<PAGE>

                                                                   Exhibit 10.65

  Confidential Materials omitted and filed separately with the Securities and
                Exchange Commission. Asterisks denote omissions.

                           EXCLUSIVE LICENSE AGREEMENT

      Effective as of November 2, 1998 ("Effective Date"), THE BOARD OF TRUSTEES
      OF THE LELAND STANFORD JUNIOR UNIVERSITY, a body having corporate powers
      under the laws of the State of California ("STANFORD"), JOHNS HOPKINS
      UNIVERSITY, a Maryland Corporation ("JHU") and Ontogeny, Inc., having a
      principal place of business at 45 Moulton Street, Cambridge, MA 02138
      ("LICENSEE"), agree as follows:

1.    BACKGROUND

1.1   STANFORD has an assignment of [**] from the laboratory of Dr. Roel Nusse,
      a Howard Hughes Medical Institute ("HHMI") investigator at STANFORD, as
      described in Stanford Docket S96-030 and Johns Hopkins University has an
      assignment of [**] from the laboratory of Dr. Jeremy Nathans, an HHMI
      investigator at JHU, as described in DM-3250, collectively referred to as
      "Invention", and any Licensed Patent, as hereinafter defined, which may
      issue to such Invention.

1.2   STANFORD and JHU desire to have the Invention perfected and marketed at
      the earliest possible time in order that products resulting therefrom may
      be available for public use and benefit.

1.3   LICENSEE desires a license under Invention and Licensed Patent to develop,
      manufacture, use, and sell Licensed Product in the field of use of human
      and veterinary therapeutics, drug discovery and diagnostics.

1.4   The Invention was made in the course of research supported by the Howard
      Hughes Medical Institute.

2.    DEFINITIONS

2.1   "Exclusive" means that, subject to Article 3, STANFORD or JHU shall not
      grant further licenses in the Licensed Territory in the Licensed Field of
      Use.

2.2   "Licensed Field of Use" means human and veterinary therapeutics, drug
      discovery and diagnostics.

2.3   "Licensed Materials" means proprietary materials of JHU or Stanford which
      are developed by JH or Stanford as a result of research concerning the
      Licensed Invention and identified in Appendix A hereto. Such Appendix to
      be periodically updated by reasonable mutual agreement and supplied to
      Licensee by Stanford and JHU.

2.4   "Licensed Patent" means U.S. Patent Application, Serial Number 832,340,
      filed April 11, 1997, and any divisions, continuations, and continuation
      in part patent applications (CIPs) which CIPs are directed to subject
      matter specifically described in the above patent application, and any
      foreign patent application or equivalent corresponding thereto
<PAGE>

      and any Letters patent or equivalent thereof issuing thereon or reissue,
      reexamination or extension thereof.

2.5   "Licensed Product" means any product or part thereof in the Licensed Field
      of Use, the manufacture, use, or sale of which:

      (a)   Is covered by a valid claim of an issued, unexpired Licensed Patent
            directed to the Invention in the country in which it is made, used
            or sold. A claim of an issued, unexpired Licensed Patent shall be
            presumed to be valid unless and until it has been held to be invalid
            by a final judgment of a court of competent jurisdiction from which
            no appeal can be or is taken; or

      (b)   Is covered by any claim being prosecuted in a pending application of
            Licensed Patent(s) in the country in which it is made, used or sold
            unless such claim has been pending in such application or an earlier
            application of Licensed Patent(s) for greater than 5 years; or

      (c)   Incorporates any of the Licensed Materials.

2.6   "Licensed Territory" means worldwide.

2.7   "Net Sales" means the gross revenue derived by LICENSEE from Licensed
      Product, less the following items but only insofar as they actually
      pertain to the disposition of such Licensed Product by LICENSEE, are
      included in such gross revenue, and are separately billed:

      (a)   Import, export, excise and sales taxes, and custom duties;

      (b)   Costs of installation at the place of use;

      (c)   Credit for returns, allowances, or trades.

      (d)   Costs of insurance, packing and transportation from the place of
            manufacture to the customer's premises or point of installation; and

      (e)   Customary trade, quantity or cash discounts actually allowed or
            taken. Where Licensed Products are not sold separately, but are sold
            in combination with or as parts of other products, hereinafter such
            combinations referred to as "a Combination Product" and the Licensed
            Product and each such other product being referred to as a Component
            Product", the Net Sales price to be used for the purpose of
            calculating royalties payable in respect of Combination Products
            must be determined by multiplying the Net Sales price of the
            Combination Product by the percentage value of the Licensed Product
            comprising a Component Product contained in the Combination Product,
            such percentage value being determined by dividing the current
            market value of the Licensed Product comprising a Component Product
            by a sum of the separate current market values of each of the
            Component Products which are contained in the Combination Product.
            The current market value of each of the Component Products must be
            for a quantity


                                     - 2 -
<PAGE>

  Confidential Materials omitted and filed separately with the Securities and
                Exchange Commission. Asterisks denote omissions.

            comparable to that contained in the Combination Product and of the
            same class, purity and potency. When no current market value is
            available for a Component Product, a reasonable hypothetical market
            value for such Component Product based upon the allocation of the
            same proportions of costs, reasonable overhead and profits (all of
            which must be determined on the basis of generally accepted
            accounting principles) as are or should be allocated to similar
            Component Products and having an ascertainable market value.

3.    GRANT

3.1   (a)   STANFORD and JHU hereby grants and LICENSEE hereby accepts a license
            in the Licensed Field of Use to make, use, and sell Licensed Product
            in the Licensed Territory and to use Invention and Licensed
            Materials.

      (b)   LICENSEE acknowledges that STANFORD and JHU have granted to HHMI a
            royalty-free, non-exclusive, non-transferable license with respect
            to the Invention, the Licensed Materials, and the Licensed Patents
            solely for HHMI's research and other noncommercial purposes.

3.2   Said license set forth in Section 3.1(a) above is Exclusive, including the
      right to sublicense pursuant to Article 12, in the Licensed Field of Use
      for a term commencing as of the Effective Date and ending, on a
      country-by-country basis, [**] from the date of first commercial sale of a
      Licensed Product by LICENSEE or sublicensee(s) in such country. LICENSEE
      agrees to promptly inform STANFORD in writing of the date of first
      commercial sale. If three months prior to the expiration of the exclusive
      term, LICENSEE can demonstrate to STANFORD that it has and will continue
      to effectively exploit the Inventions, Licensed Patents and Licensed
      Materials under this Agreement, then the term of the exclusive rights
      granted may be extended, such extension not to be unreasonably withheld by
      STANFORD. Upon expiration of the exclusive term of the license, said
      license shall be nonexclusive until expiration of the last to expire of
      Licensed Patents.

3.3   STANFORD and JHU shall have the right to practice the Invention and use
      the Licensed Materials for their own research and other noncommercial
      purposes or in non-commercial research collaborations with third party
      academic or not-for-profit research institutions, including STANFORD's and
      JHU's right to make Licensed Materials available to colleagues at academic
      and not-for-profit institutions. Any Licensed Materials that are
      transferred to a third party academic or not-for-profit institution by
      STANFORD or JHU shall be sent by Ontogeny tinder an MTA. STANFORD and JHU
      shall have the right to publish any information included in Licensed
      Patents.

4.    DILIGENCE

4.1   As an inducement to STANFORD and to JHU to enter into this Agreement,
      LICENSEE agrees to use reasonable efforts and diligence to proceed with
      the development, manufacture, and sale or lease of Licensed Product and to
      diligently develop markets for


                                     - 3 -
<PAGE>

  Confidential Materials omitted and filed separately with the Securities and
                Exchange Commission. Asterisks denote omissions.

      the Licensed Product. Unless LICENSEE has a Licensed Product available for
      commercial sale prior to [**], LICENSEE agrees that STANFORD may terminate
      this Agreement. Anytime after [**] years from the date of license,
      STANFORD may terminate this Agreement if ONTOGENY or a sublicensee has not
      sold a Licensed Product for a period of 1 year and is not demonstrably
      engaged in a research, development, manufacturing, marketing or licensing
      program, as appropriate, directed toward the development and
      commercialization of the licensed subject matter.

4.2   Progress Report - On or before September 1 of each year until LICENSEE
      markets a Licensed Product, STANFORD may request in writing that LICENSEE
      shall submit a written annual report to STANFORD covering the preceding
      year ending June 30, regarding the progress of LICENSEE toward commercial
      use of Licensed Product. Such report shall include, as a minimum,
      information sufficient to enable STANFORD and JHU to satisfy reporting
      requirements of HHMI and for STANFORD to ascertain progress by LICENSEE
      toward meeting the diligence requirements of this Article 4.

5.    ROYALTIES

5.1   In connection with a Letter of Intent signed by the parties on August 28,
      1998, LICENSEE has paid to STANFORD a noncreditable, nonrefundable license
      issue royalty of [**], which money was to be held in escrow until the
      execution of this Agreement.

5.2   Beginning October 1, 1999 and each October 1 thereafter, LICENSEE also
      shall pay to STANFORD the following yearly royalty:

            Anniversaries 1-5             [**]

            Anniversary 6 and thereafter  [**].

      If this agreement becomes non-exclusive, the yearly royalty shall be
      reduced to an amount equal to 1/n times the yearly royalty in this Section
      5.2 owed during the exclusive period of the Agreement where n equals that
      number of licensees of the Licensed Patent.

      Said yearly royalty payments are nonrefundable, but they are creditable
      against earned royalties to the extent provided in Paragraph 5.5.

5.3   In addition, LICENSEE shall pay STANFORD earned royalties on Net Sales as
      follows:

            Royalties on Net Sales by Ontogeny:

      (a)   If gene product claimed in Licensed Patent is the drug and Licensed
            Patent is the sole patent/patent application covering sale of such
            Licensed Product: [**]

      (b)   If Licensed Patent is the key, but not sole, patent/patent
            application having claim(s) covering sale of Licensed Product: [**]

      (c)   If patent claim of Licensed Patent covers sale of Licensed Product,
            but is not key patent/patent application covering sale of Licensed
            Product: [**]


                                     - 4 -
<PAGE>

  Confidential Materials omitted and filed separately with the Securities and
                Exchange Commission. Asterisks denote omissions.

      (d)   If product commercialized by LICENSEE is not covered by a claim of
            Licensed Patents, but such product is identified or discovered in
            material part through the use of a Licensed Product:

            on Net Sales in the United States up to [**]               [**]
            on Net Sales in the United States over [**]                [**]

      If this agreement becomes non-exclusive, the royalty shall be reduced to
      an amount equal to 1/n times the earned royalty in this Section 5.3 owed
      during the exclusive period of the Agreement where n equals the number of
      licensees of the Licensed Patent.

5.4   LICENSEE also agrees to make the following milestone payments for the
      first Licensed Product to attain such a milestone:

            Upon IND filing                                 [**]
            Initiation of Phase III clinical trials         [**]
            Upon NDA filing                                 [**]

      Said milestone payments are nonrefundable, but they are creditable against
      earned royalties in the manner set forth in Section 5.5.

5.5   Creditable payments under Sections 5.2 and 5.4 of this Agreement shall be
      an offset to LICENSEE against up to fifty percent (50%) of each earned
      royalty payment which LICENSEE would be required to pay pursuant to
      Paragraph 5.3 until the entire credit is exhausted.

5.6   If this Agreement is not terminated in accordance with other provisions
      hereof, LICENSEE's obligation to pay royalties hereunder shall continue
      for so long as LICENSEE, by its activities would, but for the license
      granted herein, infringe a valid claim of an unexpired Licensed Patent of
      STANFORD covering said activity or, with regard to a product set forth in
      Paragraph 5.3(d) which is not covered by a claim of Licensed Patent, until
      6 years after first commercial sale of a product set forth in Paragraph
      5.3 (d).

5.7   The royalty on sales in currencies other than U.S. Dollars shall be
      calculated using the appropriate foreign exchange rate for such currency
      quoted by the Bank of America (San Francisco) foreign exchange desk, on
      the close of business on the last banking day of each calendar quarter.
      Royalty payments to STANFORD shall be in U.S. Dollars. All non-U.S. taxes
      related to royalty payments shall be paid by LICENSEE and are not
      deductible from the payments due STANFORD. In the event that LICENSEE is
      required to withhold taxes imposed upon STANFORD for any payment under
      this Agreement by virtue of the statutes, laws, codes or governmental
      regulations of a foreign country in which Licensed Products are sold, then
      such payments will be made by LICENSEE without deduction from the payment
      due STANFORD. STANFORD shall assist LICENSEE as reasonably requested by
      LICENSEE and at LICENSEE's expense, in recovering such taxes to the extent
      possible tinder applicable tax laws and treaties.


                                     - 5 -
<PAGE>

5.8   Within forty-five (45) days after receipt of a statement from STANFORD,
      LICENSEE shall reimburse STANFORD for all costs incurred by STANFORD,
      prior to the Effective Date which shall not exceed $12,000, in connection
      with the preparation, filing, and prosecution of all patent applications
      and maintenance of patents corresponding to the Invention. After the
      Effective Date, and during the exclusive term of the license, LICENSEE
      will be responsible for the filing, prosecution and maintenance of the
      Licensed Patent (s) and the costs incurred by LICENSEE related to such
      filing, prosecution and maintenance. Licensee may use patent counsel of
      its own choosing, reasonably acceptable to STANFORD and JHU, provided that
      STANFORD and JHU shall be kept informed of and shall receive copies of all
      documentation and substantive actions pertaining to the filing,
      prosecution and maintenance of Licensed Patent(s). STANFORD and JHU shall
      have reasonable opportunities to participate in decision making and
      LICENSEE will use diligent efforts to incorporate STANFORD's and JHU's
      reasonable suggestions. If LICENSEE elects not to continue to seek or
      maintain patent protection on any Licensed Patent in any country during
      the exclusive term of the license, STANFORD and JHU shall have the right,
      at its expense, to procure, maintain and enforce in any country such
      Licensed Patent(s) and LICENSEE shall have no further rights under the
      Licensed Patent(s) in such country.

5.9   Only one royalty is due on each Licensed Product sold by LICENSEE
      regardless of whether its manufacture, use or sale are or shall be covered
      by more than one patent or patent application included in Licensed Patent
      (s) licensed under this Agreement, and no further royalties will be due
      for use of such Licensed Product by LICENSEES customers.

5.10  STANFORD and JHU shall work out a mutually agreeable arrangement for the
      sharing of revenue underneath this Exclusive License Agreement.

6.    ROYALTY REPORTS, PAYMENTS, AND ACCOUNTING

6.1   Quarterly Earned Royalty Payment and Report - Beginning with the first
      sale of a Licensed Product, LICENSEE shall make written reports (even if
      there are no sales) and earned royalty payments to STANFORD within
      forty-five (45) days after the end of each calendar quarter. This report
      shall state the number, description, and aggregate Net Sales of Licensed
      Product during such completed calendar quarter, and resulting calculation
      pursuant to Paragraph 5.3 of earned royalty payment due STANFORD for such
      completed calendar quarter. Concurrent with the making of each such
      report, LICENSEE shall include payment due STANFORD of royalties for the
      calendar quarter covered by such report.

6.2   Accounting - LICENSEE agrees to keep and maintain records for a period of
      three (3) years showing the manufacture, sale, use, and other disposition
      of products sold or otherwise disposed of under the license herein
      granted. Such records will include general ledger records showing cash
      receipts and expenses, and records which include production records,
      customers, serial numbers, and related information in sufficient detail to
      enable the royalties payable hereunder by LICENSEE to be determined.
      LICENSEE further agrees to permit its books and records to be examined by
      an independent certified public accountant selected by STANFORD and
      acceptable to LICENSEE from time to time to


                                     - 6 -
<PAGE>

      the extent necessary to verify reports provided for in Paragraph 6.1. Such
      examination is to be made at the expense of STANFORD, except in the event
      that the results of the audit reveal an underreporting of royalties due
      STANFORD of five percent (5%) or more, then the audit costs shall be paid
      by LICENSEE.

7.    WARRANTIES

7.1   To the best of STANFORD's OTL and JHU's OTL knowledge, STANFORD and JHU
      are sole owners of U.S. Patent Application, Serial No. 832,340, filed
      April 11, 1997.

7.2   Nothing in this Agreement is or shall be construed as:

      (a)   A warranty or representation by STANFORD or JHU as to the validity
            or scope of any Licensed Patent;

      (b)   A warranty or representation that anything made, used, sold, or
            otherwise disposed of under any license granted in this Agreement is
            or will be free from infringement of patents, copyrights, and other
            rights of third parties; however, STANFORD does represent that
            neither it nor JHU has received notice of any assertion that any of
            the patents or subject inventions infringe upon any third party's
            know-how, patent or other intellectual property rights as of the
            Effective Date.

      (c)   An obligation to bring or prosecute actions or suits against third
            parties for infringement, except to the extent and in the
            circumstances described in Article 11;

      (d)   Granting by implication, estoppel, or otherwise any licenses or
            rights under patents or other rights of STANFORD or JHU or other
            persons other than Licensed Patent, regardless of whether such
            patents or other rights are dominant or subordinate to any Licensed
            Patent; or

      (e)   A warranty or representation by STANFORD or JHU that any Letters
            Patent will issue with respect to Licensed Patent.

7.3   Except as expressly set forth in this Agreement, STANFORD or JHU MAKE NO
      REPRESENTATIONS AND EXTENDS NO WARRANTIES OF ANY KIND, EITHER EXPRESS OR
      IMPLIED. THERE ARE NO EXPRESS OR IMPLIED WARRANTIES OF MERCHANTABILITY OR
      FITNESS FOR A PARTICULAR PURPOSE, OR THAT THE USE OF THE INVENTION, THE
      LICENSED PATENT, OR THE LICENSED PRODUCT WILL NOT INFRINGE ANY PATENT,
      COPYRIGHT, TRADEMARK, OR OTHER RIGHTS OR ANY OTHER EXPRESS OR IMPLIED
      WARRANTIES.

7.4   LICENSEE agrees that nothing in this Agreement grants LICENSEE any express
      or implied license or right under or to U.S. Patent 4,656,134
      'Amplification of Eucaryotic Genes' or any patent application
      corresponding thereto.


                                     - 7 -
<PAGE>

8.    INDEMNITY

8.1   LICENSEE agrees on behalf of itself and each Affiliate to indemnify, hold
      harmless, and defend STANFORD, JHU, and Stanford Health Services, JHU,
      HHMI and UCSF Stanford Health Care and their respective trustees,
      officers, employees, students, and agents against any and all claims,
      actions, demands, suits or causes of action for damages, whether arising
      from death, illness, personal injury, property damage, and improper
      business practices, or otherwise, arising out of (a) any breach or alleged
      breach of this Agreement by LICENSEE and to the extent that the LICENSEE
      may be responsible for payment to a third party under this indemnity, or
      any of its Affiliates or any company that has a controlling interest in
      LICENSEE, or (b) any manufacture, use, sale, or other disposition of
      Invention, Licensed Patent, Licensed Material, or Licensed Product, by
      LICENSEE or its affiliates except if such claims are due to the gross
      negligence or willful acts of STANFORD and JHU. STANFORD agrees to
      promptly notify LICENSEE in writing of any such claim, other than any
      claim for breach of this Agreement by LICENSEE, LICENSEE shall manage and
      control, at its own expense, the defense of such claim and its settlement,
      utilizing attorney's reasonably acceptable to STANFORD, JHU and HHMI.
      LICENSEE agrees not to settle any such claim against any Indemnitee
      without STANFORD's, JHU's and HHMI's written consent where such settlement
      would include any admission of liability on the part of any Indemnitee,
      where the settlement would impose any restriction on the conduct by the
      Indemnitee of any of its activities, or where the settlement would not
      include an unconditional release of such Indemnitee from all liability for
      claims that are the subject matter of such claim. STANFORD, HHMI and JHU
      shall not settle any claim covered by the indemnity without the prior
      written consent of LICENSEE which consent shall not be unreasonably
      withheld or delayed. This section 8.1 will survive termination of this
      Agreement.

8.2   Without limiting Section 8.1, STANFORD shall not be liable for any
      indirect, special, or consequential damages whatsoever unless due to the
      gross negligence or willful misconduct of STANFORD or JHU. STANFORD and
      JHU shall have no responsibilities or liabilities whatsoever with respect
      to Licensed Products.

8.3   LICENSEE shall at all times comply, through insurance or self-insurance,
      with all statutory workers' compensation and employers' liability
      requirements covering any and all employees with respect to activities
      performed under this Agreement.

8.4   In addition to the foregoing, LICENSEE shall maintain, during the term of
      this Agreement, Comprehensive General Liability Insurance, including
      Products Liability Insurance, with reputable and financially secure
      insurance carrier(s) to cover the activities of LICENSEE and its
      sublicensee(s). Upon initiation of clinical trials of the Licensed
      Product, such insurance shall provide minimum limits of liability of
      $5,000,000 and shall expressly include STANFORD, Stanford Health Services,
      HHMI, JHU, their respective trustees, directors, officers, employees,
      students, and agents as additional insureds. Such insurance shall be
      written to cover claims incurred, discovered, manifested, or made during
      or after the expiration of this Agreement up to a limit of 7 years after
      the product


                                     - 8 -
<PAGE>

      is no longer sold and should be placed with carriers with ratings of at
      least A- as rated by A.M. Best. At STANFORD's request, LICENSEE shall
      furnish a Certificate of Insurance evidencing primary coverage and
      requiring thirty (30) days prior written notice of cancellation or
      material change to STANFORD. LICENSEE shall advise STANFORD, in writing,
      that it maintains excess liability coverage (following form) over primary
      insurance for at least the minimum limits set forth above. All such
      insurance of LICENSEE shall be primary coverage; insurance of STANFORD,
      HHMI, JHU or Stanford Health Services shall be excess and noncontributory.

9.    MARKING

      Prior to the issuance of patents on the Invention, LICENSEE agrees to mark
      Licensed Products (or their containers or labels) made, sold, or otherwise
      disposed of by it under the license granted in this Agreement with the
      words "Patent Pending," and following the issuance of one or more patents,
      with the numbers of the Licensed Patent.

10.   STANFORD NAMES AND MARKS

      LICENSEE agrees not to identify STANFORD, JHU or HHMI in any promotional
      advertising or other promotional materials to be disseminated to the
      public or any portion thereof or to use the name of any STANFORD, JHU or
      HHMI faculty member, employee, or student or any trademark, service mark,
      trade name, or symbol of STANFORD, JHU or HHMI or the Stanford Health
      Services, or that is associated with any or either of them, without
      STANFORD's, JHU's or HHMI's prior written consent.

11.   INFRINGEMENT BY OTHERS: PROTECTION OF PATENTS

11.1  LICENSEE, STANFORD and JHU shall promptly inform the other party of any
      suspected infringement of any Licensed Patent by a third party. During the
      exclusive period of this Agreement, STANFORD and LICENSEE each shall have
      the right to institute an action for infringement of the Licensed
      Patent(s) against such third party in accordance with the following:

      (a)   Within 30 days of notification, if STANFORD and LICENSEE agree to
            institute suit jointly, the suit shall be brought in both their
            names, the out-of-pocket costs thereof shall be borne equally, and
            any recovery or settlement shall be shared equally. LICENSEE and
            STANFORD shall agree to the manner in which they shall exercise
            control over such action. Each party may, if it so desires, also be
            represented by separate counsel of its own selection, the fees for
            which counsel shall be paid by such party.

      (b)   If STANFORD and LICENSEE do not institute suit jointly within 30
            days of notification as set forth in 11.1(a), LICENSEE shall be
            empowered to bring suit in its own name to enjoin such infringement.
            Licensee shall bear the entire cost of such litigation and shall be
            entitled to retain the entire amount of any recovery or


                                     - 9 -
<PAGE>

            settlement. However, any recovery in excess of litigation costs will
            be considered Net Sales, and LICENSEE will pay STANFORD royalties as
            indicated in Section 5.3. STANFORD shall provide reasonable
            assistance to LICENSEE in the prosecution of any such suit brought
            by LICENSEE.

      (c)   In the event that LICENSEE does not terminate such infringement or
            initiate steps to do so within six months of learning of such
            infringement, STANFORD may bring suit against infringer at its sole
            expense and shall be entitled to retain the entire amount of any
            recovery or settlement. LICENSEE will give reasonable assistance to
            STANFORD in the prosecution of any such suit brought by STANFORD.
            This Paragraph 11.1 shall survive termination of this Agreement.

11.2  Should either STANFORD or LICENSEE commence a suit under the provisions of
      Paragraph 11.1 and thereafter elect to abandon the same, it shall give
      timely notice to the other party who may, if it so desires, continue
      prosecution of such suit, provided, however, that the sharing of expenses
      and any recovery in such suit shall be as agreed upon between STANFORD and
      LICENSEE.

12.   SUBLICENSE(S)

12.1  LICENSEE may grant sublicense(s) to Licensed Patents and Licensed
      Materials during the term of this Agreement.

12.2  If LICENSEE is unable or unwilling to serve or develop a potential market
      or market territory for which there is a willing sublicensee(s), LICENSEE
      will, at STANFORD's request, negotiate in good faith a sublicense(s)
      hereunder. Bona fide business concerns of LICENSEE will be considered in
      any good faith negotiations for a sublicense under this Agreement.

12.3  Any sublicense(s) granted by LICENSEE under this Agreement shall be
      subject and subordinate to terms and conditions of this Agreement, except
      that the earned royalty rate specified in the sublicense(s) may be at
      higher rates than the rates in this Agreement and the sublicensee may
      further sublicense any rights under Licensed Patents or Licensed Materials
      only as: (a) needed or implied in the course of distribution, installation
      or performance of service as required for the sale to an end user of
      Licensed Products or Licensed Materials, or (b) not specifically rejected
      in writing by STANFORD within thirty (30) days of written notification of
      sub-sublicensee by LICENSEE, any such rejection not being unreasonably
      made by STANFORD. Without limiting the foregoing, any such sublicense(s)
      also shall expressly include the provisions of Articles 6, 7, 8, 10 and 15
      for the benefit of STANFORD, JHU and/or HHMI, as the case may be, and
      provide, at LICENSEE'S option, for the transfer of all obligations,
      including the payment of royalties specified in such sublicense(s), to
      STANFORD or its designee, in the event that this Agreement is terminated.

12.4  LICENSEE agrees to promptly provide STANFORD in confidence with a copy of
      the relevant portions of any sublicense granted pursuant to this Article
      12.


                                     - 10 -
<PAGE>

  Confidential Materials omitted and filed separately with the Securities and
                Exchange Commission. Asterisks denote omissions.

12.5  LICENSEE will pay to STANFORD [**] of all payments received from a
      sublicensee in consideration for the sublicensing of Licensed Patents as
      well as [**] of any royalties, fees or other amounts received by LICENSEE
      as a result of the sublicensee's sale of Licensed Products, excluding
      equity payments, milestone payments, amounts paid to fund research and
      development activities conducted by LICENSEE, and

12.6  reimbursement of patent costs. If LICENSEE is required to pay royalties to
      an additional party, STANFORD agrees in good faith to consider negotiating
      a reduction in royalties under this section.

13.   TERMINATION

13.1  LICENSEE may terminate this Agreement by giving STANFORD notice in writing
      at least thirty (30) days in advance of the effective date of termination
      selected by LICENSEE.

13.2  STANFORD and JHU may terminate this Agreement if LICENSEE:

      (a)   Is in default in payment of royalty or providing of reports;

      (b)   Is in breach of any provision hereof; or

      (c)   Provides any false report; and LICENSEE fails to remedy any such
            default, breach, or false report within thirty (30) days after
            written notice thereof by STANFORD.

13.3  Surviving any termination are:

      (a)   LICENSEE's obligation to pay royalties accrued or accruable;

      (b)   Any cause of action or claim of LICENSEE or STANFORD, accrued or to
            accrue, because of any breach or default by the other party; and

      (c)   The provisions of Articles 6, 7, and 8;

      (d)   The obligation to pay earned royalties under Paragraph 53(d) shall
            survive any termination until 6 years after first commercial sale of
            such product..

14.   ASSIGNMENT

      This Agreement may not be assigned except that LICENSEE may assign this
      Agreement to a party which acquires all or substantially all of that
      portion of LICENSEE's business to which this Agreement pertains, ,whether
      by merger, sale of assets or otherwise

15.   ARBITRATION

15.1  Apart from any controversy or claim pertaining to HHMI's rights under
      Article 8 or otherwise under this Agreement, any controversy arising under
      or related to this


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      Agreement, and any disputed claim by either 0 party against the other
      under this Agreement excluding any dispute relating to patent validity or
      infringement arising under this Agreement, shall be settled by arbitration
      in accordance with the Licensing Agreement Arbitration Rules of the
      American Arbitration Association.

15.2  Upon request by either party, arbitration will be by a third party
      arbitrator mutually agreed upon in writing by LICENSEE and STANFORD within
      thirty (30) days of such arbitration request. Judgment upon the award
      rendered by the arbitrator shall be final and nonappealable and may be
      entered in any court having jurisdiction thereof.

15.3  The parties shall be entitled to discovery in like manner as if the
      arbitration were a civil suit in the California Superior Court. The
      Arbitrator may limit the scope, time and/or issues involved in discovery.

16.   NOTICES

      All notices under this Agreement shall be deemed to have been fully given
      when done in writing and deposited in the United States mail, registered
      or certified, and addressed as follows:

To STANFORD:              Office of Technology Licensing
                          Stanford University
                          900 Welch Road, Suite 350
                          Palo Alto, CA 94304-1850
                          Attention: Director

To LICENSEE:              Ontogeny, Inc.
                          45 Moulton Street
                          Cambridge, MA 02138-1118
                          Attention: President and CEO

      Either party may change its address upon written notice to the other
      party.

17.   WAIVER

      None of the terms of this Agreement can be waived except by the written
      consent of the party waiving compliance.

18.   APPLICABLELAW

      This Agreement shall be governed by the laws of the State of California
      applicable to agreements negotiated, executed and performed wholly within
      California.

19.   CONFIDENTIALITY

      STANFORD and JHU agree that reasonable effort shall be used to maintain
      the confidentiality of reports or documents received from LICENSEE by
      STANFORD


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<PAGE>

      pursuant to this Agreement, provided that such reports or documents are
      marked as confidential.

      IN WITNESS WHEREOF, the parties hereto have executed this Agreement in
      duplicate originals by their duly authorized officers or representatives.


THE BOARD OF TRUSTEES OF THE LELAND STANFORD JUNIQR
UNIVERSITY


Signature:   /s/ Katharine Ku
          ----------------------------------------------
                 Name:  Katharine Ku
                 Title:  Director Oncology Licensing
                 Date:  November 5, 1998

JOHN HOPKINS UNIVERSITY


Signature:  /s/ Bart Chernow
          ----------------------------------------------
                 Name:  Bart Chernow, M.D.
                 Title:  Vice Dean for Research and Technology
                 Date:  November 16, 1998

ONTOGENY, ICN.


Signature:  /s/ Raul Rodriguez
          ----------------------------------------------
                 Name:  Raul Rodriguez
                 Title:  Vice President, Business Development
                 Date:  December 1, 1998


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                       APPENDIX A - LICENSED MATERIALS

                                    (NONE)