EXHIBIT 2.1

CERTAIN MATERIAL (INDICATED BY AN ASTERISK) HAS BEEN OMITTED FROM THIS DOCUMENT
PURSUANT TO A REQUEST FOR CONFIDENTIAL TREATMENT. THE OMITTED MATERIAL HAS BEEN
FILED SEPARATELY WITH THE SECURITIES AND EXCHANGE COMMISSION.

                        ASSIGNMENT AND LICENSE AGREEMENT

                                 BY AND BETWEEN

                           WYETH HOLDINGS CORPORATION

                                       AND

                          NEUROCRINE BIOSCIENCES, INC.

                                FEBRUARY 26, 2004



                                TABLE OF CONTENTS



                                                                                     PAGE
                                                                                     ----
                                                                                  
1.    DEFINITIONS...............................................................      2
   1.1      "Affiliate".........................................................      2
   1.2      "Amended and Restated License Agreement"............................      2
   1.3      "Assignment and Assumption Agreement"...............................      2
   1.4      "Closing"...........................................................      2
   1.5      "Closing Date"......................................................      2
   1.6      "Compound"..........................................................      2
   1.7      "Compound License Agreement"........................................      2
   1.8      "Compound Patent"...................................................      3
   1.9      "Confidential Information"..........................................      3
   1.10     "Control" or "Controlled"...........................................      3
   1.11     "Effective Date"....................................................      3
   1.12     "HSR Act"...........................................................      3
   1.13     "HSR Filing"........................................................      3
   1.14     "HSR Clearance Date"................................................      3
   1.15     "Neurocrine Sublicense Agreement"...................................      3
   1.16     "Original License Agreement"........................................      3
   1.17     "Pfizer Collaboration Agreement"....................................      4
   1.18     "Pfizer Sublicense Agreement".......................................      4
   1.19     "Share Price".......................................................      4
   1.20     "Stock Purchase Agreement"..........................................      4
   1.21     "Territory".........................................................      4
   1.22     "Third Party".......................................................      4
   1.23     "Wyeth Intellectual Property".......................................      4
   1.24     "2002 Consent Agreement"............................................      4
   1.25     "2004 Consent Agreement"............................................      4
2.    ASSIGNMENT OF RIGHTS......................................................      5
   2.1      Assignment..........................................................      5
   2.2      Assumption..........................................................      5
   2.3      No Continuing Obligations...........................................      5
   Assignment and Assumption Agreement..........................................      6
3.    LICENSES..................................................................      6
   3.1      Exclusive License...................................................      6
   3.2      Retained Rights; No Implied Licenses................................      6
   3.3      Sublicensing........................................................      6
   3.4      Section 365(n) of the Bankruptcy Code...............................      7
4.    CONSIDERATION.............................................................      7
   4.1      Cash Payments.......................................................      7
   4.2      Equity Payment......................................................      7
   4.3      No Other Payments...................................................      8
   4.4      Taxes and Withholding...............................................      8


                                     Page i



                                                                                  
5.    THE CLOSING...............................................................      8
   5.1      Closing Date........................................................      8
   5.2      Deliveries by Neurocrine............................................      8
   5.3      Deliveries by Wyeth.................................................      9
6.    CONDITIONS and covenants..................................................     10
   6.1      Conditions to Obligations of Each Party.............................     10
   6.2      Conditions to Obligations of Wyeth..................................     10
   6.3      Conditions to Obligations of Neurocrine.............................     11
   6.4      Covenants...........................................................     11
7.    REPRESENTATIONS AND WARRANTIES............................................     11
   7.1      Representations and Warranties of Each Party........................     11
   7.2      Additional Representations and Warranties of Wyeth..................     12
   7.3      Additional Representations and Warranties by Neurocrine.............     14
   7.4      Representation by Legal Counsel.....................................     15
   7.5      No Inconsistent Agreements..........................................     15
8.    CONFIDENTIALITY...........................................................     15
   8.1      Non-Disclosure and Use Restrictions.................................     15
   8.2      SEC Filings.........................................................     16
   8.3      Public Statements...................................................     16
9.    TERM AND TERMINATION......................................................     16
   9.1      Government Approvals................................................     16
      9.1.1       HSR Filing....................................................     16
      9.1.2       Other Government Approvals....................................     17
   9.2      Termination by Mutual Agreement.....................................     17
   9.3      Termination for Cause...............................................     17
   9.4      Effects of Termination..............................................     17
10.   INDEMNIFICATION AND INSURANCE.............................................     18
   10.1     Indemnification by Neurocrine.......................................     18
   10.2     Indemnification by Wyeth............................................     19
   10.3     Procedure...........................................................     19
   10.4     Insurance...........................................................     20
   10.5     Limitation..........................................................     20
11.   MISCELLANEOUS.............................................................     20
   11.1     Assignment..........................................................     20
   11.2     Further Actions.....................................................     21
   11.3     Notices.............................................................     21
   11.4     Amendment...........................................................     22
   11.5     Waiver..............................................................     22
   11.6     Severability........................................................     22
   11.7     Descriptive Headings................................................     22
   11.8     Governing Law; Dispute Resolution...................................     22
   11.9     Entire Agreement of the Parties.....................................     23
   11.10       Independent Contractors..........................................     23
   11.11       Counterparts.....................................................     24


Exhibit 1.7       Form of Compound License Agreement

                                     Page ii


Exhibit 1.20      Form of Stock Purchase Agreement
Exhibit 1.23      Wyeth Patents
Exhibit 2.1       Form of Assignment and Assumption Agreement
Exhibit 2.4       Form of Patent Assignment
Exhibit 8.3       Press Release

                                    Page iii


                        ASSIGNMENT AND LICENSE AGREEMENT

         This Assignment and License Agreement (the "Agreement") is entered into
on this 26th day of February, 2004 (the "Signature Date") by and between Wyeth
Holdings Corporation (formerly known as "American Cyanamid Company"), a Maine
corporation, having a place of business at 5 Giralda Farms, Madison, New Jersey
07940 (hereinafter "Wyeth") and Neurocrine Biosciences, Inc., a Delaware
corporation, having a place of business at 10555 Science Center Drive, San
Diego, California 92121 (hereinafter, "Neurocrine"). Wyeth and Neurocrine may
each be referred to herein individually as a "Party" and collectively as the
"Parties".

         WHEREAS, Wyeth and DOV Pharmaceutical, Inc. (hereinafter "DOV") entered
into that certain license agreement, dated May 28, 1998 (hereinafter, the
"Original License Agreement"), pursuant to which Wyeth, inter alia, granted to
DOV an exclusive license, under certain patent rights and know-how, with respect
to several compounds, including the Compound (as defined below);

         WHEREAS, DOV and Neurocrine entered into a Sublicense and Development
Agreement dated June 30, 1998 (as amended from time to time, the "Neurocrine
Sublicense Agreement"), pursuant to which DOV sublicensed to Neurocrine the
rights relating to the Compound licensed to DOV under the Original License
Agreement;

         WHEREAS, Neurocrine and Pfizer, Inc. (hereinafter, "Pfizer") entered
into (i) that certain license agreement dated December 18, 2002 (as amended from
time to time, the "Pfizer Sublicense Agreement") pursuant to which Neurocrine,
inter alia, sublicensed to Pfizer the rights relating to the Compound licensed
to Neurocrine under the Neurocrine Sublicense Agreement and (ii) that certain
collaboration agreement dated December 18, 2002 (as amended from time to time,
the "Pfizer Collaboration Agreement") pursuant to which Neurocrine and Pfizer,
inter alia, will copromote the Compound in the United States;

         WHEREAS, Wyeth, DOV and Neurocrine entered into that certain Consent
and Agreement dated December 13, 2002 (the "2002 Consent Agreement") in order to
facilitate the grant by Neurocrine to Pfizer of certain rights under the Pfizer
Sublicense Agreement;

         WHEREAS, Neurocrine now desires to obtain from Wyeth and Wyeth now
desires to grant to Neurocrine: (i) an assignment of (x) all of Wyeth's rights
and obligations under the Compound License Agreement (as defined below), and (y)
Wyeth's rights and obligations under the 2002 Consent Agreement to the extent
such rights and obligations relate to the Compound and (z) the Compound Patent
(as defined below) and (ii) an exclusive license under the Wyeth Intellectual
Property (as defined below), to make, have made, use and sell the Compound
(which license rights are subject to the rights and licenses granted to DOV
under the Compound License Agreement);

                                  Page 1 of 24


         WHEREAS, on or before the Closing (as defined below), Wyeth and DOV
will enter into: (i) an amended and restated license agreement, pursuant to
which the Original License Agreement will be amended to delete therefrom all
rights and obligations of each of Wyeth and DOV with respect to the Compound
(the "Amended and Restated License Agreement"), and (ii) the Compound License
Agreement, setting forth the rights and obligations of each of Wyeth and DOV
solely as they relate to the Compound; and

         WHEREAS, Wyeth, DOV and Neurocrine entered into that certain Consent
Agreement and Amendment, dated February 25, 2004 (the "2004 Consent Agreement")
pursuant to which, inter alia, DOV has provided its consent for Wyeth to enter
into and perform this Agreement.

         NOW THEREFORE, in consideration of the foregoing premises and the
promises, mutual covenants and obligations set forth below, and other good and
valuable consideration, the Parties agree as follows:

1.       DEFINITIONS.

         1.1      "AFFILIATE" shall mean, with respect to any person or entity,
                  any other person or entity which controls, is controlled by or
                  is under common control with such person or entity. A person
                  or entity shall be regarded as in control of another entity if
                  it owns or controls at least fifty percent (50%) of the equity
                  securities of the subject entity entitled to vote in the
                  election of directors (or, in the case of an entity that is
                  not a corporation, for the election of the corresponding
                  managing authority), provided, however, that the term
                  "Affiliate" shall not include subsidiaries or other entities
                  in which a Party or its Affiliates owns a majority of the
                  ordinary voting power necessary to elect a majority of the
                  board of directors or other governing board, but is restricted
                  from electing such majority by contract or otherwise, until
                  such time as such restrictions are no longer in effect.

         1.2      "AMENDED AND RESTATED LICENSE AGREEMENT" shall have the
                  meaning set forth in the preamble of this Agreement.

         1.3      "ASSIGNMENT AND ASSUMPTION AGREEMENT" shall have the meaning
                  set forth in Section 2.1 hereof.

         1.4      "CLOSING" shall have the meaning set forth in Section 5.1
                  hereof.

         1.5      "CLOSING DATE" shall have the meaning set forth in Section 5.1
                  hereof.

         1.6      "COMPOUND" shall mean the chemical compound identified in the
                  License Agreement as CL 285,489, which compound is also known
                  as indiplon.

         1.7      "COMPOUND LICENSE AGREEMENT" shall mean the license agreement

                                  Page 2 of 24


                  relating solely to the Compound, which license agreement is to
                  be entered into by and between Wyeth and DOV upon their
                  amendment and restatement of the Original License Agreement as
                  described above in the preamble to this Agreement. The
                  Compound License Agreement shall be in the form attached
                  hereto as Exhibit 1.7.

         1.8      "COMPOUND PATENT" shall mean United States Patent 6,399,621
                  granted on June 4, 2002, which patent claims the Compound.

         1.9      "CONFIDENTIAL INFORMATION" shall mean, with respect to a
                  Party, all non-public proprietary data or information that is
                  disclosed by such Party to the other Party in connection with
                  this Agreement or information designated as "Confidential
                  Information" of such Party hereunder.

         1.10     "CONTROL" OR "CONTROLLED" shall mean, with respect to any (a)
                  item of information or know-how, or (b) intellectual property
                  right, the possession (whether by ownership or license, other
                  than pursuant to this Agreement) by a Party of the ability to
                  grant to the other Party access and/or a license as provided
                  herein under such item or right without violating the terms of
                  any agreement with any Third Party existing as of the date
                  such Party is obligated under this Agreement to grant such
                  access and/or license.

         1.11     "EFFECTIVE DATE" shall mean, upon completion of the Closing,
                  the Closing Date.

         1.12     "HSR ACT" shall mean the Hart-Scott-Rodino Antitrust
                  Improvements Act of 1976, as amended, and the rules and
                  regulations promulgated thereunder.

         1.13     "HSR FILING" shall mean filings by Wyeth and Neurocrine with
                  the United States Federal Trade Commission and the Antitrust
                  Division of the United States Department of Justice of a
                  Notification and Report Form for Certain Mergers and
                  Acquisitions (as that term is defined in the HSR Act) with
                  respect to the matters set forth in this Agreement and in the
                  Stock Purchase Agreement, as applicable, together with all
                  required documentary attachments thereto.

         1.14     "HSR CLEARANCE DATE" shall mean the earliest date on which the
                  Parties have actual knowledge that all applicable waiting
                  periods under the HSR Act with respect to the transactions
                  contemplated hereunder have expired or have been terminated.

         1.15     "NEUROCRINE SUBLICENSE AGREEMENT" shall have the meaning set
                  forth above in the preamble of this Agreement.

         1.16     "ORIGINAL LICENSE AGREEMENT" shall have the meaning set forth
                  above in

                                  Page 3 of 24


                  the preamble of this Agreement.

         1.17     "PFIZER COLLABORATION AGREEMENT" shall have the meaning set
                  forth above in the preamble of this Agreement.

         1.18     "PFIZER SUBLICENSE AGREEMENT" shall have the meaning set forth
                  above in the preamble of this Agreement.

         1.19     "SHARE PRICE" shall mean the price per share for common stock
                  of Neurocrine calculated in accordance with the Stock Purchase
                  Agreement.

         1.20     "STOCK PURCHASE AGREEMENT" shall mean that certain stock
                  purchase agreement to be entered into by Neurocrine and Wyeth
                  (or one of Wyeth's Affiliates designated by Wyeth) on the
                  Closing Date, which agreement shall be in the form attached
                  hereto as Exhibit 1.20.

         1.21     "TERRITORY" shall mean all countries of the world.

         1.22     "THIRD PARTY" shall mean any person or entity other than
                  Wyeth, Neurocrine or any of their respective Affiliates.

         1.23     "WYETH INTELLECTUAL PROPERTY" shall mean (a) that Wyeth
                  know-how consisting of all information, patentable or
                  otherwise, developed, applied, or acquired by Wyeth as of
                  [***] relating to the production or development of the
                  Compound, which information is reasonably useful or necessary
                  to develop or manufacture the Compound and (b) those patents
                  and patent applications Controlled by Wyeth that claim the
                  Compound or the manufacture or use thereof, which patents and
                  patent applications are listed on Exhibit 1.23 attached
                  hereto, and including all continuations,
                  continuations-in-part, divisionals, re-issues,
                  re-examinations, extensions, substitutions, patents of
                  addition, and supplementary certificates (or equivalents
                  thereof) of any such patents and patent applications and all
                  foreign counterparts thereof, in each case, only to the extent
                  that they claim or would otherwise be infringed by the
                  manufacture, use or sale of the Compound, provided, however,
                  that the Wyeth Intellectual Property shall not include the
                  Compound Patent. [***]

         1.24     "2002 CONSENT AGREEMENT" shall have the meaning set forth in
                  the preamble of this Agreement.

         1.25     "2004 CONSENT AGREEMENT" shall have the meaning set forth in
                  the preamble of this Agreement.

*** Certain information on this page has been omitted and filed separately with
the Commission. Confidential treatment has been requested with respect to the
omitted portions.

                                  Page 4 of 24


2.       ASSIGNMENT OF RIGHTS.

         2.1      ASSIGNMENT. Subject to the terms and conditions set forth in
                  this Agreement, and in consideration for the payment to be
                  made by Neurocrine to Wyeth under Section 4.1 hereof and the
                  transactions contemplated by the Stock Purchase Agreement in
                  accordance with Section 4.2 hereof, Wyeth hereby agrees to
                  assign, and shall assign at the Closing, to Neurocrine: (i)
                  all of Wyeth's rights and obligations under the Compound
                  License Agreement, and (ii) Wyeth's rights and obligations
                  under the 2002 Consent Agreement only to the extent such
                  rights and obligations relate to the Compound, and (iii) all
                  of Wyeth's right, title and interest in and to the Compound
                  Patent (all of which rights being so assigned are subject to
                  the rights and licenses granted to DOV under the Compound
                  License Agreement and granted to Neurocrine, DOV and
                  Neurocrine's sublicensee under the 2002 Consent Agreement).
                  Such assignments shall be contingent upon and become effective
                  only upon completion of the Closing and shall be made pursuant
                  to the Assignment and Assumption Agreement substantially in
                  the form attached hereto as Exhibit 2.1, to be executed and
                  delivered by the Parties and DOV at the Closing (the
                  "Assignment and Assumption Agreement").

         2.2      ASSUMPTION. Subject to the terms and conditions set forth in
                  this Agreement, Neurocrine hereby agrees to assume: (i) all of
                  Wyeth's rights and obligations under the Compound License
                  Agreement, and (ii) Wyeth's rights and obligations under the
                  2002 Consent Agreement only to the extent such rights and
                  obligations relate to the Compound. Additionally, Neurocrine
                  as of the Closing and thereafter shall have the sole and
                  exclusive right, at its own expense, for the continued
                  maintenance and enforcement of the Compound Patent, subject
                  only to the obligations so assumed by Neurocrine and the
                  rights and licenses granted to DOV under the Compound License
                  Agreement. Neurocrine's assumption of such rights and
                  obligations shall be contingent upon and become effective only
                  upon completion of the Closing and shall be made pursuant to
                  the Assignment and Assumption Agreement.

         2.3      NO CONTINUING OBLIGATIONS. Neurocrine agrees that, upon
                  completion of the Closing and thereafter, Wyeth shall have no
                  further or continuing rights or obligations (a) with respect
                  to the Compound Patent, (b) under the Compound License
                  Agreement, or (c) under the 2002 Consent Agreement, to the
                  extent that any such obligations relate solely to the
                  Compound. Notwithstanding the foregoing, Wyeth agrees that it
                  will at all times remain obligated under the 2002 Consent
                  Agreement as and only to the extent that Wyeth is and remains
                  the owner and licensor (to Neurocrine, DOV or Neurocrine's
                  Approved Sublicensee) of the Wyeth Know-How and Wyeth Patents
                  (as such terms are defined in the Compound License Agreement,
                  but not including the Compound Patent).

                                  Page 5 of 24


         2.4      ASSIGNMENT AND ASSUMPTION AGREEMENT. On the Effective Date or
                  such later date as may be mutually agreed to by the Parties,
                  Wyeth, after having received the payment due from Neurocrine
                  under Section 4.1 and the shares of Neurocrine common stock
                  and payments to be transferred and delivered to Wyeth in
                  accordance with Section 4.2 hereof and the Stock Purchase
                  Agreement, shall execute and deliver to Neurocrine the
                  Assignment and Assumption Agreement. Additionally, at such
                  time, Wyeth shall execute and deliver to Neurocrine the Patent
                  Assignment, substantially in the form attached hereto as
                  Exhibit 2.4 (the "Patent Assignment") and such other documents
                  that Neurocrine may reasonably require in order to record the
                  assignment to Neurocrine of the Compound Patent in the U.S.
                  Patent Office and/or any foreign patent office and to record
                  the assignment to Neurocrine of the Compound License Agreement
                  and/or the 2002 Consent Agreement in any governmental office
                  and/or as otherwise necessary or useful to perfect the rights
                  being assigned to Neurocrine hereunder.

3.       LICENSES.

         3.1      EXCLUSIVE LICENSE. Effective as of, and only upon, the
                  completion of the Closing, Wyeth hereby grants to Neurocrine
                  an exclusive, fully-paid, royalty free, perpetual, irrevocable
                  license under the Wyeth Intellectual Property, solely to make,
                  have made, use, import, offer for sale and/or sell
                  pharmaceutical products containing the Compound in the
                  Territory subject to the licenses granted to DOV pursuant to
                  the Compound License Agreement.

         3.2      RETAINED RIGHTS; NO IMPLIED LICENSES. Except for the license
                  expressly granted to Neurocrine in Section 3.1 above, Wyeth
                  retains all right, title and interest under the Wyeth
                  Intellectual Property and shall have the right to practice and
                  use the Wyeth Intellectual Property for any purpose without
                  any obligation to Neurocrine, subject to the rights and
                  licenses granted by Wyeth to DOV under the Compound License
                  Agreement and by Wyeth to DOV, Neurocrine and/or Neurocrine's
                  sublicensee under the 2002 Consent Agreement. The Parties
                  expressly agree that, under this Agreement, Neurocrine shall
                  have no right, title or interest, either express or implied,
                  in or to any patent, patent application or other intellectual
                  property right owned or controlled by Wyeth or any of Wyeth's
                  Affiliates, except for the license rights expressly granted in
                  Section 3.1 above.

         3.3      SUBLICENSING. Subject to and to the extent not in
                  contravention of the rights and licenses granted to DOV under
                  the Compound License Agreement, Neurocrine may grant to one or
                  more Third Parties sublicenses of the rights granted to it
                  under Section 3.1 hereof at any time. Each such sublicense
                  shall be subject and subordinate to, and consistent with, the
                  terms and conditions of this Agreement, and shall provide that
                  any such sublicensee shall not further sublicense except on
                  terms

                                  Page 6 of 24


                  consistent with this Section 3.3. Neurocrine shall provide
                  Wyeth with a copy of any sublicense granted pursuant to this
                  Section 3.3 within thirty (30) days after the execution
                  thereof. Neurocrine shall remain responsible for the
                  performance of its sublicensees, and shall ensure that any
                  such sublicensees comply with the relevant provisions of this
                  Agreement.

         3.4      SECTION 365(n) OF THE BANKRUPTCY CODE. All rights and licenses
                  granted under or pursuant to any Section of this Agreement
                  are, and shall otherwise be deemed to be, for purposes of
                  Section 365(n) of the Bankruptcy Code, licenses of rights to
                  "intellectual property" as defined under Section 101 (35A) of
                  the Bankruptcy Code. The Parties shall retain and may fully
                  exercise all of their respective rights and elections under
                  the Bankruptcy Code.

4.       CONSIDERATION.

         4.1      CASH PAYMENTS. In partial consideration for the rights and
                  obligations assigned to Neurocrine under Article 2 hereof and
                  the licenses granted to Neurocrine under Article 3 hereof, and
                  subject to the terms and conditions of this Agreement,
                  Neurocrine shall pay to Wyeth :

                  (a)      the non-creditable sum of Five Million Dollars
                           ($5,000,000.00) (the "Initial Fee"), which amount
                           shall be payable within two (2) business days of the
                           Signature Date and shall be non-refundable except as
                           otherwise expressly set forth in Section 9.4 hereof;
                           and

                  (b)      the non-refundable, non-creditable sum of Forty-Five
                           Million Dollars ($45,000,000.00) which amount shall
                           be payable at the Closing.

                  Such payments shall be made in United States Dollars by wire
                  transfer of immediately available funds to a bank account of
                  Wyeth or one of Wyeth's Affiliates, which bank account is
                  designated in writing by Wyeth to Neurocrine.

         4.2      EQUITY PAYMENT. In further consideration for the rights and
                  obligations assigned to Neurocrine under Article 2 hereof and
                  the licenses granted to Neurocrine under Article 3 hereof,
                  Neurocrine, at the Closing and in accordance with the terms
                  and conditions of the Stock Purchase Agreement, shall
                  irrevocably transfer and deliver to Wyeth or, at Wyeth's
                  election, one of Wyeth's Affiliates, (i) that number of shares
                  of Neurocrine common stock that, based on the Share Price, has
                  a value of Forty-Five Million Dollars ($45,000,000.00), as
                  such amount may be adjusted in accordance with the terms and
                  conditions of the Stock Purchase Agreement and (ii) if
                  applicable, that amount of cash which may be due in accordance
                  with the terms and conditions of the Stock Purchase Agreement
                  as a result of any adjustment made to the number of shares of

                                  Page 7 of 24


                  Neurocrine common stock to be transferred and delivered to
                  Wyeth pursuant to the Stock Purchase Agreement.

         4.3      NO OTHER PAYMENTS. Upon receipt by Wyeth of the payment
                  required under Section 4.1 above and the Neurocrine common
                  stock to be delivered to Wyeth in accordance with Section 4.2
                  above and the terms and conditions of the Stock Purchase
                  Agreement, Neurocrine, except as provided in Article 10 below,
                  shall have no further obligation to make any payments to Wyeth
                  in connection with the assignment of rights and obligations
                  hereunder, the grant of licenses to Neurocrine hereunder
                  and/or the development and/or commercialization of the
                  Compound or pharmaceutical products containing the Compound,
                  and the licenses granted to Neurocrine under Section 3.1 shall
                  thereafter be fully paid up and royalty free.

         4.4      TAXES AND WITHHOLDING. All payments under this Agreement will
                  be made without any deduction or withholding for or on account
                  of any tax unless such deduction or withholding is required by
                  applicable laws or regulations. If Neurocrine is so required
                  to deduct or withhold, Neurocrine will (a) promptly notify
                  Wyeth of such requirement, (b) pay to the relevant authorities
                  the full amount required to be deducted or withheld promptly
                  upon the earlier of determining that such deduction or
                  withholding is required or receiving notice that such amount
                  has been assessed against Wyeth, and (c) promptly forward to
                  Wyeth an official receipt (or certified copy) or other
                  documentation reasonably acceptable to Wyeth evidencing such
                  payment to such authorities.

5.       THE CLOSING.

         5.1      CLOSING DATE. Unless this Agreement shall have been earlier
                  terminated, the closing of the transactions contemplated
                  hereby (the "Closing") shall take place at the offices of
                  Wyeth Pharmaceuticals, 500 Arcola Road, Collegeville,
                  Pennsylvania 19426 on the later of March 15, 2004 or the
                  second business day after the date on which the last to be
                  fulfilled or waived of the conditions set forth in Article 6
                  shall be fulfilled or waived in accordance with this Agreement
                  or at such other time, date or place as the Parties may
                  mutually agree upon in writing (the "Closing Date"). At the
                  Closing, the Parties will exchange funds, certificates and
                  other documents specified in this Agreement. For purposes of
                  this Agreement, the Closing will be treated as if it occurred
                  at 11:59 p.m. EST on the Closing Date.

         5.2      DELIVERIES BY NEUROCRINE. On the Closing Date, Neurocrine
                  shall deliver to Wyeth the following:

                  (a)      the Stock Purchase Agreement duly executed by
                           Neurocrine;

                                  Page 8 of 24


                  (b)      the payment due to Wyeth under Section 4.1(b) of this
                           Agreement;

                  (c)      a stock certificate representing the number of shares
                           of Neurocrine common stock to be delivered to Wyeth
                           or Wyeth's Affiliate pursuant to the Stock Purchase
                           Agreement and Section 4.2 above;

                  (d)      all payments that may be required to be paid by
                           Neurocrine to Wyeth under the Stock Purchase
                           Agreement in connection with any adjustment to be
                           made to the number of shares of Neurocrine common
                           stock to be transferred and delivered to Wyeth
                           thereunder;

                  (e)      the Assignment and Assumption Agreement duly signed
                           by an authorized officer of Neurocrine and such other
                           instruments of assumption and other certificates,
                           instruments or documents, in form and substance
                           reasonably acceptable to Wyeth and Neurocrine, as may
                           be required under this Agreement or as may otherwise
                           be necessary to effect Neurocrine's assumption under
                           applicable laws of the rights and obligations and
                           other assets being assigned and/or licensed to
                           Neurocrine under this Agreement;

                  (f)      such other instruments and documents, in form and
                           substance reasonably acceptable to Wyeth and
                           Neurocrine, as may be necessary to effect the
                           Closing; and

                  (g)      a certificate, executed by an authorized officer of
                           Neurocrine, certifying (i) the due organization and
                           good standing of Neurocrine, and (ii) the authority
                           and incumbency of officers of Neurocrine executing
                           this Agreement and the other agreements, instruments
                           and certificates delivered by Neurocrine to Wyeth
                           upon the Closing.

         5.3      DELIVERIES BY WYETH. On the Closing Date, Wyeth shall deliver
                  to Neurocrine the following:

                  (a)      the Stock Purchase Agreement duly executed by Wyeth
                           (or an Affiliate of Wyeth designated by Wyeth);

                   (b)     the Assignment and Assumption Agreement duly executed
                           by an authorized officer of Wyeth, and any other
                           appropriate instruments of assignment, sale,
                           conveyance or transfer, in form and substance
                           reasonably acceptable to Wyeth and Neurocrine, as may
                           be required under this Agreement or as may otherwise
                           be necessary to effect Wyeth's assignment under
                           applicable laws of the rights and obligations and
                           other assets being assigned and/or licensed to
                           Neurocrine under this Agreement;

                                  Page 9 of 24


                  (c)      the Patent Assignment duly executed by an authorized
                           officer of Wyeth;

                  (d)      such other instruments and documents, in form and
                           substance reasonably acceptable to Wyeth and
                           Neurocrine, as may be necessary to effect the
                           Closing; and

                  (e)      a certificate, executed by an authorized officer of
                           Wyeth, certifying (i) the due organization and good
                           standing of Wyeth, and (ii) the authority and
                           incumbency of officers of Wyeth executing this
                           Agreement and the other agreements, instruments and
                           certificates delivered by Wyeth to Neurocrine upon
                           the Closing.

6.       CONDITIONS AND COVENANTS.

         6.1      CONDITIONS TO OBLIGATIONS OF EACH PARTY. The obligation of
                  each Party to enter into and effect the transactions
                  contemplated by this Agreement shall be subject to the
                  fulfillment at or prior to the Closing Date of the following
                  conditions:

                  (a)      all consents and approvals of governmental
                           authorities, if any, necessary to permit the
                           consummation of the transactions contemplated by this
                           Agreement shall have been obtained and any waiting
                           period (including any extension thereof) applicable
                           to the consummation of this Agreement under the HSR
                           Act shall have expired or been terminated; and

                  (b)      no preliminary or permanent injunction or other
                           order, decree or ruling issued by a court of
                           competent jurisdiction or by a governmental authority
                           or executive order promulgated or enacted by any
                           governmental authority shall be in effect that would
                           restrain or otherwise prevent the entry into or the
                           consummation of the transactions contemplated by this
                           Agreement.

         6.2      CONDITIONS TO OBLIGATIONS OF WYETH. The obligation of Wyeth to
                  effect the transactions contemplated by Sections 5.1 and 5.3
                  of this Agreement is subject to the fulfillment at or prior to
                  the Closing Date of the following conditions:

                  (a)      Neurocrine and DOV shall have duly executed and
                           delivered the 2004 Consent Agreement which shall be
                           in full force and effect as of the Closing Date;

                  (b)      Wyeth shall have received all necessary approvals
                           from its Board of Directors to effect the
                           transactions contemplated by this Agreement;

                                  Page 10 of 24


                  (c)      Neurocrine shall have made the payments contemplated
                           under Section 4.1 hereof, delivered those shares of
                           Neurocrine common stock and other payments to be
                           delivered to Wyeth in accordance with the provisions
                           of the Stock Purchase Agreement and delivered to
                           Wyeth all other documents and deliverables to be
                           delivered by Neurocrine to Wyeth at or before the
                           Closing in accordance with Section 5.2 hereof;

                   (d)     Neurocrine shall have executed and delivered to
                           Wyeth, the Assignment and Assumption Agreement;
                           and(c)Neurocrine shall have duly executed and
                           delivered the Stock Purchase Agreement to be entered
                           into by the Parties on the Closing Date and shall
                           have met all other conditions and obligations
                           required of Neurocrine under the Stock Purchase
                           Agreement.

         6.3      CONDITIONS TO OBLIGATIONS OF NEUROCRINE. The obligation of
                  Neurocrine to enter into and effect the transactions
                  contemplated by Sections 5.1 and 5.2 of this Agreement is
                  subject to the fulfillment at or prior to the Closing Date of
                  the following conditions:

                  (a)      Wyeth and DOV shall have duly executed and delivered
                           the Compound License Agreement and the 2004 Consent
                           Agreement, each of which shall be in full force and
                           effect as of the Closing Date;

                  (b)      Wyeth shall have executed and delivered to Neurocrine
                           the Assignment and Assumption Agreement and the
                           Patent Assignment;

         6.4      COVENANTS. Each Party covenants and agrees to use diligent,
                  good faith efforts to fulfill or cause to be fulfilled each of
                  the conditions set forth above with respect to its effecting
                  the transactions contemplated by Article 5 of this Agreement,
                  at or prior to the Closing Date.

7.       REPRESENTATIONS AND WARRANTIES.

         7.1      REPRESENTATIONS AND WARRANTIES OF EACH PARTY. Each of
                  Neurocrine and Wyeth hereby represents, warrants, and
                  covenants to the other Party hereto as follows:

                  (a)      it is a corporation or entity duly organized and
                           validly existing under the laws of the state or other
                           jurisdiction of its incorporation or formation;

                  (b)      the execution, delivery and performance of this
                           Agreement and of the Stock Purchase Agreement by such
                           Party has been duly authorized by all requisite
                           corporate action and does not require any shareholder
                           action or approval, provided, however, that

                                  Page 11 of 24


                           Neurocrine acknowledges that Wyeth is required to
                           seek and obtain approval of its Board of Directors in
                           order to complete the transactions contemplated this
                           Agreement and that obtaining such approval is a
                           condition to Wyeth's obligations hereunder;

                  (c)      it has the power and authority to execute and deliver
                           this Agreement and the Stock Purchase Agreement and
                           to perform its obligations hereunder and thereunder;

                  (d)      the execution, delivery and performance by such Party
                           of this Agreement and the Stock Purchase Agreement
                           and its compliance with the terms and provisions
                           hereof and thereof does not and will not conflict
                           with or result in a breach of any of the terms and
                           provisions of or constitute a default under (i) a
                           loan agreement, guaranty, financing agreement,
                           agreement affecting a product or other agreement or
                           instrument binding or affecting it or its property;
                           (ii) the provisions of its charter or operative
                           documents or bylaws; or (iii) any order, writ,
                           injunction or decree of any court or governmental
                           authority entered against it or by which any of its
                           property is bound;

                  (e)      it shall at all times comply with all applicable laws
                           and regulations relating to its activities under this
                           Agreement and the Stock Purchase Agreement; and

                  (f)      There is no action, demand, suit, proceeding,
                           arbitration, grievance, citation, summons, subpoena,
                           inquiry or investigation of any nature, civil,
                           criminal, regulatory or otherwise, in law or in
                           equity, pending or, to such Party's knowledge,
                           threatened against such Party with respect to this
                           Agreement, the License Agreement, the 2002 Consent
                           Agreement or the Compound Patent.

         7.2      ADDITIONAL REPRESENTATIONS AND WARRANTIES OF WYETH. In
                  addition to the representations and warranties made by Wyeth
                  in Section 7.1 above and Sections 7.4 and 7.5 below, Wyeth
                  hereby represents, warrants, and covenants to Neurocrine that

                  (a)      as of the Effective Date of this Agreement, the 2004
                           Consent Agreement will be in full force and effect
                           and that, to Wyeth's knowledge, neither Wyeth nor DOV
                           will have committed any material breach thereunder
                           which material breach remains uncured and would give
                           rise to a right of either Neurocrine, Wyeth or DOV to
                           terminate the 2004 Consent Agreement;

                  (b)      as of the Effective Date of this Agreement, the
                           Compound License Agreement will be in full force and
                           effect and that, to Wyeth's knowledge, neither Wyeth
                           nor DOV will have committed any

                                  Page 12 of 24


                           material breach thereunder which material breach
                           remains uncured and would give rise to a right of
                           either Wyeth or DOV to terminate the Compound License
                           Agreement; except for the rights and licenses granted
                           to DOV under the Compound License Agreement and the
                           rights and licenses granted to Neurocrine and
                           Neurocrine's sublicensees under the 2002 Consent
                           Agreement, Wyeth, as of the Effective Date of this
                           Agreement, will not have granted to any Third Party
                           any right, title or interest in or to the Compound
                           Patent or the Wyeth Intellectual Property in so far
                           as it relates to the Compound;

                  (c)      Except as set forth in (i) the 2002 Consent
                           Agreement, (ii) the 2004 Consent Agreement, (iii) the
                           Amended and Restated License Agreement and (iv) the
                           Compound License Agreement, the Original License
                           Agreement has not been amended, modified or
                           supplemented in any way since its effective date,
                           insofar as it relates to the Compound or the Wyeth
                           Intellectual Property in so far as it relates to
                           Compound;

                  (d)      to Wyeth's actual knowledge, without having made or
                           having any duty to make any inquiry, as of the
                           Signature Date there is no written safety or other
                           information in Wyeth's possession relating the
                           Compound per se, which information (i) has not been
                           previously disclosed by Wyeth to DOV and/or
                           Neurocrine, and (ii) in Wyeth's reasonable
                           determination, would have a material adverse effect
                           on the development of the Compound;

                  (e)      to Wyeth's actual knowledge, without having made or
                           having any duty to make any inquiry, as of the
                           Signature Date, (i) the issued patents within the
                           Wyeth Intellectual Property and the Compound Patent
                           are valid and enforceable, (ii) no third party is
                           infringing any issued patents within the Wyeth
                           Intellectual Property or the Compound Patent through
                           the manufacture, use or sale of the Compound and
                           (iii) no third party owns or controls any patent, or
                           assuming issuance of the claims as filed therein, any
                           patent application, which claims the manufacture, use
                           and sale of Compound per se (for the sake of clarity,
                           this representation and warranty does not extend to
                           any pharmaceutical formulation of the Compound or any
                           general manufacturing or process technology which may
                           be used by Neurocrine or its sublicensees in
                           connection with the Compound); and

                  (f)      to Wyeth's actual knowledge, without having made or
                           having any duty to make any inquiry, as of the
                           Signature Date there are no patents owned or licensed
                           by Wyeth or any of its Affiliates that would be
                           infringed by the making, using or selling the
                           Compound per se by Neurocrine or its sublicensees,
                           provided, however, that

                                  Page 13 of 24


                           this representation and warranty does not and shall
                           not extend to any patents which may cover Wyeth's
                           general manufacturing or process technology or
                           pharmaceutical product formulation technology.

                  EXCEPT AS EXPRESSLY SET FORTH IN THIS ARTICLE 7, WYETH MAKES
                  NO REPRESENTATION OR WARRANTY OF ANY KIND, EITHER EXPRESS OR
                  IMPLIED, TO NEUROCRINE, INCLUDING, WITHOUT LIMITATION, ANY
                  EXPRESS OR IMPLIED WARRANTY WITH RESPECT TO THE COMPOUND, THE
                  COMPOUND PATENT, THE WYETH INTELLECTUAL PROPERTY, THE
                  POTENTIAL AMOUNT OF PAYMENTS TO BE RECEIVED BY WYETH FROM DOV
                  UNDER THE COMPOUND LICENSE AGREEMENT OR WYETH'S OR DOV'S PAST
                  AND FUTURE PERFORMANCE UNDER THE ORIGINAL LICENSE AGREEMENT,
                  THE COMPOUND LICENSE AGREEMENT OR THE 2002 CONSENT AGREEMENT.
                  IN ADDITION TO BUT NOT IN LIMITATION OF THE FOREGOING, AND
                  EXCEPT AS EXPRESSLY PROVIDED OTHERWISE IN THIS AGREEMENT,
                  WYETH SPECIFICALLY DISCLAIMS (i) ANY EXPRESS OR IMPLIED
                  WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR
                  PURPOSE WITH RESPECT TO THE COMPOUND OR ANY PHARMACEUTICAL
                  PRODUCT CONTAINING THE COMPOUND, (ii) ANY EXPRESS OR IMPLIED
                  WARRANTY REGARDING THE TITLE, VALIDITY OR ENFORCEABILITY OF
                  THE COMPOUND PATENT OR ANY PATENT OR OTHER INTELLECTUAL
                  PROPERTY RIGHT INCLUDED IN THE WYETH INTELLECTUAL PROPERTY,
                  AND (iii) ANY EXPRESS OR IMPLIED WARRANTY THAT THE
                  DEVELOPMENT, MANUFACTURE, USE, DISTRIBUTION, MARKETING,
                  PROMOTION OR SALE OF THE COMPOUND OR ANY PHARMACEUTICAL
                  PRODUCT CONTAINING THE COMPOUND BY OR ON BEHALF OF DOV,
                  NEUROCRINE OR ANY OF THEIR RESPECTIVE LICENSEES OR
                  SUBLICENSEES WILL NOT INFRINGE ANY PATENT OR OTHER
                  INTELLECTUAL PROPERTY RIGHT OF ANY THIRD PARTY OR ANY PATENT
                  OR OTHER INTELLECTUAL PROPERTY OF WYETH OR ANY OF WYETH'S
                  AFFILIATES, WHICH PATENT OR OTHER INTELLECTUAL PROPERTY RIGHT
                  IS NOT INCLUDED IN EITHER THE COMPOUND PATENT OR THE WYETH
                  INTELLECTUAL PROPERTY.

         7.3      ADDITIONAL REPRESENTATIONS AND WARRANTIES BY NEUROCRINE. In
                  addition to the representations and warranties made by
                  Neurocrine in Section 7.1 above and Sections 7.4 and 7.5
                  below, Neurocrine hereby represents, warrants, and covenants
                  to Wyeth that

                                  Page 14 of 24


                  (a)      as of the Effective Date of this Agreement, the 2004
                           Consent Agreement will be in full force and effect
                           and that, to Neurocrine's knowledge, neither
                           Neurocrine nor DOV will have committed any material
                           breach thereunder which material breach remains
                           uncured and would give rise to a right of either
                           Neurocrine, Wyeth or DOV to terminate the 2004
                           Consent Agreement;

                  (b)      as of the Effective Date of this Agreement it will
                           have sufficient funds available to fulfill its
                           payment obligations under this Agreement;

                  (c)      except as set forth in the 2002 Consent Agreement and
                           the 2004 Consent Agreement, the Neurocrine Sublicense
                           Agreement has not been amended, modified or
                           supplemented in any way since its effective date.

         7.4      REPRESENTATION BY LEGAL COUNSEL. Each Party hereto represents
                  that it has been represented by legal counsel in connection
                  with this Agreement and acknowledges that it has participated
                  in the drafting hereof. In interpreting and applying the terms
                  and provisions of this Agreement, the Parties agree that no
                  presumption shall exist or be implied against the Party which
                  drafted such terms and provisions.

         7.5      NO INCONSISTENT AGREEMENTS. Except for the Compound License
                  Agreement and the 2002 Consent Agreement, to each of which
                  Wyeth is a party and under each of which Wyeth requires and
                  has obtained DOV's consent to enter into this Agreement, as of
                  the Effective Date of this Agreement neither Party has in
                  effect nor shall enter into any oral or written agreement or
                  arrangement that is inconsistent with its obligations under
                  this Agreement.

8.       CONFIDENTIALITY.

         8.1      NON-DISCLOSURE AND USE RESTRICTIONS. Except to the extent
                  expressly authorized by this Agreement or otherwise agreed in
                  writing, the Parties agree that, for the term of this
                  Agreement and for five (5) years thereafter, each Party (the
                  "Receiving Party") receiving any Confidential Information of
                  the other Party (the "Disclosing Party") hereunder shall keep
                  such Confidential Information confidential and shall not
                  publish or otherwise disclose or use such Confidential
                  Information for any purpose other than as provided for in this
                  Agreement except for Confidential Information that the
                  Receiving Party can establish

                  (a)      was already known by the Receiving Party (other than
                           under an obligation of confidentiality), at the time
                           of disclosure by the Disclosing Party and such
                           Receiving Party has documentary evidence to that
                           effect;

                                  Page 15 of 24


                  (b)      was generally available to the public or otherwise
                           part of the public domain at the time of its
                           disclosure to the Receiving Party;

                  (c)      became generally available to the public or otherwise
                           part of the public domain after its disclosure or
                           development, as the case may be, and other than
                           through any act or omission of a Party in breach of
                           this confidentiality obligation;

                  (d)      was disclosed to that Party, other than under an
                           obligation of confidentiality, by a Third Party who
                           had no obligation to the Disclosing Party not to
                           disclose such information to others; or

                  (e)      was independently discovered or developed by or on
                           behalf of the Receiving Party without the use of the
                           Confidential Information belonging to the other Party
                           and the Receiving Party has documentary evidence to
                           that effect.

         8.2      SEC FILINGS. Either Party may disclose the terms of this
                  Agreement to the extent required, in the reasonable opinion of
                  such Party's legal counsel, to comply with applicable laws,
                  including, without limitation, the rules and regulations
                  promulgated by the United States Securities and Exchange
                  Commission (the "SEC"). Notwithstanding the foregoing, before
                  disclosing this Agreement or any of the terms hereof pursuant
                  to this Section 8.2, the Parties will consult with one another
                  on the terms of this Agreement to be redacted in making any
                  such disclosure. If a Party discloses this Agreement or any of
                  the terms hereof in accordance with this Section 8.2, such
                  Party agrees, at its own expense, to seek confidential
                  treatment of portions of this Agreement or such terms, as may
                  be reasonably requested by the other Party.

         8.3      PUBLIC STATEMENTS. So long as this Agreement is in effect,
                  neither of the Parties hereto shall issue or cause the
                  dissemination of any press release or other announcement with
                  respect to this Agreement or the transactions contemplated
                  hereby without consulting with and obtaining the consent of
                  the other Party which consent shall not be unreasonably
                  withheld; provided, however, that such consent shall not be
                  required where such release or announcement is required by
                  applicable law or legal process. The Parties agree that the
                  press release attached hereto as Exhibit 8.3 may be released
                  on or after the Effective Date or such earlier date as may be
                  required by applicable law.

9.       TERM AND TERMINATION.

         9.1      GOVERNMENT APPROVALS.

                  9.1.1    HSR FILING. To the extent necessary and to the extent
                           not already done so prior to the Signature Date, each
                           of Neurocrine and Wyeth shall, as soon as reasonably
                           practicable after the Signature Date,

                                  Page 16 of 24


                           but in no event later than five (5) business days
                           after the Signature Date, file with the United States
                           Federal Trade Commission and the Antitrust Division
                           of the United States Department of Justice, any HSR
                           Filing required of it in the reasonable opinion of
                           both Parties under the HSR Act with respect to the
                           transactions contemplated hereby. The Parties shall
                           cooperate with one another to the extent necessary in
                           the preparation of any such HSR Filing. Each Party
                           shall be responsible for its own costs, expenses, and
                           filing fees associated with any HSR Filing, provided,
                           however, that, except as expressly set forth in
                           Section __ below, Neurocrine shall be solely
                           responsible for any fees required to be paid to any
                           government agency in connection with making any such
                           HSR Filing.

                  9.1.2    OTHER GOVERNMENT APPROVALS. To the extent not
                           otherwise addressed in Section 9.1.1 above,
                           Neurocrine and Wyeth will cooperate and use
                           respectively all reasonable efforts to make all
                           registrations, filings and applications, to give all
                           notices and to obtain as soon as practicable all
                           governmental or other consents, transfers, approvals,
                           orders, qualifications authorizations, permits and
                           waivers, if any, and to do all other things necessary
                           or desirable for the consummation of the transactions
                           as contemplated hereby.

         9.2      TERMINATION BY MUTUAL AGREEMENT. This Agreement may be
                  terminated at any time by mutual written agreement of the
                  Parties.

         9.3      TERMINATION FOR CAUSE. This Agreement may be terminated at any
                  time prior to the Closing Date:

                  (a)      by Wyeth if the Closing shall not have occurred on or
                           prior to March 31, 2004;

                  (b)      by Neurocrine if the Closing shall not have occurred
                           on or prior to March 31, 2004; or

                  (c)      subject to Section 9.1, by Wyeth or Neurocrine if a
                           court of competent jurisdiction or governmental
                           authority shall have issued an order, decree or
                           ruling or taken any other action, in each case
                           permanently restraining, enjoining or otherwise
                           prohibiting the transactions contemplated by this
                           Agreement, and such order, decree, ruling or other
                           action shall have become final and nonappealable.

         9.4      EFFECTS OF TERMINATION. Upon expiration or termination of this
                  pursuant to this Article 9, (a) this Agreement shall forthwith
                  become null and void, except that nothing herein shall relieve
                  any Party from liability for breach

                                  Page 17 of 24


                  of this Agreement prior to such termination. Upon termination
                  of this Agreement for any reason other than Neurocrine's
                  failure to meet one or more of the conditions set forth in
                  Section 6.2 , Wyeth shall refund to Neurocrine the Initial Fee
                  (without interest) within thirty (30) days following such
                  termination. Additionally, if this Agreement is terminated as
                  a result of a failure to meet the condition set forth in
                  Section 6.2(b), Wyeth, within thirty (30) days of such
                  termination, shall reimburse Neurocrine the amount of any fees
                  actually paid by Neurocrine to any government agency in
                  connection with the making of any HSR Filing pursuant to
                  Section 9.1.1 above, provided, however, the maximum amount
                  that Wyeth shall be obligated to so reimburse Neurocrine shall
                  be forty-five thousand dollars ($45,000). Notwithstanding the
                  foregoing, this Article 9, Articles 8 and 10 and Sections
                  4.1(a), 11.3, and 11.8 of this Agreement shall survive any
                  such expiration or termination.

10.      INDEMNIFICATION AND INSURANCE.

         10.1     INDEMNIFICATION BY NEUROCRINE. Neurocrine will indemnify,
                  defend and hold harmless Wyeth, Wyeth's Affiliates, and each
                  of its and their respective employees, officers, directors and
                  agents (each, a "Wyeth Indemnified Party") from and against
                  any and all liability, loss, damage, expense (including
                  reasonable attorneys' fees and expenses) and cost
                  (collectively, a "Liability") that the Wyeth Indemnified Party
                  may be required to pay to one or more Third Parties resulting
                  from or arising out of or in connection with any Third Party
                  claims of any nature arising out of:

                  (a)      the research, development, manufacture or
                           commercialization of the Compound or any
                           pharmaceutical product containing the Compound by, on
                           behalf of, or under the authority of Neurocrine, its
                           Affiliates, and its or their licensees or
                           sublicensees, and their further licensees or
                           sublicensees including, without limitation, Pfizer
                           and any of Pfizer's Affiliates, sublicensees,
                           contractors or commercialization partners;

                  (b)      any Neurocrine representation or warranty set forth
                           herein being untrue in any material respect when
                           made;

                  (c)      any breach or other action taken or omission made by
                           or on behalf of Neurocrine or any of Neurocrine's
                           Affiliates under the Compound License Agreement or
                           the 2002 Consent Agreement; and/or

                  (d)      any action taken or failure to act by Neurocrine, its
                           Affiliates, any of their respective licensees or
                           sublicensees (including, without

                                  Page 18 of 24


                           limitation, Pfizer and Pfizer's Affiliates) and any
                           of their further licensees or sublicensees, in
                           connection with the filing, prosecution, maintenance
                           or enforcement of the Compound Patent, whether such
                           action or failure to act occurred prior to or after
                           the Effective Date of this Agreement;

                  except in each case, to the extent caused by the negligence or
                  willful misconduct of Wyeth or any Wyeth Indemnified Party.

         10.2     INDEMNIFICATION BY WYETH. Wyeth will indemnify, defend and
                  hold harmless Neurocrine and its sublicensees, distributors
                  and each of its and their respective employees, officers,
                  directors and agents (each, a "Neurocrine Indemnified Party")
                  from and against any and all Liabilities that the Neurocrine
                  Indemnified Party may be required to pay to one or more Third
                  Parties resulting from or arising out of any Third Party
                  claims of any nature arising out of:

                  (a)      the conduct of any activities by, on behalf of, or
                           under the authority of Wyeth (other than by DOV,
                           Neurocrine, Pfizer or their respective Affiliates)
                           prior to the Effective Date of this Agreement; and/or

                  (b)      any Wyeth representation or warranty set forth herein
                           being untrue in any material respect when made;

                  except in each case, to the extent caused by the negligence or
                  willful misconduct of DOV, Neurocrine or any Neurocrine
                  Indemnified Party.

         10.3     PROCEDURE. Each Party will notify the other in the event it
                  becomes aware of a claim for which indemnification may be
                  sought hereunder. In case any proceeding (including any
                  governmental investigation) shall be instituted involving any
                  Party in respect of which indemnity may be sought pursuant to
                  this Article 10, such Party (the "Indemnified Party") shall
                  promptly notify the other Party (the "Indemnifying Party") in
                  writing within fifteen (15) days and the Indemnifying Party
                  and Indemnified Party shall meet to discuss how to respond to
                  any claims that are the subject matter of such proceeding. The
                  Indemnifying Party, upon request of the Indemnified Party,
                  shall retain counsel reasonably satisfactory to the
                  Indemnified Party to represent the Indemnified Party and shall
                  pay the fees and expenses of such counsel related to such
                  proceeding. The Indemnified Party agrees to cooperate fully
                  with the Indemnifying Party in the defense of any such claim,
                  action or proceeding, or any litigation resulting from any
                  such claim. In any such proceeding, the Indemnified Party
                  shall have the right to retain its own counsel, but the fees
                  and expenses of such counsel shall be at the expense of the
                  Indemnified Party unless (a) the Indemnifying Party and the
                  Indemnified Party shall have mutually agreed to the retention
                  of such counsel or (b) the named parties

                                  Page 19 of 24


                  to any such proceeding (including any impleaded parties)
                  include both the Indemnifying Party and the Indemnified Party
                  and representation of both Parties by the same counsel would
                  be inappropriate due to actual or potential differing
                  interests between them. All such fees and expenses shall be
                  reimbursed as they are incurred. The Indemnifying Party shall
                  not be liable for any settlement of any proceeding effected
                  without its written consent, but if settled with such consent
                  or if there be a final judgment for the plaintiff, the
                  Indemnifying Party agrees to indemnify the Indemnified Party
                  from and against any loss or liability by reason of such
                  settlement or judgment. The Indemnifying Party shall not,
                  without the written consent of the Indemnified Party, effect
                  any settlement of any pending or threatened proceeding in
                  respect of which the Indemnified Party is, or arising out of
                  the same set of facts could have been, a party and indemnity
                  could have been sought hereunder by the Indemnified Party,
                  unless such settlement includes an unconditional release of
                  the Indemnified Party from all liability on claims that are
                  the subject matter of such proceeding.

         10.4     INSURANCE. Neurocrine further agrees to use reasonable efforts
                  to obtain and maintain, during the term of this Agreement,
                  commercial general liability insurance, including products
                  liability insurance, with reputable and financially secure
                  insurance carriers to cover its indemnification obligations
                  under Sections 10.1 with limits of not less than Five Million
                  Dollars ($5,000,000.00) per occurrence and in the aggregate.
                  Insurance shall be procured with carriers having an A.M. Best
                  Rating of A-VII or better. Upon Wyeth's request, Neurocrine
                  shall provide Wyeth with a certificate of insurance evidencing
                  said coverage.

         10.5     LIMITATION. IN NO EVENT SHALL EITHER PARTY BE LIABLE TO THE
                  OTHER PARTY UNDER THIS AGREEMENT FOR SPECIAL, INDIRECT,
                  INCIDENTAL OR CONSEQUENTIAL DAMAGES SUFFERED BY SUCH OTHER
                  PARTY EXCEPT (A) TO THE EXTENT SUCH DAMAGES ARE PAID TO A
                  THIRD PARTY AS PART OF OR OTHERWISE INCURRED IN CONNECTION
                  WITH A THIRD PARTY CLAIM AND (B) IN THE EVENT OF INTENTIONAL
                  AND WILLFUL BREACH IN BAD FAITH OF ANY REPRESENTATION,
                  WARRANTY OR COVENANT MADE BY SUCH PARTY HEREUNDER.

11.      MISCELLANEOUS.

         11.1     ASSIGNMENT. Neither this Agreement nor any interest hereunder
                  shall be assignable by either Party, without the prior written
                  consent of the other Party, which consent shall not be
                  unreasonably withheld or delayed, except a Party may make such
                  an assignment without the other Party's consent to Affiliates
                  or to a successor to substantially all of the business of such
                  Party to which this Agreement relates, whether in merger, sale
                  of stock, sale of assets or other transaction. This Agreement
                  shall be binding

                                  Page 20 of 24


                  upon the successors and permitted assigns of the Parties and
                  the name of a Party appearing herein shall be deemed to
                  include the names of such Party's successors and permitted
                  assigns to the extent necessary to carry out the intent of
                  this Agreement. Any assignment not in accordance with this
                  Section 11.1 shall be void.

         11.2     FURTHER ACTIONS. Each Party agrees to execute, acknowledge and
                  deliver such further instruments, and to do all such other
                  acts, as may be necessary or appropriate in order to carry out
                  the purposes and intent of this Agreement.

         11.3     NOTICES. All notices and other communications hereunder
                  (including, without limitation, any notice of breach,
                  termination, change of address, etc.) shall be in writing and
                  shall be deemed given if delivered personally or by facsimile
                  transmission (receipt verified), mailed by registered or
                  certified mail (return receipt requested), postage prepaid, or
                  sent by nationally recognized express courier service, to the
                  Parties at the following addresses (or at such other address
                  for a Party as shall be specified by like notice, provided,
                  however, that notices of a change of address shall be
                  effective only upon receipt thereof):

                  All correspondence to Wyeth shall be addressed as follows:

                           Wyeth Pharmaceuticals
                           500 Arcola Road
                           Collegeville, PA  19426
                           Attn: Senior Vice President, Worldwide Licensing
                           Fax:  (484) 865-9301

                                 with a copy to:

                                 Wyeth
                                 5 Giralda Farms
                                 Madison, NJ  07940
                                 Attn: General Counsel
                                 Fax:  (973) 660-7156

                  All correspondence to Neurocrine shall be addressed as
follows:

                           Neurocrine Biosciences, Inc.
                           10555 Science Center Drive
                           San Diego, California  92121
                           Attn: Senior Vice President, Business Development
                           Fax:  (858) 658-7605

                                 with a copy to:

                                  Page 21 of 24


                                 Neurocrine Biosciences, Inc.
                                 10555 Science Center Drive
                                 San Diego, California  92121
                                 Attn: General Counsel
                                 Fax:  (858) 658-7605

         11.4     AMENDMENT. No amendment, modification or supplement of any
                  provision of this Agreement shall be valid or effective unless
                  made in writing and signed by a duly authorized officer of
                  each Party.

         11.5     WAIVER. No provision of the Agreement shall be waived by any
                  act, omission or knowledge of a Party or its agents or
                  employees except by an instrument in writing expressly waiving
                  such provision and signed by a duly authorized officer of the
                  waiving Party. The waiver by either of the Parties of any
                  breach of any provision hereof by the other Party shall not be
                  construed to be a waiver of any succeeding breach of such
                  provision or a waiver of the provision itself.

         11.6     SEVERABILITY. If any clause or portion thereof in this
                  Agreement is for any reason held to be invalid, illegal or
                  unenforceable, the same shall not affect any other portion of
                  this Agreement, as it is the intent of the Parties that this
                  Agreement shall be construed in such fashion as to maintain
                  its existence, validity and enforceability to the greatest
                  extent possible. In any such event, this Agreement shall be
                  construed as if such clause of portion thereof had never been
                  contained in this Agreement, and there shall be deemed
                  substituted therefor such provision as will most nearly carry
                  out the intent of the Parties as expressed in this Agreement
                  to the fullest extent permitted by applicable law.

         11.7     DESCRIPTIVE HEADINGS. The descriptive headings of this
                  Agreement are for convenience only, and shall be of no force
                  or effect in construing or interpreting any of the provisions
                  of this Agreement.

         11.8     GOVERNING LAW; DISPUTE RESOLUTION. This Agreement shall be
                  governed by and interpreted in accordance with the substantive
                  laws of the State of New York, without regard to conflict of
                  law principles thereof. The Parties recognize that a bona fide
                  dispute as to certain matters may from time to time arise
                  during the term of this Agreement. In the event of the
                  occurrence of such a dispute either Party may, by written
                  notice to the other Party, have such dispute referred to their
                  respective officers (designated below) or their successors or
                  designees for attempted resolution by good faith negotiations
                  within ten (10) calendar days after such notice is received.
                  Said designated officers are as follows:

                           For Wyeth:                Senior Vice President

                                  Page 22 of 24


                                                     Global Business Development
                                                     Wyeth Pharmaceuticals

                           For Neurocrine:           Senior Vice President,
                                                     Business Development

                  In the event the designated officers are not able to resolve
                  such dispute through good faith negotiations within such ten
                  (10) calendar day period, either Party may pursue any legal or
                  equitable remedies available to it by filing a claim in the
                  state or federal courts of the state of New York and each
                  Party hereby consents to the jurisdiction of such court and
                  each Party hereby irrevocably waives its right to a jury trial
                  before such court. Notwithstanding the foregoing, nothing in
                  this Section 11.8 shall prohibit a Party from seeking
                  temporary or injunctive relief from a state or federal court
                  in New York pending the resolution of a dispute in accordance
                  with the provisions of this Section 11.8.

         11.9     ENTIRE AGREEMENT OF THE PARTIES. This Agreement constitutes
                  and contains the complete, final and exclusive understanding
                  and agreement of the Parties as to the subject matter hereof
                  and cancels and supersedes any and all prior negotiations,
                  correspondence, understandings and agreements, whether oral or
                  written, among the Parties respecting the subject matter
                  hereof,. Except as expressly provided otherwise herein, this
                  Agreement shall have no effect on, and shall be subject to,
                  the 2002 Consent Agreement, the 2004 Consent Agreement, the
                  Sublicense Agreement and Compound License Agreement which
                  agreements shall continue in full force and effect in
                  accordance with the terms and conditions thereof and subject
                  to the assignments and assumptions effected pursuant to this
                  Agreement.

         11.10    INDEPENDENT CONTRACTORS. Both Parties are independent
                  contractors under this Agreement. Nothing herein contained
                  shall be deemed to create an employment, agency, joint venture
                  or partnership relationship between the Parties hereto or any
                  of their agents or employees, or any other legal arrangement
                  that would impose liability upon one Party for the act or
                  failure to act of the other Party. Neither Party shall have
                  any express or implied power to enter into any contracts or
                  commitments or to incur any liabilities in the name of, or on
                  behalf of, the other Party, or to bind the other Party in any
                  respect whatsoever.

                                  Page 23 of 24


         11.11    COUNTERPARTS. This Agreement may be executed in any number of
                  counterparts, each of which need not contain the signature of
                  more than one Party but all such counterparts taken together
                  shall constitute one and the same agreement.

         IN WITNESS WHEREOF, duly authorized representatives of the Parties have
duly executed this Agreement to be effective as of the Signature Date.

WYETH HOLDINGS CORPORATION                       NEUROCRINE BIOSCIENCES, INC.

By /s/ Robert A. Dougan                          By /s/ Gary A. Lyons
Name: Robert A. Dougan                           Name: Gary A. Lyons
Title: Senior Vice President                     Title: President and CEO

                                  Page 24 of 24


                                  EXHIBIT 1.23

                                  WYETH PATENTS

CL 285,489

United States

U.S. 6,399,621          expires 8/9/2020

U.S. 4,900,836          expires 2/13/2007

U.S. 4,521,422          expires 6/23/2003