<PAGE>

                                                                   Exhibit 10.44

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

                                    Agreement

Effective as of September 26, 1996 ("Effective Date"), The Johns Hopkins
University, a body having corporate powers under the laws of the State of
Maryland ("JOHNS HOPKINS"), the University of Washington (the "UNIVERSITY OF
WASHINGTON"), a body having corporate powers under the laws of the State of
Washington, and Ontogeny Inc., a Delaware corporation having a principal place
of business at 45 Moulton Street, Cambridge, MA 02138 ("ONTOGENY"), agree as
follows:

                                   Article 1
                                   Background

1.1   JOHNS HOPKINS represents and warrants that it is Owner by assignment from
      Philip A. Beachy and Jeffrey Porter (both investigators employed by Howard
      Hughes Medical Institute ("HHMI")) and HHMI, and that the UNIVERSITY OF
      WASHINGTON represents and warrants that it is the Owner by assignment from
      Randall T. Moon (also an investigator employed by HHMI) and HHMI of the
      entire right, title and interest in the United States and Foreign Patent
      Applications ("Hedgehog Patent Applications") set forth in Appendix A, and
      in the inventions described and claimed therein ("Invention"), and any
      Licensed Patent, defined in Article 2, which may issue to the Invention,
      and that JOHNS HOPKINS and the UNIVERSITY OF WASHINGTON have the sole
      authority to grant the licenses granted hereunder.

1.2   JOHNS HOPKINS and the UNIVERSITY OF WASHINGTON have certain technical data
      and information ("Technology") pertaining to Invention.

1.3   JOHNS HOPKINS and the UNIVERSITY OF WASHINGTON want the Technology and
      Invention perfected and marketed in a reasonable period of time in order
      that resulting products will be available for public use and benefit.

1.4   ONTOGENY would like to practice the Invention and related Technology, and
      is therefore desirous of obtaining a license under Licensed Patent to
      develop, manufacture, use, and sell Licensed Product in the area of
      therapeutics, diagnostics and research reagents.


                                     - 1 -
<PAGE>

1.5   The Technology and Invention were developed in the course of research
      supported by the HHMI in affiliation with each of JOHNS HOPKINS and the
      UNIVERSITY OF WASHINGTON.

1.6   JOHNS HOPKINS and the UNIVERSITY OF WASHINGTON agree that all
      notifications and payments by ONTOGENY pursuant to this Agreement will be
      made to, and accepted by, JOHNS HOPKINS for the benefit of both JOHNS
      HOPKINS and the UNIVERSITY OF WASHINGTON.

                                    Article 2
                                   Definitions

2.1   "Licensed Patent(s)" means any U.S. Letters Patent issued upon the
      Hedgehog Patent Applications, or upon any divisions, continuations,
      reissues, reexamines, extensions, and any claims in continuations-in-part
      (CIPs) applications; and any and all foreign patents, extensions and
      supplemental protection certificates or patent applications corresponding
      thereto. All such divisions, continuations, reissues, reexaminations, CIPs
      and foreign applications and patents issuing thereon will be automatically
      incorporated in and added to this Agreement. CIP applications shall only
      be filed for new matter which supports claims to inventions described in
      the Hedgehog Patent Applications and could not be filed in a stand alone,
      original patent application.

2.2   "Licensed Materials" means those proprietary materials which are
      enumerated in Appendix B, and transferred from JOHNS HOPKINS through
      Philip A. Beachy to ONTOGENY pursuant to the terms of this Agreement.

2.3   "Licensed Product" means any product or process in the Licensed Field of
      Use, the importation, manufacture, use, offer for sale, or sale of which:

      (a)   is covered by a valid claim of an issued, unexpired Licensed Patent;
            a claim of an issued, unexpired Licensed Patent will be presumed to
            be valid unless it has been held to be invalid by a final judgment
            of a court of competent jurisdiction where no appeal can be or is
            taken; or


                                     - 2 -
<PAGE>

      (b)   is covered by any claim being prosecuted in a pending application in
            Licensed Patents, provided the claim has not been pending for more
            than 7 years; or

      (c)   clauses (a) and (b) notwithstanding, is covered by any pending or
            issued claim to bioactive Hedgehog polypeptides issuing from Harvard
            University Patents/Applications or Columbia University
            Patents/Applications (defined infra); or

      (d)   incorporates, uses or could not have been manufactured or discovered
            but for the use of Licensed Materials or materials covered by
            Licensed Patents (including expression products thereof and
            antibodies to such polypeptides).

2.4   "Net Sales" means the gross revenue derived by ONTOGENY or affiliate from
      sale(s) of Licensed Product to unrelated third parties, less the following
      items but only as they actually pertain to the disposition of the Licensed
      Product by ONTOGENY or affiliate, are included in the gross revenue, and
      are separately billed:

      (a)   Taxes levied on and/or other governmental charges made as to
            production, sales, transportation, delivery or use and paid by or on
            behalf of ONTOGENY;

      (b)   Costs of insurance, packing, and transportation, where separately
            invoiced and not paid by the customer, from the place of manufacture
            to the customer's premises or point of installation;

      (c)   Credit for returns, allowances, or trades; and

      (d)   Trade, quantity or cash discounts and non-affiliated brokers' or
            agents' commissions allowed and actually taken.

2.5   "Licensed Field of Use" means (i) human therapeutics for cancer, (ii)
      human therapeutics for neurobiology, (iii) human therapeutics for
      skeletal, (iv) human therapeutics for all other areas, (v) veterinary
      therapeutics, (vi) drug discovery, (vii) in vivo diagnostics, (viii) in
      vitro diagnostics, and (ix) research reagents.


                                     - 3 -
<PAGE>

2.6   "Exclusive" means that, subject to Article 3.3 and Article 4, neither
      JOHNS HOPKINS nor the UNIVERSITY OF WASHINGTON will grant additional
      licenses to Licensed Patents in the Licensed Field of Use.

2.7   "Sublicense" means any grant of rights under Licensed Patents, Harvard
      University Patents/Applications, Columbia University Patents/Applications,
      or Licensed Materials

2.8   "Sublicensee" means any party (excluding any corporation, partnership,
      joint venture or entity in which Ontogeny directly or indirectly owns or
      controls greater than fifty percent (50%) of the shares entitled to vote
      for election of directors) to which ONTOGENY has granted Sublicenses
      pursuant to this Agreement.

2.9   "Harvard University Patents/Applications" means U.S. Patent applications
      08/356,060 and 08/176,427, any divisions, continuations, reissues,
      reexamines, extensions, and CIPs thereof, and patents issuing therefrom
      and any and all foreign patents or patent applications or supplemental
      protection certificates corresponding thereto.

2.10  "Columbia University Patents/Applications" means U.S. Patent application
      08/202,040, any divisions, continuations, reissues, reexamines,
      extensions, and CIPs thereof, and patents issuing therefrom and any and
      all foreign patents or patent applications or supplemental protection
      certificates corresponding thereto.

                                    Article 3
                            License Grant to Ontogeny

3.1   JOHNS HOPKINS and the UNIVERSITY OF WASHINGTON grant to ONTOGENY, upon and
      subject to the terms and conditions in this Agreement,

            (i)   a worldwide Exclusive license to Licensed Patents, in the
                  Licensed Field of Use, to import, make, use, offer for sale,
                  sell, have made, and have sold Licensed Products described
                  and/or claimed therein; and

            (ii)  a worldwide non-exclusive license to Licensed Materials.


                                     - 4 -
<PAGE>

3.2   The period of the Exclusive license granted in Article 3.1, including the
      right to Sublicense pursuant to Article 14, in the Licensed Field of Use
      begins on the Effective Date and ends on the last to occur of:

      (a)   17 years from the Effective Date if no valid claims are issued in
            Licensed Patents or canceled pursuant to Article 7.5; or

      (b)   the expiration of the last patent under the Licensed Patents.

3.3   JOHNS HOPKINS, JOHNS HOPKINS HEALTH SYSTEMS, HHMI and the UNIVERSITY OF
      WASHINGTON have the right to practice the Invention for their own
      non-profit research purposes or in non-profit research collaborations with
      third party academic or not-for-profit research institutions. JOHNS
      HOPKINS, HHMI and the UNIVERSITY OF WASHINGTON also have the right to
      publish any information included in the Licensed Patent. In order that
      ONTOGENY may properly evaluate filing of CIP applications, JOHNS HOPKINS
      and the UNIVERSITY OF WASHINGTON agree to provide copies of manuscripts
      disclosing information that would be appropriate for filing a CIP
      application directly related to the Licensed Patents at least thirty (30)
      days in advance of any publication thereof (including any electronic
      publication), and copies of abstracts or oral disclosures disclosing
      information directly related to the Licensed Patents at least ten (10)
      days before public disclosure or publication. All manuscripts or abstracts
      provided to ONTOGENY shall only be shared on a confidential basis with
      employees of ONTOGENY except that ONTOGENY may share such information with
      its legal counsel prior to public disclosure or publication.

                                    Article 4
                   Rights of United States in Licensed Patents

This Agreement is subject to all of the terms and conditions of Title 35 United
States Code Sections 200 through 204. This includes the obligation that ONTOGENY
agrees that it shall manufacture and shall cause its Sublicensees (if any) to
manufacture, substantially in the United States all Licensed Product sold or
produced in the United States, and to take all reasonable action necessary to
enable JOHNS HOPKINS and the UNIVERSITY OF WASHINGTON to satisfy their
obligations to the United States Federal Government, relating to Licensed
Products.


                                     - 5 -
<PAGE>

                                    Article 5
                              Diligence by Ontogeny

5.1   As an inducement to JOHNS HOPKINS and the UNIVERSITY OF WASHINGTON to
      enter into this Agreement, ONTOGENY or its Sublicensees (if any) will use
      reasonable effort and diligence to proceed with the development,
      manufacture, and sale or lease of Licensed Product and to diligently
      develop markets for the Licensed Product. Specific milestones or other
      measures of diligence are set forth in Appendix C. If ONTOGENY or its
      Sublicensees (if any) fails to meet any such milestone as enumerated in
      Appendix C, JOHNS HOPKINS may institute proceedings to terminate
      Ontogeny's rights to certain areas in the Licensed Field of Use. Such
      termination proceedings will involve reasonable written notice to ONTOGENY
      specifically detailing the basis for JOHNS HOPKINS' termination, and a
      reasonable opportunity, including a further ninety (90) day cure period,
      for ONTOGENY to refute or cure the basis for JOHNS HOPKINS' concern.
      Should unexpected impediments occur during development, these milestones
      may be renegotiated by the parties upon written request by ONTOGENY
      detailing its diligent efforts, or those of its Sublicensees (if any), and
      reasons requesting modification of the milestones. In making their
      decision to terminate certain of ONTOGENY's rights, JOHNS HOPKINS shall
      take into consideration the normal course of such programs conducted with
      sound and reasonable business practices and judgment and shall take into
      account the reports provided under this Agreement by ONTOGENY.

5.2   In the event JOHNS HOPKINS becomes aware of third parties that wish to
      license the Licensed Patents in the Licensed Field of Use pursuant to
      Articles 2.5(viii) or 2.5(ix) and such license to a third party would not
      result in competition to ONTOGENY, JOHNS HOPKINS shall so notify ONTOGENY,
      and ONTOGENY shall exercise one of the following options within sixty (60)
      days of notification to ONTOGENY by JOHNS HOPKINS:

      (a)   commence active research and development of Licensed Patents in the
            Licensed Field of Use pursuant to Articles 2.5(viii) or 2.5(ix);

      (b)   grant a sublicense to said third parties to make, use and sell
            Licensed Products in the Licensed Field of Use pursuant to Articles
            2.5(viii) or 2.5(ix); or


                                     - 6 -
<PAGE>

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

      (c)   grant the right to JOHNS HOPKINS to directly license said third
            parties to make, use and sell Licensed Products in the Licensed
            Field of Use pursuant to Articles 2.5(viii) or 2.5(ix).

      In the event ONTOGENY selects the option outlined in Article 5.2(a),
      ONTOGENY or its Sublicensees (if any) will use reasonable effort and
      diligence to proceed with the development, manufacture, and sale or lease
      of Licensed Products in the Licensed Field of Use pursuant to Articles
      2.5(viii) or 2.5(ix) and to diligently develop markets for the Licensed
      Product in the Licensed Field of Use pursuant to Articles 2.5(viii) or
      2.5(ix). The diligence provisions of Article 5.2 above apply to the
      specific milestones or other measures of diligence that are set forth in
      paragraphs 8 and 9 of Appendix C.

5.3   Progress Report - On or before September 30 of each year until ONTOGENY or
      its Sublicensees (if any) markets a Licensed Product, ONTOGENY shall
      submit an annual report covering the preceding year ending June 30,
      regarding the progress of ONTOGENY or its Sublicensees (if any) toward
      commercial use of Licensed Product. Additionally, ONTOGENY will provide,
      upon written request from JOHNS HOPKINS, one additional interim report per
      year covering the time period subsequent the last previous annual report.
      The annual and interim reports will include, as a minimum, information
      sufficient to enable JOHNS HOPKINS to satisfy reporting requirements of
      the U.S. Government and for JOHNS HOPKINS to ascertain progress by
      ONTOGENY or its Sublicensees (if any) toward meeting the diligence
      requirements of Article 5.

                                    Article 6
                          Payments due to Johns Hopkins

6.1   In consideration for the rights granted in this Agreement, ONTOGENY will
      pay to JOHNS HOPKINS a noncreditable, nonrefundable license issue royalty
      of $[**] upon signing this Agreement ($[**] of which is considered a
      license processing fee paid to JOHNS HOPKINS), and issue to JOHNS HOPKINS
      [**] shares of ONTOGENY Common stock. At JOHNS HOPKINS' request, it may
      subsequently transfer and assign up to [**] of said ONTOGENY Common stock
      to the UNIVERSITY OF WASHINGTON, which transfer is herein consented to by
      ONTOGENY.


                                     - 7 -
<PAGE>

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

6.2   In the first three years of this Agreement, provided this Agreement is not
      terminated sooner, ONTOGENY will pay to JOHNS HOPKINS a yearly royalty of
      $[**], with the first payment due in 1997. Beginning in the year 2000 and
      until the end of the period of the Exclusive license as set forth in
      Article 3.2, ONTOGENY will pay to JOHNS HOPKINS a yearly royalty of $[**].
      Said yearly royalties will be paid to JOHNS HOPKINS by ONTOGENY by
      November 30th of each year. Yearly royalty payments made in the year 2003
      and after will be fully creditable against the earned royalties payments
      provided by Articles 6.3.

6.3   In addition, ONTOGENY will pay to JOHNS HOPKINS earned royalties on Net
      Sales as follows:

      (a)   For sale of Licensed Product covered by 2.3(a), (b) or (c) as a
            human and/or veterinary therapeutic and/or in vivo diagnostic and/or
            research reagents:

            (i)   [**]% of Net Sales of such Licensed Product by ONTOGENY, which
                  royalty will be reduced by [**]% of other royalty payments
                  made upon the sale of Licensed Product, but which royalty
                  shall be no less than [**]% of Net Sales of Licensed Product;
                  and

            (ii)  [**]% of revenues received by ONTOGENY on sales of such
                  Licensed Product by a Sublicensee.

      (b)   For sale of Licensed Product covered by 2.3(a), (b) or (c) as in
            vitro diagnostic reagents:

            (i)   [**]% of Net Sales of such Licensed Product by ONTOGENY
                  wherein Licensed Product is the sole active ingredient of kit
                  or reagent sold;

            (ii)  The product of [**]% and (A/B) on Net Sales of Combination
                  Products. Combination Products are those products in which
                  Licensed Product is one of two or more Active Ingredients. In
                  this sense, Active Ingredient shall mean those ingredients
                  essential to the Combination Product and on which ONTOGENY has
                  either, (i) an obligation to pay royalties to a third party,
                  or (ii) owns issued and/or


                                     - 8 -
<PAGE>

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

                  pending patent rights. If stand alone values are available for
                  all Active Ingredients in the Combination Product, then "A"
                  shall mean the stand alone value of the Licensed Product
                  incorporated into the Combination Product, and "B" shall mean
                  the aggregate of the stand alone values of all Active
                  Ingredients, including Licensed Product, in the Combination
                  Product. In the event that stand alone values are not
                  available for all Active Ingredients incorporated into the
                  Combination Product, then A shall mean the royalty of [**]%
                  owed JOHNS HOPKINS by ONTOGENY under this Agreement, and B
                  shall mean the aggregate of all royalties on Active
                  Ingredients incorporated into the Combination Product owed by
                  ONTOGENY to third parties. To the extent that B in this latter
                  case includes Active Ingredients covered by issued/pending
                  patents solely owned by ONTOGENY and on which ONTOGENY owes no
                  third party royalties, ONTOGENY and JOHNS HOPKINS will enter
                  into good faith negotiations to ascribe royalty values to the
                  Active Ingredients covered by such issued/pending patents; and

            (iii) [**]% of revenues received by ONTOGENY on sales of Licensed
                  Product by Sublicensee.

      (c)   For sale of Licensed Product covered by 2.3(d):

            (i)   [**]% of Net Sales of such Licensed Product by ONTOGENY; and

            (ii)  [**]% of revenues received by ONTOGENY on sales of such
                  Licensed Product by a Sublicensee.


                                     - 9 -
<PAGE>

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

      (d)   For sale of therapeutic cell preparations ("Cell Preparations")
            which could not have been made but for the Licensed Product:

            (i)   [**]% of Net Sales of Cell Preparations by ONTOGENY wherein
                  Licensed Product is the sole active ingredient used in cell
                  processing to generate the Cell Preparation;

            (ii)  The product of [**]% and (A/B) on Net Sales of Cell
                  Preparations of Combination Products. Combination Products are
                  those products in which Licensed Product is one of two or more
                  Active Ingredients. In this sense, Active Ingredient shall
                  mean those ingredients essential to the Combination Product
                  and on which ONTOGENY has either, (i) an obligation to pay
                  royalties to a third party, or (ii) owns issued and/or pending
                  patent rights. If stand alone values are available for all
                  Active Ingredients in the Combination Product, then "A" shall
                  mean the stand alone value of the Licensed Product
                  incorporated into the Combination Product, and "B" shall mean
                  the aggregate of the stand alone values of all Active
                  Ingredients, including Licensed Product, in the Combination
                  Product. In the event that stand alone values are not
                  available for all Active Ingredients incorporated into the
                  Combination Product, then A shall mean the royalty of [**]%
                  owed JOHNS HOPKINS by ONTOGENY under this Agreement, and B
                  shall mean the aggregate of all royalties on Active
                  Ingredients incorporated into the Combination Product owed by
                  ONTOGENY to third parties. To the extent that B in this latter
                  case includes Active Ingredients covered by issued/pending
                  patents solely owned by ONTOGENY and on which ONTOGENY owes no
                  third party royalties, ONTOGENY and JOHNS HOPKINS will enter
                  into good faith negotiations to ascribe royalty values to the
                  Active Ingredients covered by such issued/pending patents; and

            (iii) [**]% of revenues received by ONTOGENY on sales of Cell
                  Preparation by Sublicensee.


                                     - 10 -
<PAGE>

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

6.4   In addition, ONTOGENY will pay JOHNS HOPKINS non-creditable,
      non-refundable Milestone payments as follows:

      (a)   a one-time payment of $[**] to be made upon the first to occur of
            (i) issuance, in Licensed Patents, of patent claims in the United
            States, or (ii) allowance of a claim in Licensed Patents but
            cancelled pursuant to Article 7.5;

      (b)   for each Licensed Product to be marketed as a therapeutic, a
            one-time payment of $[**] to be made upon a filing of an
            investigational new drug application (IND) by ONTOGENY or its
            Sublicensees (if any);

      (c)   for each Licensed Product to be marketed as a therapeutic, a
            one-time payment of $[**] to be paid upon completion of Phase II
            clinical trials by ONTOGENY or its Sublicensees (if any);

      (d)   for each Licensed Product to be marketed as a therapeutic, a
            one-time payment of $[**] to be paid upon completion of Phase III
            clinical trials by ONTOGENY or its Sublicensees (if any);

      (e)   a one-time payment of $[**] to be made upon the first sale of a
            Licensed Product as an in vitro diagnostic reagent by ONTOGENY or
            its Sublicensees (if any); and

      (f)   Pursuant to ONTOGENY entering into a Sublicense, corporate
            partnership agreement or other similar strategic partnership
            agreement for development of Licensed Products to be marketed within
            the Licensed Field of Use, ONTOGENY will pay JOHNS HOPKINS, within
            sixty (60) days of execution of such partnership agreement, as
            follows:

                  (1)   If agreement involves non-cash consideration received by
                        ONTOGENY and the value of such non-cash consideration,
                        at the time the Sublicense is executed, represents
                        greater than [**]% of the total consideration received
                        by ONTOGENY, then ONTOGENY will pay JOHNS HOPKINS (i)
                        [**]%) of the value


                                     - 11 -
<PAGE>

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

                        of such non-cash consideration received by ONTOGENY and
                        (ii) any other amounts due JOHN HOPKINS pursuant to
                        Article 6.3, Article 6.4(f)(2), or Article 6.4(f)(3).
                        The value of any non-cash consideration will be
                        determined by ONTOGENY and represent a commercially
                        reasonable value (the "Ontogeny Non-Cash Value"). Within
                        90 days of receipt of (i) a copy of a newly executed
                        Sublicense agreement provided to JOHNS HOPKINS by
                        ONTOGENY under Article 14.4 and (ii) a notice from
                        ONTOGENY stating the amount of the Ontogeny Non-Cash
                        Value, JOHNS HOPKINS must notify ONTOGENY in writing
                        that JOHNS HOPKINS wishes to hire a mutually agreed upon
                        third party to determine the accuracy of the Ontogeny
                        Non-Cash Value (the "Third Party Non-Cash Value"). If
                        JOHNS HOPKINS does not notify ONTOGENY in writing within
                        such 90 day period of Johns Hopkins' intent to hire a
                        third party to determine the Third Party Non-Cash Value,
                        then JOHNS HOPKINS waives its right to hire such third
                        party in the future for such specific newly executed
                        Sublicence agreement. If the Third Party Non-Cash Value
                        is less than [**] of the Ontogeny Non-Cash Value, then
                        (i) ONTOGENY will pay JOHNS HOPKINS [**] of whichever is
                        lower of the Ontogeny Non-Cash Value or the Third Party
                        Non-Cash Value, and (ii) JOHNS HOPKINS will pay all
                        costs in connection with obtaining the Third Party
                        Non-Cash Value. If the Third Party Non-Cash Value is
                        greater than [**] of the Ontogeny Non-Cash Value, then
                        (i) ONTOGENY will pay JOHNS HOPKINS [**] of the Third
                        Party Non-Cash Value, and (ii) ONTOGENY will pay all
                        costs in connection with obtaining the Third Party
                        Non-Cash Value.


                                     - 12 -
<PAGE>

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

                  (2)   If agreement constitutes Committed Funds to ONTOGENY of
                        less than $[* * ], but greater than $[**], then JOHNS
                        HOPKINS will receive $[**].

                  (3)   If agreement constitutes Committed Funds to ONTOGENY of
                        greater than or equal to $[**], then JOHNS HOPKINS will
                        receive $[**].

                  (4)   Committed Funds shall include the sum of (i) half the
                        value of guaranteed equity payments, (ii) up-front
                        payments or other fees, and (iii) the total of
                        guaranteed research sponsorship payments. In calculating
                        Committed Funds, ONTOGENY shall keep a running total of
                        funds included within the definition of Committed Funds
                        and received from or guaranteed by each particular
                        Sublicensee. When the running total from any particular
                        Sublicensee is greater than $[**], but less than $[**],
                        ONTOGENY shall make a payment to JOHNS HOPKINS of $[**]
                        for that particular Sublicense, as under article
                        6.4(f)(2) herein. When the running total from any
                        particular Sublicensee exceeds $[**], then ONTOGENY
                        shall make a payment under Article 6.4(f)(3) to JOHNS
                        HOPKINS of an additional $[* * ] for that particular
                        Sublicense. Payments by Ontogeny under Article 6.4(f)(2)
                        and Article 6.4(f)(3) shall each only be made once with
                        respect to each particular Sublicensee.

      (g)   Pursuant to ONTOGENY entering into a Sublicense, corporate
            partnership agreement or other similar strategic partnership
            agreement for a Licensed Products approved for sale by FDA (or its
            equivalent regulatory authority) within the Licensed Field of Use,
            ONTOGENY will, within sixty (60) days of execution of such
            agreement, pay JOHNS HOPKINS [**] of all consideration received by
            ONTOGENY from the Sublicensee. The value of any consideration
            received by ONTOGENY from the Sublicensee will be determined by
            ONTOGENY and represent a commercially reasonable value (the
            "Ontogeny Consideration Value"). At JOHNS HOPKINS' option and such
            option to only be exercisable for the 90 day period after JOHN
            HOPKINS has been notified of such a Sublicense agreement, JOHN
            HOPKINS may hire a mutually agreed upon third


                                     - 13 -
<PAGE>

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

            party to determine the revised ONTOGENY Consideration Value (the
            "Third Party Consideration Value"). If the Third Party Consideration
            Value is less than [**] of the Ontogeny Consideration Value, then
            (i) ONTOGENY will pay JOHNS HOPKINS [**] of whichever is lower of
            the Ontogeny Consideration Value or the Third Party Consideration
            Value, and (ii) JOHNS HOPKINS will pay all costs in connection with
            obtaining the Third Party Consideration Value. If the Third Party
            Consideration Value is greater than [**] of the Ontogeny
            Consideration Value, then (i) ONTOGENY will pay JOHNS HOPKINS [**]
            of the Third Party Consideration Value, and (ii) ONTOGENY will pay
            all costs in connection with obtaining the Third Party Consideration
            Value.

      (h)   In consideration for the license granted in this Agreement, and in
            recognition of ONTOGENY recently entering into a Sublicense
            agreement with Biogen, Inc., ONTOGENY will pay to JOHNS HOPKINS an
            additional noncreditable, nonrefundable milestone payment of $[**]
            upon signing this Agreement.

      (i)   In consideration for the license granted in this Agreement and in
            recognition of ONTOGENY anticipating to enter into a Sublicense
            agreement with Boehringer Mannheim GmbH, ONTOGENY will pay to JOHNS
            HOPKINS an additional noncreditable, nonrefundable milestone payment
            of zero dollars ($0) upon the later of (i) signing this Agreement or
            (ii) closing the Sublicense agreement with Boehringer Mannheim.

      (j)   ONTOGENY represents that as of the Effective Date, ONTOGENY has not
            Sublicensed the Licensed Patents other than as disclosed in Article
            6.4(h) and 6.4(i).

6.5   If this Agreement is not terminated earlier in accordance with other
      provisions, ONTOGENY'S obligation to pay royalties under Article 6 will
      continue until the last to occur of:

      (a)   [**] from even date herewith, if no Licensed Patent issues covering
            sale of Licensed Product; or


                                     - 14 -
<PAGE>

      (b)   the expiration of the last patent under the Licensed Patents or
            Harvard University Patents/Applications or Columbia University
            Patents/Applications of which ONTOGENY would infringe a valid claim
            thereof by sale of Licensed Product.

6.6   ONTOGENY will calculate royalties on sales in currencies other than U.S.
      Dollars using the appropriate foreign exchange rate quoted by the
      BankBoston (Boston) foreign exchange desk, on the close of business on the
      last banking day of each calendar quarter. Royalty payments to JOHNS
      HOPKINS must be in U.S. Dollars.

                                    Article 7
                         Prosecution of Licensed Patents

7.1   JOHNS HOPKINS and ONTOGENY will share responsibility for patent
      prosecution as follows:

            JOHNS HOPKINS will lead the management of prosecution of the
      Licensed Patent using patent counsel reasonably acceptable to ONTOGENY,
      which counsel will use diligent efforts to prosecute the Licensed Patents
      in the best interest of ONTOGENY, JOHNS HOPKINS, HHMI and the UNIVERSITY
      OF WASHINGTON. JOHNS HOPKINS agrees to use reasonable efforts to keep such
      patent costs reasonable for the benefit of ONTOGENY, provided however,
      that the quality and scope of the Licensed Patent will not be jeopardized
      by such minimization. JOHNS HOPKINS will require its patent counsel to
      provide an annual patent prosecution and maintenance budget to ONTOGENY
      with reasonable period for review. If in any year ONTOGENY disputes such
      annual patent prosecution and maintenance budget proposed by JOHNS
      HOPKINS, then ONTOGENY will be responsible for all legal bills, up to the
      annual budget limit proposed by JOHNS HOPKINS, until both parties resolve
      their dispute over such patent prosecution and maintenance budget for the
      year. JOHNS HOPKINS' patent counsel will directly notify ONTOGENY and
      ONTOGENY's patent counsel, and provide ONTOGENY and ONTOGENY's patent
      counsel copies of any official communications from United States and
      foreign patent offices relating to said prosecution, as well as copies of
      relevant communications to the various patent offices so that ONTOGENY may
      be informed and appraised of the continuing prosecution of Licensed
      Patent. In addition,


                                     - 15 -
<PAGE>

      JOHNS HOPKINS shall cause ONTOGENY to be directly copied on all
      correspondence between JOHNS HOPKINS and JOHNS HOPKINS' patent counsel
      with regard to the status of any and all patents and patent applications
      comprising Licensed Patents. ONTOGENY will have reasonable opportunities
      to participate in decision making on key decisions affecting filing,
      prosecution and maintenance of the Licensed Patent, including, without
      limitation reasonable opportunity to review the abandonment of any
      Licensed Patent or claims thereof, and JOHNS HOPKINS will use reasonable
      efforts to incorporate ONTOGENY's reasonable suggestions regarding said
      prosecution. JOHNS HOPKINS will use reasonable efforts to amend any patent
      application to include claims reasonably requested by ONTOGENY to protect
      Licensed Product. No case will be abandoned without giving ONTOGENY at
      least thirty (30) days notice and opportunity to pursue the application.

7.2   Except as by mutual agreement between the parties, patent applications
      comprising the Licensed Patent are to be filed in the major world markets,
      which filing will be satisfied by filing in the following patent offices:
      United States, Canada, Japan, Australia and Europe.

7.3   If ONTOGENY demonstrates that it is not being adequately informed or
      apprised of the continuing prosecution of Licensed Patent or that ONTOGENY
      is not being provided with reasonable opportunities to participate in
      decision making as indicated in the above paragraph, ONTOGENY will assume
      lead management of the prosecution of the Licensed Patent, using patent
      counsel reasonably acceptable to JOHNS HOPKINS (such patent counsel to
      understand that both JOHNS HOPKINS and ONTOGENY are its clients), and
      ONTOGENY will thereafter provide JOHNS HOPKINS with the same safeguards
      which ONTOGENY was due under Article 7.1 (except patents shall be
      prosecuted in the best interests of the patent owners). Any such
      demonstration will involve reasonable written notice to JOHNS HOPKINS
      specifically detailing ONTOGENY'S concern, and a reasonable opportunity,
      including a 90 day cure period, for JOHNS HOPKINS to refute or cure the
      basis for ONTOGENY'S concern. ONTOGENY agrees to diligently prosecute or
      assist in prosecuting Licensed Patent. If after the cure period JOHNS
      HOPKINS and ONTOGENY still cannot agree on a cure for ONTOGENY'S concern,
      both parties agree to submit the dispute to mediation as set forth in
      Article 17 below.


                                     - 16 -
<PAGE>

7.4   Within 45 days after receipt of a statement from JOHNS HOPKINS, ONTOGENY
      will reimburse JOHNS HOPKINS for all costs incurred by JOHNS HOPKINS,
      including those costs incurred prior to the Effective Date, in connection
      with the preparation, filing and prosecution of all patent applications
      and maintenance of patents corresponding to the Invention. Such fees and
      costs shall not include costs incurred by Johns Hopkins in the use of its
      own resources, such as employee time, and shall not extend to patenting
      fees and costs incurred by Johns Hopkins after termination of this
      Agreement. ONTOGENY will provide payment authorization to JOHNS HOPKINS at
      least one (1) month before an action is due, provided that ONTOGENY has
      received timely notice of such action from JOHNS HOPKINS. For the purposes
      of this Article 7.4, notice will be considered given to ONTOGENY when
      ONTOGENY and ONTOGENY's patent counsel is copied and is in receipt of
      material sent by JOHNS HOPKINS' patent counsel. ONTOGENY will provide
      written authorization to JOHNS HOPKINS and its patent attorney in response
      to all notices sent by JOHNS HOPKINS' patent counsel. Failure to provide
      written authorization, if adequate notice was given to ONTOGENY, shall
      constitute an ONTOGENY decision not to authorize an action. In any country
      where ONTOGENY elects not to authorize an action, have a patent
      application filed or to pay expenses associated with filing, prosecuting
      or maintaining a patent application or patent, JOHNS HOPKINS may file,
      prosecute and/or maintain a patent application or patent at its own
      expense and for its own exclusive benefit and ONTOGENY thereafter shall
      not be licensed under such patent or patent application.

7.5   In the event that one or more of the Licensed Patents are the subject of a
      Declaration of Interference by the U.S. Patent and Trademark Office as
      interfering with claims in a Harvard University or Columbia University
      patent(s) or patent application(s) which is also exclusively licensed by
      ONTOGENY, JOHNS HOPKINS and the UNIVERSITY OF WASHINGTON agree to
      negotiate, in good faith, a reasonable settlement agreement simplifying
      issues involved in determining priority and/or to resolve respective
      rights with regard to any such patent applications which may ultimately be
      the subject of interference proceedings, such that a mechanism for
      terminating the interference is developed which awards priority to the
      appropriate party.


                                     - 17 -
<PAGE>

                                    Article 8
                    Royalty Reports, Payments, And Accounting

8.1   ONTOGENY will make quarterly written reports and earned royalty payments
      to JOHNS HOPKINS beginning with the first sale of a Licensed Product by
      ONTOGENY or Sublicensee. These reports and payments will be due within 45
      days after the end of each of ONTOGENY'S fiscal quarters, except for the
      last quarter of each fiscal year, the reports and payments being instead
      due 90 days after the end of ONTOGENY'S fiscal year. The report will
      include the number, description and aggregate Net Sales of Licensed
      Product as well as the calculation of royalty payments due JOHNS HOPKINS
      under Article 6.3 and 6.4 for the completed calendar year. ONTOGENY will
      also include the payment of royalties for the calendar year covered by the
      report.

8.2   ONTOGENY must keep and maintain records and cause its Sublicensees to keep
      and maintain records for a period of 3 years showing the manufacture,
      sale, use, and other disposition of products sold or otherwise disposed of
      under this Agreement. These records will include general ledger records
      showing cash receipts and expenses, and records that include production
      records, customers, serial numbers and related information in sufficient
      detail to be able to determine the royalties owed to JOHNS HOPKINS.
      ONTOGENY shall also permit and shall use reasonable efforts to cause its
      Sublicensee to permit, JOHNS HOPKINS to examine books and records when
      necessary to verify reports described in Article 8.1. JOHNS HOPKINS or its
      designee will make the examination at JOHNS HOPKINS' expense. If the audit
      reveals 5% or more under reporting of royalties due JOHNS HOPKINS,
      ONTOGENY will pay the audit costs

                                    Article 9
                             Negation Of Warranties

9.1   Nothing in this Agreement can be construed as:

      (a)   A warranty or representation by JOHNS HOPKINS, HHMI or the
            UNIVERSITY OF WASHINGTON as to the validity or scope of any Licensed
            Patent;


                                     - 18 -
<PAGE>

      (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 other patents, copyrights, or
            any other rights not included in Licensed Patents;

      (c)   An obligation to bring or prosecute actions or suits against third
            parties for infringement, except as described in Article 13; or

      (d)   Granting by implication, estoppel, or otherwise any licenses or
            rights under existing patents or other rights of JOHNS HOPKINS,
            HHMI, the UNIVERSITY OF WASHINGTON or other persons other than
            Licensed Patent, regardless of whether the patents or other rights
            are dominant or subordinate to any Licensed Patent.

9.2   EXCEPT AS EXPRESSLY SET FORTH IN THIS AGREEMENT, JOHNS HOPKINS, HHMI AND
      THE UNIVERSITY OF WASHINGTON MAKE NO REPRESENTATIONS AND EXTEND 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 MANUFACTURE, USE OR SALE OF THE LICENSED PRODUCT WILL NOT
      INFRINGE ANY PATENT, COPYRIGHT, TRADEMARK, OR OTHER RIGHTS OR ANY OTHER
      EXPRESS OR IMPLIED WARRANTIES.

                                   Article 10
                                 Indemnification

10.1  ONTOGENY will indemnify, hold harmless, and defend JOHNS HOPKINS, HHMI and
      the UNIVERSITY OF WASHINGTON and their respective trustees, officers,
      employees, students, and agents against any and all claims, liability,
      costs, loss or obligations (including without limitation, reasonable
      attorney fees and costs), based upon, arising out of, or in connection
      with this Agreement.

10.2  JOHNS HOPKINS, HHMI and the UNIVERSITY OF WASHINGTON will not be liable
      for any indirect, special, consequential, or other damages whatsoever,
      whether grounded in tort, strict liability, contract or otherwise, with
      respect to the manufacture, use or sale of a Licensed Product


                                     - 19 -
<PAGE>

      by ONTOGENY or Sublicensee. JOHNS HOPKINS, HHMI and the UNIVERSITY OF
      WASHINGTON will not have any responsibilities or liabilities whatsoever
      with respect to Licensed Product.

10.3  ONTOGENY must 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.

10.4  In addition to the foregoing, ONTOGENY must maintain, during the term of
      this Agreement, Comprehensive General Liability Insurance, including
      Products Liability Insurance, with reputable and financially secure
      insurance carrier to cover the activities of ONTOGENY and its Sublicensee.
      This insurance must provide, by the date of first clinical testing,
      minimum units of liability of $2,000,000 and must include JOHNS HOPKINS,
      HHMI and the UNIVERSITY OF WASHINGTON, their trustees, directors,
      officers, employees, students, and agents as additional insureds. This
      insurance will be written to cover claims incurred, discovered,
      manifested, or made during or after the expiration of this Agreement. At
      JOHNS HOPKINS' request, ONTOGENY will furnish a Certificate of Insurance
      evidencing primary coverage and requiring 30 days prior written notice of
      cancellation or material change to JOHNS HOPKINS. ONTOGENY will advise
      JOHNS HOPKINS, in writing, that it maintains excess liability coverage
      (following form) over primary insurance for at least the minimum limits
      set forth above. All insurance of ONTOGENY must be primary coverage;
      insurance of JOHNS HOPKINS, HHMI and the UNIVERSITY OF WASHINGTON will be
      excess and noncontributory.

                                   Article 11
                                 Product Marking

ONTOGENY will mark Licensed Product (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," if no patent on the Invention has issued and with
the numbers of the Licensed Patent when a patent has issued.


                                     - 20 -
<PAGE>

                                   Article 12
                             Use of Names And Marks

Except as otherwise required by law, ONTOGENY or its Sublicensees (if any) will
not identify JOHNS HOPKINS, HHMI or the UNIVERSITY OF WASHINGTON in any
promotional advertising or other promotional materials to be disseminated to the
public or to use the name of any faculty member, employee, or student or any
trademark, service mark, trade name, or symbol of JOHNS HOPKINS, HHMI or the
UNIVERSITY OF WASHINGTON without prior written consent from the institution
whose name is proposed to be used, which institution shall be provided with at
least five (5) business days for review or consent for such public disclosure,
which consent shall not be unreasonably withheld; provided, however, that
ONTOGENY shall have the right, without obtaining consent, to confirm the
existence and general content of this Agreement.

                                   Article 13
                  Infringement By Others: Protection Of Patents

13.1  ONTOGENY will promptly inform JOHNS HOPKINS of any suspected infringement
      of a Licensed Patent. During the Exclusive period of this Agreement, JOHNS
      HOPKINS and ONTOGENY each have the right to institute an action for
      infringement of the Licensed Patent against a third party as follows:

      (a)   If ONTOGENY and JOHNS HOPKINS agree to institute suit jointly, the
            suit will be brought in both their names, the out-of-pocket costs
            and any recovery or settlement will be divided equally. ONTOGENY and
            JOHNS HOPKINS will agree to the manner in which they exercise
            control over the action. JOHNS HOPKINS may, if it so desires, also
            be represented by and pay for separate counsel;

      (b)   If there is no agreement to institute a suit jointly, ONTOGENY may
            institute suit, and, at its option, join JOHNS HOPKINS and/or the
            UNIVERSITY OF WASHINGTON as co-plaintiff(s). If ONTOGENY decides to
            institute suit, then it will notify JOHNS HOPKINS in writing.
            ONTOGENY will pay the entire cost of litigation and be entitled to
            retain the entire amount of any recovery or settlement. However any
            recovery in excess of litigation costs, and the basis for such
            awarded recovery, will be used to


                                     - 21 -
<PAGE>

            calculate lost Net Sales, and ONTOGENY will pay JOHNS HOPKINS
            royalties as indicated in Article 6.3(a)(i), 6.3(b)(i) or (ii),
            6.3(c)(i) and 6.3(d)(i) or (ii).

13.2  Should ONTOGENY commence a suit under Article 13.1 but then decide to
      abandon the suit, it will give timely notice to JOHNS HOPKINS. The other
      party may continue prosecution of the suit if such party (not ONTOGENY)
      will pay all future expenses.

13.3  In the event that any judgment action alleging invalidity or
      noninfringement of any of the Licensed Patents shall be brought against
      ONTOGENY, JOHNS HOPKINS, at its option, shall have the right, within
      thirty (30) days after commencement of such action, to intervene and take
      over the sole defense of the action at its own expense, provided, however,
      should ONTOGENY bring an invalidity action against Licensed Patents, JOHNS
      HOPKINS may immediately defend such suit.

                                   Article 14
                           Right to further Sublicense

14.1  ONTOGENY may grant Sublicenses to Licensed Patents and Licensed Materials
      during the exclusive period of this Agreement.

14.2  Any Sublicense granted by ONTOGENY under this Agreement must be subject
      and subordinate to terms and conditions of this Agreement, except:

      (a)   The Sublicensee may further Sublicense any rights under Licensed
            Patents or Licensed Materials only as not specifically rejected in
            writing by JOHNS HOPKINS within fifteen (15) days of written
            notification of sub-Sublicense by ONTOGENY, any such rejection not
            being unreasonably made by JOHNS HOPKINS; and

      (b)   The earned royalty rate specified in the Sublicense may be at higher
            rates than the rates in this Agreement and must be commercially
            reasonable.

      Any Sublicense also will expressly include the provisions of Articles 8,
      9, 10, and 12 for the benefit of JOHNS HOPKINS, HHMI and the UNIVERSITY OF
      WASHINGTON. In the event that this Agreement is terminated, ONTOGENY,
      subject to JOHNS HOPKINS approval, will


                                     - 22 -
<PAGE>

      provide for the transfer of all obligations, including the payment of
      royalties, to JOHNS HOPKINS or its designee.

14.3  ONTOGENY will provide JOHNS HOPKINS a copy of any Sublicense granted under
      this Agreement within thirty (30) days of the effective date of the
      Sublicense.

                                   Article 15
                            Termination of Agreement

15.1  ONTOGENY may terminate this Agreement by giving JOHNS HOPKINS a 90 day
      notice in writing.

15.2  Surviving any termination by ONTOGENY are:

      (a)   ONTOGENY'S obligation to pay royalties, milestones and any other
            material obligations accrued;

      (b)   In the event that claims in any Licensed Patent or Hedgehog Patent
            Application, or in any divisions, continuations, reissues,
            reexamines, extensions, or CIPs thereof, have been canceled pursuant
            to Article 7.5 prior to termination of this Agreement, ONTOGENY
            shall nevertheless continue to pay royalties and milestones pursuant
            to Article 2.3(c) and Article 6.

      (c)   Any cause of action or claim of ONTOGENY, JOHNS HOPKINS or the
            UNIVERSITY OF WASHINGTON, accrued or to accrue, because of any
            breach or default by the other party; and

      (d)   The provisions of Articles 8, 9, 10, and 12.

15.3  JOHNS HOPKINS may terminate this Agreement if ONTOGENY:

      (a)   Is in default in payment of any material obligation or providing of
            reports;

      (b)   Is in breach of any provision of this Agreement; or

      (c)   Provides any false report;


                                     - 23 -
<PAGE>

      and ONTOGENY fails to remedy the default, breach, or false report within
      90 days after written notice by JOHNS HOPKINS.

15.4  Surviving any termination by JOHNS HOPKINS are:

      (a)   ONTOGENY'S obligation to pay royalties milestones and other payments
            accrued;

      (b)   Any cause of action or claim of ONTOGENY, JOHNS HOPKINS or the
            UNIVERSITY OF WASHINGTON, accrued or to accrue, because of any
            breach or default by the other party; and

      (c)   The provisions of Articles 8, 9, 10, and 12.

                                   Article 16
                             Assignment of Agreement

This Agreement may be assigned to Affiliates of ONTOGENY upon written approval
by JOHNS HOPKINS and UNIVERSITY OF WASHINGTON. JOHNS HOPKINS and UNIVERSITY OF
WASHINGTON will not unreasonably withhold approval. For purposes of this
Agreement, "Affiliate" shall mean any corporation or other business entity which
directly or indirectly controls, is controlled by, or is under common control
with ONTOGENY. Control means ownership or other beneficial interest in 50% or
more of the voting stock or other voting interest of a corporation or other
business entity.

                                   Article 17
                              Mediation of Disputes

17.1  In the event of any controversy or any disputed claim arising from this
      Agreement, excluding any dispute relating to patent validity or
      infringement, the Parties shall first attempt in good faith to resolve the
      dispute by discussions and/or negotiations directly involving appropriate
      representatives of such of the Parties having authority to resolve the
      dispute.

17.2  In the event direct negotiations fail, the Parties shall attempt in good
      faith to resolve the dispute by mediation. Either party may initiate a
      mediation proceeding by request in writing to the other party. Thereupon,
      both Parties will be obligated to engage in a mediation. The proceeding
      will


                                     - 24 -
<PAGE>

      be conducted in accordance with the presently effective American
      Arbitration Association (the "AAA") Commercial Mediation Rules, a copy of
      which is attached as Appendix D. If the Parties have not agreed within
      thirty (30) days of the request for mediation on the selection of a
      mediator willing to serve, the AAA, upon the request of either party,
      shall appoint a qualified mediator. Efforts to reach a settlement will
      continue until the conclusion of the proceeding, which is deemed to occur
      when (a) a written settlement is reached, or (b) the mediator concludes
      and informs the Parties that further efforts would not be useful, or (c)
      the Parties agree in good faith that an impasse has been reached, or (d)
      ninety (90) days after the selection of a mediator in the case of
      termination proceedings initiated pursuant to Article 5.1 or longer as
      reasonably required by the mediator.

17.3  In the event the dispute should fail to be resolved by mediation, either
      party may seek any available remedies under law.

                                   Article 18
                                     Notices

      Notices are to be written and:

            (i)   deposited in the United States mail, registered or certified,
                  or

            (ii)  sent via reputable overnight courier service,

      and addressed as follows:

            TO JOHNS HOPKINS:               Office of Technology Licensing
                                            Johns Hopkins University
                                            2024 E. Monument Street, Ste 2-100
                                            Baltimore, Maryland 21205

                                            Attention: Director

            TO UNIVERSITY OF WASHINGTON:    Office of Technology Transfer
                                            University of Washington
                                            1101 Northeast 45th, Suite 200
                                            Seattle, Washington 98105

                                            Attention: Karen L. Deyerle


                                     - 25 -
<PAGE>

            TO HHMI:                        Howard Hughes Medical Institute
               (for purposes of             4000 Jones Bridge Road
               Article 12 Only)             Chevy Chase, Maryland 20815

                                            Attention: Office of General Counsel

            TO ONTOGENY:                    Ontogeny, Inc.
                                            45 Moulton Street
                                            Cambridge, MA 02138

                                            Attention: CEO

            TO ONTOGENY: with a copy to     Lahive & Cockfield
                                            Sixty State Street
                                            Boston, MA 02109

                                            Attention: Matthew P. Vincent, Ph.D.

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

                                   Article 19
                            No Waiver absent writing

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

                                   Article 20
                                 Applicable Law

      This Agreement is governed by the laws of the State of Massachusetts
applicable to agreements negotiated, executed and performed within
Massachusetts.

                                   Article 21
                                   Amendments


                                     - 26 -
<PAGE>

      The parties hereto acknowledge that this Agreement sets forth the entire
Agreement and understanding of the parties hereto as to the subject matter
hereof, and shall not be subject to any change or modification except by the
execution of a written instrument subscribed to by the parties hereto.


                                     - 27 -
<PAGE>

      IN WITNESS WHEREOF, the parties have executed this Agreement by their duly
authorized officers or representatives. This Agreement may be signed in
triplicate counterparts, each of which is deemed an original.


Accepted by:

ONTOGENY, INC.                                THE JOHNS HOPKINS UNIVERSITY

/s/                                           /s/
------------------------------                ----------------------------------
Signature                                     Signature

------------------------------                ----------------------------------
Print Name                                    Print Name

------------------------------                ----------------------------------
Title                                         Title


THE UNIVERSITY OF WASHINGTON

   /s/  Robert C. Miller
------------------------------
Signature

Robert C. Miller
Director, Office of Technology Transfer


                                     - 28 -
<PAGE>

I have read and agree to abide by the terms of this Agreement


Inventors:

Philip A. Beachy                              Jeffrey Porter

/s/ Philip Beachy                             /s/ Jeffrey Porter
------------------------------                ----------------------------------
Signature                                     Signature

------------------------------                ----------------------------------
Date                                          Date


Randall T. Moon

/s/ Randall Moon
------------------------------
Signature

------------------------------
Date


                                     - 29 -
<PAGE>

                                   Appendix A

                          Hedgehog Patent Applications

o     U.S. patent application serial no. 08/349,498 filed on December 2, 1994.

o     U.S patent application serial no. 08/567,357 filed on December 4, 1995.

o     PCT application serial no. PCT/US95/15923 filed on December 4, 1995.

o     U.S. patent application serial no. ____________ [to be assigned] filed on
      October 7, 1996 with the title "Novel Hedgehog-Derived Polypeptides" and
      written by Philip A. Beachy, Randall T. Moon, and Jeffrey A. Porter.


                                     - 30 -
<PAGE>

                                   Appendix B

1.    Hedgehog genes and proteins encoded by the genes, including:

      Drosophila hedgehog
      Sonic hedgehog from mouse, frog, fish
      Xenopus Cephalic hedgehog
      Xenopus banded hedgehog
      Xenopus Hedgehog 4
      Twhh (Tiggiewinkle Hedgehog)

2.    Fragments and/or truncated forms of the above genes, including:

      Truncated forms of Banded Hedgehog, including delta N-C & N
      Truncated forms of mouse sonic hedgehog
      COOH terminal fragments of Drosophila hedgehog
      SHH-C terminal fragment
      Hh Delta 89-254


                                     - 31 -
<PAGE>

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

                                   Appendix C

                   Performance Milestones for Determination of
                Diligence in the Development of Licensed Products

1.    Human Therapeutics for Cancer. JOHNS HOPKINS has the authority to
      terminate ONTOGENY's rights to Article 2.5(i) if ONTOGENY does not meet
      the following objectives: (a) the identification of a lead compound within
      [**] of the Effective Date, (b) the submission of an IND (or equivalent)
      study within [**] of the Effective Date, (c) the commencement of Phase II
      (or equivalent) study within [**] of the Effective Date, and (d) the
      commencement of Phase III (or equivalent) study within [**] of the
      Effective Date.

2.    Human Therapeutics for Neurobiology. JOHNS HOPKINS has the authority to
      terminate ONTOGENY's rights to Article 2.5(ii) if ONTOGENY not does meet
      the following objectives: (a) the identification of a lead compound within
      [**] of the Effective Date, (b) the submission of an IND (or equivalent)
      study within [**] of the Effective Date, (c) the commencement of Phase II
      (or equivalent) study within [**] of the Effective Date, and (d) the
      commencement of Phase III (or equivalent) study within [**] of the
      Effective Date.

3.    Human Therapeutics for Skeletal. JOHNS HOPKINS has the authority to
      terminate ONTOGENY's rights to Article 2.5(iii) if ONTOGENY does not meet
      the following objectives: (a) the identification of a lead compound within
      [**] of the Effective Date, (b) the submission of an IND (or equivalent)
      study within [**] of the Effective Date, (c) the commencement of Phase II
      (or equivalent) study within [**] of the Effective Date, and (d) the
      commencement of Phase III (or equivalent) study within [**] of the
      Effective Date.

4.    Human Therapeutics for Other Areas. JOHNS HOPKINS has the authority to
      terminate ONTOGENY's rights to Article 2.5(iv) if ONTOGENY does not meet
      the following objectives: (a) the identification of a lead compound within
      [**] of the Effective Date, (b) the submission of an IND (or equivalent)
      study within [**] of the Effective Date, (c) the commencement of Phase


                                     - 32 -
<PAGE>

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

      II (or equivalent) study within [**] of the Effective Date, and (d) the
      commencement of Phase III (or equivalent) study within [**] of the
      Effective Date.

5.    Veterinary Therapeutics. JOHNS HOPKINS has the authority to terminate
      ONTOGENY's rights to Article 2.5(v) if ONTOGENY does not meet the
      following objectives: (a) the identification of a lead compound within
      [**] of the Effective Date, (b) the submission of an IND (or equivalent)
      study within [**] of the Effective Date, (c) the commencement of Phase II
      (or equivalent) study within [**] of the Effective Date, and (d) the
      commencement of Phase III (or equivalent) study within [**] of the
      Effective Date.

6.    Drug Discovery. JOHNS HOPKINS has the authority to terminate ONTOGENY's
      rights to Article 2.5(vi) if ONTOGENY does not meet the following
      objectives: (a) the identification of a lead compound within [**] of the
      Effective Date, (b) the submission of an IND (or equivalent) study within
      [**] of the Effective Date, (c) the commencement of Phase 11 (or
      equivalent) study within [**] of the Effective Date, and (d) the
      commencement of Phase III (or equivalent) study within [**] of the
      Effective Date.

7.    In Vivo Diagnostics. JOHNS HOPKINS has the authority to terminate
      ONTOGENY's rights to Article 2.5(vii) if ONTOGENY does not meet the
      following objectives: (a) the identification of a lead compound within
      [**] of the Effective Date, (b) the submission of an IND (or equivalent)
      study within [**] of the Effective Date, (c) the commencement of Phase 11
      (or equivalent) study within [**] of the Effective Date, and (d) the
      commencement of Phase III (or equivalent) study within [**] of the
      Effective Date.

8.    In Vitro Diagnostics. JOHNS HOPKINS has the authority to terminate
      ONTOGENY's rights to Article 2.5(viii) if ONTOGENY does not meet the
      following objectives: (a) the identification of a lead compound within
      [**] of the Effective Date, (b) the submission of an IND (or equivalent)
      study within [**] of the Effective Date, (c) the commencement of Phase 11
      (or equivalent) study within [**] of the Effective Date, and (d) the
      commencement of Phase III (or equivalent) study within [**] of the
      Effective Date


                                     - 33 -
<PAGE>

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

                                   Appendix C

                   Performance Milestones for Determination of
                Diligence in the Development of Licensed Products
                                   (continued)

9.    Research Reagents. JOHNS HOPKINS has the authority to terminate ONTOGENY's
      rights to Article 2.5(ix) if ONTOGENY does not initiate the sale of
      research reagents within [**] of the Effective Date.


                                     - 34 -
<PAGE>

                                   Appendix D

                                     Copy of
                     American Arbitration Association (AAA)
                           Commercial Mediation Rules
                          begins on the Following Page


                                     - 35 -
<PAGE>

                                   Commercial
53D                                Mediation Rules(1)

1.    Agreement of Parties

Whenever, by stipulation or in their contract, the parties have provided for
mediation or conciliation of existing or future disputes under the auspices of
the American Arbitration Association (AAA) or under these rules, they shall be
deemed to have made these rules, as amended and in effect as of the date of the
submission of the dispute, a part of their agreement.

2.    Initiation of Mediation

Any party or parties to a dispute may initiate mediation by filing with the AAA
a submission to mediation or a written request for mediation pursuant to these
rules, together with the appropriate administrative fee contained in the Fee
Schedule. Where there is no submission to mediation or contract providing for
mediation, a party may request the AAA to invite another party to join in a
submission to mediation. Upon receipt of such a request, the AAA will contact
the other parties involved in the dispute and attempt to obtain a submission to
mediation.

3.    Request for Mediation

A request for mediation shall contain a brief statement of the nature of the
dispute and the names, addresses, and telephone numbers of all parties to the
dispute and those who will represent them, if any, in the mediation. The
initiating party shall simultaneously file two copies of the request with the
AAA and one copy with every other party to the dispute.

--------
(1)   Reprinted with the permission of the American Arbitration Association.


                                   App. 53D-1

(Matthew Bender & Co., Inc.)                              (Rel. 8-1/93 Pub. 331)
<PAGE>

                 ALT. DISPUTE RESOLUTION       App. 53D-2

4.    Appointment of Mediator

Upon receipt of a request for mediation, the AAA will appoint a qualified
mediator to serve. Normally, a single mediator will be appointed unless the
parties agree otherwise or the AAA determines otherwise. If the agreement of the
parties names a mediator or specifies a method of appointing a mediator, that
designation or method shall be followed.

5.    Qualifications of Mediator

No person shall serve as a mediator in any dispute in which that person has any
financial or personal interest in the result of the mediation, except by the
written consent of all parties. Prior to accepting an appointment, the
prospective mediator shall disclose any circumstance likely to create a
presumption of bias or prevent a prompt meeting with the parties. Upon receipt
of such information, the AAA shall either replace the mediator or immediately
communicate the information to the parties for their comments. In the event that
the parties disagree as to whether the mediator shall serve, the AAA will
appoint another mediator. The AAA is authorized to appoint another mediator if
the appointed mediator is unable to serve promptly.

6.    Vacancies

If any mediator shall become unwilling or unable to serve, the AAA will appoint
another mediator, unless the parties agree otherwise.

7.    Representation

Any party may be represented by persons of the party's choice. The names and
addresses of such persons shall be communicated in writing to all parties and to
the AAA.


(Matthew Bender & Co., Inc.)                              (Rel. 8-1/93 Pub. 331)
<PAGE>

                 ALT. DISPUTE RESOLUTION       App. 53D-3

8.    Date, Time, and Place of Mediation

The mediator shall fix the date and the time of each mediation session. The
mediation shall be held at the appropriate regional office of the AAA, or at any
other convenient location agreeable to the mediator and the parties, as the
mediator shall determine.

9.    Identification of Matters in Dispute

At least ten days prior to the first scheduled mediation session, each party
shall provide the mediator with a brief memorandum setting forth its position
with regard to the issues that need to bc resolved. At the discretion of the
mediator, such memoranda may be mutually exchanged by the parties.

At the first session, the parties will be expected to produce all information
reasonably required for the mediator to understand the issues presented.

The mediator may require any party to supplement such information

10.   Authority of Mediator

The mediator does not have the authority to impose a settlement on the parties
but will attempt to help them reach a satisfactory resolution of their dispute.
The mediator is authorized to conduct joint and separate meetings with the
parties and to make oral and written recommendations for settlement. Whenever
necessary, the mediator may also obtain expert advice concerning technical
aspects of the dispute, provided that the parties agree and assume the expenses
of obtaining such advice. Arrangements for obtaining such advice shall be made
by the mediator or the parties, as the mediator shall determine.

The mediator is authorized to end the mediation whenever, in the judgment of the
mediator, further efforts at mediation would not contribute to a resolution of
the dispute between the parties.


(Matthew Bender & Co., Inc.)                              (Rel. 8-1/93 Pub. 331)
<PAGE>

                 ALT. DISPUTE RESOLUTION       App. 53D-4

11.   Privacy

Mediation sessions are private. The parties and their representatives may attend
mediation sessions. Other persons may attend only with the permission of the
parties and with the consent of the mediator.

12.   Confidentiality

Confidential information disclosed to a mediator by the parties or by witnesses
in the course of the mediation shall not be divulged by the mediator. All
records, reports, or other documents received by a mediator while serving in
that capacity shall be confidential. The mediator shall not be compelled to
divulge such records or to testify in regard to the mediation in any adversary
proceeding or judicial forum.

The parties shall maintain the confidentiality of the mediation and shall not
rely on, or introduce as evidence in any arbitral, judicial, or other
proceeding:

      (a)   views expressed or suggestions made by another party with respect to
            a possible settlement of the dispute;

      (b)   admissions made by another party in the course of the mediation
            proceedings;

      (c)   proposals made or views expressed by the mediator, or

      (d)   the fact that another party had or had not indicated willingness to
            accept a proposal for settlement made by the mediator.

13.   No Stenographic Record

There shall be no stenographic record of the mediation process.


(Matthew Bender & Co., Inc.)                              (Rel. 8-1/93 Pub. 331)
<PAGE>

                 ALT. DISPUTE RESOLUTION       App. 53D-5

14.   Termination of Mediation

The mediation shall be terminated:

      (a)   by the execution of a settlement agreement by the parties;

      (b)   by a written declaration of the mediator to the effect that further
            efforts at mediation are no longer worthwhile; or

      (c)   by a written declaration of a party or parties to the effect that
            the mediation proceedings are terminated.

15.   Exclusion of Liability

Neither the AAA nor any mediator is a necessary party in judicial proceedings
relating to the mediation.

Neither the AAA nor any mediator shall be liable to any party for any act or
omission in connection with any mediation conducted under these rules.

16.   Interpretation and Application of Rules

The mediator shall interpret and apply these rules insofar as they relate to the
mediator's duties and responsibilities. All other rules shall be interpreted and
applied by the AAA.

17.   Expenses

The expenses of witnesses for either side shall be paid by the party producing
such witnesses. All other expenses of the mediation, including required
traveling and other expenses of the mediator and representatives of the AAA, and
the expenses of any witness and the cost of any proofs or expert advice produced
at the direct request of the mediator, shall be borne equally by the parties
unless they agree otherwise.


(Matthew Bender & Co., Inc.)                              (Rel. 8-1/93 Pub. 331)
<PAGE>

                 ALT. DISPUTE RESOLUTION       App. 53D-6

Administrative Fees

The case filing or set-up fee is $300. This fee is to be borne equally or as
otherwise agreed by the parties.

Additionally, the parties are charged a fee based on the number of hours of
mediator time. The hourly fee is for the compensation of both the mediator and
the AAA and varies according to region. Check with your local office for
specific availability and rates.

There is no charge to the filing party where the AAA is requested to invite
other parties to join in a submission to mediation. However, if a case settles
after AAA involvement but prior to dispute resolution, the filing party will be
charged a $150 filing fee.

The expenses of the AAA and the mediator, if any, are generally borne equally by
the parties. The parties may vary this arrangement by agreement.

Where the parties have attempted mediation under these rules but have failed to
reach a settlement, the AAA will apply the administrative fee on the mediation
toward subsequent AAA arbitration, which is filed with the AAA within ninety
days of the termination of the mediation.

Deposits

Before the commencement of mediation, the parties shall each deposit such
portion of the fee covering the cost of mediation as the AAA shall direct and
all appropriate additional sums that the AAA deems necessary to defray the
expenses of the proceeding. When the mediation has terminated, the AAA shall
render an accounting and return any unexpended balance to the parties.

Refunds

Once the parties agree to mediate, no refund of the administrative fee will be
made.


(Matthew Bender & Co., Inc.)                              (Rel. 8-1/93 Pub. 331)
<PAGE>

                                  Attachment A

                             Subscription Agreement

      This Subscription Agreement (the "Subscription Agreement"), effective
September 26, 1996, is entered into by and between Ontogeny, Inc., a Delaware
corporation (the "Company") and the Johns Hopkins University (the "Investor").

      WHEREAS, the Investor desires to purchase from the Company 50,000 shares
(the "Shares") of the Company's Common Stock, par value $0.01 par value per
share;

      INTENDING TO BE LEGALLY BOUND, and in consideration of the mutual
representation, warranties, covenants and agreements contained herein and in the
License Agreement, Company and Investor hereby agree as follows:

                                    Article 1
                               Issuance of Shares

1.1   The Company agrees to sell and issue to the Investor. and the Investor
      agrees to purchase from the Company, fifty thousand (50,000) shares of
      common stock, par value $0.01 per share.

1.2   At the time of entering into this Subscription Agreement, the Company and
      the Investor shall enter into a License Agreement upon mutually agreeable
      terms in consideration of the issuance of the Shares to the Investor.

                                    Article 2
                 Representations and Warranties of the Investor

2.1   The Investor hereby represents and warrants to the Company as of the date
      of this Agreement as follows:

      (a)   The Investor (i) is an Accredited Investor as that term is defined
            in 17 CFR ss.230.501(a); (ii) has been furnished with all
            information deemed necessary by the Investor to evaluate the merits
            and risks of the Shares; (iii) has had the opportunity to ask
            questions and receive answers concerning the Company and the Shares;
            and (iv) has been given the


                                       1
<PAGE>

            opportunity to obtain any additional information necessary to verify
            the accuracy of any information obtained concerning the Company.

      (b)   Ability to Bear Risk. The Investor is in a financial position to
            hold the Shares and is able to bear the economic risk and withstand
            a complete loss of the investment in the Shares.

      (c)   Risk Factors. The Investors recognizes that the Shares as an
            investment involve an extremely high degree of risk. There can be no
            assurance that the Company will be able to meets its projected goals
            and the Company may need significant additional capital to be
            successful, which capital may not be readily available or available
            only upon terms that are substantially dilutive to the Investor.

      (d)   Sophistication. The Investor is a sophisticated investor, is able to
            fend for itself in the transactions contemplated by this Agreement,
            and has such knowledge and experience in financial and business
            matters that it is capable of evaluating the merits and risks of the
            prospective investment in the Shares.

      (e)   Suitability. The investment in the Shares is suitable for the
            Investor based upon its investment objective and financial needs,
            and the Investor has adequate net worth and means for providing for
            it current financial needs and contingencies and has no need for
            liquidity of investment with respect to the Shares.

      (f)   Overall Commitment to Illiquid Investments. The Investor's overall
            commitment to investments which are illiquid or not readily
            marketable is not disproportionate to its net worth, and investment
            in the Shares will not cause such overall commitment to become
            excessive.

      (g)   Restricted Securities. The Investor realizes that (i) none of the
            Shares have been registered under the Securities Act of 1933, as
            amended (the "Act"), (ii) the Shares are characterized under the Act
            as "restricted securities" and, therefore, cannot be sold or
            transferred unless they are subsequently registered under the Act or
            an exemption from such registration is available and (iii) there is
            presently no public market for the Shares


                                       2
<PAGE>

            and the Investor may not be able to liquidate his investment in the
            event of an emergency or pledge the Shares as collateral security
            for loans. In this connection, the Investor represents that it is
            familiar with Rule 144 promulgated under the Act, and understands
            the resale limitations imposed thereby and by the Act. Each
            certificate representing the Shares shall bear a legend
            substantially in the following form:

                  "The shares represented by this certificate have not been
                  registered under the Securities Act of 1933, as amended, and
                  may not be offered, sold or otherwise transferred, pledged or
                  hypothecated unless and until (i) such shares are registered
                  under such Act, (ii) such shares are sold pursuant to Rule
                  144, or (iii) an opinion of counsel satisfactory to the
                  Company is obtained to the effect that such registration is
                  not required."

            The forgoing legend shall be removed from the certificates
            representing any Shares, at the request of the holder thereof, at
            such time as they become eligible for resale pursuant to Rule 144(k)
            under the Securities Act.

      (h)   Exemption Reliance. The Investor has been advised that the Shares
            are not being registered under the Act or the applicable state
            securities laws but are being offered and sold pursuant to
            exemptions from such laws. The Investor understands that the
            Company's reliance on such exemptions is predicated in part upon the
            truth and accuracy of the Investor's representations in this
            Agreement.

      (i)   Investment Intent. The Investor represents and warrants that the
            Shares are being purchased for its own account, for investment and
            without the intention of reselling, redistribution or transferring
            the same, that it has made no agreement with others regarding any of
            such Shares and that its financial condition is such that it is not
            likely that it will be necessary to dispose of any such Shares in
            the foreseeable future. The above notwithstanding, Ontogeny consents
            to the transfer of up to 25,000 Shares to the University of
            Washington pursuant to Article 6.1 of the License Agreement.


                                       3
<PAGE>

                                    Article 3
                                    Covenants

3.1   The Investor agrees that:

      (a)   Transfer Restriction. The Investor will not transfer or assign this
            subscription or any of its interest herein. The Shares for which the
            Investor hereby subscribes shall be assigned or transferred only in
            accordance with all applicable laws and the provisions of Section
            3(b) below.

      (b)   Disposition of Shares. The Investor shall in no event make any
            disposition of all or any portion of the Shares which it is
            purchasing unless:

            (i)   There is then in effect a registration statement under the Act
                  covering such proposed disposition and such disposition is
                  made in accordance with said registration statement; or

            (ii)  (a) It shall have furnished the Company with an opinion of its
                  own counsel to the effect that such disposition will not
                  require registration of such shares under the Act, and (b)
                  such opinion of its counsel shall have been concurred in by
                  counsel for the Company, such concurrence not to be
                  unreasonably withheld or delayed, and the Company shall have
                  advised the Investor of such concurrence; or

            (iii) The above notwithstanding, Ontogeny consents to the transfer
                  of 25,000 Shares to the University of Washington pursuant to
                  Article 6.1 of the License Agreement.

            (iv)  No transfer of the Shares shall be effective unless and until
                  the proposed transferee makes the representations and
                  warranties to the Company contained in Article 2 above.

                                    Article 4
                                  Governing Law

4.1   The Investor agrees that this Subscription Agreement shall be enforced,
      governed and construed in all respects in accordance with the laws of the
      Commonwealth of Massachusetts.


                                       4
<PAGE>

                                    Article 5
                                     Notices

5.1   Notices are to be written and:

      (a)   deposited in the United States mail, registered or certified, or

      (b)   sent via reputable overnight courier service, and addressed as
            follows:

        TO JOHNS HOPKINS:              Office of Technology Licensing
                                       Johns Hopkins University
                                       2024 E.  Monument Street, Ste 2-100
                                       Baltimore, Maryland 21205

                                       Attention: Director

        TO ONTOGENY:                   Ontogeny, Inc.
                                       45 Moulton Street
                                       Cambridge, MA 02138

                                       Attention: CEO

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

                                    Article 6
                                  Miscellaneous

6.1   Survival of Representations and Warranties. This Agreement, and the rights
      and obligations of the Investor hereunder may be assigned by the Investor
      to any person or entity to which Shares are transferred by the Investor in
      accordance with the terms of this Agreement, and such transferee shall be
      deemed a "Purchaser" for purposes of this Agreement; provided that the
      transferee provides written notice of such assignment to the Company and
      agrees in writing to be bound by the obligations of the Purchaser
      contained herein and provided further that the transferee is not a
      competitor of the Company.

6.2   Entire Agreement. This Agreement embodies the entire agreement and
      understanding between the parties hereto with respect to the subject
      matter hereof and supersedes all prior agreements and understandings
      relating to such subject matter.


                                       5
<PAGE>

6.3   Amendments and Waivers. No term or provision of this Agreement shall be
      altered or amended except by a writing duly executed by the Company and
      the Investor. No waivers of or exceptions to any term, condition or
      provision of this Agreement, in any one or more instances, shall be deemed
      to be, or construed as, a further or continuing waiver of any such term,
      condition or provision.

6.4   Counterparts. This Agreement my be executed in one or more counterparts,
      each of which shall be deemed to be an original, but all of which shall be
      one and the same document.

6.5   Section Headings. This section headings of this Agreement are for the
      convenience of the parties and in no way alter, modify, amend, limit, or
      restrict the contractual obligations of the parties.

      IN WITNESS WHEREOF, the Investor has completed this Agreement by its duly
authorized officers or representatives and understands that this subscription is
subject to acceptance by the Company.

                                    ONTOGENY, INC.

                                          /s/  George A. Eldridge
                                    -----------------------------------
                                    Signature

                                    George A. Eldridge
                                    Vice President


THE JOHNS HOPKINS UNIVERSITY

      /s/
-----------------------------------
Signature

-----------------------------------
Print Name

-----------------------------------
Title


                                       6
<PAGE>

By signing below, the undersigned transferee makes the representations and
warranties to the Company contained in Article 2:

UNIVERSITY OF WASHINGTON


/s/
-----------------------------------
Signature

-----------------------------------
Print Name

-----------------------------------
Title


                                       7
<PAGE>

                      AMENDMENT NO. 1 TO LICENSE AGREEMENT

      This AMENDMENT No. 1 is made as of this 15th day of January, 1997, by and
between THE JOHNS HOPKINS UNIVERSITY, a body having corporate powers under the
laws of the State of Maryland ("JOHNS HOPKINS"), the University of Washington, a
body having corporate powers under the laws of the State of Washington
("UNIVERSITY OF WASHINGTON"), and ONTOGENY, INC., a Delaware corporation
("ONTOGENY").

      WHEREAS, JOHNS HOPKINS, UNIVERSITY OF WASHINGTON, and ONTOGENY are parties
to a License Agreement, dated as of September 26, 1996 (the "License
Agreement"); and

      WHEREAS JOHNS HOPKINS, UNIVERSITY OF WASHINGTON, and ONTOGENY wish to
amend the License Agreement as hereafter, provided.

      NOW, THEREFORE, in consideration of the mutual covenants of JOHNS HOPKINS,
UNIVERSITY OF WASHINGTON, and ONTOGENY and further good and valuable
consideration, the receipt and sufficiency of which are hereby acknowledged,
JOHNS HOPKINS, UNIVERSITY OF WASHINGTON, and ONTOGENY, intending to be legally
bound, hereby agree as follows:

      1. Appendix A of the License Agreement is hereby amended to read in full
as follows:

                                   Appendix A

      2. The written notices to Ontogeny, as provided for in Article 18, are
hereby amended to read as follows:

      TO ONTOGENY:              Ontogeny, Inc.
                                45 Moulton Street
                                Cambridge, MA 02138

                                Attention: CEO


                                   Page 1 of 2
<PAGE>

      TO ONTOGENY: with a copy to          Foley, Hoag & Eliot
                                           One Post Office Square
                                           Boston, MA  02109

                                           Attention: Matthew P. Vincent, Ph.D.

      3. Except as expressly amended by this Amendment No. 1, the License
Agreement shall remain in full force and effect as the same was in effect
immediately prior to the effectiveness of this Amendment No. 1.

      4. This Amendment No. 1 shall be governed by and construed on the same
basis as the License Agreement, as set forth therein.

      IN WITNESS WHEREOF, each of the parties hereto has fully executed this
Amendment No. 1 all as of the day and year first above written.


                                              ONTOGENY, INC.

                                              By:   /s/  Thomas D. Ignolia
                                                 -------------------------------
                                                 Thomas D. Ingolia, Ph.D.
                                                 Senior Vice President


THE JOHNS HOPKINS UNIVERSITY                  THE UNIVERSITY OF WASHINGTON

By:   /s/ N. Franklin Adkinson, Jr.           By:   /s/  Robert C. Miller
   ---------------------------------             -------------------------------
   N. Franklin Adkinson, Jr., M.D.               Robert C. Miller
   Interim Vice Dean for Research                Director, Office of Technology
                                                 Transfer



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