quarter Ended December 31, 1997 (through October 20, 1997).    1.375  1.375

  On July 17, 1997, the last trading day prior to the first public announcement
by Ansan and Discovery concerning the combination of the two companies, the
closing price of the Ansan Common Stock reported on the reporting system for
Nasdaq was $1.50 per share. On October 20, 1997, the closing bid price of Ansan
Common Stock as reported on the reporting system for Nasdaq was $1.3125 per
share.     
 
  Following the Merger, it is anticipated that Ansan Common Stock will continue
to be traded on the Nasdaq under the symbol "ANSN" until such time as a new
symbol is chosen reflecting the change of Ansan's name.
 
  Ansan has not paid dividends on the Ansan Common Stock. It is anticipated
that the Combined Company will not pay dividends on the Ansan Common Stock in
the foreseeable future. Holders of Ansan Series A Preferred Stock are entitled
to receive dividends at any time such dividends are paid with respect to Ansan
Common Stock with the entitlement thereto determined as an amount equal to the
dividend that would be paid on such share if it were converted into shares of
Ansan Common Stock. In the event that a dividend is declared on any other class
or series of Ansan preferred stock, the Ansan Series A Preferred Stock shall
then become entitled to payment of a dividend equal to the proportion that the
liquidation preference of a share of the Ansan Series A Preferred Stock bears
to the liquidation preference of a share of such other Ansan preferred stock
unless holders of at least 66.67% of the Ansan Series A Preferred Stock consent
otherwise. There can be no assurance that Ansan will have earnings sufficient
to pay dividends on the Ansan Stock at any time in the future.
 
                                       8

 
            SELECTED HISTORICAL AND PRO FORMA FINANCIAL INFORMATION
 
  The following selected historical financial information of Ansan at December
31, 1995 and 1996 and for each of the two years in the period ended December
31, 1996 has been derived from, and should be read in conjunction with, Ansan's
audited historical financial statements and the notes thereto and management
discussion and analysis of financial condition and Plan of Operations included
elsewhere in this Prospectus/Proxy Statement. The selected historical financial
information as of June 30, 1997 and for the six month periods ended June 30,
1996 and 1997 are derived from unaudited interim condensed financial statements
of Ansan included elsewhere in this Prospectus/Proxy Statement, and, in the
opinion of management, reflect all adjustments (consisting only of normal
recurring adjustments) necessary for the fair presentation of Ansan's results
for such periods.
 
  The following selected historical consolidated financial information of
Discovery at December 31, 1996 and for each of the two years in the period
ended December 31, 1996 has been derived from, and should be read in
conjunction with, Discovery's historical consolidated financial statements and
the notes thereto and management's discussion and analysis of financial
condition and Plan of Operations included elsewhere in this Prospectus/Proxy
Statement. The selected historical consolidated balance sheet information at
December 31, 1995 has been derived from audited financial statements not
included elsewhere herein. The selected historical consolidated financial
information as of June 30, 1997 and for the six month periods ended June 30,
1996 and 1997 are derived from unaudited interim consolidated condensed
financial statements of Discovery which are included elsewhere in this
Prospectus/Proxy Statement and include, in the opinion of management, all
adjustments (consisting only of normal recurring adjustments) necessary for the
fair presentation of Discovery's results for such periods.
 
  The selected pro forma condensed financial information has been derived from
the pro forma combined condensed financial statements, which give effect to the
Merger as a purchase, and should be read in conjunction with such pro forma
statements and the notes thereto included elsewhere in this Prospectus/Proxy
Statement. The pro forma condensed consolidated financial statements for the
year ended December 31, 1996 have been prepared based upon the audited
financial statements of Ansan for the year then ended and the audited
consolidated financial statements of Discovery for the year then ended. The pro
forma condensed combined financial statements as of and for the six months
ended June 30, 1997 have been prepared based upon the unaudited condensed
financial statements of Ansan and the unaudited condensed consolidated
financial statements of Discovery as of June 30, 1997 and for the six months
then ended.
 
  The Merger will be accounted for using the purchase method of accounting.
Although Ansan will be the surviving corporate entity, Discovery's current
stockholders will own approximately 92% of the merged entity on an as-converted
to common stock basis. Accordingly, the transaction will be accounted for as an
acquisition of Ansan by Discovery. The unaudited pro forma condensed
consolidated financial statements have been prepared on the basis of
assumptions described in the notes thereto and include assumptions relating to
the allocation of the consideration paid for the assets and liabilities of
Ansan based on preliminary estimates of their fair value. The actual allocation
of such consideration may differ from that reflected in the unaudited pro forma
condensed combined financial statements after final valuation procedures are
completed following the closing of the Merger. The final allocations of the
aggregate purchase price for the Merger is not expected to differ materially
from the preliminary allocations. In the opinion of Ansan and Discovery, all
adjustments necessary to present fairly the unaudited pro forma condensed
combined financial statements have been made based on the proposed terms and
structure of the Merger.
 
                                       9

                   SELECTED HISTORICAL FINANCIAL INFORMATION
               (IN THOUSANDS, EXCEPT SHARE AND PER SHARE AMOUNTS)

                                                                        PERIOD FROM
                                                                       INCORPORATION
                               YEAR ENDED         SIX MONTHS ENDED     (NOVEMBER 6,
 ANSAN PHARMACEUTICALS        DECEMBER 31,            JUNE 30,             1992)
 ---------------------    ---------------------  --------------------   TO JUNE 30,
                             1995       1996       1996       1997         1997
                          ----------  ---------  ---------  ---------  -------------
                                                        
Historical Statement of Operations
 Data:
  Research and
   development expenses.  $    1,421  $   1,181  $     463  $     627    $  6,608
  General and
   administrative
   expenses.............       1,048      1,257        442        529       3,443
  Net loss..............      (2,821)    (2,281)      (812)    (1,146)    (10,226)
  Pro forma net loss per
   share(1).............       (1.93)
  Shares used in
   computing pro forma
   net loss per
   share(1).............   1,464,713
  Net loss per share(1).                  (0.94)     (0.34)     (0.46)
  Shares used in
   computing net loss
   per share(1).........              2,431,447  2,406,145  2,484,937

                           AS OF DECEMBER 31,
                          ---------------------  JUNE 30,
                             1995       1996       1997
                          ----------  ---------  ---------
                                        
Historical Balance Sheet
 Data:
  Cash, cash equivalents
   and short-term
   investments..........  $    3,854  $   1,746  $   1,698
  Working capital.......       3,624      1,496        386
  Total assets..........       3,981      1,923      1,818
  Total liabilities.....         338        334      1,344
  Deficit accumulated
   during the
   development stage....      (6,799)    (9,080)   (10,226)
  Total stockholders'
   equity...............       3,643      1,589        474

                                                                        PERIOD FROM
                                                                       INCORPORATION
                               YEAR ENDED         SIX MONTHS ENDED       (MAY 18,
 DISCOVERY LABORATORIES       DECEMBER 31,            JUNE 30,             1993)
 ----------------------   ---------------------  --------------------   TO JUNE 30,
                             1995       1996       1996       1997         1997
                          ----------  ---------  ---------  ---------  -------------
                                                        
Historical Consolidated Statement
 of Operations Data:
  Research and
   development expenses.  $      --   $   2,740  $      22  $   2,257    $  4,997
  General and
   administrative
   expenses.............          17        692          9      1,345       2,055
  Net loss..............         (17)    (3,236)       (33)    (3,296)     (6,550)
  Pro forma net loss per
   share (2)............       (0.01)     (0.65)     (0.01)     (0.42)
  Shares used in
   computing pro forma
   net loss per share
   (2)..................   1,714,766  4,943,768  3,028,329  7,836,363

                           AS OF DECEMBER 31,
                          ---------------------  JUNE 30,
                             1995       1996       1997
                          ----------  ---------  ---------
                                        
Historical Consolidated
 Balance Sheet Data:
  Cash, cash equivalents
   and short-term
   investments..........  $        3  $  17,400  $  14,797
  Working capital.......           3     17,188     14,536
  Total assets..........           3     18,189     14,947
  Total liabilities.....         --         231        296
  Deficit accumulated
   during the
   development stage....         (18)    (3,254)    (6,550)
  Total stockholders'
   equity...............           3     15,758     12,451

- --------
(1) See Note 1 of the Ansan Financial Statements for information concerning the
    computation of net loss per share.
(2) See Note B of the Discovery Financial Statements for information concerning
    the computation of net loss per share.
 
                                       10

               SELECTED PRO FORMA CONDENSED FINANCIAL INFORMATION
               (IN THOUSANDS, EXCEPT SHARE AND PER SHARE AMOUNTS)

                                      YEAR ENDED DECEMBER 31, 1996
                               -------------------------------------------------
                                                                      PRO FORMA
                                                                       COMBINED
                                                      PRO FORMA       REFLECTING
                                 ANSAN    DISCOVERY  ADJUSTMENTS        MERGER
                               ---------  ---------  -----------      ----------
                                                          
Statement of Operations Data:
  Research and development
   expenses................... $   1,181  $   2,740    $  --          $   3,921
  General and administrative
   expenses...................     1,257        692       --              1,949
  Net loss....................    (2,281)    (3,236)      --             (5,517)
  Net loss per share..........     (0.94)     (0.65)      --              (0.84)
  Shares used in computing net
   loss per share............. 2,431,447  4,943,768                   6,583,068

                                     SIX MONTHS ENDED JUNE 30, 1997
                               -------------------------------------------------
                                                                      PRO FORMA
                                                                       COMBINED
                                                      PRO FORMA       REFLECTING
                                 ANSAN    DISCOVERY  ADJUSTMENTS        MERGER
                               ---------  ---------  -----------      ----------
                                                          
Statement of Operations Data:
  Research and development
   expenses................... $     627  $   2,257    $  --          $   2,884
  General and administrative
   expenses...................       529      1,345       --              1,874
  Net loss....................    (1,146)    (3,296)        6 (A)        (4,436)
  Net loss per share..........     (0.46)     (0.42)      --              (0.47)
  Shares used in computing net
   loss per share............. 2,484,937  7,836,363                   9,475,664

                                             JUNE 30, 1997
                               -------------------------------------------------
                                                                      PRO FORMA
                                                                       COMBINED
                                                      PRO FORMA       REFLECTING
                                 ANSAN    DISCOVERY  ADJUSTMENTS        MERGER
                               ---------  ---------  -----------      ----------
                                                          
Balance Sheet Data:
  Cash, cash equivalents and
   short-term investments..... $   1,698  $  14,797    (1,189)(B)     $  15,306
  Working capital.............       386     14,536      (950)(C)        13,972
  Total assets................     1,818     14,947    (1,189)(B)        15,576
  Total liabilities...........     1,344        296      (239)(B)(C)      1,401
  Deficit accumulated during
   the development stage......   (10,226)    (6,550)    7,291 (D)        (9,485)
  Total stockholders' equity..       474     12,451      (950)(C)        11,975

- --------
(A) Reflects the net reduction of interest expenses as a result of the
    repayment of the outstanding Titan debt in connection with the Merger.
 
(B) Reflects the repayment of obligations to Titan in connection with the
    Merger.
 
(C) Reflects the estimated costs incurred by Ansan and Discovery to complete
    the Merger.
 
(D) Reflects the net allocation of the estimated purchase price of $2.9 million
    to the historical Ansan balance sheet. The adjustment includes
    approximately $2.9 million of purchased in-process research and
    development. Also reflects the elimination of Ansan's stockholders' equity
    accounts.
 
                                       11

COMPARATIVE PER SHARE DATA
 
  The following table sets forth certain historical per share data of Ansan and
Discovery and combined per share data on an unaudited pro forma basis after
giving effect to the Merger as a purchase assuming that each share of Discovery
Common Stock will be converted into 1.167471 shares of Ansan Common Stock and
each share of Discovery Series A Preferred Stock will be converted into one
share of Ansan Series B Preferred Stock. The per share data of Ansan and
Discovery presented below is presented as of and for the year ended December
31, 1996 and as of and for the six months ended June 30, 1997. The pro forma
combined share data presented below combines Ansan's per share data for the
year ended December 31, 1996 and for the six months ended June 30, 1997 with
Discovery's per share data for the same periods. This data should be read in
conjunction with the selected historical financial information, the unaudited
condensed pro forma combined financial statements and the separate historical
financial statements of Ansan and Discovery and the notes thereto included
elsewhere in this Prospectus/Proxy Statement. The unaudited condensed pro forma
combined financial statements are not necessarily indicative of the operating
results or financial position that would have been achieved had the Merger been
consummated at the beginning of the period presented and should not be
construed as representative of future operations.

                                                YEAR ENDED     SIX MONTHS ENDED
                                             DECEMBER 31, 1996  JUNE 30, 1997
                                             ----------------- ----------------
                                                         
Ansan
  Historical net loss per common share......      $(0.94)           $(0.46)
  Book value per share......................        0.56              0.17
Discovery
  Pro forma net loss per common share.......      $(0.65)           $(0.42)
  Book value per common share(/1/) .........       (2.08)            (2.57)
Pro Forma Combined Per Ansan Share:
  Pro forma combined net loss per common
   share....................................      $(0.84)           $(0.47)
  Pro forma combined book value per common
   share(/1/) ..............................                         (1.87)
Equivalent Pro Forma Combined Per Discovery
 Share:(/2/)
  Pro forma combined net loss per common
   share....................................      $(0.84)           $(0.55)
  Pro forma combined book value per common
   share(/1/) ..............................                         (2.18)

- --------
(/1/Book)value per common share amounts determined after deducting preferred
    stock liquidation preferences of $13.50 per share.
(/2/Equivalent)pro forma combined amounts are calculated based on the pro forma
    combined amounts multiplied by the Exchange Ratio.
 
                                       12

                          FORWARD LOOKING STATEMENTS
 
  Certain of the statements set forth in this Prospectus/Proxy Statement,
including, without limitation, Ansan's, Discovery's and the Combined Company's
research and development programs, the seeking of joint development or
licensing arrangements with pharmaceutical companies, the research and
development of particular compounds and technologies for particular
indications are forward-looking and based upon Ansan's and Discovery's current
belief as to the outcome, occurrence and timing of future events or current
expectations and plans. All such statements involve significant risks and
uncertainties. Many important factors affect the Combined Company's ability to
achieve the stated outcomes and to successfully develop and commercialize its
product candidates including, among other things, the ability to obtain
substantial additional funds, to obtain and maintain all necessary patents or
licenses, to demonstrate the safety and efficacy of product candidates at each
stage of development, to meet applicable regulatory standards and receive
required regulatory approvals, to meet obligations under its license
agreements, to be capable of producing drug candidates in commercial
quantities at reasonable costs, to successfully compete against other products
and to market products in a profitable manner. As a result, there also can be
no assurance that these statements included herein will prove to be accurate.
In light of the significant uncertainties inherent in these statements
included herein, the inclusion of such information should not be regarded as a
representation by Ansan, Discovery or the Combined Company, or any other
person, that the objectives and plans of Ansan, Discovery or the Combined
Company will be achieved.
 
                                 RISK FACTORS
 
  The following factors should be considered carefully by stockholders of
Ansan and Discovery in evaluating whether to approve and adopt the Merger
Agreement. The risks associated with the Combined Company will be additional
risks faced by both the Ansan stockholders and the Discovery stockholders
following the Merger. The risks described that are currently specific to
Discovery will be additional risks faced by stockholders of Ansan following
the Merger. The risks described that are currently specific to Ansan will be
additional risks faced by Discovery stockholders following the Merger.
 
RISKS RELATED TO THE MERGER:
 
 Difficulties and Cost of Integration
 
  The anticipated benefits of the Merger will not be achieved unless Ansan and
Discovery are successfully combined in a smooth and timely manner. That
combination will require integration of the Combined Company's research and
development and administrative operations, including the relocation of Ansan's
executive offices, which are currently in California, to Discovery's executive
offices, which are in New York. The transition to a combined company will
require substantial attention from management, which has limited experience in
integrating companies. Moreover, the management of the Combined Company may
include personnel who are not currently employed by either Ansan or Discovery.
The diversion of management attention and any difficulties encountered in the
transition process could have an adverse impact on the ability of the Combined
Company to successfully pursue the development of the drug candidates expected
to be retained by the Combined Company. Moreover, the costs of the Merger
(including redundant operating costs that may be incurred for a period of time
following consummation of the Merger) are anticipated to be very substantial.
In addition, the rate at which cash is used by the Combined Company will
exceed substantially the rate at which cash is presently used by either Ansan
or Discovery. The risks associated with the absorption by the Combined Company
of these expenses and ongoing cash requirements will increase the pressure on
the Combined Company to achieve synergistic cost reductions as rapidly as
possible and, if the Combined Company is unable to do so, its financial
position may be impaired. There can be no assurance of the extent to which
cost savings and efficiencies will be achieved by the Combined Company.
Moreover, although the companies believe that beneficial synergies will result
from the Merger, there can be no assurance that combining the two companies'
businesses, even in an efficient, effective and timely manner, will result in
combined results of operations and financial condition superior to what would
have been achieved by each company independently.
 
                                      13

 Dilution
 
  The shares of Ansan Common Stock and Ansan Series B Preferred Stock to be
issued to Discovery stockholders at the Effective Time are expected to
represent approximately 92% of the outstanding equity securities on an as-
converted basis of the Combined Company immediately after the Effective Time
(exclusive of certain currently outstanding Ansan warrants). In addition,
seven of the ten members of the Combined Company's Board of Directors
immediately following the Effective Time will be former members of the Board
of Directors of Discovery. Accordingly, the Merger will have the effect of
reducing the percentage voting interest in Ansan represented by a share of
Ansan Common Stock and the percentage voting interest in Discovery represented
by a share of Discovery Common Stock. However, as a result of the Merger,
stockholders of Ansan and Discovery will each own a voting interest in a
larger enterprise.
 
  Common Stockholders of Discovery will experience an immediate dilutive
effect on net tangible book value per share of $.32, or approximately 20%, and
stockholders of Ansan will experience an immediate accretive effect on net
tangible book value per share of $.97, or approximately 335%, upon
consummation of the Merger. However, holders of Ansan Series B Preferred Stock
will have an aggregate liquidation preference which will exceed the net
stockholders' equity of the Combined Company. Whether the Merger will in fact
be accretive or dilutive to Ansan stockholders with respect to net tangible
book value per share will depend on the actual results achieved by the
Combined Company in the future as compared to the results that could have been
achieved by Ansan on a stand-alone basis over the same period, given the
number of shares of Ansan Common Stock to be issued to Discovery stockholders
in the Merger. No assurance can be given as to such future results and,
accordingly, as to whether the Merger will be accretive or dilutive to Ansan
stockholders with respect to future net tangible book value per share.
 
  Holders of Discovery Series A Preferred Stock will receive 2,200,256 shares
of Ansan Series B Preferred Stock. At the Effective Time, based on the initial
conversion price, each share of Series B Preferred Stock will be convertible
at the option of the holder thereof into approximately 4.67 shares of Common
Stock of the Combined Company. The conversion price in effect immediately
prior to the first anniversary of the Effective Time (the "Reset Date") will
be adjusted effective as of the Reset Date if the average closing bid price of
the Ansan Common Stock for the 30 consecutive trading days immediately
preceding the Reset Date is less than $2.89 (as adjusted for any stock split
and the like). Any such reset of the conversion price applicable to the Ansan
Series B Preferred Stock could increase the number of shares of the Combined
Company's Common Stock into which each share of Series B Preferred Stock is
convertible to a maximum of 9.34 shares and would have a dilutive effect on
the holders of Ansan Common Stock.
 
 Control by Current Officers, Directors and Principal Stockholders
 
  Upon closing of the Merger, the directors, executive officers and principal
stockholders of Discovery will beneficially own approximately 46.45% of the
Common Stock of the Combined Company. Accordingly, the Combined Company's
executive officers, directors, principal stockholders and certain of their
affiliates will have the ability to exert substantial influence over the
election of the Combined Company's Board of Directors and the outcome of
issues submitted to the Combined Company's stockholders. Such a concentration
of ownership may have the effect of delaying or preventing a change in control
of the Combined Company, including transactions in which stockholders might
otherwise recover a premium for their shares over their current market prices.
See "Principal Stockholders."
 
 Risks Associated with Fixed Exchange Ratios
 
  Under the terms of the Merger Agreement, each share of Discovery Common
Stock issued and outstanding at the Effective Time will be converted into the
right to receive 1.167471 shares of Ansan Common Stock and each share of
Discovery Series A Preferred Stock issued and outstanding at the Effective
Time will be converted into the right to receive one share of Ansan Series B
Preferred Stock. The Exchange Ratios will not be adjusted in the event of any
increase or decrease in the price of Ansan Common Stock prior to the Effective
Time. The price of the Ansan Common Stock at the Effective Time may vary from
the price of the Ansan Common Stock at the date of this Prospectus/Proxy
Statement and at the date of the Ansan Special Meeting. Such variations
 
                                      14

may be the result of changes in the business, operations or prospects of Ansan
or Discovery, market assessments of the likelihood that the Merger will be
consummated and the timing thereof, general market and economic conditions and
other factors. There can be no assurance that the price of the Ansan Common
Stock on the date of the Ansan Special Meeting or the date as of which any
Discovery stockholder determines whether to consent to the Merger Proposal
will be indicative of the price of the Ansan Common Stock at the Effective
Time. Moreover, there can be no assurance of the degree to which the price of
the Common Stock of the Combined Company (and therefore the value ultimately
received by Discovery stockholders in consideration of their Discovery Stock)
will be related to the price of the Ansan Common Stock prior to the Merger.
The market prices of the Ansan Common Stock as of recent dates are set forth
herein under "Price Range of Ansan Common Stock."
 
 Uncertainty of Listing on Nasdaq Small Cap Market; Possible Delisting from
 Nasdaq SmallCap Market; Market Illiquidity
 
  In April 1997, Ansan received a letter from the NASD indicating that Ansan
was no longer in compliance with the maintenance requirements for continued
listing on the Nasdaq SmallCap Market. Ansan had a hearing before the NASD
Listing Qualifications Panel on July 17, 1997, at which time the NASD granted
Ansan a temporary exemption from the NASD's capital and surplus requirements
conditioned upon, among other things, completion of the Merger.
   
  After the Merger, to meet the current Nasdaq listing requirements for these
securities to continue to be listed on the Nasdaq SmallCap Market, (i) the
Combined Company will have to maintain at least $2 million in total assets and
$1 million in capital and surplus; (ii) the minimum bid price of the Combined
Company's Common Stock will have to be at least $1.00 per share; (iii) there
will have to be at least 100,000 shares in the public float valued at $200,000
or more; (iv) the Combined Company's Common Stock will have to have at least
two active market makers, and (v) the Combined Company's Common Stock will
have to be held by at least 300 holders. Nasdaq recently adopted new
requirements for continued listing on the Nasdaq SmallCap Market. Commencing
February 22, 1998, the Combined Company, in order to preserve the listing of
its securities, will have to maintain (a) (1) at least $2 million in net
tangible assets, (2) $35 million in market capitalization, or (3) $500,000 in
net income (over two of the last three years), (b) a public float of at least
500,000 shares valued at $1 million or more and (c) a minimum bid price of
$1.003. The shareholder and market maker requirements will not be altered.
       
  In addition, because the Merger will result in a significant change in
control and financial structure, the Combined Company will be required to
comply with the new listing standards applicable to the Nasdaq SmallCap
Market. These new listing criteria are more stringent than the maintenance
criteria described above and, under the recently adopted revisions to the
Nasdaq listing criteria, would require that (i) the Combined Company have $4
million in net tangible assets (or $50 million in market capitalization or
$750,000 in net income over two of the last three years), (ii) the minimum bid
price of the Combined Company's Common Stock be at least $4.00, (iii) there be
at least 1 million shares in the public float valued at $5 million or more,
(iv) the Combined Company's Common Stock have at least three active market
makers, (v) the Combined Company's Common Stock be held by at least 300
holders, and (iv) the Combined Company have a one-year operating history or a
$50 million market capitalization. In addition, under both the initial listing
and maintenance requirements, the Combined Company will be required to comply
with certain corporate governance standards.     
 
  For purposes of determining compliance with the public float requirements
described above, shares of stock held by officers, directors and 10%-or-
greater stockholders are excluded.
 
  Ansan has indicated to the NASD that it intends to effect the Reverse Stock
Split for the purpose of complying with the applicable and potentially
applicable listing criteria described above. There can be no assurance,
however, that the price of Ansan's or the Combined Company's Common Stock will
increase proportionately with the decrease in the number of shares, or that
any price increase resulting from the Reverse Stock Split can be sustained for
any period of time. Accordingly, subsequent reverse stock splits could be
required in order to comply with minimum bid requirements. Based on the shares
of Common Stock of the
 
                                      15

Combined Company expected to be outstanding immediately following the
Effective Time, any cumulative reverse split ratio in excess of approximately
five-to-one would result in the Combined Company failing to meet the minimum
public float requirement in the absence of conversion of shares of preferred
stock or the exercise of options or warrants. Accordingly, there can be no
assurance that the Combined Company will be capable of complying with all of
the listing criteria required to be complied with to continue a Nasdaq
SmallCap Market listing.
 
  If the Combined Company is unable to satisfy the NASD's new listing and
maintenance requirements, the Combined Company's securities may be delisted
from Nasdaq. In such event, trading, if any, in the Combined Company's
securities would thereafter be conducted in the over-the-counter market in the
so-called "pink sheets" or on the NASD's "OTC Electronic Bulletin Board."
Consequently, the liquidity of the Combined Company's securities could be
impaired, not only in the number of securities which could be bought and sold,
but also through delays in the timing of the transactions, reduction in
securities analysts' and the news media's coverage of the Combined Company,
and lower prices for the Combined Company's securities than might otherwise be
attained.
 
 Combined Company; Lack of Business Plan
 
  Neither Ansan nor Discovery has developed an operating plan pertaining to
the Combined Company after the Effective Time or made any decisions on which
drug candidates will be funded and at what rate such funding will be provided.
There can be no assurance that the Combined Company will continue with the
funding of any of the drug candidates discussed herein.
 
 Risks of Low-Priced Stock; Possible Effect of "Penny Stock" Rules on
 Liquidity for the Common Stock
 
  If the Combined Company's securities were to be delisted from the Nasdaq
SmallCap Market, they could become subject to Rule 15g-9 under the Exchange
Act, which imposes additional sales practice requirements on broker-dealers
which sell such securities to persons other than established customers and
"accredited investors" (generally, individuals with net worth in excess of
$1,000,000 or annual incomes exceeding $200,000, or $300,000 together with
their spouses). For transactions covered by this rule, a broker-dealer must
make a special suitability determination for the purchaser and have received
the purchaser's written consent to the transaction prior to sale.
Consequently, the rule may adversely affect the ability of broker-dealers to
sell the Combined Company's securities and may adversely affect the ability of
purchasers in this offering to sell any of the securities acquired hereby in
the secondary market.
 
  The Commission has adopted regulations which define a "penny stock" to be an
equity security that has a market price (as therein defined) less than $5.00
per share or with an exercise price of less than $5.00 per share, subject to
certain exceptions. For any transaction involving a penny stock, unless
exempt, the rules require delivery, prior to any transaction in a penny stock,
of a disclosure schedule prepared by the Commission relating to the penny
stock market. Disclosure is also required to be made about commissions payable
to both the broker-dealer and the registered representative and current
quotations for the securities. Finally, monthly statements are required to be
sent disclosing recent price information for the penny stock held in the
account and information on the limited market in penny stocks.
 
  The foregoing required penny stock restrictions will not apply to the
Combined Company's securities if such securities continue to be listed on the
Nasdaq SmallCap Market and have certain price and volume information provided
on a current and continuing basis or meet certain minimum net tangible assets
or average revenue criteria. There can be no assurance that the Combined
Company's securities will qualify for exemption from these restrictions. In
any event, even if the Combined Company's securities were exempt from such
restrictions, it would remain subject to Section 15(b)(6) of the Exchange Act,
which gives the Commission the authority to prohibit any person that is
engaged in unlawful conduct while participating in a distribution of a penny
stock from associating with a broker-dealer or participating in a distribution
of a penny stock, if the Commission finds that such a restriction would be in
the public interest. If the Combined Company's securities were subject to the
existing or proposed rules on penny stocks, the market liquidity for the
Combined Company's securities could be severely adversely affected.
 
                                      16

RISKS RELATED TO BUSINESS AND OPERATIONS:
 
 Development Stage of Discovery and Ansan; No Developed or Approved Products;
 Uncertainty of Future Profitability
 
  Discovery and Ansan are development stage companies. The potential products
upon which the Combined Company intends to focus its development efforts are
in the research and development stage and, accordingly, neither Discovery nor
Ansan have begun to market or generate revenues from the commercialization of
any of these products under development. The Combined Company's products under
development will require significant time-consuming and costly research,
development, preclinical studies, clinical testing, regulatory approval and
significant additional investment prior to their commercialization, which may
never occur. Such clinical testing activities, together with resultant
increases in general and administrative expenses, are expected to result in
significant additional operating losses for the foreseeable future. Neither
Discovery nor Ansan is currently profitable and it is expected that the
Combined Company will not generate significant product revenues for the
foreseeable future, if at all. It is expected that the Combined Company will
incur significant increasing operating losses over the next several years. To
achieve profitable operations, the Combined Company, alone or with others,
must successfully develop and obtain regulatory approval for marketing its
products.
 
  The Combined Company's operations will be subject to numerous risks
associated with the establishment and development of products based upon
innovative or novel technologies. As a result, the Combined Company will be
subject to the problems, delays, uncertainties and complications encountered
in connection with newly founded development stage life science businesses.
Some of these unanticipated problems may include development, regulatory,
manufacturing, distribution and marketing difficulties that may be beyond the
Combined Company's financial or technical abilities to satisfactorily resolve.
In particular, there can be no assurance that the Combined Company's proposed
drug products will not cause adverse effects that may prevent them from being
marketed, regardless of their efficacy. Certain of Discovery's and Ansan's
initial drug candidates have not been the subject of Phase I clinical trials,
the purpose of which include identifying adverse effects, or have not been the
subject of such clinical trials at the dosage levels at which Discovery and
Ansan anticipate they will be administered in treating the indications for
which Discovery and Ansan are exploring their use. Moreover, those that have
been the subject of previous clinical trials may be shown to have previously
undetected adverse effects during the more extensive clinical trials that will
be required prior to their becoming candidates for marketing approval by the
United States Food and Drug Administration (the "FDA"). There can be no
assurance that the research and development activities funded by the Combined
Company will be successful, that products under development will prove to be
safe and effective, that any of the preclinical or clinical development work
will be completed, that the Combined Company will ever achieve any of its New
Drug Application ("NDA") filing objectives with the FDA, that FDA approval
will be attained for such products, that the anticipated products will be
commercially viable or successfully marketed, that third parties do not hold
proprietary rights that will preclude the Combined Company from marketing its
products, if any, or that, if the products under development are approved by
the FDA, the Combined Company will ever achieve significant revenues or
profitable operations. See "Information Concerning Discovery" and "Information
Concerning Ansan."
 
 Extensive Government Regulation; Uncertainty of FDA and Other Governmental
 Approval of Products Under Development
 
  The testing, manufacture, distribution, advertising and marketing of drug
products are subject to extensive regulation by governmental authorities in
the United States and other countries. Prior to marketing, any pharmaceutical
products developed or licensed by the Combined Company must undergo an
extensive regulatory approval process required by the FDA and by comparable
agencies in other countries. This process, which includes preclinical studies
and clinical trials of each pharmaceutical compound to establish its safety
and effectiveness and confirmation by the FDA that good laboratory, clinical
and manufacturing practices were maintained during testing and manufacturing,
can take many years, requires the expenditure of substantial resources and
will give larger companies with greater financial resources a competitive
advantage over the Combined Company. The FDA review process can be lengthy,
and the Combined Company may encounter
 
                                      17

delays or rejections of its applications when submitted. If questions arise
during the FDA review process, approval may take a significantly longer period
of time. Generally, in order to gain FDA approval, a company must conduct
preclinical studies in a laboratory and in animal models to obtain preliminary
information on a compound's efficacy and to identify any safety problems. The
results of these studies are submitted as part of an investigational new drug
("IND") application that the FDA must review before human clinical trials of
an investigational drug can start. Clinical trials are normally done in three
phases and generally take two to five years or longer to complete.
 
  The regulatory status of Discovery's three products under development is as
follows:
 
 SuperVent(TM)
 
  SuperVent(TM) is an aerosolized, multidimensional therapy for airway
diseases characterized by inflammation, injurious oxidation and excessive
sputum. The active compound in SuperVent(TM) is tyloxapol, which has been used
safely as an emulsifying agent in drug formulations by the pharmaceutical
industry for over 40 years. The FDA has approved, subject to certain
modifications, the first two clinical studies to be conducted pursuant to a
physician-sponsored IND application for a randomized, double-blinded, placebo-
controlled Phase I/II clinical trial of SuperVent(TM) for the treatment of
cystic fibrosis ("CF"). Discovery entered into a clinical research agreement
with the University of Utah Health Sciences Center ("UHSC") and began the
aforementioned trial on March 17, 1997 pursuant to such agreement. Ten normal
volunteers were administered SuperVent(TM) by inhalation pursuant to the first
part of this three-part study. Five of ten additional subjects are expected to
be enrolled during the third quarter of 1997. Following completion of the
first part of the study, the results will be analyzed by UHSC. Should the drug
be deemed safe to study in patients with CF, a second part of the study will
be initiated at UHSC following institutional review board approval. Discovery
will meet with the FDA's Division of Pulmonary Drugs to review second part
outcomes and a proposed third part (multi-center) study before such third part
of the Phase I/II clinical trial begins. Assuming successful completion of the
Phase I/II clinical trial of SuperVent(TM), Discovery anticipates that, at a
minimum, at least one additional large-scale, multi-center, Phase III clinical
trial will be necessary before Discovery will be able to submit an NDA to the
FDA requesting marketing approval for SuperVent(TM) for the treatment of CF.
 
 KL/4/-Surfactant
 
  KL/4/-Surfactant is a proprietary, synthetic lung surfactant invented at The
Scripps Research Institute ("Scripps") and initially licensed to affiliates of
Johnson & Johnson, Inc. ("J&J"). ATI has acquired an exclusive, worldwide
sublicense to KL/4/-Surfactant from J&J. In July 1992, an IND submitted by
Scripps relating to the use of KL/4/-Surfactant to treat infant respiratory
distress syndrome ("IRDS") was approved by the FDA. A Phase II clinical trial
was subsequently completed by J&J. In 1991, an IND was submitted by J&J
relating to the use of KL/4/-Surfactant to treat adult respiratory distress
syndrome ("ARDS") and was subsequently approved by the FDA. Both the IRDS IND
and ARDS IND have been transferred to ATI. ATI has received FDA approval to
amend the approved ARDS IND and re-initiate Phase II clinical trials of KL/4/-
Surfactant for the treatment of ARDS. The ARDS trial was initiated on August
15, 1997 at Sharp Memorial Hospital in San Diego, California. ATI has amended
the existing IRDS IND to permit the initiation of Phase II clinical trials of
KL/4/-Surfactant to treat meconium aspiration syndrome ("MAS") and such
clinical trial was commenced on May 27, 1997 at Thomas Jefferson University
Hospital in Philadelphia.
 
 ST-630
 
  ST-630 is an active Vitamin D analog. Discovery intends to file an IND to
initiate Phase I clinical studies of ST-630 as a once-daily, orally
administered drug for the treatment of postmenopausal osteoporosis in the
United States during 1997. Discovery is currently preparing for submission
such an IND that includes preclinical studies, chemistry manufacturing and
control information and a proposed Phase I trial. Following receipt of FDA
approval, if granted, Discovery intends to conduct an initial dose-ranging
study of ST-630 in humans. Based upon the results of the dose-ranging study,
Discovery may then either seek to further optimize the delivery of
 
                                      18

ST-630 by testing one or more alternative means of delivery or, assuming
acceptable results, seek to initiate a large-scale, multi-center clinical
trial in the United States. Discovery has access to preclinical data generated
by Sumitomo Pharmaceuticals ("Sumitomo") and Taisho Pharmaceuticals ("Taisho")
with respect to ST-630 pursuant to the terms of the licensing arrangements
described herein with respect to ST-630. Discovery has not had any discussions
with the FDA regarding ST-630.
 
  The regulatory status of Ansan's products under development that will be
retained by the Combined Company is as follows:
 
 Apafant Injection
 
  Apafant is a receptor antagonist of the proinflammatory mediator, platelet
activating factor. Ansan met with the FDA on November 7, 1996, for a pre-IND
meeting to discuss its plans to study the injectable form of Apafant ("Apafant
Injection") for the treatment of patients with acute pancreatitis. Ansan
intends to file an IND in the second half of 1997 and following receipt of FDA
approval, if granted, Ansan intends to initiate a Phase Ib/II clinical trial
in patients with acute pancreatitis. Based on the discussion with the FDA,
Ansan plans to initiate testing in patients with mild acute pancreatitis. In
order to identify clinical endpoints for future trials, Ansan also intends to
enroll patients with severe acute pancreatitis in the second part of the
study. To support its plans to initiate testing in acute pancreatitis
patients, Ansan is relying on preclinical and clinical safety data provided by
Boehringer Ingelheim GmbH ("Boehringer Ingelheim") (the licensor of the
Apafant product) that were obtained with the oral and nasal forms of Apafant
for other indications. There can be no assurance that upon review of the IND,
the FDA will approve Ansan's plans to include patients with severe acute
pancreatitis in the planned two-part study (or to conduct any clinical trials
of Apafant Injection), nor is there any assurance that the FDA will agree that
the dose levels selected by Ansan for the first study are acceptable. Clinical
development of the drug will incur significant delays if the FDA restricts the
first study to patients with mild disease or requires the use of lower doses.
 
  Ansan is aware that British Biotechnology, PLC ("BBP") is currently
developing lexipafant, trademarked as Zacutex(TM), another platelet activating
factor antagonist, for the treatment of patients with pancreatitis. BBP is
currently engaged in Phase III clinical trials in the United States and has
filed for marketing approval in the European Union ("EU"). If lexipafant is
approved prior to Apafant, it may increase the cost and time required to
obtain approval of Apafant or limit the indications for which Apafant may be
marketed if it is approved. There can be no assurance that Apafant will prove
more efficacious than lexipafant in treating patients with pancreatitis or, if
FDA approval is obtained, that Apafant will gain wider market acceptance.
 
 AN10 Topical
 
  AN10 is a novel analog of butyric acid. Ansan met with the FDA on February
10, 1997, for a pre-IND meeting to discuss its plans to study the topical form
of AN10 ("AN10 Topical") for the prevention of chemotherapy-induced alopecia
in cancer patients. Ansan intends to file an IND in the second half of 1997
and following receipt of FDA approval, if granted, Ansan intends to initiate a
Phase I trial to assess the safety of a single dose of AN10 Topical
administered to normal volunteers. Assuming that acceptable safety of AN10 is
demonstrated in this first study, Ansan will need to complete additional
preclinical studies before it will be able to initiate repeated dose clinical
trials in cancer patients receiving chemotherapy. These preclinical studies
include repeated dose toxicity studies in two animal species as well as
pharmacokinetic studies. There can be no assurance that the current
formulation of AN10 Topical will be found to have acceptable safety in either
the preclinical studies or the first clinical trial in order to enable testing
in patients.
 
 Novaheme(TM) (AN10) Injection
 
  Novaheme(TM) is an intravenous formulation of AN10 that is intended for
treatment of patients with beta-hemoglobinopathies, such as sickle cell anemia
and beta-thalassemia. Currently, Novaheme(TM) is in preclinical testing and
there have been no discussions with the FDA about potential plans to file an
IND or initiate clinical studies. To initiate clinical testing, Ansan would
need to complete additional subacute and subchronic preclinical toxicity
studies and there is no assurance that the current formulation of Novaheme(TM)
will be found to have an acceptable safety profile in these studies.
 
                                      19

  The regulatory status of the Ansan drug candidates that will be sublicensed
to Titan pursuant to the Titan Sublicense Agreement is as follows:
 
 Pivanex(TM) (AN9) Injection
 
  Pivanex(TM) Injection ("Pivanex(TM) ") is an injectable form of AN9, another
novel analog of butyric acid. In the fourth quarter of 1994, Ansan filed an
IND for Pivanex(TM) for the treatment of patients with cancer. In the first
quarter of 1995, the FDA approved Ansan's plans to conduct a rising-dose open-
label Phase Ib clinical trial for the use of Pivanex(TM) in patients with
solid tumors refractory to standard chemotherapy. The primary objective of the
Phase Ib trial is to determine the maximum tolerated dose ("MTD") of
Pivanex(TM). From August to December 1995, Ansan initiated several discussions
with the FDA in order to modify the design of this study and to facilitate
enrollment of patients. The FDA approved the protocol changes and the study
was initiated in January 1996. Fifteen patients have been enrolled to date and
nine dose levels have been studied. Pivanex(TM) has been well tolerated in the
study and the MTD has not yet been reached. Mild, transient elevations of
hepatic transaminases have been observed in two patients. No patients have
been discontinued for drug-related adverse events and no dose modification has
been required in any patient. Ansan is continuing the Phase Ib study in order
to find the MTD. There can be no assurance that dose levels that are found to
be well-tolerated will subsequently be found to be efficacious in the
treatment of cancer. There have been no discussions with the FDA about plans
for future clinical trials.
 
 AN9 Topical
 
  Ansan met with the FDA on September 17, 1996, to discuss its plans to file
an IND to initiate clinical testing of a topical form of AN9 for the treatment
of patients with cutaneous malignancies. Based on the discussion with the FDA,
Ansan will need to complete additional preclinical studies, including repeated
dose toxicity studies in two species, in order to initiate a Phase Ib trial in
patients. There can be no assurance that the current formulation of AN9
Topical will be found to have acceptable safety in these preclinical studies.
 
  Pursuant to the Titan Sublicense Agreement, Titan will acquire substantial
rights to Ansan's Pivanex(TM) and AN9 Topical products. See "Information
Concerning Ansan--Relationship With Titan Pharmaceuticals, Inc."
 
  Upon completion of clinical trials of a new drug product, FDA and foreign
regulatory authority marketing approval must be obtained before the new drug
product can be sold. NDAs submitted to the FDA generally take one to three
years to be approved. If questions arise during the FDA review process,
approval may take a significantly longer period of time. The testing and
approval processes require substantial time and effort and there can be no
assurance that any approval will be granted on a timely basis, if at all. Even
if regulatory clearances are obtained, a marketed product is subject to
continual review, and later discovery of previously unknown problems or
failure to comply with the applicable regulatory requirements may result in
restrictions on the marketing of a product or withdrawal of the product from
the market as well as possible civil or criminal sanctions. For marketing
outside the United States, the Combined Company also will be subject to
foreign regulatory requirements governing human clinical trials and marketing
approval for pharmaceutical products. The requirements governing the conduct
of clinical trials, product licensing, pricing and reimbursement vary widely
from country to country. None of Discovery's and Ansan's products under
development have been approved for marketing in the United States or elsewhere
(nor has testing been completed). No assurance can be given that the Combined
Company will be able to obtain regulatory approval for any such products under
development. Failure to obtain requisite governmental approvals or failure to
obtain approvals of the scope requested will delay or preclude the Combined
Company or its licensees or marketing partners from marketing the Combined
Companies' products under development, or limit the commercial use of such
products, and thereby could have a material adverse effect on the Combined
Company's business, financial condition and results of operations.
 
 Technological Uncertainty and Obsolescence
 
  The market for biotechnology is characterized by rapidly changing technology
and evolving industry standards. The Combined Company's future success will
depend upon its ability to develop and commercialize
 
                                      20

its existing products and to develop new products and applications. There can
be no assurance that the Combined Company will successfully complete the
development of Discovery's or Ansan's current or future products or that such
products will achieve market acceptance. Any delay or failure of such products
under development or any future product which may develop in achieving market
acceptance would adversely affect the Combined Company's business.
 
  Discovery's and Ansan's products under development are intended to treat
diseases for which other technologies and proposed treatments are rapidly
developing. There can be no assurance that any results of Discovery's or
Ansan's research and product development efforts will not be rendered obsolete
by research efforts and technological activities of others, including the
efforts and activities of governments, major research facilities and large
multinational corporations.
 
 Need for Additional Financing; Issuance of Securities; Future Dilution
 
  In the future, the Combined Company will require substantial additional
funding to conduct its research and product development activities and to
manufacture and market, if approved by the FDA or corresponding foreign
regulatory authorities, the products currently under development by Discovery
and (to the extent retained by the Combined Company) Ansan and any other
products that the Combined Company may develop in the future. Further funds
may be raised through collaborative ventures entered into with potential
corporate partners and/or additional debt or equity financings. While the
Combined Company may seek to enter into collaborative ventures with corporate
partners to fund some or all of its research and development activities, as
well as to manufacture or market any products which may be successfully
developed, Discovery and Ansan currently do not have any such arrangements
with corporate partners. Discovery and Ansan have not made arrangements to
obtain any additional financing and there can be no assurance that the
Combined Company will be able to obtain adequate additional financing on
acceptable terms, if at all, or that any such additional financing would not
result in significant dilution of stockholders' interests. Failure by the
Combined Company to enter into collaborative ventures or to receive additional
funding to complete its proposed product development programs would have a
material adverse effect on the Combined Company. If additional financing is
not otherwise available, the Combined Company will be required to modify its
business development plans or reduce or cease certain or all of its
operations.
 
 Dependence on Patents, Licenses and Protection of Proprietary Rights; Risk of
 Loss of Technology
 
  In order to justify the substantial investment of time and expense required
to develop and commercialize its products, the Combined Company will seek
proprietary protection for its drug candidates so as to prevent others from
commercializing equivalent products in substantially less time and at
substantially lower expense. The pharmaceutical industry places considerable
importance on obtaining patent and trade secret protection for new
technologies, products and processes. The Combined Company's success will
depend in part on the ability of the Combined Company and its licensors to
obtain effective patent protection for the Combined Company's proprietary
technologies and products, defend such patents, preserve its trade secrets and
operate without infringing upon the proprietary rights of others, both in the
United States and in other countries. The patent position of firms relying
upon biotechnology is highly uncertain and involves complex legal and factual
questions. To date, there has emerged no consistent policy at the United
States Patent and Trademark Office ("PTO") regarding the breadth of claims
allowed in biotechnology patents or the degree of protection afforded under
such patents.
 
  There are various United States and foreign patents and patent applications
(including international applications filed under the Patent Cooperation
Treaty) that have been issued or filed with respect to the products and
technologies under development by Discovery and Ansan. See "Information
Concerning Discovery--Patents, Licenses and Proprietary Rights" and
"Information Concerning Ansan--Patents and Proprietary Rights." These patents
and patent applications have been licensed to Discovery or Ansan, as the case
may be. Although the licensors under such licenses have retained control of
the patent prosecution process, the Combined
 
                                      21

Company will be responsible for the expenses of prosecuting the patents and
patent applications (i.e., the fees of patent counsel and any domestic or
foreign filing fees that are applicable). Patent applications may be expected
to remain pending for several years before the issuance of a patent, if any,
and the prosecution of patent applications with respect to the Combined
Company's products may entail considerable expense to the Combined Company.
 
  There can be no assurance that patents will issue as a result of any of the
pending patent applications relating to Discovery's or Ansan's products and
technologies or that the issued patents and any patents resulting from the
pending patent applications will be sufficiently broad to afford protection to
the Combined Company against competitors with similar products and
technologies. In addition, there can be no assurance that such patents will
not be challenged, invalidated or circumvented, or that the rights granted
thereunder will provide competitive advantages to the Combined Company. The
commercial success of the Combined Company will also depend upon its avoidance
of infringement of patents issued to competitors. A United States patent
application is maintained under conditions of confidentiality while the
application is pending, so the Combined Company will not be able to determine
the inventions being claimed in pending patent applications filed by third
parties. Litigation may be necessary to defend or enforce the Combined
Company's patent and license rights or to determine the scope and validity of
the proprietary rights of others. Defense and enforcement of patent claims can
be expensive and time-consuming, even in those instances in which the outcome
is favorable to the Combined Company, and can result in the diversion of
substantial resources from the Combined Company's other activities. An adverse
outcome could subject the Combined Company to significant liabilities to third
parties, require the Combined Company to obtain licenses from third parties,
or require the Combined Company to alter its products or processes or cease
altogether any related research and development activities or product sales,
any of which could have a material adverse effect on the Combined Company's
business, financial condition and results of operations. See "Information
Concerning Discovery--Patents, Licenses and Proprietary Rights" and
"Information Concerning Ansan--Patents and Proprietary Rights."
 
  Ansan is aware of the existence of prior art references which may affect the
validity of certain claims in the issued patent, which claims broadly cover
AN10, among other compounds. Reexamination of such patent by the PTO, in light
of these references, may be necessary in order to obtain valid claims which
are both free of the prior art and which specifically cover AN10. In the
course of preparing for reexamination or otherwise, additional prior art may
be uncovered which might affect the validity of such proposed narrow claims.
Such art would need to be brought to the attention of the PTO in connection
with any reexamination. Moreover, there can be no assurance that the PTO will
grant a request for reexamination, or if granted, that such reexamination will
result in the issuance of the desired claims. In any event, given that the
already-uncovered prior art references relate to compounds but not to methods
of treatment, the existence of such references would not, as a matter of
United States patent law, be expected to affect any claims directed to the use
of AN10 to treat fetal beta-hemoglobinopathies as covered in United States
Patent No. 5,569,675 issued in October 1996, which Ansan has licensed from
Bar-Ilan Research and Development Co., Ltd. ("Bar-Ilan").
 
  Ansan also is aware of certain issued United States patents (the "Perrine
patents") which appear to cover the administration of butyric acid, during
gestation or infancy, to ameliorate beta-globin disorders, including sickle
cell anemia and beta-thalassemia, by increasing the level of fetal hemoglobin.
To the extent that AN10 converts to butyric acid and in the event the Combined
Company's commercial activities include administration of AN10 during
gestation and/or infancy, such activities could give rise to issues of
infringement of the Perrine patents.
 
  Discovery and Ansan each require all employees to enter into confidentiality
agreements that prohibit the disclosure of confidential information to third
parties and require disclosure and assignment to Discovery or Ansan,
respectively, of rights to such employees' ideas, developments, discoveries
and inventions while so employed. In addition, Ansan and Discovery seek to
obtain such agreements from its consultants, advisors and research
collaborators. To the extent that consultants, key employees or other third
parties apply technological information independently developed by them or by
others to any of the proposed projects of the Combined Company, disputes may
arise as to the proprietary rights to such information which may not be
resolved in favor
 
                                      22

of the Combined Company. In addition, the Combined Company will rely on trade
secrets and proprietary know-how that it will seek to protect in part by
confidentiality agreements with its employees, consultants, advisors or
others. There can be no assurance that these agreements will not be breached,
that the Combined Company would obtain adequate remedies for any breach, or
that the Combined Company's trade secrets or proprietary know-how and will not
otherwise become known or be independently developed by competitors in such a
manner that the Combined Company has no legal recourse.
 
  The Combined Company will be dependent on licensing arrangements for access
to its products under development, and the Combined Company will be required
to make certain payments and satisfy certain performance obligations in order
to maintain the effectiveness of such licensing arrangements. The Combined
Company will be responsible pursuant to its licensing agreements for the cost
of filing and prosecuting patent applications and maintaining issued patents.
See "Information Concerning Discovery--Patents, Licenses and Proprietary
Rights" and "Information Concerning Ansan--Patents and Proprietary Rights." If
the Combined Company does not meet its due diligence and/or financial
obligations under its license agreements in a timely manner, the Combined
Company could lose the rights to its proprietary technology, which would have
a material adverse effect on the Combined Company. In addition, in the case of
Ansan's license of Apafant from Boehringer Ingelheim (the "Boehringer
Ingelheim License Agreement"), such license may be required to be reconveyed
to Boehringer Ingelheim in the event that Boehringer Ingelheim exercises an
option granted in the Boehringer Ingelheim License Agreement, following which
Boehringer Ingelheim would have the right to develop and commercialize Apafant
and would be obligated to make milestone and royalty payments to the Combined
Company. Should Boehringer Ingelheim exercise this option and then fail to
pursue development of Apafant on a good faith efforts basis consistent with
good business judgment in any of certain countries, then the rights to Apafant
in the country with respect to which the failure occurs shall again revert to
Ansan.

 Dependence on Third Party Suppliers; Lack of Manufacturing Capability
 
  Neither Ansan nor Discovery has any manufacturing capacity of its own and
the Combined Company will be required to rely on outside manufacturers to
produce appropriate clinical grade material for its use in clinical studies
for certain of its products. To be successful, the Combined Company's products
must be manufactured in commercial quantities under good manufacturing
practice ("GMP") requirements presented by the FDA at acceptable costs. The
FDA periodically inspects manufacturing facilities in the United States in
order to assure compliance with applicable GMP requirements. Foreign
manufacturers are also inspected by the FDA if their drugs are marketed in the
United States. Failure of the foreign or domestic suppliers of the Combined
Company's products or failure of the manufacturers of the Combined Company's
products to comply with GMP regulations or other FDA regulatory requirements
would have a material adverse effect on the Combined Company's business,
financial condition and results of operations.
 
  The active compound in Discovery's SuperVent(TM) product under development,
tyloxapol, is presently manufactured for several third parties pursuant to GMP
standards by an affiliate of Sanofi-Winthrop, Inc. ("Sanofi"), a multinational
pharmaceutical company. Sanofi is the sole supplier of tyloxapol with GMP
standard manufacturing capabilities and there are few alternative non-GMP
approved sources of supply. Currently, Discovery purchases bulk tyloxapol on
an as-needed basis from Sanofi. The Combined Company is not expected to have
an agreement with Sanofi to supply any additional material either in
connection with a Phase III clinical trial or, following regulatory approval,
for marketing purposes. In addition, the Combined Company does not intend to
enter into an agreement for supply of the formulated drug containing tyloxapol
until the Combined Company plans to initiate a Phase III clinical trial. There
can be no assurance that the Combined Company will be able to enter into a
supply agreement with Sanofi or a supplier of the formulated drug on terms
acceptable to the Combined Company, if at all. In such case, the Combined
Company would be required to seek alternate manufacturing sources capable of
producing tyloxapol and the formulated drug. There can be no assurance that
the Combined Company will be able to identify and contract with alternative
manufacturers on terms acceptable to it, if at all. Any interruption in the
supply of tyloxapol would have a material adverse effect on the Combined
Company's business, financial condition and results of operations.
 
                                      23

  ATI has acquired from J&J experimental compounds, the KL/4/ peptides and
manufacturing equipment needed to produce and meet its requirements for
clinical supplies of KL/4/-Surfactant. ATI has entered into an agreement with
Cook Imaging Corporation for the development of the manufacturing process to
be employed in the KL/4/-Surfactant program. There can be no assurance that
agreement for such production will be reached. Failure to identify and reach
an agreement with a third party manufacturer would substantially delay ATI's
development of KL/4/-Surfactant and could have a material adverse effect on
the Combined Company's business, financial condition and results of
operations.
 
  Tetrionics, Inc. ("Tetrionics") manufactures and supplies Discovery with ST-
630 for Discovery's investigational and commercial purposes. Tetrionics
presently also manufactures and supplies ST-630 to Penederm, Inc. for
investigational topical use for the treatment of psoriasis. It is anticipated
that the Combined Company will have no long-term agreement with Tetrionics or
any other supplier for ST-630. Any interruption of the Combined Company's
supply of ST-630 could substantially delay the Combined Company's development
efforts with respect to ST-630 and could have a material adverse effect on the
Combined Company.
 
  The active compound (AN10) in Ansan's Novaheme(TM) Injection and AN10
Topical products has previously been manufactured by Chemsyn. It is expected
that the Combined Company will seek an agreement with Chemsyn to supply AN10
for future planned preclinical and clinical studies. There can be no assurance
that an agreement with Chemsyn will be reached or, if an agreement is reached,
that Chemsyn will be able to successfully manufacture the active compound to
the Combined Company's specifications. Novaheme(TM) Injection and AN10 Topical
are currently manufactured by Pharmaceutical Development Center ("PDC"). There
can be no assurance that PDC will agree to manufacture these products to meet
the Combined Company's future needs to supply its clinical trials. It is
anticipated that prior to marketing, if any, a new commercial manufacturer of
Novaheme(TM) Injection and of AN10 Topical will need to be identified,
qualified under GMP standards, and its manufacturing process validated in a
manner acceptable to regulatory authorities. There can be no assurance that a
new manufacturer can be identified, qualified, and validated on a timely
basis. There can be no assurance that the Combined Company will not experience
delays or other supply problems that may materially affect its research and
development efforts or that the Combined Company will be able to obtain an
alternate source of supplies on a timely basis.
 
  The active compound (AN9) in Ansan's Pivanex(TM) Injection and AN9 Topical
products is presently manufactured by Raylo Chemicals and purchased by Ansan
on an as-needed basis. There can be no assurance that Raylo Chemicals will
agree to supply the active compound in the future. Pivanex Injection and AN9
Topical are currently manufactured from the active compound by PDC. There can
be no assurance that PDC will agree to manufacture these products to meet
Ansan's future needs to supply its clinical trials. It is anticipated that
prior to marketing, if any, a new commercial manufacturer of Pivanex Injection
and of AN9 Topical will need to be identified, qualified under GMP standards,
and its manufacturing process validated in a manner acceptable to regulatory
authorities. There can be no assurance that a new manufacturer can be
identified, qualified, and validated on a timely basis. There can be no
assurance that the Combined Company will not experience delays or other supply
problems that may materially affect its research and development efforts or
that the Combined Company will be able to obtain an alternate source of
supplies on a timely basis.
 
  The active compound in Ansan's Apafant Injection is presently manufactured
by Boehringer Ingelheim. Boehringer Ingelheim has agreed to provide sufficient
supplies of the active compound for completion of the planned clinical trial
in accordance with the Boehringer Ingelheim License Agreement. Boehringer
Ingelheim has also agreed to provide additional supplies of the active
compound to Ansan for a fee, or to allow Ansan to have the active compound
manufactured by a third party supplier. There can be no assurance that
Boehringer Ingelheim, if requested to provide additional supplies, will be
able to do so on a timely basis. It is anticipated that potentially
significant delays may be encountered if a third party must be identified to
manufacture additional supplies. There can be no assurance that a third party
supplier can be identified or that it will be able to successfully manufacture
the active compound to the Combined Company's specifications. Apafant
Injection is currently manufactured by PDC. There can be no assurance that PDC
will agree to manufacture these products
 
                                      24

to meet the Combined Company's future needs to supply its clinical trials. It
is anticipated that prior to marketing, if any, a new commercial manufacturer
of Apafant Injection will need to be identified, qualified under GMP
standards, and its manufacturing process validated in a manner acceptable to
regulatory authorities. There can be no assurance that a new manufacturer can
be identified, qualified, and validated on a timely basis. There can be no
assurance that the Combined Company will not experience delays or other supply
problems that may materially affect its research and development efforts or
that the Combined Company will be able to obtain an alternate source of
supplies on a timely basis.
 
 Dependence on Others for Clinical Development of, Regulatory Approvals for,
 and Manufacturing and Marketing of Pharmaceutical Products
 
  Ansan's and Discovery's strategy has been, and the Combined Company's
strategy will be, to seek to enter into collaborative agreements with
pharmaceutical companies for the research and development, clinical testing,
manufacturing, marketing and commercialization of certain of its products. The
Combined Company will therefore be dependent upon the expertise and dedication
of sufficient resources by third parties to develop and commercialize certain
of its proposed products. The Combined Company may in the future grant to its
collaborative partners, if any, rights to license and commercialize any
pharmaceutical products developed under these collaborative agreements and
such rights would limit the Combined Company's flexibility in considering
alternatives for the commercialization of such products. Under such
agreements, the Combined Company expects to rely on its collaborative partners
to conduct research and clinical trials, manufacture, market and commercialize
certain of its products. Although the Combined Company believes that its
collaborative partners may have an economic motivation to commercialize the
pharmaceutical products which they may license from the Combined Company, the
amount and timing of resources devoted to these activities generally will be
controlled by each such individual partner. There can be no assurance that the
Combined Company will be successful in establishing any collaborative
arrangements, or that, if established, such future partners will be successful
in developing and commercializing products or that the Combined Company will
derive any revenues from such arrangements.
 
  Discovery has recently entered into a clinical research agreement with UHSC
for clinical trials of SuperVent(TM) in the treatment of CF. This Phase I/II
clinical trial began on March 17, 1997.
 
  ATI and Scripps have entered into a sponsored research agreement (the
"Sponsored Research Agreement") supporting continuing research by Charles G.
Cochrane, M.D., and Susan Revak of Scripps. Pursuant to the Sponsored Research
Agreement, ATI will contribute $460,000 annually to Scripps' KL/4/-Surfactant
research efforts for an initial two-year period. ATI has an option to acquire
an exclusive worldwide license to make, have made, sell or use technology
developed under the agreement, which it is required to exercise within 180
days from receipt of notice from Scripps of the development of such
technology. Scripps will own all technology that it develops pursuant to work
performed under the Sponsored Research Agreement. ATI has the right to receive
50% of the net royalty income received by Scripps for inventions jointly
developed by ATI and Scripps to the extent ATI does not exercise its option
with respect to such inventions. ATI has entered into consulting agreements
with certain research personnel at Scripps.
 
  Discovery has not entered into any collaborative arrangements with respect
to its ST-630 product.
 
 Lack of Marketing Capability and Experience
 
  It is anticipated that, over the long-term, the Combined Company will
manufacture and market certain of its products through a direct sales force,
if and when necessary regulatory approvals are obtained. Ansan and Discovery
currently have no marketing and sales experience and no marketing or sales
personnel. Unless a sales force is established, the Combined Company will be
dependent on corporate partners or other entities for the marketing and
selling of its products. There can be no assurance that the Combined Company
will be able to enter into any satisfactory arrangements for the marketing and
sale of its products. The inability of the Combined
 
                                      25

Company to successfully establish a sales force or enter into third party
distribution, marketing and selling arrangements for its anticipated products
would have a material adverse effect on the Combined Company's business,
financial condition and results of operations.
 
 Dependence Upon Key Personnel and Consultants
 
  The Combined Company will be highly dependent upon its officers and
directors, as well as its scientific advisory board members, consultants and
collaborating scientists. Since competent management personnel and personnel
capable of performing the foregoing functions are in great demand, there can
be no assurance that the Combined Company will be able to attract and retain
such personnel on a timely basis and on terms acceptable to the Combined
Company. It is anticipated that the Combined Company's success will depend in
large part upon attracting and retaining highly-skilled managerial and other
employees.
 
 No Assurance of Additional Product
 
  Although the Combined Company intends to devote substantial resources to the
development and commercialization of some or all of the products under
development by Discovery and (to the extent retained by the Combined Company)
Ansan, the Combined Company will explore the acquisition and subsequent
development and commercialization of additional pharmaceutical products and
technologies. There can be no assurance that the Combined Company will be able
to identify any additional products or technologies, that it will be able to
license any such technologies on acceptable terms or that, even if suitable
products or technologies are identified, the Combined Company will have
sufficient resources to pursue any such products or technologies to
commercialization.
 
 Competition
 
  The Combined Company will be engaged in a highly competitive field.
Competition from numerous existing companies and potential new entrants is
intense and expected to increase. Many of these companies have substantially
greater research and development, manufacturing, marketing, financial,
technological, personnel and managerial resources than the Combined Company.
There can be no assurance that any products developed by the Combined
Company's competitors will not be more effective than any developed by the
Combined Company. In addition, colleges, universities, governmental agencies
and other public and private research organizations are becoming more active
in seeking patent protection and licensing arrangements to collect royalties
for use of technology that they have developed, some of which may be directly
competitive with the technologies to be developed by the Combined Company.
These institutions will also compete with the Combined Company in recruiting
highly qualified scientific personnel. It is expected that therapeutic
developments in the areas in which the Combined Company will be active may
occur at a rapid rate and that competition will intensify as advances in this
field are made. Accordingly, the Combined Company will be required to continue
to devote substantial resources and efforts to research and development
activities.
 
 Risk of Product Liability; No Insurance Coverage
 
  Should the Combined Company develop any products, the marketing of such
products, through third party arrangements or otherwise, may expose the
Combined Company to product liability claims in the event that the use or
misuse of pharmaceutical products manufactured by, or under license from, the
Combined Company results in adverse effects. Discovery presently carries
product liability insurance relating to its Phase I/II clinical trial of
SuperVent(TM) and Ansan presently carries the same in relation to its Phase
I/b clinical trial of Pivanex(TM). The Combined Company may be required to
obtain additional product liability insurance coverage prior to initiation of
clinical trials of its other proposed products. It is expected that the
Combined Company will obtain product liability insurance coverage before
commercialization of its proposed products. There can be no assurance that
adequate insurance coverage will be available at an acceptable cost, if at
all. In addition, there can be no assurance that a product liability claim,
even if the Combined Company has insurance coverage, would not materially
adversely affect the Combined Company's business, financial condition and
results of operations.
 
                                      26

 Uncertainty of Product Pricing and Reimbursement; Health Care Reform and
 Related Measures
 
  The levels of revenues and profitability of pharmaceutical and/or
biotechnology products and companies may be affected by efforts of
governmental and third party payers to contain or reduce the costs of health
care through various means. For example, in certain foreign markets, pricing
or profitability of prescription pharmaceuticals is subject to government
control. In the United States, there have been a number of federal and state
proposals to implement similar government control. Presently, the United
States Congress is considering a number of legislative and regulatory reforms
that may affect companies engaged in the health care industry in the United
States. Pricing constraints on the Combined Company's products, if approved,
could have a material adverse effect on the Combined Company. While it cannot
be predicted whether these proposals will be adopted or what effects such
proposals may have on its business, the existence and pendency of such
proposals could in general have a material adverse effect on the Combined
Company. In addition, the Combined Company's ability to commercialize
potential pharmaceutical and/or biotechnology products may be adversely
affected to the extent that such proposals have a material adverse effect on
other companies that are prospective collaborators with respect to any of the
Combined Company's product candidates.
 
  In the United States and elsewhere, successful commercialization of the
Combined Company's products will depend in part on the availability of
reimbursement to the consumer from third party health care payers, such as
government and private insurance plans. There can be no assurance that such
reimbursement will be available or will permit price levels sufficient to
realize an appropriate return on the Combined Company's investment in product
development. Third party health care payers are becoming increasingly cost
conscious in determining which pharmaceutical products they will and will not
reimburse. If the Combined Company succeeds in bringing one or more products
to the market, there can be no assurance that these products will be
considered cost effective and that reimbursement to the consumer will be
available or will be sufficient to allow the Combined Company to sell its
products on a competitive basis. See "Risk Factors" for further discussion on
this and related issues.
 
 Certain Interlocking Relationships; Potential Conflicts of Interest
 
  Steve H. Kanzer, the Chairman of Discovery, is a full-time officer of
Paramount Capital Incorporated ("Paramount Capital") and of Paramount Capital
Investments, LLC ("Paramount Investments"), an affiliate of Paramount Capital.
In addition, Kenneth Johnson, the Director of Business Development of
Discovery, is a Technology Associate of Paramount Investments. See
"Management" and "Certain Transactions". Each of these individuals will devote
only a portion of his time to the business of the Combined Company. Paramount
Capital acted as placement agent for Discovery in a private placement of its
equity securities conducted during June through November 1996 (the "Unit
Offering"). Paramount Investments is a merchant banking firm specializing in
biotechnology companies. In the regular course of its business, Paramount
Investments identifies, evaluates and pursues investment opportunities in
biomedical and pharmaceutical products, technologies and companies. The DGCL
requires that any transactions between Discovery and any of its affiliates be
on terms that, when taken as a whole, are substantially as favorable to
Discovery as those then reasonably obtained from a person who is not an
affiliate in an arm's-length transaction. Nevertheless, Paramount Investments
is not obligated pursuant to any agreement or understanding with Discovery to
make any additional products or technologies available to Discovery, and there
can be no assurance that any biomedical or pharmaceutical product or
technology identified by Paramount Investments or any other affiliates of
Paramount Capital or Paramount Investments in the future will be made
available to the Combined Company.
 
  Lindsay A. Rosenwald, M.D., a director of Titan and a director of Ansan, is
the Chairman and Chief Executive Officer of Paramount Capital. Paramount
Capital acted as placement agent for Titan in a private placement of its
equity securities conducted during 1993. Titan currently owns approximately
32% of the outstanding Ansan Stock on an as-converted basis. In connection
with the Merger, certain drug compounds of Ansan will be sublicensed to Titan
and all of the Ansan Stock owned by Titan will be cancelled. Titan currently
performs certain services for Ansan. Additionally, Louis Bucalo, M.D., the
Chief Executive Officer and a director
 
                                      27

of Titan, also is a director of Ansan. See "The Merger and Related
Transactions--Interests of Certain Persons" and "Information Concerning
Ansan--Relationship with Titan Pharmaceuticals, Inc."
 
  It is anticipated that the Combined Company will adopt a policy consistent
with the policy currently maintained by Discovery to compensate directors of
the Combined Company in the form of cash bonuses and/or stock options, subject
to the approval of a majority of the disinterested directors of the Combined
Company in connection with new drug candidates licensed or acquired by the
Combined Company which were identified and introduced to the Combined Company
by such persons. In addition, certain of the officers, directors, consultants,
and advisors to the Combined Company may from time to time serve as officers,
directors, consultants or advisors to other biopharmaceutical or biotechnology
companies. There can be no assurance that such other companies will not in the
future have interests in conflict with those of the Combined Company.
 
 Potential Adverse Effect of Shares Eligible for Future Sale
 
  Upon completion of the Merger (without giving effect to the Reverse Stock
Split), the Combined Company will have outstanding approximately (i) 9,516,524
shares of Common Stock; (ii) 2,200,256 shares of Series B Preferred Stock;
(iii) 2,207,500 Class A Warrants to purchase an aggregate of 2,207,500 shares
of Common Stock and 2,207,500 Class B Warrants; (iv) 1,495,000 Class B
Warrants to purchase 1,495,000 shares of Common Stock; (v) the Unit Purchase
Option to purchase an aggregate of 520,000 shares of Common Stock, assuming
exercise of the underlying Warrants; (vi) outstanding options to purchase
1,127,660 shares of Common Stock; (vii) 220,026 Warrants to purchase Ansan
Series B Preferred Stock; and (viii) 256,873 Warrants to purchase Common
Stock. The Combined Company will also have 1,187,400 shares of Common Stock
reserved for issuance upon exercise of outstanding options under stock option
plans (assuming that no Discovery or Ansan options are exercised between the
date hereof and the Effective Time). Upon completion of the Merger, Discovery
stockholders, optionholders and warrantholders will receive Common Stock and
common stock equivalents of the Combined Company equal to 20,208,820 shares,
17,640,073 of which will be subject to contractual resale restrictions (the
"Restricted Stock") assuming all of the Discovery stockholders execute the
lock-up agreements as contemplated by the Merger Agreement. Ninety days after
the Effective Time, approximately 2,568,734 shares of the Restricted Stock
will become eligible for sale. One hundred eighty days after the Effective
Time, approximately 2,568,734 shares of Restricted Stock will become eligible
for sale. Two hundred forty days after the Effective Time, approximately
2,568,734 shares of the Restricted Stock will be eligible for sale. One year
after the Effective Time all of the Restricted Stock will be eligible for
sale.
 
  Holders of such warrants and options are likely to exercise them when, in
all likelihood, the Combined Company could obtain additional capital on terms
more favorable than those provided by warrants and options. Further, while
these warrants and options are outstanding, the Combined Company's ability to
obtain additional financing on favorable terms may be adversely affected. The
holders of the Unit Purchase Options and stockholders have certain demand and
"piggy-back" registration rights with respect to their securities. Exercise of
such rights could involved substantial expense to the Combined Company. See
"Principal Stockholders" and "Terms of the Merger--Discovery Stock Options and
Warrants".
 
  No prediction can be made as to the effect, if any, that sales of shares of
the Combined Company's Common Stock or the availability of such shares for
sale will have on the market prices that may be quoted from time to time on
the Nasdaq SmallCap Market. Nevertheless, the possibility that substantial
amounts of the Combined Company's Common Stock may be sold in the public
market may adversely effect the prevailing market prices for the Combined
Company's Common Stock and could impair the Combined Company's ability to
raise capital in the future through the sale of equity securities. Actual
sales or the prospect of future sales of shares of the Combined Company's
Common Stock under Rule 144 or otherwise may have a depressive effect upon the
price of the Combined Company's Common Stock and the market therefor.
 
 Antitakeover Effects of Provisions of the Certificate of Incorporation and
 Delaware Law
 
  Upon consummation of the Merger, the Combined Company's Certificate of
Incorporation, as amended, will authorize the issuance of up to 10,000,000
shares of preferred stock, of which 2,200,256 shares will be outstanding and
220,026 shares will be reserved for issuance upon the exercise of warrants.
The Board of
 
                                      28

Directors of the Combined Company will have the authority to fix and determine
the relative rights and preferences of preferred shares, as well as the
authority to issue such shares, without further stockholder approval. As a
result, the Board of Directors of the Combined Company could authorize the
issuance of a series of preferred stock which would grant to holders the
preferred right to the assets of the Combined Company upon liquidation, the
right to receive dividend coupons before dividends would be declared to Common
stockholders, and the right to the redemption of such shares, together with a
premium, prior to the redemption of the Combined Company's Common Stock.
Common stockholders have no redemption rights. In addition, the Board could
issue large blocks of preferred stock to fend against unwanted tender offers
or hostile takeovers without further stockholder approval.
 
  The Combined Company will be subject to Section 203 of the DGCL which,
subject to certain exceptions, prohibits a Delaware corporation from engaging
in any business combination with any interested stockholder for a period of
three years following the date that such stockholder became an interested
stockholder. In general, Section 203 defines an interested stockholder as any
entity or person beneficially owning 15% or more of the outstanding voting
stock of the corporation and any entity or person affiliated with or
controlling or controlled by such entity or person. The foregoing provisions
could have the effect of discouraging others from making tender offers for the
Combined Company's shares and, as a consequence, they also may inhibit
fluctuations in the market price of the Combined Company's shares that could
result from actual or rumored takeover attempts. Such provisions also may have
the effect of preventing changes in the management of the Combined Company.
 
 Dividends Unlikely
 
  Ansan and Discovery have never paid cash dividends on their capital stock
and the Combined Company does not anticipate paying any cash dividends for the
foreseeable future.
 
 Possible Restrictions on Market-Making Activities in the Combined Company's
 Securities
 
  D.H. Blair Investment Banking Corp., Inc. ("D.H. Blair") is currently making
a market in Ansan's securities. Regulation M ("Reg M") promulgated under the
Exchange Act, prohibits D.H. Blair from engaging in any market making
activities with regard to Ansan's securities for the period beginning from
five business days (or such other applicable period as Reg M may provide)
prior to any solicitation by D.H. Blair of the exercise of Ansan's outstanding
warrants until the completion of D.H. Blair's participation in such
distribution (under the meaning of Reg M). As a result, D.H. Blair may be
unable to provide a market for the Combined Company's securities during
certain periods while such warrants are exercisable.
 
 Possible Adverse Effect on Liquidity of the Combined Company's Securities Due
 to the Investigation of D.H. Blair and D.H. Blair & Co., Inc. by the
 Commission and Recent Settlement by D.H. Blair & Co., Inc. with the NASD
 
  The Commission is conducting an investigation concerning various business
activities of D.H. Blair and D.H. Blair & Co., Inc. ("D.H. Blair & Co."), the
principal market maker in Ansan's securities. The investigation appears to be
broad in scope, involving numerous aspects of D.H. Blair & Co.'s compliance
with the Federal securities laws and compliance with the Federal securities
laws by issuers whose securities were underwritten by D.H. Blair or D.H. Blair
& Co., or in which D.H. Blair or D.H. Blair & Co. made over-the-counter
markets, persons associated with D.H. Blair or D.H. Blair & Co. or such
issuers and other persons. Ansan has been advised by D.H. Blair that the
investigation has been ongoing since at least 1989 and that it is cooperating
with the investigation. D.H. Blair cannot predict whether this investigation
will ever result in any type of formal enforcement action against D.H. Blair
or D.H. Blair & Co. In July 1997, Blair & Co., its Chief Executive Officer and
its head trader consented, without admitting or denying any violations, to a
settlement with the NASD District Business Conduct Committee for District No.
10 to resolve allegations of NASD rule and securities law violations in
connection with mark-up and pricing practices and adequacy of disclosures to
customers regarding market-making activities of D.H. Blair & Co. in connection
with certain securities issues during the period from
 
                                      29

June 1993 through May 1995 where D.H. Blair & Co. was the primary selling
group member. NASD alleged the firm failed to accurately calculate the
contemporaneous cost of securities in instances where the firm dominated and
controlled after-market trading, thereby causing the firm to charge its
customers excessive mark-ups. NASD also alleged the firm did not make adequate
disclosure to customers about its market-making activities in two issues. As
part of the settlement, D.H. Blair & Co. has consented to a censure and has
agreed to pay a $2 million fine, make $2.4 million in restitution to retail
customers, employ an independent consultant for two years to review and make
recommendations to strengthen the firm's compliance procedures, and has
undertaken for 12 months not to sell to its retail customers (excluding banks
and other institutional investors) more than 60% of the total securities sold
in any securities offering in which it participates as an underwriter or
selling group member. The Chief Executive Officer of D.H. Blair & Co. has
agreed to settle failure to supervise charges by consenting to a censure, the
imposition of a $225,000 fine and a 60-day suspension from associating with
any NASD member firm and to take a requalification examination. The firm's
head trader has agreed to settle charges against him by consenting to a
censure, the imposition of a $300,000 fine and a 90-day suspension from
associating with any member firm and has undertaken to take certain
requalification examinations.
 
  Ansan is unable to predict whether D.H. Blair & Co.'s settlement with the
NASD or any unfavorable resolution of the Commission's investigation will have
any effect on such firm's ability to make a market in the Combined Company's
securities and, if so, whether the liquidity or price of the Combined
Company's securities would be adversely affected.
 
                                      30

                              VOTING AND PROXIES
 
DATE, TIME AND PLACE OF ANSAN SPECIAL MEETING
   
  The Ansan Special Meeting will be held at Ansan's principal executive
offices, Suite 435, 400 Oyster Point Boulevard, South San Francisco,
California 94080, on November 24, 1997 at 10:00 a.m., local time.     
 
RECORD DATE AND OUTSTANDING SHARES
 
 Ansan
   
  Stockholders of record of Ansan at the close of business on October 22, 1997
(the "Ansan Record Date") are entitled to notice of and to vote at the Ansan
Special Meeting. At the Ansan Record Date, approximately 11 Ansan stockholders
were holders of record of Ansan Common Stock (in addition to approximately 600
beneficial owners of Ansan Common Stock held in street name) and approximately
2,851,954 shares of Ansan Common Stock were issued and outstanding. At the
Ansan Record Date, Discovery was the sole holder of record of Ansan Series A
Preferred Stock and 13,000 shares of Ansan Series A Preferred Stock were
issued and outstanding. Except for the stockholders identified under
"Principal Stockholders" there were no persons known to the management of
Ansan to be the beneficial owners of more than 5% of the outstanding Ansan
Common Stock or Ansan Series A Preferred Stock.     
 
 Discovery
   
  Stockholders of record of Discovery at the close of business on October 22,
1997 (the "Discovery Record Date") are entitled to act by written current
pursuant to the Discovery Written Consent. At the Discovery Record Date, there
were approximately 255 stockholders of Discovery of record, and approximately
6,747,256 shares of Discovery Common Stock and 2,200,256 shares of Discovery
Series A Preferred Stock were issued and outstanding. Except for the
stockholders identified under "Principal Stockholders", there were no persons
known to the management of Discovery to be the beneficial owners of more than
5% of the outstanding Discovery Common Stock or Discovery Series A Preferred
Stock.     
 
VOTING OF PROXIES
 
  All properly executed proxies that are not revoked will be voted at the
Ansan Special Meeting in accordance with the instructions contained therein.
Proxies containing no instructions regarding the proposals specified in the
form of proxy will be voted for approval of the matters put before the Ansan
Special Meeting and outlined in this Prospectus/Proxy Statement. If any other
matters are properly brought before the Ansan Special Meeting and submitted to
a vote, all proxies will be voted in accordance with the judgment of the
persons voting the proxies. Any stockholder signing a proxy has the power to
revoke it prior to the Ansan Special Meeting or at the Ansan Special Meeting
prior to the vote pursuant to the proxy. A proxy may be revoked by a
subsequent proxy that is signed by the stockholder and presented at the Ansan
Special Meeting or by attendance at the Ansan Special Meeting and casting a
contrary vote.
 
VOTE REQUIRED
 
  Under the DGCL, approval of the Merger Proposal requires the affirmative
vote or written consents of the holders of a majority of the voting power of
each of the Ansan Stock and the Discovery Stock. Pursuant to the Titan Voting
Agreement, Titan, which as of August 31, 1997 held approximately 32% of the
outstanding Ansan Stock on an as-converted basis, has agreed to vote such
stock in favor of the Merger Proposal. Stockholders holding approximately
23.2% of the votes of the outstanding shares of Discovery Stock have executed
the Discovery Voting Agreements which grant a proxy to representatives of
Ansan to consent to the Merger pursuant to the Discovery Written Consent. See
"Terms of the Merger--Voting Agreements." Consummation of the Merger is
subject to approval of the Ansan stockholders, the Discovery stockholders and
of a number of other conditions. See "Terms of the Merger--Conditions to the
Merger."
 
  Approval of other matters at the Ansan Special Meeting will require
approvals as described under the heading "Additional Matters for Consideration
of Ansan Stockholders."
 
                                      31

SOLICITATION OF PROXIES AND EXPENSES
 
  Each of Ansan and Discovery will bear the cost of the solicitation of
proxies or written consents from their respective stockholders. In addition to
solicitation by mail, the directors, officers and employees of Ansan and
Discovery may solicit proxies or written consents from stockholders by
telephone, telegram, letter or in person. Arrangements will also be made with
brokerage houses and other custodians, nominees and fiduciaries for the
forwarding of solicitation material to the beneficial owners of stock held of
record by Ansan's stockholders, and Ansan will reimburse such custodians,
nominees and fiduciaries for reasonable out-of-pocket expenses incurred by
them in connection therewith.
 
                      THE MERGER AND RELATED TRANSACTIONS
 
THIS IS PROPOSAL NO. 1 TO BE CONSIDERED AND VOTED ON BY ANSAN STOCKHOLDERS AND
THE ONLY PROPOSAL TO BE CONSIDERED AND CONSENTED TO BY DISCOVERY STOCKHOLDERS.
 
  The following discussion summarizes the proposed Merger and related
transactions, and is a summary of all material terms but is not a complete
statement of all provisions of the Merger Agreement and related transactions.
Detailed terms of and conditions to the Merger and certain related
transactions are contained in the Merger Agreement, a conformed copy of which
is attached to this Prospectus/Proxy Statement as Annex C. Reference is also
made to the form of Certificate of Merger attached to this Prospectus/Proxy
Statement as Annex D. Statements made in this Prospectus/Proxy Statement with
respect to the terms of the Merger and such related transactions are qualified
in their entirety by reference to the more detailed information set forth in
the Merger Agreement.
 
BACKGROUND TO THE MERGER
 
  Ansan has been engaging in pharmaceutical research and development
activities since its inception. As a consequence of such activities, Ansan has
expended significant funds without receipt of replenishing revenues.
 
  Ansan's regularly prepared balance sheet dated December 31, 1996 indicated
total assets of $1,923,474, which was below the required threshold for
continued listing on the Nasdaq SmallCap Market. On April 22, 1997, Ansan
received a letter from the NASD indicating that Ansan was no longer in
compliance with the continued inclusion standard for total assets. In the
meantime, Ansan and Titan, which currently holds 32% of Ansan Stock, had, on
March 21, 1997 entered into an agreement for financing pursuant to which Titan
advanced Ansan $1,000,000 in return for a debenture (the "Debenture"). Titan
had until June 21, 1997 to convert the Debenture to equity and to invest an
additional $1,000,000 in Ansan. This financing provided Ansan with operating
capital to fund Ansan's operations and was anticipated by Ansan to provide
additional operating capital. All debt due to Titan from Ansan will be repaid
by Ansan concurrently with the closing of the Merger. See "Information
Concerning Ansan--Relationship with Titan Pharmaceuticals, Inc."
 
  Ansan responded to the NASD inquiries by filing its March 31, 1997 report on
Form 10-Q which indicated that it was in compliance with the NASD's continued
inclusion standard for total assets but also indicated that Ansan was no
longer in compliance with the NASD's $1,000,000 capital and surplus standard.
As a consequence, the NASD advised Ansan that they planned to de-list Ansan
from the Nasdaq SmallCap Market.
 
  On July 16, 1997, Ansan and Discovery executed the Series A Purchase
Agreement pursuant to which Discovery purchased 13,000 shares of Series A
Preferred Stock of Ansan for a purchase price of $1,300,000 (the "Purchase
Price"). The Series A Purchase Agreement was negotiated with the objective of
bringing Ansan into compliance with the listing standards for the Nasdaq
SmallCap Market pending consummation of the Merger. Ansan and Discovery
concurrently executed the Merger Agreement.

                                      32

  The NASD Listing Qualification Panel held a hearing concerning Ansan on July
17, 1997 at which time the NASD granted Ansan a temporary exemption
conditioned upon Ansan filing a certain balance sheet demonstrating compliance
with the Nasdaq listing requirements on or before July 31, 1997 and upon Ansan
providing monthly internal balance sheets to the NASD evidencing compliance
with all criteria necessary for continued listing on the Nasdaq. The initial
filing was accomplished prior to July 31, 1997. Additionally, Ansan must make
certain filings with the Commission no later than November 30, 1997
evidencing, among certain related financial matters, completion of the Merger.
In the event that Ansan fails to comply with any of the NASD requirements, the
Ansan Common Stock will be immediately delisted from the Nasdaq SmallCap
Market.
 
  Pursuant to both the Series A Purchase Agreement and the Merger Agreement,
Ansan is generally restricted from using the proceeds from the sale of the
Ansan Series A Preferred Stock other than pursuant to an operating budget
specified in both the Series A Purchase Agreement and the Merger Agreement
(the "Operating Budget").
 
  The Certificate of Designation of the Ansan Series A Preferred Stock
provides that such stock shall be convertible into shares of Ansan Common
Stock at a conversion rate equal to the amount determined by dividing $100.00
by the average closing bid price of the Ansan Common Stock over the 30 trading
days immediately preceding the issuance of the Ansan Series A Preferred Stock,
subject to adjustment under certain circumstances (the "Conversion Rate"). The
Conversion Rate is currently $1.40.
 
  The Conversion Rate shall automatically reset upon the occurrence of any of
the following events: (a) the Ansan Common Stock ceasing to be quoted on the
Nasdaq SmallCap Market, (b) the failure of Ansan to attain, prior to September
1, 1997, a successful conclusion to the NASD delisting procedure formerly
pending against it, or (c) non-consummation of the Merger on or prior to
December 31, 1997 for any reason other than the failure of the Discovery
stockholders to approve the Merger, actual fraud by Discovery in connection
with any representation, warranty or covenant made by Discovery in the Merger
Agreement, or termination of the Merger Agreement solely due to a Discovery
Breach. "Discovery Breach" is defined as any of: (w) a failure by Discovery to
provide documents reasonably necessary for any filing by Ansan with the
Commission, (x) a failure by Discovery to maintain working capital (on a non-
consolidated basis) of at least $5,000,000, (y) a material breach by Discovery
of certain representations and warranties in the Merger Agreement, or (z) the
loss of tax-free reorganization status for the Merger solely due to an act or
omission of Discovery (a "Reset Event"). Upon the occurrence of a Reset Event,
the Conversion Rate shall be reset to that rate which will permit the holders
of the Series A Preferred Stock to convert such stock into 51% of the Ansan
Common Stock (excluding Common Stock underlying Ansan's Class A Warrants and
Class B Warrants and comprising components of certain Underwriter Units that
include such warrants). If a Reset Event occurs, the holders of the Ansan
Series A Preferred Stock (currently being Discovery) would likely obtain
voting control of Ansan. Pursuant to the Certificate of Designation relating
to the Ansan Series A Preferred Stock, Ansan has an option to redeem all the
shares of Series A Preferred Stock during a "Redemption Period." The
Redemption Period is either: (i) the thirty day period beginning on the date
on which a Reset Event occurs (the "Reset Date"), if the Reset Date is before
August 31, 1997 or (ii) a sixty day period beginning on the Reset Date, if the
Reset Date is after August 31, 1997.
 
  Any material failure of Ansan to perform in accordance with the Operating
Budget provides Discovery with the right to unilaterally terminate the Merger
Agreement. This Discovery termination would, in turn, constitute a Reset Event
and would lead to the consequences described above.
 
INTERESTS OF CERTAIN PERSONS

  In considering the recommendations of the Ansan Board and the Discovery
Board with respect to the Merger Proposal, stockholders of Ansan and Discovery
should be aware that certain officers and directors of Ansan and Discovery
have interests in the Merger in addition to those of stockholders generally,
including those referred to below. The Ansan Board and the Discovery Board
were aware of these interests and considered them in their respective
deliberations concerning the Merger.
 
  Should the Merger Proposal be approved by the stockholders of each
respective company and the Merger be consummated, the Titan Sublicense
Agreement will become effective and Ansan will sublicense certain technology
to Titan in exchange for the cancellation of all Ansan Stock owned by Titan
and a 2% royalty on sales of licensed products. Titan currently holds 32% of
the outstanding Ansan Stock on an as-converted basis.

                                      33

  Louis R. Bucalo, M.D., who is a director and the Chairman of the Board of
Ansan, is also a director and the President and Chief Executive Officer of
Titan.
 
  Lindsay A. Rosenwald, M.D., a director of Ansan, is also (through RAQ, LLC
of which he is the President) the owner of 2,574,125 shares of Discovery
Common Stock, representing approximately 17% of the aggregate voting power of
the outstanding Discovery Stock. Dr. Rosenwald also serves as a director of
Titan. In addition, Dr. Rosenwald is the Chairman of the Board of Paramount
Capital. Paramount Capital served as placement agent for Discovery in
Discovery's private equity placement during June through November 1996 and in
Titan's private equity placement during 1993.
 
  Steve H. Kanzer C.P.A., Esq. is the Chairman of Discovery. He is also a
Senior Managing Director of Paramount Capital and Senior Managing Director--
Head of Venture Capital of Paramount Investments.
 
  During deliberations and voting of the Ansan Board on approval of the Merger
Proposal, both Dr. Bucalo and Dr. Rosenwald abstained and did not participate
therein. During deliberation and voting of the Discovery Board, Mr. Kanzer
abstained and did not participate therein.
 
  Except as noted above, no officer or director of Ansan or Discovery has any
interest in the Merger Proposal that is in addition to his interest as a
stockholder of Ansan or Discovery.
 
JOINT REASONS FOR THE MERGER
 
  The Ansan Board and the Discovery Board believe that by combining the
operations of Ansan and Discovery, the following joint benefits can be
obtained:
 
  .  Benefits arising from the commonality of business focus and industry
     positioning shared by, and the combination of the assets, operations and
     prospects of, Ansan and Discovery. Each of Ansan and Discovery has, as
     its business focus, the development of drugs based on adding value in
     clinical development rather than early stage research. Each of the Ansan
     Board and the Discovery Board believes that there are strategic and
     regulatory synergies than can be realized from the combination of the
     drug development businesses of the two companies.
 
  .  The more robust pipeline of drug products the Combined Company will have
     in development and the resulting increased likelihood of success as a
     drug development company. Having a broader base of programs in
     development may mitigate some of the risks inherent in drug development.
     The respective Boards believe that risk diversification through the
     combination of Ansan's and Discovery's product pipelines will be
     beneficial to stockholders of the Combined Company.
 
  .  Benefits relating to the combination of corporate infrastructure,
     management and financial resources available to the operations of the
     Combined Company. The respective Boards anticipate that economies of
     scale and operational efficiencies are likely to result from the
     combination of Ansan and Discovery.
 
  Ansan and Discovery have each identified additional reasons for the Merger,
which are discussed below. Such reasons, together with the joint reasons
described above, constitute all of the material factors considered by the
respective Boards of Ansan and Discovery in connection with the Merger. Each
Board of Directors has recognized that the potential benefits of the Merger
may not be realized. See "Risk Factors."
 
ANSAN'S REASONS FOR THE MERGER
 
  In addition to the anticipated joint benefits described above, the Ansan
Board believes that the following are additional reasons the Merger will be
beneficial to Ansan and its stockholders and for Ansan stockholders to vote
FOR the proposals set forth herein:
 
  .  Ansan's need to raise additional capital to pursue its drug development
     programs. The Ansan Board believed that cash resources available to
     Ansan were inadequate to advance Ansan's development plan.
 
  .  Titan's inability to provide such capital to Ansan. The Ansan Board
     noted that Titan did not exercise its option to acquire additional
     equity in Ansan by June 21, 1997 nor did Titan convert its existing debt
     to equity.

                                      34

  .  Ansan's desire to maintain Nasdaq SmallCap Market listing. See "The
     Merger and Related Transactions -- Background to the Merger". The Ansan
     Board believes that maintenance of such Nasdaq listing is important in
     maintaining an active market for Ansan's Common Stock.
 
  .  Ansan's inability to locate a suitable corporate partner within the
     timeframe of its capital requirements. The Ansan Board felt that Ansan's
     Pivanex(TM) program was viewed by potential corporate partners as being
     at too early a stage of development to elicit interest from a corporate
     partner within a time frame sufficient to allow Ansan to remain listed
     on Nasdaq and continue its development program.
 
  .  The relative difficulty faced by Ansan in obtaining alternative
     financing within the timeframe of its capital requirements given this
     developmental status, Ansan's small market capitalization and the lack
     of significant trading activity in Ansan Common Stock.
 
  .  The Ansan Board felt that there were benefits to be gained from the
     respective intellectual property portfolios of Ansan and Discovery.
 
  .  The observations and conclusions of the Ansan Board with respect to the
     prospects for a strategic business combination between Ansan and
     candidates other than Discovery as a consequence of the developmental
     status outlined above.
 
  .  The prospects for the long-term performance of the Ansan Common Stock in
     light of Ansan's inability to obtain alternative financing and the
     current expenditures of funds in Ansan's development program.
 
  The Ansan Board considered a number of factors relating to the Merger,
including the following:
 
  .  The terms and conditions of the Merger, including the amount and form of
     the consideration, which it believed to be the most favorable
     transaction possible with Discovery.
 
  .The tax-free status of the Merger and the accounting and financial impact
  of the Merger
 
  The Ansan Board also identified and considered a variety of potentially
negative factors in its deliberations concerning the Merger, including:
 
  .  The loss of certain product rights pursuant to the Titan Sublicense
     Agreement including the Pivanex(TM) program outlined above.
 
  .  The dilutive effect of the issuance of Ansan Common Stock to Discovery
     stockholders pursuant to the Merger.
 
  .  The substantial charges expected to be incurred including, but not
     limited to, legal, accounting, printing and fairness opinion costs and
     fees in connection with the Merger.
 
  .  The risk that the public market price of Ansan's Common Stock may be
     adversely affected by announcement of the Merger.
 
  .  The potential disruption of Ansan's business that might result from
     employee uncertainty and lack of focus following announcement of the
     Merger and during the integration of the operations of Ansan and
     Discovery.
 
  .  The possibility that the Merger might not be consummated, and the
     effects of the public announcement of the Merger on Ansan's ability to
     attract and retain key management and technical personnel and the
     progress of Ansan's development projects.
 
  .  The risk that other benefits sought to be achieved in the Merger will
     not be achieved.
 
  .  Other risks described under "Risk Factors".
 
  The Ansan Board believes that these risks are outweighed by the potential
benefits of the Merger.
 
  In view of the wide variety of factors considered in connection with its
evaluation of the Merger, the Ansan Board did not find it practicable to and
did not quantify or assign any relative weights to the factors considered
 
                                      35

in reaching its determination, although its individual members may have given
different weights to different factors. Consequentially, while the Ansan Board
did rely on the fairness opinion rendered to it by Dakin Securities, it also
considered a variety of other financial and non-financial factors in reaching
its conclusion that the Merger was in the best interests of Ansan
stockholders.
 
  At its July 14, 1997 Board meeting, the Ansan Board approved (by a 4-0 vote
with two members abstaining) the Merger Proposal and the transactions
contemplated thereby.
 
  ANSAN'S BOARD RECOMMENDS THAT THE ANSAN STOCKHOLDERS VOTE FOR THE MERGER
PROPOSAL.
 
DISCOVERY'S REASONS FOR THE MERGER
 
  The Discovery Board believes that the terms of the Merger are fair to, and
in the best interests of, Discovery and has approved (by a 6-0 vote, with one
member abstaining) the Merger Agreement and the related transactions. The
Discovery Board recommends that the Discovery stockholders consent to the
Merger. In addition to the anticipated joint benefits described above, the
Discovery Board believes the following are additional reasons the Merger will
be beneficial to Discovery and for the Discovery stockholders to consent to
the Merger:
 
  .  The opportunity presented by the Merger to achieve greater liquidity,
     and potentially stronger performance, of Discovery's Common Stock by
     securing a trading market for Discovery's securities. The Discovery
     Board believes that increased liquidity of Discovery's shares will
     result in the creation of a financially stronger company and provide a
     greater opportunity to raise capital which may be required for continued
     research and development programs.
 
  .  The ability to attain Nasdaq listing and profit from the greater
     liquidity likely to be realized on the Nasdaq SmallCap Market as
     compared to the OTC Electronic Bulletin Board (the only venue likely to
     be available for the trading of Discovery securities absent the Merger).
     As set forth above, the Discovery Board believes that greater liquidity
     (which a listing on Nasdaq provides) could potentially increase future
     financial, technological, research and development, and marketing
     opportunities for Discovery.
 
  .  The benefits to be gained from the acquisition of rights over technology
     owned or licensed by Ansan, such as Apafant and AN10, and the marketing
     of potential products stemming from such technology. The Discovery Board
     believes that such acquisitions will strengthen Discovery's competitive
     position, diversify risk and create cost savings.
 
  .  The revenues that may be realized from royalties paid to the Combined
     Company under the Titan Sublicense Agreement. Such revenues could
     contribute to improving the overall financial condition of Discovery.
 
  .  The benefits to be gained from the diversification of Discovery's
     product pipeline. The Discovery Board believes that such diversification
     could increase the likelihood of successful development of a future
     product or products.
 
  .  The benefits to be gained from the acquisition of and constructive
     sharing of Ansan's drug development and regulatory expertise. The
     Discovery Board believes that constructive sharing of Ansan's expertise
     in regulatory and product development areas could result in strategic
     advantages and cost savings for the Combined Company.
 
  .  The opportunity following the Merger to raise capital and complete
     stock-for-stock and other transactions more easily as a consequence of
     being a public company.
 
  The Discovery Board considered a number of factors relating to the Merger,
including the following:
 
  .  The judgment, advice and analyses of its management regarding the terms
     of the Merger, based in part on the business, financial, accounting and
     legal due diligence investigations performed with respect to Ansan.
     Pursuant to such advice, the Discovery Board believes that the Merger
     represents an opportunity to create a stronger company with a broader
     base of products under development which will enable Discovery to
     strengthen its competitive position in the industry.

                                      36

  .  Information concerning the financial condition, results of operations,
     prospects and businesses of Discovery and Ansan and the stock price
     performance of Ansan.
 
  .  The management challenges associated with successfully integrating
     Discovery and Ansan. The Discovery Board believes that such challenges
     are unlikely to pose significant difficulties since it is not
     anticipated that integration issues will bear meaningfully on the drug
     development process, which currently constitutes the principal activity
     of each of Discovery and Ansan and is likely to constitute the principal
     activity of the Combined Company for a number of years.
 
  .  The advice of counsel that the Merger should be treated as a tax-free
     organization.
 
  .  The Discovery Board's recognition that certain members of the Board have
     interests in the Merger that are in addition and not necessarily aligned
     with the interests in the Merger of holders of Discovery Stock, which
     interests were considered in connection with its approval of the Merger
     Agreement. Notwithstanding the foregoing, the Discovery Board believes,
     pursuant to its examination of financial and nonfinancial matters, that
     the Merger is in the best interests of Discovery. Furthermore, the sole
     Discovery director with a potential conflict of interest recused himself
     from the vote of the Discovery Board approving the Merger.
 
  The Discovery Board also identified and considered a variety of potentially
negative factors in its deliberations concerning the Merger, including:
 
  .  The possibility that Ansan will be delisted from the Nasdaq SmallCap
     Market and that in such event the goal of obtaining the liquidity
     associated with listing on such market would not be achieved.
 
  .  The possibility that the Merger might not be consummated and that in
     such event the interim investment represented by the Ansan Series A
     Preferred Stock would represent ownership of a large portion of a
     company that would not necessarily be an attractive investment candidate
     absent the Merger. The Certificate of Designation for the Series A
     Preferred Stock provides for a redemption of shares, at its option, by
     Ansan if certain conditions (including the failure to consummate the
     Merger for reasons attributable to Discovery) occur. In the event the
     Merger does not occur the Discovery Board believes that Ansan would seek
     to redeem the Ansan Series A Preferred Stock, although there can be no
     assurance that Ansan would be able to do so.
 
  .  The risk that, despite the efforts of the Combined Company, key
     technical and management personnel may not remain employed by the
     Combined Company. The Discovery Board believes that if the Combined
     Company remains as a Nasdaq-listed company and provides a sustainable
     business, the Combined Company will have the opportunity to attract new
     personnel and compete with respect to compensation and incentives.
 
  .  The possibility that the Combined Company will not be able to pursue all
     of Discovery's products simultaneously or that one or more such products
     may be required to be divested.
 
  .  The considerable transaction costs expected to be incurred in connection
     with the Merger, without the ability to recoup expenses in the event
     that the Merger is not consummated.
 
  .  The likelihood that the rate at which the Combined Company will expend
     cash for day-to-day operations will increase, perhaps substantially. The
     Discovery Board believes that the resources of the Combined Company,
     together with the proceeds raised through future financing efforts, will
     be sufficient to meet the Combined Company's expected cash needs.
 
  .  The risk that Ansan's and Discovery's operation will suffer as a
     consequence of management being distracted as it attends to matters
     related to the Merger.
 
  .  The risk that other benefits sought in the Merger may not be achieved.
 
  .  Other risks described under "Risk Factors".
 
  The Discovery Board believes that these risks are outweighed by the
potential benefits of the Merger.
 
                                      37

  As outlined above, the Board of Directors of Discovery took into account a
variety of financial and nonfinancial considerations in reaching its decision
to approve the Merger. Although the Board relied on the Sands Brothers
fairness opinion as an indication of the fairness of the Exchange Ratio, from
a financial point of view, to Discovery stockholders and did not make an
independent determination of financial fairness, the Board independently
reviewed and considered, among other things, the financial position, cash
position, cash burn rate and projected operating budget for Ansan in reaching
its determination that the Merger is in the best interests of Discovery.
 
  In view of the wide variety of factors considered in connection with its
evaluations of the Merger, the Discovery Board did not find it practicable to
and did not quantify or assign any relative weights to the factors considered
in reaching its determination, although its individual members may have given
different weights to different factors.
 
  At its July 15, 1997 board meeting, the Discovery Board approved the Merger,
with one director, Steve H. Kanzer, C.P.A., Esq., abstaining from voting and
all remaining directors voting in favor thereof. As discussed under "Risk
Factors--Certain Interlocking Relationships; Potential Conflicts of Interest"
and "The Merger and Related Transactions-- Interests of Certain Persons", Mr.
Kanzer is also a Senior Managing Director of Paramount Capital and Senior
Managing Director--Head of Venture Capital of Paramount Capital. Lindsay A.
Rosenwald, M.D., the Chairman and Chief Executive Officer of Paramount
Capital, is also a member of the Board of Directors of Ansan and a member of
the Board of Directors of Titan.
 
  THE DISCOVERY BOARD OF DIRECTORS RECOMMENDS THAT THE HOLDERS OF DISCOVERY
COMMON STOCK VOTE FOR APPROVAL AND ADOPTION OF THE MERGER AGREEMENT.
 
                   MATERIAL CONTACTS AND BOARD DELIBERATIONS

  During the Spring of 1997, Ansan's management became aware that Ansan
required a further injection of capital to support its drug development
programs and operations. Ansan's management was also concerned that Titan
might not exercise its option to invest a further $1 million in late June (See
"The Merger and Related Transactions--Background to the Merger"), that
alternative sources of equity capital were unlikely to be available due to the
unfavorable financing climate for small development-stage biotechnology
companies, and that debt financing was inappropriate for a company lacking the
prospect of near-term product revenues. Accordingly, Ansan's management
determined that Ansan should explore potential business combinations with
other corporations whose operations would be complementary to Ansan.
 
  On May 6, 1997 Mr. Shalson contacted James S. Kuo, M.D., President and Chief
Executive Officer of Discovery, and the parties engaged in discussions with
respect to Discovery's business and activities.
 
  At an Ansan Board of Directors meeting held on May 8, 1997, Mr. Shalson
advised the Ansan Board of his preliminary discussions with Discovery. At that
time, the Ansan Board determined that Mr. Shalson should continue exploring
possible strategic business combinations with Discovery.
 
  On May 14, 1997 Mr. Shalson and James Ahlers, Ansan's Director of Finance
and Operations, met with Dr. Kuo and Evan Myrianthopoulos, Chief Operating
Officer of Discovery, to engage in further discussions about the respective
businesses of Ansan and Discovery and to explore the possibility of a business
combination between the two companies. Over the course of the next several
weeks, Messers. Shalson, Ahlers, Kuo and Myrianthopoulos exchanged information
on the technologies, product development programs, budgets and financial
condition of each of Ansan and Discovery and all other material details of
their respective operations necessary. As negotiations advanced, the depth of
this mutual disclosure also advanced.
 
                                      38

  From mid-May until mid-June 1997, Ansan engaged in discussions with a
financial intermediary about a possible business combination or similar
transaction with another prospective partner developing related technology.
After providing certain corporate information to the financial intermediary,
Ansan attempted to pursue discussions as to a potential transaction. However,
Ansan did not receive any further expression of interest from the prospective
partner. Ansan was unable to determine the basis for this lack of interest.
 
  At approximately the same time as the foregoing, Ansan attempted to retain a
financial representative to locate other potential corporate partners or
alternative transactions. Ansan's efforts failed due to the financial
difficulties being experienced by it.
 
  Finally, at about the same time as the foregoing, Ansan attempted to
negotiate a potential transaction with a subsidiary corporation of Titan. This
subsidiary corporation declined to consider a transaction with Ansan due to
Ansan's pre-existing warrant structure.
 
  Between May 14, 1997 and May 29, 1997 there were several telephone
conversations between Mr. Shalson and Dr. Kuo regarding a possible business
combination between Ansan and Discovery. A meeting between Mr. Shalson and Dr.
Kuo to advance the prospects of a business combination between the respective
companies was scheduled for June 3, 1997.
 
  On June 2, 1997 an Ansan Board of Directors meeting was held, at which time
Mr. Shalson updated a special committee of disinterested directors of the
Ansan Board (the "Ansan Committee") with respect to potential Ansan financing
options and Ansan's discussions with Discovery. At that time, the Ansan
Committee authorized the further exploration of a possible merger between
Ansan and Discovery.
 
  On June 3, 1997 Dr. Kuo and Mr. Myrianthopoulos met with Mr. Shalson at the
offices of Discovery. At that time each of Ansan and Discovery presented their
respective drug development programs to the other.
 
  On June 18, 1997 further discussions were held by telephone conference
between Ansan and Discovery. At that time, it was determined that the
discussion should be expanded to include representatives of Titan because
Titan owned approximately 43% of the then-outstanding shares of Ansan Stock.
 
  On June 19, 1997 a conference call was held between the respective officers
of Ansan, Discovery, and Titan. During this conference call, Discovery
presented a proposal to merge Discovery into Ansan. This proposal was
unacceptable to Titan because Titan did not want to become a less than 10%
stockholder in a development-stage pharmaceutical company as this was
inconsistent with its business strategy. Ansan responded with a proposal to
exchange Ansan technology rights with Titan for Ansan stock (i.e. the Titan
sublicense) and then merge the remainder of Ansan with Discovery. An agreement
was reached to exchange preliminary due diligence materials in order to effect
further discussions in respect of the proposals.
 
  On June 20, 1997 Ansan and Discovery signed a confidentiality agreement and
each distributed due diligence materials to the other. Additionally, on June
20, 1997 Mr. Shalson and Mr. Ahlers met with Sunil Bhonsle and Robert Farrell,
the Chief Operating Officer and Chief Financial Officer of Titan,
respectively, during which time the Titan component of the overall proposal
was determined through the process of negotiation between the respective
parties.
 
  On June 21, 1997 Titan did not convert the Debenture into equity and did not
make an additional equity investment into Ansan.
 
  Further due diligence reviews occurred on June 24 and 25, 1997. At that
time, on-site inspections were arranged and an updated merger proposal was
received by Ansan from Discovery.
 
  On June 27, 1997 Dr. Kuo and Mr. Myrianthopoulos visited Ansan. During this
meeting the parties reviewed Ansan's drug development programs and budgets in
detail. Follow-up discussions were held with the respective officers of Titan
pertaining to the Titan Sublicense component of the transaction.
 
                                      39

  On July 2, 1997 Thomas Alessi, Ph.D., Senior Director of Regulatory Affairs
and Quality Assurance of Ansan visited ATI and conducted due diligence related
to ATI.
 
  On July 3, 1997 Dr. Alessi visited Discovery and conducted due diligence
related to Discovery.
 
  On July 3, 1997 Ansan held a meeting of the Ansan Committee at which time
Mr. Shalson reviewed with the Committee the latest proposal from Discovery and
the status of negotiations with Discovery and Titan. The Ansan Committee
directed Ansan management to continue negotiations with Discovery and Titan.
 
  From July 7, 1997 to July 9, 1997 further discussion occurred among officers
of Ansan, Discovery, Titan, and their respective professional advisors with
respect to the terms of a potential merger. On July 10, 1997 Ansan held a
Committee meeting at which time Mr. Shalson reviewed with the Ansan Committee
the status of negotiations with Discovery and Titan. The Ansan Committee
directed Ansan management to continue negotiations with Discovery and Titan.
 
  On July 12, 1997 an Ansan Committee meeting was held at which time Mr.
Shalson reviewed with the Ansan Committee the status of negotiations with
Discovery and Titan and issues relating to the fairness of the transaction.
The Ansan Committee directed Ansan management to continue negotiations with
Discovery and Titan on substantially the terms discussed.
 
  On July 13, 1997 Ansan held a conference call with Titan to discuss the
terms of the Titan sublicensing arrangement. On July 14, 1997 Ansan and its
counsel continued its negotiations with Discovery and their respective
counsel. Further, on July 14, 1997 Ansan held a Committee meeting at which
time Mr. Shalson reviewed with the Committee the terms of the final agreements
with Discovery and Titan. Additional discussions were held with respect to the
fairness of the proposed transactions. At this time, the full Ansan Board
(Drs. Bucalo and Rosenwald abstaining) approved the transactions and
authorized management to execute the relevant agreements on the basis that the
proposed transactions were in the best interests of Ansan's stockholders and
as Discovery was the only party with whom Ansan had been able to advance and
conclude negotiations. Additionally, it was felt that the terms of the Titan
Sublicense Agreement were both necessary to conclude the Merger with Discovery
and in the best interests of Ansan's stockholders as a result of the
associated repurchase of Ansan Stock held by Titan.
 
  On July 15, 1997, Discovery held a Board of Directors meeting at which time
Mr. Kanzer reviewed the terms of the final agreements relating to the Merger
and the Board of Directors approved (by a 6-0 vote, with Mr. Kanzer
abstaining) the Merger and related transactions.
 
  On July 16, 1997, the parties thereto executed the Merger Agreement and
related documents. On July 18, 1997 Ansan and Titan issued a joint press
release announcing the Merger.
 
                                      40

                              FINANCIAL ADVISORS
 
ANSAN
 
  Ansan has retained Dakin Securities to act as its financial advisor in
connection with the fairness of the Merger, from a financial point of view, to
the Ansan stockholders. No instructions or limitations were given to or
imposed upon Dakin Securities in connection with its opinion, nor were any
limitations imposed upon the scope of Dakin Securities' investigation.
 
  Dakin Securities has delivered to the Board of Directors of Ansan its
written opinion, dated July 16, 1997, the complete text of which is set forth
as Annex A to this Prospectus/Proxy Statement. Ansan stockholders are urged to
read such opinion carefully and in its entirety for a description of the
procedures followed, the factors considered and the assumptions made by Dakin
Securities. In rendering its opinion, Dakin Securities relied, without
independent verification, upon the accuracy and completeness of the financial
and other information reviewed by them for purposes of its opinion. Ansan's
obligation to consummate the Merger is subject to its receipt from Dakin
Securities of a confirmation of its opinion at the time the Merger is to be
consummated.
 
  For Dakin Securities' above-described services to Ansan in connection with
the Merger, Ansan has agreed to pay Dakin Securities a fee of $75,000 (of
which a retainer of $25,000 has been paid, $25,000 is payable concurrently
with the filing of the Form S-4, and $25,000 is payable upon the consummation
of the Merger). Ansan has also agreed to reimburse Dakin Securities for
certain out-of-pocket expenses and to indemnify Dakin Securities against
certain liabilities, including liabilities under the Federal securities laws,
relating to or arising out of services performed by Dakin Securities as
financial advisor to Ansan.
 
  Dakin Securities is an investment banking firm. As part of its investment
banking business, Dakin Securities is continually engaged in the valuation of
businesses and their securities in connection with mergers and acquisitions,
underwritings, secondary distributions of securities, private placements and
valuations for estate, corporate or other purposes. Ansan decided to retain
Dakin Securities based on its experience as a financial advisor in mergers and
acquisitions, especially those involving life sciences companies.
 
OPINION OF ANSAN'S FINANCIAL ADVISOR
 
  Ansan retained Dakin Securities to act as its financial advisor in
connection with the Merger. Dakin Securities was selected by the Board of
Directors of Ansan to act as Ansan's financial advisor based on Dakin
Securities' qualifications and expertise, particularly in small capitalization
life sciences companies.
 
  Dakin Securities rendered an oral opinion to the Board of Directors of Ansan
at its meeting on July 16, 1997, which it subsequently confirmed in a written
opinion dated such date, that based upon and subject to the assumptions,
limitations and qualifications set forth in its opinion letter, the Exchange
Ratio was fair to the stockholders of Ansan Common Stock, from a financial
point of view.
 
  THE FULL TEXT OF THE OPINION OF DAKIN SECURITIES DATED JULY 16, 1997 IS
ATTACHED TO THIS PROSPECTUS/PROXY STATEMENT AS ANNEX A. ANSAN STOCKHOLDERS ARE
URGED TO READ DAKIN SECURITIES' OPINION CAREFULLY AND IN ITS ENTIRETY FOR A
DESCRIPTION OF THE ASSUMPTIONS MADE, PROCEDURES FOLLOWED AND OTHER MATTERS
CONSIDERED AND THE LIMITS OF DAKIN SECURITIES' REVIEW.
 
  Dakin Securities' opinion was prepared for the Board of Directors of Ansan
and is directed only to the fairness of the Exchange Ratio to stockholders of
Ansan from a financial point of view and does not constitute a recommendation
to any stockholder of Ansan as to how such stockholder should vote at the
Ansan Special Meeting nor does it constitute an opinion as to the price at
which Ansan Common Stock will actually trade at any time. Dakin Securities was
not requested to and did not make any recommendation to the Board of Directors
of Ansan as to the form or amount of the consideration to be received by
stockholders of Ansan in the Merger, which was determined through arm's-length
negotiations between the parties prior to the formal engagement of
 
                                      41

Dakin Securities. No restrictions or limitations were imposed by Ansan upon
Dakin Securities with respect to the investigations made or the procedures
followed by Dakin Securities in rendering its opinion.
 
  In arriving at its opinion, Dakin Securities reviewed a draft of the Merger
Agreement and the exhibits thereto, none of which differed materially from
such agreements as executed on July 16, 1997. Dakin Securities also reviewed
(1) the Ansan Form 10-KSB for the fiscal year ended December 31, 1996 and the
Form 10-QSB, for the quarter ended March 31, 1997; (2) the prospectus for the
Ansan initial public offering dated August 8, 1995; (3) internal documents
provided by Ansan which included descriptions of pharmaceutical products under
development, estimated timelines for clinical trials and commercialization of
such products; (4) financial documents provided by Ansan concerning current
and projected cash requirements needed to support Ansan's operations; (5)
stock prices and trading history of Ansan Common Stock; and (6) the Form SB-2
Registration Statement and exhibits filed by Discovery with the Commission. In
addition, Dakin Securities met with and interviewed the senior management of
Ansan with regard to Ansan's drug portfolio, Ansan's efforts to secure
financing from various sources, including Titan, reviewed and considered the
terms of the Titan Sublicense Agreement and the current state of the public
and private equity markets for life science companies similar to Ansan.
 
  In rendering its opinion, Dakin Securities relied upon and assumed the
accuracy and completeness of all of the financial and other information that
was available to it from public sources, that was provided to it by Ansan and
Discovery or their respective representatives, or that it otherwise reviewed.
Dakin Securities did not assume any responsibility for making any independent
evaluation of Ansan's assets or liabilities or for making an independent
verification of any information reviewed by it. Dakin Securities further
assumed that the Merger will qualify as a tax-free reorganization under the
Code.
 
  At the July 16, 1997 meeting, Dakin Securities informed the Board of
Directors of Ansan that any forecast in the pharmaceutical industry is subject
to a number of variables. These variables include the ability to secure
adequate funding to bring products to market, the technological feasibility,
market capacity and market acceptance of products and the competitive risk
presented by other pharmaceutical companies with similar products and/or
better resources. Dakin Securities applied this analytical framework to the
proposed Merger in the manner further described below.
 
 Funding Options
 
  In connection with its engagement, Dakin Securities reviewed Ansan's
historical and projected cash balances and liquidity, together with the other
possible options of Ansan for meeting future funding needs.
 
  As a result of its analysis of Ansan's financial resources and future
commitments, Dakin Securities concluded that Ansan would need a substantial
capital infusion in order to conduct clinical trials for its products and
develop its drug portfolio. Dakin Securities advised the Board of Directors
that it was very unlikely that Ansan would be able to negotiate an arrangement
in a timely manner with a new corporate partner to assist in funding and in
drug development. Regarding other funding possibilities, Dakin Securities felt
that because of the early stage of Ansan's drug portfolio and attendant
uncertainties, it was unlikely sufficient capital could be raised from either
public or private sources to fund future product development and operations.
Consequently, Dakin Securities concluded that Ansan did not have any realistic
near-term funding alternatives.
 
 Transaction Analysis
   
  Dakin Securities noted that the pending delisting from the Nasdaq Small Cap
market would negatively impact Ansan's visibility and ability to obtain
further funding. Dakin Securities advised the Board of Directors that the
consummation of the Merger would improve Ansan's cash position from
approximately $1,700,000 to approximately $11,500,000. This cash infusion
would, in turn, provide (1) sufficient capitalization for Ansan's Common Stock
to continue to qualify for listing on the Nasdaq SmallCap market; and (2)
further funding for clinical trials and development of products.     

                                      42

  The summary of the Dakin Securities analyses set forth above does not
purport to be a complete description of the analysis performed by Dakin
Securities, but describes in summary form all material aspects of the analyses
performed and the principal elements of the presentation made by Dakin
Securities to the Ansan Board of Directors on July 16, 1997.
 
  The preparation of a fairness opinion involves various determinations as to
the most appropriate and relevant methods of financial analysis and the
application of these methods to the particular circumstances and, therefore,
such an opinion is not readily susceptible to summary description. Each of the
analyses conducted by Dakin Securities was carried out in order to provide a
different perspective on the transaction and add to the total mix of
information available. Dakin Securities did not form a conclusion as to
whether any individual analysis, considered in isolation, supported or failed
to support an opinion as to fairness from a financial point of view. Rather,
in reaching its conclusion, Dakin Securities considered the results of the
analyses in light of each other and ultimately reached its opinion based on
the results of all analyses taken as a whole. Dakin Securities did not place
particular reliance or weight on any individual analysis, but instead
concluded that its analyses, taken as whole, supported its determination.
Accordingly, notwithstanding the factors suggested above, Dakin Securities
believes that its analyses must be considered as a whole and that selecting
portions of its analyses or the factors it considered, without considering all
analyses and factors, could create an incomplete view of the process
underlying the analyses performed by Dakin Securities in connection with the
preparation of its opinion. In performing its analyses, Dakin Securities made
numerous assumptions with respect to industry performance, business and
economic conditions and other matters. The analyses performed by Dakin
Securities are not necessarily indicative of actual values or future results,
which may be significantly more or less favorable than suggested by such
analyses.
 
  Dakin Securities' opinion is necessarily based on economic, market,
financial and other conditions as they existed on, and on the information made
available to it as of, the date of its opinion. It should be understood that,
although subsequent developments may have affected its opinion, Dakin
Securities is not obligated to update, review or reaffirm its opinion.
 
  Dakin Securities is a regional investment banking firm. Dakin Securities, as
part of its investment banking business, is regularly engaged in the valuation
of businesses and their securities in connection with mergers, acquisitions,
underwritings, sales and distributions of listed and unlisted securities,
private placements and valuations for estate, corporate and other purposes.

DISCOVERY
 
  Discovery has retained Sands Brothers & Co., Ltd. ("Sands Brothers") to act
as its financial advisor in connection with the fairness, from a financial
point of view, of the consideration to be received by Discovery's stockholders
in connection with the Merger. No instructions or limitations were given to or
imposed upon Sands Brothers in connection with its opinion, nor were any
limitations imposed upon the scope of Sands Brothers' investigation. The
Discovery Board of Directors' approval of the Merger was made subject to its
subsequent receipt of a satisfactory fairness opinion.
 
  Sands Brothers has delivered to the Board of Directors of Discovery its
written opinion dated August 12, 1997, the complete text of which is set forth
as Annex B to this Prospectus/Proxy Statement. Sands Brothers stated that, in
its opinion, based on its review of, among other things, the Merger Agreement,
Discovery's financial position, certain forecasts prepared by Discovery's
management, the trading history and current price of the Ansan Common Stock,
Discovery's stage of clinical and drug development, the public market
valuations of public biotechnology companies deemed comparable in qualitative
and quantitative respects and a comparison of various financial ratios with
respect to such biotechnology companies, and subject to the assumptions,
limitations and qualifications set forth in its opinion, the consideration to
be received by Discovery stockholders in the Merger is fair, from a financial
point of view, to such stockholders as of the date of such opinion. Discovery
stockholders are urged to read such opinion carefully and in its entirety for
a description of the procedures followed, the factors considered and the
assumptions made by Sands Brothers. In rendering its
 
                                      43

opinion, Sands Brothers relied, without independent verification, upon the
accuracy and completeness of the financial and other information reviewed by
it for purposes of its opinion.
 
  For Sands Brothers' above-described services to Discovery in connection with
the Merger, Discovery has agreed to pay Sands Brothers a fee of $100,000 (of
which $50,000 was paid upon execution of Discovery's engagement letter with
Sands Brothers and $50,000 was paid upon delivery of Sands Brothers' opinion).
Discovery has also agreed to reimburse Sands Brothers for certain out-of-
pocket expenses (up to a maximum of $15,000) and to indemnify Sands Brothers
against certain liabilities, including liabilities under the Federal
securities laws, relating to or arising out of services performed by Sands
Brothers as financial advisor to Discovery.
 
  In its memorandum detailing its analysis in arriving at its opinion, Sands
Brothers acknowledged that as a privately held entity, Discovery has no quoted
market value. It is Sands Brothers' view that biotechnology (or "biotech")
firms are unique for valuation purposes and that in today's financial
environment, biotech companies are valued on the basis of their objectives and
their likelihood of success. Not only are historical financial statements of
less overall relevance in valuing firms in the biotech sector than in perhaps
any other industry or sector, but the focus of the financial analysis is on
the balance sheet, and monies invested or expended for research and
development, rather than the income statement.
 
  In assessing the fairness of the proposed stock for stock transaction, a
proxy market value was calculated by Sands Brothers for Discovery as a private
company in order to determine whether the price being paid is fair to the
stockholders of Discovery. In this regard, it was necessary to analyze the
proposed market value of Discovery using a comparability analysis of the price
at which Discovery is being valued under the terms of the proposed Merger.
 
  Sands Brothers' valuation methodology was based in part on its view that
traditional methods of comparative valuation are not usually relevant to
biotech companies, since biotechs, especially smaller, development stage
companies such as Discovery, generally lose money and therefore income
statement valuations based on earnings multiples, Gordon growth calculations
or discounted future cash flows will not produce a viable market value. In
valuing small capitalization biotech companies, a variety of approaches are
used that take a more qualitative approach in valuation than in traditionally
financed industries. However, Sands Brothers believes that such a qualitative
approach must also take account of the cash positions and survival indices of
such companies.
 
  The specific approach taken to valuing Discovery began by looking at
biotechs of a similar size and value that are already publicly traded. Through
examination of their operations, and financial information, Sands Brothers was
able to narrow its comparison in various ways in order to determine how
different criteria might add value to or detract value from an entity
hypothetically comparable to Discovery. Ultimately there are few biotechs that
are directly comparable, even if two firms are of similar size and are
developing drug products intended to treat the same disease, since many
factors (including variability of efficacy of different compounds, different
levels of FDA approval, different developments in clinical trials, varying
strategic relationships, relative competence of management, and others) can
add to or detract from the value of an entity.
 
  Within this context, Sands Brothers assumed that the public market value of
Ansan was a constant as a result of Ansan's defined characteristics,
particularly in light of the prior announcement of the Ansan-Discovery
transaction. Sands Brothers' approach was to ascertain whether the
consideration to be received by Discovery stockholders in terms of Ansan
securities would be at least equal to the consideration it would be giving up
if the Merger were to be consummated, i.e., approximately 10% of the equity in
Discovery. In order to resolve that question, Sands Brothers used a variety of
approaches to determine ranges of value for Discovery. In so doing, Sands
Brothers considered what value might be given to Discovery as a public
corporation by looking at the market valuations of relatively comparable
public biotech companies, taking into account the principle stated above that
there are no perfectly comparable companies, particularly in the biotech
industry.
 
  The comparable companies were viewed from various perspectives to see if the
diverse valuation methodologies converged on a valuation for Discovery. The
methods used included looking at liquidity positions, looking at so-called
burn rates (i.e., how much the companies expended per month), looking at the
clinical stage of development and then looking at a composite of the various
methodologies. The analysis was reinforced by a convergence of the various
methodologies within a relatively small range for the valuation of Discovery.
 
                                      44

  The preparation of a fairness opinion involves various determinations as to
the most appropriate and relevant methods of financial analysis and the
application of these methods to the particular circumstances and, therefore,
such an opinion is not readily susceptible to summary description. Each of the
analyses conducted by Sands Brothers carried out in order to provide a
different perspective on the transaction and add to the total mix of
information available. Sands Brothers did not form a conclusion as to whether
any individual analysis, considered in isolation, supported or failed to
support an opinion as to fairness from a financial point of view. Rather, in
reaching its conclusion, Sands Brothers considered the results of the analyses
in light of each other and ultimately reached its opinion based on the results
of all analyses taken as a whole. Sands Brothers did not place particular
reliance or weight on any individual analysis, but instead concluded that its
analyses, taken as whole, supported its determination. Accordingly,
notwithstanding the factors suggested above, Sands Brothers believes that its
analyses must be considered as a whole and that selecting portions of its
analyses or the factors it considered, without considering all analyses and
factors, could create an incomplete view of the process underlying the
analyses performed by Sands Brothers in connection with the preparation of its
opinion. In performing its analyses, Sands Brothers made numerous assumptions
with respect to the market value of the Ansan Common Stock, as of the date of
the opinion, industry performance, business and economic conditions and other
matters. The analyses performed by Sands Brothers are not necessarily
indicative of actual values or future results, which may be significantly more
or less favorable than suggested by such analyses.
 
  Sands Brothers' opinion is necessarily based on economic, market, financial
and other conditions as they existed on, and on the information made available
to it as of, the date of its opinion. It should be understood that, although
subsequent developments may have affected its opinion, Sands Brothers is not
obligated to update, review or reaffirm its opinion.
 
  In rendering its opinion, Sands Brothers assumed that the market price of
Ansan's Common Stock at the date of such opinion reflected the valuation by
market participants of the Combined Company, i.e., of Ansan following the
consummation of the Merger and the Titan Sublicense Agreement. Sands Brothers'
analytic approach did not require a comparative valuation of the consideration
to be transferred to Titan and the consideration to be received by Ansan
pursuant to the Titan Sublicense Agreement. Accordingly, Sands Brothers did
not separately consider the terms of the Titan Sublicense Agreement.
 
  The foregoing summary of Sands Brothers' opinion describes all material
aspects of the analyses performed by Sands Brothers.
   
  The summary of the Sands Brothers analyses set forth above does not purport
to be a complete description of the analysis performed by Sands Brothers, but
describes in summary form certain of the analyses employed by Sands Brothers
in reaching its determination.     
   
  Pursuant to Discovery's engagement letter with Sands Brothers, Discovery was
entitled to have Sands Brothers' fairness opinion updated as of a date no
earlier than three days prior to the mailing of this prospectus/proxy
statement. Sands Brothers advised Discovery on or about October 22, 1997 that
it could not conclude that the Exchange Ratio is fair to Discovery
stockholders from a financial point of view as of such date because of a
combination of the decline in the trading price of Ansan since the date of
Sands Brothers' opinion and an increase in the trading price of certain public
company comparables considered by Sands Brothers in its original opinion.
Discovery therefore did not require an updated opinion to be delivered.     
   
  The decline in the trading price of Ansan Common Stock since the date of the
Sands Brothers opinion (and the possibility of a further decline in such
trading price between the date hereof and the Closing Time; see "Risk
Factors--Risks Related to the Merger; Risks Associated with Fixed Exchange
Ratios") relative to the public company comparables examined by Sands Brothers
has not caused the Discovery Board to withdraw its recommendation to
stockholders to approve the Merger. In recommending the Merger to Discovery
stockholders, the Discovery Board has taken into account a variety of
financial and nonfinancial considerations that are unaffected by changes in
the trading price of the Ansan Common Stock, either in isolation or relative
to other biotechnology companies, including the opportunity presented by the
Merger to achieve greater liquidity and potentially stronger performance of
Discovery's equity securities by securing a trading market for such securities
and the other matters described under "The Merger and Related Transactions--
Discovery's Reasons for the Merger".     
 
                                      45

                              TERMS OF THE MERGER
 
  The detailed terms of, and conditions to, the Merger are contained in the
Agreement and Plan of Reorganization and Merger (including the Exhibits
thereto) and the Certificate of Merger, copies of which are attached to this
Prospectus/Proxy Statement as Annex C and Annex D, respectively, and
incorporated herein by reference. The statements made in this Prospectus/Proxy
Statement with respect to the terms of the Merger and related transactions are
qualified in their entirety by the text of those Agreements, collectively
referred to herein as the "Merger Agreement".
 
EFFECTIVE TIME OF THE MERGER
 
  The Merger Agreement provides for the merger of Discovery with and into
Ansan, with Ansan to be the surviving corporation. As a result of the Merger,
Discovery will cease to exist and all of its assets and liabilities will be
assumed by Ansan. It is anticipated that the Ansan Certificate Amendment
effecting a reverse stock split may occur prior to the Effective Time, with
the ratio of the reverse stock split determined (within the range approved at
the Ansan Special Meeting) by the Ansan Board of Directors at such time as the
Ansan Certificate Amendment is effected. If the Ansan Certificate Amendment is
effected prior to the Effective Time, the Common Exchange Ratio will be
adjusted in proportion to the reverse stock split experienced by the holders
of Ansan Common Stock.
   
  The Merger will be effective when the Certificate of Merger is filed with
the Secretary of State of the State of Delaware in accordance with the DGCL.
See "Terms of the Merger--Conditions to the Merger." It is anticipated that,
if the Merger is approved at the Ansan Special Meeting and pursuant to the
Discovery Written Consent and all other conditions to the Merger have been
fulfilled or waived, the Certificate of Merger will be filed on or about
November 24, 1997.     
 
MANNER AND BASIS OF CONVERTING SHARES
 
  As of the Effective Time and subject to adjustment for the Ansan Certificate
Amendment, each issued and outstanding share of Discovery Common Stock (other
than shares, if any, as to which appraisal rights have been exercised pursuant
to the DGCL) will be converted into 1.167471 shares of Ansan Common Stock and
each issued and outstanding share of Discovery Series A Preferred Stock (other
than shares, if any, as to which appraisal rights have been exercised pursuant
to the DGCL) will be converted into one share of Ansan Series B Preferred
Stock.
 
  No fractional shares of Ansan Common Stock will be issued in connection with
the Merger. In lieu of fractional shares, each Discovery stockholder who would
otherwise be entitled to a fractional share will receive cash equal to such
fraction multiplied by the fair market value of the Ansan Common Stock
determined based on the average of the last reported closing bid prices of the
Ansan Common Stock over the 20 trading days preceding the closing of the
Merger. Based upon the number of outstanding shares of Ansan Common Stock and
Discovery Common Stock as of the Record Date, and assuming that (i) no
Discovery or Ansan stockholders exercise appraisal rights, and (ii) no
outstanding Ansan or Discovery options or warrants are exercised prior to the
Merger, approximately 9,516,524 shares of Ansan Common Stock will be
outstanding as of the Effective Time, of which approximately 7,877,225 shares
(approximately 83% of the total), will be issued to the former holders of
Discovery Common Stock. Approximately 2,200,256 shares of Ansan Series B
Preferred Stock will be outstanding, all of which will be held by the former
holders of Discovery Series A Preferred Stock. Accordingly, the former holders
of Discovery Stock as a group will be in a position to have a significant
influence on the election of directors and other corporate matters which
require the vote of Ansan stockholders.
 
  The financial terms of the Merger, including the Exchange Ratios, were
negotiated at arm's length by representatives of Ansan and Discovery (and
Titan, to the extent of the Titan Sublicense Agreement).
 
                                      46

EXCHANGE OF CERTIFICATES
 
  On or prior to the Effective Time, Ansan will mail or otherwise deliver to
each Discovery stockholder of record a letter of transmittal with instructions
to be used by such stockholder in surrendering certificates that, prior to the
Merger, represented shares of Discovery Stock (the "Discovery Stock
Certificates").
 
  Upon surrender of a Discovery Stock Certificate to Ansan, together with a
duly executed letter of transmittal, Ansan and Continental Stock Trust &
Transfer Company, Ansan's transfer agent, as exchange agent (the "Exchange
Agent"), will arrange for the holder of such certificate to receive in
exchange therefor certificates evidencing the number and type of shares of
Ansan Stock to which such holder of Discovery Stock is entitled (and cash for
any fractional share of Ansan Common Stock). In the event there has been a
transfer of ownership of shares of Discovery Stock that is not reflected on
the transfer records of Discovery, Ansan Stock may be delivered to a
transferee if the certificate representing such Discovery Stock is presented
to Ansan, together with the related letter of transmittal, and accompanied by
all documents required to evidence and effect such transfer and to evidence
that any applicable stock transfer taxes have been paid.
 
  Until a Discovery Stock Certificate has been surrendered to Ansan, each such
certificate shall be deemed at any time after the Effective Time to represent
the right to receive, upon such surrender, certificates for such number and
type of shares of Ansan Stock as the stockholder is entitled to receive under
the Merger Agreement. After the Effective Time, there will be no further
registrations of transfers of Discovery Stock.
 
  DISCOVERY STOCKHOLDERS SHOULD NOT SURRENDER THEIR CERTIFICATES FOR EXCHANGE
PRIOR TO APPROVAL OF THE MERGER BY THE ANSAN AND DISCOVERY STOCKHOLDERS.
 
CHANGE OF NAME
   
  The Merger Agreement provides that Ansan will change its name to Discovery
Laboratories, Inc. at the Effective Time pursuant to the Certificate of Merger
that is to be filed with the Secretary of State of the State of Delaware. This
change of name is desired to more accurately reflect the Combined Company's
composition and goals as a consequence of the Merger. A vote in favor of the
Merger Proposal shall also be a vote in favor of such change of name.     
 
CONDUCT OF BUSINESS PRIOR TO THE MERGER
 
  Under the Merger Agreement, Ansan has agreed that, until the Effective Time,
it will carry on its business in the ordinary and usual course, use its best
efforts to carry on and preserve its business and relationships in
substantially the same manner as it has prior to the Merger Agreement, use its
best efforts to keep and maintain existing favorable business relationships,
and will not, without the prior written consent of Discovery, enter into
certain specified transactions outside the ordinary course of business.
Specifically, Ansan will not, without the prior written consent of Discovery:
 
    (a) borrow any money;
 
    (b) incur any liability except for those that may be incurred (i) in the
  ordinary course of business, consistent with past practice, and are not
  material in amount or (ii) in connection with the performance or
  consummation of the Merger Agreement;
 
    (c) encumber or permit to be encumbered any of its assets except in the
  ordinary course of its business consistent with past practice;
 
    (d) dispose of any of its assets, except inventory in the ordinary course
  of business, consistent with past practice;
 
    (e) enter into any material lease or contract for the purchase or sale of
  any property, real or personal, except in the ordinary course of business,
  consistent with past practice;
 
                                      47

    (f) fail to maintain its equipment and other assets in good working
  condition and repair according to the standards it has maintained such
  equipment and other assets to the date of the Merger Agreement, subject
  only to ordinary wear and tear;
 
    (g) pay any bonus, increased salary, or special remuneration to any
  officer, employee (other than those paid in the ordinary course of
  business, consistent with past practice) or consultant or enter into any
  new employment or consulting agreement with any such person, except in the
  ordinary course of business, consistent with past practice;
 
    (h) change accounting methods;
 
    (i) declare, set aside or pay any cash or stock dividend or other
  distribution in respect of capital stock, or redeem or otherwise acquire
  any of its capital stock (except pursuant to employee stock repurchase
  agreements upon termination of an employee consistent with its past
  practice);
 
    (j) amend or terminate any contract, agreement or license to which it is
  a party except those amended or terminated in the ordinary course of
  business consistent with past practice, and which are not material in
  amount;
 
    (k) loan any amount to any person or entity, other than advances for
  travel and expenses which are incurred in the ordinary course of business
  consistent with past practice, not material in amount and documented by
  receipts for the claimed amounts;
 
    (l) guarantee or act as a surety for any obligation except for the
  endorsement of checks and other negotiable instruments in the ordinary
  course of business, consistent with past practice, which are not material
  in amount;
 
    (m) waive or release any material right or claim except in the ordinary
  course of business, consistent with past practice;
 
    (n) issue or sell any shares of its capital stock of any class (except
  upon the exercise of an option currently outstanding, as disclosed in the
  Merger Agreement or granted in accordance with the terms of the Merger
  Agreement), or any other of its securities, or issue or create any
  warrants, obligations, subscriptions, options, convertible securities, or
  other commitments to issue shares of capital stock without the prior
  written consent of the other party hereto, which consent shall not be
  withheld unreasonably if options are being granted for the purpose of
  recruiting new personnel in accordance with the past practices regarding
  the pricing, the total number of options granted, the options awarded in
  relation to the job title of the recipient and the timing of the option
  awards;
 
    (o) accelerate the vesting of any outstanding options;
 
    (p) split or combine the outstanding shares of its capital stock of any
  class or enter into any recapitalization affecting the number of
  outstanding shares of its capital stock of any class or affecting any other
  of its securities;
 
    (q) merge, consolidate or reorganize with, or acquire any entity, except
  for the Merger or amend its Certificate of Incorporation or Bylaws, except
  as expressly contemplated by the Merger Agreement;
 
    (r) other than pursuant to the Titan Sublicense Agreement, license any of
  its technology or intellectual property, except in the ordinary course of
  business; or
 
    (s) agree to do any of the things described in the preceding clauses (a)
  to (r) or fail to conduct itself in material compliance with the Operating
  Budget.
 
  As provided in item (s) above, until the Effective Time, Ansan is obligated
to operate within the parameters of the Operating Budget. The Merger Agreement
also provides that, in the event that Ansan fails to operate within the
parameters of such Operating Budget, then Discovery shall have the right to
unilaterally terminate the Merger Agreement. See "The Merger and Related
Transactions--Background to the Merger" for further information on this
limitation and the consequences of a failure by Ansan to comply with the
Operating Budget.
 
                                      48

  Each of Ansan and Discovery has agreed, until the termination of the Merger
Agreement, not to directly or indirectly encourage, solicit, initiate,
facilitate or conduct discussions or negotiations with, provide any
information to, or enter into any agreement with, any corporation,
partnership, person or other entity or group concerning or expressing an
interest in or proposing any merger, consolidation, reorganization, share
exchange, business combination, liquidation, dissolution, sale of all or
significant assets or securities or other similar transaction involving Ansan
or Discovery, except to the extent required by their fiduciary duties as
determined by the Boards of Directors of Ansan or Discovery, as the case may
be, after discussion with their counsel.
 
  Each company has also agreed to advise the other of any event that would
render any representation or warranty contained in the Merger Agreement untrue
or inaccurate in any material respect and of any material adverse change in
the company's financial position, results of operations, assets, liabilities
or business and of any material non-compliance by Ansan with respect to the
Operating Budget or by Discovery with respect to its obligation to maintain at
least $5,000,000 in working capital on a non-consolidated basis. Each company
has further agreed to advise the other of any material action, suit,
proceeding or investigation initiated by or against it, or known by the
company to be threatened against it and to use its best efforts to obtain all
authorizations, approvals and consents necessary for the consummation of the
Merger.
 
  In addition, each company has agreed to afford to the other reasonable
access to its corporate books and records, and to cause its accountants,
officers, directors and stockholders to cooperate with the other company in
making available all material information reasonably requested.
 
CONDITIONS TO THE MERGER
   
  In addition to the approval by the stockholders of Ansan and Discovery of
the Merger Proposal, the obligations of Ansan and Discovery to consummate the
Merger are subject to the satisfaction of a number of conditions, including:
(a) the effectiveness of the Registration Statement on Form S-4 filed by Ansan
with respect to the shares of Ansan Common Stock and Ansan Series B Preferred
Stock to be issued to the Discovery stockholders under the Merger Agreement,
the absence of any stop orders or proceedings with respect to the Form S-4,
the absence of any proceeding commenced or threatened by the Commission with
respect to the Prospectus/Proxy Statement contained therein and the approval
for listing by the NASD of the shares of Ansan Common Stock to be issued as a
result of the Merger; (b) the accuracy of the representations and warranties
made in the Merger Agreement; (c) the performance of the covenants contained
in the Merger Agreement (d) the receipt of agreements regarding compliance
with Rule 145 under the Securities Act from certain Discovery stockholders and
the receipt of certain lockup agreements from Discovery stockholders holding
85% of the outstanding voting securities of Discovery; (e) the receipt by each
party of a certificate signed by the other party's President certifying to the
fulfillment of certain conditions to the Merger; (f) the number of shares held
by either Ansan or Discovery stockholders for which appraisal rights have been
exercised not exceeding 5% of the shares of Ansan Common Stock or Discovery
Common Stock, as the case maybe, held prior to the Merger; (g) the
cancellation of all Ansan Stock owned by Titan; (h) all action having been
taken to provide for the Ansan Board structure specified herein; (i) Discovery
maintaining at least $5,000,000 in working capital on a non-consolidated
basis; (j) the receipt by each of Ansan and Discovery of all permits or
authorizations as may be required by regulatory authorities and all other
written consents necessary to provide for the continuation of certain material
contracts and leases of the other; (k) the reasonable satisfaction of Ansan
that consummation of the Merger will not confer upon preferred stockholders of
Discovery or ATI the right to a distribution of the liquidation preference
afforded to such stockholders; and (l) the receipt of legal opinions and other
closing documents.     
   
  At any time at or prior to the Effective Time, to the extent legally
allowed, either of Ansan or Discovery, without approval of the stockholders of
such company, may waive compliance with any of the agreements or conditions
contained in the Merger Agreement for the benefit of such company. No
agreement has been reached between Ansan and Discovery as to the prospective
waiver of any provision of the Merger Agreement. However, it appears likely
that Discovery will waive the requirement that a determination be made prior
to the Closing Time that the Combined Company will satisfy all NASDAQ listing
requirements since it will be impossible to determine prior to the Closing
whether listing requirements relating to the trading price of the Combined
Company's common stock will be capable of being satisfied. In addition, it is
likely the parties would waive conditions to the Merger of relatively minor
significance, if such conditions could not be practicably fulfilled,     
 
                                      49

rather than terminate the Merger Agreement and forego the expected benefits of
the Merger. Without limitation of the foregoing, the failure of a party to the
Merger Agreement to be able to restate its capitalization representations set
forth in the Merger Agreement due to the issuance, subsequent to the execution
of the Merger Agreement, of regularly scheduled option compensation to
directors would likely be waived.
 
TERMINATION OR AMENDMENT OF MERGER AGREEMENT
 
  The Merger Agreement may be terminated at any time prior to the Effective
Time, without regard to whether stockholder approval of the Merger has been
obtained: (a) by mutual consent of Ansan and Discovery; (b) by either Ansan or
Discovery if any of the conditions precedent to the obligations of such party
have not been fulfilled; or (c) by Discovery, if Ansan fails in any material
respect to comply with the terms of the Operating Budget. See "Terms of the
Merger--Conditions to the Merger".
 
  The Merger Agreement may be amended by the parties thereto at any time prior
to the approval of the Merger by the stockholders of Discovery and Ansan.
After such approval has been obtained, amendments to the Merger Agreement may
be made without further stockholder approval. However, no amendment may be
made without further stockholder approval it if would alter or change (i) any
of the principal terms of the Merger Proposal, or (ii) any of the terms and
conditions of the Merger Agreement if such alteration or change would
adversely affect the holders of shares of Discovery Stock or shares of Ansan
Stock.
 
ARRANGEMENTS WITH TITAN
 
  Under the terms of the Merger Agreement, effective upon the closing of the
Merger, Ansan will grant to Titan an exclusive, worldwide sublicense under the
Bar-Ilan License Agreement of certain development rights with respect to the
family of compounds licensed to Ansan under the Bar-Ilan License Agreement. To
date, Ansan has pursued development of two compounds, AN9 and AN10, pursuant
to the Bar-Ilan License Agreement. Under the terms of the Titan Sublicense
Agreement, Ansan will receive a fee of 2% of net sales of the licensed
products and Titan will surrender all Ansan Common Stock to Ansan at the
Effective Time. Additionally, Discovery's obligation to consummate the Merger
is conditioned upon Ansan repaying approximately $1,200,000 in debt owed to
Titan. See "Information Concerning Ansan--Relationship with Titan
Pharmaceuticals, Inc."
 
ACCOUNTING TREATMENT OF MERGER
 
  As Discovery's stockholders will hold approximately 92% of the outstanding
shares of the merged entity, on a fully converted basis, the Merger will be
treated as an acquisition of Ansan by Discovery. The Merger will be accounted
for using the purchase method, whereby the purchase price will be allocated
based on the fair value of the assets acquired and liabilities assumed. It is
anticipated that a significant portion of the purchase price will be allocated
to in-process research and development which will result in a charge to the
consolidated statement of operations of approximately $2.9 million in the
quarter in which the Merger closes. The amount of the estimated charge is
based on a preliminary evaluation and could vary upon completion of a final
valuation analysis.
 
CERTAIN FEDERAL INCOME TAX CONSEQUENCES
 
  The following discussion summarizes certain Federal income tax consequences
of the Merger to holders of Discovery Stock. The discussion does not address
all aspects of Federal income taxation that may be relevant to particular
Discovery stockholders, such as stockholders who are dealers in securities,
foreign persons, or stockholders who acquired their shares in connection with
stock option or stock purchase plans or other compensatory transactions, nor
does the discussion address the tax consequences of transactions effected
prior to or after the Merger (whether or not in connection with the Merger),
nor the effect of any applicable foreign, state, local or other tax laws. This
discussion assumes that Discovery stockholders hold their Discovery Stock as
capital assets within the meaning of Section 1221 of the Internal Revenue Code
of 1986, as amended (the "Code"). EACH STOCKHOLDER SHOULD CONSULT HIS OR HER
OWN TAX ADVISOR AS TO THE PARTICULAR TAX CONSEQUENCES TO HIM OR HER OF THE
MERGER, INCLUDING THE APPLICABILITY AND EFFECT OF FEDERAL, STATE, LOCAL AND
FOREIGN TAX LAWS.
 
                                      50

  The Merger is expected to constitute a reorganization within the meaning of
Section 368(a) of the Code, with each of Discovery and Ansan qualifying as a
party to the reorganization under Section 368(b) of the Code, in which case
the following tax consequences will result (subject to the limitations and
qualifications referred to herein):
 
    1. No gain or loss will be recognized by holders of Discovery Stock as a
  result of the exchange of such shares solely for shares of Ansan Stock
  pursuant to the Merger.
 
    2. Gain or loss will be recognized on the receipt of cash paid to a
  Discovery Shareholder in lieu of a fractional share of Ansan Common Stock.
  Any cash received by a stockholder of Discovery in lieu of a fractional
  share will be treated as received in exchange for such fractional share and
  not as a dividend, and any gain or loss recognized as a result of the
  receipt of such cash will be capital gain or loss equal to the difference
  between the cash received and the portion of the stockholder's basis
  allocable to the Ansan Stock for which such cash was received.
 
    3. The aggregate tax basis of the shares of Ansan Stock received by each
  stockholder of Discovery will equal the aggregate tax basis of such
  stockholder's shares of Discovery Stock (reduced by any amount allocable to
  a fractional share of Discovery Stock for which cash is received) exchanged
  in the Merger.
 
    4. The holding period for the shares of Ansan Stock received by each
  stockholder of Discovery in the Merger will include the period during which
  such stockholder held the shares of Discovery Stock surrendered in exchange
  therefor.
 
    5. Neither Ansan nor Discovery will recognize gain or loss as a result of
  the Merger.
 
  In addition, whether or not the Merger qualifies as a reorganization, the
future use of Ansan's net operating loss carryovers will be limited by reason
of the acquisition by former Discovery stockholders of more than 50% of the
stock of Ansan.
   
  The parties are not requesting a ruling from the Internal Revenue Service
("IRS") in connection with the Merger. Discovery and Ansan will have each
received an opinion from its legal counsel, Roberts, Sheridan & Kotel and
Heller Ehrman White & McAuliffe, respectively, to the effect that, for Federal
income tax purposes, the Merger will qualify as a "reorganization" within the
meaning of Section 368(a) of the Code. These opinions, which are collectively
referred to herein as the "Tax Opinions," neither bind the IRS nor preclude
the IRS from adopting a contrary position. In addition, the Tax Opinions are
subject to certain assumptions and qualifications and are based on the truth
and accuracy of certain representations made by Ansan, Discovery and certain
Discovery stockholders, including representations in certificates delivered to
counsel by the respective managements of Discovery and Ansan, including
representation to the effect that, Discovery stockholders do not intend,
pursuant to a plan or intent existing at or prior to the Merger, to dispose of
or transfer so much of either (i) their Discovery Common Stock in anticipation
of the Merger, or (ii) the Ansan Common Stock received in the Merger, such
that the Discovery stockholders, as a group, would no longer have a
substantial proprietary interest in the business being conducted by the
Combined Company after the Merger.     
       
  A successful IRS challenge to the "reorganization" status of the Merger
would result in a Discovery stockholder recognizing gain or loss with respect
to each share of Discovery Common Stock surrendered equal to the difference
between such stockholder's basis in such stock and the fair market value, as
of the time of the Merger, of the Common Stock received in exchange therefor.
In such event, a stockholder's aggregate basis in the Ansan Common Stock so
received would equal such fair market value and his holding period for such
stock would begin the day after the Merger.
 
                                      51

MANAGEMENT AFTER THE MERGER
 
 Directors
   
  Immediately following the Effective Time, the Board of Directors of the
Combined Company will consist of ten members, who will be: Vaughan H. J.
Shalson and Richard Sperber, each of whom is presently a director of Ansan
(see "Information Concerning Ansan Management"); James S. Kuo, Steve H.
Kanzer, Evan Myrianthopoulos, Juerg F. Geigy, Max Link, Herbert H. McDade, Jr.
and Mark C. Rogers, each of whom is presently a director of Discovery (see
"Information Concerning Discovery Management); and David Naveh, Ph.D. who is a
nominee of D.H. Blair. All such directors will serve until their successors
have been duly elected and qualified or otherwise as provided by law. If the
Merger is approved, at the Effective Time, all current Ansan directors other
than those named above will resign and the current Ansan directors named above
will (i) adopt a resolution increasing the size of the Ansan Board to ten
directors, and (ii) appoint the seven Discovery directors and the one D.H.
Blair director named above to the Board, to bring the total to the ten
directors identified above. As a result of this process, a vote in favor of
the Merger will, in effect, be a vote in favor of the seven Discovery
directors and one D.H. Blair director named above.     
 
 Officers
   
  After the Merger, James S. Kuo, currently Chief Executive Officer of
Discovery will be the Chief Executive Officer of the Combined Company. Other
principal officers of the Combined Company will be Evan Myrianthopoulos, who
will serve as Chief Operating Officer of the Combined Company, and Robert
Capetola, who will serve as the Chief Executive Officer of ATI, a majority-
owned subsidiary of Discovery that will be a majority-owned subsidiary of the
Combined Company.     
 
VOTING AGREEMENTS
 
  In connection with the execution of the Merger Agreement, the directors of
Discovery as well as RAQ, LLC, a principal stockholder of Discovery, have each
agreed with Ansan to vote all shares of Discovery Stock held by them in favor
of the Merger Proposal. This agreement is not intended to prohibit any
stockholder who is also a director or officer of Discovery from acting in
accordance with such stockholder's fiduciary duty as a director or officer of
Discovery.
 
AFFILIATES' RESTRICTIONS ON SALE OF ANSAN STOCK
 
  The shares of Ansan Stock to be issued in the Merger are being registered
under the Securities Act by a Registration Statement on Form S-4, thereby
allowing such securities to be traded without restriction by any former holder
of Discovery Stock: (i) who is not deemed to be an "affiliate" of Discovery
prior to the consummation of the Merger, as such term is defined for purposes
of Rule 145 under the Securities Act; and (ii) who does not become an
"affiliate" of Ansan after the Merger. All Discovery stockholders who may be
deemed affiliates of Discovery have been so advised.
 
  Discovery will cause each Discovery stockholder to agree not to make any
public sale of any Ansan Stock received upon consummation of the Merger except
in compliance with Rule 145 under the Securities Act or otherwise in
compliance with the Securities Act. In general, Rule 145, as currently in
effect, imposes restrictions on the manner in which such affiliates may make
resales of Ansan Stock and also on the quantity of resales that such
stockholders, and others with whom they may act in concert, may make after
consummation of the Merger.
 
ADDITIONAL RESTRICTIONS ON SALE OF ANSAN STOCK
 
  In connection with its solicitations of stockholder consents, Discovery is
seeking from its stockholders, optionholders and warrantholders, agreements
not to make any sales of Ansan Stock within the time periods outlined below.
Discovery securityholders who will receive Ansan Common Stock, Ansan Preferred
Stock or Ansan options or warrants to obtain such securities pursuant to the
terms of the Merger Agreement (other than those who acquired Discovery Stock
pursuant to the Unit Offering (the "1996 Private Placement Investors")), are
being requested to agree not to make any sale, transfer or other disposition
(with certain exceptions regarding intra-family transfers) prior to the first
anniversary of the Effective Time without the prior written consent of Ansan.
The 1996 Private Placement Investors are being requested to agree not to make
any sale, transfer or other disposition (with certain exceptions regarding
intra-family transfers) of the Ansan securities to be received by such
investors in the Merger within the first anniversary of the Effective Time,
without the prior written consent of Ansan, of in excess of 20% of their Ansan
Stock on or after the Effective Time and an additional 20% of
 
                                      52

their Ansan Stock on or after the end of each three-month period after the
Effective Time (in each case on an as-converted basis). It is a condition to
Ansan's obligation to consummate the Merger that such agreements be obtained
with respect to 85% of Discovery's outstanding voting securities.
 
GOVERNMENTAL AND REGULATORY APPROVALS
 
  Ansan and Discovery are not aware of any governmental or regulatory
approvals required for consummation of the Merger, other than compliance with
applicable securities and "blue sky" laws of various states and the filing and
recording of the Certificate of Merger required under the DGCL.
 
MERGER EXPENSES
 
  Whether or not the Merger is consummated, Ansan and Discovery will be
responsible for their own costs and expenses incurred in connection with the
Merger and the transactions contemplated thereby, except that if the Merger is
consummated, any such expenses which are then unpaid will be the
responsibility of the Combined Company.
 
APPRAISAL RIGHTS
 
  Pursuant to Section 262 of the DGCL ("Section 262"), any Ansan or Discovery
stockholders who do not vote in favor of the approval and adoption of the
Merger Agreement (by voting against or abstaining) and who have met the
conditions of, and properly complied with the requirements of, Section 262
will be entitled to appraisal rights. The following summary of Section 262
should be read in conjunction with, and is qualified in its entirety by, the
full text of Section 262, which is attached as Annex E to this
Prospectus/Proxy Statement. By failing to follow the statutory procedures set
forth in Section 262, a stockholder may terminate or waive such holder's
appraisal rights.
 
  Stockholders of record who wish to assert appraisal rights must submit a
written demand for such appraisal before the vote on the Merger is taken, or
in the case of written consents within 20 days of the mailing of this
Prospectus/Proxy Statement. Such written demand must be in addition to and
separate from any proxy or vote against the Merger; and neither voting
against, abstaining from voting, nor failing to vote on the Merger will
constitute a demand for appraisal within the meaning of Section 262.
 
  Within ten days after the Effective Time, the Combined Company will give
written notice of the effectiveness of the Merger to all stockholders of
record who filed a written demand for appraisal and who did not vote in favor
of or consent to the Merger. Within 120 days after the Effective Time, any
such stockholder, upon written request, shall have the right to receive from
the Combined Company a statement setting forth the aggregate number of shares
not voted in favor of the Merger and with respect to which demands for
appraisal have been received, and the aggregate number of holders of such
shares.
 
  If the Combined Company and such stockholder do not agree upon the value of
such holder's shares of stock, either the Combined Company or such holder may
file within 120 days after the Effective Time a petition in the Delaware Court
of Chancery demanding a determination of the value of such stockholder's
shares. In any such proceeding, the Court shall determine the fair market
value of the shares exclusive of any element of value arising from the
accomplishment or expectation of the Merger, together with a fair rate of
interest, if any, to be paid upon the fair value of the shares. The costs of
the proceeding may be determined by the Court and assessed against the parties
as the Court deems equitable in the circumstances. In addition, the Court may,
upon application of a stockholder, order all or any part of the expenses
incurred by such holder in connection with the appraisal proceeding,
including, without limitation, reasonable attorneys' fees and expenses and the
fees and expenses of experts, to be charged pro rata against the value of all
the shares entitled to an appraisal. Notwithstanding the foregoing, at any
time within 60 days after the Effective Time, any such stockholder shall have
the right to withdraw such holder's demands for appraisal and to accept the
terms offered in the Merger. If no such petition for an appraisal is filed
within 120 days of the Effective Time, then the right of such stockholder to
appraisal shall cease.
 
                                      53

  Any such stockholder who has demanded appraisal rights shall thereafter
neither be entitled to vote such holder's shares for any purpose nor be
entitled to the payment of dividends or other distributions on such shares
(except any dividends or other distributions payable to stockholders of record
at a date which is prior to the Effective Time) unless such holder's right to
appraisal shall cease. If no petition for an appraisal shall be filed within
120 days of the Effective Time with the Delaware Court of Chancery or if such
holder delivers to the Combined Company a written withdrawal of such holder's
demand for an appraisal and an acceptance of the Merger, either within 60 days
after the Effective Time or thereafter with the written approval of the
Combined Company, then such holder's right to appraisal shall cease.
 
  IT IS A CONDITION OF THE MERGER AGREEMENT THAT THE AGGREGATE NUMBER OF
SHARES OF ANSAN STOCK AND DISCOVERY STOCK, WITH RESPECT TO WHICH APPRAISAL
RIGHTS ARE EXERCISED NOT EXCEED FIVE (5%) PERCENT OF THE AGGREGATE ANSAN STOCK
OR DISCOVERY STOCK, RESPECTIVELY, OUTSTANDING IMMEDIATELY PRIOR TO THE MERGER.
IN THE EVENT THAT EITHER SUCH THRESHOLD IS EXCEEDED, THEN NOTWITHSTANDING THE
PERCENTAGE OF APPROVAL FOR THE MERGER PROPOSAL OBTAINED IN A VOTE AT THE ANSAN
SPECIAL MEETING OR PURSUANT TO THE DISCOVERY WRITTEN CONSENT, THE MERGER MAY
BE TERMINATED BY EITHER ANSAN OR DISCOVERY.
 
  Appraisal rights are exercisable only by the holder of record, not by a
beneficial owner who does not hold the shares of record.
 
DISCOVERY STOCK OPTIONS AND WARRANTS
 
  As of July 31, 1997, 1,250,000 shares of Discovery Common Stock were
reserved for issuance pursuant to Discovery's 1996 Stock Option Plan (the
"Discovery Option Plan"), of which options to purchase a total of 661,500
shares of Discovery Common Stock were outstanding. The terms of the Discovery
Option Plan allow outstanding options to be assumed by a successor company in
a transaction such as the Merger.
 
  All outstanding and unexercised options to acquire Discovery Common Stock
(the "Discovery Options") under the Discovery Option Plan will be assumed by
Ansan upon consummation of the Merger. Each such Discovery Option will become
exercisable for a number of shares of Ansan Common Stock equal to the number
of shares of Discovery Common Stock issuable upon exercise of the Discovery
Option immediately prior to the Merger multiplied by the Common Exchange Ratio
(as adjusted pursuant to the Ansan Certificate Amendment in the event that the
Reverse Stock Split is effected prior to the Effective Time) at an exercise
price per share equal to the original exercise price per share divided by the
Common Exchange Ratio and will otherwise have the same exercise period and
other terms and conditions.
 
  As of July 31, 1997, 1,100,130 shares of Discovery Common Stock were
reserved for issuance pursuant to exercise of Discovery's outstanding warrants
(the "Discovery Warrants") and upon conversion of preferred stock subject to
such warrants. The terms of such warrants allow such outstanding warrants to
be assumed by a successor company in a transaction such as the Merger.
 
  The Discovery Warrants will be assumed by Ansan upon consummation of the
Merger. Each such Discovery Warrant for Discovery Common Stock will, following
the Merger, entitle the holder thereof to purchase that number of shares of
Ansan Common Stock as is equal to the number of shares of Discovery Common
Stock issuable upon exercise of such Discovery Warrant immediately prior to
the Merger multiplied by the Common Exchange Ratio (as adjusted pursuant to
the Ansan Certificate Amendment in the event that the Reverse Stock Split is
effected prior to the Effective Time) at an exercise price per share equal to
the original exercise price per share divided by the Common Exchange Ratio and
will otherwise have the same terms and conditions. Each Discovery Warrant for
Discovery Series A Preferred Stock will, following the Merger, entitle the
holder thereof to purchase the number of shares of Ansan Series B Preferred
Stock as is equal to the number of shares of Discovery Series A Preferred
Stock issuable upon exercise of such Discovery Warrant immediately prior to
the Merger at a per share exercise price equal to the original per share
exercise price and will otherwise have the same terms and conditions.
 
                                      54

        UNAUDITED PRO FORMA CONDENSED CONSOLIDATED FINANCIAL STATEMENTS
 
  The following unaudited pro forma condensed combined financial statements
give effect to the merger of Ansan and Discovery pursuant to the Merger
Agreement. The unaudited pro forma condensed consolidated balance sheet gives
effect to the Merger as if it occurred on June 30, 1997. The unaudited pro
forma condensed consolidated statements of operations gives effect to the
Merger as if it occurred on January 1, 1996 and January 1, 1997 respectively.
 
  The pro forma condensed consolidated financial statements are based on the
historical financial statements of Ansan and Discovery. They give effect to
the Merger under the purchase method of accounting and apply the assumptions
and adjustments as discussed in the accompanying notes to the pro forma
condensed consolidated financial statements. The pro forma condensed
consolidated financial statements for the year ended December 31, 1996 have
been prepared based upon the audited financial statements of Ansan for the
year then ended and the audited consolidated financial statements of Discovery
for the year then ended. The pro forma condensed consolidated financial
statements as of and for the six months ended June 30, 1997 have been prepared
based upon the unaudited condensed financial statements of Ansan and the
unaudited condensed consolidated financial statements of Discovery as of June
30, 1997 and for the six months then ended.
 
  The Merger will be accounted for using the purchase method of accounting.
Although Ansan will be the surviving corporate entity, Discovery's current
stockholders will own approximately 92% of the merged entity. Accordingly, the
transaction will be accounted for as an acquisition of Ansan by Discovery. The
unaudited pro forma condensed consolidated financial statements have been
prepared on the basis of assumptions described in the notes thereto and
include assumptions relating to the allocation of the consideration paid for
the assets and liabilities of Ansan based on preliminary estimates of their
fair value. The actual allocation of such consideration may differ from that
reflected in the unaudited pro forma condensed consolidated financial
statements after final valuation procedures are completed following the
closing of the Merger. The final allocations of the aggregate purchase price
for the Merger is not expected to differ materially from the preliminary
allocations. In the opinion of Ansan and Discovery, all adjustments necessary
to present fairly the unaudited pro forma condensed consolidated financial
statements have been made based on the proposed terms and structure of the
Merger.
 
  The pro forma information is presented for illustrative purposed only and is
not necessarily indicative of the operating results or financial position that
would have occurred if the Merger had been consummated on January 1, 1996,
January 1, 1997 or June 30, 1997, respectively, nor is it necessarily
indicative of future operating results or financial position.
 
  The pro forma condensed consolidated financial statements should be read in
conjunction with the historical financial statements and the related notes
thereto of Ansan and Discovery included herein and Management's Discussion and
Analysis of Financial Condition and Plan of Operations.
 
                                      55

                    UNAUDITED PRO FORMA COMBINED CONDENSED
 
                                 BALANCE SHEET
                                 JUNE 30, 1997
                                (IN THOUSANDS)

                                                                          PRO FORMA
                               ANSAN       DISCOVERY    PRO FORMA         COMBINED
                          PHARMACEUTICALS LABORATORIES ADJUSTMENTS    REFLECTING MERGER
                          --------------- ------------ -----------    -----------------
                                                          
         ASSETS
         ------
Current assets
  Cash and cash
   equivalents..........     $    498       $ 1,478     $ (1,189)(A)       $   787
  Short-term
   investments..........        1,200        13,319          --             14,519
  Prepaid expenses and
   other current assets.           32            35          --                 67
                             --------       -------     --------           -------
    Total current
     assets.............        1,730        14,832       (1,189)           15,373
Furniture and equipment,
 net....................           88           115                            203
                             --------       -------     --------           -------
                             $  1,818       $14,947     $ (1,189)          $15,576
                             ========       =======     ========           =======
    LIABILITIES AND
  STOCKHOLDERS' EQUITY
- ------------------------
Current liabilities
  Accounts payable......     $    138       $   296     $    950 (C)       $ 1,384
  Payable to Titan
   Pharmaceuticals,
   Inc. ................          189           --          (189)(A)           --
  Accrued sponsored
   research.............          --            --           --                --
  Accrued legal fees....            6           --           --                  6
  Other accrued
   liabilities..........           11           --           --                 11
  Debenture payable to
   Titan
   Pharmaceuticals,
   Inc. ................        1,000           --        (1,000)(A)           --
                             --------       -------     --------           -------
    Total current
     liabilities........        1,344           296         (239)            1,401
Commitments
Minority Interest.......          --          2,200          --              2,200
Stockholders' Equity
  Preferred Stock.......                          2                              2
  Common Stock..........            3             7           (1)(B)             9
  Additional paid-in
   capital..............       10,697        18,992      (10,697)(B)        21,449
                                                           2,457 (B)
  Deficit accumulated         (10,226)       (6,550)      10,226 (B)        (9,485)
   during the
   development
   stage................                                  (2,935)(B)
                             --------       -------     --------           -------
    Total stockholders'
     equity.............          474        12,451         (950)           11,975
                             --------       -------     --------           -------
                             $  1,818       $14,947     $ (1,189)          $15,576
                             ========       =======     ========           =======

- --------
(A) Reflects the repayment of obligations to Titan Pharmaceuticals, Inc. in
    connection with the Merger.
 
(B) Reflects the allocation of the estimated purchase price of approximately
    $2.9 million to the historical Ansan balance sheet. The adjustment
    includes approximately $2.9 million of purchased in-process research and
    development. Also reflects the elimination of Ansan's stockholders' equity
    accounts.
 
(C) Reflects the estimated costs incurred by Ansan and Discovery to complete
    the Merger.
 
                                      56

                         UNAUDITED PRO FORMA COMBINED
                            STATEMENT OF OPERATIONS
 
                        SIX MONTHS ENDED JUNE 30, 1997
              (IN THOUSANDS, EXCEPT SHARE AND PER SHARE AMOUNTS)

                                                                         PRO FORMA
                               ANSAN       DISCOVERY    PRO FORMA        COMBINED
                          PHARMACEUTICALS LABORATORIES ADJUSTMENTS   REFLECTING MERGER
                          --------------- ------------ -----------   -----------------
                                                         
COSTS AND EXPENSES
  Research and
   development..........    $      627     $    2,257     $--           $    2,884
  General and
   administrative.......           529          1,345      --                1,874
                            ----------     ----------     ----          ----------
Loss from operations....        (1,156)        (3,602)     --               (4,758)
Other income/(expenses)
  Interest income.......            40            306      (23) (D)            323
  Interest expense......           (29)                     29 (D)             --
                            ----------     ----------     ----          ----------
Net loss................    $   (1,146)    $   (3,296)    $  6          $   (4,436)
                            ==========     ==========     ====          ==========
Net loss per share......    $    (0.46)    $    (0.42)                  $    (0.47)
                            ==========     ==========                   ==========
Shares used in computing
 net loss per share.....     2,484,937      7,836,363                    9,475,663
                            ==========     ==========                   ==========

- --------
(D) Reflects the net reduction of interest expense as a result of the
    repayment of the Titan Debenture in connection with the Merger
 
                                      57

                          UNAUDITED PRO FORMA COMBINED
                            STATEMENT OF OPERATIONS
 
                          YEAR ENDED DECEMBER 31, 1996
               (IN THOUSANDS, EXCEPT SHARE AND PER SHARE AMOUNTS)

                                                                       PRO FORMA
                               ANSAN       DISCOVERY    PRO FORMA      COMBINED
                          PHARMACEUTICALS LABORATORIES ADJUSTMENTS REFLECTING MERGER
                          --------------- ------------ ----------- -----------------
                                                       
Costs and expenses
  Research and
   development..........    $    1,181     $    2,740     $--         $    3,921
  General and
   administrative.......         1,257            692      --              1,949
                            ----------     ----------     ----        ----------
Loss from operations....        (2,438)        (3,432)     --             (5,870)
Other income/(expenses)
  Interest income.......           157            205      --                362
  Interest expense......                          (11)     --                (11)
                            ----------     ----------     ----        ----------
Loss before minority
 interest...............        (2,281)        (3,238)     --             (5,519)
Minority interest in
 loss of subsidiary.....           --               2      --                  2
                            ----------     ----------     ----        ----------
Net loss................    $   (2,281)    $   (3,236)    $--         $   (5,517)
                            ==========     ==========     ====        ==========
Net loss per share......    $    (0.94)    $    (0.65)                $    (0.84)
                            ==========     ==========                 ==========
Shares used in computing
 net loss...............     2,431,447      4,943,768                  6,583,068
                            ==========     ==========                 ==========

                                       58

                NOTES TO UNAUDITED PRO FORMA COMBINED CONDENSED
                             FINANCIAL STATEMENTS
 
NOTE 1
 
  The unaudited pro forma condensed combined balance sheet of Ansan and
Discovery has been prepared as if the Merger was completed as of June 30,
1997. The Merger will be accounted for as a purchase of Ansan by Discovery, as
Discovery's current stockholders will own approximately 92% of the merged
entity. Notwithstanding, Ansan will be the surviving corporate entity. The
total cost of the proposed merger is estimated to be approximately $2.9
million, including transaction cost incurred by Discovery of approximately
$450,000 which includes financial advisory, legal, and accounting fees.
 
  The purchase cost of Ansan has been determined based on the estimated fair
market value of Ansan stock. The estimated purchase price consists of the
following (in thousands):

                                                                  
     Estimated value of Common Stock to be held by current Ansan
      stockholders following the Merger (1,639,300 shares of Common
      Stock at $1.50 per share)..................................... $ 2,459
     Estimated transaction costs to be incurred by Discovery........     450
                                                                     -------
                                                                     $ 2,909
                                                                     =======
 
  Based on a preliminary analysis of tangible and intangible assets, the
allocation of the purchase price is as follows:
 
     Tangible assets of Ansan acquired.............................. $ 1,818
     In-process research & development..............................   2,935
     Liabilities of Ansan assumed (including transaction costs).....  (1,844)
                                                                     -------
                                                                     $ 2,909
                                                                     =======

  The in-process research and development will be charged against earnings.
Such charge has not been reflected in the pro forma condensed statement of
operations as such charge is a non-recurring charge directly attributable to
the Merger.
 
  The pro forma adjustments include accrued liabilities of $950,000 to reflect
the estimated costs incurred by both Ansan and Discovery to complete the
Merger.
 
  The pro forma adjustments include the repayment of approximately $1,200,000
in debt owed to Titan.
 
  No pro forma adjustment has been included to reflect the sale of shares of
Ansan Series A Preferred Stock to Discovery for $1,300,000 during July 1997,
as such Series A Preferred Stock will be cancelled upon the completion of the
Merger.
 
  No pro forma adjustment has been included to reflect the Titan Sublicense
Agreement, as there is no effect on the pro forma periods presented.
 
NOTE 2
 
  The unaudited pro forma condensed consolidated statements of operations of
Ansan and Discovery have been prepared as if the Merger was completed as of
January 1, 1996 and January 1, 1997 respectively. The condensed consolidated
statement of operations for the six months ended June 30, 1997, includes an
adjustment to reduce interest expense to reflect the repayment of the Titan
Debenture in connection with the Merger.
 
NOTE 3
 
  Combined pro forma net loss per share for the year ended December 31, 1996
and the six-month period ended June 30, 1997 is computed using the historical
weighted average number of Discovery Common Stock outstanding, adjusted for
the Common Exchange Ratio in the Merger, plus the 1,639,300 shares of Ansan
Common Stock outstanding following the cancellation of Titan's holding in
Ansan. Preferred stock and other common stock equivalents issued in the Merger
are not included, as their effect is antidilutive.
 
                                      59

                                     ANSAN
                    MANAGEMENT'S DISCUSSION AND ANALYSIS OF
                  FINANCIAL CONDITION AND PLAN OF OPERATIONS
 
RESULTS OF OPERATIONS
 
  Ansan is in the development stage. Since its inception in November 1992,
Ansan's efforts have been principally devoted to research and development,
securing patent protection and raising capital. From inception through June
30, 1997, Ansan has sustained cumulative losses of approximately $10,226,000.
These losses have resulted from expenditures in connection with research and
development and general and administrative activities, including legal and
professional activities.
 
  Through June 30, 1997, research and development expenses since inception
have been approximately $6,608,000 and general and administrative expenses
since inception have been approximately $3,443,000. Total research and
development expenses were approximately $244,000 and $627,000 during the
three- and six-month periods ended June 30, 1997, respectively, compared with
approximately $206,000 and $463,000 for the three- and six-month periods ended
June 30, 1996, respectively, an increase of approximately 18% and 35% for the
three- and six-month periods, respectively. The increases are due to
expenditures associated with the development initiatives for AN10 Topical and
Apafant. Such expenditures include, but are not limited to, formulation
development, chemistry, manufacturing and controls, pharmacology and
toxicology.
 
  Research and development expenses for 1996 were $1,181,000, as compared to
$1,421,000 for 1995, a decrease of $240,000, or 17%. The higher level of
expenditures in 1995 is attributed to costs incurred in anticipation of
Ansan's clinical trial that commenced in the first quarter of 1996. These
costs included expenditures for preparation and compilation of the IND,
toxicology studies and manufacturing. Also, during the second of half of 1995,
Ansan reorganized much of its research and development activities that are
performed by outside vendors by establishing new vendor relationships, and
moving certain functions in-house. This reorganization has resulted in a cost
savings to Ansan.
 
  Total general and administrative expenses were approximately $257,000 and
$529,000 during the three- and six-month periods ended June 30, 1997,
respectively, compared with approximately $242,000 and $442,000 for the three-
and six-month periods ended June 30, 1996, respectively, an increase of
approximately 6% and 20% for the three- and six-month periods, respectively.
The increase is due to additional overhead needed to support Ansan's
additional development programs.
 
  General and administrative expenses for 1996 were $1,257,000, as compared to
$1,048,000 for 1995, an increase of $209,000, or 20%. The increase can be
attributed to an issuance of stock to a member of management, a portion of
which was allocated to general and administrative expenses. In addition, the
1996 expenses reflect post-initial public offering ("IPO") expenditures such
as investor relations and directors and officers insurance.
 
  Interest income was approximately $21,000 and $40,000 for the three- and
six-month periods ended June 30, 1997, respectively, compared with
approximately $44,000 and $93,000 for the three- and six-month periods ended
June 30, 1996. This decrease is the result of declining cash balances. Ansan
has also incurred interest expense of approximately $29,000 for the six months
ended June 30, 1997, related to the $1,000,000 note payable to Titan (see
"Liquidity and Capital Resources"). Ansan had no interest bearing debt for the
comparable period in 1996.
 
  Other income includes interest income of $158,000 during 1996 as compared to
$78,000 during 1995. The increase was a result of a substantial increase in
the amount of cash and short-term investments subsequent to Ansan's IPO in
August 1995. Interest expense was $431,000 during 1995 which included a non-
cash charge of $400,000 relating to a discount attributed to Class A Warrants
issued in a bridge financing of debt securities prior to Ansan's IPO.
 
  Ansan expects to continue to incur substantial research and development
costs in the future due to ongoing and new research and development programs,
manufacturing of products for use in clinical trials, patent and regulatory
activities, and preclinical and clinical testing of Ansan's products. In May
1996, Ansan signed the
 
                                      60

Boehringer Ingelheim License Agreement with Boehringer Ingelheim to acquire
the rights in the United States and the European Union to develop a new
intravenous formulation of the drug Apafant for all clinical indications.
Ansan expects to incur substantial research and development costs related to
this acquisition. Ansan also expects that general and administrative costs
necessary to support clinical trials, research and development, manufacturing
and the creation of a marketing and sales organization, if warranted, will
increase in the future. Accordingly, Ansan expects to incur increasing
operating losses for the foreseeable future. There can be no assurance that
Ansan will ever achieve profitable operations.
 
  Ansan's business is subject to significant risks including, but not limited
to, the success of its research and development efforts, obtaining and
enforcing patents important to Ansan's business, competition from other
products and a lengthy and expensive regulatory approval process. It is not
anticipated that Ansan will have the resources necessary to conduct the
several phases of clinical testing in human subjects necessary to complete
development and to commercialize any products absent the Merger. In the event
the Merger is not consummated, Ansan's strategy will be to continue to seek
public or private financing through the sale of securities or corporate
partnering arrangements. There can be no assurance that financing from such
sources or others will be available. Additional expenses, delays, or losses of
opportunity that may arise out to these and other risks could have a material
adverse impact on Ansan's financial condition and results of operations.
 
LIQUIDITY AND CAPITAL RESOURCES
 
  In August and September 1995, Ansan completed an IPO which resulted in net
proceeds to Ansan, after deduction of underwriting discounts and commissions
and other expenses of the IPO, of approximately $5,950,000. As of June 30,
1997, Ansan had working capital of approximately $386,000.
 
  In March 1997, Ansan and Titan entered into an agreement for financing
pursuant to which Titan advanced Ansan $1,000,000 in return for a debenture
(the "Debenture") which was convertible at any time prior to June 21, 1997
into 333,333 shares of common stock. Titan did not convert the Debenture prior
to June 21, 1997. The Debenture bears interest at prime plus 2% and is due in
April 1998. In connection with the issuance of the Debenture, Ansan granted
Titan an option to acquire an additional 333,333 shares of Ansan Common Stock
for an aggregate purchase price of $1,000,000. The option expired unexercised
on June 21, 1997.
 
  In July of 1997 Ansan entered into the Merger Agreement with Discovery. The
parties also entered into the Series A Purchase Agreement pursuant to which
Discovery purchased Ansan Series A Preferred Stock for aggregate cash
consideration of $1,300,000, representing a common stock equivalent price of
approximately $1.40 per share.
 
  As a condition to closing the Merger, the stock of Ansan held by Titan will
be cancelled and the Debenture and interest thereon, and certain liabilities
of Ansan with respect to services provided by Titan, will be repaid by Ansan.
Additionally, effective upon the closing of the Merger, Titan and Ansan will
enter into the Titan Sublicense Agreement, pursuant to which Ansan will grant
Titan a sublicense to the family of compounds licensed to Ansan under the Bar-
Ilan License Agreement for certain indications. See "Information Concerning
Ansan--Relationship with Titan Pharmaceuticals, Inc."
 
  Ansan expects to continue to incur substantial additional operating losses
from costs related to continuation and expansion of research and development,
clinical trials, and increased administrative and fundraising activities over
at least the next several years. While Ansan believes that its current capital
resources will be sufficient to sustain its planned operations for
approximately one year, Ansan will be required to seek additional financing to
continue its activities beyond that period. However, Ansan's capital
requirements may change depending on numerous factors including, but not
limited to, the progress of research and development programs, the results of
clinical studies, the timing of regulatory approvals, technological advances,
determinations as to the commercial potential of Ansan's products, and the
status of competitive products. In addition, expenditures will be dependent
upon the establishment of collaborative relationships with other companies,
the availability of financing, and other factors. In any event, Ansan
anticipates that it will require substantial additional financing in the
future. There can be no assurance as to the availability or terms of any
required additional financing, when and if needed. In the event that Ansan
fails to raise any funds it requires, it may be necessary for Ansan to out-
license rights it would prefer to retain, or to significantly curtail its
activities or cease operations.
 
                                      61

                                   DISCOVERY
                    MANAGEMENT'S DISCUSSION AND ANALYSIS OF
                  FINANCIAL CONDITION AND PLAN OF OPERATIONS
 
GENERAL
 
  Discovery was originally organized as MicroBio, Inc. on May 18, 1993.
Discovery had limited operations prior to January 1995. In May 1996, Discovery
amended its Certificate of Incorporation to effect a name change to its
current name, Discovery Laboratories, Inc. In April 1996, Discovery entered
into a three-year employment agreement with James S. Kuo, M.D., whereby Dr.
Kuo agreed to serve as President and Chief Executive Officer of Discovery. In
October 1996, ATI entered into a four-year employment agreement with Robert J.
Capetola, Ph.D., whereby Dr. Capetola became the President, Chief Executive
Officer and Chairman of the Board of ATI.
 
  Since its inception, Discovery has concentrated its efforts and resources in
the development and commercialization of pharmaceutical products and
technologies. Discovery has been unprofitable since its founding and has
incurred a cumulative net loss of approximately $6,550,000 as of June 30,
1997. Discovery expects to incur significantly increasing operating losses
over the next several years, primarily due to the expansion of its research
and development programs, including clinical trials for the SuperVent(TM) and
ST-630 products, the KL4-Surfactant technology and other products and
technologies that it may acquire or develop. Discovery's ability to achieve
profitability depends upon, among other things, its ability to discover and
develop products, obtain regulatory approval for its proposed products, and
enter into agreements for product development, manufacturing and
commercialization. None of Discovery's products currently generate revenues
and Discovery does not expect to achieve revenues for the foreseeable future.
Moreover, there can be no assurance that Discovery will ever achieve
significant revenues or profitable operations from the sale of the
SuperVent(TM) and ST-630 products, the KL4-Surfactant technology or any other
products or technologies that it may acquire or develop. See "Risk Factors--
Development Stage of Discovery and Ansan; No Developed or Approved Products;
Uncertainty of Future Profitability."
 
PLAN OF OPERATION
 
  Discovery is currently engaged in the development and commercialization of
investigational drugs that have previously been tested in humans or animals.
In March 1996, Discovery executed a license agreement with The Charlotte-
Mecklenburg Hospital Authority ("CMHA") as owner and licensor of Discovery's
tyloxapol patents and patent applications. Discovery paid $86,400 as a license
issue fee to CMHA to obtain its license. In September 1996, Discovery entered
into a license agreement (the "WARF License Agreement") with the Wisconsin
Alumni Research Foundation ("WARF") relating to an active vitamin D analog,
ST-630, and its potential use in treating postmenopausal osteoporosis.
Discovery paid a $400,000 initial fee to WARF upon execution of the WARF
License Agreement and is responsible for an additional milestone payment and
royalties pursuant to such agreement. In October 1996, ATI executed a
sublicense agreement with J&J and J&J's wholly-owned subsidiary, Ortho
Pharmaceutical Corporation, granting an exclusive sublicense of the KL4-
Surfactant technology to ATI in exchange for an initial $200,000 license fee,
additional milestone payments, royalties and common stock of ATI. J&J
contributed its existing KL4-Surfactant raw material inventory and specialized
manufacturing equipment to ATI in exchange for shares of nonvoting Series B
Preferred Stock of ATI having a $2.2 million liquidation preference.
 
  Discovery anticipates that during the next 12 months it will conduct
substantial research and development of the SuperVent(TM), KL4-Surfactant and
ST-630 products, including, without limitation, a Phase I/II clinical trial of
SuperVent(TM) for the treatment of CF that was commenced on March 17, 1997 and
Phase II clinical trials of KL4-Surfactant for the treatment of MAS and ARDS.
Discovery also intends to initiate clinical studies of ST-630 as a once-daily,
orally administered drug for the treatment of postmenopausal osteoporosis in
the United States during the next 12 months. Certain of the planned clinical
trials of Discovery's products in development require the receipt of FDA
approvals, and there can be no assurance as to the receipt or the timing of
receipt of such approvals. See "Information Concerning Discovery--Products and
Technologies Under Development," and
 
                                      62

"--Government Regulation; Orphan Drug Designation." Discovery may seek to
acquire additional products and technologies in the future. Should Discovery
acquire such additional products or technologies, it is anticipated that such
additional products or technologies will require substantial resources for
research, development and clinical evaluation. However, there can be no
assurance that Discovery will be able to obtain the additional financing
necessary to acquire and develop such products and technologies. Furthermore,
there can be no assurance that changes in Discovery's research and development
plans or other changes which would or could alter Discovery's operating
expenses will not require Discovery to reallocate funds among its planned
activities and curtail certain planned expenditures. In such event, Discovery
may need additional financing. There can be no assurance as to the
availability or the terms of any required additional financing, when and if
needed. In the event that Discovery fails to raise any funds it requires, it
may be necessary for Discovery to significantly curtail its activities or
cease operations.
 
  Discovery has recently hired six new employees to serve as Vice President of
Regulatory Affairs, Director of Business Development and Project Manager,
respectively, of Discovery, and Vice President of Biometrics, Vice President
of Clinical Research and Director of Clinical Research of ATI. The timing and
cost of hiring any additional employees may vary depending on need and cannot
currently be predicted with any certainty.
 
  ATI has entered into an agreement with Cook Imaging Corporation for the
development of the manufacturing process to be employed in the KL4-Surfactant
program. It is also anticipated that, over the next 12 months, ATI will enter
into an agreement with a third party for the purpose of supplying KL4-
Surfactant to ATI. No specific supplier has been identified to date.
 
LIQUIDITY AND CAPITAL RESOURCES
 
  Discovery anticipates that its current resources will permit it to meet its
business objectives until approximately June, 1998 absent the Merger.
Discovery's working capital requirements will depend upon numerous factors,
including, without limitation, progress of Discovery's research and
development programs, preclinical and clinical testing, timing and cost of
obtaining regulatory approvals, levels of resources that Discovery devotes to
the development of manufacturing and marketing capabilities, technological
advances, status of competitors, and abilities of Discovery to establish
collaborative arrangements with other organizations, and as such there can be
no assurance that Discovery will not be required to raise additional capital
prior to June, 1998 (or earlier, in the event the Merger is consummated) or,
in general, that Discovery will be able to achieve its business objectives.
Pursuant to a private placement conducted during June through November 1996,
Discovery raised approximately $19,000,000 in net proceeds through the sale of
units consisting of Discovery Common Stock and Discovery Series A Preferred
Stock. The reduction of Discovery's current assets (excluding prepaid
expenses) to approximately $14.8 million at June 30, 1997, reflects the use of
cash in the course of Discovery's and ATI's research initiatives described
under "Information Concerning Discovery".
 
ABSENCE OF MARKET; RESTRICTED SECURITIES
 
  To date there has been no public market for securities of Discovery. As of
July 31, 1997 there were approximately 255 stockholders of Discovery of
record, and 6,747,256 shares of Discovery Common Stock and 2,200,256 shares of
Discovery Series A Preferred Stock were issued and outstanding. Reserved
shares of Discovery at June 30, 1997 include: (i) 8,801,024 shares of
Discovery Common Stock issuable upon conversion of Discovery Series A
Preferred Stock; (ii) 1,100,130 shares of Discovery Common Stock issuable upon
exercises of Discovery's outstanding warrants and upon conversion of preferred
stock subject to such warrants; and (iii) 1,250,000 shares of Discovery Common
Stock reserved for issuance pursuant to Discovery's 1996 Stock Option Plan
(the "Discovery Option Plan"), of which options to purchase a total of 661,500
shares of Discovery Common Stock were outstanding. The terms of the Discovery
Option Plan allow outstanding options to be assumed by a successor company in
a transaction such as the Merger. The Discovery Warrants will be assumed by
Ansan upon consummation of the Merger. See "Discovery Stock Options and
Warrants".

                                      63

  Discovery believes that the 6,747,256 outstanding shares of Discovery Common
Stock are "restricted securities" and under certain circumstances may, in the
future, be sold in compliance with Rule 144 under the Securities Act, unless
they are held by "affiliates" of Discovery (as that term is used under the
Securities Act). Assuming the availability of Rule 144, Discovery believes
that of the 6,747,256 "restricted" shares of Discovery Common Stock,
approximately 5,140,732 shares of Discovery Common Stock are eligible for sale
and an additional approximately 1,477,524 shares of Discovery Common Stock
will be eligible for sale beginning in October 1997 pursuant to Rule 144, so
long as there is adequate current public information with respect to Discovery
as contemplated by Rule 144, as well as, certain volume limitations and manner
of sale requirements imposed by Rule 144.
 
                                      64

                         INFORMATION CONCERNING ANSAN
 
GENERAL
 
  Ansan is a development stage pharmaceutical company engaged in the
acquisition and further development of drugs intended to treat serious medical
conditions including pancreatitis, cancer and cancer-related conditions, blood
disorders and other life-threatening diseases for which therapies are not yet
available or current therapies are not highly efficacious. Ansan in-licenses
drug candidates that have progressed beyond the initial discovery stage of
development. Such potential products have already undergone preclinical
toxicity testing and have demonstrated relevant biological activity in animal
experiments. Ansan believes that acquiring products that have already met or
surpassed these preliminary development hurdles can reduce product development
times and increase the probability of ultimate commercialization compared to
untested drug candidates emerging from initial discovery efforts.
 
  Ansan's development activities have historically been devoted to product
candidates within two principal categories. The first consists of a class of
novel synthetic analogs of butyric acid licensed from Bar-Ilan pursuant to the
Bar-Ilan License Agreement. Pursuant to the Titan Sublicense Agreement, the
butyrate analogs currently under development for oncological indications will
be sublicensed to Titan, and the butyrate analogs under development for beta-
hemoglobinopathies and certain other indications will be retained by Ansan.
The second category is the platelet activating factor antagonist Apafant.
Ansan has licensed from Boehringer Ingelheim the rights in the United States
and the European Union to develop an intravenous formulation of the drug
Apafant for all clinical indications other than asthma. Ansan is currently
developing an injectable form of Apafant for the treatment of patients with
acute pancreatitis.
 
RELATIONSHIP WITH TITAN PHARMACEUTICALS, INC.
 
  Ansan was founded as a wholly-owned subsidiary of Titan, a biopharmaceutical
company engaged, through the operations of its subsidiaries and affiliates, in
the development of new proprietary therapeutic products for use in the fields
of cancer, immunology, viral diseases, and disorders of the central nervous
system. After Ansan's initial public offering, Titan's ownership in Ansan was
reduced to 43%, and as of July 31, 1997, Titan owned approximately 32% of the
issued and outstanding shares of Ansan Stock (on an as-converted basis).
 
  Drs. Rosenwald and Bucalo serve as directors of Ansan and Titan. Since
Ansan's inception, Titan has from time to time provided certain executive,
administrative, financial, business development and regulatory services to
Ansan. Currently, Titan performs certain administrative and financial services
for Ansan in exchange for a monthly fee of approximately $5,000. It is not
expected that such arrangements will continue following the Effective Time.
 
  In March 1997, Ansan entered into a financing agreement with Titan. The
agreement included an initial payment to Ansan of $1,000,000 in exchange for
the Debenture, which was convertible at any time prior to June 21, 1997 into
333,333 shares of Ansan Common Stock. Titan did not convert the Debenture
prior to the expiration of such conversion option. The Debenture bears
interest at prime plus 2% and is due in April 1998. Discovery's obligation to
consummate the Merger is conditioned upon repayment of the Debenture by Ansan.
 
  As noted above, effective upon closing of the Merger, Ansan will grant to
Titan certain rights to the family of compounds licensed under the Bar-Ilan
License Agreement. To date, Ansan has pursued development of two compounds,
AN9 and AN10, pursuant to the Bar-Ilan License. Titan's rights to Pivanex(TM),
an injectable form of AN9, will include all indications except beta-
hemoglobinopathies. Titan's rights to the topical form of AN9 will be limited
to its use for the treatment of cutaneous cancers. Ansan will also license to
Titan rights to AN10 Injection for treatment of cancer. Under the terms of the
Titan Sublicense Agreement, Titan will pay Ansan a royalty of 2% of net sales
of the licensed products and all of the Ansan Common Stock held by Titan will
be surrendered to Ansan. Additionally, upon closing of the Merger, Ansan will
repay the Debenture, including accrued interest, and amounts outstanding for
administrative services performed by Titan.
 
                                      65

APAFANT INJECTION
 
  Apafant is a receptor antagonist of the proinflammatory mediator, platelet
activating factor (PAF). Ansan licensed the intravenous dosage form of Apafant
from Boehringer Ingelheim who evaluated oral and nasal dosage forms of this
drug in clinical trials in the United States, Europe, and Japan, primarily for
treatment of allergic rhinitis and asthma. Ansan is pursuing a development
program for an intravenous form of Apafant for the treatment of patients with
acute pancreatitis. Currently, no FDA-approved therapy is available for
treatment of these patients.
 
  Acute pancreatitis is an inflammatory process of the pancreas that may lead
to dysfunction or failure of other organ systems. The pancreatic inflammation
itself is clinically characterized by abdominal pain and is often accompanied
by vomiting, fever, tachycardia, leukocytosis and elevated pancreatic enzyme
levels in the blood and/or urine. The causes of acute pancreatitis include
gallstones, alcohol abuse, surgery, drugs, trauma, infection and others. The
incidence of acute pancreatitis in the United States is estimated to be
approximately 130,000 cases annually, with an overall mortality rate of 10-
20%. The greatest morbidity and the majority of the deaths from acute
pancreatitis are associated with multiple organ system failure (MOSF).
Pancreatitis and MOSF can involve pulmonary dysfunction (including acute
respiratory distress syndrome), renal dysfunction (including acute renal
failure), hepatic dysfunction, cardiovascular compromise, CNS depression,
coagulopathy and gastrointestinal bleeding.
 
  Abnormal levels of cytokines and inflammatory mediators such as PAF are
observed in acute pancreatitis and are now believed to be important factors in
the pathogenesis of MOSF. PAF is a potent proinflammatory substance produced
in the body whose role in pancreatitis, and in other conditions associated
with MOSF, has been extensively studied. The pancreas itself can release PAF,
and various toxins can induce PAF release and pancreatic inflammation
simultaneously. Administration of exogenous PAF in animal models can directly
stimulate pancreatic enzyme secretion and can induce pancreatitis. Treatment
with PAF antagonists in animal models of pancreatic injury has been shown to
reduce the release of pancreatic enzymes and reduce inflammation.
 
  Apafant has been experimentally shown favorably to affect tissue metabolism,
protect organs against damage, and decrease mortality in a variety of
experimental models of multiple organ system failure or dysfunction. These
include traumatic shock, hemorrhagic shock, Gram-positive shock, Gram-negative
sepsis, endotoxic shock, intestinal ischemia-reperfusion, and anaphylaxis.
Apafant also has protective effects in other experimental models involving
injury to the central nervous system or the kidney. Such findings of end-organ
protection by a potent PAF antagonist suggest that Apafant is a good candidate
to be tested for therapeutic efficacy in patients with acute pancreatitis who
are at significant risk for organ failure or dysfunction.
 
  Ansan met with the FDA on November 7, 1996 for a pre-IND meeting to discuss
its plans to study Apafant Injection for the treatment of patients with acute
pancreatitis. Ansan filed an IND on September 9, 1997 to initiate a Phase
Ib/II clinical trial in patients with acute pancreatitis. Based on the
discussion with the FDA, this IND calls for initiation of testing in patients
with mild acute pancreatitis. In order to identify clinical endpoints for
future trials, patients with severe disease would be enrolled in the second
part of the study. To support its IND, Ansan is relying on preclinical and
clinical safety data provided by Boehringer Ingelheim that were obtained with
the oral and nasal forms of Apafant for other indications. There is no
assurance that upon review of the IND, the FDA will approve Ansan's plans to
include patients with severe acute pancreatitis in the planned two-part study,
nor is there any assurance that the FDA will agree that the dose levels
selected by Ansan for the first study are acceptable. Clinical development of
the drug would incur significant delays if the FDA were to restrict the first
study to patients with mild disease or were to require the use of lower doses.
 
AN10 TOPICAL
 
  AN10 is a novel analog of butyric acid. Ansan is pursuing a development
program with AN10 Topical for the prevention of chemotherapy-induced alopecia
(hair loss). There is currently no FDA-approved therapy for the prevention of
alopecia in cancer patients.
 
                                      66

  Cytotoxic chemotherapy can damage or kill young and rapidly proliferating
cells, whether the cells are cancerous or normal. As a consequence, cells at
the base of hair follicles, which grow rapidly, are particularly susceptible
to cytotoxic injury. Although adjustments in chemotherapeutic dosing regimens
can sometimes mitigate these adverse effects, injury to such normal cells is
still common. Such injury to normal follicles may cause the transient or
permanent loss of hair. For many patients with cancer, this particular
physical change is associated with significant anxiety and stress. Ansan
believes that a new therapeutic agent that could protect hair follicles
against chemotherapy-induced damage would be beneficial to such patients.
 
  The butyrates have been extensively studied and are known to induce
differentiation and to alter the process of maturation in certain cell lines.
Butyrates have been shown to arrest cells in early phases of division, to
inhibit cell growth, and to induce synthesis of various proteins including
hemoglobin. Administration of an agent that could modulate cellular maturation
or growth rates might protect such cells against the ill effects routinely
caused by exposure to cytotoxic chemotherapeutic drugs.
 
  AN10 is more lipophilic than butyric acid and is therefore more easily
absorbed into cells. In various cell lines, AN10 has been shown to induce
differentiation, inhibit proliferation, and enhance the production of fetal
hemoglobin. AN10 also has shown activity in an established animal model of
cyclophosphamide-induced injury to the hair follicle. Administration of
cyclophosphamide in this model causes damage to the hair follicles resulting
in hair loss and subsequently delaying regrowth of hair. In contrast, animals
pretreated topically with AN10, prior to administration of cyclophosphamide,
maintained a much more normal rate and pattern of regrowth. Examination of
cutaneous histopathology specimens revealed that normal hair follicles were
virtually absent for 9-14 days after exposure to cyclophosphamide in the
cyclophosphamide-only group, whereas follicles were preserved and were
fundamentally normal in appearance in the group receiving both
cyclophosphamide and AN10 Topical.
 
  These findings suggest that AN10 Topical applied to the skin prior to
systemic exposure to cyclophosphamide may protect hair follicles against
cytotoxic injury. These positive findings, while compatible with an
enhancement of differentiation and induced maturation, do not conclusively
demonstrate that these are the mechanisms by which follicular protection has
been effected. While protection has been demonstrated in this model, the
precise mechanisms may remain uncertain until additional studies have been
completed. It is also uncertain whether or not AN10 Topical can protect hair
follicles from damage induced by chemotherapeutic agents other than
cyclophosphamide.
 
  In November 1996, Ansan filed a patent application with the PTO for a method
of using butyric acid analogs for the prevention of chemotherapy-induced
alopecia. Review by the PTO has not been completed.
 
  Ansan met with the FDA on February 10, 1997 for a pre-IND meeting to discuss
studying the topical form of AN10 for the prevention of chemotherapy-induced
alopecia in cancer patients. The next step would be to file an IND and
following receipt of FDA approval, if granted, to initiate a Phase I trial to
assess the safety of a single dose of AN10 Topical administered to normal
volunteers. There can be no assurance that such approval would be granted.
Assuming that acceptable safety of AN10 is demonstrated in this first study,
Ansan would need to complete additional preclinical studies before it would be
able to initiate repeated dose clinical trials in cancer patients receiving
chemotherapy. These preclinical studies include repeated dose toxicity studies
in two animal species as well as pharmacokinetic studies. There can be no
assurance that the current formulation of AN10 Topical would be found to have
acceptable safety in either the preclinical studies or the first clinical
trial in order to enable testing in patients.
 
NOVAHEME(TM) INJECTION
 
  Novaheme(TM) Injection is an intravenous form of AN10 that Ansan is
developing for the treatment of Beta-hemoglobinopathies. Beta-
hemoglobinopathies are genetic disorders that impair a person's ability to
produce adult hemoglobin ("HbA"), the oxygen-carrying protein of red blood
cells. The most common of the beta-hemoglobinopathies are beta-thalassemia and
sickle-cell anemia. In normal adults, HbA comprises more than 99% of
hemoglobin. Patients suffering from beta-thalassemia produce little or no HbA,
while those with
 
                                      67

sickle-cell anemia produce structurally dysfunctional HbA. Complications of
sickle-cell anemia include stroke, aplastic crisis, pain and swelling,
bacterial infections and organ damage. Currently, medical efforts to treat
sickle-cell anemia are directed towards treating the symptoms in acute crises
and prevention of respiratory infections. Patients with severe symptoms may
require several hospitalizations a year. Patients with beta-thalassemia
require transfusions to sustain life, but the onset of iron overload may
result in disability or death in many patients by early adulthood. To date, no
effective conventional therapy exists for beta-thalassemia, and treatment is
limited to management of symptoms and complications of both the disease and
its treatments.
 
  Limited clinical studies have demonstrated that agents which increase levels
of fetal hemoglobin ("HbF") appears to reduce disease symptoms in patients
with sickle-cell anemia. Whether the change in HbF levels is the proximate
cause of, or in any way a contributing factor to, the reduction in symptoms is
not certain. In laboratory tests, Novaheme appears to markedly increase levels
of HbF expression, as well as the percentage of blood cells that express HbF,
and is distributed widely when given intravenously, with certain dosing
regimens. In addition, ex vivo studies conducted on a human red blood cell
line have shown Novaheme to be more potent than unmodified butyric acid,
hydroxyurea, and isobutyramide in increasing HbF levels. While these results
are encouraging, there can be no assurance that ex vivo increases in HbF will
predict similar changes in vivo, resulting in an improvement in symptoms of
benefit to patients.
 
  Bar-Ilan was recently awarded United States Patent No. 5,569,675 covering
the use of Novaheme Injection for the treatment of serious blood disorders
such as sickle cell disease or beta-thalassemia. Ansan is currently seeking a
development partner for this product. There can be no assurance that Ansan
will be successful in identifying a suitable partner.
 
PIVANEX(TM) INJECTION
 
  Pivanex(TM) Injection is an injectable form of AN9, another novel analog of
butyric acid. Ansan is pursuing a development program for the use of
Pivanex(TM) Injection to treat patients with cancer.
 
  Cells change as they mature and differentiate, that is, reach their final
shape, size and function. Cancer cells, however, often tend to be relatively
immature or undifferentiated, which may lead to unregulated growth. Unlike
traditional cytotoxic chemotherapy, "differentiation therapy" represents a
relatively new direction in cancer research. It involves the development of
agents that, in contrast to the function of cytotoxic agents, induce cancer
cells to differentiate, mature and exhibit more normal growth properties.
Differentiation therapy may also lead to apoptosis, or what is known as normal
"programmed cell death," resulting in the destruction of the cancer cells
while, it is believed, sparing normal cells (whether or not they are rapidly
dividing). However, there can be no guarantee that any putative apoptotic
agent will ultimately prove to be as broadly efficacious across different
types of tumors as cytotoxic agents have proven to be in the past.
 
  In animal studies, Pivanex(TM) Injection has demonstrated a reduction in
metastatic spread of cancer cells, without unacceptable in vivo toxicity.
Furthermore, in vitro studies have shown anticancer activity of Pivanex(TM)
Injection against a broad range of animal cancer cell lines (lung, skin, white
blood cell) and against certain human cancer cell lines (breast, ovarian,
lung, colon and pancreatic cancers and melanoma). Positive results have been
observed in certain in vivo animal studies as well although not in all models.
Taken together, the data suggest that Pivanex(TM) Injection development
efforts could potentially result in an effective anticancer therapeutic agent
with low toxicity. Clinical test of Pivanex(TM) Injection in cancer patients
began in January 1996 pursuant to an IND approved by the FDA.
 
  Animal data generated in parallel with the current clinical study of
Pivanex(TM) Injection have suggested that when Pivanex(TM) Injection is
administered by vein the highest concentrations of drug may be available to
treat tumors that are located in the lungs. Substantially less drug is
available after intravenous administration to treat tumors located outside of
the lung. As a consequence of these findings, an effort has been made to
enroll patients with lung cancer in the current clinical study. Ansan
submitted an interim safety analysis of the current Pivanex(TM) Injection
clinical study to the FDA in March 1997. Twelve patients had been enrolled and
no drug-related serious
 
                                      68

adverse events had been reported. Of the twelve patients, five had lung
cancer. The other seven patients enrolled previously had cancers located in
sites other than the lungs (such as the colon or liver), and there was no
objective evidence of response to treatment in these seven patients.
 
  In one patient with squamous cell carcinoma lung cancer, enrolled in August
1996, there was approximately a 50% reduction in the tumor volume, as measured
by an x-ray technique known as computerized tomography, after two courses of
Pivanex(TM) Injection. A repeat x-ray after the fourth course showed no
further decrease in tumor size. The patient was removed from the study to
undergo another therapy for an unrelated medical condition. While off-study,
the patient developed an additional lesion in the lung which was confirmed to
be squamous cell carcinoma upon biopsy in January 1997. The patient was re-
started on Pivanex(TM) Injection at a higher dose, and this new lesion was no
longer apparent on x-ray after six courses of Pivanex(TM) Injection at the
higher dose.
 
  Ansan and the principal investigator of the clinical trial find this
reported result encouraging. There can be no assurance, however, that the
observed shrinkage of the tumor resulted from the administration of
Pivanex(TM) Injection, can be maintained for any meaningful duration or can be
reproduced in other patients. Substantial additional clinical testing will be
required to establish and verify the safety and efficacy of Pivanex(TM)
Injection. These trials will require at least two or more years to complete,
and there can be no assurance that such trials will result in the regulatory
approval required for the commercialization of Pivanex(TM) Injection.
 
  Under the terms of the Titan Sublicense Agreement, Ansan will grant rights
to Pivanex(TM) Injection to Titan. See "Information Concerning Ansan--
Relationship with Titan Pharmaceuticals, Inc."
 
AN9 TOPICAL
 
  Ansan is also pursuing a topical form of AN9. It has been previously shown
in laboratory testing that direct application of a formulation of AN9 to human
melanoma cells can inhibit growth of this type of cancer. Pursuant to this
observation, Ansan has been performing certain experiments to enable the
filing of an IND for AN9 Topical. Ansan has met with the FDA regarding such an
effort. As a result, Ansan may decide to file an IND to proceed with clinical
testing of AN9 Topical in the future. However, Ansan must complete certain
additional toxicology studies before an IND can be submitted, and there can be
no assurance that these studies can be concluded successfully or in a timely
manner. Accordingly, there can be no assurance that the IND will be filed in a
timely manner or at all and no assurance that the FDA will ultimately approve
the IND if one is filed.
 
  Under the terms of the Titan Sublicense Agreement, Ansan will grant rights
to AN9 Topical for oncologic disorders to Titan. See "Information Concerning
Ansan--Relationship with Titan."
 
LICENSE AGREEMENTS
 
  Ansan has obtained from Bar-Ilan an exclusive worldwide license, pursuant to
the Bar-Ilan License Agreement, to a United States patent and corresponding
foreign patents and patent applications covering AN9 and other butyric acid
analogs, and a United States patent directed to the use of AN10 and other
butyric acid analogs to treat beta-hemoglobinopathies. The Bar-Ilan License
Agreement provides for the payment by Ansan to Bar-Ilan of royalties based on
sales of products and processes incorporating the licensed technology, subject
to minimum annual amounts which commenced in 1995, as well as a percentage of
any income derived from any sublicense of the licensed technology. Ansan must
also pay all costs and expenses incurred in patent prosecution and maintenance
(although Titan will assume certain such obligations pursuant to the Titan
Sublicense Agreement in the event the Merger is consummated). The minimum
annual royalty for 1996 was $15,000, and will increase annually. The minimum
annual royalty will be $20,000 and $25,000 for 1997 and 1998 respectively and
$60,000 per annum for 1999 and beyond.
 
  In May of 1996, Ansan signed the Boehringer Ingelheim License Agreement with
Boehringer Ingelheim to acquire the rights in the United States and the
European Union to develop a new intravenous formulation of Apafant for all
clinical indications other than asthma. Pursuant to the agreement, Ansan may
be obligated to
 
                                      69

make future milestone and royalty payments to Boehringer Ingelheim. However,
Boehringer Ingelheim has the right to acquire these rights to Apafant for a
fee and thereafter develop and commercialize Apafant. In such circumstances,
Boehringer Ingelheim would be obligated to make milestone and royalty payments
to Ansan.
 
  Ansan must also satisfy the terms and conditions set forth in the Bar-Ilan
License Agreement and the Boehringer Ingelheim License Agreement in order to
retain its license rights thereunder, including but not limited to diligent
pursuit of product development and the timely payment of royalty fees. If
Ansan fails to comply with such terms and conditions as set forth in the Bar-
Ilan License Agreement or the Boehringer Ingelheim License Agreement, its
rights thereunder for individual product opportunities could be terminated.
 
SCIENTIFIC ADVISORS
 
  Since Ansan's inception, Ansan has sought the advisory services of a number
of scientists, researchers and clinicians with extensive experience in Ansan's
fields of interest (the "Scientific Advisors"). The Scientific Advisors have
assisted Ansan in identifying scientific and product development
opportunities, in reviewing and evaluating with management the progress of
research programs, and in recruiting and evaluating scientists and other
employees. It is expected that the Scientific Advisors will continue to meet
with management and key scientific employees of Ansan in groups or
individually on an informal basis.
 
PATENTS AND PROPRIETARY RIGHTS
 
  Ansan's success will depend, in part, on its ability, and the ability of its
licensor(s), to obtain protection for its products and technologies under
United States and foreign patent laws, to preserve its trade secrets, and to
operate without infringing the proprietary rights of third parties. Ansan has
obtained rights to certain patents and patent applications and may, in the
future, seek rights from third parties to additional patents and patent
applications. There can be no assurance that patent applications relating to
Ansan's potential products which have been licensed by Ansan from Bar-Ilan, or
that it may license from others in the future, will result in patents being
issued, that any issued patents will afford adequate protection to Ansan or
not be challenged, invalidated, infringed or circumvented, or that any rights
granted thereunder will afford additional competitive advantages to Ansan.
Furthermore, there can be no assurance that others have not independently
developed, or will not independently develop, similar products and/or
technologies, duplicate any of Ansan's products or technologies, or, if
patents are issued to, or licensed by, Ansan, design around such patents.
There also can be no assurance that the validity of any of the patents
licensed to Ansan would be upheld if challenged by others in litigation or
that Ansan's activities would not infringe patents owned by others. Ansan
could incur substantial costs in defending itself in suits brought against it
or any of its licensors, or in suits in which Ansan may assert, against
others, patents in which Ansan has rights. Should Ansan's products or
technologies be found to infringe patents issued to third parties, the
manufacture, use, and sale of Ansan's products could be enjoined and Ansan
could be required to pay substantial damages. In addition, Ansan may be
required to obtain licenses to patents or other proprietary rights of third
parties, in connection with the development and use of its products and
technologies. No assurance can be given that any licenses required under any
such patents or proprietary rights would be made available on terms acceptable
to Ansan, if at all.
 
  Ansan is aware of the existence of prior art references which may affect the
validity of certain claims in the issued patent, which claims broadly cover
AN10, among other compounds. Reexamination or reissue of such patent by the
PTO, in light of these references, may be necessary in order to obtain valid
claims which are both free of the prior art and which specifically cover AN10.
In the course of preparing for reexamination or otherwise, additional prior
art may be uncovered which might affect the validity of such proposed narrow
claims. Such art would need to be brought to the attention of the PTO, in
connection with any reexamination. Moreover, there can be no assurance that
the PTO will grant a request for reexamination, or if granted, that such
reexamination will result in the issuance of the desired claims. In any event,
given that the already-uncovered prior art references relates to compounds but
not to methods of treatment, the existence of such references would not, as a
matter of U.S. patent law, be expected to affect any claims directed to the
use of AN10 to treat beta-hemoglobinopathies as covered in United States
Patent No. 5,569,675 issued in October 1996, which Ansan has licensed from
Bar-Ilan.
 
                                      70

  Ansan is also aware of other patents (the "Perrine patents") which appear to
cover the administration of butyric acid, during gestation or infancy, to
ameliorate beta-hemoglobinopathies disorders, including sickle cell anemia and
beta-thalassemia, by increasing the level of fetal hemoglobin. To the extent
that AN10 converts to butyric acid and in the event Ansan's commercial
activities include administration of AN10 during gestation and/or infancy,
such activities could give rise to issues of infringement of the Perrine
patents.
 
  Ansan also relies on trade secrets and proprietary know-how which it seeks
to protect, in part, by confidentiality agreements with its employees,
consultants, advisors, and others. There can be no assurance that employees of
Ansan, consultants, advisors, or others, will maintain the confidentiality of
such trade secrets or proprietary information, or that the trade secrets or
proprietary information of Ansan will not otherwise become known or be
independently developed by competitors in such a manner that Ansan will have
no practical recourse.
 
SUPPLIERS
 
  Ansan currently obtains from outside suppliers the supplies (i.e., drug
substance) of Pivanex(TM) Injection and Novaheme(TM) Injection necessary to
create the formulations for use in its research and development efforts.
Pursuant to the Apafant License, Boehringer Ingelheim has provided Ansan with
drug substance for currently planned Apafant clinical trials. Nevertheless,
there can be no assurance that such vendors will, in fact, agree to perform
the requested activities for Ansan. There can be no assurance that Ansan will
not experience delays or other supply problems that may materially adversely
affect Ansan's research and development efforts or that Ansan will be able to
obtain an alternate source of supply on a timely basis.
 
MANUFACTURING AND MARKETING
 
  Ansan neither has, nor expects to have in the foreseeable future, the
resources to manufacture or directly market on a commercial scale any products
that it may develop. In connection with its research and development
activities, Ansan may seek to enter into collaborative arrangements with
larger pharmaceutical, health care or chemical companies to assist in funding
the substantial development costs associated with bringing drug products to
market. These entities may also be responsible for commercial scale
manufacturing, which will be subject to applicable FDA regulations (see "--
Government Regulation"). Ansan anticipates that such arrangements may involve
the granting by it of exclusive or semi-exclusive rights to sell specific
products to specified market segments or in particular geographic territories
in exchange for a royalty or other financial considerations.
 
  To date, Ansan has not entered into any commercial manufacturing or
marketing agreements for any of its proposed products. There can be no
assurance that Ansan will be able to enter into any such arrangements on
favorable terms, or at all. Such collaborative marketing arrangements, whether
licenses, joint ventures or otherwise, may result in lower revenues than would
otherwise be generated if Ansan conducted the marketing of its own products.
To the extent that Ansan ultimately determines to undertake commercial scale
manufacturing or direct marketing activities, it will require substantial
additional personnel and financial resources.
 
COMPETITION
 
  The pharmaceutical and biotechnology industries are characterized by rapidly
evolving technology and intense competition. Many companies of all sizes,
including major pharmaceutical companies and specialized biotechnology
companies, are engaged in the development and commercialization of therapeutic
agents designed for the treatment of the same diseases and disorders targeted
by Ansan. Many of the competitors of Ansan have substantially greater
financial and other resources, larger research and development staffs and more
experience in the regulatory approval process.
 
  Ansan is aware that Alpha Therapeutics Corporation ("Alpha") is currently
developing, through technology covered by the Perrine patents, a butyrate-
related treatment for blood disorders that would directly compete with Ansan's
Novaheme(TM) Injection product. Ansan has also become aware of recently
published clinical results
 
                                      71

regarding arginine butyrate, another butyrate-related treatment for blood
disorders that would directly compete with Ansan's Novaheme(TM) Injection
product, which results suggest that when arginine butyrate is given
intravenously for several weeks to a small number of patients, it does not
significantly increase fetal blood hemoglobin levels. There can be no
assurance that Novaheme(TM) Injection will prove to be more efficacious in the
treatment of blood disorders than the drug under development by Alpha or than
arginine butyrate or that, in the event that Novaheme(TM) Injection is
approved for commercialization, that Novaheme(TM) Injection will gain wider
market acceptance than the Alpha product. In addition, Novaheme(TM) Injection
will face competition from hydroxyurea, a therapeutic agent currently marketed
for other indications and which has just completed clinical testing for the
treatment of blood disorders. Although Ansan believes that hydroxyurea will
only have limited effectiveness in the treatment of beta-hemoglobinopathies
since initial studies have shown it to be toxic and, in certain experimental
models, less effective than Novaheme(TM) Injection at increasing the ex vivo
expression of HbF levels, there can be no assurance that Novaheme(TM)
Injection will ultimately prove to be more efficacious at treating blood
disorders than hydroxyurea or that, in the event that Novaheme(TM) Injection
is approved for commercialization, that it will gain wider market acceptance
than hydroxyurea.
 
  Ansan is also aware that BBP is currently developing lexipafant, another
platelet activating factor antagonist, for the treatment of patients with
pancreatitis. BBP is currently engaged in Phase III clinical trials in the
United States and has filed for marketing approval in the EU. If lexipafant is
approved prior to Apafant, it may increase the cost and time required to
obtain approval of Apafant, or limit the indications for which Apafant may be
marketed if it is approved. There can be no assurance that Apafant will prove
more efficacious than lexipafant in treating patients with pancreatitis or, if
approved, that Apafant will gain market acceptance.
 
  In addition, colleges, universities, governmental agencies and other public
and private research organizations are likely to continue to conduct research
and are becoming more active in seeking patent protection and licensing
arrangements to collect royalties for use of technology that they have
developed, some of which may be directly competitive with the technologies
being developed by Ansan. These institutions also compete with Ansan in
recruiting highly qualified scientific personnel. Ansan expects therapeutic
developments in the areas of hematology and acute medical disorders to occur
at a rapid rate and competition to intensify as advances in this field are
made. Accordingly, Ansan will be required to continue to devote substantial
resources and efforts to research and development activities.
 
GOVERNMENT REGULATION
 
  Ansan's research and development activities are, and the production and
marketing of Ansan's products will be, subject to regulation for safety and
efficacy by numerous governmental authorities in the United States and other
countries. In the United States, pharmaceutical products are subject to
rigorous FDA review. The Federal Food, Drug, and Cosmetic Act and other
federal statutes and regulations govern or influence the research testing,
manufacture, safety, labeling, storage, record keeping, approval, advertising
and promotion of such products. Noncompliance with applicable requirements can
result in fines, recall or seizure of products, refusal to permit products to
be imported into or exported out of the United States, refusal of the
government to approve product approval applications or to allow Ansan to enter
into government supply contracts, withdrawal of previously approved
applications and criminal prosecution.
 
  In order to obtain FDA approval of a new drug, Ansan generally must submit
proof of purity, potency, safety and efficacy, among other things. In most
cases, such proof entails extensive clinical and preclinical laboratory tests.
The preclinical and clinical testing, together with preparation of necessary
applications with the FDA, are expensive and may take several years to
complete. There is no assurance that the FDA will act favorably or quickly in
reviewing submitted applications. Significant delays and/or costs may be
encountered by Ansan in its efforts to obtain FDA approvals, which could delay
or preclude Ansan from marketing any products it may develop. The processing
of those applications by the FDA is a lengthy process and may also take
several years. Any future failure to obtain, and/or delay in obtaining, such
approvals could adversely affect the ability of
 
                                      72

Ansan to market its proposed products. Moreover, even if regulatory approval
is granted, such approval may include significant limitations on indicated
uses for which any such products could be marketed. Further, a marketed drug
and its manufacturer are subject to continued review, and later discovery of
previously unknown problems may result in restrictions on such product or
manufacturer, including withdrawal of the product from the market. In
addition, new government regulations may be established that could delay or
prevent regulatory approval of the products under development.
 
  The FDA may also require post-marketing testing and surveillance of approved
products, or place other conditions on its approvals. These requirements could
cause it to be more difficult or expensive to sell the products, and could
therefore restrict the commercial applications of such products. Product
approvals may be withdrawn if compliance with regulatory standards is not
maintained or if problems occur following initial marketing. With respect to
patented products or technologies, delays imposed by the governmental approval
process may materially reduce the period during which Ansan will have the
exclusive right to exploit such technologies.
 
  The Federal Food, Drug, and Cosmetic Act and the regulations promulgated
thereunder govern the testing, manufacture, safety, effectiveness, labeling,
storage, record keeping, approval, advertising and promotion of new drugs. The
procedure for obtaining FDA approval to market a new drug involves several
steps. Initially, the manufacturer must conduct preclinical animal testing to
demonstrate that the product does not pose an unreasonable risk to human
subjects in clinical studies. Upon completion of such animal testing, an IND
must be filed with the FDA before clinical studies may begin. An IND
application consists of, among other things, information about the proposed
clinical trials. Once the IND is approved (or if the FDA fails to act within
30 days), the clinical trials may begin.
 
  Human clinical trials on drugs are typically conducted in three sequential
phases, although the phases may overlap. Phase I trials typically consist of
testing the product in a small number of healthy volunteers or in patients,
primarily for safety in one or more doses. During Phase II, in addition to
safety, the efficacy of the product is evaluated in up to several hundred
patients and sometimes more. Phase III trials typically involve additional
testing for safety and efficacy in an expanded patient population at multiple
test sites. The FDA may order the temporary or permanent discontinuation of a
clinical trial at any time.
 
  The results of the preclinical and clinical testing on new drugs are
submitted to the FDA in the form of an NDA. The NDA approval process requires
substantial time and effort and there can be no assurance that any approval
will be granted on a timely basis, if at all. The FDA may refuse to approve an
NDA if applicable regulatory requirements are not satisfied. Product
approvals, if granted, may be withdrawn if compliance with regulatory
standards is not maintained or problems occur following initial marketing.
 
  There can be no assurance that any required FDA or other governmental
approval will be granted, or if granted, will not be withdrawn. Governmental
regulation may prevent or substantially delay the marketing of Ansan's
proposed products, cause Ansan to undertake costly procedures and furnish a
competitive advantage to more substantially capitalized companies with which
Ansan expects to compete. In addition, the extent of potentially adverse
government regulations which might arise from future administrative action or
legislation cannot be predicted.
 
EMPLOYEES
 
  Ansan currently has six full-time employees. Ansan's future success depends
in significant part upon the continued service of its key scientific personnel
and executive officers and its continuing ability to attract and retain highly
qualified scientific and managerial personnel. Competition for such personnel
is intense and there can be no assurance that Ansan can retain its key
employees or that it can attract, assimilate or retain other highly qualified
technical and managerial personnel in the future.
 
                                      73

                          SUMMARY COMPENSATION TABLE
 
                          SUMMARY COMPENSATION TABLE
                              ANNUAL COMPENSATION
 
  The following sets forth the compensation paid during the last three fiscal
years by Discovery to the person who is expected initially to serve as the
chief executive officer of the Combined Company. No other person who is
expected initially to serve as an executive officer of the Combined Company
received compensation in excess of $100,000 per annum from either Discovery or
Ansan during any of the last three fiscal years.

              NAME AND POSITION               YEAR  SALARY   BONUS  STOCK AWARDS
              -----------------               ---- -------- ------- ------------
                                                        
James S. Kuo, M.D. .......................... 1996 $102,708 $30,000     -- (1)
Chief Executive Officer                       1995      --      --      --
(March 1996 to present)                       1994      --      --      --

- --------
(1) In March 1996, the Company issued 340,000 shares of Common Stock to Dr.
    Kuo. There presently is no trading market for the Common Stock.
 
  The following table sets forth information with respect to the options
exercised by the executive officer named in the Summary Compensation Table
during 1997.
 
                AGGREGATED OPTION EXERCISES IN LAST FISCAL YEAR
                       AND FISCAL YEAR-END OPTION VALUES

                         SHARES OF COMMON      % OF TOTAL
                            UNDERLYING    OPTIONS/SARS GRANTED
                           OPTIONS/SARS     TO EMPLOYEES IN    EXERCISE OR BASE
NAME                         GRANTED          FISCAL YEAR      PRICE ($/SHARE)  EXPIRATION DATE
- ----                     ---------------- -------------------- ---------------- ---------------
                                                                    
James S. Kuo, M.D. .....     200,000             26.74%             $0.20       January 1, 2007

                                      74

                CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS
 
  Pursuant to a private offering held during June through November 1996,
Discovery consummated an offering of Units consisting of Discovery Series A
Preferred Stock and Discovery Common Stock (the "Unit Offering") pursuant to
which Discovery raised aggregate gross proceeds of approximately $22,002,550.
In connection with services rendered by Paramount Capital as placement agent
for the Unit Offering, and pursuant to a Placement Agency Agreement entered
into by Discovery and Paramount Capital, Discovery paid Paramount Capital cash
commissions of approximately $1,980,230, a non-accountable expense allowance
of approximately $880,102 and placement warrants to acquire 220,026 shares of
Discovery Series A Preferred Stock exercisable until November 8, 2006 at an
exercise price of $11 per share and 220,026 shares of Discovery Common Stock,
exercisable until November 8, 2006 at an exercise price of $0.25 per share.
 
  Pursuant to such placement agency agreement, on November 7, 1996, Discovery
and Paramount Capital entered into a financial advisory agreement (the
"Financial Advisory Agreement"), pursuant to which Paramount Capital will
receive a monthly retainer of $4,000 per month for a minimum of 24 months,
plus expenses and success fees.
 
  Discovery has agreed to indemnify Paramount Capital and certain related
parties with respect to liabilities arising out of the Unit Offering under the
Federal securities laws pursuant to the Placement Agency Agreement entered
into by Discovery and Paramount Capital. Discovery has also agreed to
indemnify Paramount Capital and certain related parties with respect to
liabilities arising out of services rendered pursuant to the Financial
Advisory Agreement.
 
  Lindsay A. Rosenwald, M.D., who is the Chief Executive Officer of RAQ, LLC,
a principal stockholder of Discovery, is also the Chairman of the Board of
Directors, Chief Executive Officer, President and the sole stockholder of
Paramount Capital. Dr. Rosenwald is also a director of Titan and a director of
Ansan. Steven H. Kanzer, C.P.A., Esq., the Chairman of the Board of Directors
and a stockholder of Discovery, is a Senior Managing Director of Paramount
Capital and Senior Managing Director--Head of Venture Capital of Paramount
Investments. Kenneth Johnson, the Director of Business Development and a
stockholder of Discovery, is a Technology Associate of an affiliate of
Paramount Capital. Steven Birnbaum, Discovery's Project Manager for the ST-630
program for postmenopausal osteoporosis, was previously employed by Paramount
Investments as a Technology Associate.
 
  Paramount Capital acted as placement agent in connection with Titan's
private equity placement during 1993 and in connection there with received
fees of              .
 
  Louis R. Bucalo, Chairman of Ansan's Board of Directors, is also President,
Chief Executive Officer and a member of the Board of Directors of Titan, the
majority stockholder of Ansan.
 
  In 1992, Titan purchased 327,446 shares of Common Stock of Ansan for nominal
consideration. In May 1994, Titan purchased 532,651 shares of Ansan preferred
stock for $992,592 in cash and the forgiveness of a debt in the amount of
$1,449,064, which shares were converted into 532,651 shares of Common Stock
upon completion of Ansan's IPO during August and September of 1995. In
connection with Titan's purchase of such preferred stock of Ansan, Titan was
granted the right, exercisable in prescribed circumstances, to demand or to
participate in certain registrations of securities under the Securities Act.
Stock held by Titan will be repurchased by Ansan pursuant to the Titan
Sublicense Agreement.
 
  From its inception in November 1992 until May 1995, Ansan received loans
from Titan to enable it to fund its operations. At March 31, 1995, the
aggregate amount of such loans outstanding was $1,551,252. Upon the closing of
Ansan's IPO, the March 31, 1995 balance was converted into shares of Ansan
Common Stock at the conversion rate of $4.40 per share. From April 1995
through May 1995, Titan made additional non-interest bearing working capital
advances to Ansan in the aggregate amount of $108,280, which amount were
repaid with cash.
 
                                      75

  Since Ansan's inception, Titan has provided certain executive,
administrative, financial, business development and regulatory services to
Ansan. Ansan pays Titan for such services on a quarterly basis. Ansan also
pays for any out-of-pocket expenses incurred by Titan in providing the
services to Ansan. During the period from inception through December 31, 1993,
the year ended December 31, 1994, the year ended December 31, 1995, and the
year ended December 31, 1996, Ansan incurred expenses in the aggregate of
approximately $205,000, $523,000, $376,000 and $57,000 respectively, pursuant
to the services arrangement. Ansan has in the past used certain facilities and
equipment leased by Titan and reimbursed Titan for the expenses incurred by
Titan with respect to such use, in addition to having entered an assignment
and sublease with Titan, along with the other subsidiaries of Titan, under
such equipment lease. Ansan's liability with respect to such equipment lease
has been terminated.
 
  In May 1993, Discovery issued a total of 1,132,500 shares of Common Stock to
Lindsay A. Rosenwald, M.D., for $0.002 per share. Dr. Rosenwald subsequently
transferred these shares to RAQ, LLC. In March 1996, Discovery issued an
additional 1,595,100 shares of Common Stock to RAQ, LLC for $0.002 per share.
Dr. Rosenwald is the Chief Executive Officer of RAQ, LLC. During 1995 and the
first quarter of 1996, Dr. Rosenwald provided loans to Discovery in the
aggregate amount of $17,794, the proceeds of which were used for salary and
administration purposes. Dr. Rosenwald contributed such loans to the capital
of Discovery prior to the initiation of the Unit Offering. Dr. Rosenwald had
guaranteed a credit facility provided by Fleet Bank in favor of Discovery in
an amount up to $350,000. The proceeds of these loans were used by Discovery
in connection with its entry into the CMHA License Agreement and for general
operating and working capital purposes. The outstanding balance of such loans,
$201,000, was repaid in September 1996 using a portion of the proceeds of the
Unit Offering.
 
  In May 1994, nine members of Titan's Board of Directors, including Dr.
Rosenwald, each received options under Ansan's 1993 Stock Option Plan to
purchase 335 shares of Common Stock at an exercise price of $.29 per share.
 
  In July 1994, Dr. Bucalo, received options to purchase 15,052 shares of
Ansan Common Stock at an exercise price of $.29 per share.
 
  In February 1995, Discovery issued a total of 194,250 shares of Common Stock
for $0.002 per share to Mr. Kanzer and an additional 85,000 shares for $0.002
per share to certain family member of Mr. Kanzer. In March 1996, Discovery
issued an additional 242,500 shares of Common Stock to Mr. Kanzer for $0.002
per share. In February 1995, Discovery issued an additional 1,500 shares of
Common Stock and in March 1996 issued an additional 123,500 shares of Common
Stock to Evan Myrianthopoulos, the Chief Operating Officer, Secretary and a
Director of Discovery, for $0.002 per share. In September 1996, Discovery
issued an additional 62,000 shares of Common Stock to Mr. Myrianthopoulos for
$0.002 per share in recognition of his identification and introduction of the
KL4-Surfactant technology to Discovery, which preceded his employment by
Discovery. In May 1996, Discovery entered into employment agreements with
Messrs. Kanzer and Myrianthopoulos. Mr. Myrianthopoulos' employment agreement
was terminated when he became a full-time employee of Discovery effective
January 1, 1997.
 
  In April 1996, Discovery entered into a three-year employment agreement with
James S. Kuo, the Chief Executive Officer and President and a Director of the
Company. In October 1996, ATI entered into a four-year employment agreement
with Robert J. Capetola, Ph.D., the President, Chief Executive Officer and
Chairman of the Board of Acute Therapeutics, Inc. ("ATI").
 
  In connection with Dr. Max Link's serving on the Board of Directors of
Discovery, Discovery issued him, in September 1996, 25,000 options exercisable
at $0.20 per share. Discovery has issued 50,000 shares of Common Stock for
$0.002 per share to Steve Birnbaum.
 
  In October 1996, Harris Kanzer, who is the father of Steve H. Kanzer,
purchased 6,000 shares of Common Stock and 6,000 shares of Series A Preferred
Stock from Discovery in the Unit Offering.
 
                                      76

  In February 1997, Discovery granted options exercisable at $0.20 per share
for the purchase of 200,000 shares of the Common Stock to Dr. Kuo, for the
purchase of 40,000 shares of the Common Stock to Mr. Kanzer; and for the
purchase of 30,000 shares of the Common Stock to Mr. Myrianthopoulos. Twenty-
five percent of the foregoing options vested immediately and the remainder of
such options are subject to vesting on a monthly basis over a 36-month period
that commenced January 31, 1997.
 
  Pursuant to the terms of the Merger Agreement, the Discovery options
described above will be assumed by Ansan (except as adjustments may occur
pursuant to the Exchange Ratio) and shall become exercisable for a number of
shares of Ansan Common Stock equal to the number of shares of Discovery Common
Stock for which they were previously exercisable multiplied by the Common
Exchange Ratio.
 
  To the best knowledge of Ansan and Discovery, no individual will become
eligible for a "change of control" payment as a result of the transactions
contemplated by the Merger Agreement.
 
  In March 1997, Titan and Ansan entered into an agreement for financing
pursuant to which Titan advanced Ansan $1,000,000 in return for the Debenture.
The Debenture will be repaid upon closing of the Merger. See "Information
Concerning Ansan--Relationship with Titan Pharmaceuticals, Inc."
 
  Each of Discovery and Ansan has agreed pursuant to its charter documents to
indemnify its Directors to the maximum extent permissible under the DGCL.
 
  Each of Discovery and Ansan believes that all of the transactions set forth
above with respect to it were made on terms no less favorable to it than could
have been obtained from unaffiliated third parties. Ansan has adopted a policy
that all future transactions, including loans, between Ansan and its officers,
directors, principal stockholders and their affiliates will be approved by a
majority of the Board of Directors, including a majority of the independent
and disinterested outside directors on the Board of Directors, and will
continue to be on terms no less favorable to Ansan than could be obtained from
unaffiliated third parties. It is expected that the Combined Company will
continue this policy.
 
                                      77

                            PRINCIPAL STOCKHOLDERS
 
  The following sets forth certain information regarding beneficial ownership
of the Ansan Common Stock and the Discovery Common Stock as of July 31, 1997,
and the beneficial ownership such shares will represent after the Merger (i)
by each person known by Ansan to beneficially own more than five percent of
the Ansan Common Stock, (ii) by each person known by Discovery to beneficially
own more than five percent of the Discovery Common Stock, (iii) by each
director of Ansan and each director of Discovery, (iv) by the chief executive
officer and the four most highly paid executive officers of each of Ansan and
Discovery, (v) by all directors and all such executive officers of Ansan as a
group, and (vi) by all directors and all such executive officers of Discovery
as a group.

                                  ANSAN SHARES    DISCOVERY SHARES
                                  BENEFICIALLY      BENEFICIALLY     BENEFICIAL
                                 OWNED PRIOR TO    OWNED PRIOR TO    OWNERSHIP
                                    MERGER(1)         MERGER(1)     AFTER MERGER
                                ----------------- ----------------- ------------
NAME AND ADDRESS                 NUMBER   PERCENT  NUMBER   PERCENT   PERCENT
- ----------------                --------- ------- --------- ------- ------------
                                                     
RAQ, LLC(2)...................                    2,574,125  38.15%    31.58%
787 Seventh Avenue, 44th Floor
New York, NY 10019
Lindsay A. Rosenwald,
 M.D.(2)(10)..................  1,212,989  32.08% 2,574,125  38.15%    31.58%
787 Seventh Avenue, 44th Floor
New York, NY 10019
Paramount Capital
 Incorporated(3)..............                    1,100,130  14.02%    11.89%
787 Seventh Avenue, 48th Floor
New York, NY 10019
Steven H. Kanzer, C.P.A.,
 Esq.(4)......................                      455,917   6.74%     5.58%
787 Seventh Avenue, 44th Floor
New York, NY 10019
James S. Kuo, M.D.(5).........                      435,833   6.37%     5.28%
787 Seventh Avenue, 44th Floor
New York, NY 10019
Evan Myrianthopoulos(6).......                      196,475   2.91%     2.41%
787 Seventh Avenue, 44th Floor
New York, NY 10019
David Crockford(7)............                       47,917      *         *
787 Seventh Avenue, 44th Floor
New York, NY 10019
Juerg F. Geigy, Esq. .........                       35,000      *         *
44 Elisabethenstrasse
CH-4051 Basel, Switzerland
Max Link, Ph.D.(8)............                       35,000      *         *
230 Central Park West, Apt.
 14A
New York, NY 10024
Herbert H. McDade, Jr.(9).....                       35,000      *         *
Access Pharmaceuticals
660 White Plains Road, Suite
 400
Tarrytown, NY 10501
Marc C. Rogers, M.D.(9).......                       47,500      *         *
4406 W. Cornwallis Road
Durham, NC 27705

                                      78

                                  ANSAN SHARES     DISCOVERY SHARES
                                  BENEFICIALLY       BENEFICIALLY     BENEFICIAL
                                 OWNED PRIOR TO     OWNED PRIOR TO    OWNERSHIP
                                    MERGER(1)          MERGER(1)     AFTER MERGER
                                -----------------  ----------------- ------------
NAME AND ADDRESS                 NUMBER   PERCENT   NUMBER   PERCENT   PERCENT
- ----------------                --------- -------  --------- ------- ------------
                                                      
Discovery Directors and Four
Discovery Officers as a Group
(7 persons)...................                     1,263,225  18.06%    15.33%
Titan Pharmaceuticals,
 Inc.(10).....................  1,212,654  32.08%                           *
400 Oyster Point Blvd., #545
South San Francisco, CA 94080
Louis R. Bucalo, M.D.(10).....  1,227,706  32.35%                           *
c/o Ansan, Inc.
400 Oyster Point Blvd., #545
South San Francisco, CA 94080
Vaughan H. J. Shalson(11).....    182,000  4.59%                            *
c/o Ansan, Inc.
400 Oyster Point Blvd., #545
South San Francisco, CA 94080
Richard Sperber(11)...........     27,823                                   *
c/o Ansan, Inc.
400 Oyster Point Blvd., #545
South San Francisco, CA 94080
Ilan Cohn, Ph.D.(11)..........     22,800                                   *
c/o Ansan, Inc.
400 Oyster Point Blvd., #545
South San Francisco, CA 94080
David Naveh, Ph.D.(11)........     22,800                                   *
c/o Ansan, Inc.
400 Oyster Point Blvd., #545
South San Francisco, CA 94080
All executive officers and ...  1,483,464 36.62%                            *
directors of Ansan as a group
(5 persons)
Discovery Laboratories,
 Inc.(12).....................    928,571 24.56%                            *
509 Madison Avenue, 14th Floor
New York, NY 10022

- --------
 (1) Determined in accordance with Rule 13d-3 under the Exchange Act. Shares
     issuable upon exercise of outstanding options that are exercisable within
     60 days from the date of this Prospectus/Proxy Statement are considered
     outstanding for purposes of calculating the percentage ownership of Ansan
     Common Stock or Discovery Common Stock, as the case may be, of the person
     holding such options but are not considered outstanding for computing the
     percentage ownership of any other person.
 
 (2) Dr. Rosenwald is the Chief Executive Officer of RAQ, LLC and therefore
     may be deemed to be the beneficial owner of such shares by virtue of his
     right to vote and/or dispose of shares held by RAQ, LLC. Dr. Rosenwald is
     the Chairman, Chief Executive Officer and sole stockholder of Paramount
     Capital. Dr. Rosenwald disclaims beneficial ownership of any securities
     issuable upon exercise of warrants granted to employees of Paramount
     Capital.
 
 (3) Represents warrants exercisable at $0.25 per share for the purchase of
     220,026 shares of Discovery Common Stock and warrants exercisable at $11
     per share for the purchase of 220,026 shares of Discovery Series A
     Preferred Stock, all of which are exercisable within 60 days of the date
     hereof.
 
                                      79

 (4) Includes options exercisable at $0.20 per share to purchase 19,167 shares
     of Discovery Common Stock, all of which are exercisable within 60 days of
     the date hereof. Does not include an additional 91,000 shares of
     Discovery Common Stock owned by certain family members of Mr. Kanzer as
     to which Mr. Kanzer disclaims beneficial ownership.
 (5) Includes 255,000 shares that are subject to Discovery's right to
     repurchase in the event Dr. Kuo's employment with Discovery is terminated
     prior to March 1999 and may not be sold or transferred prior to the lapse
     of Discovery's right to repurchase. Also includes options exercisable at
     $0.20 per share to purchase 95,833 shares of Discovery Common Stock, all
     of which are exercisable within 60 days of the date hereof.
 
 (6) Includes options exercisable at $0.20 per share to purchase 14,375 shares
     of Discovery Common Stock, all of which are exercisable within 60 days
     thereof. Does not include an additional 4,900 shares of Discovery Common
     Stock owned by Mr. Myrianthopoulos' brother, as to which Mr.
     Myrianthopoulos disclaims beneficial ownership.
 
 (7) Represents options exercisable at $0.20 per share to purchase 47,917
     shares of Discovery Common Stock, all of which are exercisable within 60
     days of the date hereof.
 
 (8) Includes options exercisable at $0.20 per share to purchase 10,000 shares
     of Discovery Common Stock, all of which are exercisable within 60 days of
     the date hereof.
 
 (9) Represents or includes options exercisable at $0.10 per share to purchase
     25,000 shares of Discovery Common Stock and options exercisable at $0.20
     per share to purchase 10,000 shares of Discovery Common Stock, all of
     which are exercisable within 60 days of the date hereof.
 
(10) Includes 1,212,654 shares owned of record by Titan which stock will be
     cancelled as of the Effective Time. Dr. Bucalo is president and Chief
     Executive Officer and a member of Titan's Board of Directors and
     Dr. Rosenwald is a member of Titan's Board of Directors. As a result,
     each of Drs. Rosenwald and Bucalo may be deemed to share voting or
     investment power with respect to such shares. Each of these individuals,
     however, disclaims beneficial ownership with respect to such shares. Dr.
     Rosenwald beneficially owns 335 shares of Ansan Common Stock issuable
     upon exercise of outstanding options.
 
(11) Represents shares issuable on the exercise of outstanding options.
 
(12) Represents the Ansan Series A Preferred Stock purchased pursuant to the
     Series A Purchase Agreement which stock will be cancelled as of the
     Effective Time.
- --------
  * Less than one percent (1%)
 
                                      80

          ADDITIONAL MATTERS FOR CONSIDERATION BY ANSAN STOCKHOLDERS
 
  In addition to the consideration of the Merger Proposal, the stockholders of
Ansan will be asked to consider and vote upon the following matters at the
Ansan Special Meeting.
 
PROPOSAL 2--REVERSE STOCK SPLIT--APPROVAL OF AMENDMENT TO ANSAN CERTIFICATE OF
                                 INCORPORATION
 
GENERAL
 
  The Ansan Board of Directors has approved an amendment to Article FOURTH of
Ansan's Certificate of Incorporation to convert and reconstitute the Ansan
Common Stock whereby a number of shares of Ansan Common Stock between two and
five, such number consisting only of whole shares and tenths of shares, as
shall be determined by the Board of Directors shall be converted and
reconstituted into one share of new Ansan Common Stock ("New Common Stock")
and to pay cash equal to the fair market value, as determined by the Board of
Directors, of any fractional share resulting from such conversion and
reconstitution (the "Reverse Stock Split"). The Ansan Certificate Amendment
filed with the Delaware Secretary of State will reflect the reverse stock
split and ratio selected by the Ansan Board of Directors. The Board of
Directors will determine the fair market value payment to holders of
fractional shares of Ansan Common Stock based upon the fair market value of
the Ansan Common Stock.
 
  Ansan is currently authorized to issue 20,000,000 shares of Ansan Common
Stock. The number of authorized shares of Ansan Common Stock would not be
changed by the proposed amendment and, consequently, Ansan would be able to
issue a substantial number of additional shares of Ansan Common Stock without
further stockholder approval. Although the Board of Directors does not have
any present plans to issue additional shares of Ansan Common Stock other than
pursuant to the Merger, it believes that it is desirable for Ansan to have
additional authorized but unissued Ansan Common Stock to provide flexibility
to act promptly with respect to acquisitions, public and private financings
and for other appropriate purposes. Such availability will eliminate the
delays and expense which otherwise might be incurred if stockholder approval
were required for certain transactions involving the issuance of securities.
Furthermore, in the event of a proposed merger, tender offer or other attempt
to gain control of Ansan of which the Board of Directors did not approve, it
would be possible for the Board of Directors to authorize the issuance of a
substantial block of Ansan Common Stock, without obtaining stockholder
approval, as part of an alternative business combination or a recapitalization
which stockholders might find more attractive. However, additional authorized
Ansan Common Stock could also be issued to one or more persons who might
thereby obtain sufficient voting power to ensure that any proposal to remove
directors, to accomplish certain business combinations opposed by the Board of
Directors, or to alter, amend or repeal any provisions of Ansan's Certificate
of Incorporation or By-laws, would be defeated. An effect of the increased
number of authorized shares resulting from the Reverse Stock Split, therefore,
may be to deter a future takeover attempt which holders of Ansan Common Stock
may deem to be in their best interests or in which holders of Ansan Common
Stock may receive a premium for their shares over the market price. However,
the Board of Directors believes that the benefits of providing it with the
flexibility to issue shares without delay for any business purpose, including
as an alternative to an unsolicited takeover attempt opposed by the Board,
outweigh the possible disadvantages of dilution and discouraging such
unsolicited takeover proposals and that it is prudent and in the best
interests of the stockholders to provide the advantage of greater flexibility
which will result from the approval of the proposed Reverse Stock Split.
 
  If approved by the Ansan stockholders, the Reverse Stock Split would become
effective upon the filing of the Ansan Certificate Amendment with the Delaware
Secretary of State on any date selected by the Board of Directors on or prior
to January 31, 1998 (the "Amendment Effective Date"). If no Reverse Stock
Split is effected by the Amendment Effective Date, the Board will take action
to abandon the Reverse Stock Split pursuant to Section 242(c) of the DGCL.
 
                                      81

  By approving the Ansan Certificate Amendment, the stockholders authorize the
Ansan Board of Directors to implement the Reverse Stock Split at any time
between the approval of the Ansan Certificate Amendment and January 31, 1998.
The stockholders, accordingly, may not, following approval of the Ansan
Certificate Amendment, rescind their vote even if the timing of the Ansan
Certificate Amendment may adversely affect any stockholder.
 
  Ansan's stockholders will recognize no taxable gain or loss as a result of
the Reverse Stock Split. The basis of the shares of Ansan Common Stock to be
issued after the Reverse Stock Split will be the same as the basis prior to
the Reverse Stock Split.
 
  Consummation of the Reverse Stock Split will, in and of itself, not result
in a change in the relative equity position or voting power of the holders of
Ansan Common Stock although such will be significantly impacted by the Merger
Proposal. As a result, however, of the fact that the Reverse Stock Split will
reduce the number of issued and outstanding shares of Ansan Common Stock
without changing the par value of such stock, the Reverse Stock Split will
result in a decrease in Ansan's stated capital.
 
  The Board of Directors believes that it is difficult to attract new
investors to Ansan due to the fact that the Ansan Common Stock trades at a
relatively low price (generally less than $2.00 per share). Institutional
investors are typically restricted from investing in companies whose stocks
trade at relatively low prices per share. Stockbrokers also are sometimes
subject to internal restrictions on their ability to recommend lower priced
stocks because of the general presumption that such stocks may be highly
speculative. Furthermore, stock which trades in the trading range of Ansan
Common Stock may not be marginable. The Board of Directors believes that the
Reverse Stock Split may have the effect of increasing the market price per
share of Ansan Common Stock. An increase in the per share price of Ansan
Common Stock may, over time, alleviate some or all of these conditions,
although such alleviation cannot be assured. On the other hand, stockholders
should be aware that a reverse stock split may result in a decrease in the
trading volume of Ansan Common Stock due to the decrease in the number of
outstanding shares.
 
PURPOSES OF THE REVERSE SPLIT AMENDMENT
 
  The Reverse Stock Split would decrease the number of shares of Ansan Common
Stock outstanding and presumably increase the per share market price for the
New Common Stock. The principal reasons for the Reverse Stock Split are to
stimulate interest in the Ansan Common Stock, promote greater liquidity for
Ansan's stockholders and to put Ansan in a position to have the Ansan Common
Stock continue to be listed on the Nasdaq SmallCap Market.
 
  There can be no assurance that any of the intended effects of the Reverse
Stock Split will occur, that the price per share of Ansan Common Stock will
increase proportionately with the decrease in the number of shares, or that
any price increase can be sustained for a prolonged period of time. There also
can be no assurance that Ansan will be able to continue to meet the
maintenance listing requirements of the Nasdaq SmallCap Market or that the
Combined Company will be able to meet the new listing or maintenance listing
requirements that will be applicable to it.
 
                                      82

EFFECT OF THE REVERSE STOCK SPLIT
 
  The following table shows the effect of the Reverse Stock Split, as of the
Effective Time, at the minimum split ratio (one-for-two) and at the maximum
split ratio (one-for-five) (this table is not exhaustive of all possible
Reverse Stock Splits that fall within the Board-approved range and is only
intended for illustrative purposes):

                                                             NEW COMMON STOCK
                                                          ----------------------
                                                                       ONE-FOR-
                                               EFFECTIVE  ONE-FOR-TWO FIVE SPLIT
                                                  TIME    SPLIT RATIO   RATIO
                                               ---------- ----------- ----------
                                                             
   Common Stock Outstanding..................   9,516,524   4,758,262  1,903,305
   Shares of Common Stock issuable upon con-
    version of Series B Preferred Stock......  10,274,940   5,137,470  2,054,988
   Shares of Common Stock issuable upon exer-
    cise of outstanding options and warrants.   2,412,029   1,206,014    482,406
   Total.....................................  22,203,493  11,101,746  4,440,699
   Decrease in Stated Capital................         --  $    11,102 $   17,763

  The affirmative vote of a majority of the stock entitled to vote is required
to approve the Ansan Certificate Amendment. Properly executed, unrevoked
proxies will be voted FOR Proposal 2 unless a vote against Proposal 2 or
abstention is specifically indicated in the proxy.
 
  THE BOARD OF DIRECTORS RECOMMENDS THAT THE STOCKHOLDERS APPROVE THE ANSAN
CERTIFICATE AMENDMENT.
 
                                      83

         PROPOSAL 3--APPROVAL OF AMENDMENT OF ANSAN STOCK OPTION PLAN
 
  The Board of Directors has approved, subject to stockholder approval,
amendments to Ansan's 1995 Stock Option Plan (the "Ansan Stock Option Plan")
increasing the number of shares reserved for issuance thereunder. The
stockholders are asked to approve the adoption of these amendments to the
Ansan Stock Option Plan.
 
THE EXISTING PLAN
 
  The purpose of the Ansan Stock Option Plan is to secure for Ansan and its
stockholders the benefits arising from capital stock ownership by employees,
officers and directors of, and consultants or advisors to, Ansan who are
expected to contribute to Ansan's future growth. Ansan can grant either
incentive stock options ("ISOs") or nonqualified stock options ("NQOs") under
the Ansan Stock Option Plan. Only full-time employees of Ansan, currently
approximately six people, are eligible to receive ISOs or NQOs. Consultants
and advisors are eligible to receive only NQOs.
 
  The Plan provides for the automatic grant of an option ("Director Option")
to purchase 5,000 shares of Ansan Common Stock to each director who is not an
employee or principal stockholder of Ansan ("Eligible Director") upon his/her
initial election or appointment to the Board of Directors. Thereafter, each
Eligible Director is granted a Director Option to purchase 1,000 shares of
Ansan Common Stock on the day immediately following the date of each annual
meeting of Ansan's stockholders. The exercise price of Director Options is the
fair market value of Ansan's Common Stock on the date of grant. Director
Options are exercisable in four equal annual installments commencing six
months from the date of grant.
 
  Options granted expire 10 years after the date of grant, or earlier, in the
event of termination of the optionee's employment or consulting relationship
with Ansan. Director Options expire on the earlier of 10 years after the date
of grant or 90 days after the termination of the director's service on the
Board of Directors. The per share exercise price of ISOs may not be less than
100% of the fair market value of the Common Stock on the date of grant.
 
  The consideration payable upon exercise of, or for tax payable in connection
with the exercise of, an option may be paid in cash, or by delivery of Ansan
Common Stock or other consideration approved by the Board of Directors. Ansan
will not receive any consideration upon the grant of any options. Options may
be exercised immediately, or may vest in accordance with a schedule related to
the particular grant, and must generally be exercised within three months
after a participant's employment by, or consulting or advisory relationship
with, Ansan terminates. If termination is due to the participant's death,
retirement or disability, the options may be exercised for twelve months
thereafter. In the event of certain transactions, including for example, sale
of all or substantially all the assets of Ansan, a consolidation or merger in
which Ansan is not the surviving company, or a liquidation of Ansan, the Board
of Directors is authorized to take a number of actions related to outstanding
options, including acceleration of vesting.
 
  The Board may amend or modify the Ansan Stock Option Plan or any option at
any time, except that the consent of a participant is required if the
participant's rights under an outstanding option would be impaired. In
addition, to the extent required for the Ansan Stock Option Plan to satisfy
the conditions of Rule 16b-3 under the Exchange Act, or, with respect to
provisions solely as they relate to ISOs, to the extent required for the Ansan
Stock Option Plan to comply with Section 422 of the Code, the stockholders of
Ansan must approve any amendment or modification of the Ansan Stock Option
Plan that would (i) increase the total number of shares reserved under the
Ansan Stock Option Plan, (ii) change the minimum price terms for option
exercise, (iii) change the class of persons eligible to participate in the
Ansan Stock Option Plan, (iv) extend the maximum option exercise period or (v)
materially increase the benefits accruing to participants under the Ansan
Stock Option Plan.
 
                                      84

FEDERAL INCOME TAX CONSEQUENCES
 
  THE FOLLOWING SUMMARY OF FEDERAL INCOME TAX CONSEQUENCES IS BASED UPON
EXISTING STATUTES, REGULATIONS AND INTERPRETATIONS THEREOF. THE APPLICABLE
RULES ARE COMPLEX, AND INCOME TAX CONSEQUENCES MAY VARY DEPENDING UPON THE
PARTICULAR CIRCUMSTANCES OF EACH ANSAN STOCK OPTION PLAN PARTICIPANT. THIS
PROXY STATEMENT DESCRIBES FEDERAL INCOME TAX CONSEQUENCES OF GENERAL
APPLICABILITY BUT DOES NOT PURPORT TO DESCRIBE PARTICULAR CONSEQUENCES TO EACH
INDIVIDUAL ANSAN STOCK OPTION PLAN PARTICIPANT OR FOREIGN, STATE OR LOCAL
INCOME TAX CONSEQUENCES, WHICH MAY DIFFER FROM UNITED STATES FEDERAL INCOME
TAX CONSEQUENCES.
 
INCENTIVE STOCK OPTIONS
 
  Award; Exercise. ISOs are intended to constitute "incentive stock options"
within the meaning of Section 422 of the Code. ISOs may be granted only to
employees of Ansan (including directors who are also employees). An optionee
does not recognize taxable income upon either the grant or exercise of an ISO.
However, the excess of the fair market value of the shares purchased upon
exercise over the option exercise price (the "Option Spread") is includable in
the optionee's "alternative minimum taxable income" ("AMTI") for purposes of
the alternative minimum tax ("AMT"). The Option Spread is generally measured
on the date of exercise and is includable in AMTI in the year of exercise.
Special rules regarding the time of AMTI inclusion may apply for shares
subject to a repurchase right or other "substantial risk of forfeiture"
(including, in the case of each person subject to the reporting requirements
of Section 16 of the Exchange Act, limitations on resale of shares imposed
under Section 16(b) of the Exchange Act).
 
  Sale of Option Shares. If an optionee holds the shares purchased under an
ISO for at least two years from the date the ISO was granted and for at least
one year from the date the ISO was exercised, any gain from a sale of the
shares other than to Ansan is taxable as long-term capital gain. Under these
circumstances, Ansan would not be entitled to a tax deduction at the time the
ISO is exercised or at the time the stock is sold. If an optionee were to
dispose of stock acquired pursuant to an ISO before the end of the required
holding periods (a "Disqualifying Disposition"), the amount by which the
market value of the stock at the time the ISO is exercised exceeds the
exercise price (or, if less, the amount of gain realized on the sale) is
taxable as ordinary income, and Ansan is entitled to a corresponding tax
deduction. Such income is subject to information reporting requirements and
may become subject to income and employment tax withholding. Gain from a
Disqualifying Disposition in excess of the amount required to be recognized as
ordinary income is capital gain, which is generally taxed at lower rates than
ordinary income. Optionees are required to notify Ansan immediately prior to
making a Disqualifying Disposition. If stock is sold to Ansan rather than to a
third party, the sale may not produce capital gain or loss. A sale of shares
to Ansan will constitute a redemption of such shares which could be taxable as
a dividend unless the redemption is "not essentially equivalent to a dividend"
within the meaning of the Code. The timing and amount of income from a
Disqualifying Disposition and the beginning of the optionee's holding period
for determining whether capital gain or loss is long- or short-term may be
affected if option stock is acquired subject to a repurchase right or other
"substantial risk of forfeiture" (including in the case of each person subject
to the reporting requirements of Section 16 of the Exchange Act, limitations
on resale of shares imposed under Section 16(b) of the Exchange Act).
 
  Exercise With Stock. If an optionee pays for ISO shares with shares of Ansan
acquired under an ISO or a qualified employee stock purchase plan ("statutory
option stock"), the tender of shares is a Disqualifying Disposition of the
statutory option stock if the above described (or other applicable) holding
periods respecting those shares have not been satisfied. If the holding
periods with respect to the statutory option stock are satisfied, or the
shares were not acquired under a statutory stock option of Ansan, then any
appreciation in value of the surrendered shares is not taxable upon surrender.
Special basis and holding period rules apply where previously owned non-
statutory option stock is used to exercise an ISO.
 
                                      85

NONQUALIFIED STOCK OPTIONS
 
  Award; Exercise. An optionee is not taxable upon the award of a NQO. Federal
income tax consequences upon exercise will depend upon whether the shares
thereby acquired are subject to a "substantial risk of forfeiture." If the
shares are not subject to a substantial risk of forfeiture, or if they are so
restricted and the optionee files an election under Section 83(b) of the Code
(a "Section 83(b) Election") with respect to the shares, the optionee will
have ordinary income at the time of exercise measured by the Option Spread on
the exercise date. The optionee's tax basis in the shares will be the fair
market value of the shares on the date of exercise, and the holding period for
purposes of determining whether capital gain or loss upon sale is long- or
short-term also will begin on or immediately after that date. If the shares
are subject to a substantial risk of forfeiture and no Section 83(b) Election
is filed, the optionee will not be taxable upon exercise, but instead will
have ordinary income on the date the restrictions lapse, in an amount equal to
the difference between the amount paid for the shares under the NQO and their
fair market value as of the date of lapse; in addition, the optionee's holding
period will begin on the date of the lapse.
 
  Whether or not the shares are subject to a substantial risk of forfeiture,
the amount of ordinary income taxable to an optionee who is an employee at the
time of grant constitutes "supplemental wages" subject to withholding of
income and employment taxes by Ansan, and Ansan receives a corresponding
income tax deduction.
 
  Sale of Option Shares. Upon sale, other than to Ansan, of shares acquired
under a NQO, an optionee generally will recognize capital gain or loss to the
extent of the difference between the sale price and the optionee's tax basis
in the shares, which will be long-term gain or loss if the employee's holding
period in the shares is more than one year. If stock is sold to Ansan, rather
than to a third party, the sale may not produce capital gain or loss. A sale
of shares to Ansan will constitute a redemption of such shares, which could be
taxable as a dividend unless the redemption is "not essentially equivalent to
a dividend" within the meaning of the Code.
 
  Exercise with Stock. If an optionee tenders Common Stock to pay all or part
of the exercise price of a NQO, the optionee will not have a taxable gain or
deductible loss on the surrendered shares. Instead, shares acquired upon
exercise that are equal in value to the fair market value of the shares
surrendered in payment are treated as if they had been substituted for the
surrendered shares, taking as their basis and holding period the basis and
holding period that the optionee had in the surrendered shares. The additional
shares are treated as newly acquired with a zero basis.
 
  If the surrendered shares are statutory option stock as described above
under "Incentive Stock Options" with respect to which the applicable holding
period requirements for favorable income tax treatment have not expired, then
the newly acquired shares substituted for the statutory option shares should
remain subject to the federal income tax rules governing the surrendered
shares, but the surrender should not constitute a Disqualifying Disposition of
the surrendered stock.
 
SPECIAL FEDERAL INCOME TAX CONSIDERATION DUE TO SHORT SWING PROFIT RULE
 
  The potential liability of a person subject to Section 16 of the Exchange
Act to repay short-swing profits from the resale of shares acquired under an
Ansan plan constitutes a "substantial risk of forfeiture" within the meaning
of the above-described rules, which is generally treated as lapsing at such
time as the potential liability under Section 16 lapses. Persons subject to
Section 16 who would be required by Section 16 to repay profits from the
immediate resale of stock acquired under an Ansan plan should consider whether
to file a Section 83(b) Election at the time they acquire stock under an Ansan
plan in order to avoid deferral of the date that they are deemed to acquire
shares for Federal income tax purposes.
 
THE PROPOSED AMENDMENT
 
  Currently, the Ansan Stock Option Plan provides that a total of 150,000
shares of Ansan Common Stock may be issued thereunder. On May 8, 1997, the
Ansan Board of Directors approved an increase in the number of
 
                                      86

shares that may be issued under the Ansan Stock Option Plan to 375,000 shares
of Ansan Common Stock, subject to stockholder approval. The proposed amendment
to the Ansan Stock Option Plan increases the number of shares of Ansan Common
Stock available for issuance thereunder to a total of 1,187,400 shares of
Ansan Common Stock, in order to ensure that there will be a sufficient reserve
of shares following the Effective Time to permit the granting of further
options under such plan. In the event the Reverse Stock Split is effected, the
Board of Directors will not grant options pursuant to the Ansan Stock Option
Plan that would result in more than the maximum authorized options, reduced to
reflect the Reverse Stock Split, being outstanding.
 
  The affirmative vote of a majority of the votes that could be cast by
stockholders who are present or represented at the Ansan Special Meeting is
required to adopt the amendment to the Ansan Stock Option Plan. Properly
executed, unrevoked proxies will be voted FOR Proposal 3 unless a vote against
Proposal 3 or abstention is specifically indicated in the proxy.
 
  THE BOARD OF DIRECTORS RECOMMENDS THAT THE STOCKHOLDERS APPROVE THE
AMENDMENT TO THE ANSAN STOCK OPTION PLAN
 
                                OTHER BUSINESS
 
  Ansan's Board of Directors does not presently intend to bring any other
business before the Ansan Special Meeting and, so far as is known to Ansan's
Board of Directors, no matters are to be brought before the Ansan Special
Meeting except as specified in the notice of the Ansan Special Meeting. As to
any business that may properly come before the Ansan Meeting or any
adjournment thereof, however, it is intended that proxies, in the form
enclosed, will be voted in the respect thereof, in accordance with the
judgment of the persons voting such proxies.
 
                                      87

                       INFORMATION CONCERNING DISCOVERY
 
  Discovery is a development stage pharmaceutical company that is focused on
acquiring, developing and commercializing proprietary, investigational drugs
that have previously been tested in humans or animals. Discovery's strategy is
to conduct preclinical and clinical studies on investigational drugs licensed
from third parties, either alone or in collaboration with corporate partners.
Discovery may also seek to enter into collaborations with corporate partners
for manufacturing and marketing of such drugs.
 
PRODUCTS AND TECHNOLOGIES UNDER DEVELOPMENT
 
SUPERVENT(TM)
 
 Background
 
  Discovery is developing SuperVent(TM) as a stable aerosolized,
multidimensional therapy for airway diseases characterized by inflammation,
injurious oxidation and excessive sputum. SuperVent's(TM) active compound is
tyloxapol, a non-anionic, alkylaryl polyether alcohol polymer which has been
safely used as an emulsifying agent in drug formulations by the United States
pharmaceutical industry for over 40 years. Tyloxapol is a slightly viscous,
amber liquid that is slowly but freely soluble in water and has a pleasant,
slightly aromatic odor. The compound is generally recognized as relatively
non-toxic to human cells and the mammalian lung. Tyloxapol had no reported
respiratory toxicity in rhesus monkeys when administered daily by aerosol for
a year at 15% weight/volume. The compound is not orally absorbed. Experimental
research conducted by Discovery's scientific founders has led to the discovery
that tyloxapol appears to possess biological activities beyond its well-
recognized emulsification properties. Tyloxapol is thought to have three
mechanisms of action:
 
  . Anti-inflammatory activity
  . Anti-oxidant activity
  . Mucolytic activity
 
  The combination of the above pharmacological activities is not presently
found in any single, safe, effective therapy for CF or chronic bronchitis. If
successfully developed and approved, SuperVent(TM) is intended to be used
daily by CF and chronic bronchitis patients in the home and hospital to
preserve pulmonary function and aid mucus expectoration.
 
  Discovery has obtained an exclusive, worldwide license from The CMHA which
covers two issued United States patents and two pending United States and
corresponding foreign patent applications relating to pharmaceutical
preparations containing high concentrations of tyloxapol and the use of
tyloxapol for the treatment of a variety of respiratory and other diseases
involving inflammation and oxidative damage. The FDA has granted orphan drug
status for the use of tyloxapol to treat CF. See "Government Regulation;
Orphan Drug Designation." Discovery has commenced clinical testing of
SuperVent(TM) for the treatment of CF at the UHSC and intends to clinically
test SuperVent(TM) for the treatment of chronic bronchitis.
 
 Cystic Fibrosis and Its Pathology
 
  CF is a progressive, lethal respiratory disease that occurs in about one out
of every 2,000 live births in the United States and Europe. CF afflicts
approximately 23,000 patients in the United States and a comparable number in
Europe. It is the most common lethal genetic disease among Caucasians. A
revolutionary improvement in the medical management of CF has allowed most
patients with the disease to live until the age of 29. The progressive
destruction of CF lungs is the major impediment to even longer survival and
improved health. A new therapy which minimizes the pulmonary complications of
CF would have a major impact on the length and quality of life of its
patients.
 
  CF results from a genetic defect in the CFTR gene. The CFTR gene codes for a
membrane protein responsible for the transport of chloride ions. Because of
this genetic defect, CF mucus is excessively viscous and adherent to airway
walls. Destruction of the lungs of CF patients occurs gradually as the
inability to clear mucus from the lungs leads to blockage of the airways
usually beginning in the smaller airways and alveoli.
 
                                      88

Impacted mucus traps foreign particles and pathogens and becomes a source of
bacterial colonization, typically with Pseudomonas aeruginosa ("Pseudomonas").
The patient's immune system responds to the chronic infection by sending
macrophages into the airways which recognize and attempt to destroy the
bacteria. These macrophages then recruit legions of neutrophils to the lungs
which activate the inflammatory transcriptional factor Nuclear Factor-kappa B
("NF-Kappa B") and initiate a cytokine-mediated inflammatory response. The
activated immune cells secrete inflammatory cytokines, oxidative chemicals and
destructive enzymes into the lungs. Repeated inflammatory and oxidative
processes initiated by macrophages and neutrophils to clear the infection are
typically ineffective and result in collateral damage to the alveoli and small
airways. Destroyed airway cells, neutrophils and macrophages then spill their
DNA and actin into the alveoli and markedly increase the viscosity and
adhesiveness of airway sputum. This debris-laden mucus, rich in proteases and
oxidants, causes the alveoli to collapse and are then replaced with
nonfunctional fibrous tissue. Eventually, a critical number of alveoli, small
airway cells and large airway cells are destroyed so that the respiratory
function of CF patients becomes insufficient to sustain life.
 
 Clinical Development Plan for SuperVent(TM) for CF
 
  Discovery's clinical development plan for SuperVent(TM) is to focus first on
CF, for which few safe and effective therapies exist. Discovery has a clinical
research agreement with UHSC and has commenced a clinical trial pursuant to
such agreement. The principal investigator of this clinical trial is Bruce C.
Marshall, M.D., Director of the CF center of the UHSC. The co-investigators
are John R. Hoidal, M.D., Chief of the Pulmonary and Pediatric Pulmonary
Divisions at UHSC, and Wayne Samuelson, M.D., Director of the Asthma Center at
UHSC. In September, 1995, the FDA approved, subject to certain modifications,
Dr. Hoidal's physician-sponsored IND application to begin this trial. The
trial, which commenced on March 17, 1997, is designed to determine whether
aerosolized SuperVent(TM) holds promise as a low toxicity, anti-inflammatory,
anti-oxidant and mucolytic agent for the treatment of CF. The specific aims of
the initial clinical study, which is presently designed in three parts, are as
follows:
 
  Part A. A dose-ranging study has been performed in ten normal human
volunteers receiving 4 ml of aerosolized SuperVent(TM) once daily to confirm a
lack of airway toxicity and establish the safe inhaled concentration of
SuperVent(TM). The preliminary results from this clinical trial have indicated
that the compound had no significant effects on any objective measure of
safety, although coughing was noted by several subjects at the highest doses
tested. Five to ten additional subjects are expected to be enrolled beginning
on or about September 15, 1997. Assessment of outcomes of Part A of the
clinical trial will include various measures of respiratory function. Should
the drug be deemed safe to study in patients with CF, Part B of the study will
proceed following approval by UHSC's institutional review board.
 
  Part B. An open study will be undertaken to establish the effects of
aerosolized SuperVent(TM) on airway physiology and lung inflammation in ten
patients with CF. Patients will be followed for two weeks while receiving 4 ml
of aerosolized SuperVent(TM) once daily. Assessment of outcomes will include
various measures of respiratory function.
 
  Part C. In the format of a six-week, multi-center, randomized, double-
blinded, placebo-controlled trial, 4 ml of aerosolized SuperVent(TM) once
daily will be studied in up to 120 patients with CF with measures of outcome
including respiratory function and physical exercise criteria.
 
  Assuming the successful completion of the Phase I/II trial, Discovery
intends to commence a multi-center, randomized, double-blinded, placebo-
controlled, Phase III clinical trial in CF and to file an additional IND to
commence a Phase II clinical trial for the treatment of chronic bronchitis.
 
 Collaboration with the Cystic Fibrosis Foundation
 
  Discovery has received assistance from the Cystic Fibrosis Foundation in
assembling a CF medical advisory board to advise on the design of the Phase
I/II clinical trial in CF. The Cystic Fibrosis Foundation does not
 
                                      89

endorse investigational drugs but does lend its support to companies
conducting clinical trials in CF. If successful in obtaining such support,
Discovery intends to utilize the assistance of the Cystic Fibrosis
Foundation's patient registry to coordinate a multi-center Phase III clinical
trial. If the Phase III trial is successful and regulatory approval to market
SuperVent(TM) is obtained, Discovery plans to utilize the Cystic Fibrosis
Foundation to distribute the product in the United States and Canada.
 
CURRENT RESPIRATORY THERAPIES FOR CYSTIC FIBROSIS
 
 Supportive Care and Traditional Drug Therapies
 
  The standard treatment for enhancing expectoration of CF sputum is postural
drainage and chest percussion. In this daily procedure, patients lie in an
inclined position with their head below their chest. The patient's chest is
then repeatedly and gently pounded for several minutes with a cupped hand by a
care giver. While modestly efficacious, postural drainage and chest percussion
is labor intensive and requires a care giver.
 
  When mucus becomes colonized with bacteria such as Pseudomonas and other
pathogens, a variety of intensive oral, intravenous and aerosolized
antibiotics are administered. Repeated use of these antibiotics to clear the
infection often results in strains of Pseudomonas which are resistant to the
antibiotics. Over time, many CF patients become chronically colonized with
drug resistant Pseudomonas. The ensuing cytokine-mediated inflammatory and
oxidative process then accelerates the destruction of the lungs.
 
 Pulmozyme(TM)
 
  Standard daily pharmacological therapy for airway obstruction in CF
presently consists largely of inhaled Pulmozyme(TM) (recombinant human rhDNase
or dornase alfa). This drug has been marketed by Genentech in the United
States and Canada since early 1994. Pulmozyme(TM) reduces the viscosity of CF
mucus by cleaving the DNA released from destroyed inflammatory, epithelial and
bacterial cells which collect in mucus and contribute to its abnormal
viscosity and adherence. The drug provides a small improvement in lung
function and a slight reduction in the number of days requiring intravenous
antibiotics for respiratory infections. The approximate yearly cost of
Pulmozyme(TM) treatment for an average patient is $11,000. Genentech's 1995
sales of Pulmozyme(TM) are estimated to have been approximately $110 million.
 
 Lung Transplant
 
  Lung transplantation is the final option for CF patients suffering from
severely compromised respiratory function. However, there is an extremely
limited supply of transplantable lungs and the operation is very costly. In
addition, there is an increased risk of death from such a major surgical
procedure and a long and painful recovery. Furthermore, patients who do
recover must take immunosuppressive drugs for the rest of their life to
prevent organ rejection, making them vulnerable to infections.
 
SUPERVENT(TM) FOR CHRONIC BRONCHITIS
 
  In the event of the successful completion of the Phase I/II trial of
SuperVent(TM) in CF, Discovery may file an IND to commence a Phase II clinical
trial for the use of SuperVent(TM) to treat chronic bronchitis. Chronic
bronchitis is a major medical problem that is characterized by inflammation of
the airways leading to cough and increased mucus production. The condition
afflicts approximately 14,000,000 patients in the United States. Two primary
causes of chronic bronchitis are habitual smoking and air pollution. Non-
specific irritants contained in cigarette smoke and air pollution result in an
increased number of macrophages entering into the lungs. The macrophages
become activated and secrete inflammatory cytokines which recruit neutrophils
that together release oxidants and elastase, an enzyme which degrades a
structural component of the lungs, elastin. These released oxidants and free
radicals oxidize alpha1-antitrypsin which normally inactivates elastase. In
addition, elastin repair may be inhibited by cigarette smoke leading to
structural changes in the lung that may significantly compromise respiratory
function.
 
                                      90

  Based on clinical studies and other studies conducted by persons affiliated
and unaffiliated with Discovery, Discovery believes that high concentrations
of tyloxapol may improve pulmonary function in chronic bronchitis patients.
SuperVent's(TM) active compound, tyloxapol, is also a component of
Exosurf(TM), a product that has been clinically tested to treat chronic
bronchitis. The chemical composition of Discovery's SuperVent(TM) product is
substantially different from that of Exosurf(TM). SuperVent(TM) contains a
substantially higher concentration of tyloxapol in a phosphate-buffered saline
solution. Exosurf(TM) is composed of tyloxapol, cetyl alcohol,
dipalmetoylphosphatitylcholine and sodium chloride. Exosurf(TM), as prepared
for use in treating chronic bronchitis, was, to Discovery's knowledge,
difficult to satisfactorily aerosolize. SuperVent(TM) can be aerosolized and
successfully delivered through a nebulizer.
 
HISTORY OF SAFE USE
 
  Tyloxapol has been safely used by the pharmaceutical industry for over 40
years as an emulsifying agent in various drug formulations containing
concentrations of tyloxapol lower than those intended to be present in
Discovery's SuperVent(TM) product. Sterling Pharmaceuticals ("Sterling")
previously marketed in the United States a formulation containing low
concentrations of tyloxapol (0.125% by volume) as an expectorant for chronic
bronchitis under the trade name Alevaire(TM). Alevaire(TM) was first approved
for use in the United States in the late 1940's in children with pulmonary
tuberculosis as an aerosol delivery vehicle for streptomycin, an antibiotic.
At that time, in vitro (i.e., non-animal) studies indicated that sodium
bicarbonate and tyloxapol increased susceptibility of tuberculosis to
streptomycin. Alevaire(TM) has been inhaled by children with tuberculosis for
two hours a day for up to six months without adverse effects. In a group of
adult tuberculosis patients, Alevaire's(TM) expectorant properties were noted
when it was reported that thick, viscous mucus became thin and watery upon
administration. Alevaire(TM) has been used as a mucolytic treatment for a
variety of respiratory conditions. Based on published literature, Alevaire(TM)
has no reported adverse effect on bacterial host-defense mechanisms and has
even been locally infused into humans to hasten resolution of infected joints
and pacemaker pockets.
 
  Alevaire's(TM) marketing was discontinued by Sterling in 1981. At that time,
passage of the Harris-Kefauver amendment to the Food and Drug Act mandated
that older drugs previously approved only on the basis of safety, the
regulatory standard at the time, were required to demonstrate efficacy to
continue to be marketed. Because only anecdotal reports of efficacy and not
controlled studies were available to support Alevaire's(TM) use in respiratory
diseases, it was ruled that there was insufficient data to permit the
product's continued use without further studies. Sterling apparently elected
to withdraw the drug from the United States market, presumably because its
patent had expired. Alevaire(TM) is still marketed in Japan by Nippon Shoju
Co., Ltd. At the present time, tyloxapol, in addition to being used in the
surfactant Exosurf(TM), is included as an "inactive" ingredient in the over-
the-counter medications Vicks Sinex(TM) and Visex(TM), which are marketed by
Procter & Gamble, Inc. A review of the literature by Discovery does not
indicate that Alevaire(TM) was ever tested as an anti-oxidant or used to treat
CF.
 
KL/4/-SURFACTANT TECHNOLOGY
 
 Background
 
  Lung surfactants are protein-phospholipid complexes which coat the alveoli
(air sacs) of the lungs. Alveoli are delicate, balloon-like sacs in the lungs
where gaseous exchange occurs. Lung surfactants lower surface tension in
expiration and raise it during inspiration to prevent the collapse of alveoli.
Replacement surfactants are currently used mainly to treat IRDS. Infants with
this condition, as well as infants born with meconium in their lungs, which
can lead to MAS, and patients with ARDS, typically suffer from insufficient
surfactant that leads to a life-threatening loss of pulmonary function.
 
  KL/4/-Surfactant is a proprietary, synthetic lung surfactant that was
originally invented at Scripps by Charles G. Cochrane, M.D., et al. KL/4/-
Surfactant is an aqueous suspension of lipid vesicles containing the novel
synthetic
 
                                      91

peptide KL/4/. The "K" represents the water-soluble amino acid lysine and the
"L" represents the fat-soluble amino acid leucine. KL/4/-Surfactant is
patterned after human Surfactant Protein B, shown to have the greatest
surfactant activity in humans. Human Surfactant Protein B acts by forming a
stable monolayer on the inner surface of the pulmonary alveoli and preventing
their collapse. The product was exclusively licensed to J&J, which led its
development from 1991 until its license to ATI. J&J completed a multi-center,
Phase II clinical trial of KL/4/-Surfactant in 47 infants with IRDS. This
trial demonstrated safety and efficacy comparable to that of the bovine-
derived surfactant, Survanta(TM), marketed by Ross Laboratories.
 
  Discovery's majority-owned subsidiary, ATI, has acquired the exclusive
worldwide sublicense to the KL/4/-Surfactant technology from J&J and J&J's
wholly owned subsidiary, Ortho Pharmaceutical Corporation ("Ortho"). ATI
believes that as a peptide-containing, synthetic lung surfactant, KL/4/-
Surfactant will be superior to the non-protein-containing surfactant,
Exosurf(TM), marketed by Glaxo-Wellcome. ATI further believes that KL/4/-
Surfactant will be as effective as or superior to the animal-derived, protein-
containing surfactants, Survanta(TM) (bovine-derived) and InfaSurf(TM) (calf-
derived, being developed by Forest Laboratories). In addition, ATI believes
that synthetic surfactants will be far less expensive to produce and will not
have the viral/prion (suspected to cause "Mad Cow Disease") contamination and
immunogenicity concerns associated with animal-derived proteins. ATI further
believes that a lower cost of production may make the use of lung surfactants
economically feasible for adult indications such as ARDS.
 
TARGET DISEASE INDICATIONS
 
  ATI intends to initially develop the KL/4/-Surfactant technology for the
treatment of MAS and ARDS. ATI may also develop the KL/4/-Surfactant
technology for the treatment of IRDS.
 
 Meconium Aspiration Syndrome.
 
  MAS affects approximately 26,000 newborn infants per year in the United
States alone. The disease results from the release of meconium, a greenish,
pasty constituent of the fetal bowel, into the amniotic fluid. Meconium is
then aspirated into the fetal lungs. The presence of meconium in the infant's
lung after delivery often leads to pneumonitis, a generalized inflammation of
the lungs, which can result in death. This inflammation degrades lung
surfactant and results in insufficient pulmonary function. Presently, there
are no products specifically approved for this condition. Treatment consists
of general supportive care. Approximately one-third of the infants with MAS
require extra-corporeal membrane oxygenation therapy ("ECMO").
 
 Adult Respiratory Distress Syndrome.
 
  ARDS is a generalized inflammatory disease of the lungs marked by intense
leukocytic infiltration, edema and atelectasis (partial lung collapse).
Endogenous surfactant in the lung is degraded from this inflammatory cascade
leading to further loss of the epithelial cells that make surfactant. The
initiating factors of ARDS are numerous and include head injury, aspiration of
gastric contents and other noxious fluids, trauma, smoke inhalation and broken
bones. Patients typically require mechanical ventilation and are at risk of
developing multiple organ failure. Mortality has remained at approximately
50%. There is no FDA-approved therapy outside of general supportive care. The
incidence is approximately 150,000 patients per year in the United States.
 
 Infant Respiratory Distress Syndrome.
 
  IRDS is primarily a disease of premature infants. These infants are born
prior to the synthesis of adequate amounts of pulmonary surfactant proteins.
The disease affects 40,000 to 50,000 infants per year in the United States and
an equal number in Europe. Twenty to forty percent of infants with IRDS
develop debilitating bronchopulmonary dysplasia requiring extended ventilatory
support and hospitalization. The cost of caring for these infants can exceed
$100,000 per patient. Therapy shortly after birth with animal-derived
surfactants has proven to be effective in liberating infants from mechanical
ventilation or abbreviating the period of ventilation. Surfactant therapy has
reduced the historical mortality rate by more than half to about 10%.
 
                                      92

COMPETITIVE ASSESSMENT
 
  Presently, there are no approved drugs that are specifically indicated for
MAS or ARDS. Current therapy consists of general supportive care and
mechanical ventilation. Three products are specifically approved for the
treatment of IRDS. Exosurf(TM), which contains only phospholipids and
synthetic organic detergents and no stabilizing protein or peptides, is
marketed by Glaxo Wellcome. Survanta(TM), which has been shown to be more
effective than Exosurf(TM) in clinical trials, is an extract of bovine lung
that contains the cow version of Surfactant Protein B. Recently, Forest
Laboratories obtained an approvable letter from the FDA for its calf lung
surfactant, Infasurf(TM), for use in IRDS. Although none of the three approved
surfactants for IRDS is approved for ARDS, which is a significantly larger
market, there are a significant number of other potential therapies in
development for the treatment of ARDS that are not surfactant related. Any of
these various drugs or devices could significantly impact the commercial
opportunity for KL/4/-Surfactant.
 
DEVELOPMENT STATUS
 
 Infant Respiratory Distress Syndrome
 
  In July 1992, an IND was submitted to the FDA by Charles G. Cochrane, M.D.
of Scripps, the inventor of KL/4/-Surfactant and a consultant to ATI. The IND
sought to evaluate the safety and efficacy of KL/4/-Surfactant in the
treatment of IRDS. A total of 47 infants with IRDS were treated with KL/4/-
Surfactant in this multi-center, Phase II clinical trial. The pulmonary
function of the infants, measured as a ratio (a/A) of arterial oxygen
concentration (a) as a function of the concentration of the inspired oxygen
(A), averaged 0.14 (severe respiratory distress) and rose to the normal range
(>0.40) within 12 hours of treatment. Airway pressures were reduced over this
period and the infants were removed from supportive mechanical ventilation in
a mean time of five days. There were no IRDS-related deaths in the trial.
 
 Adult Respiratory Distress Syndrome
 
  Dr. Cochrane and his colleagues at Scripps have developed an adult animal
model of ARDS. In every case with this model, KL/4/-Surfactant treatment
appeared to re-expand the lungs and induce an elevation of arterial oxygen
partial pressure from < 100 mmHg to > 400 mmHg within two hours. These
experimental results suggest that KL/4/-Surfactant has the potential to treat
patients with this life-threatening condition. In addition, pilot clinical
studies on ARDS patients conducted by researchers unaffiliated with ATI or its
scientific founders using animal-derived surfactants demonstrated safety and
efficacy. Scientists at Justus-Liebig University in Germany conducted a
clinical study and concluded that the bronchoscopic application of a high dose
of surfactant, aimed at overcoming inhibitory factors in the alveolar space of
the patients, may offer a feasible and safe approach to improving gas exchange
in severe ARDS patients. The results of this study were published during 1996
in the American Journal of Critical Care Medicine.
 
 Meconium Aspiration Syndrome
 
  Dr. Cochrane and his colleagues at Scripps have developed a potential method
of preventing MAS by lavaging meconium-filled lungs with diluted KL/4/-
Surfactant. In the lungs of adult rabbits and newborn rhesus monkeys, the
lavage not only removed much of the meconium, but it also immediately expanded
the lungs and allowed for greater respiration within minutes. The results of
these experimental studies suggest that prophylactic KL/4/-Surfactant
administration has the potential to eliminate MAS in newborn infants at risk
of developing this life- threatening condition.
 
INVESTMENT IN ACUTE THERAPEUTICS, INC.; LICENSE OF KL/4/-SURFACTANT TECHNOLOGY
 
  On October 28, 1996, Discovery completed a transaction pursuant to which it
invested $7.5 million in a new majority-owned subsidiary, ATI, in exchange for
600,000 shares of Series A Convertible Preferred Stock of ATI, initially
representing 75% of the outstanding voting securities of ATI following such
transaction.
 
                                      93

   
Concurrent with Discovery's investment in ATI, J&J, Ortho and ATI entered into
an agreement (the "J&J License Agreement") granting an exclusive sublicense of
the KL/4/-Surfactant technology to ATI in exchange for certain license fees,
royalties and 40,000 shares of Common Stock of ATI, representing approximately
5% of the outstanding voting securities of ATI. J&J also contributed its
existing KL/4/-Surfactant raw material inventory and specialized manufacturing
equipment to ATI in exchange for shares of nonvoting Series B Preferred Stock
of ATI having a $2.2 million liquidation preference, which liquidation
preference was subsequently reduced to $2.039 million pursuant to a purchase
price adjustment. In exchange for its consent to the J&J License Agreement,
Scripps received 40,000 shares of Common Stock of ATI comprising approximately
5% of the outstanding voting securities of ATI.     
 
  Pursuant to agreements entered into by the founding management of ATI,
members of founding management were granted options to purchase an aggregate
of 84,800 shares of Common Stock of ATI. Each founder was granted two options:
a Restricted Option and a Basic Option (each as defined below). The
"Restricted Options" cover an aggregate of 44,800 shares of Common Stock of
ATI, at an exercise price of $0.01 per share, and will be exercisable on the
fifth anniversary of the date of grant (or earlier upon the occurrence of an
Acceleration Event). An "Acceleration Event" includes any equity financing of
ATI, certain debt financings, or a merger or sale of substantially all of the
assets of ATI. If an Acceleration Event occurs prior to the fifth anniversary
of the grant date, the Restricted Options will be exercisable based on the
valuation of ATI in the Acceleration Event, as set forth below:

              VALUATION OF ATI FOLLOWING,
           OR CONSIDERATION RECEIVED IN, THE      PERCENTAGE OF TOTAL RESTRICTED
                   ACCELERATION EVENT               OPTION SHARES ACCELERATED
           ---------------------------------      ------------------------------
                                               
         Less than $65 million...................                0%
         Over $65 million........................               25%
         Over $75 million........................               50%
         Over $85 million........................               75%
         Over $95 million........................              100%

  The "Basic Options" cover an aggregate of 40,000 shares of Common Stock of
ATI at an exercise price of $0.32 per share, and are fully exercisable. Since
its formation, ATI has granted additional options to its executive personnel
and Discovery. As a result, Discovery currently owns approximately 60% of the
equity of ATI on a full-diluted basis.
 
  In connection with Discovery's investment in ATI, all of the stockholders of
ATI entered into a Co-sale Agreement. Under the terms of the Co-sale
Agreement, if a stockholder of ATI proposes to sell any shares of stock of ATI
(with certain exceptions), each other stockholder has the right to participate
pro rata in such sale. The Co-sale Agreement terminates upon the consummation
of an underwritten public offering of Common Stock of ATI, an acquisition of
ATI or certain insolvency proceedings.
 
DEVELOPMENT PLAN/SPONSORED RESEARCH AGREEMENT
 
  ATI currently has an approved IND for ARDS. ATI has received FDA approval to
amend the approved IND and to re-initiate Phase II clinical trials of KL/4/-
Surfactant for the treatment of ARDS. A Phase I/II clinical trial in nine
patients with ARDS has been initiated. ATI has amended its existing IRDS IND
to permit the initiation of Phase II clinical trials in MAS. On May 27, 1997,
ATI commenced a Phase II clinical trial in MAS at Thomas Jefferson University
Hospital in Philadelphia. The study is designed to enroll 30 newborn babies
with MAS, of which 20 will be randomized to receive KL/4/-Surfactant, now
called Surfaxin. The remaining ten MAS babies will receive the standard of
care. Orphan drug status for MAS, ARDS and IRDS has been granted by the FDA.
 
  ATI and Scripps have entered into a sponsored research agreement (the
"Sponsored Research Agreement") supporting continuing research by Charles G.
Cochrane, M.D., and Susan Revak of Scripps. Pursuant to the Sponsored Research
Agreement, ATI will contribute $460,000 annually to Scripps' KL/4/-Surfactant
research
 
                                      94

efforts for an initial two-year period. ATI has an option to acquire an
exclusive worldwide license to make, have made, sell or use technology
developed under the agreement, which it is required to exercise within 180
days from receipt of notice from Scripps of the development of such
technology. Scripps will own all technology that it develops pursuant to work
performed under the proposed Sponsored Research Agreement. ATI has the right
to receive 50% of the net royalty income received by Scripps for inventions
jointly developed by ATI and Scripps to the extent ATI does not exercise its
option with respect to such inventions.
 
  ATI has entered into consulting agreements with certain key research
personnel at Scripps.
 
ST-630
 
 Background
 
  ST-630 is an analog of the active circulating vitamin D hormone calcitriol
modified to increase its potency and lengthen its circulating half-life. As a
class, vitamin D analogs are commonly used therapies in Europe and Japan for
osteoporosis. In aggregate, this class of compounds is believed to generate
about several hundred million dollars in worldwide sales for osteoporosis.
Published studies have confirmed the efficacy of vitamin D analogs in
increasing bone mass and decreasing fractures. Vitamin D analogs, however,
have not been well accepted in the United States due to certain side effects
in the compounds currently marketed. Specifically, prior studies of vitamin D
analogs have been associated with hypercalcemia in a percentage of patients.
Hypercalcemia is elevated calcium levels in the blood above a generally
accepted range. Discovery believes that this risk of hypercalcemia may be the
primary reason why active vitamin D analogs have only been tested on a limited
basis in the United States, which is generally considered to be a high calcium
consumption country. No vitamin D analogs are currently marketed for
osteoporosis in the United States. Because Discovery has not completed a Phase
I clinical study of ST-630, Discovery has not yet determined whether ST-630
represents a risk of hypercalcemia at any dosage levels that may prove
efficacious for treating postmenopausal osteoporosis.
 
  Discovery has the WARF License Agreement with WARF relating to ST-630 and
its use in treating postmenopausal osteoporosis. Discovery believes that ST-
630 may have an improved pharmacological profile compared to earlier, active
vitamin D analogs, although there can be no assurance of this. Sumitomo and
Taisho have jointly licensed the right to develop, manufacture and market ST-
630 in Japan for the treatment of osteoporosis and are presently conducting
the equivalent of a Phase II clinical study of this drug in Japan. Discovery
has access to the preclinical data generated by Sumitomo and Taisho pursuant
to the terms of the WARF License Agreement. Discovery intends to seek FDA
approval to initiate a Phase I clinical study of ST-630 as a once-daily,
orally administered drug for the treatment of osteoporosis in the United
States. Discovery has not had any discussions with the FDA regarding ST-630,
however, and there can be no assurance that such approval will be granted.
Discovery believes that ST-630 could be administered in combination with other
approved drugs for osteoporosis. The composition of matter patent covering ST-
630 expires in 2001. A patent covering the use of ST-630 to treat
postmenopausal osteoporosis recently issued in the United States. See "--
Patents, Licenses and Proprietary Rights."
 
 Postmenopausal Osteoporosis
 
  Postmenopausal osteoporosis is a disease of postmenopausal women
characterized by decreased bone mass which leads to reduced bone strength and
an increased risk of fractures. Typically, fractures occur in the weight-
bearing bones of the vertebrae and the hip. On average, women have 10% to 25%
less bone mass than men at maturity. When menopause occurs, the production of
estrogen diminishes and women experience accelerated bone loss. In the United
States, 7 to 20 million women are at risk for developing postmenopausal
osteoporosis. In the context of other diseases, a woman's risk of developing a
hip fracture is equal to her combined risk of developing breast, uterine and
ovarian cancer. One out of every five persons who has a hip fracture will not
survive more than one year. In addition, one-third of all patients with hip
fractures will become totally dependent and one-half will need assistance with
walking. The annual cost of acute care associated with osteoporosis in the
United States is estimated to be in excess of $10 billion.
 
                                      95

 Approved Therapies for Osteoporosis
 
 Estrogen
 
  Estrogen is of proven benefit in treating osteoporosis in postmenopausal
women. However, it is associated with significant adverse effects which limit
its use for osteoporosis. Estrogen replacement therapy for postmenopausal
women can cause hot flashes, menstruation (when taken with progesterone) and,
more seriously, may increase the risk of breast and uterine cancer. Extensive
use of Vitamin D analogs in Europe and Japan has not revealed any association
of Vitamin D analogs with any of these significant adverse side effects.
Estrogen must be continually taken or the accumulated bone mass is quickly
lost.
 
 Fosamax(TM)
 
  Fosamax(TM) (alendronate), from Merck, is the first approved osteoporosis
drug in the United States of the bisphosphonate class. (Bisphosphonates are
inhibitors of bone resorption mediated by a class of cells called
osteoclasts.) The drug is incorporated into bone and prevents calcium in bone
from being reabsorbed. While clinical studies have demonstrated increases in
bone mass leading to decreased hip and vertebral fractures when the drug is
taken for three years, the long-term safety questions of the drug, which is
believed to remain in the body for up to a decade are unknown. Many other
bisphosphonates are in late-stage clinical testing for osteoporosis.
Fosamax(TM) has also been associated with acute esophagitis in some patients.
To limit the risk of developing this painful and dangerous condition, patients
must take the pill upon awakening in the morning with a full glass of water,
remain in a standing position, avoid food for at least half an hour and then
consume a full breakfast. Vitamin D analogs have not been associated with
acute esophagitis.
 
 Nasal Calcitonin
 
  Miacalcin(TM) as sold by Sandoz Pharmaceuticals is a nasally administered
calcitonin. While the injectable form of calcitonin has proven to be safe and
effective for reducing bone pain associated with vertebral fractures, the
amount of increase in bone mass is relatively modest. Miacalcin(TM) has never
been shown to decrease the risk of fractures.
 
 Vitamin D and Calcium Supplementation
 
  Currently, vitamin D and calcium supplementation is being studied in a
45,000 patient Women's Health Initiative open label study. Given earlier,
smaller studies which have been completed, Discovery believes that this study
will most likely confirm a modest benefit to increasing bone mass when
administered to younger women. Older women and men will probably not benefit
from this therapy as it is thought that the kidney's ability to convert
vitamin D to the active form is compromised with age.
 
 Therapies in Development for Osteoporosis
 
 Slow-Release Sodium Fluoride
 
  Slow-release sodium fluoride is being developed by Mission Pharmacal. In a
small study, women on this compound increased bone in their hip and spine and
had fewer fractures. However, high doses of sodium fluoride, which had been
previously studied in a non slow-release formulation, caused peptic ulcers and
built brittle bone. Vitamin D analogs are not known to cause any of these side
effects. It is thought that patients taking sodium fluoride will need to be
monitored to ensure that their blood fluoride levels stay below toxic levels.
 
 Small Molecule Estrogen Agonists/Antagonists
 
  Raloxifene (being developed by Eli Lilly) and droloxifene (being developed
by Pfizer) are small molecule estrogen agonists/antagonists which may offer
estrogen's therapeutic benefit to bone without increasing the risk of breast
and uterine cancer. The efficacy and adverse effect profile of these compounds
in comparison to estrogen are still being studied in late stage clinical
trials.
 
                                      96

DEVELOPMENT PLAN
 
  Discovery has access for regulatory purposes to preclinical data already
generated by Sumitomo and Taisho with respect to ST-630 pursuant to the terms
of the WARF License Agreement. Discovery intends to seek FDA approval to
initiate clinical studies of ST-630 as a once-daily, orally administered drug
for the treatment of postmenopausal osteoporosis in the United States. An IND
is being prepared for submission to the FDA during the third quarter of 1997.
Following FDA clearance, if given, Discovery intends to conduct an initial
dose-ranging study of ST-630 in humans. Based upon the results of the dose-
ranging study, Discovery may then either seek to further optimize the delivery
of ST-630 by testing one or more alternative means of delivery or, assuming
acceptable results, seek to initiate a large-scale clinical trial in the
United States with effect on bone mineral density being the primary endpoint.
Discovery has had no interaction with the FDA to date regarding ST-630 and
there can be no assurance that Discovery's planned clinical trial of ST-630
will receive the requisite regulatory approvals.
 
                      GOVERNMENT REGULATION; ORPHAN DRUG
 
  The testing, manufacture, distribution, advertising and marketing of drug
products are subject to extensive regulation by governmental authorities in
the United States and other countries. Prior to marketing, any pharmaceutical
products developed or licensed by Discovery must undergo an extensive
regulatory approval process required by the FDA and by comparable agencies in
other countries. This process, which includes preclinical studies and clinical
trials of each pharmaceutical compound to establish its safety and efficacy
and confirmation by the FDA that good laboratory, clinical and manufacturing
practices were maintained during testing and manufacturing, can take many
years, requires the expenditure of substantial resources and gives larger
companies with greater financial resources a competitive advantage over
Discovery. The FDA review process can be lengthy and unpredictable, and
Discovery may encounter delays or rejections of its applications when
submitted. If questions arise during the FDA review process, approval may take
a significantly longer period of time. Generally, in order to gain FDA
approval, a company first must conduct preclinical studies in a laboratory and
in animal models to obtain preliminary information on a compound's efficacy
and to identify any safety problems. The results of these studies are
submitted as part of an IND application that the FDA must review before human
clinical trials of an investigational drug can start.
 
  Clinical trials are normally done in three phases and generally take two to
five years or longer to complete. Typically, clinical testing involves a
three-phase process. Phase I consists of testing the drug product in a small
number of humans to determine preliminary safety and tolerable dose range.
Phase II involves larger studies to evaluate the effectiveness of the drug
product in humans having the disease or medical condition for which the
product is indicated and to identify possible common adverse effects in a
larger group of subjects. Phase III consists of additional controlled testing
to establish clinical safety and effectiveness in an expanded patient
population of geographically dispersed test sites, to evaluate the overall
benefit-risk relationship for administering the product and to provide an
adequate basis for product labeling.
 
  After completion of clinical trials of a new drug product, FDA and foreign
regulatory authority marketing approval must be obtained. NDAs submitted to
the FDA generally take one to three years to obtain approval. If questions
arise during the FDA review process, approval may take a significantly longer
period of time. The testing and approval processes require substantial time
and effort and there can be no assurance that any approval will be granted on
a timely basis, if at all. Even if regulatory clearances are obtained, a
marketed product is subject to continual review, and later discovery of
previously unknown problems or failure to comply with the applicable
regulatory requirements may result in restrictions on the marketing of a
product or withdrawal of the product from the market as well as possible civil
or criminal sanctions. For marketing outside the United States, Discovery also
will be subject to foreign regulatory requirements governing human clinical
trials and marketing approval for pharmaceutical products. The requirements
governing the conduct of clinical trials, product licensing, pricing and
reimbursement vary widely from country to country. None of Discovery's
products under development have been approved for marketing in the United
States or elsewhere. No assurance can be given
 
                                      97

that Discovery will be able to obtain regulatory approval for any such
products under development. Failure to obtain requisite governmental approvals
or failure to obtain approvals of the scope requested will delay or preclude
Discovery or its licensees or marketing partners from marketing their
products, or limit the commercial use of the products, and thereby could have
a material adverse effect on Discovery's business, financial condition and
results of operations.
 
  In March 1995, Discovery's scientific founders obtained from the FDA an
orphan drug designation for the use of tyloxapol to treat CF. In addition,
orphan drug status for the use of KL/4/-Surfactant to treat MAS, ARDS and IRDS
has been granted by the FDA. Under the Orphan Drug Act, the FDA may grant
orphan drug designation to drugs intended to treat a "rare disease or
condition," which generally is defined as a disease or condition that affects
populations of fewer than 200,000 individuals in the United States. If
Discovery is the first sponsor to receive FDA approval to market tyloxapol to
treat CF, or to market KL/4/-Surfactant to treat MAS, ARDS or IRDS, the orphan
drug designation will, under current law, entitle Discovery to a seven-year
period of marketing exclusivity in the United States during which the FDA,
subject to certain limitations, will not approve another application for the
same drug for the same indication. There can be no assurance that Discovery
will ever receive FDA approval to market SuperVent(TM) to treat CF or to
market KL/4/-Surfactant to treat MAS, ARDS or IRDS, and thus there can be no
assurance that Discovery will obtain the benefits of any of the aforementioned
orphan drug designations. While orphan drug designation and marketing approval
may be advantageous to Discovery, if achieved, there can be no assurance that
the scope of protection or the level of exclusivity that is currently afforded
by such designation and approval will remain in effect in the future. In
addition, competitors of Discovery may obtain orphan drug designation for
product candidates that are not the same as SuperVent(TM) or KL/4/-Surfactant
though they are intended to treat the same indications. Discovery may request
orphan drug designation, if applicable, for more of its products or additional
indications as part of its overall regulatory strategy in the future.
 
                                      98

                   PATENTS, LICENSES AND PROPRIETARY RIGHTS
 
  Discovery's success will depend in part on patent and trade secret
protection for its technologies, products and processes, and on its ability to
operate without infringing the proprietary rights of other parties both in the
United States and in foreign countries. Because of the substantial length of
time and expenses associated with bringing new products through development to
the marketplace, the pharmaceutical industry places considerable importance on
obtaining and maintaining patent and trade secret protection for new
technologies, products and processes. The failure to obtain and maintain
patent protection could mean that Discovery would face increased competition
in the United States and in foreign countries.
 
LICENSING ARRANGEMENTS
 
 CMHA License Agreement: SuperVent(TM)/Tyloxapol
 
  Discovery depends on its license with CMHA (the "CMHA License Agreement")
for the core technology relating to its SuperVent(TM) product under
development. The CMHA License Agreement grants Discovery an exclusive
worldwide license (including the right to sublicense) to develop, make and
sell products which are covered in whole or in part by a valid claim contained
in the two issued United States patents (United States Patent No. 5,474,760
issued December 12, 1995 and United States Patent No. 5,512,270 issued April
30, 1996) and two pending United States patent applications held by CMHA and
licensed to Discovery under the CMHA License Agreement, and any later-issued
United States and any foreign patents based on or issuing from the issued
patents and the pending patent applications. The United States patents cover
methods of using tyloxapol, the active compound in SuperVent(TM), to treat
cystic fibrosis and methods of treating disease caused by oxidant species,
such as myocardial infarction, stroke and ARDS. The two pending United States
patent applications relate to the use of tyloxapol as an anti-inflammatory and
anti-oxidant agent. Two international applications have been filed under the
Patent Cooperation Treaty, and certain corresponding foreign national
applications are pending. These applications claim, inter alia, the use of
tyloxapol to treat cystic fibrosis and the use of tyloxapol as an anti-oxidant
and anti-inflammatory agent. CMHA's United States patents expire in 2013. The
CMHA License Agreement is terminable by CMHA: (i) on 60 days' prior notice
upon Discovery's failure to make timely payments, reimbursements or reports,
if the failure is not cured by Discovery within 60 days, or (ii) on 90 days'
prior notice upon any material breach or default by Discovery, if the default
or breach is not cured by Discovery within 90 days. The termination of the
CMHA License Agreement, or the failure to obtain and maintain patent
protection for Discovery's technologies, would have a material adverse effect
on Discovery's business, financial condition and results of operations.
 
  In consideration of the license granted to Discovery by CMHA, Discovery (i)
has agreed to pay CMHA (a) royalties on net sales by Discovery and by any
sublicensees of Discovery of products covered by the licensed technology, and
(b) a percentage of any sublicense fees or similar amounts (other than
research and development payments) paid to Discovery by any sublicensees, and
(ii) is responsible for the cost of filing and prosecuting patent applications
and maintaining issued patents. The CMHA License Agreement will terminate upon
the expiration of the last to expire of the licensed patents.
 
 J&J License Agreement: KL/4/-Surfactant
 
  Pursuant to the J&J License Agreement, ATI has received an exclusive,
worldwide license to commercialize KL/4/-Surfactant and the other licensed
technology for the diagnosis, prevention or treatment of disease, including
the right to further sublicense such technology. The exclusive license granted
to ATI is a sublicense under certain patent rights previously licensed to J&J
by Scripps (the "Scripps Patent Rights") and a license under certain other
patent rights held by J&J's Ortho division (the "Ortho Patent Rights" and,
together with the Scripps Patent Rights, the "KL/4/ Patent Rights"). In
addition to granting an exclusive sublicense to ATI, J&J has transferred its
existing KL/4/-Surfactant raw material inventory and specialized manufacturing
equipment to ATI in exchange for Non-Voting Series B Preferred Stock of ATI.
 
                                      99

  ATI paid a $200,000 license fee to J&J upon execution of the J&J License
Agreement. In addition, ATI will pay J&J a royalty on net sales of KL/4/-
Surfactant sold by it or its sublicensees. The J&J License Agreement further
provides for the making of milestone payments as follows: $250,000 upon the
filing of the first NDA for a product in a neonatal indication; $500,000 upon
approval of the first NDA for a product in a neonatal indication; $500,000
upon filing of the first NDA for a product in the ARDS indication; and
$1,500,000 upon approval of the first NDA for a product in the ARDS
indication. Royalties are payable for a minimum period of ten years from the
first commercial sale of a product in each country and, thereafter (if
applicable) until expiration of the last to expire of the KL/4/ Patent Rights
in such country, after which time ATI will have a fully paid license.
 
  The Scripps Patent Rights consist of three issued United States patents and
two pending United States applications. The three issued patents are United
States Patent No. 5,407,914, issued April 18, 1995; U.S. Patent No. 5,260,273,
issued November 9, 1993; and U.S. Patent No. 5,164,369, issued November 17,
1992. These patents relate to synthetic pulmonary surfactants (including
KL/4/-Surfactant), certain related polypeptides and a method of treating
respiratory distress syndrome with these surfactants. The first of these
patents will expire in 2009. The two pending United States applications relate
to pulmonary surfactants, related polypeptides, liposomal surfactant
compositions and methods of treating respiratory distress syndromes with these
surfactants and compositions. Corresponding foreign patent applications are
pending in the European Patent Office, certain European countries, Canada and
Japan. Two patents have issued in Australia and one patent has issued in
Norway. Discovery believes that the respiratory distress syndromes covered by
these patents and patent applications include MAS, ARDS and IRDS. Scripps is
responsible for filing, prosecuting and maintaining the Scripps Patent Rights
and J&J is required to reimburse Scripps for the costs of such filings,
prosecution and maintenance. The Ortho Patent Rights consist of certain
pending United States patent applications which relate to methods of
manufacturing certain peptides which may be used in the manufacture of KL/4/-
Surfactant. J&J is responsible for filing, prosecuting and maintaining the
Ortho Patent Rights.
 
 WARF License Agreement: ST-630
 
  Pursuant to the WARF License Agreement, Discovery has an exclusive license
within all countries in the Western hemisphere, including the right to
sublicense, in the field of prevention, treatment, amelioration or cure of
bone disease, under U.S. Patent No. 4,358,406 (the "ST-630 Patent") covering
the compound ST-630 and U.S. Patent No. 5,571,802 covering a method for
treating postmenopausal osteoporosis (the "ST-630 Use Patent"). In addition,
Discovery has an option to extend the exclusive license to the remaining
countries of the world with the exception of Japan. Discovery's option expires
on January 1, 2002 and, with respect to Argentina, Spain, Portugal and Korea,
must be exercised prior to the commencement of product development therein.
 
  Discovery paid a one-time fee of $400,000 to WARF upon execution of the WARF
License Agreement. Discovery is obligated to pay WARF a royalty on net sales
of ST-630 sold by it or its sublicensees in the licensed territories. In
addition, Discovery is obligated to pay WARF a percentage of its income from
sublicensees. The WARF License Agreement also provides for the making of the
following milestone and option payments:
 
    For the exclusive license to the Western hemisphere: $150,000 upon
  completion of Phase II studies in the United States; and $1 million upon
  NDA submission in the United States. For the option for an exclusive
  license to Belgium, France, Germany, Italy, the Netherlands, Switzerland
  and the United Kingdom: $200,000 upon exercise of Discovery's option and $1
  million upon the first submission of an NDA with any European country. For
  the option for an exclusive license for the remaining countries of the
  world (other than Argentina, Spain, Portugal, Korea and Japan): $500,000
  upon exercise of Discovery's option. For the option for an exclusive
  license for Argentina, $10,000; for Spain, $170,000; for Portugal, $50,000;
  and for Korea, $15,000, in each case upon exercise of Discovery's option.
  Each such option must be exercised no later than January 1, 2002.
 
    To maintain the license, Discovery is required to pay minimum royalties
  of $100,000 per year beginning in calendar year 2002. The WARF License
  Agreement shall remain in effect and royalties shall
 
                                      100

  be payable for a period of fifteen years from the date approval is received
  in the United States for the sale of ST-630, after which time Discovery
  shall have a fully paid license.
 
  So long as the WARF License Agreement remains in effect, WARF is prohibited
from granting a license to any other party (other than in Japan) with respect
to ST-630 or certain proprietary information relating thereto for any
indication, with the exception of WARF's existing license agreement with
Penederm, Inc.
 
  The ST-630 Patent will expire in July 2001, which Discovery anticipates will
be prior to receipt of any marketing approval for ST-630 in the United States.
The ST-630 Use Patent, which expires in 2014, is limited to claims relating to
a method of treating postmenopausal osteoporosis in humans having such disease
with an effective dosage of ST-630. These claims do not include claims
relating to the use of ST-630 to treat other metabolic bone disorders, such as
age-related osteoporosis (which occurs in men and women) and renal
osteodystrophy. At Discovery's request, WARF recently filed an application to
pursue additional claims relating to the use of ST-630 to treat other
metabolic bone diseases. However, there can be no assurance that any patent
containing such additional claims will issue in the United States or
elsewhere.
 
  Foreign patent applications corresponding to the ST-630 Patent and/or the
ST-630 Use Patent have also been filed in certain countries, and such
applications and any resulting patents are licensed to Discovery under the
WARF License Agreement. United States and foreign patents covering certain
processes relating to the manufacture of vitamin D analogs, which have been
nonexclusively licensed to Discovery under the WARF License Agreement, will
expire on various dates up to 2005.
 
UNCERTAINTY OF BIOTECHNOLOGY PATENTS
 
  The patent position of firms relying upon biotechnology is highly uncertain
and involves complex legal and factual questions. To date, there has emerged
no consistent policy regarding the breadth of claims allowed in biotechnology
patents or the degree of protection afforded under such patents. The patent
application and issuance process can be expected to take several years and
could entail considerable expense to Discovery. There can be no assurance that
patents will issue as a result of any applications filed or that the existing
patents or patents issued from existing applications will be sufficiently
broad to afford protection against competitors with similar technology. In
addition, there can be no assurance that such patents will not be challenged,
invalidated or circumvented, or that the rights granted thereunder will
provide competitive advantages to Discovery. The commercial success of
Discovery will also depend upon its avoidance of infringement of patents
issued to competitors. A United States patent application is maintained under
conditions of confidentiality while the application is pending, so Discovery
cannot determine the inventions being claimed in pending patent applications
filed by third parties. Litigation may be necessary to defend or enforce
Discovery's patent and license rights or to determine the scope and validity
of the proprietary rights of others. Defense and enforcement of patent claims
can be expensive and time consuming, even in those instances in which the
outcome is favorable to Discovery, and can result in the diversion of
substantial resources from Discovery's other activities. An adverse outcome
could subject Discovery to significant liabilities to third parties, require
Discovery to obtain licenses from third parties, or require Discovery to alter
its products or processes, or cease altogether any related research and
development activities or product sales, any of which may have a material
adverse effect on Discovery's business, financial condition and results of
operations.
 
  Tyloxapol, the active compound in SuperVent(TM) was the subject of an issued
U.S. composition of matter patent which expired in 1965. The patents and
patent applications licensed to Discovery differ from the expired patent,
inter alia, in that one patent application covers proprietary pharmaceutical
formulations containing high concentrations of tyloxapol and the other patents
and patent applications cover uses of tyloxapol to treat certain diseases.
Although Discovery believes that high concentration formulations of tyloxapol
will represent the most practical means to deliver the active compound, there
can be no assurance that any patent application covering this formulation will
issue or that the compound will not prove similarly effective in lower
concentrations which are not covered by any of Discovery's patent
applications.
 
                                      101

CONFIDENTIALITY; ASSIGNMENT OF INVENTIONS
 
  Discovery requires all employees to enter into confidentiality agreements
that prohibit the disclosure of confidential information to third parties and
require disclosure and assignment to Discovery of rights to their ideas,
developments, discoveries and inventions. In addition, Discovery seeks to
obtain such agreements from its consultants, advisors and research
collaborators; however, such agreements may not be possible where such persons
are employed by universities or other academic institutions that require
assignment of employee inventions to them. To the extent that consultants, key
employees, or other third parties apply technological information
independently developed by them or by others to any of the proposed projects
of Discovery, disputes may arise as to the proprietary rights to such
information which may not be resolved in favor of Discovery. In addition,
Discovery also relies on trade secrets and proprietary know-how, that it seeks
to protect in part by its confidentiality agreements with its employees,
consultants, advisors or others. There can be no assurance that these
agreements will not be breached, that Discovery would obtain adequate remedies
for any breach, or that such trade secrets or proprietary know-how will not
otherwise become known or be independently developed by competitors in such a
manner that Discovery has no legal recourse.
 
THIRD PARTY SUPPLIERS
 
  To be successful, Discovery's products must be manufactured in commercial
quantities under GMP requirements set by the FDA at acceptable costs. The FDA
periodically inspects manufacturing facilities in the United States in order
to assure compliance with applicable GMP requirements. Foreign manufacturers
also are inspected by the FDA if their drugs are marketed in the United
States. Failure of the foreign or domestic suppliers of Discovery's products
or failure of the manufacturers of Discovery's products to comply with GMP
regulations or other FDA regulatory requirements would have a material adverse
effect on Discovery's business, financial condition and results of operations.
Discovery does not have any manufacturing capacity of its own but instead
intends to rely on outside manufacturers to produce appropriate clinical grade
material for its use in clinical studies for certain of its products.
 
  The active compound in SuperVent(TM) is presently manufactured for several
third parties pursuant to GMP standards by an affiliate of Sanofi, a
multinational pharmaceutical company. Sanofi is the sole supplier of tyloxapol
with GMP standard manufacturing capabilities and there are few alternative
non-GMP approved sources of supply. Currently, Discovery purchases bulk
tyloxapol from Sanofi on an as-needed basis. Although Sanofi has sold a
quantity of tyloxapol sufficient for Discovery's proposed Phase I/II clinical
trial of SuperVent(TM), the Combined Company is not expected to have an
agreement with Sanofi to supply any additional material, either in connection
with a Phase III clinical trial or, following regulatory approval, for
marketing purposes. In addition, Discovery does not intend to enter into an
agreement for supply of the formulated drug containing tyloxapol unless it
plans to initiate a Phase III clinical trial of tyloxapol for the treatment of
CF. There can be no assurance that Discovery will be able to enter into a
supply agreement with Sanofi or a supplier of the formulated drug on terms
acceptable to Discovery, if at all. In such case, Discovery would be required
to seek alternate manufacturing sources capable of producing tyloxapol and the
formulated drug. There can be no assurance that Discovery will be able to
identify and contract with alternative manufacturers on terms acceptable to
it, if at all. Any interruption in the supply of tyloxapol would have a
material adverse effect on Discovery's business, financial condition and
results of operations.
 
  Tetrionics manufactures, formulates and supplies Discovery with GMP-grade
ST-630 for Discovery's investigational and commercial purposes on an as-needed
basis. Tetrionics presently manufactures and supplies ST-630 to Penederm, Inc.
in the United States for investigational topical use for the treatment of
psoriasis. It is anticipated that the Combined Company will have no long-term
agreement with Tetronics or any other suppliers for ST-630. Any interruption
of the Combined Company's supply of ST-630 could substantially delay the
Combined Company's development efforts with respect to ST-630 and could have a
material adverse effect on the Combined Company.
 
                                      102

MARKETING AND SALES
 
  It is Discovery's long-term goal to market SuperVent(TM) for CF and possibly
certain of its other products through a direct sales force (or, in the case of
CF, possibly through the distribution capabilities of the Cystic Fibrosis
Foundation), if and when any necessary regulatory approvals are obtained.
Discovery currently has no marketing and sales experience and no marketing or
sales personnel. Unless a sales force is established, Discovery will be
dependent on corporate partners or other entities for the marketing and
selling of its products. There can be no assurance that Discovery will be able
to enter into any satisfactory arrangements for the marketing and selling of
its products. The inability of Discovery to enter into such third party
distribution, marketing and selling arrangements for its anticipated products
could have a material adverse effect on Discovery's business, financial
condition and results of operations.
 
EMPLOYEES
 
  Discovery utilizes a product development strategy that involves contracting
out research, development and manufacturing functions to third parties in
order to minimize the expense and overhead associated with full-time
employees. Consistent with this strategy, Discovery has only nine employees.
James S. Kuo, M.D., joined Discovery in April 1996 as President, Chief
Executive Officer and a Director. David R. Crockford joined Discovery in
November 1996 as Vice President of Regulatory Affairs. Evan Myrianthopoulos
joined Discovery in June 1996 and has served as Chief Operating Officer,
Secretary and a Director since that time. Mr. Myrianthopoulos became a full-
time employee of Discovery as of January 1, 1997. During 1996,
Mr. Myrianthopoulos devoted only a portion of his time to the business of
Discovery. Steve Birnbaum joined Discovery in November 1996 as the Project
Manager for the ST-630 program. Discovery employs three other full-time
employees and two employees who devote only a portion of their time to the
business of Discovery: Steve H. Kanzer, C.P.A., Esq., Discovery's Chairman,
and Kenneth Johnson, Discovery's Director of Business Development. ATI has
only eight employees. Robert J. Capetola, Ph. D., joined ATI in October 1996
as President, Chief Executive Officer and Chairman of the Board. Thomas E.
Wiswell, M.D. joined ATI as Vice President of Clinical Research in September
1996. Harry G. Brittain, Ph.D., joined ATI as Vice President of Pharmaceutical
and Chemical Development in November 1996. Laurence B. Katz, Ph.D., joined ATI
as Vice President of Project Management and Clinical Administration in
November 1996. Christopher J. Schaber joined ATI as Vice President of
Regulatory Affairs and Quality Assurance in November 1996. ATI employs three
other full-time employees, including Huei Tsai, Ph.D., who joined ATI as Vice
President of Biometrics in February 1997, and Lisa Mastroianni, who joined ATI
as Director of Clinical Research in February 1997. See "Risk Factors--
Dependence on Key Personnel and Consultants."
 
FACILITIES
 
  Discovery currently has its executive offices at 509 Madison Avenue, 14th
Floor, New York, New York 10022. Discovery's telephone number is (212) 223-
9504 and its facsimile number is (212) 688-7978. Discovery's internet address
is www.discoverylabs.com.
 
  ATI currently has its executive offices at 3359 Durham Road, Doylestown, PA
18901. ATI's telephone number is (215) 794-3064 and its facsimile number is
(215) 794-3239.
 
  Discovery presently has no research or manufacturing facilities. Discovery
intends to rely upon third party manufacturers to produce pharmaceutical
material and third party contract research organizations to conduct research
and clinical testing with regard to its proposed products.
 
LEGAL PROCEEDINGS
 
  Discovery is not aware of any pending or threatened legal actions.
 
                                      103

                                 LEGAL MATTERS
 
  The validity of the Ansan Common Stock issuable pursuant to the Merger, the
federal income tax consequences of the Merger and certain other legal matters
relating thereto will be passed upon for Ansan by Heller Ehrman White &
McAuliffe, Palo Alto, California. Roberts, Sheridan & Kotel, New York, New
York, is acting as counsel for Discovery in connection with the federal income
tax consequences of the Merger and certain legal matters relating to the
Merger and the transactions contemplated thereby.
 
                                    EXPERTS
 
  The financial statements of Ansan as of December 31, 1995 and 1996 and for
the years then ended appearing in this Prospectus/Proxy Statement have been
audited by Ernst & Young LLP, independent auditors, as set forth in their
report thereon appearing elsewhere herein, and are included in reliance upon
such report given, upon the authority of such firm as experts in accounting
and auditing.
 
  The financial statements of Discovery as of December 31, 1996 and for the
two years then ended and for the period from May 18, 1993 (inception) to
December 31, 1996 appearing in this Prospectus/Proxy Statement have been
audited by Richard A. Eisner & Company, LLP, independent auditors, as set
forth in their report thereon appearing elsewhere herein, and are included in
reliance upon such report given, upon the authority of such firm as experts in
accounting and auditing.
 
                                      104

                          DESCRIPTION OF ANSAN STOCK
 
  As of the date of this Prospectus/ Proxy Statement, the authorized capital
stock of Ansan consists of 20,000,000 shares of Ansan Common Stock and
5,000,000 shares of Preferred Stock.
 
COMMON STOCK
 
  As of the July 31, 1997, there were 2,851,954 shares of Ansan Common Stock
outstanding held of record by 12 stockholders. Holders of shares of Ansan
Common Stock are entitled to one vote per share on all matters to be voted on
by stockholders. Subject to preferences that may be applicable to any
outstanding preferred stock, holders of Ansan Common Stock are entitled to
receive ratably such dividends as may be declared by the Board of Directors in
its discretion from funds legally available therefor. In the event of a
liquidation, dissolution, or winding up of Ansan, holders of Ansan Common
Stock are entitled to share ratably in all assets remaining after payment of
liabilities and the liquidation preference of any outstanding preferred stock.
Holders of Ansan Common Stock have no preemptive rights and have no rights to
convert their Ansan Common Stock into any other securities. The outstanding
shares of Ansan Common Stock are fully paid and nonassessable.
 
PREFERRED STOCK
 
  The Board of Directors has the authority to issue up to 5,000,000 shares of
preferred stock in one or more series and to fix the rights, preferences,
privileges and restrictions thereof, including dividend rights, conversion
rights, voting rights, terms of redemption, liquidation preferences and the
number of shares constituting any series or the designation of such series,
without any further vote or action by the Ansan stockholders. The issuance of
preferred stock may have the effect of delaying, deferring or preventing a
change in control of Ansan or making removal of management more difficult
without further action by the stockholders and could adversely affect the
rights and powers, including voting rights, of the holders of Ansan Common
Stock. This could have the effect of decreasing the market price of the Ansan
Common Stock.
 
  At present Ansan has filed a Certificate of Designation creating a series of
Preferred Stock designated as Series A Preferred Stock. Of the Ansan Series A
Preferred Stock, 13,000 shares are currently issued and outstanding. As of the
date hereof, all of such shares of Series A Preferred Stock are legally and
beneficially owned by Discovery pursuant to the Series A Purchase Agreement.
The Merger Agreement provides that all Ansan Stock (including all shares of
Series A Preferred Stock) owned by Discovery prior to the Effective Time shall
be cancelled as of such date.
 
TRANSFER AGENT AND REGISTRAR
 
  Continental Stock Trust & Transfer Company acts as the transfer agent and
registrar for the Ansan Common Stock.
 
                       COMPARISON OF STOCKHOLDER RIGHTS
 
 Size of the Board of Directors
 
  The Discovery Bylaws provide the Discovery Board with the authority to
determine and set the exact number of directors. The Ansan Bylaws provide the
Ansan Board with the authority to determine and set the exact number of
directors. Pursuant to the Merger Proposal, the number of directors of Ansan
subsequent to the Merger shall consist of ten members as specified in this
Prospectus/Proxy Statement. See "Terms of the Merger--Management After the
Merger".
 
 Voting
 
  Neither the current Discovery Certificate of Incorporation (the "Discovery
Certificate") nor the current Ansan Certificate of Incorporation (the "Ansan
Certificate") provide for cumulative voting. The Discovery
 
                                      105

Certificate provides that each share of Discovery Common Stock, on an as-
converted basis, shall have one vote therefor. Additionally, all shares of
Discovery Stock shall vote together as a single class unless a vote by class
is provided by the DGCL. The Ansan Certificate provides that each share of
Ansan Common Stock, on an as-converted basis, shall have one vote therefor.
Additionally, all shares of Ansan Stock shall vote together as a single class
unless a vote by class is provided by the DGCL.
 
 Power to Call Special Stockholder Meetings
 
  Under the DGCL, a special meeting of stockholders may be called by the board
of directors or by any other person authorized to do so in the Certificate of
Incorporation or the Bylaws. Pursuant to the Discovery Bylaws, a special
meeting of the stockholders may be called by the directors or any officer
authorized by the directors to so act. Pursuant to the Ansan Bylaws, a special
meeting of the stockholders may be called by the board of directors, the
Chairman of the Board or the President. The board of directors shall call a
special meeting of the stockholders when the holders of at least 20% of the
outstanding stock of Ansan so request in writing provided that such request in
writing is accompanied by a notice stating the object of such meeting.
 
 Removal of Directors
 
  The Discovery Bylaws provide that, except as provided by the DGCL, any
director or the entire Board of Directors may be removed, with or without
cause, by the holders of a majority of the shares then entitled to vote at an
election of directors. The Ansan Bylaws provide that, except as provided by
the DGCL, any director or the entire Board of Directors may be removed, with
or without cause, by the holders of a majority of the votes of the issued and
outstanding shares at a meeting called for that purpose or by a majority vote
of the Board of Directors at a meeting called for that purpose.
 
 Filling Vacancies on the Board of Directors
 
  The Discovery Bylaws provide that newly created directorships and any
vacancies in the Board of Directors, including unfilled vacancies resulting
from the removal of directors for cause or without cause, may be filled by the
vote of a majority of the remaining directors then in office, although less
than a quorum, or by the sole remaining director. The Ansan Bylaws provide
that vacancies in the Board of Directors, including newly created
directorships, may be filled by the majority vote of the directors then in
office, including those who have resigned, such vote to take effect when such
resignation or resignations shall become effective.
 
 Indemnification and Limitation of Liability
 
  The Discovery Certificate contains a provision limiting the personal
liability of directors to the fullest extent permitted by the DGCL. The
Discovery Certificate also contains a provision indemnifying any and all
persons that it has the power to indemnify pursuant to the DGCL to the fullest
extent provided by the DGCL. Such indemnification is not to be deemed
exclusive of any other rights to which those indemnified may be entitled under
any bylaw, agreement, vote of stockholders or disinterested directors or
otherwise, both as to actions in their official capacity and as to action in
another capacity while holding such office and shall continue subsequent to
such person ceasing to hold such office.
 
  The Ansan Certificate contains a provision limiting the personal liability
of a director for monetary damages for breach of fiduciary duty as a director
to the corporation or any stockholder to the fullest extent provided by the
DGCL. The Ansan Bylaws contain a provision indemnifying all persons that it
shall have the power to indemnify to the fullest extent permitted by the DGCL
in respect of their having been officers or directors of Ansan, any subsidiary
of Ansan or of any other corporation of which they acted as officer or
director at the request of Ansan.
 
  Under the DGCL, an indemnity provision may not eliminate director monetary
liability for : (a) breaches of the director's duty of loyalty to the
corporation or its stockholders; (b) acts or omissions not in good faith or
 
                                      106

involving intentional misconduct or knowing violations of law; (c) the payment
of unlawful dividends or unlawful stock repurchases or redemptions; or (d)
transactions in which the director received an improper personal benefit.
Limitation of liability provisions also may not limit a director's liability
for violation of, or otherwise relieve a company or its directors from, the
necessity of complying with, Federal or state securities laws, or affect the
availability of non-monetary remedies such as injunctive relief or rescission.
 
 Stockholder Action by Written Consent
 
  Both the Discovery Bylaws and the Ansan Bylaws provide that any action
required or permitted to be taken at any annual or special meeting of the
stockholders, may be taken without meeting and without either prior notice or
a vote, if a consent in writing setting forth the action so taken shall be
signed by stockholders representing the minimum number of votes that would be
necessary to authorize or take such action at an annual or special meeting of
the stockholders, as the case may be. The Discovery Bylaws require that prompt
notice of the taking of any action authorized by written consent, but by less
than unanimous written consent of all stockholders, shall be provided to those
stockholders who have not so consented in writing.
 
 Interested Director Transactions
 
  The Ansan Bylaws provide that no contract or other transaction between Ansan
and any other corporation shall be affected and invalidated by the fact that
any one or more of the directors of Ansan is or are interested in or is a
director or officer of such other corporation and any Ansan director or
directors may be interested in, be a party to or otherwise connected with, any
contract or transaction of Ansan or in which Ansan is itself interested. This
provision also relieves Ansan's directors from any liability that otherwise
might exist from so contracting with Ansan. The Discovery Bylaws contain no
similar provision.
 
                                      107

          ANSAN PHARMACEUTICALS, INC. --  AUDITED FINANCIAL STATEMENTS
           AT DECEMBER 31, 1995 AND 1996 AND FOR THE YEARS THEN ENDED
                     AND FOR THE PERIOD FROM INCORPORATION
                    (NOVEMBER 6, 1992) TO DECEMBER 31, 1997
 
                         INDEX TO FINANCIAL STATEMENTS

                                                                            PAGE
                                                                            ----
                                                                         
Report of Ernst & Young LLP, Independent Auditors..........................  F-2
Financial Statements
  Balance Sheets...........................................................  F-3
  Statements of Operations.................................................  F-4
  Statement of Stockholders' Equity (Net Capital Deficiency)...............  F-5
  Statements of Cash Flows.................................................  F-7
  Notes to Financial Statements............................................  F-8
 
    ANSAN PHARMACEUTICALS, INC. --  UNAUDITED CONDENSED FINANCIAL STATEMENTS
            AT JUNE 30, 1997 AND FOR THE THREE AND SIX MONTH PERIODS
       ENDED JUNE 30, 1996 AND 1997 AND FOR THE PERIOD FROM INCORPORATION
                      (NOVEMBER 6, 1992) TO JUNE 30, 1997
 
Financial Statements
  Condensed Balance Sheet.................................................. F-17
  Condensed Statements of Operations....................................... F-18
  Condensed Statements of Cash Flows....................................... F-19
  Notes to Condensed Financial Statements.................................. F-20

    DISCOVERY LABORATORIES, INC. AND SUBSIDIARY  --  CONSOLIDATED FINANCIAL
                                   STATEMENTS
              AT DECEMBER 31, 1996 AND JUNE 30, 1997 (UNAUDITED),
    FOR THE YEARS ENDED DECEMBER 31, 1995 AND 1996, FOR THE SIX MONTHS ENDED
    JUNE 30, 1997 AND 1996 (UNAUDITED), AND FOR THE PERIOD FROM MAY 18, 1993
                                  (INCEPTION)
               TO DECEMBER 31, 1996 AND JUNE 30, 1997 (UNAUDITED)
 
  Report of Independent Auditors........................................... F-23
  Consolidated Balance Sheets.............................................. F-24
  Consolidated Statements of Operations.................................... F-25
  Consolidated Statements of Changes in Stockholders' Equity............... F-26
  Consolidated Statements of Cash Flows.................................... F-27
  Notes to Consolidated Financial Statements............................... F-28

                                      F-1

               REPORT OF ERNST & YOUNG LLP, INDEPENDENT AUDITORS
 
The Board of Directors and Stockholders
Ansan Pharmaceuticals, Inc.
 
  We have audited the accompanying balance sheets of Ansan Pharmaceuticals,
Inc. (a development stage company) as of December 31, 1995 and 1996, and the
related statements of operations, stockholders' equity (net capital
deficiency), and cash flows for the years then ended and for the period from
incorporation (November 6, 1992) to December 31, 1996. These financial
statements are the responsibility of the Company's management. Our
responsibility is to express an opinion on these financial statements based on
our audits.
 
  We conducted our audits in accordance with generally accepted auditing
standards. Those standards require that we plan and perform the audit to
obtain reasonable assurance about whether the financial statements are free of
material misstatement. An audit includes examining, on a test basis, evidence
supporting the amounts and disclosures in the financial statements. An audit
also includes assessing the accounting principles used and significant
estimates made by management, as well as evaluating the overall financial
statement presentation. We believe that our audits provide a reasonable basis
for our opinion.
 
  In our opinion, the financial statements referred to above present fairly,
in all material respects, the financial position of Ansan Pharmaceuticals,
Inc. (a development stage company) at December 31, 1995 and 1996, and the
results of its operations and its cash flows for the years then ended and for
the period from incorporation (November 6, 1992) to December 31, 1996 in
conformity with generally accepted accounting principles.
 
  The accompanying financial statements have been prepared assuming that Ansan
Pharmaceuticals will continue as a going concern. As more fully described in
Note 1, the Company has incurred recurring operating losses and expects such
losses to continue for at least the next several years. These conditions raise
substantial doubt about the Company's ability to continue as a going concern.
The financial statements do not include any adjustments to reflect the
possible future effects on the recoverability and classification of assets or
the amounts and classification of liabilities that may result from the outcome
of this uncertainty.
 
                                          Ernst & Young LLP
 
Palo Alto, California
February 21, 1997 except for Note 8
 as to which the date is July 16, 1997
 
                                      F-2

                          ANSAN PHARMACEUTICALS, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
                                 BALANCE SHEETS

                                                            DECEMBER 31,
                                                        ----------------------
                                                           1995        1996
                                                        ----------  ----------
                                                              
                        ASSETS
Current assets:
  Cash and cash equivalents............................ $   45,202  $  245,778
  Short-term investments...............................  3,809,110   1,500,000
  Prepaid expenses and other current assets............    108,089      83,760
                                                        ----------  ----------
    Total current assets...............................  3,962,401   1,829,538
Furniture and equipment, net...........................     18,244      93,936
                                                        ----------  ----------
                                                        $3,980,645  $1,923,474
                                                        ==========  ==========
         LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities
  Accounts payable..................................... $   80,276  $   91,041
  Payable to Titan Pharmaceuticals, Inc. ..............     57,791     117,881
  Accrued sponsored research...........................     32,890      36,330
  Accrued legal fees...................................     50,000      26,327
  Other accrued liabilities............................    117,006      62,457
                                                        ----------  ----------
    Total current liabilities .........................    337,963     334,036
Commitments
Stockholders' Equity
  Common stock, $0.001 par value per share; 20,000,000
   shares authorized; 2,768,164 and 2,845,108 shares
   issued and outstanding at December 31, 1995 and
   1996, respectively.................................. 10,678,061  10,850,017
  Deferred compensation................................   (236,118)   (180,561)
  Deficit accumulated during the development stage..... (6,799,261) (9,080,018)
                                                        ----------  ----------
    Total stockholders' equity.........................  3,642,682   1,589,438
                                                        ----------  ----------
                                                        $3,980,645  $1,923,474
                                                        ==========  ==========

 
                            See accompanying notes.
 
                                      F-3

                          ANSAN PHARMACEUTICALS, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
                            STATEMENTS OF OPERATIONS

                                                                   PERIOD FROM
                                                                  INCORPORATION
                                                                  (NOVEMBER 6,
                                        YEAR ENDED DECEMBER 31,     1992) TO
                                        ------------------------  DECEMBER 31,
                                           1995         1996          1996
                                        -----------  -----------  -------------
                                                         
Costs and expenses:
  Research and development(1).......... $ 1,410,762  $ 1,181,089   $ 5,583,853
  Sponsored research and development
   and license fees--stockholder.......      10,000          --        396,689
  General and administrative(1)........   1,047,795    1,257,365     2,914,197
                                        -----------  -----------   -----------
    Total costs and expenses and loss
     from operations...................  (2,468,557)  (2,438,454)   (8,894,739)
Other income (expense):
  Interest income......................      77,891      157,697       249,870
  Interest expense.....................    (430,740)         --       (435,149)
                                        -----------  -----------   -----------
    Other income (expense)--net........    (352,849)     157,697      (185,279)
                                        -----------  -----------   -----------
      Net loss......................... $(2,821,406) $(2,280,757)  $(9,080,018)
                                        ===========  ===========   ===========
Pro forma net loss per share........... $     (1.93)
                                        ===========
Shares used in computing pro forma net
 loss per share........................   1,464,713
                                        ===========
Net loss per share.....................              $     (0.94)
                                                     ===========
Shares used in computing net loss per
 share.................................                2,431,447
                                                     ===========

- --------
(1) See Note 6 for description of related party transactions.

                            See accompanying notes.
 
                                      F-4

                          ANSAN PHARMACEUTICALS, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
           STATEMENT OF STOCKHOLDERS' EQUITY (NET CAPITAL DEFICIENCY)

                                                                                                 DEFICIT
                                                                                     AMOUNT    ACCUMULATED  STOCKHOLDERS'
                          PREFERRED STOCK          COMMON STOCK                    RECEIVABLE  DURING THE    EQUITY (NET
                        ---------------------  ---------------------   DEFERRED       FROM     DEVELOPMENT     CAPITAL
                         SHARES     AMOUNT      SHARES     AMOUNT    COMPENSATION STOCKHOLDERS    STAGE      DEFICIENCY)
                        --------  -----------  --------- ----------- ------------ ------------ -----------  -------------
                                                                                    
Issuance of common
 stock to parent for
 amount receivable in
 November 1992 at
 $0.0058 per share....       --   $       --     327,446 $     1,900  $     --      $(1,900)   $       --    $       --
Issuance of common
 stock for amount
 receivable in January
 1993 at $0.0058 per
 share................       --           --      17,234         100        --         (100)           --            --
Forgiveness of note
 payable to related
 party................       --           --         --       30,000        --          --             --         30,000
Net loss, inception
 through December 31,
 1993.................       --           --         --          --         --          --        (849,963)     (849,963)
                        --------  -----------  --------- -----------  ---------     -------    -----------   -----------
Balances at December
 31, 1993.............       --           --     344,680      32,000        --       (2,000)      (849,963)     (819,963)
Cash received in April
 1994 for settlement
 of stockholder
 receivable...........       --           --         --          --         --        1,900            --          1,900
Issuance of common
 stock in May 1994 at
 $0.46 per share in
 exchange for amount
 receivable and
 services.............       --           --      43,276      20,089        --         (105)           --         19,984
Issuance of Series A
 preferred stock to
 parent for cash and
 conversion of debt in
 May 1994 for $4.58
 per share............   532,651    2,441,656        --          --         --          --             --      2,441,656
Net loss--Year ended
 December 31, 1994....       --           --         --          --         --          --      (3,127,892)   (3,127,892)
                        --------  -----------  --------- -----------  ---------     -------    -----------   -----------
Balances at December
 31, 1994.............   532,651  $ 2,441,656    387,956 $    52,089  $     --      $  (205)   $(3,977,855)  $(1,484,315)
Issuance of warrants
 associated with
 bridge financing in
 June of 1995.........       --           --         --      400,000        --          --             --        400,000
Deferred compensation.       --           --         --      277,784   (277,784)        --             --            --
Amortization of
 deferred
 compensation.........       --           --         --          --      41,666         --             --         41,666
Issuance of common
 stock to parent upon
 conversion of debt in
 August 1995 for $4.40
 per share............       --           --     352,557   1,551,252        --          --             --      1,551,252
Conversion of Series A
 preferred stock to
 common stock in
 August 1995..........  (532,651)  (2,441,656)   532,651   2,441,656        --          --             --            --
Issuance of common
 stock and warrants at
 $5.00 per unit in
 initial public
 offering in August
 1995 net of issuance
 costs of $1,393,100..       --           --   1,300,000   5,106,900        --          --             --      5,106,900
Issuance of common
 stock and warrants at
 $5.00 per unit from
 exercises of
 underwriter's over-
 allotment option in
 September 1995.......       --           --     195,000     848,250        --          --             --        848,250
Cash received from
 underwriter purchase
 of 130,000 common
 stock options at
 $0.001 per share.....       --           --         --          130        --          --             --            130
Forgiveness of
 stockholder
 receivable in
 December 1995........       --           --         --          --         --          205            --            205
Net loss--Year ended
 December 31, 1995....       --           --         --          --         --          --      (2,821,406)   (2,821,406)
                        --------  -----------  --------- -----------  ---------     -------    -----------   -----------
Balances at December
 31, 1995.............       --           --   2,768,164  10,678,061   (236,118)        --      (6,799,261)    3,642,682
                        ========  ===========  ========= ===========  =========     =======    ===========   ===========

                            See accompanying notes.
 
                                      F-5

                          ANSAN PHARMACEUTICALS, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
           STATEMENT OF STOCKHOLDERS' EQUITY (NET CAPITAL DEFICIENCY)

                                                                                                DEFICIT    STOCKHOLDERS'
                                                                                    AMOUNT    ACCUMULATED     EQUITY
                          PREFERRED STOCK         COMMON STOCK                    RECEIVABLE  DURING THE       (NET
                          -----------------   ---------------------   DEFERRED       FROM     DEVELOPMENT     CAPITAL
                          SHARES    AMOUNT     SHARES     AMOUNT    COMPENSATION STOCKHOLDERS    STAGE      DEFICIENCY)
                          -------   -------   --------- ----------- ------------ ------------ -----------  -------------
                                                                                   
Issuance of common stock
 to employee in
 September 1996 as
 compensation...........        --   $    --     40,000 $   155,000  $     --        $--      $       --    $   155,000
Issuance of shares of
 common stock for cash
 upon exercise of stock
 option grants at $0.06
 to $0.58 per share in
 July through December
 1996...................        --        --     36,944      16,956        --         --              --         16,956
Amortization of deferred
 compensation...........        --        --        --          --      55,557        --              --         55,557
Net loss--Year ended
 December 31, 1996......        --        --        --          --         --         --       (2,280,757)   (2,280,757)
                           -------   -------  --------- -----------  ---------       ---      -----------   -----------
Balances at December 31,
 1996...................        --   $    --  2,845,108 $10,850,017  $(180,561)      $--      $(9,080,018)  $ 1,589,438
                           =======   =======  ========= ===========  =========       ===      ===========   ===========

 
                            See accompanying notes.
 
                                      F-6

                          ANSAN PHARMACEUTICALS, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
                            STATEMENTS OF CASH FLOWS

                                                                   PERIOD FROM
                                                                  INCORPORATION
                                              YEAR ENDED          (NOVEMBER 6,
                                             DECEMBER 31,            1992 TO
                                        ------------------------  DECEMBER 31,
                                           1995         1996          1996
                                        -----------  -----------  -------------
                                                         
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss..............................  $(2,821,406) $(2,280,757)  $(9,080,018)
Adjustments to reconcile net loss to
 net cash used in operating
 activities:
  Depreciation expense................        1,659       22,324        23,983
  Amortization of debt account........      400,000          --        400,000
  Amortization of deferred
   compensation.......................       41,666       55,557        97,223
  Forgiveness of stockholder
   receivable.........................          205          --            205
  Issuance of common stock in exchange
   for consulting services............          --           --         19,984
  Grant of common stock to employee...          --       155,000       155,000
  Changes in operating assets and
   liabilities:
    Prepaid expenses and other current
     assets...........................     (108,089)      24,329       (83,760)
    Accounts payable..................      (18,630)      10,765        91,041
    Accrued sponsored research........     (143,110)       3,440        36,330
    Accrued legal fees................       50,000      (23,673)       26,327
    Other accrued liabilities.........      103,853      (54,549)       62,457
                                        -----------  -----------   -----------
Net cash provided by (used in)
 investing activities.................   (2,493,852)  (2,087,564)   (8,251,228)
                                        -----------  -----------   -----------
CASH FLOWS FROM INVESTING ACTIVITIES
  Purchase of furniture and equipment.      (19,903)     (98,016)     (117,919)
  Purchase of short-term investments..   (3,809,110)  (4,940,890)   (8,750,000)
  Sales of short-term investments.....          --     7,250,000     7,250,000
                                        -----------  -----------   -----------
Net cash provided by (used in)
 investing activities.................   (3,829,013)   2,211,094    (1,617,919)
                                        -----------  -----------   -----------
CASH FLOWS FROM FINANCING ACTIVITIES
  Proceeds from issuance of Series A
   preferred stock....................          --           --        992,592
  Proceeds from issuance of common
   stock..............................    5,995,280       16,956     5,972,236
  Proceeds from related party notes...          --           --        220,000
  Payment on related party notes......          --           --       (190,000)
  Issuance of notes payable...........    1,025,000          --      1,025,000
  Repayment of note payable...........   (1,425,000)         --     (1,425,000)
  Issuance of warrants to purchase
   common stock.......................      400,000          --        400,000
  Proceeds from stockholder
   receivable.........................          --           --          1,900
  Payable to Tital Pharmaceuticals,
   Inc. ..............................      316,083       60,090     3,118,197
                                        -----------  -----------   -----------
Net cash provided by financing
 activities...........................    6,271,363       77,046    10,114,925
                                        -----------  -----------   -----------
Net increase (decrease) in cash and
 cash equivalents.....................      (51,502)     200,576       245,778
Cash and cash equivalents, beginning
 of period............................       96,704       45,202           --
                                        -----------  -----------   -----------
Cash and cash equivalents, end of
 period...............................  $    45,202  $   245,778       245,778
                                        ===========  ===========   ===========
Supplemental cash flow disclosure
Forgiveness of note payable to related
 party................................  $       --   $       --    $    30,000
                                        ===========  ===========   ===========
Interest paid on related party notes..  $       --   $       --    $     4,409
                                        ===========  ===========   ===========
Conversion of payable to Titan into
 Series A preferred stock.............  $       --   $       --    $ 1,449,064
                                        ===========  ===========   ===========
Interest paid on bridge notes.........  $    29,694  $       --    $    29,694
                                        ===========  ===========   ===========
Conversion of payable to Titan into
 common stock.........................  $ 1,551,252  $       --    $ 1,551,252
                                        ===========  ===========   ===========

                            See accompanying notes.
 
                                      F-7

                          ANSAN PHARMACEUTICALS, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
                         NOTES TO FINANCIAL STATEMENTS
 
1. ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
 
 The Company
 
  Ansan Pharmaceuticals, Inc. ("Ansan") was incorporated in the State of
Delaware on November 6, 1992 to engage in the development of analogs of
butyric acid for the treatment of cancer, blood disorders and other serious
diseases.
 
 Relationship with Titan Pharmaceuticals, Inc.
 
  Titan, a biopharmaceutical company engaged, through the operations of its
subsidiaries and affiliates, in the development of new proprietary therapeutic
products for use in the fields of cancer, immunology, viral diseases, and
disorders of the central nervous system, was Ansan's parent until Ansan's
initial public offering (the "Offering") in August 1995 (see Note 3).
Immediately subsequent to the Offering, Titan's interest was reduced to a 44%.
Through December 31, 1996, Ansan contracted with Titan for facilities and
equipment, and certain administrative, financial, regulatory, business
development and human resource services. Titan has previously supplied working
capital financing to Ansan and may in the future provide such financing. At
December 31, 1996, Titan owned approximately 43% of Ansan. Certain members of
Titan's management and/or Board of Directors are also members of Ansan's Board
of Directors.
 
 Basis of Presentation
 
  Ansan's activities since incorporation have primarily consisted of
recruiting personnel, conducting research and development, preclinical and
clinical studies, performing business and financial planning and raising
capital. Accordingly, Ansan is considered to be in the development stage, and
expects to incur increasing losses and require additional financial resources
to achieve commercialization of its products.
 
  Ansan is engaged in a number of long-term development projects which involve
experimental technologies. Ansan has incurred losses since inception of $9.1
million and expects such losses to continue for at least the next several
years. The projects may require substantial expenditures and take a number of
years to develop prior to commercialization. Therefore, Ansan will need to
obtain additional funds to continue its research and development activities,
fund operating expenses, pursue regulatory approval, and build production,
sales, and marketing activities, as necessary. Sources of capital may include
the issuance of equity or debt securities to Titan or others (see Note 8), and
collaborative agreements. Management believes sufficient capital will be
available to achieve planned business objectives through at least 1997.
 
  The accompanying financial statements have been prepared assuming that Ansan
will continue as a going concern; however, the above conditions raise
substantial doubt about Ansan's ability to continue as a going concern.
Management recognizes the need for the infusion of cash during 1997 and 1998
and is actively pursuing various options including additional strategic
relationships and securing additional debt or equity financing. If Ansan is
unable to obtain the necessary cash, other more substantial restructuring
options may be necessary, which would have a material adverse effect on
Ansan's business, results of operations and prospects. The financial
statements do not include any adjustments to reflect the possible future
effects on the recoverability and classification of assets or the amounts and
classification of liabilities that may result from the outcome of this
uncertainty.
 
                                      F-8

                          ANSAN PHARMACEUTICALS, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
                  NOTES TO FINANCIAL STATEMENTS--(CONTINUED)

  In May 1995, the board of directors and stockholders of Ansan authorized a
0.1723399-for-one reverse stock split. Prior to the Offering, each share of
Series A preferred stock and common stock were split into 0.1723399 shares of
preferred stock and common stock, respectively. The accompanying financial
statements are adjusted to reflect the stock split on a retroactive basis.
 
 Use of Estimates
 
  The preparation of the financial statements in accordance with generally
accepted accounting principles requires that management make estimates and
assumptions that affect the amounts reported in the financial statements and
accompanying notes. Actual results may differ from those estimates.
 
 Cash, Cash Equivalents and Short-term Investments
 
  Ansan considers all highly liquid investments purchased with an original
maturity of 90 days or less to be cash equivalents. Cash equivalents included
$11,808 in money market funds at December 31, 1996.
 
  At December 31, 1995 and 1996, Ansan had $3,809,000 and $1,500,000,
respectively, of auction rate preferred stock (preferred stock in money market
mutual funds), classified as "available for sale." These amounts are stated at
cost which approximates estimated fair value. Ansan has not realized any gains
or losses on its investment.
 
 Furniture and Equipment
 
  Furniture and equipment is stated at cost and is depreciated using the
straight-line method over the estimated useful lives of the assets ranging
from three to five years. Leasehold improvements are amortized over the
remaining period of the lease.
 
 Stock-Based Compensation
 
  In accordance with the provisions of Statement of Financial Accounting
Standards No. 123, "Accounting for Stock-Based Compensation" ("SFAS 123"),
Ansan has elected to follow Accounting Principles Board Opinion No. 25,
"Accounting for Stock Issued to Employees" ("APB 25") and related
interpretations and to adopt the "disclosure only" alternative described in
SFAS 123 in accounting for its employee stock option plans. Under APB 25, if
the exercise price of Ansan's employee stock options equals or exceeds the
fair value of the underlying stock on the date of grant, no compensation
expense is recognized.
 
 Sponsored Research
 
  Research and development expenses under sponsored research arrangements are
recognized as the related services are performed, generally ratably over the
period of service. Payments for license fees are expensed when paid.
 
 Net Loss Per Share
 
  Net loss per share is computed using the weighted average number of common
shares outstanding. Common equivalent shares are excluded from the computation
as their effect is antidilutive, except that, pursuant to the Securities and
Exchange Commission ("SEC") Staff Accounting Bulletins, common equivalent
shares (stock options, warrants and preferred stock) issued during the period
commencing 12 months prior to March 31, 1995 at prices below the public
offering price have been included in the calculation as if they were
outstanding for all
 
                                      F-9

                          ANSAN PHARMACEUTICALS, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
                  NOTES TO FINANCIAL STATEMENTS--(CONTINUED)
 
periods presented (using the treasury stock method for stock options and the
if-converted method for the assumed conversion of the payable to Titan as of
March 31, 1995). However, shares to be held in escrow are not treated as
outstanding for any period (see Note 5.) Net loss per share calculated on this
basis for the year ended December 31, 1995 was $2.28.
 
  Pro forma net loss per share has been computed as described above and also
gives effect, pursuant to SEC policy, to common equivalent shares from
convertible preferred stock issued more than 12 months prior to the IPO that
automatically converted upon completion of Ansan's IPO (using the if-converted
method) from the original date of issuance.
 
2. FURNITURE AND EQUIPMENT
 
  Furniture and equipment consists of the following at December 31:

                                                               1995      1996
                                                              -------  --------
                                                                 
     Furniture and office equipment.......................... $11,521  $ 57,834
     Leasehold improvements..................................     --     19,817
     Computer equipment......................................   8,382    40,268
                                                              -------  --------
                                                               19,903   117,919
     Less accumulated depreciation and amortization..........  (1,659)  (23,983)
                                                              -------  --------
     Furniture and equipment, net............................ $18,244  $ 93,936
                                                              =======  ========

  Depreciation expense was $1,659 and $22,323 for the years ended December 31,
1995 and 1996, respectively.
 
3. SPONSORED RESEARCH AND LICENSE AGREEMENTS
 
  In July 1994, Ansan entered into a research agreement with a university.
Under the terms of the agreement, Ansan agreed to fund research of $105,700
through December 31, 1994. The agreement was extended six months beyond the
original term to allow for completion of the scope of the research program.
During the year ended December 31, 1995, Ansan incurred sponsored research
expenses of $62,000 related to this agreement.
 
  In 1992, Ansan entered into research and license agreements with Bar-Ilan
Research and Development Company, Ltd. ("Bar-Ilan"), an entity located in
Israel. The research agreement expired during 1994. Pursuant to the license
agreement, Ansan receives certain exclusive worldwide licenses to inventions
and confidential information related to the research program in exchange for
the research funding and specified royalties on future sales and/or
sublicensing arrangements. To maintain license exclusivity, Ansan made royalty
payments of $10,000 and $15,000 in 1995 and 1996, respectively. Ansan is
obligated to make minimum royalty payments of $20,000 in 1997, $25,000 in 1998
and $60,000 in each calendar year thereafter. In connection with this license
agreement, Bar-Ilan also entered into a stock purchase agreement with Ansan.
 
  In May 1996, Ansan signed a licensing agreement with Boehringer Ingelheim
GmbH ("Boehringer") to acquire the rights in the United States and the
European Union to develop a new intravenous formulation of the drug ApafantTM
for all clinical indications. Ansan intends to proceed with further
development and, if possible, clinical testing of the drug. Pursuant to the
agreement, Ansan made a license payment of $50,000 in 1996, and may be
obligated to make future milestone and royalty payments to Boehringer.
However, under certain circumstances, Boehringer may participate in further
development and commercialization of ApafantTM and, in such circumstances,
would be obligated to make milestone and royalty payments to Ansan.
 
                                     F-10

                          ANSAN PHARMACEUTICALS, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
                  NOTES TO FINANCIAL STATEMENTS--(CONTINUED)

4. LEASES
 
  Ansan leases facilities under an operating lease that expires in December
1998. Rent expense totaled $56,831 for the year ended December 31, 1996.
Future minimum lease payments total $54,479 for the years ending December 31,
1997 and 1998.
 
5. STOCKHOLDERS' EQUITY
 
 Preferred Stock
 
  In May 1994, Ansan issued 532,651 shares of Series A Preferred Stock to
Titan for cash of $992,592 and in exchange for forgiveness of a payable to
Titan of $1,449,064. Concurrent with the Offering, the preferred stock
automatically converted into 532,651 shares of common stock.
 
 Unit Offering
 
  In August 1995, Ansan issued 1,300,000 units, at $5.00 per unit in the
Offering. Each unit consisted of one share of common stock, one redeemable
class A warrant, and one class B warrant. The net proceeds (after
underwriter's discount and expenses, and other costs associated with the
Offering) totaled $5,107,000. At the closing of the Offering, all of Ansan's
outstanding preferred stock automatically converted into 532,651 shares of
common stock, and Ansan issued 352,557 shares of common stock to Titan in
exchange for forgiveness of $1,551,252 of intercompany debt. In September 1995
Ansan issued an additional 195,000 units, at $5.00 per share, in accordance
with the underwriter's over-allotment option. The net proceeds from the
exercise of the underwriter's over-allotment option (after underwriter's
discount and expenses) totaled $848,250. Each class A warrant entitles the
holder to purchase one share of common stock and one class B warrant at an
exercise price of $6.50 per share. Each class B warrant entitles the holder to
purchase one share of common stock an exercise price of $8.75 per share.
  In connection with the Offering, the holders of Ansan's common stock and
options to purchase common stock placed, on a pro rata basis, 363,740 shares
and options to purchase 36,260 shares of common stock into escrow (the "Escrow
Shares" and "Escrow Options", respectively). The Escrow Shares and Escrow
Options are not transferable or assignable; however, the Escrow Shares may be
voted. Holders of Escrow Options may exercise their options prior to their
release from escrow; however, the shares issuable upon any such exercise will
continue to be held in escrow. The Escrow Shares and Escrow Options will be
released from escrow if, and only if, certain earnings or market price
criteria have been met. If the conditions are not met by March 31, 2000, the
Escrow Shares and Escrow Options will be cancelled and contributed to Ansan's
capital.
 
  The release of Escrow Shares and Escrow Options held by employees, officers,
directors, consultants and their relatives will be deemed compensatory.
Accordingly, Ansan will recognize as compensation expense, during the period
in which the earnings or market price targets are met, a one-time charge to
reflect the then fair market value of the shares released from escrow. Such
charges could substantially reduce Ansan's net income or increase Ansan's
loss. The amount of compensation expense recognized by Ansan will not affect
Ansan's total stockholders' equity.
 
                                     F-11

                          ANSAN PHARMACEUTICALS, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
                  NOTES TO FINANCIAL STATEMENTS--(CONTINUED)

 Bridge Loan Warrants
 
  In May and June 1995, Ansan completed a bridge financing with gross proceeds
of $1,425,000. In conjunction with the bridge notes, Ansan issued class A
warrants to purchase an aggregate of 712,500 shares of Common Stock. In 1995,
Ansan recognized a $400,000 charge relating to the issuance of the warrants.
The principal and accrued interest on the bridge notes were repaid out of the
proceeds from the Offering.
 
 Common Stock
 
  During 1996, Ansan issued 40,000 shares of common stock to an employee,
resulting in $323,000 in compensation expense.
 
 Stock Purchase Agreements
 
  Through December 31, 1996, Ansan has issued 18,095 shares of common stock to
officers, employees and consultants under stock purchase agreements. Certain
shares are subject to repurchase by Ansan, as determined by the board of
directors, at the original issuance price. The repurchase rights will lapse as
the shares vest over a period of five years from the issuance date. During
1996, Ansan exercised its repurchase rights with respect to 804 shares. At
December 31, 1996, 1,178 shares are subject to repurchase.
 
 Stock Option Plan
 
  Under Ansan's 1993 Stock Option Plan which was amended and restated (the
"1993 Plan"), pursuant to which incentive stock options may be granted to
employees, and nonstatutory stock options may be granted to employees,
directors, consultants and affiliates of Ansan. A total of 141,710 shares of
Common Stock has been reserved and authorized for issuance under the 1993
Plan. No further options will be granted under Ansan's 1993 Plan. In May 1995,
Ansan adopted the 1995 Stock Option Plan (the "1995 Option Plan"). A total of
150,000 shares of Common Stock are reserved and authorized for issuance under
the 1995 Option Plan.
 
  Options granted under the 1993 and 1995 Plans expire no later than ten years
from the date of grant, except when the grantee is a 10% shareholder of Ansan
or an affiliate company, in which case the maximum term is five years from the
date of grant. The exercise price shall be at least 100%, 85% and 110% of the
fair value of the stock subject to the option on the grant date, as determined
by the board of directors, for incentive stock options, nonstatutory stock
options and options granted to 10% shareholders of Ansan or affiliate company,
respectively. Options granted under the 1993 Option Plan are exercisable
immediately upon grant, however, the shares issuable upon exercise of the
options are subject to repurchase by Ansan. Such repurchase rights will lapse
as the shares vest over a period of five years from the date of grant.
 
                                     F-12

                          ANSAN PHARMACEUTICALS, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
                  NOTES TO FINANCIAL STATEMENTS--(CONTINUED)

  Activity under the 1993 and 1995 Option Plans is summarized below:

                                            OUTSTANDING OPTIONS
                                SHARES     ---------------------
                             AVAILABLE FOR NUMBER OF  PRICE PER  WEIGHTED AVG.
                                 GRANT      SHARES      SHARE    EXERCISE PRICE
                             ------------- --------- ----------- --------------
                                                     
   Balance at December 31,
    1994....................     66,533      75,177  $0.29-$0.46     $0.31
     Additional shares
      authorized............    150,000         --           --        --
     Options granted........    (85,918)     85,918  $0.46-$5.00     $1.34
     Options cancelled......     31,325     (31,325)       $0.29     $0.29
                               --------     -------
   Balance at December 31,
    1995....................    161,940     129,770  $0.29-$5.00     $0.99
     Options granted........   (127,117)    127,177  $2.88-$3.38     $2.93
     Options exercised......         --     (33,152) $0.29-$0.58     $0.50
     Options cancelled......     14,509     (14,509) $0.29-$0.46     $0.42
                               --------     -------
   Balance at December 31,
    1996....................     49,332     209,226  $0.29-$5.00     $2.29
                               ========     =======

  Ansan recorded deferred compensation of $277,784 for the difference between
the grant price and the deemed fair value of Ansan's common stock for certain
options granted in the 12-month period prior to the offering. The deferred
compensation is being amortized to expense over the vesting period of the
options.
 
  From incorporation through December 31, 1994, Ansan issued options for
12,066 shares outside the 1993 Plan at exercise prices ranging from $0.06 to
$0.29. These options are exercisable immediately upon grant; however, the
shares issuable upon exercise of the options are subject to repurchase by
Ansan. Such repurchase right will lapse as the shares vest over a period of
three to five years from the date of grant.
 
  The following table summarizes information about options outstanding at
December 31, 1996:

                                             OPTIONS OUTSTANDING          OPTIONS EXERCISABLE
                                        ------------------------------ -------------------------
    RANGE OF                             WEIGHTED AVG.   WEIGHTED AVG.   OPTIONS   WEIGHTED AVG.
    EXERCISE                  OPTIONS      REMAINING       EXERCISE     CURRENTLY    EXERCISE
     PRICES                 OUTSTANDING CONTRACTUAL LIFE     PRICE     EXERCISABLE     PRICE
    --------                ----------- ---------------- ------------- ----------- -------------
                                                                    
   $0.06-$0.29.............    33,200         7.13           $0.24       25,329        $0.23
   $0.58...................    40,806         8.25           $0.58        4,145        $0.58
   $2.88-$5.00.............   142,117         9.42           $3.15       34,310        $3.18
                              -------                                    ------
                              216,123         8.85           $2.22       63,784        $1.88
                              =======                                    ======

  Of the 129,770 options outstanding at December 31, 1995, 36,607 were
exercisable at that date. All options granted under the 1993 Plan are
immediately exercisable, of which 44,532 shares of common stock underlying the
options as of December 31, 1996 would be subject to repurchase by Ansan should
certain options be exercised and the optionee's employment or consulting
relationship terminate.
 
 Stock Compensation
 
  Ansan has elected to follow APB 25 and related interpretations in accounting
for its stock options because, as discussed below, the alternative fair value
accounting provided for under SFAS 123 requires use of option valuation models
that were not developed for use in valuing employee stock options. Under APB
25, because the exercise price of Ansan's employee stock options equals the
market price of the underlying stock on the date of the grant, no compensation
expense is recognized.
 
                                     F-13

                          ANSAN PHARMACEUTICALS, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
                  NOTES TO FINANCIAL STATEMENTS--(CONTINUED)

  Pro forma information regarding the net income and earnings per share is
required by SFAS 123, and has been determined as if Ansan had accounted for
its employee stock options granted subsequent to 1994 under the fair value
method of that Statement. The fair value for these options was estimated at
the date of grant using a Black-Scholes option pricing model for the multiple
option approach with the following assumptions for 1996 and 1995: weighted-
average volatility factor of 0.7; no expected dividend payments; weighted-
average risk-free interest rates in effect of 6.27% and 6.00%, respectively;
and a weighted-average expected life of 4.04 and 4.46, respectively.
 
  The Black-Scholes option valuation model was developed for use in estimating
the fair value of traded options which have no vesting restrictions and are
fully transferable. In addition, option valuation models require the input of
highly subjective assumptions including the expected stock price volatility.
Because Ansan's employee stock options have characteristics significantly
different from those of traded options, and because changes in the subjective
input assumptions can materially affect the fair value estimate, in
management's opinion, the existing models do not necessarily provide a
reliable single measure of the fair value of Ansan's employee stock options.
 
  Based upon the above methodology, the weighted-average fair value of options
granted during the years ended December 31, 1995 and 1996 was $0.77 and $1.54,
respectively.
 
  For purposes of pro forma disclosures, the estimated fair value of the
options is amortized to pro forma net loss over the options' vesting period.
Ansan's pro forma information is as follows:

                                                           DECEMBER 31,
                                                      ------------------------
                                                         1995         1996
                                                      -----------  -----------
                                                             
     Pro forma net loss.............................. $(2,842,935) $(2,372,568)
     Pro forma net loss per share.................... $     (1.94) $     (0.98)

  Because SFAS 123 is applicable only to options granted subsequent to 1994,
its pro forma effect will not be fully reflected until 1998.
 
6. RELATED PARTY TRANSACTIONS
 
  On May 31, 1994, Ansan entered into an agreement with Titan providing for
the allocation of costs by Titan to Ansan for certain services provided during
1994 and 1995 in managing the affairs of Ansan, consisting primarily of
occupancy and equipment charges. These expenses are allocated among Titan and
Titan's subsidiaries and affiliates based upon the relative percentage of
effort expended by Titan on each subsidiary's affairs and relative use of
assets held by Titan, including those under a master capital equipment lease.
Management believes these allocations to be reasonable.
 
  Research and development expenses allocated to Ansan from Titan were
approximately $114,000 for the year ended December 31, 1995. General and
administrative expenses allocated to Ansan were $398,000 and $57,000 for the
years ended December 31, 1995 and 1996, respectively.
 
                                     F-14

                          ANSAN PHARMACEUTICALS, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
                  NOTES TO FINANCIAL STATEMENTS--(CONTINUED)

  No interest has been charged on the net payable to Titan. Activity under the
payable to Titan is summarized as follows:

                                                                    PERIOD FROM
                                                                    NOVEMBER 6,
                                          YEAR ENDED    YEAR ENDED    1992 TO
                                         DECEMBER 31,  DECEMBER 31, DECEMBER 31,
                                             1995          1996         1996
                                         ------------  ------------ ------------
                                                           
   Beginning balance.................... $ 1,292,960     $ 57,791   $       --
   Corporate cost allocations...........     375,867       56,865     1,160,940
   Working capital advances to Ansan....     181,678        3,225     2,198,719
   Repayment of debt to Titan...........    (241,462)         --       (241,462)
   Conversion of payable to Titan into
    capital stock.......................  (1,551,252)         --     (3,000,316)
                                         -----------     --------   -----------
   Ending balance....................... $    57,791     $117,881   $   117,881
                                         ===========     ========   ===========
     Average balance during the period.. $   830,972     $ 87,836   $   592,024
                                         ===========     ========   ===========

 Lease Commitment
 
  Titan is party to a master capital equipment lease, pursuant to which Ansan
and three other Titan majority-owned subsidiaries are jointly and severally
liable under a sublease and assignment agreement for monthly payments
(currently totaling $30,459) under the lease, should Titan be unable to
service the equipment lease. As of December 31, 1996, the amount outstanding
under the lease was approximately $747,000.
 
7. INCOME TAXES
 
   As of December 31, 1996, Ansan had federal net operating loss carryforwards
of approximately $8,600,000. The Company also had federal research and
development tax credit carryforwards of approximately $200,000. The net
operating loss and credit carryforwards will expire at various dates beginning
in 2008 through 2011, if not utilized.
 
  Utilization of the net operating losses and credits may be subject to a
substantial annual limitation due to the "change in ownership" provisions of
the Internal Revenue Code of 1986 and similar state provisions. The annual
limitation may result in the expiration of net operating losses and credits
before utilization.
 
  Significant components of Ansan's deferred tax assets for federal and state
income taxes are as follows:

                                                            DECEMBER 31,
                                                       ------------------------
                                                          1995         1996
                                                       -----------  -----------
                                                              
     Net operating loss carryforwards................. $ 2,200,000  $ 3,100,000
     Research credit carryforwards....................     100,000      200,000
     Capitalized research and development.............     300,000      300,000
     Valuation allowance..............................  (2,600,000)  (3,600,000)
                                                       -----------  -----------
                                                       $       --   $       --
                                                       ===========  ===========

  The net valuation allowance increased by $1,000,000 during the year ended
December 31, 1995.
 
                                     F-15

                          ANSAN PHARMACEUTICALS, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
                  NOTES TO FINANCIAL STATEMENTS--(CONTINUED)

8. SUBSEQUENT EVENTS
 
  In March 1997, Titan and Ansan entered into an agreement for financing
pursuant to which Titan advanced Ansan $1,000,000 in return for a debenture
(the "Debenture") which is convertible at any time prior to June 21, 1997 into
333,333 shares of common stock. The Debenture bears interest at prime plus 2%
and is due in March 1998. In connection with the issuance of the Debenture,
Ansan granted Titan an option (the "First Option") to acquire on additional
333,333 shares of Ansan common stock for an aggregate purchase price of
$1,000,000. The Debenture was not converted and the First Option expired on
June 21, 1997.
 
  In July 1997, Ansan entered into an Agreement and Plan of Reorganization and
Merger with Discovery Laboratories, Inc. ("Discovery"), a privately-held
development stage biotechnology company, pursuant to which Discovery will be
merged with and into Ansan. The parties also entered into a Stock Purchase
Agreement pursuant to which Discovery has purchased shares of a new class of
convertible preferred stock of Ansan for aggregate cash consideration of
$1,300,000, representing a common stock equivalent price of approximately
$1.40 per share.
 
  In connection with these transactions, Ansan has entered into a sublicense
agreement, and contingent upon completion of the merger, Titan will receive an
exclusive worldwide sublicense to certain butyrate compounds licensed by Ansan
for certain indications in exchange for Titan's payment of a 2% royalty on net
sales and Titan's transfer to Ansan of all its equity holdings in Ansan.
 
  The closing of the merger is subject to customary closing conditions,
including approval by the stockholders of Ansan and Discovery. If the merger
is completed, it is anticipated that the shareholders of Discovery will be
issued securities representing approximately 90% of the outstanding stock of
the combined entity. In the event the merger is not completed, the preferred
stock held by Discovery may, under certain circumstances, be convertible into
shares of common stock representing 51% of Ansan's then outstanding shares. In
such circumstances, Ansan would have the right to redeem the preferred stock
for $1,300,000 plus a redemption premium of $13,000 per month that the stock
is outstanding.
 
                                     F-16

                          ANSAN PHARMACEUTICALS, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
                            CONDENSED BALANCE SHEET

                                                       JUNE 30,    DECEMBER 31,
                                                         1997          1996
                                                     ------------  ------------
                                                     (UNAUDITED)     (NOTE A)
                                                             
                       ASSETS
                       ------
Current Assets:
  Cash and cash equivalents......................... $    497,790  $   245,778
  Short-term investments............................    1,200,000    1,500,000
  Prepaid expenses and other current assets.........       32,559       83,790
                                                     ------------  -----------
    Total current assets............................    1,730,349    1,829,538
Furniture and equipment, net........................       87,856       93,936
                                                     ------------  -----------
                                                     $  1,818,205  $ 1,923,474
                                                     ============  ===========
        LIABILITIES AND STOCKHOLDERS' EQUITY
        ------------------------------------
Current Liabilities:
  Accounts payable.................................. $    137,338  $    91,041
  Payable to Titan Pharmaceuticals, Inc. ...........      189,300      117,881
  Accrued sponsored research........................          --        36,330
  Accrued legal fees................................        5,935       26,327
  Other accrued liabilities.........................       11,370       62,457
  Debenture payable to Titan Pharmaceuticals, Inc...    1,000,000          --
                                                     ------------  -----------
    Total current liabilities.......................    1,343,943      334,036
Commitments
Stockholders' Equity:
  Common stock, at amounts paid in..................   10,699,996   10,850,017
  Deferred compensation.............................          --      (180,561)
  Deficit accumulated during the development stage..  (10,225,734)  (9,080,018)
                                                     ------------  -----------
    Total stockholders'equity.......................      474,262    1,589,438
                                                     ------------  -----------
                                                     $  1,818,205  $ 1,923,474
                                                     ============  ===========

- --------
Note A: The balance sheet at December 31, 1996 has been derived from the
        audited financial statements at that date but does not include all of
        the information and footnotes required by generally accepted accounting
        principles for complete financial statements.
 
                            See accompanying notes.
 
                                     F-17

                          ANSAN PHARMACEUTICALS, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
                       CONDENSED STATEMENTS OF OPERATIONS
                                  (UNAUDITED)

                                                                        PERIOD FROM
                                                                       INCORPORATION
                         THREE MONTHS ENDED    SIX MONTHS ENDED JUNE   (NOVEMBER 6,
                              JUNE 30,                  20,              1992) TO
                         --------------------  ----------------------    JUNE 30,
                           1997       1996        1997        1996         1997
                         ---------  ---------  -----------  ---------  -------------
                                                        
COSTS AND EXPENSES:
  Research and
   development.......... $ 244,487  $ 205,614  $   627,432  $ 462,976  $  6,607,974
  General and
   administrative.......   256,750    242,345      528,529    441,926     3,442,726
                         ---------  ---------  -----------  ---------  ------------
Loss from operations....  (501,237)  (447,959)  (1,155,961)  (904,902)  (10,050,700)
Other income/(expenses)
  Interest income.......    21,053     44,275       39,560     93,283       289,430
  Interest expense......   (26,174)       --       (29,315)       --       (464,464)
                         ---------  ---------  -----------  ---------  ------------
Net loss................ $(506,358) $(403,684) $(1,145,716) $(811,619) $(10,225,734)
                         =========  =========  ===========  =========  ============
Net loss per share...... $   (0.20) $   (0.17) $     (0.46) $   (0.34)
                         =========  =========  ===========  =========
Shares used in
 calculating net loss
 per share.............. 2,485,971  2,407,885    2,484,937  2,406,145
                         =========  =========  ===========  =========

                                      F-18

                          ANSAN PHARMACEUTICALS, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
                       CONDENSED STATEMENTS OF CASH FLOWS
                                  (UNAUDITED)

                                                                    PERIOD FROM
                                             SIX MONTHS ENDED      INCORPORATION
                                                 JUNE 30,          (NOVEMBER 6,
                                           ----------------------     1992 TO
                                              1997        1996     JUNE 30, 1997
                                           -----------  ---------  -------------
                                                          
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss.................................  $(1,145,716) $(811,619) $(10,225,734)
Adjustments to reconcile net loss to net
 cash used in
 operating activities
  Depreciation expense...................       16,843      9,251        40,826
  Amortization of debt discount..........          --         --        400,000
  Amortization of deferred compensation..       26,718     27,779       123,941
  Forgiveness of stockholder receivable..          --         --            205
  Issuance of common stock in exchange
   for consulting services...............          --         --         19,984
  Grant of common stock to employee......          --         --        155,000
  Changes in operating assets and
   liabilities:
    Prepaid expenses and other current
     assets..............................       51,201     79,589       (32,559)
    Accounts payable.....................       46,297     38,166       137,338
    Accrued sponsored research...........      (36,330)       730           --
    Accrued legal fees...................      (20,392)   (32,890)        5,935
    Other accrued liabilities............      (51,087)   (70,214)       11,370
                                           -----------  ---------  ------------
Net cash used in operating activities....   (1,112,466)  (759,208)   (9,363,694)
                                           -----------  ---------  ------------
CASH FLOWS FROM INVESTING ACTIVITIES
  Purchase of furniture and equipment....      (10,763)   (56,785)     (128,682)
  Purchase of short-term investments.....   (1,400,000)   (93,283)  (10,150,000)
  Sales of short-term investments........    1,700,000    900,000     8,950,000
                                           -----------  ---------  ------------
Net cash provided by (used in) investing
 activities..............................      289,237    749,932    (1,328,682)
                                           -----------  ---------  ------------
CASH FLOWS FROM FINANCING ACTIVITIES
  Proceeds from issuance of Series A
   preferred stock.......................          --         --        992,592
  Proceeds from issuance of common stock.        3,822      8,976     5,976,058
  Proceeds from related party notes......          --         --        220,000
  Proceeds from issuance of debenture to
   Titan Pharmaceuticals, Inc. ..........    1,000,000        --      1,000,000
  Payment on related party notes.........          --         --       (190,000)
  Issuance of notes payable..............          --         --      1,025,000
  Repayment of note payable..............          --         --     (1,425,000)
  Issuance of warrants to purchase common
   stock.................................          --         --        400,000
  Proceeds from stockholder receivable...          --         --          1,900
  Payable to Titan Pharmaceuticals, Inc..       71,419     24,660     3,189,616
                                           -----------  ---------  ------------
Net cash provided by financing
 activities..............................    1,075,241     33,636    11,190,166
                                           -----------  ---------  ------------
Net increase (decrease) in cash and cash
 equivalents.............................      252,012     24,360       497,790
Cash and cash equivalents, beginning of
 period..................................      245,778     45,202           --
                                           -----------  ---------  ------------
Cash and cash equivalents, end of period.  $   497,790  $  69,562  $    497,790
                                           ===========  =========  ============

                             See accompanying notes
 
                                      F-19

                          ANSAN PHARMACEUTICALS, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
                    NOTES TO CONDENSED FINANCIAL STATEMENTS
 
1. ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
 
 The Company
 
  Ansan was incorporated in the State of Delaware on November 6, 1992 to
engage in the development of analogs of butyric acid for the treatment of
cancer, blood disorders and other serious diseases. Ansan is in the
development stage.
 
 Relationship with Titan Pharmaceuticals, Inc.
 
  Titan, a biopharmaceutical company engaged, through the operations of its
subsidiaries and affiliates, in the development of new proprietary therapeutic
products for use in the fields of cancer, immunology, viral diseases, and
disorders of the central nervous system, was Ansan's parent until Ansan's
initial public offering (the "IPO") in August 1995. Subsequent to the IPO,
Titan's ownership interest was reduced to 43%.
 
  In March 1997, Ansan and Titan entered into an agreement for financing
pursuant to which Titan advanced Ansan $1,000,000 in return for a debenture
(the "Debenture") which was convertible at any time prior to June 21, 1997
into 333,333 shares of common stock. Titan did not convert the Debenture prior
to June 21, 1997. The Debenture bears interest at prime plus 2% and is due in
April 1998. In connection with the issuance of the Debenture, Ansan granted
Titan an option to acquire an additional 333,333 shares of Ansan common stock
for an aggregate purchase price of $1,000,000. The option expired unexercised
on June 21, 1997.
 
  Ansan contracts with Titan for limited financial and administrative
services. Titan has previously supplied working capital financing to Ansan and
may in the future provide such financing. As part of its affiliation with
Titan, Ansan and Titan have a number of members in common of their respective
boards of directors.
 
 Basis of Presentation
 
  The accompanying unaudited condensed financial statements have been prepared
in accordance with generally accepted accounting principals for interim
financial information and with the instructions to form 10-QSB and Article 10
of Regulation S-X. Accordingly, they do not include all of the information and
footnotes required by generally accepted accounting principals for complete
financial statements. In the opinion of management, all adjustments
(consisting of normal recurring accruals) considered for fair presentation
have been included. Operating results for the three- and six-month periods
ended June 30, 1997 are not necessarily indicative of the results that may be
expected for the year ending December 31, 1997. For further information, refer
to the consolidated financial statements and footnotes thereto included in the
Company's 1996 Annual Report on Form 10-KSB.
 
  Ansan's activities since incorporation have consisted primarily of
conducting research and development, performing business and financial
planning and raising capital. Accordingly, Ansan is considered to be in the
development stage and expects to incur increasing losses and require
additional financial resources to achieve commercialization of its products.
Ansan also depends on third parties to conduct certain research on Ansan's
behalf through various research arrangements. All of Ansan's current products
under development are the subject of license agreements that may require the
payment of future royalties.
 
                                     F-20

                          ANSAN PHARMACEUTICALS, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
                  NOTES TO FINANCIAL STATEMENTS--(CONTINUED)

 Net Loss Per Share
 
  Net loss per share for the three- and six-month periods ended June 30, 1996
and June 30, 1997 is computed using the weighted average number of common
shares outstanding, reduced by the number of shares held in escrow (see
Release of Escrowed Shares and Options below). Common equivalent shares are
excluded from the calculation as their effect is antidilutive.
 
  In February 1997, the Financial Accounting Standards Board issued Statement
No. 128 "Earnings Per Share", which is required to be adopted on December 31,
1997. At that time, Ansan will be required to change the method currently used
to compute earnings per share and to restate all prior periods. Under the new
requirements for calculating primary earnings per share, the dilutive effect
of stock options will be excluded. The impact is not expected to result in a
change in reported earnings per share for the three and six month periods
ended June 30, 1997 and June 30, 1996, as Ansan incurred net losses in those
periods, and accordingly, the calculation of earnings per share for those
periods excluded stock options as their effect was antidilutive.
 
 Release of Escrowed Shares and Options
 
  In connection with the IPO, certain stockholders of Ansan placed an
aggregate of 365,983 shares of Common Stock (the "Escrow Shares"), and the
current holders of certain options which are exercisable at less than the
initial public offering price of $5.00 placed options to purchase 34,017
shares (the "Escrow Options"), into escrow pending Ansan's attainment of
certain revenue or share price goals. The Securities and Exchange Commission
has taken the position with respect to the release of securities from escrow
that in the event any of the Escrow Shares or Escrow Options are released from
escrow to directors, officers, employees or consultants of Ansan, the release
will be treated, for financial reporting purposes, as a compensation expense
to Ansan. Accordingly, Ansan will, in the event of the release of the Escrow
Shares and Escrow Options, recognize during the period in which the earnings
or market price targets are met what could be a substantial one-time charge
which would substantially increase Ansan's loss or reduce or eliminate
earnings, if any, at such time. The amount of compensation expense recognized
by Ansan will not affect Ansan's total stockholders' equity.
 
2. SUBSEQUENT EVENTS
 
 Proposed Merger With Discovery Laboratories, Inc.
 
  In July of 1997 Ansan entered into an Agreement and Plan of Reorganization
and Merger with Discovery Laboratories, Inc. ("Discovery"), a privately-held
development stage biotechnology company, pursuant to which Discovery will be
merged with and into Ansan. The parties also entered into a Stock Purchase
Agreement pursuant to which Discovery has purchased shares of a new class of
convertible preferred stock of Ansan for aggregate cash consideration of
$1,300,000, representing a common stock equivalent price of approximately
$1.40 per share.
 
  In connection with these transactions, Ansan has entered into a sublicense
agreement with Titan. Pursuant to the agreement, and contingent upon
completion of the merger, Titan will receive an exclusive worldwide sublicense
to certain butyrate compounds licensed by Ansan for certain indications in
exchange for Titan's payment of a 2% royalty on net sales and Titan's transfer
to Ansan of all its equity holdings in Ansan.
 
  The closing of the merger is subject to customary closing conditions,
including approval by the stockholders of Ansan and Discovery. If the merger
is completed, it is anticipated that the shareholders of Discovery will be
issued securities representing approximately 90% of the outstanding stock of
the combined entity. In the event
 
                                     F-21

                          ANSAN PHARMACEUTICALS, INC.
                         (A DEVELOPMENT STAGE COMPANY)
 
                  NOTES TO FINANCIAL STATEMENTS--(CONTINUED)
 
the merger is not completed, the preferred stock held by Discovery may, under
certain circumstances, be convertible into shares of common stock representing
51% of Ansan's then outstanding shares. In such circumstances, Ansan would
have the right to redeem the preferred stock for $1,300,000 plus a redemption
premium of $13,000 per month that the stock is outstanding.
 
  The following selected unaudited pro forma balance sheet data gives effect
as of June 30, 1997, to the $1,300,000 investment, made by Discovery, pursuant
to the Stock Purchase Agreement.

                                               JUNE 30,               JUNE 30,
                                                 1997     ADJUSTMENT    1997
                                              ----------- ---------- ----------
                                                                        (PRO
                                              (UNAUDITED)              FORMA)
                                                            
   Current Assets...........................  $1,730,349  $1,300,000 $3,030,349
   Furniture and Equipment..................      87,856                 87,856
                                              ----------             ----------
   Total Assets.............................   1,818,205              3,118,205
                                              ==========             ==========
   Total Liabilities........................   1,343,943              1,343,943
   Total Stockholders' Equity...............     474,262  $1,300,000  1,774,262
                                              ----------             ----------
   Total Liabilities and Stockholders'
    Equity..................................  $1,818,205             $3,118,205
                                              ==========             ==========

                                     F-22

                        REPORT OF INDEPENDENT AUDITORS
 
The Board of Directors and Stockholders
Discovery Laboratories, Inc.
New York, New York
 
  We have audited the accompanying consolidated balance sheet of Discovery
Laboratories, Inc. and subsidiary (a development stage company) as at December
31, 1996, and the related consolidated statements of operations, changes in
stockholders' equity and cash flows for the two years ended December 31, 1996,
and the period from May 18, 1993 (inception) to December 31, 1996. These
financial statements are the responsibility of the Company's management. Our
responsibility is to express an opinion on these financial statements based on
our audits.
 
  We conducted our audits in accordance with generally accepted auditing
standards. Those standards require that we plan and perform the audits to
obtain reasonable assurance about whether the financial statements are free of
material misstatement. An audit includes examining, on a test basis, evidence
supporting the amounts and disclosures in the financial statements. An audit
also includes assessing the accounting principles used and significant
estimates made by management, as well as evaluating the overall financial
statement presentation. We believe that our audits provide a reasonable basis
for our opinion.
 
  In our opinion, the consolidated financial statements enumerated above
present fairly, in all material respects, the financial position of Discovery
Laboratories, Inc. and subsidiary at December 31, 1996 and the results of
their operations and their cash flows for the two years ended December 31,
1996, and the period from May 18, 1993 (inception) to December 31, 1996 in
conformity with generally accepted accounting principles.
 
                                               Richard A. Eisner & Company, LLP
 
New York, New York
February 12, 1997
 
                                     F-23

                  DISCOVERY LABORATORIES, INC. AND SUBSIDIARY
                         (A DEVELOPMENT STAGE COMPANY)
 
                          CONSOLIDATED BALANCE SHEETS

                                                                   DECEMBER 31,   JUNE 30,
                                                                       1996         1997
                                                                   ------------  -----------
                                                                                 (UNAUDITED)
                                                                           
                             ASSETS
                             ------
Current assets:
  Cash and cash equivalents......................................  $ 4,336,000   $ 1,478,000
  Investments in United States government obligations............   13,064,000    13,319,000
  Prepaid expenses...............................................       19,000        35,000
                                                                   -----------   -----------
    Total current assets.........................................   17,419,000    14,832,000
Computer equipment, net of depreciation (Note B).................       69,000       115,000
Licenses, net of amortization (Note E)...........................      701,000
                                                                   -----------   -----------
    TOTAL........................................................  $18,189,000   $14,947,000
                                                                   ===========   ===========
              LIABILITIES AND STOCKHOLDERS' EQUITY
              ------------------------------------
Liabilities:
  Accrued expenses...............................................  $   231,000   $   296,000
                                                                   -----------   -----------
Minority interest in preferred stock of subsidiary (Note G)......    2,200,000     2,200,000
                                                                   -----------   -----------
Commitments and contingencies (Notes E and G)
Stockholders' equity (Notes F, H and I):
  Series A convertible preferred stock, $.001 par value;
   7,000,000 shares authorized; 2,200,256 shares issued and
   outstanding (liquidation preference $29,703,000)..............        2,000         2,000
  Other preferred stock, $.001 par value; 3,000,000 shares
   authorized; none issued and outstanding.......................
  Common stock, $.001 par value, 50,000,000 shares authorized,
   6,712,256 shares issued and outstanding.......................        7,000         7,000
  Additional paid-in capital.....................................   19,003,000    18,992,000
  Deficit accumulated during the development stage...............   (3,254,000)   (6,550,000)
                                                                   -----------   -----------
    Total stockholders' equity...................................   15,758,000    12,451,000
                                                                   -----------   -----------
    TOTAL........................................................  $18,189,000   $14,947,000
                                                                   ===========   ===========

                See accompanying notes to financial statements.
 
                                      F-24

                  DISCOVERY LABORATORIES, INC. AND SUBSIDIARY
                         (A DEVELOPMENT STAGE COMPANY)
 
                     CONSOLIDATED STATEMENTS OF OPERATIONS

                                                  MAY 18, 1993                            MAY 18,
                               YEAR ENDED         (INCEPTION)     SIX MONTHS ENDED         1993
                              DECEMBER 31,             TO             JUNE 30,          (INCEPTION)
                          ----------------------  DECEMBER 31,  ----------------------  TO JUNE 30,
                            1995        1996          1996        1996        1997         1997
                          ---------  -----------  ------------  ---------  -----------  -----------
                                                                     (UNAUDITED)        (UNAUDITED)
                                                                      
Interest income.........  $          $   205,000  $   205,000   $          $   306,000  $   511,000
                          ---------  -----------  -----------   ---------  -----------  -----------
Expenses:
  Research and
   development..........               2,740,000    2,740,000      22,000    2,257,000    4,997,000
  General and
   administrative.......     17,000      692,000      710,000       9,000    1,345,000    2,055,000
  Interest..............                  11,000       11,000       2,000                    11,000
                          ---------  -----------  -----------   ---------  -----------  -----------
    Total expenses......     17,000    3,443,000    3,461,000      33,000    3,602,000    7,063,000
                          ---------  -----------  -----------   ---------  -----------  -----------
                            (17,000)  (3,238,000)  (3,256,000)    (33,000)  (3,296,000)  (6,552,000)
Minority interest in net
 loss of subsidiary.....                   2,000        2,000                                 2,000
                          ---------  -----------  -----------   ---------  -----------  -----------
NET (LOSS)..............  $ (17,000) $(3,236,000) $(3,254,000)  $ (33,000) $(3,296,000) $(6,550,000)
                          =========  ===========  ===========   =========  ===========  ===========
Pro forma net (loss) per
 share..................  $    (.01) $      (.65)               $    (.01) $      (.42)
                          =========  ===========                =========  ===========
Pro forma weighted
 average common shares
 outstanding............  1,714,766    4,943,768                3,028,329    7,836,363
                          =========  ===========                =========  ===========

 
                See accompanying notes to financial statements.
 
                                      F-25

                  DISCOVERY LABORATORIES, INC. AND SUBSIDIARY
                         (A DEVELOPMENT STAGE COMPANY)
 
           CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY

                                                                                         DEFICIT
                                                                                       ACCUMULATED
                            COMMON STOCK   PREFERRED STOCK      STOCK     ADDITIONAL   DURING THE
                          ---------------- ---------------- SUBSCRIPTIONS   PAID-IN    DEVELOPMENT
                           SHARES   AMOUNT  SHARES   AMOUNT  RECEIVABLE     CAPITAL       STAGE        TOTAL
                          --------- ------ --------- ------ ------------- -----------  -----------  -----------
                                                                            
Issuance of common
 shares, May 1993.......  1,132,500 $1,000           $         $(2,000)   $     1,000  $            $         0
Net loss................                                                                    (1,000)      (1,000)
Expenses paid on behalf
 of the Company.........                                         1,000                                    1,000
                          --------- ------ --------- ------    -------    -----------  -----------  -----------
Balance--December 31,
 1993...................  1,132,500  1,000                      (1,000)         1,000       (1,000)           0
Net loss................                                                                         0            0
Expenses paid on behalf
 of the Company.........                                             0                                        0
                          --------- ------ --------- ------    -------    -----------  -----------  -----------
Balance--December 31,
 1994...................  1,132,500  1,000                      (1,000)         1,000       (1,000)           0
Issuance of common
 shares, February 1995..    367,500  1,000                      (1,000)                                       0
Net loss................                                                                   (17,000)     (17,000)
Payment on stock
 subscriptions..........                                         2,000                                    2,000
Expenses paid on behalf
 of the Company.........                                                       18,000                    18,000
                          --------- ------ --------- ------    -------    -----------  -----------  -----------
Balance--December 31,
 1995...................  1,500,000  2,000                           0         19,000      (18,000)       3,000
Issuance of common
 shares, March 1996.....  2,750,000  3,000                                      3,000                     6,000
Issuance of private
 placement units August,
 October and November
 1996...................  2,200,256  2,000 2,200,256  2,000                18,932,000                18,936,000
Issuance of common
 shares for cash and
 compensation, September
 1996...................    212,000                                            42,000                    42,000
Exercise of Stock
 Options, July and
 October 1996...........     50,000                                             7,000                     7,000
Net loss................                                                                (3,236,000)  (3,236,000)
                          --------- ------ --------- ------    -------    -----------  -----------  -----------
Balance--December 31,
 1996...................  6,712,256  7,000 2,200,256  2,000          0     19,003,000   (3,254,000)  15,758,000
Private placement
 expenses...............                                                      (11,000)                  (11,000)
Net loss................                                                                (3,296,000)  (3,296,000)
                          --------- ------ --------- ------    -------    -----------  -----------  -----------
BALANCE--JUNE 30, 1997
 (UNAUDITED)............  6,712,256 $7,000 2,200,256 $2,000    $     0    $18,992,000  $(6,550,000) $12,451,000
                          ========= ====== ========= ======    =======    ===========  ===========  ===========

                See accompanying notes to financial statements.
 
                                      F-26

                  DISCOVERY LABORATORIES, INC. AND SUBSIDIARY
                         (A DEVELOPMENT STAGE COMPANY)
 
                     CONSOLIDATED STATEMENTS OF CASH FLOWS

                                                  MAY 18, 1993                          MAY 18, 1993
                               YEAR ENDED         (INCEPTION)     SIX MONTHS ENDED      (INCEPTION)
                              DECEMBER 31,             TO             JUNE 30,               TO
                          ----------------------  DECEMBER 31,  ----------------------    JUNE 30,
                            1995        1996          1996        1996        1997          1997
                          --------  ------------  ------------  ---------  -----------  ------------
                                                                     (UNAUDITED)        (UNAUDITED)
                                                                      
Cash flows from
 operating activities:
 Net loss...............  $(17,000) $ (3,236,000) $ (3,254,000) $ (33,000) $(3,296,000) $ (6,550,000)
 Adjustments to
  reconcile net loss to
  net cash (used in)
  operating activities:
 Write-off of acquired
  research and
  development supplies..               2,200,000     2,200,000                             2,200,000
 Write-off of licenses..                                                       683,000       683,000
 Depreciation and
  amortization..........                  24,000        24,000                  24,000        48,000
 (Increase) in prepaid
  expenses..............                 (18,000)      (18,000)                (16,000)      (35,000)
 Increase in accrued
  expenses..............                 230,000       230,000                  65,000       296,000
 Expenses paid on behalf
  of company............    17,000                      18,000                                18,000
 Employee stock
  compensation..........                  42,000        42,000                                42,000
                          --------  ------------  ------------  ---------  -----------  ------------
  Net cash (used in)
   operating activities.         0      (758,000)     (758,000)   (33,000)  (2,540,000)   (3,298,000)
                          --------  ------------  ------------  ---------  -----------  ------------
Cash flows from
 investing activities:
 Acquisition of computer
 equipment..............                 (83,000)      (83,000)                (52,000)     (135,000)
 Acquisition of license.                (711,000)     (711,000)  (111,000)                  (711,000)
 Purchase of investments
  in United States
  government
  obligations...........             (13,064,000)  (13,064,000)             (2,613,000)  (15,677,000)
 Redemption of
  investments in United
  States government
  obligations...........                                                     2,358,000     2,358,000
                          --------  ------------  ------------  ---------  -----------  ------------
  Net cash (used in)
   investing activities.             (13,858,000)  (13,858,000)  (111,000)    (307,000)  (14,165,000)
                          --------  ------------  ------------  ---------  -----------  ------------
Cash flows from
 financing activities:
 Private placement of
  units, net of
  expenses..............              18,936,000    18,936,000                 (11,000)   18,925,000
 Payment on stock
  subscriptions and
  proceeds on issuance
  of common stock.......     3,000        13,000        16,000      5,000                     16,000
 Short-term borrowings..                                          150,000
                          --------  ------------  ------------  ---------  -----------  ------------
  Net cash provided by
   (used in) financing
   activities...........     3,000    18,949,000    18,952,000    155,000      (11,000)   18,941,000
                          --------  ------------  ------------  ---------  -----------  ------------
NET INCREASE (DECREASE)
 IN CASH AND CASH
 EQUIVALENTS............     3,000     4,333,000     4,336,000     11,000   (2,858,000)    1,478,000
Cash and cash
 equivalents--beginning
 of period..............         0         3,000             0      3,000    4,336,000             0
                          --------  ------------  ------------  ---------  -----------  ------------
CASH AND CASH
 EQUIVALENTS--END OF
 PERIOD.................  $  3,000  $  4,336,000  $  4,336,000  $  14,000  $ 1,478,000  $  1,478,000
                          ========  ============  ============  =========  ===========  ============

                See accompanying notes to financial statements.
 
                                      F-27

                  DISCOVERY LABORATORIES, INC. AND SUBSIDIARY
                         (A DEVELOPMENT STAGE COMPANY)
 
                         NOTES TO FINANCIAL STATEMENTS
 
  (UNAUDITED WITH RESPECT TO INFORMATION AS OF JUNE 30, 1997 AND FOR THE SIX-
             MONTH PERIODS ENDED JUNE 30, 1997 AND JUNE 30, 1996)
 
(NOTE A)--THE COMPANY AND BASIS OF PRESENTATION:
 
  Discovery Laboratories, Inc. (the "Company") was incorporated in Delaware on
May 18, 1993 as MicroBio, Inc. The Company is a development stage company
formed to license and develop pharmaceutical products to treat a variety of
human diseases. The consolidated financial statements include the accounts of
the Company and its 75% owned subsidiary Acute Therapeutics, Inc. (see Note
G). Intercompany balances and transactions have been eliminated. No allocation
of the subsidiary's net loss has been attributed to the minority interest
since the accumulated losses exceed the minorities' common equity interest.
 
  In November 1996 the Company completed a private placement of its securities
and received aggregate net proceeds of approximately $19,000,000 (see Note F).
 
(NOTE B)--SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES:
 
 [1] Cash and cash equivalents:
 
  The Company considers all highly liquid investments purchased with a
maturity of three months or less to be cash equivalents.
 
 [2] Investments in United States Government obligations:
 
  The investments in United States Government obligations are comprised of
securities which are available for sale and are recorded at fair value with
any appreciation/depreciation recorded in the statement of operations.
 
 [3] Computer equipment:
 
  Computer equipment is recorded at cost. Depreciation is computed using the
straight-line method over the useful lives of the assets (five years).
 
 [4] Licenses:
 
  Through March 1997 licenses were capitalized and were being amortized on a
straight-line basis over their respective terms of 15 to 17 years. During the
quarter ended June 30, 1997, the Company determined that since they will not
pursue any alternative uses for the licenses, that all license costs would be
written off as research and development costs.
 
 [5] Research and development:
 
  Research and development costs are charged to operations as incurred.
 
 [6] Use of estimates:
 
  The preparation of financial statements in conformity with generally
accepted accounting principles requires management to make estimates and
assumptions that affect the reported amounts of assets and liabilities at the
date of the financial statements and the reported amounts of revenues and
expenses during the reporting period. Actual results could differ from those
estimates.
 
 [7] Long-lived assets:
 
  In accordance with Statement of Financial Accounting Standards No. 121,
"Accounting for the Impairment of Long-Lived Assets and for Long-Lived Assets
to be Disposed of", the Company records impairment losses
 
                                     F-28

                  DISCOVERY LABORATORIES, INC. AND SUBSIDIARY
                         (A DEVELOPMENT STAGE COMPANY)
 
                  NOTES TO FINANCIAL STATEMENTS--(CONTINUED)
 
on long-lived assets used in operations, including intangible assets, when
events and circumstances indicate that the assets might be impaired and the
undiscounted cash flows estimated to be generated by those assets are less
than the carrying amounts of those assets. No such losses have been recorded.
 
 [8] Stock-based compensation:
 
  During 1996, the Company adopted Statement of Financial Accounting
Standards, No. 123, "Accounting for Stock-Based Compensation" ("SFAS No.
123"). The provisions of SFAS No. 123 allow companies to either expense the
estimated fair value of stock options or to continue to follow the intrinsic
value method set forth in APB Opinion 25, "Accounting for Stock Issued to
Employees" ("APB 25") but disclose the pro forma effects on net income (loss)
had the fair value of the options been expensed. The Company has elected to
continue to apply APB 25 in accounting for its employee stock option incentive
plans. See Note H to the financial statements for further information.
 
 [9] Net loss per share:
 
  Pro forma net loss per share is computed based on the weighted average
number of common shares outstanding for the periods adjusted to reflect the
number of shares of Ansan Pharmaceuticals, Inc. common stock issuable to the
common stockholders of the Company upon consummation of the merger (Note J).
Common stock equivalents are not included in the calculation of net loss per
share as the effect would be anti-dilutive.
 
 [10] Interim financial statements:
 
  In the opinion of management, the interim financial statements include all
adjustments, consisting of normal recurring accruals, necessary for a fair
presentation of the Company's financial position at June 30, 1997 and results
of operations and cash flows for the six-month period ended June 30, 1997. The
financial statements as of June 30, 1997 and for the six months ended June 30,
1997 are not necessarily indicative of the results that may be expected for
the year ending December 31, 1997.
 
 [11] Recent accounting pronouncements:
 
  Recently issued accounting pronouncements concerning disclosure of
information about capital structure, reporting comprehensive income and
disclosure about segments of an enterprise and related information are not
expected to have a material effect on the presentation of the Company's
financial statements, the recent pronouncement on earnings per share provides
a simplified method for computing loss per share and will require retroactive
restatement when effective.
 
(NOTE C)--EMPLOYMENT AGREEMENTS:
 
  An employment agreement with the Company's president provides for an annual
salary of $175,000 through April 1999. Employment agreements with two
executive officers provide for aggregate annual salaries of $295,000 through
December 1999, subject to certain increases.
 
(NOTE D)--INCOME TAXES:
 
  At June 30, 1997, the Company has available for federal income tax purposes
net operating loss carryforwards of approximately $1,600,000 expiring through
2011, that may be used to offset future taxable income.
 
                                     F-29

                  DISCOVERY LABORATORIES, INC. AND SUBSIDIARY
                         (A DEVELOPMENT STAGE COMPANY)
 
                  NOTES TO FINANCIAL STATEMENTS--(CONTINUED)

  The principal difference between the deficit accumulated during the
development stage for financial reporting purposes and the net operating loss
carryforward for tax purposes is primarily due to the write-off of the
acquired research and development supplies and to certain general and
administrative costs which are not currently deductible for tax purposes. The
Company has provided a valuation reserve against the full amount of the
deferred tax asset of $2,590,000 arising from net operating loss benefit of
approximately $640,000, the research and development write-off of
approximately $1,130,000 and general and administrative costs of approximately
$820,000 since the likelihood of realization cannot be determined. The
valuation reserve increased by approximately $1,223,000 and $7,000 for the
years ended December 31, 1996 and December 31, 1995, respectively and
approximately $1,360,000 for the six months ended June 30, 1997. Pursuant to
Section 382 of the Internal Revenue Code, the utilization of this carryforward
may be limited due to ownership changes which have occurred or may occur.
 
(NOTE E)--LICENSE AGREEMENTS:
 
  [1] The Company entered into a license agreement with the Charlotte-
Mecklenburg Hospital Authority for the use of the active compound in
SuperVent, a therapy which the Company is clinically testing. The Company paid
a license issue fee of $86,400 and has agreed to pay royalties on future sales
and to pay future patent- related costs. The license expires upon expiration
of the underlying patents.
 
  [2] The Company entered into a license agreement with the Wisconsin Alumni
Research Foundation ("WARF") for the use of the patented compound ST-630 in
the treatment of post-menopausal osteoporosis. The Company paid WARF an option
fee of $25,000 in June 1996 and a license issue fee of $400,000 in October
1996 and is obligated to make future milestone payments aggregating $3,095,000
and pay royalties on future sales. The license expires upon expiration of the
underlying patents.
 
  [3] See Note G[1] with respect to a sublicense agreement with Johnson &
Johnson, Inc.
 
(NOTE F)--PRIVATE PLACEMENT:
 
  Pursuant to a private placement memorandum, the Company offered for sale
units, each unit consisting of 50,000 shares of Series A convertible preferred
stock and 50,000 shares of common stock. Preferred stockholders have voting
rights based upon the number of shares of common stock issuable upon
conversion of the preferred shares. Each share of preferred stock is initially
convertible at the option of the holders thereof into four shares of common
stock of the Company. The conversion rate will be adjusted under certain
circumstances as described in the private placement memorandum. From August
1996 through November 1996, the Company received net proceeds of approximately
$19,000,000 for the sale of approximately 44 units.
 
  Paramount Capital, Inc. ("Paramount") acted as the placement agent for the
offering and received a 9% commission plus a 4% nonaccountable expense
allowance aggregating $2,860,332. The Company also issued to Paramount
warrants to acquire 220,026 shares of Series A preferred stock at a price of
$11 per share, through November 8, 2006 and warrants to acquire 220,026 shares
of common stock at a price of $.25 per share, through November 8, 2006. The
warrants contain certain anti-dilution provisions and may be exercised on a
"net exercise" basis pursuant to a provision that does not require the payment
of any cash to the Company.
 
                                     F-30

                  DISCOVERY LABORATORIES, INC. AND SUBSIDIARY
                         (A DEVELOPMENT STAGE COMPANY)
 
                  NOTES TO FINANCIAL STATEMENTS--(CONTINUED)

(NOTE G)--INVESTMENT IN ACUTE THERAPEUTICS, INC.:
 
 [1] Formation of Acute Therapeutics, Inc.:
 
  On October 28, 1996, the Company invested $7.5 million in a newly formed
subsidiary, Acute Therapeutics, Inc. ("ATI"), in exchange for 600,000 shares
of Series A convertible preferred stock of ATI, representing 75% of the
outstanding voting securities of ATI following such transaction.
 
  Concurrently with the Company's investment in ATI, Johnson & Johnson, Inc.
("J & J"), Ortho Pharmaceuticals, Inc. (a wholly-owned subsidiary of J & J),
and ATI entered into an agreement (the "J & J License Agreement") granting an
exclusive license of KL4-Surfactant technology to ATI in exchange for certain
license fees ($200,000 of which was paid in November 1996), milestone payments
aggregating $2,750,000, royalties and 40,000 shares of ATI common stock. J & J
contributed its KL4-Surfactant raw material inventory and manufacturing
equipment to ATI in exchange for 2,200 shares of nonvoting Series B preferred
stock of ATI having a $2.2 million liquidation preference and a $100 per share
cumulative dividend. The inventory and equipment were valued at $2,200,000
(the value of the preferred shares issued to J & J) and were charged to
expense as their intended use is for research and development activities. The
Scripps Research Institute received 40,000 shares of common stock of ATI in
exchange for its consent to the J & J License Agreement.
 
  The founders of ATI purchased an aggregate of 120,000 shares of ATI common
stock for $.01 per share and were granted options to purchase an aggregate of
44,800 shares of common stock of ATI at an exercise price of $.01 per share
vesting after a five-year term, subject to acceleration and 40,000 shares of
common stock of ATI at an exercise price of $.32 per share vesting in April
1997.
 
 [2] Commitments:
 
  ATI entered into a four-year employment agreement with its President, Chief
Executive Officer and Chairman of the Board of Directors providing for a base
salary of $225,000 per year plus an initial sign-on bonus of $50,000 to be
paid the first week of January 1997, plus certain incentive bonuses.
 
  ATI also entered into a three year employment agreement with an officer
providing for an annual salary of $200,000 and various two-year consulting
agreements providing for aggregate annual fees of $300,000 plus royalties on
net commercial sales of licensed products sold by ATI or its sublicensees and
an 18-month consulting agreement providing for monthly fees of $7,500.
 
  ATI leases its office and laboratory space pursuant to an operating lease
requiring aggregate annual payments of approximately $67,000 through November
2001.
 
 [3] ATI stock option plan:
 
  ATI adopted the 1996 Stock Option/Stock Issuance Plan (the "ATI Plan")
consisting of a Discretionary Option Grant program for employees and an
Automatic Option Grant Program under which option grants will automatically be
made at periodic intervals to eligible nonemployee directors to purchase
shares of common stock, in either case at an exercise price equal to at least
85% of the fair market value of the common stock on the grant date. Under the
Discretionary Option Grant program, options will be granted to employees
either as incentive stock options or nonstatutory options and will vest over a
specified period of time (generally three to five years) as determined by the
ATI Board of Directors. ATI has reserved 234,800 shares of common stock for
issuance under these plans. Options for 173,800 shares of common stock have
been granted through January 1997.
 
                                     F-31

                  DISCOVERY LABORATORIES, INC. AND SUBSIDIARY
                         (A DEVELOPMENT STAGE COMPANY)
 
                  NOTES TO FINANCIAL STATEMENTS--(CONTINUED)

(NOTE H)--STOCK OPTIONS:
 
  In November 1996, the Company adopted its 1996 Stock Option/Stock Issuance
Plan which includes three equity programs (the "Discovery Plan"). Under the
Discretionary Option Grant Program, options to acquire shares of the Company's
common stock may be granted to eligible persons who are employees, nonemployee
directors, consultants and other independent advisors. Pursuant to the Stock
Issuance Program, such eligible persons may be issued shares of the Company's
common stock directly and under the Automatic Option Grant Program, eligible
directors will automatically receive option grants at periodic intervals. The
maximum number of shares of common stock which maybe issued over the term of
plan shall not exceed 1,250,000.
 
  In July and August, 1996, options to purchase 100,000 shares of the
Company's common stock were granted (all of which were immediately
exercisable), with a weighted average exercise price of $.125 per share.
Options to purchase 25,000 shares at $.10 per share were exercised in July
1996 and options to purchase 25,000 shares at $.20 per share were exercised in
November 1996.
 
  The Company applies APB 25 in accounting for the Discovery Plan and the ATI
Plan and, accordingly, recognizes compensation expense for the difference
between the fair value of the underlying common stock and the exercise price
of the option at the date of grant. The effect of applying SFAS No. 123 on pro
forma net loss is not necessarily representative of the effects on reported
net income or loss for future years due to, among other things, (1) the
vesting period of the stock options and the (2) fair value of additional stock
options in future years. Had compensation cost for the Company's stock option
plans been determined based upon the fair value of the options at the grant
date of awards under the plans consistent with the methodology prescribed
under SFAS No. 123, the Company's net loss for the year ended December 31,
1996 and the six months ended June 30, 1997 would have been approximately
$3,248,000 or $.77 per share and $2,688,000 or $.40 per share, respectively.
The fair value of the options granted are estimated as $.06 and $.07 per share
for the Discovery Plan and the ATI Plan, respectively for the year ended
December 31, 1996 and $.10 per share for the six months ended June 30, 1997,
on the date of grant using the Black-Scholes option-pricing model with the
following weighted average assumptions: dividend yield 0%, volatility of 0%,
risk-free interest rate of 6.7% for 1996 and 7% for 1997, and expected life of
ten years.
 
  Additional information with respect to the Discovery Plan stock option
activity is summarized as follows:

                                                         WEIGHTED-  WEIGHTED-
                                                          AVERAGE    AVERAGE
                                                         EXERCISE  CONTRACTUAL
                                                SHARES     PRICE      LIFE
                                                -------  --------- -----------
                                                          
      Outstanding at January 1, 1996...........       0
        Options granted........................ 100,000    $.125     10 years
        Options exercised...................... (50,000)     .15     10 years
                                                -------
      Outstanding December 31, 1996............  50,000      .10    9.1 years
        Options granted........................ 651,917      .20     10 years
                                                -------
      Outstanding June 30, 1997................ 701,917      .20    9.7 years
                                                =======
        Options exercisable at June 30, 1997... 468,917      .20    9.7 years
                                                =======

                                     F-32

                  DISCOVERY LABORATORIES, INC. AND SUBSIDIARY
                         (A DEVELOPMENT STAGE COMPANY)
 
                  NOTES TO FINANCIAL STATEMENTS--(CONTINUED)

  Additional information with respect to the ATI Plan stock option activity is
summarized as follows:

                                                           WEIGHTED-  WEIGHTED-
                                                            AVERAGE    AVERAGE
                                                           EXERCISE  CONTRACTUAL
                                                  SHARES     PRICE      LIFE
                                                  -------  --------- -----------
                                                            
      Outstanding at January 1, 1996.............       0
        Options granted.......................... 168,800    $.25      10 years
                                                  -------
      Outstanding December 31, 1996.............. 168,800     .25     9.8 years
        Options granted..........................  28,000     .68      10 years
        Options exercised........................  (2,000)    .32      10 years
                                                  -------
      Outstanding June 30, 1997.................. 194,800     .32     9.4 years
                                                  =======
        Options exercisable at June 30, 1997.....  53,250     .50     9.8 years
                                                  =======

(NOTE I)--STOCKHOLDERS' EQUITY:
 
  Common shares reserved for issuance:
 
  The Company has reserved shares of common stock for issuance upon conversion
of preferred stock and exercise of options as follows:

                                                                
      (i)   Preferred stock (Note F) (1)............................  17,602,048
      (ii)  Stock option plan--Discovery Plan.......................   1,200,000
      (iii) Placement agent warrants (Note F):
            Conversion of preferred stock...........................     880,103
            Common stock............................................     220,026

- --------
(1) Number of shares issuable assuming maximum conversion rate adjustment.
 
                                     F-33

                  DISCOVERY LABORATORIES, INC. AND SUBSIDIARY
                         (A DEVELOPMENT STAGE COMPANY)
 
                  NOTES TO FINANCIAL STATEMENTS--(CONTINUED)

(NOTE J)--SUBSEQUENT EVENT:
 
  On July 16, 1997 the Company entered into an agreement and plan of
reorganization and merger with Ansan Pharmaceuticals, Inc. ("Ansan"). Upon
completion of the merger, which is subject to various conditions, including
the approval of the stockholders of both companies, the Company's stockholders
will own approximately 90% of the combined entity. The merger will be
accounted for as a reverse acquisition with the Company as the acquirer for
financial reporting purposes. There is no assurance that the merger will be
consummated. Also on July 16, 1997 the Company purchased 13,000 shares of
Series A convertible preferred stock of Ansan for $1,300,000 which amount was
used by Ansan to repay certain debt owed to its principal stockholder. Ansan's
assets at June 30, 1997 consisted primarily of cash and short-term
investments.
 
  The following pro forma unaudited financial information gives effect to the
merger as if it had occurred at the beginning of the respective periods. A
nonrecurring charge of $2,434,000 for in-process research and development
which will be recorded by the Company in the historical financial statements
upon consummation of the merger has not been considered in the pro forma
results.

                                                                     SIX MONTHS
                                                        YEAR ENDED      ENDED
                                                       DECEMBER 31,   JUNE 30,
                                                           1996         1997
                                                       ------------  -----------
                                                               
     Interest income.................................. $   363,000   $   346,000
                                                       -----------   -----------
     Expenses:
       Research and development.......................   3,921,000     2,884,000
       General and administrative.....................   1,949,000     1,874,000
       Interest.......................................      11,000
                                                       -----------   -----------
         Total expenses...............................   5,881,000     4,758,000
     Minority interest in net loss of subsidiary......       2,000
                                                       -----------   -----------
     Net (loss)....................................... $(5,516,000)  $(4,412,000)
                                                       ===========   ===========
     Net (loss) per common share...................... $      (.83)  $      (.46)
                                                       ===========   ===========

                                     F-34

                                    ANNEX A
 
                 [Letterhead of Dakin Securities Corporation]
 
                                 July 16, 1997
 
Board of Directors
Ansan Pharmaceuticals, Inc.
400 Oyster Point Blvd., Suite 435
South San Francisco, CA 94080
 
Attention: Vaughan H.J. Shalson
 
Gentlemen:
 
  You have requested our opinion as to the fairness from a financial point of
view to the shareholders of Ansan Pharmaceuticals, Inc. ("Ansan" or the
"Company") of the Exchange Ratio (as defined herein) to be applied in
connection with the proposed merger (the "Merger") of Ansan with Discovery
Laboratories, Inc. ("Discovery"), pursuant to the Agreement and Plan of
Reorganization and Merger dated July 16, 1997 (the "Agreement") between Ansan
and Discovery.
 
  We understand that the terms of the Agreement provide that Discovery will be
merged into Ansan and that each outstanding share of Discovery common stock
will be converted into the right to receive 1.1671059 shares of common stock
of Ansan and each outstanding share of Discovery Series A convertible
preferred stock will be converted into the right to receive one share of Ansan
Series B preferred stock, which will each be convertible into 4.6684225 shares
of common stock of Ansan. (The above conversion rights are hereinafter
referred to as the "Exchange Ratio.")
 
  In arriving at our opinion, we reviewed a number of items including: (1) the
Agreement, the exhibits thereto and the terms of the proposed Merger; (2) the
Ansan Form 10-KSB for the fiscal year ended December 31, 1996 and the Form 10-
QSB, for the quarter ended March 31, 1997; (3) The Prospectus for the Ansan
initial public offering dated August 8, 1995; (4) internal documents provided
to us by Ansan which included descriptions of pharmaceutical products under
development, estimated timelines for clinical trials and commercialization of
such products; (5) recent articles concerning Ansan and press releases issued
by the Company; and (6) stock prices and trading history of Ansan common
stock. In addition, we interviewed the senior management of Ansan with regard
to the Company's drug portfolio, the Company's efforts to secure financing
from various sources including prospective corporate partners, an affiliate of
the Company, Titan Pharmaceuticals, and the equity markets. We also reviewed
the Form SB-2 Registration Statement and exhibits filed by Discovery with the
Securities and Exchange Commission.
 
  In arriving at our opinion we have relied upon the accuracy and completeness
of the financial and other information used by us without assuming any
responsibility for independent verification of such information. We also took
into account such factors as: the early state of clinical trials of Ansan's
pharmaceutical compounds and the need for funding to further develop these
compounds; the Company's limited financial resources; management's
representation that it had been unable to secure further funding from outside
third-party sources or Titan Pharmaceuticals; the difficulty of obtaining
funds from the equity markets and the imminent threat of delisitng from the
Nasdaq Small Cap Market.
 
                                      A-1

  We have not conducted a physical inspection of the properties and facilities
of Ansan or Discovery and have not made or obtained any evaluations or
appraisal of the assets or liabilities of either. We have, upon the advice of
Ansan and its legal advisors, assumed that the proposed merger will qualify as
a reorganization within the meaning of Section 368(a) of the Internal Revenue
Code of 1986, as amended, and therefore will be treated as a tax-free
transaction to the shareholders of Ansan. Our opinion is based upon market,
economic and other conditions as they exist on, and can be evaluated as of the
date of this letter.
 
  We will receive a fee from Ansan for rendering this fairness opinion, a
portion of which is contingent upon the consummation of the Merger. In
addition, Ansan has agreed to indemnify us for certain liabilities that may
arise out of rendering this opinion.
 
  Based upon the foregoing and such factors as we deem relevant, we are of the
opinion that the Exchange Ratio to be applied in the Merger is fair to the
Company from a financial point of view.
 
                                          Very truly yours,
 
                                          /s/ Dakin Securities Corporation
 
                                      A-2

                                    ANNEX B
 
                   [LETTERHEAD OF SANDS BROTHERS & CO. LTD.]
Board of Directors
Discovery Laboratories, Inc.
508 Madison Avenue
New York, NY 10022
 
Members of the Board:
 
  You have requested our opinion as to the fairness, from a financial point of
view, to the shareholders of Discovery Laboratories, Inc. ("Discovery") of the
contemplated merger transaction (the "Merger") between Discovery and Ansan
Pharmaceuticals, Inc. ("Ansan") pursuant to which the Discovery shareholders
and option holders, as a group, are to receive capital stock and options
aggregating approximately 90% of the issued and outstanding capital stock and
options of Ansan following consummation of the Merger.
 
  For purposes of our opinion and in connection with our review of the
proposed transaction, we have, among other things: (i) reviewed the agreement
relating to the Merger; (ii) analyzed Discovery's financial position including
reviewing the financial statements and other financial and operating data
concerning Discovery prepared by its management; (iii) reviewed certain
financial forecasts of Discovery prepared by its management; (iv) reviewed the
trading history and current stock price of Ansan; (v) reviewed and analyzed
Discovery's stage of clinical and drug development; (vi) reviewed and analyzed
the public market valuations of publicly traded biotechnology companies we
deemed comparable in quantitative and qualitative respects; (vii) reviewed and
compared ratios relative, and uniquely applicable to, the biotechnology
industry for those publicly-traded biotechnology companies and Discovery and;
(viii) visited the offices of Discovery and Ansan and met with management of
Discovery and Ansan.
 
  We have relied upon and assumed without independent verification the
accuracy and completeness of all of the financial and other information that
has been provided to us by Discovery and such other information utilized by us
in arriving at our opinion. With respect to Discovery's financial forecasts,
we have assumed that they have been reasonably prepared on bases reflecting
the best currently available estimates and judgments of the management of
Discovery as to the expected future performance of Discovery. We do not assume
any responsibility for the information or forecasts provided to us. We have
relied upon the assurances of the management of Discovery that they are
unaware of any facts that would make the information or forecasts provided to
us incomplete or misleading. In arriving at our opinion, we have not performed
or obtained any independent appraisal of the assets of Discovery.
 
  Our opinion is based solely upon the information available to us and the
economic, market and other circumstances as they exist as of the date hereof.
Events occurring after the date hereof could materially affect the assumptions
used in preparing this opinion.
 
  Based upon and subject to the foregoing, we are of the opinion that, as of
the date hereof, the consideration to be received by the Discovery
shareholders in connection with the Merger as described in the first paragraph
of this opinion letter is fair, from a financial point of view, to the
Discovery shareholders. This opinion is directed to and may be relied upon
only by the adressees hereto and may not be provided to or relied on by any
other person without the prior written consent of Sands Brothers & Co., Ltd.
Notwithstanding the foregoing to the contrary, this Opinion may be included in
its entirety in any proxy statement or other document distributed to the
shareholders of Discovery or Ansan in connection with the Merger.
 
                                          Sands Brothers & Co., Ltd.

                                          By /s/Howard D. Sterling
                                            -----------------------------------
                                            Howard D. Sterling
                                            Senior Vice President
                                            Corporate Finance

                                      B-1

                                    ANNEX C
 
                              AGREEMENT AND PLAN
                         OF REORGANIZATION AND MERGER
 
  This Agreement and Plan of Reorganization and Merger ("Agreement") is made
as of July 16, 1997 between ANSAN PHARMACEUTICALS, INC., a Delaware
corporation ("Ansan") and DISCOVERY LABORATORIES, INC., a Delaware corporation
("Discovery").
 
                                  BACKGROUND
 
  A. The parties hereto desire that Discovery shall be merged with and into
Ansan; that Ansan shall be the surviving corporation; and that each share of
the capital stock of Discovery which is outstanding immediately prior to the
effective time of the merger, other than those shares which become "Appraisal
Shares" within the meaning of Section 262 of the DGCL, be converted as set
forth in this Agreement into shares of the capital stock of Ansan.
 
  B. The parties intend that the merger constitute a "reorganization" under
Section 368(a), of the Code.
In consideration of the premises and agreements set forth herein, THE PARTIES
AGREE AS FOLLOWS:
 
                                   ARTICLE I
 
                                  DEFINITIONS
 
  The terms defined in this Article I shall, for purposes of this Agreement,
have the meanings specified in this Article I unless the context expressly or
by necessary implication otherwise requires:
 
  1.1 Affiliate. "Affiliate" shall have the meaning set forth in the 1933 Act.
 
  1.2 Affiliates Agreement. "Affiliates Agreement" shall have the meaning set
forth in Section 6.9 of this Agreement.
 
  1.3 Ansan Common Stock. "Ansan Common Stock" shall mean the Common Stock,
$.001 par value, of Ansan.
 
  1.4 Ansan Financial Statements. "Ansan Financial Statements" shall have the
meaning set forth in Section 5.2 of this Agreement.
 
  1.5 Ansan Preferred Stock. "Ansan Preferred Stock" shall mean the Series B
Convertible Preferred Stock of Ansan having the rights, preferences and
restrictions substantially as set forth in the Certificate of Designation
attached to this Agreement as Exhibit A, but subject to any further
adjustments to reflect the reverse stock split contemplated by this Agreement,
which Certificate of Designation shall be filed with the Secretary of State of
the State of Delaware on or before the Closing Date.
 
  1.6 Ansan Series A Preferred Stock. "Ansan Series A Preferred Stock" shall
mean the Series A Convertible Preferred Stock of Ansan having the rights,
preferences and restrictions set forth in the Certificate of Designation filed
with the Secretary of State of the State of Delaware on or about the date
hereof.
 
  1.7 Ansan Stock. "Ansan Stock" shall mean the Ansan Common Stock, Ansan
Preferred Stock and Ansan Series A Preferred Stock.
 
  1.8 ATI. "ATI" shall mean Acute Therapeutics, Inc., a Delaware corporation.
 
                                      C-1

  1.9 Appraisal Shares. "Appraisal Shares" shall mean all shares, if any, of
the outstanding capital stock of Discovery or Ansan for which appraisal rights
have been claimed under Section 262 of the DGCL.
 
  1.10 Balance Sheet. "Balance Sheet" shall have the meaning set forth in
Section 3.6 of this Agreement.
 
  1.11 Balance Sheet Date. "Balance Sheet Date" shall have the meaning set
forth in Section 3.6 of this Agreement
 
  1.12 Business Day. "Business Day" shall mean any day the New York Stock
Exchange is open for trading.
 
  1.13 Certificate. "Certificate" shall have the meaning set forth in Section
2.4.3 of this Agreement.
 
  1.14 Certificate of Merger. "Certificate of Merger" shall mean the
certificate of merger between Ansan and Discovery as required by Section 251
of the DGCL, in the form attached to this Agreement as Exhibit B.
 
  1.15 Closing. "Closing" shall mean the delivery by Ansan and Discovery of
the various documents contemplated by this Agreement or otherwise required in
order to consummate the Merger.
 
  1.16 Closing Date. "Closing Date" shall have the meaning set forth in
Section 2.2 of this Agreement.
 
  1.17 Code. "Code" shall mean the Internal Revenue Code of 1986, as amended.
 
  1.18 DGCL. "DGCL" shall mean the General Corporation Law of the State of
Delaware, as amended.
 
  1.19 Disclosure Statement. "Disclosure Statement" shall have the meaning set
forth in the first paragraph of Article III of this Agreement.
 
  1.20 Discovery Common Stock. "Discovery Common Stock" shall mean the Common
Stock, $.001 par value, of Discovery.
 
  1.21 Discovery Financial Statements. "Discovery Financial Statements" shall
have the meaning set forth in Section 4.3 of this Agreement.
 
  1.22 Discovery Option. "Discovery Option" shall have the meaning set forth
in Section 2.3 of this Agreement.
 
  1.23 Discovery Preferred Stock. "Discovery Preferred Stock" shall mean the
Series A Convertible Preferred Stock of Discovery.
 
  1.24 Discovery Stock. "Discovery Stock" shall mean both the Discovery Common
Stock and the Discovery Preferred Stock.
 
  1.25 Discovery Warrant. "Discovery Warrant" shall have the meaning set forth
in Section 2.3 of this Agreement.
 
  1.26 Discovery Working Capital. "Discovery Working Capital" shall mean an
amount equal to Discovery's current assets, less Discovery's current
liabilities, less any long-term debt owed to ATI, as determined in accordance
with generally accepted accounting principles and without consolidating the
accounts of ATI with Discovery for the purposes of such calculation.
 
  1.27 Effective Time. "Effective Time" shall mean the time when the
Certificate of Merger is filed with the Secretary of State of the State of
Delaware and the Merger becomes effective.
 
  1.28 Exchange Act. "Exchange Act" shall mean the Securities and Exchange Act
of 1934, as amended.
 
                                      C-2

  1.29 Exchange Agent. "Exchange Agent" shall have the meaning set forth in
Section 2.4.1 of this Agreement.
 
  1.30 Fair Market Value of Ansan Common Stock. "Fair Market Value of Ansan
Common Stock" shall mean the average of the last reported closing bid prices
of the Ansan Common Stock on the Nasdaq SmallCap Market on the 20 trading days
immediately preceding the Closing Date.
 
  1.31 Holders. "Holders" shall mean holders of Discovery Stock immediately
prior to the Effective Time.
 
  1.32 Lockup Agreement. "Lockup Agreement" shall have the meaning set forth
in Section 6.10 of this Agreement.
 
  1.33 Merger. "Merger" shall mean the merger of Discovery with and into Ansan
in accordance with this Agreement, the Certificate of Merger and applicable
law.
 
  1.34 Proxy Statement. "Proxy Statement" shall mean the Proxy Statement to be
mailed to the stockholders of Ansan in connection with the Merger.
 
  1.35 shall mean the Registration Statement on Form S-4 to be filed by Ansan
with the SEC in connection with the issuance of Ansan Stock pursuant to the
Merger.
 
  1.36 SEC. "SEC" shall mean the Securities and Exchange Commission.
 
  1.37 Subsidiary. "Subsidiary" shall mean, with respect to a particular party
hereto, any corporation or other organization, whether incorporated or
unincorporated, of which at least a majority of the securities or interests
having by the terms thereof ordinary voting power to elect a majority of the
board of directors or others performing similar functions with respect to such
corporation or other organization is directly or indirectly owned by such
party or by one or more Subsidiaries, or by such party and one or more
Subsidiaries.
 
  1.38 Titan. "Titan" shall mean Titan Pharmaceuticals Inc., a Delaware
corporation.
 
  1.39 Titan Agreement. "Titan Agreement" shall mean the agreement in the form
attached hereto as Exhibit C.
 
  1.40 Act. "1933 Act" shall mean the Securities Act of 1933, as amended, and
the rules, regulations and forms thereunder.

                                  ARTICLE II
 
                   MERGER, CLOSING AND CONVERSION OF SHARES
 
  2.1 Merger. Subject to and in accordance with the terms and conditions of
the Agreement and the Certificate of Merger, on the Closing Date, Ansan and
Discovery shall execute and file the Certificate of Merger with the Secretary
of State of the State of Delaware, whereupon Discovery shall be merged with
and into Ansan pursuant to Sections 251 of the DGCL.
 
  2.2 Closing. The Closing shall take place at the offices of Heller Ehrman
White & McAuliffe, 525 University Avenue, Palo Alto, California 94301, on
November 3, 1997 at 1:00 pm, or if the conditions set forth in Articles VI and
VII have not been satisfied or waived by such date, on the earliest
practicable date, but in no event later than December 31, 1997, after
satisfaction or waiver of such conditions (the "Closing Date").
 
  2.3 Conversion of Shares.
 
    2.3.1 In accordance with this Agreement and the Certificate of Merger:
 
      (a) each share of Discovery Common Stock outstanding immediately
    prior to the Effective Time (except those shares of Discovery Common
    Stock which are Appraisal Shares and whose Holder and
 
                                      C-3

    Discovery do not thereafter agree in writing should not be treated as
    Appraisal Shares) shall, by virtue of the Merger and without any action
    on the part of the holder thereof be converted, at and as of the
    Effective Time into 1.1641085 shares of Ansan Common Stock. Holders of
    Discovery Common Stock shall receive only whole shares of Ansan Common
    Stock, with Ansan being authorized to pay in cash, in lieu of any
    resulting fractional share, the Fair Market Value of Ansan Common Stock
    multiplied by such fraction so as to eliminate the necessity for the
    issuance of fractional shares upon such conversion,
 
      (b) each share of Discovery Preferred Stock outstanding immediately
    prior to the Effective Time (except those shares of Discovery Preferred
    Stock which are Appraisal Shares and whose Holder and Discovery do not
    thereafter agree in writing should not be treated as Appraisal Shares)
    shall, by virtue of the Merger and without any action on the part of
    the holder thereof be converted, at and as of the Effective Time into
    one (1) share of Ansan Preferred Stock. Holders of Discovery Preferred
    Stock shall receive only whole shares of Ansan Preferred Stock; in lieu
    of any fractional share of Ansan Preferred Stock, Holders shall receive
    in cash the fair market value of such fractional share valuing Ansan
    Preferred Stock on an as-converted to Ansan Common Stock basis at the
    Fair Market Value of the Ansan Common Stock,
 
      (c) each of the outstanding underwriter warrants and stock options to
    purchase Discovery Stock ("Discovery Warrant" and "Discovery Option",
    respectively) shall thereafter entitle the holder thereof to receive,
    upon exercise thereof, 1.1641085 shares of Ansan Common Stock for each
    share of Discovery Common Stock subject to such Discovery Option or
    Discovery Warrant, at an exercise price for each full share of Ansan
    Common Stock equal to the exercise price per share of Discovery Common
    Stock with respect to such Discovery Option or Discovery Warrant
    multiplied by 1.1641085, which exercise price per share shall be
    rounded up to the nearest two-place decimal, and one (1) share of Ansan
    Preferred Stock for each share of Discovery Preferred Stock subject to
    such Discovery Option or Discovery Warrant, at an exercise price equal
    to the exercise price stated in such Discovery Option or Discovery
    Warrant. The number of shares of Ansan Stock that may be purchased by a
    holder on the exercise of any Discovery Option or Discovery Warrant
    shall not include any fractional share of Ansan Stock but shall be
    rounded down to the next lower whole share of Ansan Stock. Ansan shall
    assume in full such Discovery Options and Discovery Warrants and all of
    Discovery's other rights and obligations thereunder and under all
    agreements relating thereto (including without limitation registration
    rights in favor of the holders of the Discovery Warrants) and shall
    give notice to such effect to the Holder thereof promptly after the
    Closing. After such assumption, Ansan shall issue, upon any partial or
    total exercise of any Discovery Option or Discovery Warrant, in lieu of
    shares of Discovery Stock, the number of shares of Ansan Stock to which
    the holder of the Discovery Option or Discovery Warrant is entitled
    pursuant to this Agreement,
 
      (d) any Ansan Stock held by Discovery immediately prior to the
    Effective Time shall be cancelled, and
 
      (e) in accordance with the foregoing, Ansan shall issue Ansan Common
    Stock and Ansan Preferred Stock and assume the obligations to issue
    Ansan Common Stock and Ansan Preferred Stock upon exercise of Discovery
    Options and Discovery Warrants which, on as converted and exercised
    basis, represent 20,208,807 shares of Ansan Common Stock.
 
  2.4 Exchange of Certificates.
 
    2.4.1 Prior to the Closing Date, Ansan shall appoint Continental Stock
  Trust & Transfer, or such other bank or trust company selected by Ansan as
  Discovery may approve, to act as exchange agent (the "Exchange Agent") in
  the Merger.
 
    2.4.2 Promptly after the Closing Date, but in no event later than three
  Business Days thereafter, the Exchange Agent shall make available for
  exchange in accordance with this Section 2.4.2 the shares of Ansan Stock
  issuable pursuant to Section 2.3 in exchange for outstanding shares of
  Discovery Stock.
 
                                      C-4

    2.4.3 As soon as practicable after the Closing Date, the Exchange Agent
  shall mail to each holder of record of a stock certificate that,
  immediately prior to the Closing Date, represented outstanding shares of
  Discovery Stock (a "Certificate") whose shares are being converted into
  Ansan Common Stock or Ansan Preferred Stock pursuant to Section 2.3, (i) a
  letter of transmittal (which shall specify that delivery shall be effected,
  and risk of loss and title to the Certificates shall pass, only upon
  delivery of the Certificates to the Exchange Agent and shall be in such
  form and have such other provisions as Ansan may reasonably specify), and
  (ii) instructions for use in effecting the surrender of the Certificates in
  exchange for certificates evidencing Ansan Common Stock or Ansan Preferred
  Stock. Upon surrender of a Certificate for cancellation to the Exchange
  Agent or to such other agent or agents as may be appointed by Ansan,
  together with such letter of transmittal, duly executed, the holder of such
  Certificate shall be entitled to receive in exchange therefor (subject to
  Section 2.4) the number of shares of Ansan Common Stock or Ansan Preferred
  Stock to which the holder of Discovery Stock is entitled pursuant to
  Section 2.3 hereof and is represented by the Certificate so surrendered.
  The Certificate so surrendered shall forthwith be cancelled. In the event
  of a transfer of ownership of Discovery Stock that is not registered in the
  transfer records of Discovery, or its transfer agent, Ansan Common Stock or
  Ansan Preferred Stock may be delivered to a transferee if the Certificate
  representing such Discovery Stock is presented to the Exchange Agent and
  accompanied by all documents required to evidence and effect such transfer
  and to evidence that any applicable stock transfer taxes have been paid.
  Until surrendered as contemplated by this Section 2.4.3, each Certificate
  shall be deemed at any time after the Closing Date to represent the right
  to receive upon such surrender such whole number of shares of Ansan Common
  Stock or Ansan Preferred Stock as provided by Section 2.3 and the
  provisions of the DGCL.
 
    2.4.4 No dividends or distributions payable to Holders after the
  Effective Time, or cash payable in lieu of fractional shares, shall be paid
  to the Holder of any unsurrendered Certificate until the Holder of the
  Certificate shall surrender such Certificate.
 
    2.4.5 All Ansan Common Stock and Ansan Preferred Stock delivered upon the
  surrender for exchange of shares of Discovery Stock in accordance with the
  terms hereof shall be deemed to have been delivered in full satisfaction of
  all rights pertaining to such shares of Discovery Stock. There shall be no
  further registration of transfers on the stock transfer books of Discovery
  or its transfer agent of the shares of Discovery Stock that were
  outstanding immediately prior to the Effective Time. If, after the Closing
  Date, Certificates are presented for any reason, they shall be cancelled
  and exchanged as provided in Section 2.4.
 
  2.5 Appraisal Shares. Holders of Appraisal Shares shall have those rights,
but only those rights, of holders of "appraisal shares" under Section 262 of
the DGCL. Each party shall give the other party prompt notice of any demand,
purported demand or other communication received by it with respect to any
Appraisal Shares or shares claimed to be Appraisal Shares. Each party agrees
that, without the prior written consent of the other party, which consent
shall not be unreasonably withheld, it shall not voluntarily make any payment
with respect to, or settle or offer to settle, any demand or purported demand
respecting such shares.
 
  2.6 Registration on Form S-4. The Ansan Common Stock to be issued in the
Merger (and the Ansan Common Stock underlying the Ansan Preferred Stock to be
issued in the Merger) and the Ansan Preferred Stock to be issued in the Merger
shall be registered under the 1933 Act on Form S-4. As promptly as practicable
after the date hereof, Ansan shall prepare and file with the SEC the Proxy
Statement and any other documents required by the Exchange Act in connection
with the Merger, and Ansan shall prepare and file with the SEC the Form S-4
and any other documents required by the 1933 Act in connection with the Merger
(including, without limitation the filing of Form 8-K by Ansan when
appropriate). Ansan shall use its reasonable efforts to have the Form S-4
declared effective under the 1933 Act as promptly as practicable after such
filing. Ansan shall afford Discovery a reasonably opportunity to review and
comment on the Proxy Statement prior to its distribution. To the greatest
extent practicable, information required to be disclosed in both the Proxy
Statement and the consent solicitation to be distributed by Discovery to its
stockholders pursuant to Section 2.7 shall be disclosed in an identical
manner. Ansan shall also take any action required to be taken under any
applicable state securities or "blue sky" laws in connection with the issuance
of the Ansan Stock in the Merger. Discovery shall furnish to Ansan all
 
                                      C-5

information in Discovery's possession and reasonably accessible by Discovery
concerning Discovery and ATI and the holders of Discovery Stock as may be
reasonably requested in connection with any action contemplated by this
Section 2.6.
 
  2.7 Information Statement. Discovery shall afford Ansan a reasonable
opportunity to review and comment on any solicitation materials, including
solicitation of action by written consent, that Discovery distributes to its
stockholders in connection with the Merger. To the greatest extent
practicable, information required to be disclosed in both the Proxy Statement
and any such solicitation materials shall be disclosed in an identical manner.
 
  2.8 Tax Free Reorganization. The parties intend to adopt this Agreement as a
tax free plan of reorganization and to consummate the Merger in accordance
with the provisions of Section 368(a) of the Code.
 
  2.9 Ansan Common Stock Split. If mutually agreed upon by Ansan and
Discovery, prior to the Effective Time, Ansan shall file a Restated
Certificate of Incorporation with the Delaware Secretary of State for the
recombination of each authorized share of Ansan Common Stock into such lesser
number of shares of Ansan Common Stock as shall be mutually agreed upon by
Ansan and Discovery to maintain the listing of the Ansan Common Stock on the
Nasdaq SmallCap Market. Such recombined Ansan Common Stock shall have the same
rights, privileges and restrictions as the currently authorized Ansan Common
Stock with Ansan being authorized to pay in cash, in lieu of any resulting
fractional share, the Fair Market Value of Ansan Common Stock so as to
eliminate the necessity for the issuance of fractional shares upon such
recombination. The exchange ratios and provisions in the preceding sections of
this Article II shall be adjusted to reflect any recombination of Ansan Common
Stock pursuant to this Section 2.9 of the Agreement.
 
                                  ARTICLE III
 
                     MUTUAL REPRESENTATIONS AND WARRANTIES
 
  Each of Ansan, Discovery and ATI is a "Company" as contemplated by this
Article III. Any disclosure delivered by one Company to the other hereto
pursuant to this Article shall have been delivered on or prior to the date
hereof shall specifically refer to this Agreement and shall identify the
Section of this Agreement requiring the delivery of such disclosure (each such
disclosure being referred to herein as a " Disclosure Statement"). Except as
set forth in the Disclosure Statement of such Company and except for the
transactions contemplated by this Agreement, Ansan hereby represents and
warrants to Discovery and Discovery hereby represents and warrants to Ansan,
that:
 
  3.1 Organization and Authority. The Company and each of its Subsidiaries:
(i) is a corporation duly organized, validly existing and in good standing
under the laws of the jurisdiction of its incorporation; (ii) has all
necessary corporate power to own and lease its properties, to carry on its
business as now being conducted and to enter into and perform this Agreement
and all agreements to which the Company is or will be a party that are
exhibits to this Agreement; and (iii) is qualified to do business in all
jurisdictions in which the failure to so qualify would have a material adverse
effect on its business or financial condition. The Company has made available
to the other party for inspection complete and correct copies of its
Certificate of Incorporation, as amended, Bylaws as in effect on the date
hereof and a record of any and all proceedings and actions at all meetings of,
or taken by written consent by, its Board of Directors and stockholders, since
its inception, in each case, certified as true, complete and correct copies by
the Company's Secretary.
 
  3.2 Authority Relating to this Agreement; No Violation of Other Instruments.
 
    3.2.1 The execution and delivery of this Agreement and all agreements to
  which the Company is or will be a party that are exhibits to this Agreement
  and the performance hereunder and thereunder by the Company have been duly
  authorized by all necessary corporate action on the part of the Company,
  other
 
                                      C-6

  than stockholder approval as is contemplated by this Agreement, and,
  assuming execution of this Agreement and such other agreements by the other
  party thereto, this Agreement and such other agreements will constitute
  legal, valid and binding obligations of the Company, enforceable against
  the Company in accordance with their terms, subject as to enforcement: (i)
  to bankruptcy, insolvency, reorganization, arrangement, moratorium and
  other laws of general applicability relating to or affecting creditors'
  rights; and (ii) to general principles of equity, whether such enforcement
  is considered in a proceeding in equity or at law.
 
    3.2.2 Neither the execution of this Agreement nor any other agreement to
  which the Company is or will be a party that is an exhibit to this
  Agreement nor the performance of any of them by the Company will: (i)
  conflict with or result in any breach or violation of the terms of (a) any
  decree, judgment or order of any court or other governmental body of which
  the Company has knowledge or (b) any law or regulation now in effect
  applicable to the Company; (ii) conflict with, or result in, with or
  without the passage of time or the giving of notice, a material breach of
  any of the terms, conditions and provisions of, or constitute a material
  default under or otherwise give another party the right to terminate, or
  result in the creation of any lien, charge, or encumbrance upon any of the
  material assets or properties of the Company pursuant to, any indenture,
  mortgage, lease, agreement or other instrument to which the Company is a
  party or by which it or any of its assets or properties are bound,
  including all Contracts (as defined in Section 3.16); (iii) permit the
  acceleration of the maturity of any material indebtedness of the Company or
  of any other person secured by the assets or properties of the Company; or
  (iv) violate or conflict with any provision of the Company's Certificate of
  Incorporation, Bylaws, or similar organizational instruments.
 
    3.2.3 Except as contemplated in Sections 2.6, 6.8, 6.16, 7.6 and 7.12 of
  this Agreement, no consent from any third party and no consent, approval or
  authorization of, or declaration, filing or registration with, any
  government or regulatory authority is required to be made or obtained by
  the Company in order to permit the execution, delivery or performance of
  this Agreement or any other agreement to which the Company is or will be a
  party that is an exhibit to this Agreement by the Company, or the
  consummation of the transactions contemplated by this Agreement and such
  other agreements.
 
  3.3 Compliance with Law. The Company holds, and has at all times since
December 31, 1995 held, all licenses, permits and authorizations necessary for
the lawful conduct of the Company's business wherever conducted pursuant to
all applicable statutes, laws, ordinances, rules and regulations of all
governmental bodies, agencies and subdivisions having, asserting or claiming
jurisdiction over the Company or over any part of the Company's operations,
and the Company knows of no violation thereof. The Company is not in violation
of any decree, judgment, or order known to it, or any law or regulation of any
court or other governmental body (including without limitation, applicable
environmental protection legislation and regulations, equal employment and
civil rights regulations, wages, hours and the payment of social security
taxes and occupational health and safety legislation), which violation could
have a material adverse effect on the condition, financial or otherwise,
assets, liabilities, business or results of operations of the Company.
 
  3.4 Investments in Others. Section 3.4 of the Disclosure Statement of the
Company contains a list of each corporation, association, partnership, joint
venture or other entity in which the Company, directly or indirectly, owns an
equity interest and sets forth the Company's percentage interest by voting
rights and by profits, in each such entity. Except for the entities identified
in such list, the Company does not conduct any part of its business operations
through any subsidiaries or through any other entity in which the Company has
an equity investment.
 
  3.5 Tax Returns and Payments. All tax returns and reports with respect to
the Company required by law to be filed under the laws of any jurisdiction,
domestic or foreign, have been duly and timely filed and all taxes, fees or
other governmental charges of any nature which were required to have been paid
have been paid or provided for. The Company has no knowledge of any unpaid
taxes or any actual or threatened assessment of deficiency or additional tax
or other governmental charge or a basis for such a claim against the Company.
The Company has no knowledge of any tax audit of the Company by any taxing or
other authority in connection with any of its fiscal years; the Company has no
knowledge of any such audit currently pending or threatened, and the Company
has no knowledge of any tax liens on any of the properties of the Company.
 
                                      C-7

  3.6 Absence of Certain Changes or Events. Since the date (the "Balance Sheet
Date") of the most recent balance sheet delivered by the Company to the other
party hereto pursuant to Section 4.3 or 5.2, as the case may be (the "Balance
Sheet"), except as contemplated by this Agreement, there have been no material
changes in the condition, financial or otherwise, assets, liabilities,
business or the results of operations of the Company, other than changes in
the ordinary course of business which in the aggregate have not been
materially adverse. Without limiting the foregoing, since the Balance Sheet
Date, except as contemplated by this Agreement:
 
    (i) the Company has not entered into any transaction other than in the
  ordinary course of business;
 
    (ii) there have been no losses or damage to any of the assets or
  properties of the Company due to fire or other casualty, whether or not
  insured, amounting to more than Ten Thousand Dollars ($10,000) in the
  aggregate;
 
    (iii) there has been no increase or decrease in the rates of direct
  compensation payable or to become payable by the Company to any employee,
  agent or consultant (other than routine increases made in the ordinary
  course of business or pursuant to a collective bargaining agreement), or
  any bonus, percentage compensation, service award or other like benefit,
  granted, made or accrued to or to the credit of any such employee, agent or
  consultant, or any material welfare, pension, retirement or similar payment
  or arrangement made or agreed to be made by the Company (other than such
  events occurring pursuant to any previously existing benefit plan or
  collective bargaining agreement);
 
    (iv) the Company has not executed, created, amended or terminated any
  contract except in the ordinary course of business;
 
    (v) the Company has not declared or paid any dividend or made any
  distribution on its capital stock, nor redeemed, purchased or otherwise
  acquired any of its capital stock nor issued any capital stock;
 
    (vi) the Company has not received notice that there has been a
  cancellation of an order for its products or a loss of a customer of the
  Company, the cancellation or loss of which would materially adversely
  affect the condition, financial or otherwise, assets, liabilities, business
  or results of operations of the Company;
 
    (vii) there has been no material change in the contingent obligations of
  the Company by way of guaranty, endorsement, indemnity, warranty or
  otherwise;
 
    (viii) there have been no loans made by the Company to its employees,
  officers or directors, other than travel advances and other advances made
  in the ordinary course of business;
 
    (ix) to the Company's knowledge there has been no waiver or compromise by
  the Company of a material right or of a material debt owed to it;
 
    (x) the Company has not made or agreed to make any disbursements or
  payments of any kind to any member or members of its Board of Directors;
 
    (xi) there have been no capital expenditures by the Company in excess of
  Fifty Thousand Dollars ($50,000) in the aggregate;
 
    (xii) there has been no change in accounting methods or practices
  (including without limitation, any change in depreciation or amortization
  policies or rates) by the Company;
 
    (xiii) there has been no revaluation by the Company of any of the assets
  or properties of the Company;
 
    (xiv) there has been no sale or transfer of any of the assets or
  properties of the Company, except in the ordinary course of business;
 
    (xv) there has been no loan by the Company to any person or entity;
 
    (xvi) there has been no commencement or notice of threat of commencement
  of any governmental proceeding against or investigation of the Company or
  its affairs;
 
    (xvii) there has been no revocation of license or right to do business
  granted to the Company;
 
                                      C-8

    (xviii) the Company has not paid any obligation or liability (fixed,
  contingent or otherwise) or discharged or satisfied any lien, or settled
  any liability, claim, dispute, proceeding, suit or appeal pending or
  threatened against it, except for current liabilities incurred in the
  ordinary course of business; and
 
    (xix) there has been no agreement or commitment by the Company to do or
  perform any of the acts described in this Section 3.6.
 
  3.7 Personal Property. The Company has good title, free and clear of all
title defects, objections and liens, including without limitation, leases,
chattel mortgages, conditional sales contracts, collateral security
arrangements and other title or interest-retaining arrangements, to all of its
machinery, equipment, furniture, inventory and other personal property. All
such personal property is in operable condition. All of the leases to personal
property utilized in the business of the Company are valid and enforceable by
the Company and neither the Company nor, to the Company's knowledge any other
party, is in material default under any such lease.
 
  3.8 Real Property. The Company does not own any real property. Section 3.8
of the Disclosure Statement of the Company contains a list of all leases for
real property to which the Company is a party, the square footage leased with
respect to each lease and the expiration date of each lease. All such leases
are valid and enforceable by the Company and neither the Company nor, to the
Company's knowledge any other party, is in material default under any such
lease. The real property owned, leased or occupied by the Company, the
improvements located thereon, and the furniture, fixtures and equipment
relating thereto (including plumbing, heating, air conditioning and electrical
systems), conform to any and all applicable health, fire, safety, zoning, land
use and building laws, ordinances and regulations. There are no outstanding
contracts made by the Company for any improvements made to the real property
owned, leased or occupied by the Company that have not been paid for.
 
  3.9 Patents, Trademarks, Trade Names and Copyrights. All patents,
trademarks, trade names, copyrights, processes, designs, formulas, inventions,
trade secrets, know-how, technology or other proprietary rights which are used
by the Company and material to the Company's operations, or proposed to be
used by the Company and that would be material to the Company's operations,
are owned or are licensed by the Company. The conduct of any business
conducted by the Company does not, to the Company's knowledge, infringe any
patent, trademark, trade name, copyright, trade secret, or other proprietary
right of any other person. No litigation is pending or, to the knowledge of
the Company, has been threatened against the Company or any officer, director
or employee of the Company, or to the Company's knowledge, any stockholder or
agent of the Company, for the infringement of any patents, trademarks or trade
names of any other party or for the misuse or misappropriation of any trade
secret, know-how or other proprietary right owned by any other party nor, to
the best knowledge of the Company, does any basis exist for such litigation.
To the best of the Company's knowledge, there has been no infringement or
unauthorized use by any other party of any patent, trademark, trade name,
copyright, process, design, formula, invention, trade secret, know-how,
technology or other proprietary right belonging to the Company. Each license
set forth in Section 3.9 of the Disclosure Statement is valid and enforceable
in accordance with its terms and is not the subject of any notice of
termination or nonrenewal. The Company has taken reasonable and practicable
steps designed to safeguard and maintain the secrecy and confidentiality of,
and its proprietary rights in, any patent, trademark, trade name, copyright,
process, design, formula, invention, trade secret, know-how or technology, of
which it owns or has a right to use.
 
  3.10 Litigation. Neither the Company nor any officer, director, stockholder,
employee or agent of the Company is a party to any pending or, to the
Company's knowledge, threatened action, suit, proceeding or investigation, at
law or in equity or otherwise in, for or by any court or other governmental
body which could have a material adverse effect on: (i) the financial
condition, or results of operations of the Company; or (ii) the transactions
contemplated by this Agreement. The Company is not and has not been subject to
any pending or, to its knowledge, threatened product liability claim; nor, to
its knowledge, does any basis exist for any such claim. The Company is not
subject to any decree, judgment, or order, of any court or other governmental
body of which it has knowledge which is reasonably likely to have a material
adverse effect on the financial condition or results of operations of the
Company or which could prevent the transactions contemplated by this
Agreement.
 
                                      C-9

  3.11 Protection of Intangible Property. Each employee and consultant of the
Company who has worked on or contributed to the development of the Company's
technology, trade secrets and other proprietary rights, executed a proprietary
rights and information agreement in the form attached to the Disclosure
Statement. The Company's trade secrets have not been used, distributed or
otherwise commercially exploited under circumstances which have caused, or
with the passage of time could cause, the loss of copyright or trade secret
status.
 
  3.12 Personnel. Section 3.12 of the Disclosure Statement of the Company
contains a list of: (i) all employment, bonus, profit sharing, percentage
compensation, employee benefit plans, incentive plans, pension or retirement
plans, stock purchase and stock option plans, oral or written contracts or
agreements with directors, officers, employees or unions, or consulting
agreements, to which the Company is a party or is subject as of the date of
this Agreement; and (ii) all group insurance programs in effect for employees
of the Company. The Company is not in default with respect to any of the
obligations so listed. The Company has delivered complete and correct copies
of all such obligations (to the extent they are in writing or written
descriptions to the extent they are oral) to the other Company. The Company
has no union contracts or collective bargaining agreements with, or any other
obligations to, employee organizations or groups relating to the Company's
business, nor is the Company currently engaged in any labor negotiations
except in minor grievances not involving any employee organization or group,
nor, to the knowledge of the Company, is the Company the subject of any union
organization affecting its business. There is no pending or, to the Company's
knowledge, threatened labor dispute, strike or work stoppage affecting the
Company's business. All plans described in Section 3.12 of the Disclosure
Statement are in full compliance with applicable provisions of the Employees
Retirement Income Security Act of 1974 ("ERISA") and regulations issued under
ERISA, and there is no unfunded liability with respect to such plans. Section
3.12 of the Disclosure Statement also lists the amount payable to employees of
the Company under other fringe benefit plans.
 
  3.13 Insurance. The insurance coverage maintained by the Company is adequate
for the conduct of the business of the Company.
 
  3.14 Certain Payments. To the knowledge of the Company, neither the Company,
nor any stockholder, director, officer, employee or agent of the Company, has
made or caused to be made, directly or indirectly, the payment of any
consideration whatsoever to any public official, candidate for public office,
political party, or other third person in connection with the business or
operations of the Company, or pertaining to the Company's relations with any
customer, supplier, or creditor, in contravention of the law of any applicable
jurisdiction.
 
  3.15 Brokers and Finders. Neither the Company nor any stockholder, director,
officer, employee or agent of the Company has retained any broker, finder or
investment banker in connection with the transactions contemplated by this
Agreement, except as set forth in Section 11.2. The Company will indemnify and
hold the other Company harmless against all claims for brokers', finders' or
investment bankers' fees made or asserted by any party claiming to have been
employed by the Company or any stockholder, director, officer, employee or
agent of the Company and all costs and expenses (including the reasonable fees
of counsel) of investigating and defending such claims.
 
  3.16 Contracts. Section 3.16 of the Disclosure Statement lists all oral or
written agreements, notes, instruments, or contracts to which the Company is a
party or by which its assets or properties may be bound which involve the
payment or receipt of more than Fifty Thousand Dollars ($50,000) (on an annual
basis), or which have a term of more than two years, or which involve
intellectual property, or which are employment or consulting agreements other
than those terminable at will (the "Contracts"). The Company is not in
material default in performance of its obligations under any such Contracts.
The Company has no knowledge of any material violation of any Contract by any
other party thereto and has no knowledge of any intent by any other party to a
Contract not to perform its obligations under such Contract.
 
  3.17 Stockholders and Employees. Except as set forth in Section 3.16 of the
Disclosure Statement, none of the stockholders, directors or management
personnel of the Company is presently a party to any transaction
 
                                     C-10

with the Company, including without limitation, any contract, agreement or
other arrangement: (i) providing for the furnishing of services to or by; (ii)
providing for rental of real or personal property to or from; or
(iii) otherwise requiring payments to or from, any stockholder, director or
management personnel, or any member of the family of any stockholder, director
or management personnel or any corporation, trust or other entity in which any
stockholder, director or management personnel has a substantial interest or is
an officer, director, investor or partner.
 
  3.18 Absence of Environmental Liabilities. The Company has, and to the
Company's knowledge, all previous owners, lessees and occupants of real
property leased by the Company have complied with all applicable environmental
laws, orders, regulations, rules and ordinances adopted, imposed or
promulgated by any governmental or regulatory entity relating to such real
property. The Company is not in violation of any federal, state or local law,
ordinance or regulation relating to industrial hygiene, worker safety,
environmental hazardous materials or waste or toxic materials on, under or
about such real property, including soil and waste water conditions. No
current use of the real property leased by the Company constitutes a public or
private nuisance. The environmental licenses, permits, clearances, covenants
and authorizations material to the operation of the Company are in full force
and effect. Any handling, transportation, storage, treatment or use of
Hazardous Material (as defined below) by the Company or, to the Company's
knowledge, all previous owners, lessees and occupants of real property leased
by the Company, has been in compliance with all laws, regulations and orders
relating to Hazardous Material. As used herein, the term "Hazardous Material"
means any hazardous or toxic substance, material or waste which is or becomes
regulated by any local government authority, the State of California, any
other state or the United States Government.
 
  3.19 Power of Attorney; Suretyships. The Company has no power of attorney
outstanding, nor has any obligation or liability, either actual, accrued,
accruing or contingent, as guarantor, surety, cosigner, endorser, co-maker,
indemnitor or otherwise in respect of the obligation of any other person,
corporation, partnership, joint venture, association, organization or other
entity.
 
  3.20 Business Practices. The Company has not made, offered or agreed to
offer anything of value to any government official, political party or
candidate for government office nor has it taken any action which would cause
it to be in violation of the Foreign Corrupt Practices Act of 1977.
 
  3.21 Accuracy of Documents and Information. The copies of all instruments,
agreements, other documents and written information set forth as, or
referenced in, schedules or exhibits to this Agreement or specifically
required to be furnished pursuant to this Agreement by the Company to the
other Company, including, without limitation, the Disclosure Statement of the
Company, are and will be complete and correct in all material respects. All
information in the Disclosure Statement of the Company is as of the date
hereof or such earlier date as is specified therein, which in no case is
before June 30, 1997 and there have been no material changes in the
information set forth therein between the date so specified and the date of
this Agreement. No representations or warranties made by the Company in this
Agreement, nor any document, written information, statement, financial
statement, certificate, schedule or exhibit furnished directly to the other
party hereto pursuant to this Agreement or in the Disclosure Statement of the
Company contains any untrue statement of a material fact. There is no fact
which materially and adversely affects the Company, its financial position,
assets, liabilities, business or results of operations known to the Company
which has not been expressly and fully set forth in (i) with respect to Ansan,
the S-4 and the Proxy Statement and (ii) with respect to Discovery and ATI,
information provided to Ansan in writing expressly for inclusion in the Proxy
Statement or the S-4.
 
                                     C-11

                                  ARTICLE IV
 
                  REPRESENTATIONS AND WARRANTIES OF DISCOVERY
 
  Discovery hereby represents and warrants to Ansan that, except as set forth
in the Disclosure Statement of Discovery:
 
  4.1 Capitalization of Discovery. The authorized capital stock of Discovery
is 10,000,000 shares of Preferred Stock, of which 2,200,256 shares are issued
and outstanding, and 50,000,000 shares of Common Stock, of which 6,712,256
shares are issued and outstanding. The outstanding shares of Preferred Stock
of Discovery are convertible into 8,801,024 shares of Discovery Common at the
conversion price currently in effect with respect thereto. All such issued and
outstanding shares have been duly authorized and validly issued, and are fully
paid and non-assessable. Discovery has outstanding options and warrants to
purchase 906,943 shares of Discovery Common Stock and 220,026 shares of
Discovery Preferred Stock pursuant to the Discovery Options and Discovery
Warrants and a list of such Discovery Options and Discovery Warrants
(including the exercise prices thereunder) is included in Schedule 4.1 of the
Disclosure Statement of Discovery. Except as set forth in the preceding
sentence, there are no outstanding warrants, options, agreements, convertible
or exchangeable securities (other than the Preferred Stock described above) or
other commitments pursuant to which Discovery is or may become obligated to
issue, sell, purchase, retire or redeem any shares of capital stock or other
securities.
 
  4.2 Capitalization of ATI. The authorized capital stock of ATI is 1,000,000
shares of Preferred Stock, of which 602,200 shares are issued and outstanding,
and 2,000,000 shares of Common Stock, of which 200,000 shares are issued and
outstanding. The outstanding shares of Convertible Preferred Stock of ATI are
convertible into 600,000 shares of ATI Common Stock. All such issued and
outstanding shares have been duly authorized and validly issued, and are fully
paid and non-assessable. ATI has outstanding options and warrants to purchase
200,000 shares of ATI Common Stock and no shares of ATI Preferred Stock and a
list of such options and warrants (including the exercise prices thereunder)
is included in Section 4.2 of the Disclosure Statement of Discovery. Except as
set forth in the preceding sentence, there are no outstanding warrants,
options, agreements, convertible or exchangeable securities (other than the
Preferred Stock described above) or other commitments pursuant to which ATI is
or may become obligated to issue, sell, purchase, retire or redeem any shares
of capital stock or other securities.
 
  4.3 Financial Statements. Discovery has delivered the following financial
statements (the "Discovery Financial Statements") to Ansan: Audited
Consolidated Balance Sheet of Discovery dated as of December 31, 1996,
together with Audited Consolidated Statements of Operations, Consolidated
Stockholders' Equity and Consolidated Changes in Cash Flow during the year
ended December 31, 1996; and Unaudited Consolidated Balance Sheet of Discovery
dated as of March 31, 1997, together with Unaudited Consolidated Statements of
Operations, Stockholders' Equity and Changes in Cash Flows for the three
months then ended. Each Discovery Financial Statement together with the notes
thereto is in accordance with the books and records of Discovery, fairly
presents the consolidated financial position of Discovery and ATI and the
consolidated results of operations of Discovery and ATI for the period
indicated, and has been prepared in accordance with generally accepted
accounting principles consistently applied.
 
  4.4 Absence of Undisclosed Liabilities. As of March 31, 1997 neither
Discovery nor ATI had any indebtedness or liability (absolute or contingent)
which are not shown or provided for in full on the Balance Sheet dated March
31, 1997 included in the Discovery Financial Statements. Except as set forth
in the Balance Sheet dated March 31, 1997 included in the Discovery Financial
Statements, Discovery and ATI do not have outstanding on the date hereof, nor
will they have outstanding on the Closing Date, any indebtedness or liability
(absolute or contingent) other than those incurred since March 31, 1997 in the
ordinary course of business which are not material to the operations of
Discovery and ATI.
 
  4.5 Compliance With Law. Section 4.5 of the Disclosure Statement of
Discovery contains a true and complete list of all licenses, permits and
authorizations necessary for the lawful conduct of Discovery's and ATI's
businesses wherever conducted pursuant to all applicable statutes, laws,
ordinances, rules and regulations
 
                                     C-12

of all governmental bodies, agencies and subdivisions having, asserting or
claiming jurisdiction over Discovery or ATI or over any part of their
operations.
 
  4.6 Patents, Trademarks and Trade Names. Section 4.6 of the Disclosure
Statement of Discovery sets forth a list of all patents, patent applications,
trademarks, registered and unregistered, and trade names, registered and
unregistered, owned by Discovery and ATI.
 
  4.7 Employees. Section 4.7 of the Disclosure Statement of Discovery contains
a list of the names, current salary rates, bonuses paid during the last fiscal
year, and accrued vacation and sick leave for all the employees of Discovery
and ATI as of June 30, 1997.
 
  4.8 Insurance. Section 4.8 of the Disclosure Statement of Discovery contains
a list of all insurance policies and bonds in force with respect to Discovery
and ATI showing for each such policy or bond: (i) the owner; (ii) the coverage
of such policy or bond; (iii) the amount of premium properly allocable to such
policy or bond; (iv) the name of the insurer; and (v) the termination date of
the policy or bond. Copies of all such insurance policies and bonds have been
furnished to Ansan. All such insurance policies and bonds are in full force
and effect.
 
  4.9 Bank Accounts. Section 4.9 of the Disclosure Statement of Discovery
contains a list of all bank accounts of Discovery and ATI, identifying the
name of the bank, the account number, and the authorized signatories to the
account.
 
  4.10 ATI. Section 3.4 of the Disclosure Statement of Discovery sets forth
Discovery's percentage ownership of the outstanding capital stock of ATI. Such
stock is free and clear of any liens and encumbrances and is not subject to
any preemptive rights or right of first refusal.
 
  4.11 Proxy Statement and S-4. Discovery shall provide all information
related to Discovery and ATI and their respective officers, directors and
stockholders reasonably requested by Ansan for inclusion in the Proxy
Statement and S-4, including all amendments and supplements related thereto to
the extent such information is within Discovery's possession or reasonably
accessible by Discovery. None of such information shall contain any untrue
statement of a material fact or omit to state any material fact required to be
stated therein or necessary in order to make the statements therein, in light
of the written information previously provided by Discovery expressly for
inclusion in the Proxy Statement and S-4 (to the extent not superseded) and in
light of the other circumstances under which they are made, not misleading. If
requested by Ansan, Discovery shall confirm from time to time that as of the
date of such request the information previously provided by Discovery to Ansan
for the express purpose of inclusion in the Proxy Statement or S-4, including
any amendments or supplements thereto, continues to be true and correct in all
material respects and does not omit to state any material fact necessary to
make such information not misleading.
 
                                   ARTICLE V
 
                    REPRESENTATIONS AND WARRANTIES OF ANSAN
 
  Ansan hereby represents and warrants to Discovery that, except as set forth
in the Officer-Certified Disclosure Statement of Ansan:
 
  5.1 Capitalization. The authorized capital stock of Ansan is 5,000,000
shares of Ansan Preferred Stock, none of which are issued and outstanding, and
20,000,000 shares of Ansan Common Stock, of which 2,851,954 are issued and
outstanding. All such issued and outstanding shares have been duly authorized
and validly issued, and are fully paid and non-assessable. Ansan has
outstanding options to purchase 355,377 shares of Ansan Common Stock pursuant
to its existing plans and has reserved an additional 19,623 shares of Ansan
Common Stock for issuance under such plans. Ansan has outstanding Class A
Warrants and Class B Warrants exercisable for 2,207,500 shares of Ansan Common
Stock and 3,702,500 shares of Ansan Common Stock, respectively.
 
                                     C-13

Ansan has outstanding underwriters' options to purchase 520,000 shares of
Ansan Common Stock. A list of all outstanding options and warrants, and the
exercise prices thereunder, is set forth in Section 5.1 of the Disclosure
Statement of Ansan. Except as set forth in this Section 5.1 of the Agreement,
there are no outstanding warrants, options, agreements, convertible or
exchangeable securities or other commitments pursuant to which Ansan is or may
become obligated to issue, sell, purchase, retire or redeem any shares of
capital stock or other securities.
 
  5.2 Financial Statements. Ansan has delivered the following consolidated
financial statements of Ansan ("Ansan Financial Statements") to Discovery:
Audited Balance Sheets of Ansan dated as of December 31, 1996, together with
audited Statements of Operations, Stockholders' Equity and Changes in Cash
Flow during the three years ended December 31, 1996 included in Ansan's Annual
Report on Form 10-K filed with the SEC for the year ended December 31, 1996
and unaudited Balance Sheets of Ansan together with Statements of Operations,
and Changes in Cash Flow for the three months ended March 31, 1997 included in
Ansan's Quarterly Report on Form 10-Q. Each Ansan Financial Statement together
with the notes thereto is in accordance with the books and records of Ansan,
fairly presents the financial position of Ansan and the results of operations
of Ansan for the period indicated, and has been prepared in accordance with
generally accepted accounting principles consistently applied.
 
  5.3 Absence of Undisclosed Liabilities. As of March 31, 1997, Ansan had no
indebtedness or liability (absolute or contingent) which is not shown or
provided for in full on the Balance Sheet dated March 31, 1997 included in the
Ansan Financial Statements. Except as set forth in the Balance Sheet dated
March 31, 1997 included in Ansan Financial Statements, Ansan does not have
outstanding on the date hereof, nor will it have outstanding on the Closing
Date, any indebtedness or liability (absolute or contingent) other than those
incurred since March 31, 1997 in the ordinary course of business which are not
material to the operations of Ansan.
 
  5.4 Shares Issued in Connection With the Merger. The Ansan Stock to be
issued to the Holders pursuant to the Merger, when issued in accordance with
this Agreement and the Certificate of Merger, will be duly authorized, validly
issued, fully paid and non-assessable. The shares of Ansan Stock to be issued
to the holders of Discovery Options and Discovery Warrants upon exercise of
Discovery Options and Discovery Warrants after the Merger, when issued upon
exercise of Discovery Options and Discovery Warrants assumed by Ansan in
accordance with this Agreement and the Certificate of Merger, will be duly
authorized, validly issued, fully paid and non-assessable. The agreements
evidencing the Discovery Options and Discovery Warrants, upon assumption by
Ansan on the Effective Date pursuant to Section 2.3.1 of this Agreement, will
constitute legal, valid and binding obligations of Ansan, enforceable against
Ansan in accordance with their terms, subject as to enforcement: (i) to
bankruptcy, insolvency, reorganization, arrangement, moratorium and other laws
of general applicability relating to or affecting creditors' rights; and (ii)
to general principles of equity, whether such enforcement is considered in a
proceeding in equity or at law.
 
  5.5 Compliance With Law. Section 5.5 of the Disclosure Statement of Ansan
contains a true and complete list of all licenses, permits and authorizations
necessary for the lawful conduct of Ansan's business wherever conducted
pursuant to all applicable statutes, laws, ordinances, rules and regulations
of all governmental bodies, agencies and subdivisions having, asserting or
claiming jurisdiction over Ansan or over any part of its operations.
 
  5.6 Patents, Trademarks and Trade Names. Section 5.6 of the Disclosure
Statement of Ansan sets forth a list of all patents, patent applications,
trademarks, registered and unregistered, and trade names, registered and
unregistered, owned by Ansan.
 
  5.7 Exchange Act Filings. All reports, schedules and statements (including
all exhibits and schedules thereto and all documents incorporated by reference
therein) required to be filed by Ansan within the year prior to the date of
this Agreement under the Exchange Act, copies of which have been furnished to
Discovery, have been duly filed, were in substantial compliance with the
requirements of their respective forms, and were complete and correct in all
material respects as of the dates at which the information was furnished. As
of the date of filing, no such report contained any untrue statement of a
material fact or omitted to state a material fact necessary in order to make
the statements made therein, in light of the circumstances under which they
were made, not misleading.
 
                                     C-14

  5.8 Employees. Section 5.8 of the Disclosure Statement of Ansan contains a
list of the names, current salary rates, bonuses paid during the last fiscal
year, and accrued vacation and sick leave for all the employees of Ansan as of
June 30, 1997.
 
  5.9 Insurance. Section 5.9 of the Disclosure Statement of Ansan contains a
list of all insurance policies and bonds in force with respect to Ansan
showing for each such policy or bond: (i) the owner; (ii) the coverage of such
policy or bond; (iii) the amount of premium properly allocable to such policy
or bond; (iv) the name of the insurer; and (v) the termination date of the
policy or bond. Copies of all such insurance policies and bonds have been
furnished to Discovery. All such insurance policies and bonds are in full
force and effect.
 
  5.10 Bank Accounts. Section 5.10 of the Disclosure Statement of Ansan
contains a list of all bank accounts of Ansan, identifying the name of the
bank, the account number, and the authorized signatories to the account.
 
  5.11 Proxy Statement and S-4. None of the information relating to Ansan or
its respective officers and directors included or incorporated by reference in
the Proxy Statement or the S-4 will, in the case of the Proxy Statement or any
amendments or supplements thereto, at the time of the mailing of the Proxy
Statement and any amendments or supplements thereto, and at the time of the
meeting of stockholders of the Company to vote upon this Agreement, the Merger
and related transactions, or, in the case of the S-4, at the time it becomes
effective under the 1933 Act and at the Effective Time, contain any untrue
statement of a material fact or omit to state any material fact required to be
stated therein or necessary in order to make the statements therein, in light
of the circumstances under which they are made, not misleading. The S-4 will
comply as to form with the 1933 Act and the rules and regulations thereunder.
The Proxy Statement will comply as to form in all material respects with the
provisions of the Exchange Act and the rules and regulations thereunder. If at
any time prior to the Effective Time any event with respect to Ansan, its
officers or directors should occur which is or is required to be described in
an amendment or a supplement to the Proxy Statement or the S-4 Ansan shall so
amend or supplement to Proxy Statement or the S-4.
 
                                  ARTICLE VI
 
                    CONDITIONS TO THE OBLIGATIONS OF ANSAN
 
  The obligations of Ansan to consummate the Merger is subject to the
fulfillment, at or before the Closing of all the following conditions, any one
or more of which may be waived by Ansan:
 
  6.1 Representations and Warranties True at Closing. The representations and
warranties of Discovery contained in this Agreement, except those set forth in
Section 3.6 of this Agreement, shall be deemed to have been made again at and
as of the Closing (including the update of the Disclosure Statement of
Discovery referred to in Section 8.1 of this Agreement) and shall be true in
all material respects.
 
  6.2 Covenants Performed. All of the obligations of Discovery to be performed
at or before the Closing pursuant to the terms of this Agreement shall have
been duly performed in all material respects.
 
  6.3 Certificate. At the Closing, Ansan shall have received a certificate
signed by the President of Discovery to the effect that the conditions set
forth in Sections 6.1, 6.2 and 6.14 have been satisfied.
 
  6.4 Stockholder Approval. This Agreement and the Certificate of Merger shall
have been duly approved by the stockholders of Discovery and Ansan.
 
  6.5 Titan. Titan shall have executed the Titan Agreement with Ansan. All
Ansan Stock owned by Titan shall be repurchased and all indebtedness, except
for $100,000, owing by Ansan to Titan shall be retired, in accordance with the
Titan Agreement.
 
                                     C-15

  6.6 Appraisal Shares. The aggregate number of Appraisal Shares with respect
to each of Ansan and Discovery shall not exceed five (5%) percent of the
aggregate Ansan Stock outstanding immediately prior to the Merger or the
aggregate Discovery Stock outstanding immediately prior to the Merger, as the
case may be.
 
  6.7 Tax-Free Reorganization. Ansan shall have received the opinion of its
counsel to the effect that the Merger will constitute a tax-free
reorganization within the meaning of Section 368(a) of the Code, which opinion
shall be substantially similar to the opinion delivered to Discovery pursuant
to Section 7.5. In preparing the tax opinion, counsel may rely upon (and to
the extent reasonably required, the parties shall make and use their best
efforts to cause their directors and stockholders to make) reasonable
representations relating thereto.
 
  6.8 Nasdaq Approval. Ansan and Discovery, on a pro-forma basis, shall
satisfy the applicable and proposed initial listing requirements for the
Nasdaq SmallCap Market and Ansan shall be approved by Nasdaq for listing its
Common Stock on the Nasdaq SmallCap Market immediately following the Merger.
The shares of Ansan Common Stock to be issued in the Merger and upon
conversion of the Ansan Preferred Stock (including Ansan Preferred Stock to be
issued upon exercise of Ansan warrants to be issued to Discovery
securityholders in connection with the Merger) and the exercise of Ansan
options and Ansan warrants to be issued to Discovery securityholders in
connection with the Merger shall have been listed on the Nasdaq SmallCap
Market. There shall be no proceedings pending or threatened by Nasdaq that are
reasonably likely to result in the delisting of the Ansan Common Stock from
the Nasdaq SmallCap Market.
 
  6.9 Affiliates Agreements. Discovery shall have delivered to Ansan a letter
identifying all persons who are Affiliates of Discovery, and each such
Affiliate shall have executed and delivered an Affiliates Agreement to Ansan
in the form and subject to the restrictions provided in Exhibit 6.9.
 
  6.10 Lockup Agreements. Discovery stockholders holding 85% or more of the
outstanding securities of Discovery shall have executed and delivered a Lockup
Agreement in the form and subject to the restrictions provided in Exhibits
6.10A or 6.10B, as applicable.
 
  6.11 Fairness Opinion. The Board of Directors of Ansan shall have received
an opinion, dated on or before the date hereof from Dakin Securities that the
terms of the Merger as contemplated by this Agreement are fair to the
stockholders of Ansan, which opinion shall be in form and substance reasonably
satisfactory to Ansan.
 
  6.12 The S-4 shall have become effective under the 1933 Act and shall not be
the subject of any stop order or proceedings seeking a stop order and the
Proxy Statement shall on the Closing Date not be subject to any proceeding
commenced or threatened by the SEC.
 
  6.13 Certificate of Merger. The Certificate of Merger shall have been filed
with the Secretary of State of the State of Delaware.
 
  6.14 Material Changes in the Business of Discovery and ATI. There shall have
been no material adverse change in the business of Discovery or ATI, provided
that insofar as solely the financial condition (including without limitation
the assets, liabilities and results of operations) of Discovery and ATI are
concerned, no such material adverse change shall be deemed to have occurred so
long as Discovery Working Capital is at least $5,000,000.
 
  6.15 No Action to Prevent Completion. Ansan shall not have determined, in
the reasonable exercise of its discretion, that the transactions contemplated
by this Agreement have become inadvisable or impractical by reason of the
institution of litigation or other proceedings with respect to or affecting
the transactions contemplated by this Agreement.
 
  6.16 Consents. Ansan shall have received in writing all consents, approvals,
and waivers required in connection with the Merger (a) from parties to
Discovery's agreements, indentures, mortgages, franchises, licenses, permits,
leases, and other instruments set forth in Section 3.16 of the Disclosure
Statement of Discovery, and (b) from all governmental authorities, except to
the extent that the failure to receive any such consent would
 
                                     C-16

not reasonably be expected to have a material adverse effect on the business
of the corporation surviving the Merger.
 
  6.17 Ansan Board. Effective as of the Effective Time, all action shall have
been taken so that the Ansan Board shall consist of seven members designated
by Discovery, two members designated by Ansan and one member designated by D.
H. Blair & Co.
 
  6.18 Documentation. All actions, proceedings, instruments, resolutions,
certificates, and documents reasonably requested by Ansan to be executed and
delivered to Ansan in order to carry out this Agreement and to consummate the
Merger, and all of the relevant legal matters, shall be reasonably
satisfactory to Ansan and its counsel.
 
  6.19 Liquidation Preference. Ansan shall be reasonably satisfied (through
the receipt of stockholder waivers to the extent reasonably required) that the
consummation of the Merger will not confer upon preferred stockholders of
Discovery or ATI the right to a distribution of the liquidation preference
afforded to such stockholders.
 
  6.20 Legal Opinion of Discovery Counsel. Ansan shall receive an opinion
dated the Closing Date of Roberts, Sheridan & Kotel, a professional
corporation, counsel to Discovery and ATI, in substantially the form attached
hereto as Exhibit 6.20.
 
  6.21 Discovery Working Capital. As of the Closing Date, Discovery Working
Capital shall be no less than $5,000,000.
 
                                  ARTICLE VII
 
                  CONDITIONS TO THE OBLIGATIONS OF DISCOVERY
 
  The obligations of Discovery to consummate the Merger are subject to the
fulfillment, at or before the Closing, of all of the following conditions, any
one or more of which may be waived by Discovery:
 
  7.1 Representations and Warranties True at Closing. The representations and
warranties of Ansan contained in this Agreement, except for those in Section
3.6 of this Agreement, shall be deemed to have been made again at and as of
the Closing (including the update of the Disclosure Statement of Ansan
referred to in Section 8.1 of this Agreement) and shall be true in all
material respects.
 
  7.2 Covenants Performed. All of the obligations of Ansan to be performed at
or before the Closing pursuant to the terms of this Agreement shall have been
duly performed in all material respects.
 
  7.3 Certificate. At the Closing, Discovery shall have received a certificate
signed by the President of Ansan to the effect that the conditions set forth
in Sections 7.1, 7.2 and 7.10 have been satisfied.
 
  7.4 Stockholder Approval. This Agreement and the Certificate of Merger shall
have been duly approved by the stockholders of Ansan and Discovery.
 
  7.5 Tax-Free Reorganization. Discovery shall have received the opinion of
its counsel to the effect that the Merger will constitute a tax-free
reorganization within the meaning of Section 368(a) of the Code, which opinion
shall be substantially similar to the opinion delivered to Ansan pursuant to
Section 6.7. In preparing the tax opinion, counsel may rely upon (and to the
extent reasonably required, the parties shall make and use their reasonable
best efforts to cause their directors and stockholders to make) reasonable
representations relating thereto.
 
  7.6 Nasdaq Approval. Ansan and Discovery, on a pro-forma basis, shall
satisfy the applicable and proposed initial listing requirements for the
Nasdaq SmallCap Market and Ansan shall be approved by Nasdaq for listing its
Common Stock on the Nasdaq SmallCap Market immediately following the Merger.
The shares of Ansan Common Stock to be issued in the Merger and upon
conversion of the Ansan Preferred Stock (including
 
                                     C-17

Ansan Preferred Stock to be issued upon exercise of Ansan warrants to be
issued to Discovery securityholders in connection with the Merger) and the
exercise of Ansan Options and Ansan Warrants to be issued to Discovery
security holders in connection with the Merger shall have been listed on the
Nasdaq SmallCap Market. There shall be no proceedings pending or threatened by
Nasdaq that are reasonably likely to result in the delisting of the Common
Stock of Ansan from the Nasdaq SmallCap Market.
 
  7.7 Titan. Titan shall have executed the Titan Agreement with Ansan. All
Ansan Stock owned by Titan shall be repurchased and all indebtedness, except
for $100,000, owing by Ansan to Titan shall be retired, in accordance with the
Titan Agreement.
 
  7.8 The S-4 shall have become effective under the 1933 Act and shall not be
the subject of any stop order or proceedings seeking a stop order and the
Proxy Statement shall on the Closing not be subject to any proceeding
commenced or threatened by the SEC.
 
  7.9 Certificate of Merger. The Certificate of Merger shall have been filed
with the Secretary of State of the State of Delaware.
 
  7.10 Material Changes in the Business of Ansan. There shall have been no
material adverse change in the financial position, results of operations,
assets, liabilities or business of Ansan between the date of this Agreement
and the Closing; provided that such changes as are contemplated by the budget
included in Section 10.3 of the Disclosure Statement of Ansan shall not be
deemed material for the purposes of this Section 7.10.
 
  7.11 No Action to Prevent Completion. Discovery shall not have determined,
in the reasonable exercise of its discretion, that the transactions
contemplated by this Agreement have become inadvisable or impractical by
reason of the institution of litigation or other proceedings with respect to
or affecting the transactions contemplated by this Agreement.
 
  7.12 Consents. Discovery shall have received in writing all consents,
approvals, and waivers required in connection with the Merger (a) from parties
to Ansan's agreements, indentures, mortgages, franchises, licenses, permits,
leases, and other instruments set forth in Section 3.16 of the Disclosure
Statement of Ansan, and (b) from all governmental authorities, except to the
extent that the failure to receive any such consent would not reasonably be
expected to have a material adverse effect on the business of the corporation
surviving the Merger. Such consents shall include consent from Boehringer
Ingelheim, if required.
 
  7.13 Ansan Board. Effective as of the Effective Time, all action shall have
been taken so that the Ansan Board shall consist of seven members designated
by Discovery, two members designated by Ansan and one member designated by D.
H. Blair & Co.
 
  7.14 Documentation. All actions, proceedings, instruments, resolutions,
certificates, and documents reasonably requested by Discovery to be executed
and delivered to Discovery in order to carry out this Agreement and to
consummate the Merger, and all of the relevant legal matters, shall be
reasonably satisfactory to Discovery and its counsel.
 
  7.15 Legal Opinion of Ansan Counsel. Discovery shall receive an opinion
dated the Closing Date of Heller Ehrman White & McAuliffe, counsel to Ansan,
in substantially the form attached hereto as Exhibit 7.15.
 
  7.16 Fairness Opinion. The Board of Directors of Discovery shall have
received an opinion, dated no later than August 17, 1997, from a reputable and
independent investment banking firm that the terms of the Merger are fair to
the stockholders of Discovery, which opinion shall be in form and substance
reasonably satisfactory to Discovery.
 
  7.17 Appraisal Shares. The aggregate number of Appraisal Shares with respect
to each of Ansan and Discovery shall not exceed five (5%) percent of the
aggregate Ansan Stock outstanding immediately prior to the Merger or the
aggregate Discovery Stock outstanding immediately prior to the Merger, as the
case may be.
 
                                     C-18

                                 ARTICLE VIII
 
                             PRE-CLOSING COVENANTS
 
  During the period from the date of this Agreement until the Effective Time,
Ansan and Discovery (each sometimes referred to as a "Company" for the
purposes of this Article VIII) each covenants and agrees as follows:
 
  8.1 Advice of Changes. Each Company will promptly advise the other Company
in writing (i) of any event occurring subsequent to the date of this Agreement
that would render any representation or warranty of such Company contained in
this Agreement, if made on or as of the date of such event or the Closing
Date, untrue or inaccurate in any material respect, (ii) of any material
adverse change in such Company's financial position, results of operations,
assets, liabilities or business, and (iii) the occurrence of material
noncompliance with Sections 8.3.21 (in the case of Ansan) or 8.15 (in the case
of Discovery) of this Agreement. Not less than four days before the Closing,
each Company shall deliver to the other Company hereto an update of the
Disclosure Statement previously delivered by such Company, showing any changes
which have occurred with respect to the information contained therein since it
was originally issued and containing a description of any representation or
warranty in this Agreement which is no longer true as of such date.
 
  8.2 Maintenance of Business. Each Company will use its reasonable best
efforts to carry on and preserve its business and its relationships with
customers, suppliers, employees and others in substantially the same manner as
it has prior to the date hereof. If either Company becomes aware of a
deterioration in the relationship with any customer, supplier or key employee,
it will promptly bring such information to the attention of the other Company
in writing.
 
  8.3 Conduct of Business. Ansan will continue to conduct its business and use
reasonable efforts to maintain its business relationships in the ordinary and
usual course and, except as provided in this Agreement, will not, without the
prior written consent of Discovery:
 
    8.3.1 borrow any money;
 
    8.3.2 incur any liability except for those that may be incurred (i) in
  the ordinary course of business, consistent with past practice, and are not
  material in amount or (ii) in connection with the performance or
  consummation of this Agreement;
 
    8.3.3 encumber or permit to be encumbered any of its assets except in the
  ordinary course of its business consistent with past practice;
 
    8.3.4 dispose of any of its assets, except inventory in the ordinary
  course of business, consistent with past practice;
 
    8.3.5 enter into any material lease or contract for the purchase or sale
  of any property, real or personal, except in the ordinary course of
  business, consistent with past practice;
 
    8.3.6 fail to maintain its equipment and other assets in good working
  condition and repair according to the standards it has maintained such
  equipment and other assets to the date of this Agreement, subject only to
  ordinary wear and tear;
 
    8.3.7 pay any bonus, increased salary, or special remuneration to any
  officer, employee (other than those paid in the ordinary course of
  business, consistent with past practice) or consultant or enter into any
  new employment or consulting agreement with any such person, except in the
  ordinary course of business, consistent with past practice;
 
    8.3.8 change accounting methods;
 
    8.3.9 declare, set aside or pay any cash or stock dividend or other
  distribution in respect of capital stock, or redeem or otherwise acquire
  any of its capital stock (except pursuant to employee stock repurchase
  agreements upon termination of an employee consistent with its past
  practice);
 
                                     C-19

    8.3.10 amend or terminate any contract, agreement or license to which it
  is a party except those amended or terminated in the ordinary course of
  business consistent with past practice, and which are not material in
  amount;
 
    8.3.11 loan any amount to any person or entity, other than advances for
  travel and expenses which are incurred in the ordinary course of business
  consistent with past practice, not material in amount and documented by
  receipts for the claimed amounts;
 
    8.3.12 guarantee or act as a surety for any obligation except for the
  endorsement of checks and other negotiable instruments in the ordinary
  course of business, consistent with past practice, which are not material
  in amount;
 
    8.3.13 waive or release any material right or claim except in the
  ordinary course of business, consistent with past practice;
 
    8.3.14 issue or sell any shares of its capital stock of any class (except
  upon the exercise of an option currently outstanding, as disclosed in
  Section 4.1, 4.2 or 5.1, as the case may be, or granted in accordance with
  this Section 8.3.14), or any other of its securities, or issue or create
  any warrants, obligations, subscriptions, options, convertible securities,
  or other commitments to issue shares of capital stock without the prior
  written consent of the other party hereto, which consent shall not be
  withheld unreasonably if options are being granted for the purpose of
  recruiting new personnel in accordance with the past practices regarding
  the pricing, the total number of options granted, the options awarded in
  relation to the job title of the recipient and the timing of the option
  awards;
 
    8.3.15 accelerate the vesting of any outstanding options;
 
    8.3.16 split or combine the outstanding shares of its capital stock of
  any class or enter into any recapitalization affecting the number of
  outstanding shares of its capital stock of any class or affecting any other
  of its securities;
 
    8.3.17 merge, consolidate or reorganize with, or acquire any entity,
  except for the Merger;
 
    8.3.18 amend its Certificate of Incorporation or Bylaws, except as
  expressly contemplated by this Agreement;
 
    8.3.19 other than pursuant to the Titan Agreement, license any of its
  technology or intellectual property, except in the ordinary course of
  business;
 
    8.3.20 agree to do any of the things described in the preceding clauses
  8.3.1 through 8.3.19; or
 
    8.3.21 fail to conduct itself in material compliance with the budget of
  Ansan set forth on Section 10.3 to the Ansan Disclosure Statement.
 
  8.4 Stockholder Meetings. Each Company will use its reasonable best efforts
to submit this Agreement and related matters for approval of their
stockholders, which approval shall be recommended by each Company's Board of
Directors and management, subject to the fiduciary obligations of its
directors and officers.
 
  8.5 Proxy Statement. Ansan will send to its stockholders, for the purpose of
considering and voting upon the Merger, the Proxy Statement. Discovery shall
promptly provide to Ansan information in accordance with Sections 2.6 and 4.11
of this Agreement. Neither Company shall provide to its stockholders or
publish any material that violates the 1933 Act or Exchange Act with respect
to the transactions contemplated hereby.
 
  8.6 Regulatory Approvals. Prior to the Closing, each Company shall execute
and file, or join in the execution and filing, of any application or other
document that may be necessary in order to obtain the authorization, approval
or consent of any governmental body, federal, state, local or foreign which
may be reasonably required, or which the other Company may reasonably request,
in connection with the consummation of the transactions contemplated by this
Agreement. Each Company shall use reasonable commercial efforts to obtain all
such authorizations, approvals and consents.
 
                                     C-20

  8.7 Necessary Consents. Prior to the Closing, each Company will use
reasonable commercial efforts to obtain such written consents and take such
other actions as may be necessary or appropriate in addition to those set
forth in Section 8.6 to allow the consummation of the transactions
contemplated hereby and to allow such Company to carry on its business after
the Closing.
 
  8.8 Litigation. Prior to the Closing, each Company will notify the other
Company in writing promptly after learning of any material actions, suits,
proceedings or investigations by or before any court, board or governmental
agency, initiated by or against it or any of its Subsidiaries, or known by it
to be threatened against it or any of its Subsidiaries.
 
  8.9 Exclusivity. From the date hereof until the earlier of termination of
this Agreement or consummation of the Merger, neither Ansan nor Discovery nor
any of their officers, directors, employees, representatives (including any
investment banker, attorney or accountant retained by them), agents or
affiliates shall directly or indirectly encourage, solicit, initiate,
facilitate or conduct discussions or negotiations with, provide any
information to, or enter into any agreement with, any corporation,
partnership, person or other entity or group concerning or expressing an
interest in or proposing any merger, consolidation, reorganization, share
exchange, business combination, liquidation, dissolution sale of all or
significant assets or securities or other similar transaction involving Ansan
or Discovery, except to the extent required by their fiduciary duties as
determined by the Boards of Directors of Ansan or Discovery, as the case may
be, after discussion with their counsel.
 
  8.10 Due Diligence. Until the Closing, each Company shall provide the other
Company (including, subject to the receipt of any necessary confidentiality
undertakings, accounting, legal, and investment banking representatives) with
reasonable access to its offices and its senior employees for the purpose of
due diligence, in accordance with procedures established by the parties to
minimize disruptions of their businesses. Each party shall provide the other
party with all material documents requested in the course of performing due
diligence, including documents requested prior to execution of this Agreement,
within 30 days of such request.
 
  8.11 Satisfaction of Conditions Precedent. Subject to the fiduciary
obligations of its directors and officers, each Company will use its
commercially reasonable efforts to satisfy or cause to be satisfied all the
conditions precedent which are set forth in Section 6 and 7, and each Company
will use its commercially reasonable efforts to cause the transactions
contemplated by this Agreement to be consummated, and, without limiting the
generality of the foregoing, to obtain all consents and authorizations of
third parties and to make all filings with, and give all notices to, third
parties that may be necessary or reasonably required on its part in order to
effect the transactions contemplated hereby.
 
  8.12 Representations Regarding Tax Matters. Each Company, its officers,
directors, and stockholders, will make such representations as are reasonably
requested by counsel to both parties in order that such counsel may render the
tax opinions required by Sections 6.7 and 7.5 hereof.
 
  8.13 Notification of Customers, Suppliers and Employees. Prior to the
Closing, Discovery will notify each customer, supplier of products and
employee who is material to Discovery's business of the basic facts relating
to the transactions contemplated by this Agreement.
 
  8.14 Fairness Opinion. Discovery shall use commercially reasonable efforts
to satisfy the condition set forth in Section 7.16.
 
  8.15 Discovery Working Capital. Through the Closing Date, Discovery shall
use its best commercial efforts to maintain Discovery Working Capital of at
least $5,000,000.
 
                                  ARTICLE IX
 
                  CONFIDENTIALITY COVENANT AND ANNOUNCEMENTS
 
  9.1 Confidentiality. Neither party to this Agreement shall use or disclose
any non-public information obtained from the other party for any purpose
unrelated to the Merger, and, if this Agreement is terminated for
 
                                     C-21

any reason whatsoever, each party shall return to the other or destroy all
originals and copies of all documents and papers containing technical,
financial, and other information furnished to such party pursuant to this
Agreement or during the negotiations which preceded this Agreement, and shall
neither use nor disclose any such information except to the extent that such
information is available to the public, is rightfully obtained from third
parties or is independently developed or is required to be disclosed by law or
legal process.
 
  9.2 Announcements. Neither party to this Agreement shall issue a press
release or other public communication relating to this Agreement, the
Certificate of Merger or the Merger without the prior approval of the other
party. Notwithstanding the foregoing, (i) Ansan may make such announcements
regarding the Merger as, in the judgment of its management after consultation
with legal counsel, are necessary to comply with securities laws or Nasdaq
regulations (provided that Discover shall be afforded a reasonable opportunity
to review the same), and (ii) Discovery may communicate with its stockholders
regarding the foregoing matters.
 
                                   ARTICLE X
 
                                  TERMINATION
 
  10.1 Mutual Agreement. This Agreement may be terminated at any time prior to
the Effective Time by the consent of Ansan and Discovery, even if and after
the stockholders of Discovery and Ansan have approved this Agreement and the
Certificate of Merger.
 
  10.2 Termination by Ansan. This Agreement may be terminated by Ansan alone,
by means of written notice to Discovery if (a) Discovery fails to perform any
material covenant of Discovery contained in this Agreement, or (b) any of the
conditions set forth in Article VI of this Agreement shall not have been
satisfied by December 31, 1997, or shall have become incapable of being
satisfied by Discovery unless waived by Ansan.
 
  10.3 Termination by Discovery. This Agreement may be terminated by Discovery
alone, by means of written notice to Ansan if (a) Ansan fails to perform any
material covenant of Ansan contained in this Agreement or (b) any of the
conditions set forth in Article VII of this Agreement shall not have been
satisfied by December 31, 1997, or shall have become incapable of being
satisfied by Ansan unless waived by Discovery, (c) Ansan fails to comply in
any material respect with the operating budget dated as of the date hereof and
included as Section 10.3 to the Disclosure Statement of Ansan, or (d) if
before August 17, 1997, the conditions set forth in Section 7.16 has not been
satisfied provided Discovery has complied with Section 8.14, which termination
must be elected, if at all, by Discovery by August 17, 1997.
 
  10.4 Limitation on Damages. In no event shall any party to this Agreement be
liable for any damages (including punitive and compensatory damages), costs or
expenses aggregating in excess of $3,500,000 arising under or related to
breaches or alleged breaches of this agreement and the transactions
contemplated hereby.
 
                                  ARTICLE XI
 
                                 MISCELLANEOUS
 
  11.1 Future Structure. Concurrent with the Effective Time, Ansan shall
change its name to a name mutually agreed-upon by both Ansan and Discovery.
 
  11.2 Expenses. Each of Ansan and Discovery shall pay its own costs and
expenses, including legal, accounting and investment banking fees and
expenses, relating to this Agreement, the negotiations leading up to this
Agreement and the transactions contemplated by this Agreement. Ansan
represents and warrants that it has not used any broker, finder or financial
advisor in connection with the Merger other than Dakin Securities Corporation.
Discovery represents and warrants that it has not used any broker, finder or
financial advisor in connection with the Merger but that it intends to retain
a financial advisor to render a fairness opinion in accordance with Section
7.16 of this Agreement.
 
                                     C-22

  11.3 Amendment. This Agreement shall not be amended except by a writing duly
executed by both parties.
 
  11.4 Governing Law. This Agreement shall be governed by and construed in
accordance with the laws of this State of Delaware as applied to agreements
entered into by Delaware residents and entirely to be performed within
Delaware.
 
  11.5 Headings. The headings contained in this Agreement are intended for
convenience and shall not be used to determine the rights of the parties.
 
  11.6 Mutual Contribution. The parties to this Agreement and their counsel
have mutually contributed to its drafting.
 
  11.7 Notices. All notices, requests, demands, and other communications made
in connection with this Agreement shall be in writing and shall be deemed to
have been duly given on the date of delivery if delivered by hand delivery or
by facsimile to the persons identified below or five days after mailing if
mailed by certified or registered mail postage prepaid return receipt
requested addressed as follows:

    If to Ansan:
 
      Ansan Pharmaceuticals, Inc.
      400 Oyster Point Blvd.
      South San Francisco, CA 94080
      Attention: Vaughan Shalson
      Facsimile: (415) 635-0211
      Confirmation Number: (415) 635-0200
 
    With a copy to:
 
      Heller, Ehrman, White & McAuliffe
      525 University Avenue
      Palo Alto, California 94301
      Attention: August J. Moretti
      Facsimile: (415) 324-0638
      Confirmation Number: (415) 324-7000
 
    If to Discovery:
 
      Discovery Laboratories, Inc.
      509 Madison Avenue
      New York, New York 10022
      Attention: President
      Facsimile: (212) 688-7978
      Confirmation Number: (212) 223-0960
 
    With a copy to:
 
      Roberts, Sheridan & Kotel, A Professional Corporation
      12 East 49th Street
      New York, New York 10017
      Attention: Kenneth Alberstadt
      Facsimile: (212) 299-8686
      Confirmation Number: (212) 299-8640
 
  Such addresses may be changed, from time to time by means of a notice given
in the matter provided in this section.
 
                                     C-23

  11.8 Severability. If any provision of this Agreement is held to be
unenforceable for any reason, it shall be adjusted rather than voided, if
possible, in order to achieve the intent of the parties to the extent
possible. In any event, all other provisions of this Agreement shall be deemed
valid and enforceable to the full extent.
 
  11.9 Termination of Representation and Warranties. All representations and
warranties contained in this Agreement, including the exhibits, schedules and
other documents delivered pursuant to this Agreement shall terminate at the
Effective Time.
 
  11.10 Waiver. Waiver of any term or condition of this Agreement by any party
shall not be construed as a waiver of a subsequent breach or failure of the
same term or condition, or a waiver of any other term or condition in this
Agreement.
 
  11.11 Assignment. Neither party may assign, by operation of law or
otherwise, all or any portion of its rights or duties under this Agreement
without the prior written consent of the other party, which consent may be
withheld in the absolute discretion of the party asked to give consent.
 
  11.12 Counterparts. This Agreement may be signed in counterparts with the
same effect as if the signatures to each party were upon a single instrument.
All counterparts shall be deemed an original of this Agreement.
 
  11.13 Voting Agreements of Certain Discovery Stockholders. Within 14 days of
the execution of this Agreement, each director of Discovery, as well as RAQ,
LLC, shall enter into a voting agreement and irrevocable proxy in the form
attached hereto as Exhibit 11.13, pursuant to which they shall agree to vote
all the shares of Discovery Stock held by them in favor of the Merger.
 
  11.14 Voting Agreements of Ansan Stockholder. Within 14 days of the
execution of this Agreement, Titan shall enter into a voting agreement and
irrevocable proxy in substantially the form attached hereto as Exhibit 11.14,
pursuant to which Titan shall agree to vote all the shares of Ansan Stock held
by it in favor of the Merger.
 
  11.15 Other Remedies. No remedies contained in this Agreement or in any of
the exhibits or schedules hereto shall be in lieu of, or constitute a waiver
of, any remedies at law or in equity (not based upon negligent
misrepresentation) that one party may otherwise have against the other party
hereto or against any present or former officer, director or controlling
stockholder of such party.
 
  11.16 No Solicitation of Employees. Until the Effective Date or six months
after termination of this Agreement, whichever is later, each of Ansan and
Discovery agrees that it will not solicit for hire any of the employees of the
other.
 
  11.17 Entire Agreement. This Agreement, including the exhibit, schedules,
and other documents delivered pursuant to this Agreement, contains all the
terms and conditions agreed upon by the parties relating to the subject matter
of this Agreement and supersedes all prior agreements, negotiations,
correspondence, undertakings, and communications of the parties, whether oral
or
 
  11.18 written, respecting that subject matter, except the nondisclosure
agreements between Discovery and Ansan and ATI and Ansan.
 
                                     C-24

  IN WITNESS WHEREOF, Ansan and Discovery have executed this Agreement as of
the date first above written.
 
                                          ANSAN PHARMACEUTICALS, INC.
 
                                          By: _________________________________
                                          Title: ______________________________
 
                                          DISCOVERY LABORATORIES, INC.
 
                                          By: _________________________________
                                          Title: ______________________________
 
                                      C-25

                                    ANNEX D
 
                                                                      EXHIBIT B
 
                             CERTIFICATE OF MERGER
                                    MERGING
                         DISCOVERY LABORATORIES, INC.
                                 WITH AND INTO
                          ANSAN PHARMACEUTICALS, INC.
 
           Pursuant to Section 251 of the General Corporation Law of
                             the State of Delaware
 
  Discovery Laboratories, Inc., a Delaware corporation ("Discovery") and Ansan
Pharmaceuticals, Inc., a Delaware corporation ("Ansan"), DO HEREBY CERTIFY AS
FOLLOWS:
 
  FIRST: That Discovery was incorporated on May 18, 1993, pursuant to the
Delaware General Corporation Law (the "Delaware Law"), and that Ansan was
incorporated on November 6, 1992, pursuant to the Delaware Law.
 
  SECOND: That an Agreement and Plan of Reorganization and Merger (the "Merger
Agreement"), dated as of July   , 1997, among Ansan and Discovery, setting
forth the terms and conditions of the merger of Discovery with and into Ansan
(the "Merger"), has been approved, adopted, certified, executed and
acknowledged by each of the constituent corporations in accordance with
Section 251 of the Delaware Law.
 
  THIRD: That the name of the surviving corporation (the "Surviving
Corporation") shall be "        "
 
  FOURTH: That pursuant to the Merger Agreement, the Certificate of
Incorporation of the Surviving Corporation is amended to read in its entirety
as set forth in Exhibit A hereto.
 
  FIFTH: That an executed copy of the Merger Agreement is on file at the
principal place of business of the Surviving Corporation at the following
address:
 
                              509 Madison Avenue
                           New York, New York 10022
 
  SIXTH: That a copy of the Merger Agreement will be furnished by the
Surviving Corporation, on request and without cost, to any stockholder of any
constituent corporation.
 
  SEVENTH: That the Merger shall become effective at       [am/pm] on the day
of filing of this Certificate of Merger with the Secretary of State of the
State of Delaware.
 
  IN WITNESS WHEREOF, each of Discovery and Ansan has caused this Certificate
of Merger to be executed in its corporate name this    day of        , 1997.
 
                                          DISCOVERY LABORATORIES, INC.

                                          _____________________________________
 
                                          By:
                                          Its:
 
                                          ANSAN PHARMACEUTICALS, INC.

                                          _____________________________________
                                          By:
                                          Its:
 
                                      D-1

                                    ANNEX E
 
                             262 APPRAISAL RIGHTS
 
  (a) Any stockholder of a corporation of this State who holds shares of stock
on the date of the making of a demand pursuant to subsection (d) of this
section with respect to such shares, who continuously holds such shares
through the effective date of the merger or consolidation, who has otherwise
complied with subsection (d) of this section and who has neither voted in
favor of the merger or consolidation nor consented thereto in writing pursuant
to (S) 228 of this title shall be entitled to an appraisal by the Court of
Chancery of the fair value of the stockholder's shares of stock under the
circumstances described in subsections (b) and (c) of this section. As used in
this section, the word "stockholder" means a holder of record of stock in a
stock corporation and also a member of record of a nonstock corporation; the
words "stock" and "share" mean and include what is ordinarily meant by those
words and also membership or membership interest of a member of a nonstock
corporation; and the words "depository receipt" mean a receipt or other
instrument issued by a depository representing an interest in one or more
shares, or fractions thereof, solely of stock of a corporation, which stock is
deposited with the depository.
 
  (b) Appraisal rights shall be available for the shares of any class or
series of stock of a constituent corporation in a merger or consolidation to
be effected pursuant to (S) 251 (other than a merger effected pursuant to (S)
251(g) of this title), (S) 252, (S) 254, (S) 257, (S) 258, (S) 263 or (S) 264
of this title:
 
    (1) Provided, however, that no appraisal rights under this section shall
  be available for the shares of any class or series of stock, which stock,
  or depository receipts in respect thereof, at the record date fixed to
  determine the stockholders entitled to receive notice of and to vote at the
  meeting of stockholders to act upon the agreement of merger or
  consolidation, were either (i) listed on a national securities exchange or
  designated as a national market system security on an interdealer quotation
  system by the National Association of Securities Dealers, Inc. or (ii) held
  of record by more than 2,000 holders; and further provided that no
  appraisal rights shall be available for any shares of stock of the
  constituent corporation surviving a merger if the merger did not require
  for its approval the vote of the stockholders of the surviving corporation
  as provided in subsection (f) of (S) 251 of this title.
 
    (2) Notwithstanding paragraph (1) of this subsection, appraisal rights
  under this section shall be available for the shares of any class or series
  of stock of a constituent corporation if the holders thereof are required
  by the terms of an agreement of merger or consolidation pursuant to (S)(S)
  251, 252, 254, 257, 258, 263 and 264 of this title to accept for such stock
  anything except:
 
      a. Shares of stock of the corporation surviving or resulting from
    such merger or consolidation, or depository receipts in respect
    thereof;
 
      b. Shares of stock of any other corporation, or depository receipts
    in respect thereof, which shares of stock or depository receipts at the
    effective date of the merger or consolidation will be either listed on
    a national securities exchange or designated as a national market
    system security on an interdealer quotation system by the National
    Association of Securities Dealers, Inc. or held of record by more than
    2,000 holders;
 
      c. Cash in lieu of fractional shares or fractional depository
    receipts described in the foregoing subparagraphs a. and b. of this
    paragraph; or
 
      d. Any combination of the shares of stock, depository receipts and
    cash in lieu of fractional shares or fractional depository receipts
    described in the foregoing subparagraphs a. b. and c. of this
    paragraph.
 
    (3) In the event all of the stock of a subsidiary Delaware corporation
  party to a merger effected under (S) 253 of this title is not owned by the
  parent corporation immediately prior to the merger, appraisal rights shall
  be available for the shares of the subsidiary Delaware corporation.
 
                                      E-1

  (c) Any corporation may provide in its certificate of incorporation that
appraisal rights under this section shall be available for the shares of any
class or series of its stock as a result of an amendment to its certificate of
incorporation, any merger or consolidation in which the corporation is a
constituent corporation or the sale of all or substantially all of the assets
of the corporation. If the certificate of incorporation contains such a
provision, the procedures of this section, including those set forth in
subsections (d) and (e) of this section, shall apply as nearly as is
practicable.
 
  (d) Appraisal rights shall be perfected as follows:
 
    (1) If a proposed merger or consolidation for which appraisal rights are
  provided under this section is to be submitted for approval at a meeting of
  stockholders, the corporation, not less than 20 days prior to the meeting,
  shall notify each of its stockholders who was such on the record date for
  such meeting with respect to shares for which appraisal rights are
  available pursuant to subsections (b) or (c) hereof that appraisal rights
  are available for any or all of the shares of the constituent corporations,
  and shall include in such notice a copy of this section. Each stockholder
  electing to demand the appraisal of his shares shall deliver to the
  corporation, before the taking of the vote on the merger or consolidation,
  a written demand for appraisal of his shares. Such demand will be
  sufficient if it reasonably informs the corporation of the identity of the
  stockholder and that the stockholder intends thereby to demand the
  appraisal of his shares. A proxy or vote against the merger or
  consolidation shall not constitute such a demand. A stockholder electing to
  take such action must do so by a separate written demand as herein
  provided. Within 10 days after the effective date of such merger or
  consolidation, the surviving or resulting corporation shall notify each
  stockholder of each constituent corporation who has complied with this
  subsection and has not voted in favor of or consented to the merger or
  consolidation of the date that the merger or consolidation has become
  effective; or
 
    (2) If the merger or consolidation was approved pursuant to (S) 228 or
  (S) 253 of this title, each constituent corporation, either before the
  effective date of the merger or consolidation or within ten days
  thereafter, shall notify each of the holders of any class or series of
  stock of such constituent corporation who are entitled to appraisal rights
  of the approval of the merger or consolidation and that appraisal rights
  are available for any or all shares of such class or series of stock of
  such constituent corporation, and shall include in such notice a copy of
  this section; provided that, if the notice is given on or after the
  effective date of the merger or consolidation, such notice shall be given
  by the surviving or resulting corporation to all such holders of any class
  or series of stock of a constituent corporation that are entitled to
  appraisal rights. Such notice may, and, if given on or after the effective
  date of the merger or consolidation, shall, also notify such stockholders
  of the effective date of the merger or consolidation. Any stockholder
  entitled to appraisal rights may, within 20 days after the date of mailing
  of such notice, demand in writing from the surviving or resulting
  corporation the appraisal of such holder's shares. Such demand will be
  sufficient if it reasonably informs the corporation of the identity of the
  stockholder and that the stockholder intends thereby to demand the
  appraisal of such holder's shares. If such notice did not notify
  stockholders of the effective date of the merger or consolidation, either
  (i) each such constituent corporation shall send a second notice before the
  effective date of the merger or consolidation notifying each of the holders
  of any class or series of stock of such constituent corporation that are
  entitled to appraisal rights of the effective date of the merger or
  consolidation or (ii) the surviving or resulting corporation shall send
  such a second notice to all such holders on or within 10 days after such
  effective date; provided, however, that if such second notice is sent more
  than 20 days following the sending of the first notice, such second notice
  need only be sent to each stockholder who is entitled to appraisal rights
  and who has demanded appraisal of such holder's shares in accordance with
  this subsection. An affidavit of the secretary or assistant secretary or of
  the transfer agent of the corporation that is required to give either
  notice that such notice has been given shall, in the absence of fraud, be
  prima facie evidence of the facts stated therein. For purposes of
  determining the stockholders entitled to receive either notice, each
  constituent corporation may fix, in advance, a record date that shall be
  not more than 10 days prior to the date the notice is given, provided, that
  if the notice is given on or after the effective date of the merger or
  consolidation, the record date shall be such effective date. If no record
  date is fixed and the notice is given prior to the effective date, the
  record date shall be the close of business on the day next preceding the
  day on which the notice is given.
 
                                      E-2

  (e) Within 120 days after the effective date of the merger or consolidation,
the surviving or resulting corporation or any stockholder who has complied
with subsections (a) and (d) hereof and who is otherwise entitled to appraisal
rights, may file a petition in the Court of Chancery demanding a determination
of the value of the stock of all such stockholders. Notwithstanding the
foregoing, at any time within 60 days after the effective date of the merger
or consolidation, any stockholder shall have the right to withdraw his demand
for appraisal and to accept the terms offered upon the merger or
consolidation. Within 120 days after the effective date of the merger or
consolidation, any stockholder who has complied with the requirements of
subsections (a) and (d) hereof, upon written request, shall be entitled to
receive from the corporation surviving the merger or resulting from the
consolidation a statement setting forth the aggregate number of shares not
voted in favor of the merger or consolidation and with respect to which
demands for appraisal have been received and the aggregate number of holders
of such shares. Such written statement shall be mailed to the stockholder
within 10 days after his written request for such a statement is received by
the surviving or resulting corporation or within 10 days after expiration of
the period for delivery of demands for appraisal under subsection (d) hereof,
whichever is later.
 
  (f) Upon the filing of any such petition by a stockholder, service of a copy
thereof shall be made upon the surviving or resulting corporation, which shall
within 120 days after such service file in the office of the Register in
Chancery in which the petition was filed a duly verified list containing the
names and addresses of all stockholders who have demanded payment for their
shares and with whom agreements as to the value of their shares have not been
reached by the surviving or resulting corporation. If the petition shall be
filed by the surviving or resulting corporation, the petition shall be
accompanied by such a duly verified list. The Register in Chancery, if so
ordered by the Court, shall give notice of the time and place fixed for the
hearing of such petition by registered or certified mail to the surviving or
resulting corporation and to the stockholders shown on the list at the
addresses therein stated. Such notice shall also be given by 1 or more
publications at least 1 week before the day of the hearing, in a newspaper of
general circulation published in the City of Wilmington, Delaware or such
publication as the Court deems advisable. The forms of the notices by mail and
by publication shall be approved by the Court, and the costs thereof shall be
borne by the surviving or resulting corporation.
 
  (g) At the hearing on such petition, the Court shall determine the
stockholders who have complied with this section and who have become entitled
to appraisal rights. The Court may require the stockholders who have demanded
an appraisal for their shares and who hold stock represented by certificates
to submit their certificates of stock to the Register in Chancery for notation
thereon of the pendency of the appraisal proceedings; and if any stockholder
fails to comply with such direction, the Court may dismiss the proceedings as
to such stockholder.
 
  (h) After determining the stockholders entitled to an appraisal, the Court
shall appraise the shares, determining their fair value exclusive of any
element of value arising from the accomplishment or expectation of the merger
or consolidation, together with a fair rate of interest, if any, to be paid
upon the amount determined to be the fair value. In determining such fair
value, the Court shall take into account all relevant factors. In determining
the fair rate of interest, the Court may consider all relevant factors,
including the rate of interest which the surviving or resulting corporation
would have had to pay to borrow money during the pendency of the proceeding.
Upon application by the surviving or resulting corporation or by any
stockholder entitled to participate in the appraisal proceeding, the Court
may, in its discretion, permit discovery or other pretrial proceedings and may
proceed to trial upon the appraisal prior to the final determination of the
stockholder entitled to an appraisal. Any stockholder whose name appears on
the list filed by the surviving or resulting corporation pursuant to
subsection (f) of this section and who has submitted his certificates of stock
to the Register in Chancery, if such is required, may participate fully in all
proceedings until it is finally determined that he is not entitled to
appraisal rights under this section.
 
  (i) The Court shall direct the payment of the fair value of the shares,
together with interest, if any, by the surviving or resulting corporation to
the stockholders entitled thereto. Interest may be simple or compound, as the
Court may direct. Payment shall be so made to each such stockholder, in the
case of holders of uncertificated stock forthwith, and the case of holders of
shares represented by certificates upon the surrender to the corporation
 
                                      E-3

of the certificates representing such stock. The Court's decree may be
enforced as other decrees in the Court of Chancery may be enforced, whether
such surviving or resulting corporation be a corporation of this State or of
any state.
 
  (j) The costs of the proceeding may be determined by the Court and taxed
upon the parties as the Court deems equitable in the circumstances. Upon
application of a stockholder, the Court may order all or a portion of the
expenses incurred by any stockholder in connection with the appraisal
proceeding, including, without limitation, reasonable attorney's fees and the
fees and expenses of experts, to be charged pro rata against the value of all
the shares entitled to an appraisal.
 
  (k) From and after the effective date of the merger or consolidation, no
stockholder who has demanded his appraisal rights as provided in subsection
(d) of this section shall be entitled to vote such stock for any purpose or to
receive payment of dividends or other distributions on the stock (except
dividends or other distributions payable to stockholders of record at a date
which is prior to the effective date of the merger or consolidation);
provided, however, that if no petition for an appraisal shall be filed within
the time provided in subsection (e) of this section, or if such stockholder
shall deliver to the surviving or resulting corporation a written withdrawal
of his demand for an appraisal and an acceptance of the merger or
consolidation, either within 60 days after the effective date of the merger or
consolidation as provided in subsection (e) of this section or thereafter with
the written approval of the corporation, then the right of such stockholder to
an appraisal shall cease. Notwithstanding the foregoing, no appraisal
proceeding in the Court of Chancery shall be dismissed as to any stockholder
without the approval of the Court, and such approval may be conditioned upon
such terms as the Court deems just.
 
  (l) The shares of the surviving or resulting corporation to which the shares
of such objecting stockholders would have been converted had they assented to
the merger or consolidation shall have the status of authorized and unissued
shares of the surviving or resulting corporation.
 
                                      E-4

                                    PART II
 
                    INFORMATION NOT REQUIRED IN PROSPECTUS
 
ITEM 20. INDEMNIFICATION OF DIRECTORS AND OFFICERS
 
  Section 145 of the Delaware General Corporation Law (the "DGCL") permits a
Delaware corporation to indemnify officers, directors, employees and agents
for actions taken in good faith and in a manner they reasonably believed to be
in, or not opposed to, the best interests of the corporation, and with respect
to any criminal action, which they had no reasonable cause to believe was
unlawful. The DGCL provides that a corporation may pay expense (including
attorneys' fees) incurred by an officer or Director in defending any civil,
criminal, administrative or investigative action (upon receipt of a written
undertaking to reimburse the corporation if indemnification is not
appropriate), and must reimburse a successful defendant for expenses,
including attorney's fees, actually and reasonably incurred, and permits a
corporation to purchase and maintain liability insurance for its directors and
officers. The DGCL provides that indemnification may be made for any claim,
issue or matter as to which a person has been adjudged by a court of competent
jurisdiction, after exhaustion of all appeals therefrom, to be liable to the
corporation, unless and only to the extent a court determines that the person
is entitled to indemnity for such expenses as the court deems proper.
 
  The Amended and Restated Certificate of Incorporation of Ansan (the "Ansan
Certificate") and the Bylaws of Ansan (the "Ansan Bylaws") provide, among
other things, that, to the fullest extent authorized by the DGCL, Ansan
indemnify each person who is or has served as a director or officer of Ansan
or any predecessor of Ansan, or any other enterprise at the request of Ansan
or of any predecessor of Ansan, against expenses (including attorneys' fees),
judgments, fines, settlements, and other amounts actually and reasonably
incurred in connection with any proceeding, arising by reason of the fact that
such person is or was an agent of Ansan. Ansan may also indemnify each of its
employees and agents against expenses (including attorneys' fees), judgments,
fines, settlements, and other amounts actually and reasonably incurred in
connection with any proceeding arising by reason of the fact that such person
is or was an agent of Ansan.
 
  The DGCL permits a Delaware corporation to include a provision in its
certificate of incorporation eliminating or limiting the personal liability of
any director to the corporation or its stockholders for monetary damages for a
breach of the director's fiduciary duty as a director, except for liability
(i) for any breach of the director's duty of loyalty to the corporation or its
stockholders, (ii) for acts or omissions not in good faith or which involve
intentional misconduct or a knowing violation of law, (iii) under Section 174
of the DGCL, which concerns unlawful payments of dividends, stock purchases or
redemptions or (iv) for any transaction from which the director derived an
improper personal benefit. The Ansan Certificate contains provisions limiting
the liability of its directors, to the fullest extent currently permitted by
the DGCL for monetary damages for breach of their fiduciary duty as directors.
 
  While these provisions provide directors with protection from awards for
monetary damages for breaches of their duty of care, they do not eliminate
such duty. Accordingly, these provisions will have no effect on the
availability of equitable remedies such as an injunction or rescission based
on a director's breach of his or her duty of care.
 
  Ansan has purchased insurance which purports to insure Ansan against certain
costs of indemnification which may be incurred by it pursuant to the Ansan
Certificate and the Ansan Bylaws and to insure the officers and directors of
Ansan against certain liabilities incurred by them in the discharge of their
functions as such officers and directors except for liabilities resulting from
their own malfeasance.
 
                                     II-1

ITEM 21. EXHIBITS AND FINANCIAL STATEMENT SCHEDULES
 
  (a) The following is a list of Exhibits included as part of this
Registration Statement. Ansan agrees to furnish supplementally a copy of any
omitted schedule to the Commission upon request. Items marked with an asterisk
are filed herewith.

 
           
     2.1**     Agreement and Plan of Reorganization and Merger, dated as of
               July 16, 1997, by and between Ansan Pharmaceuticals, Inc. and
               Discovery Laboratories, Inc. (included as Annex C to the
               Prospectus/Proxy Statement). 
     2.2**     Form of Affiliate's Agreement, undated. 
     2.3**     Form of Lock-Up Agreement, undated, for Discovery stockholders
               that were not participants in the Unit Offering. 
     2.4**     Form of Lock-Up Agreement, undated, for Discovery stockholders
               that were participants in the Unit Offering. 
     2.5**     Voting Agreement, dated as of August 4, 1997, by and between
               Discovery and Titan. 
     2.6**     Form of Voting Agreement, undated, by and between Ansan and
               certain stockholders of Discovery. 
     3.1***    Amended and Restated Certificate of Incorporation of Ansan.
     3.2***    By-laws of Ansan. 
     4.1***    Form of Specimen Stock Certificate of Ansan. 
     4.2***    Form of Bridge Note. 
     4.3***    Bridge of Warrant Agreement. 
     4.4***    Form of Warrant Agreement. 
     4.5***    Form of Underwriter's Unit Purchase Option. 
     4.6***    Investor Rights Agreement, dated May 31, 1994, between Ansan
               and Titan. 
     4.7***    Form of Option Agreement between Ansan and Titan.
     5.1**     Opinion of Heller Ehrman White & McAuliffe to Discovery as to
               certain general corporate matters and as to the legality of the
               securities being issued.
     5.2       Deleted.                                                      
     8.1*      Opinion of Heller Ehrman White & McAuliffe as to certain
               United States federal income tax consequences of the Merger.
     8.2*      Opinion of Roberts, Sheridan & Kotel as to certain United
               States federal income tax consequences of the Merger. 
    10.1***    License Agreement between Ansan and Bar-Ilan dated October 31,
               1992. 
    10.2***    Restated 1993 Stock Option Plan of Ansan.
    10.3***    1995 Stock Option Plan of Ansan. 
    10.4***    Form of Escrow Agreement by and between Ansan, Continental
               Stock Transfer & Trust Company and certain securityholders of
               Ansan. 
    10.5***    Form of Indemnification Agreement. 
    10.6***    Conversion Agreement, dated May 23, 1995, between Ansan and
               Titan. 

 
                                     II-2

    10.7****  Lease for Registrant's facility.
 
   (1)10.8****License Agreement dated May 31, 1996, between Boehringer
              Ingelheim and Ansan.
 
    11.1***** Statement of Computation of Net Loss Per Share.
       
    23.1**    Consent of Heller Ehrman White & McAuliffe (included in its
              opinion filed as Exhibit 5.1).     
       
    23.2*     Consent of Roberts, Sheridan & Kotel (included in its opinion
              filed as Exhibit 8.2).     
 
    23.3*     Consent of Ernst & Young LLP.
 
    23.4*     Consent of Richard A. Eisner & Company, LLP.
 
    24.1**    Power of Attorney (see Page II-5).
 
    99.1**    Form of Proxy Card to be mailed to holders of Ansan.
 
    99.2**    Form of Written Consent to be mailed to holders of Discovery.
       
    99.3*     Consent of Persons About to Become Directors.     
       
    99.4**    Consent of Dakin Securities Corporation.     
       
    99.5**    Consent of Sands Brothers & Co., Ltd.     
- --------
    * Filed herewith.
   
   ** Previously filed.     
 
  *** Incorporated by reference to Ansan's Registration Statement on Form SB-2
         (File No. 33-92886).
 
 **** Incorporated by reference to Ansan's Annual Report on Form 10-K-SB for
      year ended December 31, 1995.
 
***** Incorporated by reference from the Exhibits to Ansan's Quarterly Report
      on Form 10-QSB for the period ended June 30, 1996.
 
  (1) Confidential treatment has been granted with respect to portions of this
exhibit.
 
  (b) Financial Data Schedules. Not applicable.
 
ITEM 22. UNDERTAKINGS

  (1) The undersigned Registrant hereby undertakes that it will:
 
    (a) File, during any period in which offers or sales are being made, a
  post-effective amendment to this registration statement to:
 
      (i) Include any prospectus required by Section 10(a)(3) of the
    Securities Act,
 
      (ii) Reflect in the prospectus any facts or events which,
    individually or together, represent a fundamental change in the
    information in the registration statement, and
 
      (iii) Include any additional or changed material information on the
    plan of distribution.
 
    (b) For determining liability under the Securities Act, treat each post-
  effective amendment as a new registration statement of the securities
  offered, and the offering of the securities at that time to be the initial
  bona fide offering.
 
    (c) File a post-effective amendment to remove from registration any of
  the securities that remain unsold at the end of this offering.

                                     II-3

  (2) Insofar as indemnification for liabilities arising under the Securities
Act may be permitted to directors, officers and controlling persons of the
Registrant pursuant to the foregoing provisions, or otherwise, the Registrant
has been advised that in the opinion of the Commission such indemnification is
against public policy as expressed in the Securities Act and is, therefore,
unenforceable. In the event that a claim for indemnification against such
liabilities (other than the payment by the Registrant of expenses incurred or
paid by a director, officer or controlling person of the Registrant in the
successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities
being registered, the Registrant will, unless in the opinion of its counsel
the matter has been settled by controlling precedent, submit to a court of
appropriate jurisdiction the question whether such indemnification by it is
against public policy as expressed in the Securities Act and will be governed
by the final adjudication of each issue.

                                     II-4

                                  SIGNATURES
   
  Pursuant to the requirements of the Securities Act of 1933, ANSAN
PHARMACEUTICALS, INC. has duly caused this Amendment No. 2 to the Registration
Statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of South San Francisco, State of California, on
October 23, 1997.     
 
                                          ANSAN PHARMACEUTICALS, INC.
 
                                                 /s/ Vaughan H. J. Shalson
                                          By: _________________________________
                                                   Vaughan H. J. Shalson
                                               President and Chief Executive
                                                          Officer
 
                               POWER OF ATTORNEY
 
  KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears
below constitutes and appoints Vaughan H. J. Shalson and James M. Ahlers, or
either of them, with the power of substitution, his attorney in fact, to sign
any amendments to this Registration Statement (including post-effective
amendments), and to file the same, with exhibits thereto and other documents
in connection therewith, with the Securities and Exchange Commission, hereby
ratifying and confirming all that each of said attorney-in-fact, or his
substitute or substitutes, may do or case to be done by virtue hereof.
 
  Pursuant to the requirements of the Securities Act of 1933, this Amendment
No. 1 to the Registration Statement has been signed by the following persons
in the capacities and on the dates indicated.

             SIGNATURE                         CAPACITY                   DATE
             ---------                         --------                   ----

          Louis R. Bucalo*           Chairman of the Board of       October 23, 1997
____________________________________ Directors
       Louis R. Bucalo, M.D.
 
    /s/ Vaughan H. J. Shalson        President and Chief            October 23, 1997
____________________________________ Executive Officer (Principal
       Vaughan H. J. Shalson         Executive Officer)
        (* attorney in fact)

       /s/ James M. Ahlers           Director of Finance and        October 23, 1997
____________________________________ Operations (Principal
          James M. Ahlers            Financial and Accounting
                                     Officer)

                                     Director
____________________________________ 
     Lindsay A. Rosenwald, M.D.
 
          Richard Sperber*           Director                       October 23, 1997
____________________________________
          Richard Sperber

         Ilan Cohn, Ph.D.*           Director                       October 23, 1997
____________________________________
          Ilan Cohn, Ph.D.
 
        David Naveh, Ph.D.*          Director                       October 23, 1997
____________________________________
         David Naveh, Ph.D.

                                     II-5

                                 EXHIBIT INDEX

 
 EXHIBIT                               DESCRIPTION                              SEQUENTIALLY
   NO.                                 -----------                             NUMBERED PAGE
 -------                                                                       -------------
                                                                        
   2.1**   Agreement and Plan of Reorganization and Merger,
           dated as of July 16, 1997, by and between Ansan
           Pharmaceuticals, Inc. and Discovery Laboratories,
           Inc. (included as Annex C to the Prospectus/Proxy
           Statement).
 
   2.2**   Form of Affiliate's Agreement, undated.
 
   2.3**   Form of Lock-Up Agreement, undated, for Discovery
           stockholders that were not participants in the Unit
           Offering.
 
   2.4**   Form of Lock-Up Agreement, undated, for Discovery
           stockholders that were participants in the Unit
           Offering.
 
   2.5**   Voting Agreement, dated as of August 4, 1997, by and
           between Discovery and Titan.
     
   2.6**   Form of Voting Agreement, undated, by and between
           Ansan and certain stockholders of Discovery.     
 
   3.1***  Amended and Restated Certificate of Incorporation of
           Ansan.
 
   3.2***  By-laws of Ansan.
 
   4.1***  Form of Specimen Stock Certificate of Ansan.
 
   4.2***  Form of Bridge Note.
 
   4.3***  Bridge of Warrant Agreement.
 
   4.4***  Form of Warrant Agreement.
 
   4.5***  Form of Underwriter's Unit Purchase Option.
 
   4.6***  Investor Rights Agreement, dated May 31, 1994,
           between Ansan and Titan.
 
   4.7***  Form of Option Agreement between Ansan and Titan.
     
   5.1**   Opinion of Heller Ehrman White & McAuliffe to
           Discovery as to certain general corporate matters and
           as to the legality of the securities being issued.

   
   8.1*    Opinion of Heller Ehrman White & McAuliffe as to
           certain United States federal income tax consequences
           of the Merger.     
     
   8.2*    Opinion of Roberts, Sheridan & Kotel as to certain
           United States federal income tax consequences of the
           Merger.     
 
  10.1***  License Agreement between Ansan and Bar-Ilan dated
           October 31, 1992.
 
  10.2***  Restated 1993 Stock Option Plan of Ansan.
 
  10.3***  1995 Stock Option Plan of Ansan.
 
  10.4***  Form of Escrow Agreement by and between Ansan,
           Continental Stock Transfer & Trust Company and
           certain securityholders of Ansan.
 
  10.5***  Form of Indemnification Agreement.
 
  10.6***  Conversion Agreement, dated May 23, 1995, between
           Ansan and Titan.

 
                          EXHIBIT INDEX--(CONTINUED)

 
 EXHIBIT                               DESCRIPTION                              SEQUENTIALLY
   NO.                                 -----------                             NUMBERED PAGE
 -------                                                                       -------------

  10.7****   Lease for Registrant's facility.
 
 (1)10.8**** License Agreement dated May 31, 1996, between
             Boehringer Ingelheim and Ansan.
 
  11.1*****  Statement of Computation of Net Loss Per Share.
     
  23.1**     Consent of Heller Ehrman White & McAuliffe (included
             in its opinion filed as Exhibit 5.1).     
     
  23.2*      Consent of Roberts, Sheridan & Kotel (included in its
             opinion filed as Exhibit 8.2).     
 
  23.3*      Consent of Ernst & Young LLP.
 
  23.4*      Consent of Richard A. Eisner & Company, LLP.
 
  24.1**     Power of Attorney (see Page II-5).
 
  99.1**     Form of Proxy Card to be mailed to holders of Ansan.
 
  99.2**     Form of Written Consent to be mailed to holders of
             Discovery.
     
  99.3*      Consent of Persons About to Become Directors.     
     
  99.4**     Consent of Dakin Securities Corporation.     
     
  99.5**     Consent of Sands Brothers & Co., Ltd.     
 
- --------
     * Filed herewith.
   
    ** Previously filed.     
 
   *** Incorporated by reference to Ansan's Registration Statement on Form SB-2
       (File No. 33-92886).
 
  **** Incorporated by reference to Ansan's Annual Report on Form 10-K-SB for
       year ended December 31, 1995.
 
 ***** Incorporated by reference from the Exhibits to Ansan's Quarterly Report
       on Form 10-QSB for the period ended June 30, 1996.
       
   (1) Confidential treatment has been granted with respect to portions of this
exhibit.

 
                                                                     EXHIBIT 8.1

                [Letterhead of Heller Ehrman White & McAuliffe]
                                  
                              October 23, 1997      

Ansan Pharmaceuticals, Inc.
400 Oyster Point Boulevard
South San Francisco, California 94080

Ladies and Gentlemen:

        You have requested our opinion regarding certain federal income tax 
consequences of the proposed merger (the "Merger") of Discovery Laboratories, 
Inc. ("Discovery"), with and into Ansan Pharmaceuticals, Inc. ("Ansan"). We 
have acted as counsel to Ansan in connection with the Merger, and have 
examined the Agreement and Plan of Reorganization and Merger dated July 16, 
1997, between Ansan, and Discovery (the "Agreement") and the exhibits and 
attachments thereto. In addition, we have received written representations 
pertaining to the Merger from Ansan, Discovery and certain shareholders of 
Discovery. Our opinions are based upon the understanding that the material 
facts are as described in the Agreement and appurtenant documents and that the
Merger will be effected in accordance with the terms set forth in the 
Agreement, and in rendering our opinions we have relied upon such documents 
and the foregoing representations without undertaking independently to verify 
the accuracy and completeness of the matters covered thereby. Except as 
otherwise noted, capitalized terms used herein have the same meaning given to 
such terms in the Agreement.

        Based upon the foregoing, it is our opinion that:

1.  The Merger will constitute a "reorganization" within the meaning of
    Section 368(a) of the Internal Revenue Code of 1986, as amended (the
    "Code").

2.  By virtue of 1., above, for federal income tax purposes:

    a.  A Discovery shareholder receiving only Ansan stock in the Merger will 
        not recognize gain or loss in the Merger.

 
                                                                          Page 2
    
Ansan Pharmaceuticals Inc.
October 23, 1997      

    b.  Cash paid to a Discovery shareholder in lieu of a fractional share of
        Ansan common stock will be treated as having been received in payment in
        exchange for the Ansan common stock that otherwise would have been
        received in the Merger, and the Discovery shareholder will recognize
        gain or loss equal to the difference between the cash received in lieu
        of such fractional share and the Discovery shareholder's basis in the
        Discovery common stock surrendered therefor.

    c.  An exchanging Discovery shareholder will have the same aggregate tax
        basis in the Ansan stock received as he or she had in the Discovery
        stock surrendered in exchange therefor, reduced by any basis allocable
        to a fractional share of Ansan common stock for which cash was received.

    d.  The periods for which a Discovery shareholder has held his or her
        Discovery stock will be included in computing his or her holding periods
        for the Ansan stock received in the Merger, assuming the Discovery stock
        is held by the Discovery shareholder as a capital asset at the Effective
        Time.

    e.  Neither Discovery nor Ansan will recognize gain or loss solely as a 
        result of the Merger.

        Our opinion is subject to certain assumptions and qualifications, and is
based on the truth and accuracy of the representations of the parties in the 
Agreement and the Affiliates Agreements, and in representation letters to be 
delivered by Discovery and by you. Of particular importance is the assumption 
that the Merger will satisfy the "continuity of interest" and "continuity of 
business enterprise" requirements for reorganization treatment under Section 
368(a) of the Internal Revenue Code of 1986, as amended. If either of these 
requirements is not met, then the Merger cannot be a tax-free reorganization, 
and each Discovery shareholder would recognize gain or loss on the exchange of 
Discovery stock for Ansan stock.

        In order for the continuity of interest requirement to be met under 
existing law, Discovery shareholders must not, pursuant to a plan or intent 
existing at or before the Effective Time, dispose of an amount of Ansan stock to
be received in the Merger (including pre-Merger dispositions of Discovery stock 
in contemplation of the Merger)

                                                                          Page 3
    
Ansan Pharmaceuticals Inc.
October 23, 1997      
    
such that they do not retain a meaningful continuing equity ownership in Ansan.
Generally, so long as Discovery shareholders do not plan to dispose of a number
of shares of Ansan stock that would reduce their ownership of Ansan stock to a
number of shares having a value, as of the Effective Time, of less than 50
percent of the value of all of the formerly outstanding stock of Discovery as of
the same date, the continuity of interest requirement will be satisfied.
Management of Discovery and of Ansan have represented to us that they know of no
such plan or intention that would result in the continuity of interest
requirement not being satisfied. In order for the continuity of business
enterprise requirement to be met, Ansan must, after the Merger, either continue
Discovery's historic business or use a significant portion of Discovery's
historic business assets in a business. Management of Ansan has represented to
us that following the Merger Ansan will continue Discovery's historic business
or use a significant portion of Discovery's historic business assets in a
business.     

         *              *              *              *              *

                                                                          Page 3
    
Ansan Pharmaceuticals Inc.
October 23, 1997      

        Our opinions are limited to the federal income tax consequences of the 
Merger and do not address the tax consequences of transactions effected prior to
or after the Merger (whether or not in connection with the Merger), nor the 
effect of the Merger under the laws of the various state and local governments 
or under the laws of any other jurisdiction. Moreover, they do not address 
special rules which may be applicable to particular shareholders of Discovery, 
such as shareholders who acquired their shares pursuant to the exercise of 
statutory stock options, shareholders which are dealers or foreign persons, or 
shareholders who exercise dissenter's rights. We express no opinion regarding 
any tax aspect or ramification of the Merger apart from the opinions 
specifically set forth above.

        An opinion of counsel does not bind the Internal Revenue Service or 
preclude it or a court from taking a position contrary to the opinion. This 
opinion is rendered in connection with the Agreement. This opinion may not be 
relied upon for any other purpose without our written consent. This opinion is 
based upon the Code, the Treasury Regulations issued thereunder, and judicial 
and administrative interpretations thereof, all as in effect on the date of this
opinion. All of such authority is subject to change, including retroactive 
change. We disclaim any obligation to advise of any developments in areas 
covered by this opinion that occur after the date of this opinion.

        This opinion has been delivered to you for the purposes of satisfying 
the requirements of Section 6.7 of the Agreement. We hereby consent to the 
filing of this opinion as an exhibit to the Registration Statement. In giving 
this consent, however, we do not admit that we are in the category of persons 
whose consent is required under Section 7 of the Securities Act of 1933, as 
amended.

                               Very truly yours,

                        Heller Ehrman White & McAuliffe

                                                                     EXHIBIT 8.2

     [LETTERHEAD OF ROBERTS, SHERIDAN & KOTEL A PROFESSIONAL CORPORATION]

                                                                     
                                                         October 23, 1997

Discovery Laboratories, Inc.

Ladies and Gentlemen:

          We have acted as counsel to Discovery Laboratories, Inc., a Delaware
corporation ("Discovery"), in connection with the planned merger (the "Merger")
of Discovery with and into Ansan Pharmaceuticals, Inc. ("Ansan"), a Delaware
corporation, pursuant to the Agreement and Plan of Reorganization and Merger
dated July 16, 1997 (the "Transaction Agreement") between Discovery and Ansan
and as described in the Proxy Statement/Prospectus (the "Proxy Statement")
that is included in the Registration Statement on Form S-4 (the "Registration
Statement"), Registration No. 333-34337, covering the registration of Ansan
common shares ("Ansan Shares"), under the Securities Act of 1933, as amended
(the "Act"), as filed by Ansan with the Securities and Exchange Commission (the
"SEC") on August 23, 1997. Any capitalized terms not otherwise defined herein
shall have the meanings ascribed to them in the Transaction Agreement or, if not
defined therein, in the Proxy Statement.

          For purposes of this opinion we have assumed, with your consent, upon
the accuracy and completeness of the statements and representations contained in
(i) the Officer's Certificate of each of Ansan and Discovery, (attached hereto
as appendices 1 and 2), (ii) the Transaction Agreement, (iii) the Registration
Statement and (iv) the Proxy Statement, which statements and representations we
have not verified. We have also assumed that the Merger will be consummated in
accordance with the Transaction Agreement and as described in the Proxy
Statement.

          Based upon, and subject to the foregoing, we are of the opinion that, 
for United States federal income tax purposes:

          1.  The Merger will be treated as a reorganization within the meaning 
of Section 368(a) of the Internal Revenue Code of 1986, as amended (the "Code").

          2.  Each of Ansan and Discovery will be a party to such reorganization
within the meaning of Section 368(b) of the Code.

 
     3.    Except for cash received in lieu of fractional Ansan Shares, no gain 
or loss will be recognized by a stockholder of Discovery as a result of the 
Merger with respect to the shares of Discovery Stock converted into Ansan 
Shares.

     4.    An exchanging Discovery Shareholder will have the same aggregate tax 
basis in the Ansan Shares received as he or she had in the Discovery Shares 
surrendered in exchange therefor, reduced by any basis allocable to a fractional
share of Ansan Shares for which cash was received.

     5.    The holding period of Ansan Shares received by a Discovery 
Shareholder in the Merger will include the shareholder's holding period in the 
Discovery Shares exchanged therefor, provided such Discovery Shares constituted
a capital asset in the hands of the exchanging shareholder.

     6.    Neither Ansan nor Discovery will recognize gain or loss solely as a 
result of the Merger.

     Our opinion is based upon existing statutory, regulatory and judicial
authority as of the date hereof, any of which may be changed at any time,
possibly with retroactive effect, and is limited to the United States federal
income tax matters specifically addressed herein. In addition, this opinion 
(i) is based solely on the documents that we have examined, additional
information provided to us and the assumptions identified herein, and (ii) may
not be relied upon if any of the facts contained in those documents or if such
additional information, or such assumptions, are, or later become, inaccurate.
This opinion is rendered solely for your benefit in connection with transactions
contemplated in the Transaction Agreement and is not to be relied upon by you
for any other purpose or by any other person or firm for any purposes, in each
case without our express written consent.

     We hereby consent to the inclusion of our opinion as an exhibit to the 
Registration Statement and to the reference to our opinion under the caption 
"Legal Matters" in the Registration Statement.  We do not thereby admit that we 
are within the category of persons whose consent is required pursuant to Section
7 of the Securities Act of 1933, as amended.

                               Very truly yours,

           /s/ ROBERTS, SHERIDAN & KOTEL, A Professional Corporation

                                                                      Appendix 1
                                                                      ----------

                                   DISCOVERY
                             OFFICER'S CERTIFICATE

          In connection with the merger (the "Merger") of Discovery
Laboratories, Inc., a Delaware corporation ("Discovery") with and into Ansan
Pharmaceuticals, Inc., a Delaware corporation) ("Ansan") pursuant to the
Agreement and Plan of Reorganization and Merger by and between Ansan and
Discovery dated as of July 16, 1997, (the "Transaction Agreement"; capitalized
terms, unless otherwise defined herein, have the meanings ascribed to them in
the Transaction Agreement), and for purposes of the tax opinion to be rendered
by Heller Ehrman White & McAuliffe and Roberts, Sheridan & Kotel, the
undersigned officer of Discovery hereby represents on behalf of Discovery that,
to the best knowledge and belief of such officer, after due inquiry and
investigation, the facts relating to the Merger, as such facts are set forth in
the Transaction Agreement and insofar as such facts pertain to Discovery, are
true, correct, and complete in all material aspects.

          The undersigned further represents on behalf of Discovery that to the
best knowledge and belief of the undersigned, after due inquiry and
investigation, the following:

1.             All of the information contained in the Proxy
               Statement/Prospectus regarding Discovery and the description of
               Merger is true, correct and complete.

2.             The fair market value of the Ansan Shares and cash in lieu of
               fractional shares received by each Discovery shareholder will be
               approximately equal to the fair market value of the shares of
               Discovery Stock surrendered in the exchange.

3.             There is no plan or intention by the shareholders of Discovery
               who own one percent or more of the shares of Discovery Stock as
               of the date of the Merger, and to the best knowledge of the
               management of Discovery, there is no plan or intention on the
               part of the remaining shareholders of Discovery to sell, exchange
               or otherwise dispose of a number of Ansan Shares received in the
               Merger that would reduce Discovery shareholders' ownership of
               Ansan Shares to a number of Ansan Shares having a value, as of
               the date of the Merger, of less than 50% of the value of all of
               the formerly outstanding shares of Discovery Stock as of the same
               date.  For purposes of this representation,  (i) shares of
               Discovery Stock exchanged for cash or other property, surrendered
               by dissenters, or exchanged for cash in lieu of fractional Ansan
               Shares will be treated as outstanding shares of Discovery stock
               on the date of the Merger and (ii) shares of Discovery Stock and
               Ansan Shares held by Discovery shareholders and otherwise sold,
               redeemed, or disposed of prior or subsequent to the Merger will
               be taken into account.

4.             The payment of cash in lieu of fractional Ansan Shares is solely
               for the purpose of avoiding the expense and inconvenience to
               Ansan of issuing fractional Ansan Shares and does not represent
               separately bargained-for consideration. The total cash
               consideration that will be paid in the transaction to Discovery
               shareholders instead of issuing fractional Ansan Shares will not
               exceed one percent of the total consideration that will be
               issued in the transaction to the Discovery shareholders

 
               in exchange for their shares of Discovery Stock. The fractional
               share interests of each Discovery shareholder will be aggregated,
               and no Discovery shareholder will receive cash in an amount equal
               to or greater than the value of one full Ansan Share.

5.             Ansan will acquire at least 90 percent of the fair market value
               of the net assets and at least 70 percent of the fair market
               value of the gross assets held by Discovery immediately prior to
               the Merger.  For purposes of this representation, the following
               amounts paid, or to be paid, by Discovery in connection with the
               Merger have been treated as assets of Discovery held immediately
               prior to the Merger but not acquired by Ansan:  amounts paid, or
               to be paid, by Discovery as cash in lieu of factional shares;
               amounts paid, or to be paid, by Discovery (other than amounts
               paid, or to be paid, out of current operating income) to redeem
               Discovery stock, or as dividends on such stock; any other amounts
               paid, or to be paid, by Discovery to shareholders in the form of
               cash or other property; amounts used, or to be used, by Discovery
               to pay reorganization expenses; and amounts used, or to be used,
               by Discovery to repay or defease indebtedness.

6.             The liabilities of Discovery to be assumed by Ansan and the
               liabilities to which the transferred assets of Discovery are
               subject were incurred by Discovery in the ordinary course of its
               business.

7.             Ansan, Discovery and the shareholders of Discovery will pay their
               respective expenses, if any, incurred in connection with the
               Merger.

8.             There is no intercorporate indebtedness existing between
               Discovery and Ansan that was issued, acquired, or will be settled
               at a discount.

9.             None of the Ansan Shares to be received by any shareholder-
               employees of Discovery in the Merger will be separate
               consideration for, or allocable to, past or future services or
               any employment agreement. None of the compensation paid by
               Discovery to any shareholder-employee of Discovery is separate
               consideration for, or intended to be allocable to, such
               shareholder-employee's share of Discovery Stock, and the
               compensation paid to such shareholder-employee will be
               commensurate with amounts paid to third parties bargaining at
               arm's length for similar services.

10.            Discovery is not an investment company as defined in Section
               368(a)(2)(F)(iii) and (iv) of the Internal Revenue Code of 1986,
               as amended (the "Code").

11.            On the date of the Merger, the fair market value of the assets of
               Discovery transferred to Ansan in the Merger will equal or exceed
               the sum of liabilities assumed by Ansan, plus the amount of
               liabilities, if any, to which the transferred assets are subject.

12.            Discovery is not under the jurisdiction of a court in a "title 11
               or similar case" within the meaning of Section 368(a) (3) (A) of
               the Code.

 
13.            The Transaction Agreement, its Exhibits and Schedules, and the
               other documents referenced in the Transaction Agreement, its
               Exhibits and its Schedules represent the full and complete
               agreement among Discovery and Ansan regarding the Merger, and
               there are no other written or oral agreements regarding the
               Merger.

14.            Except for cash paid to Discovery shareholders in lieu of
               fractional shares of Ansan Shares or to Discovery shareholders
               exercising appraisal rights, no consideration other than Ansan
               Shares will be paid or received for Discovery Stock.

15.            The Merger is being undertaken for legitimate business purposes
               of Discovery and not for the purpose of reducing or avoiding
               federal income taxes.

                    IN WITNESS WHEREOF, I have, on behalf of Discovery, signed
               this Certificate as of October , 1997.

                         DISCOVERY LABORATORIES, INC.

                         By: ________________________
                              Name:
                              Title:

                                                                      Appendix 2
                                                                      ----------

                                     ANSAN
                             OFFICER'S CERTIFICATE

               In connection with the merger (the "Merger") of Discovery
Laboratories, Inc., a Delaware corporation ("Discovery") with and into Ansan
Pharmaceuticals, Inc., a Delaware corporation, pursuant to the Agreement by and
between Discovery and Ansan dated as of July 16, 1997, (the "Transaction
Agreement"; capitalized terms, unless otherwise defined herein, have the
meanings ascribed to them in the Transaction Agreement), and for purposes of the
tax opinions to be rendered by Heller Ehrman White & McAuliffe and Roberts,
Sheridan & Kotel, the undersigned officer of Ansan hereby represents on behalf
of Ansan that to the best knowledge and belief of such officer, after due
inquiry and investigation, the facts relating to the Merger, as such facts are
set forth in the Transaction Agreement and insofar as such facts pertain to
Ansan, are true, correct, and complete in all material respects.

               The undersigned further represents on behalf of Ansan that to the
best knowledge and belief of the undersigned, after due inquiry and
investigation, the following:

         1.     All of the information contained in the Proxy
                Statement/Prospectus regarding Ansan and the description of the 
                Merger is true, correct and complete.

         2.     The fair market value of the Ansan Shares and cash in lieu
                of fractional Ansan Shares received by each Discovery
                shareholder will be approximately equal to the fair market
                value of the shares of Discovery Stock surrendered in the
                exchange.

         3.     To the best knowledge of the management of Ansan, there is
                no plan or intention on the part of the shareholders of the
                Discovery to sell, exchange, or otherwise dispose of a
                number of Ansan Shares received in the Merger that would
                reduce Discovery shareholders' ownership of Ansan Shares to
                a number of Ansan Shares having a value, as of the date of
                the Merger, of less than 50% of the value of the formerly
                outstanding shares of the Discovery Stock as of the same
                date.  For purposes of this representation, (I) shares of
                Discovery stock exchanged for cash or other property,
                surrendered by dissenters, or exchanged for cash in lieu of
                fractional Ansan Shares will be treated as outstanding
                shares of Discovery Stock and shares of Ansan Stock held by
                Discovery shareholders and otherwise sold, redeemed, or
                disposed of prior or subsequent to the Merger will be
                considered in making this representation.

         4.     The payment of cash in lieu of fractional Ansan Shares is
                solely for the purpose of avoiding the expense and
                inconvenience to Ansan of issuing fractional Ansan Shares
                and does not represent separately bargained-for
                consideration.  The total cash consideration that will be paid 
                in the

 
                transaction to Discovery shareholders instead of issuing
                fractional Ansan Shares will not exceed one percent of the total
                consideration that will be issued in the transaction to the
                Discovery shareholders in exchange for their shares of Discovery
                Stock. The fractional share interests of each Discovery
                shareholder will be aggregated, and no Discovery shareholder
                will receive cash in amount equal to or greater than the value
                of one full Ansan Share.

         5.     Ansan will acquire at least 90 percent or the fair market
                value of the net assets and at least 70 percent of the fair
                market value of the gross assets held by Discovery
                immediately prior to the Merger.  For purposes of this
                representation, the following amounts paid, or to be paid,
                by Discovery in connection with the Merger have been treated
                as assets of Discovery held immediately prior to the Merger
                but not acquired by Ansan: amounts paid, or to be paid, by
                Discovery to dissenters; amounts paid, or to be paid, by
                Discovery as cash in lieu of fractional shares; amounts
                paid, or to be paid, by Discovery (other than amounts paid,
                or to be paid, out of current operating income) to redeem
                Discovery stock, or as dividends on such stock; any other
                amount paid, or to be paid, by Discovery to shareholders in
                the form of cash or other property; amounts used, or to be
                used, by Discovery to pay reorganization expenses; and
                amounts used, or to be used, by Discovery to repay or
                defease indebtedness.

         6.     Ansan has no plan or intention to reacquire any of its stock
                issued in the Merger,
 
         7.     Ansan, Discovery and the shareholders of Discovery will pay
                their respective expenses, if any, incurred in connection
                with the Merger.

         8.     There is no intercorporate indebtedness existing between
                Ansan and Discovery that was issued, acquired, or will be
                settled at a discount.

         9.     None of the Ansan Shares received by any shareholder-employees
                of Discovery in the Merger will be separate consideration for,
                or allocable to, past or future services or any employment
                agreement. None of the compensation paid by Discovery to any
                shareholder-employee of Discovery is separate consideration for,
                or intended to be allocable to, such shareholder-employee's
                shares of Discovery stock, and the compensation paid to such
                shareholder-employee will be commensurate with amounts paid to
                third parties bargaining at arm's length for similar services.

        10.     Ansan is not an investment company as defined in Section
                368(a) (2) (F) (iii) and (iv) of the Internal Revenue Code
                of 1986, as amended (the "Code").

        11.     On the date of the Merger, the fair market value of the assets
                of the Discovery transferred to Ansan in the Merger will equal
                or exceed the sum of liabilities assumed by Ansan, plus the
                amount of liabilities, if any, to which the transferred assets
                are subject.

        12.     Ansan is not under the jurisdiction of a court in a "title
                11 or similar case" within the meaning of Section 368 (a)
                (3) (A) of the Code.

        13.     Ansan has no plan or intention to sell or otherwise dispose
                of any of the assets acquired in the Merger, other than
                dispositions made in the ordinary course of business.

        14.     Ansan intends to continue the historic business of Discovery or
                use a significant portion of Discovery's historic business
                assets in a business following the Merger.

        15.     The Transaction Agreement, its Exhibits and Schedules, and
                the other documents referenced in the Transaction Agreement,
                its Exhibits and its Schedules represent the full and
                complete agreement between Ansan and Discovery regarding the
                Merger, and there are no other written or oral agreements
                regarding the Merger.

        16.     Except for cash paid to Discovery shareholders in lieu of
                fractional shares of Ansan Shares or to Discovery
                shareholders exercising appraisal rights, no consideration
                other than Ansan Shares will be paid or received for
                Discovery Stock.

        17.     The Merger is being undertaken for legitimate business
                purposes of Ansan and not for the purpose of reducing or
                avoiding federal income taxes.

                IN WITNESS WHEREOF, I have, on behalf of Ansan, signed this
                Certificate as of October    , 1997.

                                                    ANSAN PHARMACEUTICALS, INC.

                                    By:_______________________
                                      Name:
                                      Title:

 
                                                                   EXHIBIT 23.3
 
              CONSENT OF ERNST & YOUNG LLP, INDEPENDENT AUDITORS
      
  We consent to the reference to our firm under the caption "Experts" and to
the use of our report dated February 21, 1997, except as to Note 8, for which
the date is July 16, 1997, in the Proxy Statement of Ansan Pharmaceuticals,
Inc. that is made a part of Amendment No.2 to the Registration Statement
(Form S-4) and Prospectus of Ansan Pharmaceuticals, Inc. for the registration
of 8,653,122 shares of its common stock and 2,200,256 shares of its preferred
stock.     
 
                                             /s/ Ernst & Young LLP  

Palo Alto, California
October 21, 1997

                                                                  Exhibit 23.4

              [LETTERHEAD OF RICHARD A. EISNER & COMPANY, LLP]

                       CONSENT OF INDEPENDENT AUDITORS

     We hereby consent to the use in this Amendment No. 2 to the Registration
Statement on Form S-4 of our report dated February 12, 1997, on our audit of
the financial statements of Discovery Laboratories, Inc. and to the reference
to our firm under the caption "Experts" in the Registration Statement.

                                        RICHARD A. EISNER & COMPANY, LLP

                                        /s/ Richard A. Eisner & Company, LLP
                                        --------------------------------------

New York, New York
    
October 22, 1997     

                                                                   EXHIBIT 99.3A
                                                  
                CONSENT OF PERSON ABOUT TO BECOME A DIRECTOR

        I, James S. Kuo, hereby consent to the use, in the Registration
Statement on Form S-4 of Ansan Pharmaceuticals, Inc. (the "Company") to which
this consent is filed as an exhibit and the Proxy Statement/Prospectus included
therein, of my name as a person about to become a director of the Company.

                                        /s/ James S. Kuo
                                        -------------------------------------

October 21, 1997

                                                                   EXHIBIT 99.3B

                CONSENT OF PERSON ABOUT TO BECOME A DIRECTOR
 
        I, Steve H. Kanzer, hereby consent to the use, in the Registration
Statement on Form S-4 of Ansan Pharmaceuticals, Inc. (the "Company") to which
this consent is filed as an exhibit and the Proxy Statement/Prospectus included
therein, of my name as a person about to become a director of the Company. 

                                        /s/ Steve H. Kanzer 
                                        -------------------------------------

October 21, 1997

 
                                                                   EXHIBIT 99.3C

                CONSENT OF PERSON ABOUT TO BECOME A DIRECTO

        I, Evan Myrianthopoulos, hereby consent to the use, in the Registration
Statement on Form S-4 of Ansan Pharmaceuticals, Inc. (the "Company") to which
this consent is filed as an exhibit and the Proxy Statement/Prospectus included
therein, of my name as a person about to become a director of the Company.

                                        /s/ Evan Myrianthopoulos
                                        -------------------------------------

October 21, 1997

 
                                                                   EXHIBIT 99.3D

                CONSENT OF PERSON ABOUT TO BECOME A DIRECTOR

        I, Juerg F. Geigy, hereby consent to the use, in the Registration
Statement on Form S-4 of Ansan Pharmaceuticals, Inc. (the "Company") to which
this consent is filed as an exhibit and the Proxy Statement/Prospectus included
therein, of my name as a person about to become a director of the Company.

                                        /s/ Juerg F. Geigy
                                        -------------------------------------

October 21, 1997

 
                                                                   EXHIBIT 99.3E

                CONSENT OF PERSON ABOUT TO BECOME A DIRECTOR

        I, Max Link, hereby consent to the use, in the Registration Statement on
Form S-4 of Ansan Pharmaceuticals, Inc. (the "Company") to which this consent is
filed as an exhibit and the Proxy Statement/Prospectus included therein, of my
name as a person about to become a director of the Company.

                                        /s/ Max Link
                                        -------------------------------------

October 21, 1997

 
                                                                   EXHIBIT 99.3F

                CONSENT OF PERSON ABOUT TO BECOME A DIRECTOR
 
        I, Herbert H. McDade, Jr., hereby consent to the use, in the
Registration Statement on Form S-4 of Ansan Pharmaceuticals, Inc. (the
"Company") to which this consent is filed as an exhibit and the Proxy
Statement/Prospectus included therein, of my name as a person about to become a
director of the Company.

                                        /s/ Herbert H. McDade, Jr.
                                        -------------------------------------

October 21, 1997

 
                                                                   EXHIBIT 99.3G

                CONSENT OF PERSON ABOUT TO BECOME A DIRECTOR
 
        I, Mark C. Rogers, hereby consent to the use, in the Registration
Statement on Form S-4 of Ansan Pharmaceuticals, Inc. (the "Company") to which
this consent is filed as an exhibit and the Proxy Statement/Prospectus included
therein, of my name as a person about to become a director of the Company.

                                        /s/ Mark C. Rogers
                                        -------------------------------------

October 21, 1997