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                                                                   EXHIBIT 10.20

WHENEVER CONFIDENTIAL INFORMATION IS OMITTED HEREIN (SUCH OMISSIONS ARE DENOTED
BY AN ASTERISK*), SUCH CONFIDENTIAL INFORMATION HAS BEEN SUBMITTED SEPARATELY TO
THE SECURITIES AND EXCHANGE COMMISSION PURSUANT TO A REQUEST FOR CONFIDENTIAL
TREATMENT.

                               LICENSE AGREEMENT

       This Agreement is made and entered into this 9th day of September, 2003
(the "Effective Date") by and between Metabolix, Inc., a corporation duly
organized and existing under the laws of the State of Delaware and having its
principal office at 303 Third Street, Cambridge, Massachusetts 02142
(hereinafter referred to as "Metabolix"), and Tepha, Inc., a corporation duly
organized and existing under the laws of the State of Delaware and having its
principal office at 303 Third Street, Cambridge, Massachusetts 02142
(hereinafter referred to as "Tepha").

       WHEREAS, Metabolix is the assignee from Monsanto Company ("Monsanto") of
all right, title and interest in the Patent Rights, Biological Materials and
Know-How (all as defined herein);

       WHEREAS, Metabolix wishes to grant, and Tepha wishes to receive, license
rights to the Patent Rights, Biological Materials and Know-How; and

       WHEREAS, the grant of such license rights is subject to the prior written
approval of Monsanto, which has been obtained, and a copy of which is attached
as Appendix D for reference only.

       NOW THEREFORE, in consideration of the premises and the mutual covenants
contained herein, the parties hereto agree as follows:

1.     DEFINITIONS.

       1.1.   "Patent Rights" shall mean: (i) the U.S. and foreign patent
              applications and patents set forth in Appendix A, and the
              inventions described and/or claimed therein, and all other patent
              rights assigned to Metabolix by Monsanto not relating to plant
              crop production of PHAs shall be added to Appendix A by amendment;
              (ii) any divisionals, continuations and continuation-in-part
              applications which shall be directed to subject matter
              specifically described in such patent applications; (iii) the
              resulting U.S. and foreign patents; (iv) any reissues,
              reexaminations or extensions of such patents; and (v) all foreign
              counterparts of the above patent applications and patents. For the
              avoidance of doubt, the Patent Rights do not include any of the
              Zeneca Limited patent rights licensed to Metabolix by Monsanto in
              the Patent Sub-License Agreement dated May 14, 2001.

       1.2.   "Biological Materials" shall mean the biological materials set
              forth in Appendix B, and all Progeny and Unmodified Derivatives of
              those materials, but excluding Modifications. "Progeny" shall mean
              an unmodified descendant from the Biological Materials, such as
              virus from virus, cell from cell, or organism from organism.
              "Unmodified Derivatives" shall mean substances created by

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              Tepha which constitute an unmodified functional subunit or product
              expressed by the Biological Material(s), (some examples include:
              subclones of unmodified cell lines, purified or fractionated
              subsets of the Biological Material(s), proteins expressed by
              DNA/RNA supplied by Metabolix, or monoclonal antibodies secreted
              by a hybridoma cell line).

       1.3.   "Modifications" shall mean substances created by Tepha that
              contain/incorporate Biological Material(s).

       1.4.   "Know-How" shall mean the know-how set forth in Appendix C.

       1.5.   "Field" shall mean IN VIVO human and veterinary medical use of
              polymers falling within the Patent Rights, including, without
              limitation, tissue engineering, cell therapy, implantables,
              medical devices, wound sealants, prescription and non-prescription
              drug delivery, and contrast agents, BUT EXCLUDING (i) medical
              disposables, surgical drapes and trays, sanitary products, barrier
              contraceptives, nutritional and all other diagnostic uses and (ii)
              transgenic plant crop production of polymers. For the purpose of
              clarity, it is agreed and understood that, notwithstanding
              anything in the prior sentence to the contrary, diagnostic systems
              and/or devices used to monitor the IN VIVO use of a Licensed
              Product shall be included within the Field. For the purpose of
              determining whether a use falls within the Field, the parties
              shall apply the following guidelines: (x) regulation of a use by
              the U.S. Food and Drug Administration or other regulatory body
              shall be indicative but not presumptive that a use is an IN VIVO
              use, and (y) uses marketed only to physicians shall primarily fall
              within the Field, and (z) uses marketed directly only to consumers
              shall primarily fall outside the Field.

       1.6.   "Net Sales shall mean Tepha's billings for the use, sale, lease or
              other disposition of Licensed Products and Licensed Processes, and
              the fair market value of noncash consideration, less:

              1.6.1  discounts allowed in amounts customary in the trade;

              1.6.2  sales, tariff duties and/or use taxes directly imposed and
                     with reference to particular sales;

              1.6.3  outbound transportation prepaid or allowed; and

              1.6.4  amounts allowed or credited on returns.

       No deduction shall be made for commissions paid to individuals whether
       they be with independent sales agencies or regularly employed by Licensee
       and on its payroll, or for cost of collections. Licensed Products shall
       be considered "sold" when invoiced. "Net Sales" shall not include
       Licensed Products sold for clinical testing, research or development. If
       a Licensed Product or Licensed Process shall otherwise be distributed or
       invoiced for a discounted price substantially lower than customary in the
       trade or distributed at no cost to Tepha Affiliates or otherwise, Net
       Sales shall be based on the customary amount billed for such Licensed
       Products or Licensed Processes.

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       Where the Licensed Product is a combination product consisting of
       material whose composition or manufacture is covered by the Patent Rights
       ("Patented Material") plus other materials (such as a growth factor, but
       not, for example, filler materials) that are not covered by the Patent
       Rights, then "Net Sales" shall mean the Net Sales of the full product
       multiplied by the fully loaded manufacturing cost of the Patented
       Material divided by the total fully loaded manufacturing cost of the
       total combination product. When the Licensed Product consists of a
       combination product consisting of a component made from the Patented
       Material plus other components, then "Net Sales" shall mean Net Sales of
       the total product multiplied by the fully loaded manufacturing cost of
       the Patented Material component divided by the fully loaded manufacturing
       cost of the total product. By "fully loaded" is meant the cost of goods
       sold plus overhead allocated to production and sale thereof.

       1.7.   "Tepha" and "Metabolix" shall include "Affiliates." "Affiliates"
              shall mean a related company of Tepha or Metabolix, respectively,
              the voting stock of which is directly or indirectly at least fifty
              percent (50%) owned and controlled by Tepha or Metabolix, an
              organization which directly or indirectly controls more than fifty
              percent (50%) of the voting stock of Tepha or Metabolix, and an
              organization the majority ownership of which is directly or
              indirectly common to the ownership of Tepha or Metabolix.

       1.8.   "Licensed Process" means any process which is covered in whole or
              in part by an issued, unexpired valid claim or a pending claim
              contained in the Patent Rights in the country in which such
              process is used or in which the Licensed Product made thereby is
              used or sold.

       1.9.   "Licensed Product" means any product or part thereof which: (i) is
              covered in whole or in part by an issued, unexpired valid claim or
              a pending claim contained in the Patent Rights in the country in
              which any such product or part thereof is made, used or sold; or
              (ii) is manufactured by using a process or is employed to practice
              a process which is covered in whole or in part by an issued
              unexpired valid claim or a pending claim contained in the Patent
              Rights in the country in which a Licensed Process is used or in
              which such product or part thereof is used or sold.

2.     LICENSE GRANT AND OWNERSHIP

       2.1.   NONEXCLUSIVE LICENSE. Subject to the terms and conditions of this
              Agreement, Metabolix hereby grants to Tepha the worldwide,
              nonexclusive right and license, with the right to sublicense, in
              the Field: (i) under the Patent Rights to make, have made, use,
              lease, sell, offer for sale and import the Licensed Products and
              to practice the Licensed Processes until the expiration of the
              last to expire of the Patent Rights, unless this Agreement shall
              be sooner terminated according to the terms hereof; (ii) to make,
              have made, use, lease, sell, offer for sale, import and create
              Modifications of the Biological Materials; and (iii) to use
              Know-How.

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       2.2.   EXCLUSIVE LICENSE. Subject to the terms and conditions of this
              Agreement, Metabolix hereby grants to Tepha the worldwide,
              royalty-free, exclusive right and license, with the right to
              sublicense, in the Field to make, have made, use, lease, sell,
              offer for sale and import Modifications.

       2.3.   DELIVERY. Tepha shall have thirty (30) days after the Effective
              Date to review and make copies of the Know-How and Biological
              Materials. Metabolix makes no representations regarding the
              viability of any of the Biological Materials. After thirty (30)
              days from the Effective Date, any request to review or make copies
              of the Know-How or Biological Materials shall be at Metabolix's
              discretion.

       2.4.   OWNERSHIP OF MODIFICATIONS. Tepha hereby assigns to Metabolix all
              of its right, title and interest in and to the Modifications,
              including any and all intellectual property rights therein. Tepha
              also agrees to promptly execute all assignments and patent
              applications, and similar documents as reasonably requested by
              Metabolix. If Metabolix shall be unable to obtain Tepha's
              execution of such documents for any reason, Tepha hereby
              irrevocably appoints Metabolix and its agents as Tepha's agents
              and attorneys-in-fact to execute such documents with the same
              legal effect as if Tepha shall have executed them.

       2.5.   RIGHT TO SUBLICENSE. Tepha's right to sublicense in Paragraphs 2.1
              and 2.2 is subject to Metabolix' prior written approval during the
              period that Metabolix requires Monsanto's approval to sublicense.
              Tepha agrees to insert a provision in each sublicense that
              Metabolix is a third party beneficiary of the sublicense as to the
              sublicensed Patent Rights, with the right to enforce the
              applicable terms thereof in the event Tepha does not enforce its
              rights.

       2.6.   NO OTHER RIGHTS. Nothing in this Agreement shall be construed to
              confer any rights upon Tepha by implication, estoppel or otherwise
              beyond the express licenses granted by Metabolix or as to any
              technology or patent rights of Metabolix or any other entity other
              than the Patent Rights, Biological Materials and Know-How.

       2.7.   MONSANTO RIGHTS. Monsanto retains certain rights to Patent Rights
              as collateral in the event of default by Metabolix under a
              Security Agreement between Monsanto and Metabolix dated May 12,
              2001, and this Agreement is subject to Monsanto's rights therein.
              Monsanto has granted its approval of this Agreement in the letter
              attached as Appendix D; however, Monsanto retains all of its
              rights during the remaining term of the Security Agreement,
              including without limitation its rights to Patent Rights as
              collateral, and in the event Tepha exercises its right to
              sublicense third parties, such sublicenses shall also be subject
              to such Monsanto's rights.

3.     ROYALTIES

       3.1.   LICENSE ISSUE FEE. In partial consideration for the license rights
              granted herein, Tepha shall pay Metabolix a License Issue Fee of *
              which shall be deemed earned

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              and due as follows: * on the Effective Date, and * on each of the
              six-month, twelve-month and eighteenth-month anniversaries of the
              Effective Date; provided, however, the balance of the full amount
              of such License Issue Fee shall be due upon the raising by Tepha
              of * (cumulatively) after the Effective Date in investment capital
              and/or research and development funds in connection with the
              Patent Rights, Biological Materials and Know-How, and payment
              shall be made within thirty (30) days thereafter.

       3.2    RUNNING ROYALTIES. In partial consideration for the license rights
              granted herein, Tepha shall pay Metabolix running royalties of *
              of Net Sales by Tepha ("Running Royalty"); provided, however, the
              maximum cumulative Running Royalties due on particular Net Sales
              of any Licensed Product or Licensed Process payable by Tepha to
              Metabolix for any quarter under (i) this Agreement, and (ii) the
              sublicense from Metabolix to Tepha to certain Massachusetts
              Institute of Technology patent rights dated October 1, 1999, as
              amended, shall be * of such Net Sales, subject to any deductions
              permitted under Paragraph 3.7.

       3.3    SUBLICENSE REVENUE. Tepha shall pay Metabolix a * share of gross
              sublicensing revenue, including sublicense issue fees, milestone
              payments, license maintenance fees, royalties on net sales, and
              similar consideration, and including, for the avoidance of doubt,
              the fair market value of any sublicense rights granted in a
              multi-part transaction, but excluding research and development
              funding received by Tepha; provided, however, the maximum
              cumulative share of gross sublicensing revenue in regard to a
              particular sublicense payable by Tepha to Metabolix for any
              quarter under (i) this Agreement, and (ii) the sublicense from
              Metabolix to Tepha to certain Massachusetts Institute of
              Technology patent rights dated October 1, 1999, as amended, shall
              be * of such gross sublicensing revenue. For purposes herein,
              sublicensees' net sales shall have a parallel meaning to the
              definition of Tepha's Net Sales in Paragraph 1.6.

       3.4    PAYMENTS IN FULL. All payments due hereunder shall be paid in
              full, without deduction of taxes or other fees which may be
              imposed by any government, except as otherwise provided in
              Paragraph 1.6.2.

       3.5    NO MULTIPLE ROYALTIES. No multiple Running Royalties shall be
              payable because any Licensed Product or Licensed Process, its
              manufacture, use, sale or importation are or shall be covered by
              more than one patent application or patent licensed under this
              Agreement.

       3.6    PAYMENT. Royalty payments shall be paid in the United States
              dollars in Cambridge, Massachusetts, or at such other place as
              Metabolix may reasonably designate consistent with the laws and
              regulations controlling in any foreign country. If any currency
              conversion shall be required in connection with the payment of
              royalties hereunder, such conversion shall be made by using the
              exchange rate published in the Wall Street Journal on the last
              business day of the calendar quarterly reporting period to which
              such royalty payments relate.

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       3.7    THIRD PARTY LICENSES. To the extent that Tepha has executed or
              shall obtain subsequent to the Effective Date licenses to third
              party patents or other intellectual property that are necessary to
              manufacture or sell Licensed Products or Licensed Processes in the
              Field, Tepha may deduct from the Running Royalty due to Metabolix
              under Paragraph 3.2, * of the running royalties due on such third
              party patents or intellectual property up to an amount equal to *
              of the Running Royalties due hereunder.

       3.8    APPLICATION OF CREDITS. Any credits against Running Royalties
              permitted under this Agreement may be applied by Tepha,
              cumulatively, up to * the Running Royalties otherwise due in the
              respective quarterly accounting period; provided, Tepha may carry
              over unused credits to subsequent quarterly accounting periods.
              Notwithstanding the applicability of credits under one or more
              Paragraphs of this Agreement, the minimum Running Royalties due
              from Tepha shall be * of the Running Royalties otherwise payable,
              subject to the maximum set forth in Paragraph 3.2.

4.     PATENT PROSECUTION

       4.1.   PATENT PROSECUTION. Throughout the term of this Agreement,
              Metabolix, at its own expense, shall file, prosecute and maintain
              the Patent Rights. If Metabolix shall elect not to file, prosecute
              or maintain any Patent Right, Metabolix shall notify Tepha in
              writing with at least thirty (30) days notice prior to any filing,
              action, payment or the like being due, in which event Tepha shall
              have the right to file, prosecute or maintain such Patent Right,
              at Tepha's expense in Metabolix' name. Metabolix agrees to
              execute, and agrees to use reasonable efforts to ensure that its
              employees shall execute, all documents necessary to perfect
              filing, advance prosecution and/or effect issue of any patents
              upon any such applications. After notice of such election by
              Metabolix, Tepha shall have no further royalty obligations under
              Paragraphs 3.2 and 3.3 with respect to such patents or
              applications.

5.     RECORDS AND PAYMENTS

       5.1.   RECORDS AND AUDIT. Tepha shall keep true and accurate books of
              account containing all particulars that may be necessary for the
              purpose of showing the amounts payable to Metabolix hereunder.
              Said books of account shall be kept at Tepha's principal place of
              business and shall be open at all reasonable times for three (3)
              years following the end of the calendar year to which they
              pertain, to the inspection of Metabolix or its agents for the
              purpose of verifying Tepha's royalty statements or compliance in
              other respect with this Agreement. Should such inspection lead to
              the discovery of a greater than * discrepancy in reporting to
              Metabolix's detriment, Tepha agrees to pay the cost of such
              inspection.

       5.2.   REPORTS AND PAYMENTS. Within thirty (30) days after the end of
              each calendar quarter during the term of this Agreement, Tepha
              shall send to Metabolix a report showing the Net Sales of the
              Licensed Products and Licensed Processes,

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              including calculation of deductions, and sublicensing gross
              revenue for such quarter and shall pay the appropriate royalties
              to Metabolix.

       5.3.   INTEREST. The amounts due under Articles 3 shall, if overdue, bear
              interest until payment at a per annum rate * above * in effect at
              Fleet Bank, or its successors, on the due date. The payment of
              such interest shall not foreclose Metabolix from exercising any
              other rights it may have as a consequence of the lateness of any
              payment.

6.     DUE DILIGENCE

       6.1.   DILIGENT EFFORTS. Tepha shall use diligent efforts to bring one or
              more Licensed Products or Licensed Processes to market through a
              thorough, vigorous and diligent program for exploitation of the
              Patent Rights and shall continue active, diligent development and
              marketing efforts for one or more Licensed Products or Licensed
              Processes throughout the term of this Agreement

       6.2.   GOVERNMENTAL APPROVALS AND MARKETING OF LICENSED PRODUCTS. Tepha
              or its designees shall be responsible for obtaining all necessary
              governmental approvals for the development, production,
              distribution, sale and use of any Licensed Product, at Tepha's, or
              its designees', expense, including, without limitation, any safety
              studies. Tepha or its designees shall have sole responsibility for
              any warning labels, packaging and instructions as to the use of
              Licensed Products and for the quality control for any Licensed
              Product.

7.     INFRINGEMENT

       7.1.   NOTICE. Tepha and Metabolix shall each inform the other promptly
              in writing of any alleged or threatened infringement of the Patent
              Rights by a third party and of any available evidence thereof.

       7.2.   PURSUIT OF INFRINGERS. During the term of this Agreement, Tepha
              shall have the right, but shall not be obligated, to prosecute at
              its own expense all infringements of the Patent Rights by a third
              party in the Field by litigation or settlement discussions and, in
              furtherance of such right, Metabolix agrees that Tepha may join
              Metabolix as a party plaintiff in any such suit, without expense
              to Metabolix. The total cost of any such infringement action
              commenced solely by Tepha shall be borne by Tepha. In the event
              that Tepha shall have exercised its right to bring an action,
              Tepha shall be responsible for defending against any counterclaims
              alleging invalidity or unenforceability of a Patent Right and for
              prosecuting the action through to settlement or other final
              disposition. In the event that Tepha shall undertake the
              enforcement of the Patent Rights in the Field by litigation, Tepha
              may *.

       7.3.   If within six (6) months after having been notified of any alleged
              infringement, Tepha shall have been unsuccessful in persuading the
              alleged infringer to desist and shall not have brought and shall
              not be diligently prosecuting an infringement

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              action, or if Tepha shall notify Metabolix at any time prior
              thereto of its intention not to bring suit against any alleged
              infringer, then, and in those events, only, Metabolix shall have
              the right, but shall not be obligated, to prosecute at its own
              expense any infringement of the Patent Rights in the Field. In
              furtherance of such right, Tepha hereby agrees that Metabolix may
              include Tepha as a party plaintiff in any such suit, without
              expense to Tepha. The total cost of any such infringement action
              commenced or defended solely by Metabolix shall be borne by
              Metabolix, and Metabolix shall be responsible for defending
              against any counterclaims alleging invalidity or unenforceability
              of a Patent Right.

       7.4.   Any recovery of damages by the prosecuting party for any such suit
              shall be applied first in satisfaction of any unreimbursed
              expenses and legal fees of such party relating to the suit, and
              next toward reimbursement of Metabolix for any royalties past due
              or withheld and applied pursuant to Paragraph 7.2, if applicable.
              The balance remaining from any such recovery shall be divided with
              * to the non-prosecuting party and any remaining balance to the
              prosecuting party.

       7.5.   In the event of the institution of any suit by a third party
              against Metabolix, Tepha or its sublicensees for patent
              infringement involving the Patent Rights in the Field, the party
              sued shall promptly notify the other party in writing. Tepha shall
              have the right, but not the obligation, to defend such suit at its
              own expense. If Tepha shall elect not to defend, Tepha shall
              promptly notify Metabolix. Metabolix shall have the right, but not
              the obligation, to defend such suit at its expense.

       7.6.   If Tepha shall exercise its rights pursuant to Section 7.5 to
              defend the Patent Rights, then * until a final decision shall be
              rendered by a court or administrative tribunal of competent
              jurisdiction from which no appeal can be or is taken provided
              that:

              7.6.1  If the enforceability of all material claims in such Patent
                     Right claiming the Licensed Product or Licensed Process is
                     upheld by a court of other legal or administrative tribunal
                     from which no appeal is or can be taken, *; or

              7.6.2  If one or more claims in such Patent Right covering the
                     Licensed Product or Licensed Process shall be held to be
                     invalid or otherwise unenforceable by a court or other
                     legal or administrative tribunal in any country from which
                     no appeal is or can be taken or the scope thereof is
                     modified and, as a result such Patent Right no longer
                     offers substantial protection to a Licensed Product or
                     Licensed Process in such country, then *.

       7.7.   In any suit as either party may institute to enforce or defend the
              Patent Rights pursuant to this Agreement, the other party hereto
              shall, at the request and expense of the party initiating such
              suit, cooperate in all respects and, to the extent possible, have
              its employees testify when requested and make available relevant
              records, papers, information, samples, specimens and the like. The
              parties shall

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              keep one another informed of the status of and of their respective
              activities regarding any litigation or settlement thereof
              concerning the Patent Rights in the Field or Licensed Products or
              Licensed Processes; provided, however, that no settlement or
              consent judgement or other voluntary final disposition of any suit
              defended or action brought by a party pursuant to this Article 7
              may be entered into without the consent of the other party, such
              consent not to be unreasonably withheld or delayed.

       7.8.   Tepha, during the period of this Agreement, shall have the sole
              right in accordance with the terms and conditions herein to
              sublicense any alleged infringer for future use of the Patent
              Rights in the Field.

8.     PRODUCT LIABILITY

       8.1.   INDEMNIFICATION. Tepha shall at all times during the term of this
              Agreement and thereafter, indemnify, defend and hold Metabolix and
              Monsanto, their directors, officers, employees and Affiliates,
              harmless against all claims and expenses, arising out of the death
              of or injury to any person or persons or out of any damage to
              property and against any other claim, proceeding, demand, expense
              and liability of any kind whatsoever resulting from or relating to
              the production, manufacture, sale, use, lease, consumption or
              advertisement of the Licensed Products and/or Licensed Process(es)
              *.

       8.2.   INSURANCE. Prior to the first use of a Licensed Product for
              humans, Tepha shall obtain and carry in full force and effect
              commercial, general liability insurance, including product
              liability insurance, which shall protect Tepha, Metabolix and
              Monsanto with respect to events covered by Paragraph 8.1 above.
              Such insurance shall be written by a reputable insurance company
              authorized to do business in the Commonwealth of Massachusetts,
              shall list Metabolix and Monsanto as additional named insured
              thereunder, shall be endorsed to include product liability
              coverage and shall require thirty (30) days written notice to be
              given to Metabolix prior to any cancellation or material change
              thereof. The limits of such insurance shall not be less than * per
              occurrence with an aggregate of * for personal injury including
              death; and * per occurrence with an aggregate of * for property
              damage. Tepha shall provide Metabolix with Certificates of
              Insurance evidencing the same. Tepha shall maintain such
              commercial general liability insurance during the period that any
              Licensed Product or Licensed Process is being used, distributed or
              sold and for six (6) years thereafter.

9.     WARRANTIES AND DISCLAIMER

       9.1.   *

       9.2.   DISCLAIMER. EXCEPT AS EXPRESSLY SET FORTH IN THIS AGREEMENT:
              NEITHER PARTY, NOR THEIR RESPECTIVE DIRECTORS, OFFICERS, EMPLOYEES
              AND AFFILIATES MAKE ANY REPRESENTATIONS OR EXTEND ANY WARRANTIES
              OF ANY KIND,

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              EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO WARRANTIES
              OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, VALIDITY OF
              PATENT RIGHTS CLAIMS, ISSUED OR PENDING, AND THE ABSENCE OF LATENT
              OR OTHER DEFECTS, WHETHER OR NOT DISCOVERABLE. NOTHING IN THIS
              AGREEMENT SHALL BE CONSTRUED AS A REPRESENTATION MADE OR WARRANTY
              GIVEN BY EITHER PARTY OR BY MONSANTO THAT THE PRACTICE OF THE
              LICENSES GRANTED HEREUNDER SHALL NOT INFRINGE THE PATENT RIGHTS OR
              OTHER INTELLECTUAL OR PROPRIETARY RIGHTS OF ANY THIRD PARTY.

10.    LIMITATION OF LIABILITY

       10.1.  NO CONSEQUENTIAL DAMAGES. * IN NO EVENT SHALL METABOLIX, TEPHA, OR
              THEIR RESPECTIVE DIRECTORS, OFFICERS, EMPLOYEES AND AFFILIATES BE
              LIABLE FOR INCIDENTAL OR CONSEQUENTIAL DAMAGES OF ANY KIND,
              INCLUDING ECONOMIC DAMAGE OR INJURY TO PROPERTY AND LOST PROFITS,
              REGARDLESS OF WHETHER SUCH PARTY SHALL BE ADVISED, SHALL HAVE
              OTHER REASON TO KNOW, OR IN FACT SHALL KNOW OF THE POSSIBILITY OF
              THE FOREGOING.

11.    EXPORT CONTROLS

       11.1.  Tepha acknowledges that it is subject to United States laws and
              regulations controlling the export of technical data, computer
              software, laboratory prototypes and other commodities (including
              the Arms Export Control Act, as amended and the United States
              Department of Commerce Export Administration Regulations). The
              transfer of such items may require a license from the cognizant
              agency of the United States Government and/or written assurances
              by Tepha that Tepha shall not export data or commodities to
              certain foreign countries without prior approval of such agency.
              Metabolix neither represents that a license shall not be required
              nor that, if required, it shall be issued.

12.    NON-USE OF NAMES

       12.1.  Except as required by law or in raising funding, neither party
              shall use the names or trademarks of the other, nor any adaptation
              thereof, nor the names of any of the other party's employees, in
              any advertising, promotional or sales literature without prior
              written consent obtained from such party, or said employee, in
              each case, such consent not to be unreasonably withheld, except
              that Tepha may state that it is licensed by Metabolix, under one
              or more of the patents and/or applications comprising the Patent
              Rights. Tepha may, however, use the name of any employee of
              Metabolix who is a consultant or member of an advisory board of
              Tepha, with their permission, and provided, also, that their
              affiliation with Metabolix is identified.

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13.    DISPUTE RESOLUTION

       13.1.  Except for the right of either party to apply to a court of
              competent jurisdiction for a temporary restraining order, a
              preliminary injunction or other equitable relief to preserve the
              status quo or to prevent irreparable harm, and except for any
              dispute relating to patent validity or infringement, any and all
              claims, disputes or controversies arising under, out of or in
              connection with the Agreement, shall be mediated in good faith.
              The party raising such dispute shall promptly advise the other
              party of such claim, dispute or controversy in a writing which
              describes in reasonable detail the nature of such dispute. If the
              parties by their senior management representatives shall be unable
              to resolve the dispute within thirty (30) days, then by no later
              than forty (40) business days after the recipient has received
              such notice of dispute, each party shall have selected for itself
              a representative who shall have the authority to bind such party,
              and shall additionally have advised the other party in writing of
              the name and title of such representative. By no later than sixty
              (60) business days after the date of such notice of dispute, such
              representatives shall schedule a date for a mediation hearing with
              the Cambridge Dispute Settlement Center or Endispute Inc. in
              Cambridge, Massachusetts or another mutually agreeable mediator.
              The parties shall enter into good faith mediation and shall share
              the costs equally. If the representatives of the parties have not
              been able to resolve the dispute within thirty (30) business days
              after such mediation hearing, the parties shall have the right to
              pursue any other remedies legally available to resolve such
              dispute in either the Courts of the Commonwealth of Massachusetts,
              or in the United States District Court for the District of
              Massachusetts, to whose jurisdiction for such purposes Metabolix
              and Tepha each hereby irrevocably consents and submits.

       13.2.  Notwithstanding the foregoing, nothing in this Article shall be
              construed to waive any rights or timely performance of any
              obligations under this Agreement.

14.    CONFIDENTIALITY

       14.1.  CONFIDENTIAL INFORMATION. Both Metabolix and TEPHA agree that all
              confidential information disclosed to the other party shall be
              deemed "Confidential Information" of the disclosing party. In
              particular, "Confidential Information" shall be deemed to include,
              but not be limited to, Know-How, Biological Materials, trade
              secrets, information, ideas, inventions, materials, samples,
              processes, procedures, methods, formulations, protocols, packaging
              designs and materials, test data, future development plans,
              "Product" launch date, technological know-how and engineering,
              manufacturing, regulatory, marketing, servicing, sales, or
              financial matters relating to the disclosing party and its
              business.

       14.2.  NONDISCLOSURE AND NONUSE. During the term and thereafter each
              receiving party: (i) shall maintain all Confidential Information
              in confidence; (ii) shall not disclose any Confidential
              Information to any third party without prior written consent of
              the disclosing party except that the receiving party may disclose
              in connection

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              with consultants, subcontractors or agents or raising funding and
              technical development activities for purposes consistent with this
              Agreement pursuant to a written non-disclosure agreement with said
              parties, having terms of nondisclosure and nonuse at least as
              restrictive as those set forth herein; and (iii) shall use such
              Confidential Information only to the extent required to accomplish
              the purposes of this Agreement. A receiving party may disclose
              Confidential Information that is required to be disclosed pursuant
              to the law, by request of the FDA or other government authority or
              for medical or safety reasons, but only to the extent required to
              be disclosed by the FDA or other government authority. Both
              parties shall take precautions as each normally takes with its own
              confidential and proprietary information to prevent disclosure to
              third parties, but no less than reasonable precautions.

       14.3.  EXCEPTIONS. Both parties agree that, notwithstanding the above,
              the obligations of confidentiality and nonuse shall not apply to:

              14.3.1  Information that at the time of disclosure is, or
                      thereafter becomes, generally known to the public, through
                      no wrongful act or failure to act on the part of the
                      receiving party;

              14.3.2  Information that was known by or in the possession of the
                      receiving party at the time of receiving such information
                      from the disclosing party, as evidenced by written
                      records;

              14.3.3  Information obtained by the receiving party from a third
                      party who is not breaching a commitment of confidentiality
                      to the disclosing party by revealing such information to
                      the receiving party, as evidenced by written records; or

              14.3.4  Information that is developed independently by the
                      receiving party without use of confidential information of
                      the other party, as evidenced by written records.

       14.4.  Both Parties shall make diligent efforts to ensure that all
              employees, consultants, agents and subcontractors who may have
              access to Confidential Information of the other party, and any
              other third parties who might have access to Confidential
              Information, shall sign nondisclosure agreements consistent with
              the terms set forth in this Paragraph. No Confidential Information
              shall be disclosed to any employees, subcontractors, agents,
              consultants or third parties who do not have a need to receive
              such information for the purposes of this Agreement.

15.    TERMINATION

       15.1.  TERMINATION BY METABOLIX. If Tepha shall cease to carry on its
              business, this Agreement shall terminate effective upon notice by
              Metabolix.

       15.2.  TERMINATION FOR NONPAYMENT. Should Tepha fail to make any payment
              whatsoever due and payable to Metabolix hereunder, Metabolix shall
              have the right to terminate this Agreement effective on sixty (60)
              days' notice, unless Tepha shall make all such payments to
              Metabolix, within said sixty (60) day

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              period. Upon the expiration of the sixty (60) day period, if Tepha
              shall not have made all such payments to Metabolix, the rights,
              privileges and license granted hereunder shall automatically
              terminate.

       15.3.  TERMINATION FOR MATERIAL BREACH. Upon any material breach or
              default of this Agreement by Tepha, other than those occurrences
              set out in Paragraphs 15.1 and 15.2 hereinabove, which shall
              always take precedence in that order over any material breach or
              default referred to in this Paragraph 15.3, Metabolix shall have
              the right to terminate this Agreement and the rights, privileges
              and license granted hereunder effective on one hundred and twenty
              (120) days' notice to Tepha. Such termination shall become
              automatically effective unless Tepha shall have cured any such
              material breach or default prior to the expiration of the one
              hundred and twenty (120) day period. Upon any material breach or
              default of this Agreement by Metabolix, Tepha shall have the right
              to terminate this Agreement and the rights, privileges and license
              granted hereunder effective on one hundred and twenty (120) days'
              notice to Metabolix. Such termination shall become automatically
              effective unless Metabolix shall have cured any such material
              breach or default prior to the expiration of the one hundred and
              twenty (120) day period.

       15.4.  TERMINATION BY TEPHA. Tepha shall have the right to terminate this
              Agreement at any time on six (6) months' notice to Metabolix, and
              upon payment of all amounts due Metabolix through the effective
              date of termination.

       15.5.  DEFINITION OF EXPIRATION. For purposes of this Agreement, the term
              "expiration" shall mean expiration of the last to expire of the
              Patent Rights, and the co-terminus expiration of this Agreement,
              subject to the surviving licenses and provisions. The term
              "termination" shall mean termination of this Agreement prior to
              expiration in accordance with this Article 15.

       15.6.  EFFECTS OF TERMINATION. Upon expiration or termination of this
              Agreement for any reason: (i) nothing herein shall be construed to
              release either party from any obligation that matured prior to
              expiration or the effective date of termination; (ii) Articles 1,
              2.4, 5.1 (for three (3) years), 7.1 (as to any infringement action
              instituted prior to termination), 8, 10, 13, 14, 16.4, 16.5, 16.6
              and 17 shall survive expiration or any termination; (iii) for a
              period of six (6) months after the effective date of termination,
              Tepha and its sublicensees may sell Licensed Products in
              inventory, and complete Licensed Products in the process of
              manufacture at the time of such termination and sell the same,
              provided that Tepha shall pay the Running Royalties thereon as
              required by Article 3 of this Agreement and shall submit the
              reports required by Article 5 hereof on the sales of Licensed
              Products; (iv) if requested, each party shall immediately return
              all Confidential Information to the disclosing party and shall
              cease and refrain from any further use of such Confidential
              Information; (v) upon termination of this Agreement for any
              reason, any sublicense not then in default shall continue in full
              force and effect except that Metabolix shall be substituted in
              place of the Tepha, and Metabolix shall have no obligations under
              such sublicense beyond their

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              obligations herein; (vi) upon termination (as defined in Paragraph
              15.5), if requested by Metabolix, Tepha shall return all
              Biological Materials and Know-How; and (vii) after expiration of
              this Agreement (as defined in Paragraph15.5), Tepha shall retain a
              perpetual, irrevocable, royalty-free, non-exclusive, transferable,
              worldwide license in the Field, with the right to sublicense, to
              use the Know-How.

       15.7.  LICENSE TO METABOLIX. Upon termination of this Agreement for any
              reason (except expiration or termination by Tepha for breach by
              Metabolix under Paragraph 15.3), Tepha shall, grant and hereby
              grants Metabolix a nonexclusive license, with the right to
              sublicense, to all information then in Tepha's possession relevant
              to the commercialization of Licensed Products and/or Licensed
              Processes, including, but not limited to, research results,
              toxicology data, assays, preclinical data, prototypes,
              manufacturing processes including cell lines and unused, unexpired
              amounts of Licensed Products, clinical results, regulatory
              submissions, suppliers and customer lists. In such event Tepha
              shall receive a royalty equal to * of the gross amount of
              consideration, if any, subsequently received by Metabolix with
              respect to the Licensed Products and Licensed Processes.

16.    GENERAL

       16.1.  INTEGRATED AGREEMENT. This Agreement (including its Appendices,
              which are incorporated herein by reference) constitutes the
              complete and exclusive statement of the agreement between the
              parties, and supersedes all prior agreements, proposals,
              negotiations and communications between the parties, both oral and
              written, regarding the subject matter hereof.

       16.2.  WAIVER OR AMENDMENT. No waiver, alteration or amendment of any of
              the provisions of this Agreement shall be binding unless made in
              writing and signed by each of the parties hereto.

       16.3.  NOTICES. Any payment, notice or other communication pursuant to
              this Agreement shall be sufficiently made or given on the date of
              mailing if sent to such party by certified first class mail,
              postage prepaid, return receipt requested addressed to it at its
              address below or as it shall designate by written notice given to
              the other party.

       If to Metabolix:

              Metabolix, Inc.
              303 Third Street
              Cambridge, MA 02142
              Attn: President
              Fax: 617-492-1996

       If to Tepha:

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              Tepha, Inc.
              303 Third Street
              Cambridge, MA 02142
              Attn: President
              Fax: 617-492-1996

       All such notices, if properly addressed, shall be effective when
       received.

       16.4.  GOVERNING LAW. This Agreement shall be construed, governed,
              interpreted and applied in accordance with the laws of the
              Commonwealth of Massachusetts, without regard to conflict of laws
              principles, and as necessary the laws of the United States of
              America, except that questions affecting the construction and
              effect of any patent shall be determined by the law of the country
              in which the patent was granted. Each party agrees that venue for
              any dispute arising under this Agreement shall be Boston,
              Massachusetts, and waives any objection it has or may have in the
              future with respect to such venue.

       16.5.  FAILURE TO EXERCISE REMEDY. If either party fails to enforce any
              term of this Agreement or fails to exercise any remedy, such
              failure to enforce or exercise on that occasion shall not prevent
              enforcement or exercise on any other occasion.

       16.6.  NON-EXCLUSIVE RIGHTS. The rights and remedies of the parties
              provided in this Agreement shall not be exclusive and are in
              addition to any other rights and remedies available at law or in
              equity.

       16.7.  ASSIGNMENT. Except as expressly provided in Article 2, neither
              party shall directly or indirectly sell, transfer, assign or
              delegate in whole or in part this Agreement, or any rights,
              duties, obligations or liabilities under this Agreement
              (collectively "assign"), by operation of law or otherwise, without
              the prior written consent of the other party, such consent not to
              be unreasonably withheld or delayed; provided, however, so long as
              the assignee shall not be a competitor of the other party, either
              party shall have the right to assign without consent all of its
              rights, duties, obligations and liabilities under this Agreement
              to any Affiliate or in connection with any sale, merger,
              consolidation, recapitalization or reorganization involving in
              each case the sale of all the capital stock of the party or all or
              substantially all of the assets of such party to which this
              Agreement relates. Subject to the foregoing, this Agreement shall
              inure to the benefit of and be binding upon the permitted
              successors and assigns of Metabolix and Tepha.

       16.8.  INDEPENDENT CONTRACTORS. The parties agree that in the performance
              of this Agreement they are and shall be independent contractors.
              Nothing herein shall be construed to constitute either party as
              the agent of the other party for any purpose whatsoever, and
              neither party shall bind or attempt to bind the other party to any
              contract or the performance of any obligation or represent to any
              third party that it has any right to enter into any binding
              obligation on the other party's behalf.

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       16.9.  SEVERABILITY. The provisions of this Agreement are severable, and
              in the event that any provisions of this Agreement shall be
              determined to be invalid or unenforceable under any controlling
              body of the law, such invalidity or unenforceability shall not in
              any way affect the validity or enforceability of the remaining
              provisions hereof.

       16.10. COUNTERPARTS. This Agreement may be executed in one or more
              counterparts, each of which when executed shall be deemed to be an
              original but all of which taken together shall constitute one and
              the same agreement.

       16.11. PATENT MARKING. Tepha shall apply the patent marking notices
              required by the law of any country where Licensed Products are
              made, used, sold or imported.

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       IN WITNESS WHEREOF, the parties have duly executed this Agreement the day
and year set forth below.

Metabolix, Inc.                              Tepha, Inc.


By: /s/ Oliver P. Peoples                    By:  /s/ Simon F. Williams
    ---------------------------                   -----------------------------
Name: Oliver P. Peoples                      Name: Simon F. Williams
      -------------------------                   -----------------------------
Title: Vice President R & D                  Title: President
       ------------------------                    ----------------------------
Date: September 9, 2003                      Date: September 9, 2003
     --------------------------                   -----------------------------

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