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                                                                     EXHIBIT 4.7

                               SECURITY AGREEMENT

         THIS SECURITY AGREEMENT (this "Agreement") made this August __, 2001
between American Biogenetic Sciences, Inc., a Delaware corporation (the
"Company") and Biotechnology Value Fund, L.P., Biotechnology Value Fund II,
L.P., Investment 10 L.L.C. and BVF Investments, L.L.C. ("Secured Parties").

SECTION 1.        SECURITY INTEREST.

         The Company hereby grants to Secured Parties a security interest (the
"Security Interest") in the Collateral, as hereafter defined. Capitalized terms
used herein without definition shall have the meanings ascribed to them in the
Revenue Participation Notes, dated as of August __, 2001 (the "Revenue
Participation Notes").

SECTION 2.        COLLATERAL.

         The property in which the Security Interest is hereby granted is the
following: (a) an undivided 25% interest in all of the Company's rights to the
payment of royalty payments under the Abbott License Agreement (the "Royalty
Rights") (B) an undivided 25% interest in all payments actually paid to the
Company on account of the Royalty Rights (the "Royalty Payments"), (C) the
account designated for the benefit of the Secured Parties under the "Trust
Account" as described in Section 4 below, and (D) the proceeds of any of the
foregoing, as "proceeds" are defined by the Uniform Commercial Code
(collectively hereafter referred to as the "Collateral").

SECTION 3.        OBLIGATIONS SECURED.

         The Security Interest shall secure the payment and performance of the
Company's obligations set forth in the Revenue Participation Notes to pay the
Secured Parties, as and when received by the Company, 25% of each of the Abbott
Royalty Payments (the "Obligations") in an amount up to the Aggregate Payment
Amount, as described in the Revenue Participation Agreement.

SECTION 4.        FINANCING STATEMENTS AND OTHER ACTION.

         (a) The Company agrees to do all acts which the Secured Parties deem
reasonably necessary or desirable to protect the Security Interest or to
otherwise carry out the provisions of this Agreement, including the execution of
financing, continuation, amendment and termination statements and other notices
appropriate under law in form satisfactory to the Company and the Secured
Parties. The Company will pay the cost of filing the same in all public offices.

         (b) The Company and the Secured Parties agree that the Form UCC-1, and
any continuation statements thereof, to be filed by the Secured Parties to
perfect the Security Interest shall be substantially in the form attached hereto
as Exhibit A.

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         (c ) All Royalty Payments shall, upon receipt by the Company, be
deposited into a separate, segregated, interest-paying account maintained by a
commercial bank insured by the FDIC (the "Trust Account"). Upon receipt, the
bank shall immediately credit 25% of such Royalty Payment to an account to be
held in trust for the benefit of Secured Parties, and shall credit 75% to an
account for the benefit of the Company. The Company may transfer the amounts
from the 75% account to itself and shall direct the bank to transfer the amounts
from the Secured Parties account to such Secured Parties in accordance with
their respective interests in the Royalty Payments in accordance with the
Revenue Participation Notes. The Trust Account shall be opened by the Company no
later than the first business day after it receives its first Royalty Payment.
Upon creation of the Trust Account, the Company shall cooperate with Secured
Parties in the creation and execution of a Control Agreement, upon such
reasonable terms as are acceptable to the bank at which the Trust Account is
maintained, so as to perfect the security interest of the Secured Parties in
their 25% account of the Trust Account.

SECTION 5.        THE COMPANY'S PLACE OF ORGANIZATION AND PLACE(S) OF BUSINESS.

         (a) The Company warrants that the Company is incorporated as a business
corporation under the laws of the State of Delaware and its exact legal name is
American Biogenetic Sciences, Inc.

         (b) The Company covenants to notify the Secured Parties of any change
in the information contained in this Section.

SECTION 6.        ENCUMBRANCES.

         (a) The Company warrants that the Company has title to the Collateral
and that there are no claims, liens, security interests or other encumbrances.

         (b) The Company covenants that it will maintain its corporate existence
in the jurisdiction specified in Section 5 and will maintain such existence in
good standing.

         (c) The Company covenants to comply with all laws and regulations of
the United States or of any state thereof or of any political subdivision
thereof, or of any governmental authority which may be applicable to it or to
its business.

SECTION 7.        MAINTENANCE OF COLLATERAL.

         The Company shall preserve the Collateral for the benefit of the
Secured Parties. Without limiting the generality of the foregoing, the Company
shall take commercially reasonable steps to collect all royalties payable by
Abbott under the Abbott License Agreement.

SECTION 8.        MAINTENANCE OF RECORDS; REPORTS.

         The Company covenants to keep at all times accurate and complete
records listing and describing the payments received from Abbott under the
Abbott License Agreement. The Secured Parties shall have the right at any time
to call at the Company's place of business and to

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inspect and to audit and make copies of any records or other writings which
relate to the Collateral.

SECTION 9.        DEFAULT.

         (a)      It shall be an Event of Default if:

                  any representation or warranty made by the Company under the
Revenue Participation Notes shall prove to have been false in any material
respect upon the date when made;

                  the Company fails to pay any amounts due under any of the
Obligations when due and such failure continues for a period of 30 days;

                  (i) the Company fails to observe or perform any covenant,
warranty or agreement to be performed by the Company under this Agreement or
the Revenue Participation Notes or any breaches any representation, warranty or
covenant relating to the Revenue Participation Notes in the Securities Purchase
Agreement, and such breach or failure continues for a period of 30 days after
the Secured Parties give written notice of such breach or failure to the
Company.

                  (ii) If an Event of Default occurs while any Obligations are
outstanding, the Secured Parties may declare the Company in default and exercise
the Rights on Default as hereinafter defined.

SECTION 10.       RIGHTS ON DEFAULT.

         (a) If an Event of a Default occurs under this Agreement, the Secured
Parties may exercise the following Rights on Default:

                  (i)  exercise the rights and remedies accorded a secured
party by the Uniform Commercial Code or by any document securing the
Obligations;

                  (ii) perform any warranty, covenant or agreement which the
Company has failed to perform under this Agreement, the Revenue Participation
Notes, or the Securities Purchase Agreement; and

                  (iii) take any other action which the Secured Parties deem
necessary or desirable to protect the Collateral or the Security Interest.

         (b) No course of dealing or delay in taking or failing to take any
other action with respect to any Event of Default shall affect the Secured
Parties' right to take such action at a later time. No waiver as to any one
Event of Default shall affect the Secured Parties' Rights on Default upon any
other Event of Default. The Secured Parties may exercise any or all of its
Rights on Default concurrently with or independently of and without regard to
the provisions of any other document which secures an Obligation.

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         (c) The requirement of the Uniform Commercial Code that the Secured
Parties give the Company reasonable notice of any proposed sale or disposition
of the Collateral shall be met if such notice is given to the Company at least
ten days before the time of such sale or disposition.

         (d) If an Event of a Default occurs under this Agreement, the present
value of the Obligations (i.e. 25% of each of the Abbott Royalty Payments, as
and when received by the Company) under the Revenue Participation Notes secured
hereby shall be determined by an independent valuation firm or appraiser
experienced in valuing such obligations such as the Secured Parties select in
good faith.

SECTION 11.       EXPENSES.

         Any payment made or expense incurred by the Secured Parties (including,
without limitation, reasonable attorneys' fees and disbursements) in connection
with the exercise of any Right on Default, shall be added to the indebtedness of
the Company to the Secured Parties, shall be payable upon demand and shall be
secured by the Security Interest.

SECTION 12.       TERM.

         The term of this Agreement shall commence on the date hereof and shall
continue in full force and effect and be binding upon the Company until all
Obligations of the Company to the Secured Parties shall have been fully paid and
satisfied.

SECTION 13.       NOTICES.

         All notices, requests, consents and other communications hereunder
shall be in writing, shall be addressed to the receiving party's address set
forth in Section 9.1 of the Securities Purchase Agreement or to such other
address as a party may designate by notice hereunder, and shall be either (i)
delivered by hand, (ii) made by telecopy or facsimile transmission, (iii) sent
by recognized national overnight courier service, or (iv) sent by registered
mail, return receipt requested, postage prepaid. All notices, requests, consents
and other communications hereunder shall be deemed to have been given either (i)
if by hand, at the time of the delivery thereof to the receiving party at the
address of such party set forth above, (ii) if made by telecopy or facsimile
transmission, one day after the time that receipt thereof has been acknowledged
by electronic confirmation or otherwise, (iii) if sent by overnight courier, on
the next business day following the day such notice is delivered to the courier
service, or (iv) if sent by registered mail, on the fifth business day following
the day such mailing is made.

SECTION 14.       ASSIGNMENT.

         This Agreement and any or all of the rights and obligations hereunder
may be assigned, delegated, sold, transferred or otherwise disposed of by the
Secured Parties by any means, including by voluntary transfer, operation of law
or otherwise, to any third person without the prior written consent of the other
parties hereto. Any such assignment, however, shall only be effective if the
assignor provides the Company with two business days' prior written notice of
such assignment. The Company's right to redeem Preferred Stock or cancel the
related Warrants pursuant to the Call Option Agreement shall survive each such
assignment, whether or not the

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related Preferred Stock or Warrant are transferred together with the transfer
of any rights under the Revenue Participation Notes or this Agreement.

SECTION 15.       GOVERNING LAW.

         This Agreement shall be governed by and construed under the laws of the
State of New York.

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         This Agreement shall have the effect of an instrument under seal.


                                   COMPANY:

                                   AMERICAN BIOGENETIC SCIENCES, INC.



                                   By:_______________________________
                                   Josef C. Schoell
                                   President

                                   SECURED PARTIES:


                                   BIOTECHNOLOGY VALUE FUND, L.P.
                                   By:  BVF PARTNERS L.P., its General Partner
                                        By: BVF, INC., its General Partner

                                            By:  ______________________________
                                                 Mark N. Lampert
                                                 President

                                   BIOTECHNOLOGY VALUE FUND II, L.P.
                                   By:  BVF PARTNERS L.P., its General Partner
                                        By: BVF, INC., its General Partner

                                            By:  ______________________________
                                                 Mark N. Lampert
                                                 President

                                   INVESTMENT 10 L.L.C.
                                   By:  BVF PARTNERS, L.P., its Investment
                                        Advisor
                                        By: BVF, INC., its General Partner

                                            By:  ______________________________
                                                 Mark N. Lampert
                                                 President

                                   BVF INVESTMENTS L.L.C.
                                   By:  BVF PARTNERS, L.P.
                                        By: BVF, INC., its General Partner

                                            By:  ______________________________
                                                 Mark N. Lampert
                                                 President


Security Agreement