Document:

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                                                              EXHIBIT NO. 10.5

          CONFIDENTIAL MATERIALS OMITTED AND FILED SEPARATELY WITH THE
         SECURITIES AND EXCHANGE COMMISSION. ASTERISKS DENOTE OMISSIONS.

                  RESEARCH COLLABORATION AND LICENSE AGREEMENT

                                     between

                           MERCK FROSST CANADA & CO.,

                                       And

                                 NITROMED, INC.

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                  RESEARCH COLLABORATION AND LICENSE AGREEMENT

THIS AGREEMENT effective as of the date of last signature (the "Effective Date")
between MERCK FROSST CANADA & CO., a corporate entity existing pursuant to the
laws of Nova Scotia ("MERCK") a wholly-owned subsidiary of Merck & Co., Inc., a
corporation organized and existing under the laws of New Jersey and NITROMED,
INC., a corporation organized and existing under the laws of Delaware
("NITROMED").

                                   WITNESSETH:

         WHEREAS, NITROMED has developed NITROMED Know-How (as hereinafter
defined) and has rights to Patent Rights (as hereinafter defined);

         WHEREAS, MERCK and NITROMED desire to enter into a research
collaboration to develop Licensed Products (as hereinafter defined) upon the
terms and conditions set forth herein;

         WHEREAS, MERCK desires to obtain a license under the Patent Rights and
NITROMED Know-How, upon the terms and conditions set forth herein and NITROMED
desires to grant such a license;

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

                                    ARTICLE I
                                   DEFINITIONS

         Unless specifically set forth to the contrary herein, the following
terms, whether used in the singular or plural, shall have the respective
meanings set forth below:

1.1      The term "Affiliate" shall mean (i) any corporation or business entity
         of which fifty percent (50%) or more of the securities or other
         ownership interests representing the equity, the voting stock or
         general partnership interest are owned, controlled or held, directly or
         indirectly, by MERCK or NITROMED; or (ii) any corporation or business
         entity which, directly or indirectly, owns, controls or holds fifty
         percent (50%) (or the maximum ownership interest permitted by law) or
         more of the securities or other ownership interests representing the
         equity, the voting stock or, if applicable, the general partnership
         interest, of MERCK or NITROMED.

1.2      The term "Calendar Quarter" shall mean the respective periods of three
         (3) consecutive calendar months ending on March 31, June 30, September
         30 and December 31.

1.3      The term "Calendar Year" shall mean each successive period of twelve
         (12) months commencing on January 1 and ending on December 31.

1.4      The term "Change of Control" shall mean the occurrence of any of the
         following:

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         (a)      An acquisition of any voting securities of NITROMED (the
                  "Voting Securities") by any "Person" (as the term "person" is
                  used for purposes of Section 13(d) or 14(d) of the Securities
                  Exchange Act of 1934, as amended (the "Exchange Act")),
                  immediately after which such Person has "Beneficial Ownership"
                  (within the meaning of Rule 13d-3 promulgated under the
                  Exchange Act) of more than fifty percent (50%) of the combined
                  voting power of NITROMED's then-outstanding Voting Securities;
                  or

         (b)      The consummation of:

                  (i)      A merger, consolidation or reorganization (1) with or
                           into NITROMED or a direct or indirect subsidiary of
                           NITROMED or (2) in which securities of NITROMED are
                           issued (a "Merger"), unless such Merger is a
                           "Non-Control Transaction." A "Non-Control
                           Transaction" shall mean a Merger in which the
                           stockholders of NITROMED immediately before such
                           Merger own directly or indirectly immediately
                           following such Merger at least fifty percent (50%) of
                           the combined voting power of the outstanding voting
                           securities of (x) the surviving corporation, if there
                           is no parent corporation or (y) if there is one or
                           more than one parent corporation, the ultimate parent
                           corporation;

                  (ii)     A complete liquidation or dissolution of NITROMED; or

                  (iii)    The sale or other disposition of all or substantially
                           all of the assets of NITROMED and its Affiliates
                           taken as a whole to any Person.

         Notwithstanding the foregoing, for purposes of subsection (a), (b)(i)
         and (iii) above, a Change of Control shall be deemed to exist only if
         the acquiror (together with any of its affiliates), in its most
         recently completed fiscal year, had total sales of pharmaceutical
         products in excess of [**] dollars ($[**]).

1.5      The term "Combination Product" shall mean a Licensed Product that
         includes [**].

1.6      The term "Commercially Reasonable Efforts" shall mean with respect to
         the efforts to be expended by a Party with respect to any objective,
         reasonable, diligent, good faith efforts to accomplish such objective
         as such Party would normally use to accomplish a similar objective
         under similar circumstances, it being understood and agreed that with
         respect to the research, development or commercialization of any
         NO-Enhanced COX-2 Compound or Licensed Product, such efforts shall be
         substantially equivalent to those efforts and resources commonly used
         by a Party for a product owned by it or to which it has rights, which
         product is at a similar stage in its development or product life and is
         of similar market potential taking into account efficacy, safety,
         approved labeling, the competitiveness of alternative products in the
         marketplace, the patent and other proprietary position of the product,
         the likelihood of regulatory approval given the regulatory structure
         involved, the profitability of the product including the royalties
         payable to licensors of patent or other intellectual property rights,
         alternative products and other relevant factors. Commercially
         Reasonable Efforts shall be determined on a

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         market-by-market and indication-by-indication basis for a particular
         product, and it is anticipated that the level of effort will change
         over time, reflecting changes in the status of the Licensed Product and
         the market(s) involved.

1.7      The term "Committee" shall mean the joint research and development
         committee described in Section 2.4.1.

1.8      The term "Competitive Product" shall mean product(s) containing the
         same active ingredient(s) as the Licensed Product would be considered
         substitutable for Licensed Product and [**] as measured by
         prescriptions or other similar information in the country of sale.

1.9      The term "Control" shall mean with respect to any (a) item of
         information, including, without limitation, NITROMED Know-How, or (b)
         intellectual property right, the possession (whether by ownership in
         whole or in part or license, other than pursuant to this Agreement) by
         a Party of the ability to grant to the other Party access and/or a
         license as provided herein under such item or right without violating
         the terms of any agreement or other arrangements with any Third Party.

1.10     The term "COX-2 Compound" shall mean any compound that [**] as measured
         in the human whole blood assays as described in Brideau et al., Inflamm
         Res 45:68-74 (1996).

1.11     The term "Development Work" shall mean preclinical and clinical drug
         development activities, including test method development and stability
         testing, toxicology, formulation, quality assurance/quality control
         development, statistical analysis, clinical studies and regulatory
         affairs, product approval and registration.

1.12     The term "Field" shall mean [**].

1.13     The term "First Commercial Sale" shall mean, with respect to any
         Licensed Product, the first sale for end use or consumption of such
         Licensed Product in a country after all required approvals, excluding
         pricing approvals, have been granted by the governing health authority
         of such country.

1.14     The term "Full Time Equivalent" or "FTE" shall mean the equivalent of a
         full-time scientist's work time over a twelve-month period (including
         normal vacations, sick days and holidays). The portion of an FTE year
         devoted by a scientist to the Research Program shall be determined by
         dividing the number of days during any twelve (12) month period devoted
         by such employee to the Research Program by the total number of working
         days during such twelve-month period.

1.15     The term "FTE Rate" shall mean [**] dollars ($[**]) per FTE. The FTE
         Rate shall include all personnel, equipment, reagents and all other
         expenses including support staff and overhead for or associated with an
         FTE.

1.16     The term "Improvement" shall mean any enhancement in the manufacture,
         formulation, ingredients, preparation, presentation, means of delivery,
         dosage or packaging of the Licensed Product.

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1.17     The term "Indication" shall mean the use in the treatment and/or
         prevention of diseases, conditions or disorders involving each of [**].

1.18     The term "Joint Information and Inventions" shall have the meaning set
         forth in Section 2.7.

1.19     The term "Licensed Product(s)" shall mean preparations in final form,
         either as a fixed combination or intended for concomitant
         administration, for sale by prescription, over-the-counter or any other
         method for all uses in the Field, which contain a NO-Enhanced COX-2
         Compound including, without limitation, any Combination Product.

1.20     The term "Major European Market" shall mean any one of the following
         countries: the United Kingdom, France, Germany, Italy or Spain.

1.21     The term "Major Market" shall mean any one of the following countries:
         United States, Japan, the United Kingdom, France, Germany, Italy or
         Spain.

1.22     The term "Marketing Approval" shall mean any and all approvals
         (including price and reimbursement approvals), licenses, registrations,
         or authorizations of the European Union or any country, federal, state
         or local regulatory agency, department, bureau or other government
         entity that is necessary for the manufacture, use, storage, import,
         transport and/or sale of a Licensed Product for human use in such
         jurisdiction and following which the Licensed Product may be legally
         sold in such jurisdiction.

1.23     The term "MERCK Information and Inventions" shall have the meaning set
         forth in Section 2.7.

1.24     The term "MERCK Know-How" shall mean all secret, substantial and
         identified information and materials, including but not limited to,
         discoveries, Improvements, processes, formulas, data, inventions,
         know-how and trade secrets, patentable or otherwise, which, during the
         Research Program Term, are (i) Controlled by MERCK, (ii) are not
         generally known, and (iii) in MERCK's reasonable opinion are required
         by NITROMED in the performance of its obligations under the Research
         Program.

1.25     The term "NDA" shall mean a New Drug Application and all amendments and
         supplements thereto filed with the FDA (as more fully defined in 21 CFR
         314.5 et seq.), or the equivalent application filed with any equivalent
         agency or governmental authority outside the United States (including
         any supra-national agency such as in the European Union) requiring such
         filing, including all documents, data, and other information concerning
         a pharmaceutical product which are necessary for gaining regulatory
         approval to market and sell such pharmaceutical product.

1.26     The term "Net Sales" shall mean the gross invoice price of Licensed
         Product sold by MERCK, its affiliates or sublicensees (which term does
         not include distributors which are not Affiliates of MERCK, its
         Affiliates or sublicensees) to a Third Party after deducting, if not
         previously deducted, in the amount invoiced or received:

         (a)      trade and quantity discounts;

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         (b)      returns, rebates and allowances;

         (c)      chargebacks and other amounts paid on sale or dispensing of
                  Licensed Product;

         (d)      retroactive price reductions that are actually allowed or
                  granted;

         (e)      a fixed amount equal to three percent (3%) of the amount
                  invoiced to cover bad debt, sales or excise taxes, early
                  payment cash discounts, and additional special transportation,
                  custom duties, and other governmental charges; and

         (f)      the standard inventory cost of devices or delivery systems
                  used for dispensing or administering Licensed Product which
                  accompany Licensed Product as it is sold.

         In the case of any sale of the Licensed Product(s) for consideration
         other than cash, such as barter or countertrade, Net Sales shall be
         calculated on the fair market value of the consideration received. In
         the event the Licensed Product is sold as part of a Combination
         Product, the Net Sales from the Combination Product, for the purposes
         of determining royalty payments, shall be determined by multiplying the
         Net Sales of the Combination Product during the applicable royalty
         reporting period, by the fraction, A/A+B, where A is the average sale
         price of the Licensed Product when sold separately in finished form and
         B is the average sale price of the other product(s) included in the
         Combination Product when sold separately in finished form, in each case
         during the applicable royalty reporting period or, if sales of both the
         Licensed Product and the other product(s) did not occur in such period,
         then in the most recent royalty reporting period in which sales of both
         occurred. In the event that such average sale price cannot be
         determined for both the Licensed Product and all other products(s)
         included in the Combination Product, Net Sales for the purposes of
         determining royalty payments shall be calculated by multiplying the Net
         Sales of the Combination Product by the fraction of C/C+D where C is
         the fair market value of the Licensed Product and D is the fair market
         value of all other pharmaceutical product(s) included in the
         Combination Product. In such event, MERCK shall in good faith make a
         determination of the respective fair market values of the Licensed
         Product and all other pharmaceutical products included in the
         Combination Product, and shall notify NITROMED of such determination
         and provide NITROMED with data to support such determination. NITROMED
         shall have the right to review such determination and supporting data,
         and to notify MERCK if it disagrees with such determination. If
         NITROMED does not agree with such determination and if the Parties are
         unable to agree in good faith as to such respective fair market values,
         then such matter shall be resolved in accordance with Section 9.6.

1.27     The term "NITROMED Indemnified Parties" shall have the meaning set
         forth in Section 6.4.

1.28     The term "NITROMED Information and Inventions" shall have the meaning
         set forth in Section 2.7.

1.29     The term "NITROMED Know-How" shall mean all secret, substantial and
         identified information and materials, including but not limited to,
         discoveries, Improvements, processes, formulas, data, inventions,
         know-how and trade secrets, patentable or

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         otherwise, which during the Research Program Term (i) are Controlled by
         NITROMED , (ii) are not generally known and (iii) are reasonably
         necessary or useful to MERCK in connection with the Research Program
         within the Field or the research, development, manufacture, marketing,
         use of sale of Licensed Products in the Territory.

1.30     The term "NO" shall mean nitric oxide.

1.31     The term "NO-Enhanced COX-2 Compound" shall mean [**].

1.32     The term "NO-COX-2 Compound" shall mean [**].

1.33     The term "NO-donor" shall mean [**].

1.34     The term "Other Indication" shall mean the use in the treatment and/or
         prevention of diseases, conditions or disorders other than the
         categories (i), (ii) and (iii) in Section 1.17 or those specifically
         set out therein.

1.35     The term "Party" shall mean MERCK or NITROMED; "Parties" shall mean
         MERCK OR NITROMED. As used in this Agreement, references to Third
         Parties do not include a Party or its Affiliates.

1.36     The term "Patent Rights" shall mean any and all patents and patent
         applications in the Territory (which for the purposes of this Agreement
         shall be deemed to include certificates of invention and applications
         for certificates of invention) which during the Research Program Term
         and for one (1) year thereafter are Controlled by NITROMED, including,
         but not limited to, those listed on Attachment 1.36, which: (i) claim,
         cover or relate to NO-Enhanced COX-2 Compounds or Licensed Products; or
         (ii) are divisions, continuations, continuations-in-part, reissues,
         renewals, extensions, supplementary protection certificates, utility,
         models and the like of any such patents and patent applications and
         foreign equivalents thereof.

1.37     The term "Phase I Studies" shall mean a human clinical trial in any
         country that is intended to initially evaluate the safety and/or
         pharmacological effect of a NO-Enhanced COX-2 Compound or Licensed
         Product in subjects or that would otherwise satisfy requirements of 21
         CFR 312.21(a), or its foreign equivalent.

1.38     The term "Phase III Studies" shall mean a pivotal human clinical trial
         in any country the results of which could be used to establish safety
         and efficacy of a NO-Enhanced COX-2 Compound or Licensed Product as a
         basis for a NDA or that would otherwise satisfy requirements of 21 CFR
         312.21(c), or its foreign equivalent.

1.39     The term "Project Leader" shall have the meaning set forth in Section
         2.4.3.

1.40     The term "Proprietary Information" shall mean all MERCK Know-How,
         NITROMED Know-How, and all other scientific, clinical, regulatory,
         marketing, financial and commercial information or data, whether
         communicated in writing or oral or by sensory detection, which is
         provided by one Party to the other Party in connection with this
         Agreement.

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1.41     The term "Research Information and Inventions" shall mean NITROMED
         Information and Inventions, MERCK Information and Inventions and Joint
         Information and Inventions.

1.42     The term "Research Plan" shall have the meaning set forth in Section
         2.1.

1.43     The term "Research Program" means the collaborative research effort
         between the Parties hereto to develop NO-Enhanced COX-2 Compounds and
         Licensed Products as set forth in Article II and Attachment 2.1.

1.44     The term "Research Program Term" shall have the meaning set forth in
         Section 2.8.

1.45     The term "Royalty Period" shall have the meaning set forth in Section
         5.4.1.

1.46     The term "Safety Assessment Candidate" or "SAC" shall mean a
         NO-Enhanced COX-2 Compound for human use with a scientific data package
         that at MERCK's sole discretion is evaluated and approved by the Merck
         Safety Assessment Review Committee or its successor as a development
         candidate for safety testing prior to initiation of clinical trials.

1.47     The term "Status Notice" shall mean a notice provided by NITROMED to
         MERCK that (a) requests that [**] MERCK with respect to a specific
         [**]; (b) requests that [**] Merck with respect to [**] with respect to
         a specified Indication or (c) requests that [**] MERCK with respect to
         [**] that is not being pursued by MERCK (or on its behalf) and for
         which NITROMED has [**] for conducting such research. For purpose of
         this Section 1.47 a [**] must be based on data existing at the time any
         such notice is provided.

1.48     The term "Territory" shall mean all of the countries in the world.

1.49     The term "Third Party(ies)" shall mean any person(s) or entity(ies)
         other than MERCK, NITROMED or their respective Affiliates.

1.50     The term "Valid Patent Claim" means a claim of (a) any patent
         application within the Territory included within Patent Rights and/or
         Research Information and Inventions that has been pending less than six
         (6) years from the earliest date on which such patent application
         claims priority and such patent claim has not have been cancelled,
         withdrawn or abandoned , or (b) an issued and unexpired patent included
         within the Patent Rights and/or Research Information and Inventions,
         which has not been revoked or held unenforceable or invalid by a
         decision of a court or other governmental agency of competent
         jurisdiction, unappealable or unappealed with the time allowed for
         appeal, and which has not been disclaimed, denied or admitted to be
         invalid or unenforceable through reissue or disclaimer or otherwise.

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                                   ARTICLE II
                                RESEARCH PROGRAM

2.1      GENERAL. NITROMED and MERCK shall engage in the Research Program upon
         the terms and conditions set forth in this Agreement. The activities to
         be undertaken in the course of Research Program are set forth in the
         "Research Plan" (Attachment 2.1) which may be amended from time to time
         upon the mutual written agreement of the Parties.

2.2      NITROMED SPECIFIC RESPONSIBILITIES. Under the direction of the
         Committee, NITROMED shall make available scientific and managerial
         personnel with sufficient expertise and experience necessary to
         undertake NITROMED's responsibilities, as set forth in the Research
         Plan and in the following sentence. In particular, NITROMED shall
         devote to the Research Program [**] FTEs for the [**] year of the
         Research Program Term and [**] FTEs for the [**] year and [**] FTEs for
         the [**] year of the Research Program Term, all of which shall be
         funded by MERCK according to Section 5.1 hereof. It is understood that
         the Parties through mutual agreement may increase the numbers of FTEs
         devoted to the Research Program in the second and third years.

2.3      MERCK SPECIFIC RESPONSIBILITIES. MERCK shall be responsible for
         performing all Development Work necessary to obtain Marketing Approvals
         for Licensed Products in certain countries in the Territory pursuant to
         MERCK's obligation under Section 3.4. NITROMED acknowledges and agrees
         that MERCK may use its Affiliates or Third Parties to perform certain
         of its obligations under this Agreement from time to time. MERCK shall,
         during the Research Program Term, keep NITROMED advised of its
         activities under this Section 2.3 through MERCK's Committee
         representatives during each quarterly meeting, pursuant to Section
         2.4.2.

2.4      COMMITTEE. The Parties hereby establish a Committee to facilitate the
         Research Program as follows:

2.4.1    COMPOSITION OF THE COMMITTEE. The Research Program shall be conducted
         under the direction of a joint research committee (the "Committee")
         comprised of three (3) named representatives of MERCK and three (3)
         named representatives of NITROMED. Each Party shall appoint its
         respective representatives to the Committee from time to time, and may
         substitute one or more of its representatives, in its sole discretion,
         effective upon notice to the other Party of such change. These
         representatives shall have appropriate technical credentials,
         experience and knowledge, and ongoing familiarity with the Research
         Program. Additional representatives or consultants may from time to
         time, by mutual consent of the Parties, be invited to attend Committee
         meetings, subject to compliance with Section 4.1. The Committee shall
         be chaired by a representative of MERCK. Decisions of the Committee
         shall be made by a majority of the members. In the event that the
         Committee cannot or does not, after good faith efforts, reach agreement
         on an issue within thirty (30) days after the issue is first referred
         to it, such issue shall be referred for resolution to the Chief
         Executive Officer (or a senior executive officer designated by such
         CEO) of each Party. In the event such officers, after good faith
         efforts, cannot come to a resolution, the resolution and/or course of
         conduct shall be [**];

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         provided, however, any such resolution and/or course of conduct shall
         not be inconsistent with the provisions of this Agreement or impose any
         obligation or burden [**] that is outside the scope of this Agreement.
         Each Party shall bear its own expenses related to the attendance of
         such meetings by its representatives.

2.4.2    MEETINGS. The Committee shall meet at least once each Calendar Quarter
         with the location for such meetings alternating between NITROMED and
         MERCK facilities (or such other locations as is determined by the
         Committee). Alternatively, the Committee may meet by means of
         teleconference, videoconference or other similar communications
         equipment. The Committee shall confer regarding the status of the
         Research Program, review relevant data, consider and advise on any
         technical issues that arise, consider issues of priority, and review
         and advise on any budgetary and economic matters relating to the
         Research Program which is referred to the Committee.

2.4.3    PROJECT LEADERS. MERCK and NITROMED each shall appoint a person (a
         "Project Leader") from the Committee to coordinate its part of the
         Research Program. The Project Leaders shall be the primary contact
         between the Parties with respect to the Research Program. Each Party
         shall notify the other within thirty (30) days of the date of the
         Agreement of the appointment of its Project Leader and shall notify the
         other Party as soon as practicable upon changing this appointment.

2.5      EXCHANGE OF INFORMATION. Upon execution of this Agreement, NITROMED
         shall disclose to MERCK in English and in writing all NITROMED Know-How
         not previously disclosed. During the Research Project Term, NITROMED
         shall also promptly disclose to MERCK in English and in writing on an
         ongoing basis all NITROMED Know-How. Upon the execution of this
         Agreement and on an ongoing basis during the Research Project Term,
         MERCK shall promptly disclose to NITROMED all MERCK Know-How.

2.6      RECORDS AND REPORTS.

2.6.1    RECORDS. Each Party shall maintain records, in sufficient detail and in
         good scientific manner appropriate for patent and regulatory purposes,
         which shall fully and properly reflect all work done and results
         achieved in the performance of the Research Program.

2.6.2    COPIES AND INSPECTION OF RECORDS. During the Research Program Term and
         for a period of two (2) years thereafter, MERCK shall have the right,
         during normal business hours and upon reasonable notice, to inspect and
         copy all such records of NITROMED referred to in Section 2.6.1. MERCK
         shall maintain such records and the information disclosed therein in
         confidence in accordance with Section 4.1. During the Research Program
         Term and for a period of two (2) years thereafter, MERCK shall have the
         right to arrange for its employees and/or consultants involved in the
         activities contemplated hereunder to visit NITROMED at its offices and
         laboratories during normal business hours and upon reasonable notice,
         and to discuss the Research Program work and its results in detail with
         the technical personnel and consultants of NITROMED.

2.6.3    QUARTERLY REPORTS. Within thirty (30) days following the end of each
         Calendar Quarter during the term of this Agreement, each Party shall
         provide to the other Party a written

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         progress report which shall describe (i) the work performed to date on
         the Research Program, evaluate the work performed in relation to the
         goals of the Research Program and provide such other information
         required by the Research Program or reasonably requested by the other
         Party relating to the progress of the goals or performance of the
         Research Program, and (ii) the status of the Development Work
         undertaken in the previous Calendar Quarter, PROVIDED THAT no further
         reports under this Section 2.6.3 shall be required following either a
         Change of Control or the First Commercial Sale of a Licensed Product
         for each Indication in all Major Markets. Upon written request, each
         Party shall provide to the other Party copies of the records described
         in Section 2.6.1 above; provided however that Merck may in its
         discretion make certain records available for inspection at its
         facilities without an obligation to provide copies of such records to
         NITROMED.

2.7      RESEARCH INFORMATION AND INVENTIONS. The entire right, title and
         interest in all discoveries, Improvements, processes, formulas, data,
         inventions, know-how and trade secrets, patentable or otherwise,
         arising from the Research Program (all being "Research Information and
         Inventions") developed or invented:

         (a)      solely by employees of NITROMED shall be owned solely by
                  NITROMED ("NITROMED Information and Inventions");

         (b)      solely by employees of MERCK shall be owned solely by MERCK
                  ("MERCK Information and Inventions"); and

         (c)      jointly by employees of NITROMED and MERCK shall be owned
                  jointly by NITROMED and MERCK ("Joint Information and
                  Inventions").

         NITROMED shall promptly disclose to MERCK the development, making,
         conception or reduction to practice of NITROMED Information and
         Inventions. MERCK shall disclose to NITROMED the development, making,
         conception or reduction to practice of MERCK Information and Inventions
         no later than promptly after the filing of a patent application on such
         Merck Information and Invention.

2.8      RESEARCH PROGRAM TERM. Except as otherwise provided herein, the term of
         the Research Program shall commence on the January 1, 2003 and continue
         for a period of three (3) years (the "Research Program Term"). The
         Parties may, upon mutual written agreement, extend the term of the
         Research Program for additional one (1) year periods, at least one
         hundred twenty (120) days prior to the three (3) year anniversary of
         the commencement of the Research Program and, thereafter, at least one
         hundred twenty (120) days prior to each subsequent anniversary. Upon
         any extension of the term of Research Program, if desirable, Attachment
         2.1 setting forth the Research Program shall be amended in writing by
         mutual agreement. As used throughout the Agreement any reference to
         Research Program Term shall include any extension thereof. If there is
         a Change of Control event, MERCK shall have the right , to terminate
         the Research Program by providing written notice to NITROMED within
         ninety (90) days after MERCK receives written notice of the Change of
         Control event. Any such termination by MERCK shall terminate its
         obligations under Section 5.1 and shall not terminate the Agreement.

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                                   ARTICLE III
                LICENSE; EXCHANGE OF INFORMATION; DEVELOPMENT AND
                                COMMERCIALIZATION

3.1      LICENSE GRANT.

         (a)      NITROMED hereby grants to MERCK an exclusive, royalty bearing
                  license in the Territory, with a right to sublicense as
                  provided in subsection (c) below, under Patent Rights,
                  NITROMED Information and Inventions, NITROMED's rights to the
                  Joint Information and Inventions and NITROMED Know-How to
                  practice under the Patent Rights, NITROMED Information and
                  Inventions, NITROMED's rights to the Joint Information and
                  Inventions and NITROMED Know-How, to the extent required to
                  develop, make, have made, use, sell, offer to sell or import
                  NO-Enhanced COX-2 Compounds and Licensed Product(s) in the
                  Field.

         (b)      Any of NITROMED's rights to the Patent Rights, NITROMED
                  Information and Inventions, NITROMED's rights to the Joint
                  Information and Inventions and NITROMED Know-How not
                  specifically licensed to MERCK pursuant to Section 3.1(a)
                  shall be retained by NITROMED, including, but not limited to,
                  any applications outside of the Field. NITROMED shall retain
                  only the rights necessary under Patent Rights, NITROMED
                  Information and Inventions, NITROMED's rights to the Joint
                  Information and NITROMED Know-How, in the Field, to discover,
                  develop, make and use a Licensed Product in the Territory and
                  solely for the purpose of fulfilling its obligations under the
                  Research Plan.

         (c)      MERCK shall have the right to enter into sublicenses relating
                  to the license granted in Sections 3.1(a) to Third Parties
                  and/or Affiliates. Each such sublicense shall be subject and
                  subordinate to, and consistent with, the terms and conditions
                  of this Agreement, including but not limited to provisions
                  related to confidentiality (Article IV), consequential
                  damages, commercialization and development, record-keeping and
                  audit provisions and shall provide that any such sublicensee
                  shall not further sublicense. MERCK shall remain responsible
                  for the performance of its sublicensees, and shall ensure that
                  any such sublicensees comply with the relevant provisions of
                  this Agreement. In the event of a material default by any
                  sublicensee under a sublicense agreement, MERCK will inform
                  NITROMED and take such action which in MERCK's reasonable
                  business judgment will address such default.

         (d)      MERCK hereby grants to NITROMED a non-exclusive license in the
                  Territory to practice under the MERCK Know-How (including any
                  related patents) and Merck Information and Inventions to the
                  extent required to perform its obligations under this
                  Agreement. At NITROMED's request, MERCK shall consider, on a
                  case-by-case basis, the grant of a license to NITROMED under
                  the MERCK Information and Inventions for use that (i) is
                  outside the Field and (ii) related to NO, with the Parties
                  agreeing on the terms of such license, including the amount of
                  royalty payments, if any, provided that the decision whether
                  to grant such license shall be in MERCK's sole discretion.

                                       11
<PAGE>

3.2      COVENANT NOT TO SUE. In the event the development, making, having made,
         use, sale or import by MERCK, its Affiliates and/or sublicensees of
         NO-Enhanced COX-2 Compounds and Licensed Product(s) would infringe
         during the term of this Agreement a claim of an issued patent which
         NITROMED Controls and which patent is not covered by the grant in
         Section 3.1, NITROMED hereby covenants not to sue MERCK, its
         sublicensees, successors and assigns under such issued patent with
         respect to the development, making, having made, using, selling,
         offering for sale or importing NO-Enhanced COX-2 Compounds and Licensed
         Product(s) in the Territory. NITROMED's successor and assigns shall
         agree in writing to be bound by similar terms as NITROMED under this
         Section 3.2.

3.3      SECTION 365(n) OF THE BANKRUPTCY CODE. All rights and licenses granted
         under or pursuant to any section of this Agreement are, and shall
         otherwise be deemed to be, for purposes of Section 365(n) of the U.S.
         Bankruptcy Code, licenses of rights to "intellectual property" as
         defined under Section 101(35A) of the U.S. Bankruptcy Code. The Parties
         shall retain and may fully exercise all of their respective rights and
         elections under the U.S. Bankruptcy Code. The Parties agree that MERCK,
         as a licensee of such rights under this Agreement, shall retain and may
         fully exercise all of its rights and elections under the U.S.
         Bankruptcy Code, and that upon commencement of a bankruptcy proceeding
         by or against NITROMED under the U.S. Bankruptcy Code, MERCK shall be
         entitled to a complete duplicate of or complete access to (as MERCK
         deems appropriate), any such intellectual property and all embodiments
         of such intellectual property, provided MERCK continues to fulfill its
         payment and/or royalty obligations as specified herein in full. Such
         intellectual property and all embodiments thereof shall be promptly
         delivered to MERCK (i) upon any such commencement of a bankruptcy
         proceeding upon written request therefore by MERCK, unless NITROMED
         elects to continue to perform all of its obligations under this
         Agreement or (ii) if not delivered under (i) above, upon the rejection
         of this Agreement by or on behalf of NITROMED upon written request
         therefore by MERCK. The foregoing is without prejudice to any rights
         MERCK may have arising under the U.S. Bankruptcy Code or other
         applicable law.

3.4      DEVELOPMENT AND COMMERCIALIZATION. MERCK shall use Commercially
         Reasonable Efforts, at its own expense, to undertake the Development
         Work and to commercialize a Licensed Product for each Indication (and,
         if applicable, Other Indication) in each country in the Territory where
         in MERCK's reasonable opinion it is commercially viable to do so,
         PROVIDED THAT MERCK shall undertake such Development Work and
         commercialization for each Indication (and, if applicable, Other
         Indication) in each Major Market. MERCK shall, in writing and on a
         quarterly basis, keep NITROMED advised of its activities under this
         Section 3.4 in accordance with Section 2.6.3 and shall no more
         frequently than a semi-annual basis upon the request of NITROMED hold a
         meeting for MERCK to inform NITROMED of commercialization and
         development activities for Licensed Products that occurred since the
         last such meeting and plans for the next six (6) months; provided
         however that in the event of a Change of Control, MERCK's obligations
         to meet and discuss any commercialization and development activities
         under this Section 3.4 shall cease.

                                       12
<PAGE>

3.5      EXCUSED PERFORMANCE. The obligations of MERCK with respect to any
         Licensed Product under Section 3.4 are expressly conditioned upon the
         continuing absence of any adverse condition or event relating to the
         safety or efficacy of the Licensed Product, on an
         Indication-by-Indication basis (including, if applicable, any Other
         Indication), and the obligation of MERCK to develop or market any such
         Licensed Product for an Indication shall be delayed or suspended so
         long as in MERCK's reasonable opinion any such condition or event
         exists for any such Indication. MERCK shall promptly notify NITROMED of
         such adverse conditions or events and during any such delay or
         suspension under this Section 3.5, the Parties shall on a quarterly
         basis hold a meeting to discuss the efforts undertaken by MERCK to
         remove the adverse condition or event relating to the safety or
         efficacy of the Licensed Product.

3.6      RIGHTS REVERSION. After the Research Term, if NITROMED sends a Status
         Notice to MERCK, MERCK shall, in good faith, consider such Status
         Notice and notify NITROMED in writing as soon as MERCK makes a
         determination (which shall not be later than [**] of MERCK receiving a
         Status Notice) of whether or not (i) it intends to use Commercially
         Reasonable Efforts to pursue research, development or commercialization
         of the specific NO-Enhanced COX-2 Compound specified in the Status
         Notice, (ii) it intends to use Commercially Reasonable Efforts to
         pursue research, development or commercialization of a NO-Enhanced
         COX-2 Compound or Licensed Product for the Indication or Other
         Indication specified in the Status Notice, or (iii) whether it intends
         to pursue dispute resolution under Section 9.6 regarding the Status
         Notice (a "MERCK Notice"). If MERCK indicates that it intends to use
         such Commercially Reasonable Efforts, MERCK shall, as soon as
         practicable (which shall be no later than [**] after providing the
         MERCK Notice), begin research, development or commercialization, using
         Commercially Reasonable Efforts, to research, develop and/or
         commercialize the applicable NO-Enhanced COX-2 Compound or Licensed
         Product in the applicable Indication or Other Indication. In the event
         that MERCK indicates it intends to begin research for an Other
         Indication, the parties shall promptly begin to develop a workplan and
         amendment to the Research Plan reflecting such research. If any one of
         the following events occur: (i) MERCK fails to provide a Merck Notice
         within [**] of the Status Notice, (ii) MERCK indicates in a Merck
         Notice that it does not intend to use such Commercially Reasonable
         Efforts, (iii) MERCK fails to initiate dispute resolution within [**]
         from the date of the MERCK Notice indicating it will pursue dispute
         resolution, (iv) MERCK fails to initiate research, development or
         commercialization of a Licensed Product in the applicable Indication or
         Other Indication within [**] from the date of the MERCK Notice
         indicating it will pursue such research, development or
         commercialization, or (v) after dispute resolution pursuant to Section
         9.6 MERCK is determined not to have pursued Commercially Reasonable
         Efforts, then MERCK's licenses under Section 3.1 shall become
         non-exclusive with respect to such Indication, Other Indication or
         specific NO Enhanced COX-2 Compound as applicable; provided however
         that Merck's licenses under Section 3.1 shall continue to be exclusive
         for all Indications or Other Indications with respect to any specific
         NO-Enhanced COX 2 Compound or Licensed Product that Merck is pursuing
         with Commercially Reasonable Efforts.

                                       13
<PAGE>

                                   ARTICLE IV
                         CONFIDENTIALITY AND PUBLICATION

4.1      NONDISCLOSURE OBLIGATION. All Proprietary Information disclosed by one
         Party to the other Party hereunder shall be maintained in confidence by
         the receiving Party and shall not be disclosed to a Third Party or used
         for any purpose except as set forth herein without the prior written
         consent of the other Party, except to the extent that such Proprietary
         Information:

         (a)      is known by receiving Party at the time of its receipt, and
                  not through a prior disclosure by the disclosing Party, as
                  documented by business records;

         (b)      is in the public domain through no fault of the receiving
                  Party;

         (c)      is subsequently disclosed to a receiving Party by a Third
                  Party who may lawfully do so and is not under an obligation of
                  confidentiality to the disclosing Party;

         (d)      is developed by the receiving Party independently of
                  Proprietary Information received from the other Party;

         (e)      is disclosed to governmental or other regulatory agencies in
                  order to obtain patents or to gain approval to conduct
                  clinical trials or to market Licensed Product, but such
                  disclosure may be only to the extent reasonably necessary to
                  obtain patents or authorizations;

         (f)      is deemed necessary by each Party to be disclosed to
                  sublicensees, agents, consultants, Affiliates and/or other
                  Third Parties for the research and development, manufacturing
                  and/or marketing of the Licensed Product (or for such parties
                  to determine their interest in performing such activities) in
                  accordance with this Agreement on the condition that such
                  Third Parties agree to be bound by the confidentiality
                  obligations contained this Agreement, PROVIDED the term of
                  confidentiality for such Third Parties shall be no less than
                  seven (7) years; or

         (g)      is required to be disclosed by law or court order, provided
                  that notice is promptly delivered to the other Party in order
                  to provide an opportunity to challenge or limit the disclosure
                  obligations.

         Each Party shall retain all rights to the Proprietary Information it
         provides to the other Party.

4.2      PUBLICATION. MERCK and NITROMED each acknowledge the other Party's
         interest in publishing its results to obtain recognition within the
         scientific community and to advance the state of scientific knowledge.
         Each Party also recognizes the mutual interest in obtaining valid
         patent protection and in protecting business interests and trade secret
         information. Consequently, either Party, its employees or consultants
         wishing to make a publication shall deliver to the other Party a copy
         of the proposed written publication or

                                       14
<PAGE>

         an outline of an oral disclosure at least sixty (60) days prior to
         submission for publication or presentation. The reviewing Party shall
         have the right (a) to propose modifications to the publication for
         patent reasons, trade secret reasons or business reasons or (b) to
         request a reasonable delay in publication or presentation in order to
         protect patentable information. If the reviewing Party requests a
         delay, the publishing Party shall delay submission or presentation for
         a period of ninety (90) days to enable patent applications protecting
         each Party's rights in such information to be filed in accordance with
         Article VII below. Upon expiration of such ninety (90) days, the
         publishing Party shall be free to proceed with the publication or
         presentation. If the reviewing Party requests modifications to the
         publication, the publishing Party shall edit such publication to
         prevent disclosure of trade secret or proprietary business information
         prior to submission of the publication or presentation.

4.3      PRESS RELEASE. The Parties agree that NITROMED may issue a press
         release after execution of the Agreement in a form to be mutually
         agreed upon. The Parties recognize that either Party may desire to make
         public announcements with respect to the activities undertaken pursuant
         to this Agreement. The Parties agree that any such announcement will
         not contain confidential business or technical information of the other
         Party and, if disclosure of confidential business or technical
         information is required by law or regulation, will make reasonable
         efforts to minimize such disclosure and obtain confidential treatment
         for any such information that is disclosed to a governmental agency or
         group. Each Party agrees to provide to the other Party a copy of any
         public announcement as soon as reasonably practicable under the
         circumstances prior to its scheduled release. Except under
         extraordinary circumstances, each Party shall provide the other with an
         advance copy of any press release at least five (5) business days prior
         to the scheduled disclosure. Each Party shall have the right to
         expeditiously review and indicate reasonable changes to any
         announcement regarding this Agreement or the subject matter of this
         Agreement; provided that such right of review and recommendation shall
         only apply for the first time that specific information is to be
         disclosed, and shall not apply to the subsequent disclosure of
         substantially similar information that has previously been disclosed.
         Except as otherwise required by law, the Party whose press release has
         been reviewed shall remove any information the reviewing Party
         reasonably deems to be inappropriate for disclosure.

4.4      DISCLOSURE. Either Party may disclose the terms of this Agreement to
         the extent required, in the reasonable opinion of such Party's legal
         counsel, to comply with applicable laws, including without limitation
         the rules and regulations promulgated by the United States Securities
         and Exchange Commission or any other governmental agency.
         Notwithstanding the foregoing, before disclosing this Agreement or any
         of the terms hereof pursuant to this Section 4.4, the Parties will
         consult with one another on the terms of this Agreement to be redacted
         in making any such disclosure. If a Party discloses this Agreement or
         any of the terms hereof in accordance with this Section 4.4, such Party
         agrees, at its own expense, to seek confidential treatment of the
         portions of this Agreement or such terms, as may be reasonably
         requested by the other Party.

                                       15
<PAGE>

                                    ARTICLE V
                         PAYMENTS; ROYALTIES AND REPORTS

5.0      UNITED STATES CURRENCY. Unless otherwise expressly stated herein all
         references to currency amounts as dollars or $ shall mean amounts in
         United States dollars.

5.1      RESEARCH PROGRAM FUNDING. As consideration to NITROMED for the research
         and development activities undertaken by NITROMED pursuant to this
         Agreement, MERCK shall pay to NITROMED during the Research Program
         Term, for the FTEs set forth in Section 2.2, in advance on a quarterly
         basis at the beginning of each Calendar Quarter, at the FTE Rate
         commencing upon the Effective Date. The first payment due under this
         section shall be paid within thirty (30) days of the Effective Date.

5.2      CONSIDERATION FOR LICENSE. In consideration for the licenses granted
         herein under the Patent Rights, NITROMED Information and Inventions,
         NITROMED'S rights to the Joint Information and Inventions, and NITROMED
         Know-How, upon the terms and conditions contained herein, MERCK shall
         pay to NITROMED the following amounts:

         A non-refundable technology access fee accruing      $10,000,000.
         upon execution of the Agreement

         MERCK shall pay the fee due under this Section 5.2 to NITROMED within
         thirty (30) days of the Effective Date.

5.3      MILESTONE PAYMENTS. Subject to the terms and conditions in this
         Agreement, MERCK shall pay to NITROMED the following milestone
         payments:

<TABLE>
<S>                                                           <C>
                                                                $5,000,000.
         (a)  Upon [**]                                         $[**].

         (b)  Upon [**]                                         $[**].

         (c)  Upon [**]                                         $[**].

                                                                $[**].
         (d)  Upon [**]                                         $[**].

         (e)  Upon [**]                                         $[**].

         (f)  Upon [**]

         (g)  Upon [**]

</TABLE>

                                       16
<PAGE>

         MERCK shall notify NITROMED in writing within [**] days upon the
         achievement of each milestone, such notice to be accompanied by payment
         of the appropriate milestone payment. The payment under Section 5.3(a)
         shall be made only once. The payment under the milestones described in
         Section 5.3(b) through (d) shall be made once for each individual
         Indication (by way of example, payment under Section 5.3(b) may be made
         up to [**] times, once for each Indication in subsections (i) - (iii)
         in Section 1.17) and the milestone described in Sections 5.3(e) through
         (g) shall be paid as follows: (i) each of such milestones shall be
         payable no more than [**] for each Indication, irrespective of the
         number of Licensed Products for which such milestone is achieved; (ii)
         with respect to each Licensed Product, each of such milestones shall be
         payable only upon the first occurrence of such milestone for each
         Indication; (iii) for no more than [**] Indications for a specific
         Licensed Product; (iv) for purpose of the foregoing, Licensed Products
         which contain the same [**] shall be considered to be the same Licensed
         Product; and (v) as a result of the foregoing limitations, each of such
         milestones shall be payable a maximum of [**] times. For example, if
         Licensed Product X is developed for [**] Indications, the milestones
         are paid for each of such Indications; if Licensed Product Y is
         developed for all [**] Indications and is developed as well for an
         additional disease state within one of these Indications, the
         milestones are paid for the [**] Indications, [**].

5.4      ROYALTIES.

5.4.1    ROYALTIES PAYABLE BY MERCK. Subject to the terms and conditions of this
         Agreement, MERCK shall pay to NITROMED royalties on a Licensed
         Product-by-Licensed Product basis the following amounts.

<TABLE>
<S>     <C>                                                                         <C>
         (a)  For the initial [**] dollars of sales of each Licensed Product in     [**] percent
              the Territory in a Calendar Year by MERCK, its Affiliates or          ([**]%) of
              sublicensees                                                          Net Sales

         (b)  For those sales greater than [**] dollars and less than or equal      [**] percent
              to [**] dollars of each Licensed Product in the Territory in a        ([**]%) of
              Calendar Year by MERCK, its Affiliates or sublicensees                 Net Sales

         (c)  For those sales greater than [**] dollars and less than or equal      [**] percent
              to [**] dollars of each Licensed Product in the Territory in a        ([**]%) of
              Calendar Year by  MERCK, its Affiliates or sublicensees               Net Sales

         (d)  For those sales over [**] dollars of each Licensed Product in the     [**] percent
              Territory in a Calendar Year by MERCK, its Affiliates or              ([**]%) of
              sublicensees                                                          Net Sales
</TABLE>

         Royalties on each Licensed Product at the rate set forth above shall
         continue on a country-by-country basis until the expiration of the
         later of: (i) last-to-expire patent with a Valid Patent Claim that
         would be infringed by the use or sale of such Licensed

                                       17
<PAGE>

         Product in such country but for the licenses granted herein; or (ii)
         for a period of ten (10) years after First Commercial Sale of such
         Licensed Product in such country (the "Royalty Period"). In those
         countries of the Territory where (A) there are no Patent Rights
         containing a Valid Patent Claim that would be infringed by the use or
         sale of the Licensed Product in such country, or (B) when the last
         Valid Patent Claim expires during the Royalty Period, royalties shall
         be paid at [**] percent of the rates set forth in (a) to (d) above
         (calculated as the last sales made in the Territory for the Calendar
         Quarter). All royalties are subject to the following conditions:

                  (a) that only one royalty shall be due with respect to the
         same unit of Licensed Product;

                  (b) that no royalties shall be due upon the sale or other
         transfer among MERCK, its Affiliates or sublicensees, but in such cases
         the royalty shall be due and calculated upon MERCK's or its Affiliate's
         or its sublicense's Net Sales to a Third Party;

                  (c) no royalties shall accrue on the disposition of Licensed
         Product in reasonable quantities by MERCK, Affiliates or its
         sublicenses as samples (promotion or otherwise) or as donations (for
         example, to non-profit institutions or government agencies for a
         non-commercial purpose); and

                  (d) for purposes of aggregating sales on a Licensed
         Product-by-Licensed Product basis, a Licensed Product shall include all
         products [**]

5.4.2    ROYALTY PAYABLE UNDER MANAGED PHARMACEUTICAL CONTRACT. It is understood
         by the Parties that MERCK may sell Licensed Product(s) to an
         independent Third Party (such as a retailer or wholesaler) and may
         subsequently perform services relating to Licensed Product(s) and other
         products under a managed pharmaceutical benefits contract or other
         similar contract. In such cases, it is agreed by the Parties that Net
         Sales shall be based on the invoice price to an independent retailer or
         wholesaler, as set forth in Section 1.26, notwithstanding that MERCK
         may receive compensation arising from the performance of such services.

5.4.3    CHANGE IN SALES PRACTICES. The Parties acknowledge that during the term
         of this Agreement, MERCK's sales practices for the marketing and
         distribution of Licensed Product may change to the extent to which the
         calculation of the payment for royalties on Net Sales may become
         impractical or even impossible. In such event the Parties agree to meet
         and discuss in good faith new ways of compensating NITROMED to the
         extent currently contemplated under Section 5.4.1; provided, however,
         if the Parties cannot agree in new ways of compensating NITROMED, the
         terms of this Agreement shall remain in full force and effect.

5.4.4    ROYALTIES FOR BULK NO-ENHANCED COX-2 COMPOUND. In those cases where
         MERCK sells bulk NO-Enhanced COX-2 Compound rather than Licensed
         Product in packaged form to an independent Third Party, the royalty
         obligations of this Article V shall be applicable to the bulk
         NO-Enhanced COX-2 Compound; provided however that if MERCK obtains
         additional compensation relating to either (i) use or commercialization
         of such bulk NO-Enhanced COX-2 Compound, or (ii) sublicensing
         intellectual property rights granted to MERCK in Article III, then the
         Parties agree that there shall be

                                       18
<PAGE>

         additional compensation to NITROMED in an amount to be mutually agreed
         upon by the Parties.

5.4.5.   COMPULSORY LICENSES. If a compulsory license is granted to a Third
         Party with respect to Licensed Product in any country in the Territory
         [**] provided by Section 5.4.1., then the royalty rate to be paid by
         MERCK on Net Sales in that country under Section 5.4.1 [**].

5.4.6    COMPETITIVE PRODUCT. In the event a Competitive Product is sold in a
         country, then the royalty rate to be paid by MERCK on Net Sales in that
         country under Section 5.4.1 shall be [**] percent ([**]%) in such
         country during such time that a Competitive Product is sold in such
         country; provided, however, this Section shall not be applicable if the
         royalty rate in such country [**] pursuant to Section 5.4.1.

5.4.7    THIRD PARTY LICENSES. In the event that one or more patent licenses
         from other Third Parties are required by MERCK, its Affiliates and
         sublicensees in order to develop, make, have made, use or sell the
         Licensed Product (hereinafter "Third Party Patent Licenses"), and, in
         the absence of such license, the use by MERCK of the Patent Rights,
         NITROMED Know-How or NITROMED Information and Inventions would infringe
         such Third Party patents, then [**] percent ([**]%) of any
         consideration actually paid under such Third Party Patent Licenses by
         MERCK, its Affiliates or sublicensees, for sale of such Licensed
         Product in a country for such Calendar Quarter shall be creditable
         against the royalty payments due NITROMED by MERCK with respect to the
         sale of such Licensed Products in such country; PROVIDED THAT the
         royalty payment to NITROMED in any Calendar Quarter shall not be
         reduced by more than [**] percent ([**]%) of the monies otherwise owed
         to NITROMED; and any amounts not able to be reduced due to the
         immediately foregoing limitation shall be carried forward to future
         Calendar Quarters for crediting against future royalties in such
         country. Notwithstanding the foregoing, NITROMED shall assume full
         responsibility for any payments to the extent necessary for rights
         under the patents identified in Attachment 5.4.7 and/or bear all costs
         associated with any legal actions to invalidate such patents.

5.5.     REPORTS; PAYMENT OF ROYALTY. During the term of the Agreement following
         the First Commercial Sale of a Licensed Product, MERCK shall furnish to
         NITROMED a quarterly written report for the Calendar Quarter showing
         the sales of all Licensed Products subject to royalty payments sold by
         MERCK, its Affiliates and its sublicensees in the Territory during the
         reporting period and the royalties payable under this Agreement.
         Reports shall be due on the sixtieth (60) day following the close of
         each Calendar Quarter. Royalties shown to have accrued by each royalty
         report shall be due and payable on the date such royalty report is due.
         MERCK shall keep complete and accurate records in sufficient detail to
         enable the royalties payable hereunder to be determined.

5.6.     AUDITS.

(a)      Upon the written request of NITROMED and not more than once in each
         Calendar Year, MERCK shall permit an independent certified public
         accounting firm of nationally

                                       19
<PAGE>

         recognized standing selected by NITROMED and reasonably acceptable to
         MERCK, at NITROMED's expense, to have access during normal business
         hours to such of the records of MERCK as may be reasonably necessary to
         verify the accuracy of the royalty reports hereunder for any year
         ending not more than twenty-four (24) months prior to the date of such
         request. The accounting firm shall disclose to NITROMED only whether
         the royalty reports are correct or incorrect and the specific details
         concerning any discrepancies. No other information shall be provided to
         NITROMED.

(b)      If such accounting firm concludes that additional royalties were owed
         during such period, MERCK shall pay the additional royalties within
         thirty (30) days of the date NITROMED delivers to MERCK such accounting
         firm's written report so concluding. The fees charged by such
         accounting firm shall be paid by NITROMED unless the underpayment
         exceeded five hundred thousand ($500,000) dollars and five percent (5%)
         of the royalty owed by MERCK to NITROMED for such Calendar Year, in
         which case, MERCK shall pay the fees charged by such accounting firm.

(c)      MERCK shall include in each sublicense granted by it pursuant to this
         Agreement a provision requiring the sublicensee to make reports to
         MERCK, to keep and maintain records of sales made pursuant to such
         sublicense and to grant access to such records by NITROMED's
         independent accountant to the same extent required of MERCK under this
         Agreement. Upon the expiration of twenty-four (24) months following the
         end of any year, the calculation of royalties payable with respect to
         such year shall be binding and conclusive upon NITROMED, and MERCK and
         its sublicensees shall be released from any liability or accountability
         with respect to royalties for such year.

(d)      NITROMED shall treat all financial information subject to review under
         this Section 5.6 or under any sublicense agreement in accordance with
         the confidentiality provisions of this Agreement, and shall cause its
         accounting firm to enter into an acceptable confidentiality agreement
         with MERCK obligating it to retain all such financial information in
         confidence pursuant to such confidentiality agreement; provided however
         nothing shall prevent NITROMED from using such financial information in
         any dispute resolution pursuant to Section 9.6.

5.7      PAYMENT EXCHANGE RATE. All payments to be made by MERCK to NITROMED
         under this Agreement shall be made in United States dollars and may be
         paid by check made to the order of NITROMED or bank wire transfer in
         immediately available funds to such bank account in the United States
         designated in writing by NITROMED from time to time. In the case of
         sales outside the United States, the rate of exchange to be used in
         computing the amount of currency equivalent in United States dollars
         due NITROMED shall be made at the rate of exchange utilized by MERCK in
         its worldwide accounting system, prevailing on the third to the last
         business day of the month prior to the month for which Merck records
         such sales.

5.8      INCOME TAX WITHHOLDING. If laws, rules or regulations require
         withholding of income taxes or other taxes imposed upon payments set
         forth in this Article V, MERCK shall make such withholding payments as
         required and subtract such withholding payments from the payments set
         forth in this Article V. MERCK shall submit original receipts or

                                       20
<PAGE>

         other appropriate proof of payment of the withholding taxes to NITROMED
         within a reasonable period of time and which are sufficient to allow
         NITROMED to document such tax withholdings adequately for purposes of
         claiming foreign tax credits and similar benefits.

                                   ARTICLE VI
                  REPRESENTATIONS AND WARRANTIES AND LIABILITY

6.1      REPRESENTATIONS AND WARRANTIES OF NITROMED. NITROMED represents and
         warrants to MERCK that as of the Effective Date:

         (a)      to the best of NITROMED's knowledge, the Patent Rights and
                  NITROMED Know-How exist and are not invalid or unenforceable,
                  in whole or in part;

         (b)      it has the full right, power and authority to enter into this
                  Agreement, to perform the Research Program and to grant the
                  licenses granted under Article III hereof;

         (c)      it has not previously assigned, transferred, conveyed or
                  otherwise encumbered its right, title and interest in Patent
                  Rights or NITROMED Know-How;

         (d)      to the best of NITROMED's knowledge, it is the sole and
                  exclusive owner of the Patent Rights and NITROMED Know-How,
                  all of which are (and shall be, in the case of NITROMED
                  Information and Invention) free and clear of any liens,
                  charges and encumbrances, and no other person, corporate or
                  other private entity, or governmental entity or subdivision
                  thereof, has or shall have any claim of ownership with respect
                  to the Patent Rights and NITROMED Know-How, whatsoever;

         (e)      to the best of NITROMED's knowledge, the exercise of the
                  license granted to MERCK under the Patent Rights and NITROMED
                  Know-How do not infringe any intellectual property rights
                  owned or possessed by any Third Party;

         (f)      there are no claims, judgments or settlements against or owed
                  by NITROMED or pending or threatened claims or litigation
                  relating to the Patent Rights and NITROMED Know-How; and

         (g)      NITROMED has disclosed to MERCK all reasonably relevant
                  information regarding the Patent Rights and NITROMED Know-How
                  licensed under this Agreement, including the existence of any
                  patent opinions obtained by NITROMED related thereto.

6.2      REPRESENTATIONS AND WARRANTIES OF MERCK. MERCK represents and warrants
         to NITROMED that as of the Effective Date:

         (a)      to the best of MERCK's knowledge, the MERCK Know-How does not
                  infringe any intellectual property rights owned or possessed
                  by any Third Party;

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<PAGE>

         (b)      MERCK shall provide all necessary MERCK Know-How, that is in
                  MERCK's possession, to NITROMED to permit NITROMED to perform
                  NITROMED's obligations under the Research Program;

         (c)      it has the full right, power and authority to enter into this
                  Agreement and to fulfill it obligations hereunder; and

         (d)      that all necessary consents, approvals and authorizations of
                  all government authorities and other persons required to be
                  obtained by MERCK in connection with the execution, delivery
                  and performance of this Agreement have been or shall be
                  obtained.

6.3      NO WARRANTIES. EXCEPT AS OTHERWISE EXPRESSLY SET FORTH HEREIN, THE
         PARTIES MAKE NO REPRESENTATIONS AND EXTEND NO WARRANTIES OF ANY KIND,
         EITHER EXPRESS OR IMPLIED, AND PARTICULARLY THAT THE LICENSED
         PRODUCT(S) WILL BE SUCCESSFULLY DEVELOPED HEREUNDER, AND IF LICENSED
         PRODUCT(S) ARE DEVELOPED, WITH RESPECT TO SUCH LICENSED PRODUCT(S), THE
         PARTIES DISCLAIM ALL IMPLIED WARRANTIES OF TITLE, NON-INFRINGEMENT,
         MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

6.4      INDEMNIFICATION. MERCK agrees to defend NITROMED and its Affiliates at
         its cost and expense, and will indemnify and hold NITROMED and its
         Affiliates and their respective directors, officers, employees and
         agents (the "NITROMED Indemnified Parties") harmless from and against
         any losses, costs, damages, fees or expenses arising out of any Third
         Party claim relating to personal injury or death from the development,
         manufacture, use, sale or other disposition of the Licensed Product by
         MERCK and/or its Affiliates, sublicensees or collaborators. In the
         event of any such claim against the NITROMED Indemnified Parties by any
         Third Party, NITROMED shall promptly notify MERCK in writing of the
         claim and MERCK shall manage and control, at its sole expense, the
         defense of the claim and its settlement. The NITROMED Indemnified
         Parties shall cooperate with MERCK and may, at their option and
         expense, be represented in any such action or proceeding. MERCK shall
         not be liable for any litigation costs or expenses incurred by the
         NITROMED Indemnified Parties without MERCK's prior written
         authorization. In addition, MERCK shall not be responsible for the
         indemnification of any NITROMED Indemnified Party arising from any
         negligent or intentional acts by such NITROMED Indemnified Party, or as
         the result of any settlement or compromise by the NITROMED Indemnified
         Parties without MERCK's prior written consent.

6.5      NO CONSEQUENTIAL DAMAGES. UNLESS RESULTING FROM A PARTY'S WILLFUL
         MISCONDUCT, NEITHER PARTY HERETO WILL BE LIABLE FOR SPECIAL,
         INCIDENTAL, CONSEQUENTIAL, EXEMPLARY, PUNITIVE, MULTIPLE OR OTHER
         INDIRECT DAMAGES ARISING OUT OF THIS AGREEMENT OR THE EXERCISE OF ITS
         RIGHTS HEREUNDER, OR FOR LOSS OF PROFITS, LOSS OF DATA OR LOSS OF USE
         DAMAGES ARISING FROM OR RELATING TO ANY BREACH OF THIS AGREEMENT
         WHETHER BASED UPON WARRANTY, CONTRACT, TORT, STRICT LIABILITY OR
         OTHERWISE, REGARDLESS OF

                                       22
<PAGE>

         ANY NOTICE OF SUCH DAMAGES. NOTHING IN THIS SECTION 6.5 IS INTENDED TO
         LIMIT OR RESTRICT THE INDEMNIFICATION RIGHTS OR OBLIGATIONS OF EITHER
         PARTY UNDER THIS AGREEMENT.

                                   ARTICLE VII
                                PATENT PROVISIONS

7.1      FILING, PROSECUTION AND MAINTENANCE OF PATENTS.

         (a)      PATENT RIGHTS. NITROMED shall have the exclusive right and
                  option to file and prosecute any patent applications and
                  maintain any patents covering the Patent Rights licensed to
                  MERCK under this Agreement, upon appropriate consultation with
                  MERCK including an opportunity to review and comment on any
                  papers to be filed in any patent office prior to their
                  submission. NITROMED shall promptly give notice to MERCK of
                  the allowance, grant, lapse, revocation, surrender,
                  invalidation or abandonment of any Patent Rights licensed to
                  MERCK for which NITROMED is responsible for the filing,
                  prosecution and maintenance. If NITROMED declines to file and
                  prosecute any such patent applications or maintain any such
                  patents covering any Patent Rights licensed to MERCK under
                  this Agreement, it shall give MERCK reasonable notice to this
                  effect and thereafter MERCK may, upon written notice to
                  NITROMED, file and prosecute such patent applications and
                  maintain such patents in NITROMED's name.

         (b)      NITROMED INFORMATION AND INVENTIONS. NITROMED shall have the
                  exclusive right and option to file and prosecute any patent
                  applications and maintain any patents covering NITROMED
                  Information and Inventions, upon appropriate consultation with
                  MERCK including an opportunity to review and comment on any
                  papers to be filed in any patent office prior to their
                  submission. If NITROMED declines the option to file and
                  prosecute any such patent applications or maintain any such
                  patents covering any NITROMED Information and Invention, it
                  shall give MERCK reasonable notice to this effect and
                  thereafter MERCK may, upon written notice to NITROMED, file
                  and prosecute such patent applications and maintain such
                  patents in NITROMED's name.

         (c)      JOINT INFORMATION AND INVENTIONS. MERCK shall have the
                  exclusive right and option to file and prosecute any patent
                  applications and to maintain any patents covering Joint
                  Information and Inventions owned jointly by MERCK and
                  NITROMED, upon appropriate consultation with NITROMED
                  including an opportunity to review and comment on any papers
                  to be filed in any patent office prior to their submission. If
                  MERCK declines the option to file and prosecute any such
                  patent applications or maintain any such patents covering any
                  such Joint Information and Inventions, it shall give NITROMED
                  reasonable notice to this effect and thereafter NITROMED may,
                  upon written notice to MERCK, file and prosecute such patent
                  applications and maintain such patents jointly in both
                  Parties' names.

                                       23
<PAGE>

         (d)      MERCK INFORMATION AND INVENTIONS. MERCK shall have the
                  exclusive right and option to file and prosecute any patent
                  applications and to maintain any patents covering MERCK
                  Information and Inventions, at MERCK's expense.

         (e)      EXPENSES. All costs associated with filing, prosecuting and
                  maintaining the COX-2 Compound Specific Patent Rights shall be
                  shared equally by the Parties. All costs associated with
                  filing, prosecuting and maintaining all other NITROMED
                  Information and Inventions shall be borne by NITROMED. All
                  costs associated with the filing, prosecuting and maintaining
                  the Joint Information and Inventions and MERCK Information and
                  Inventions under Sections 7.1(c) and (d) shall be at MERCK's
                  expense. If the initial prosecuting Party declines to file,
                  prosecute and/or maintain any of the Patent Rights and
                  Research Information and Inventions under Sections 7.1 (a)-(c)
                  and the other Party assumes such responsibilities, the initial
                  prosecuting Party shall continue to pay [**] percent ([**]%)
                  of the costs associated with these patents or patent
                  applications; provided however that if the initial prosecuting
                  Party wishes to abandon any such patents or patent
                  applications it shall notify the other Party who shall have
                  the option to continue such patents or patent applications at
                  its own expense and the initial prosecuting Party shall assign
                  it rights to the other Party and the assigned patents or
                  patent applications shall no longer be Patent Rights or
                  Research Information and Inventions. As used herein the term
                  "COX-2 Compound Specific Patent Rights" means (i) those Patent
                  Rights, and (ii) those NITROMED Information and Inventions,
                  whose patents or patent application principally contain claims
                  that relate to COX-2 Compounds, NO-COX-2 Compounds or
                  NO-Enhanced COX-2 Compounds.

7.2      INTERFERENCE, OPPOSITION, REEXAMINATION AND REISSUE.

         (a)      NITROMED shall, within ten (10) days of learning of such
                  event, inform MERCK of any request for, or filing or
                  declaration of, any interference, opposition, or reexamination
                  relating to Patent Rights. MERCK and NITROMED shall thereafter
                  consult and cooperate fully to determine a course of action
                  with respect to any such proceeding. MERCK shall have the
                  right to review and approve any submission to be made in
                  connection with such proceeding.

         (b)      NITROMED shall not initiate any reexamination, opposition,
                  interference or reissue proceeding relating to Patent Rights
                  without the prior written consent to MERCK, which consent
                  shall not be unreasonably withheld.

         (c)      In connection with any interference, opposition, reissue, or
                  reexamination proceeding relating to Patent Rights, MERCK and
                  NITROMED will cooperate fully and will provide each other with
                  any information or assistance that either may reasonably
                  request. NITROMED shall keep MERCK informed of developments in
                  any such action or proceeding, including to the extent
                  permissible by law, consultation and approval of any
                  settlement.

         (d)      The Parties shall equally bear the expense of any
                  interference, opposition, reexamination, or reissue proceeding
                  specified in this Section 7.2 relating to COX-2

                                       24
<PAGE>

                  Compound Specific Patent Rights, including but not limited to
                  any costs incurred by NITROMED in fulfilling its obligations
                  under this Section 7.2. NITROMED shall bear the expense of any
                  interference, opposition, reexamination, or reissue proceeding
                  specified in this Section 7.2 relating to any NitroMed
                  Information and Inventions that do not constitute COX-2
                  Compound Specific Patent Rights, including but not limited to
                  any costs incurred by NITROMED in fulfilling its obligations
                  under this Section 7.2.

7.3      ENFORCEMENT AND DEFENSE.

         (a)      NITROMED shall give MERCK notice of either (i) any
                  infringement of Patent Rights, (ii) any misappropriation or
                  misuse of NITROMED Know-How; or (iii) infringement,
                  misappropriation or misuse of the Research Information and
                  Inventions, that may come to NITROMED's attention. MERCK and
                  NITROMED shall thereafter consult and cooperate fully to
                  determine a course of action, including but not limited to the
                  commencement of legal action by either or both MERCK and
                  NITROMED, to terminate any infringement of Patent Rights,
                  Research Information and Inventions or any misappropriation or
                  misuse of NITROMED Know-How. However, NITROMED, upon notice to
                  MERCK, shall have the first right to initiate and prosecute
                  such legal action (other than for the MERCK Information and
                  Inventions) at its own expense and in the name of NITROMED and
                  MERCK, or to control the defense of any declaratory judgment
                  action relating to Patent Rights, Research Information and
                  Inventions or NITROMED Know-How. NITROMED shall promptly
                  inform MERCK if it elects not to exercise such first right and
                  MERCK shall thereafter have the right to either initiate and
                  prosecute such action or to control the defense of such
                  declaratory judgment action in the name of MERCK and, if
                  necessary, NITROMED and the Parties shall share the expense of
                  such suit equally; provided that MERCK shall pay all costs and
                  shall recoup NITROMED's [**]percent ([**]%) share as a set-off
                  against royalties or milestones until NITROMED's share has
                  been fully paid; provided that the royalty payment to NITROMED
                  in any Calendar Quarter shall not be reduced by more than [**]
                  percent ([**]%) of the monies otherwise owed to NITROMED; and
                  any amounts not able to be reduced due to the immediately
                  foregoing limitation shall be carried forward to future
                  Calendar Quarters for crediting against future royalties in
                  such country. Each Party shall have the right to be
                  represented by counsel of its own choice.

         (b)      For any action to terminate any infringement of Patent Rights
                  or any misappropriation or misuse of NITROMED Know-How, in the
                  event that MERCK is unable to initiate or prosecute such
                  action solely in its own name, NITROMED will join such action
                  voluntarily and will execute and cause its Affiliates to
                  execute all documents necessary for MERCK to initiate
                  litigation to prosecute and maintain such action.

         (c)      Prior to commencing any action pursuant to subsections (a) or
                  (b) above, each Party shall consult with the other Party and
                  shall consider the views of the other Party regarding the
                  advisability of the proposed action. In connection with any
                  action, MERCK and NITROMED will cooperate fully and will
                  provide each other with any

                                       25
<PAGE>

                  information or assistance that either may reasonably request
                  any such action. MERCK shall keep NITROMED informed of
                  developments in any action or proceeding, including the
                  consultation and approval of any settlement negotiations and
                  the terms of any offer related thereto. Neither Party shall
                  enter into any settlement, consent judgment, or other
                  voluntary final disposition without the prior written consent
                  of the other Party.

         (d)      Any recovery obtained by either or both MERCK and NITROMED in
                  connection with or as a result of any action contemplated by
                  this Section 7.3, whether by settlement or otherwise, shall be
                  shared in order as follows:

                  (i)      the Party which initiated and prosecuted the action
                           shall recoup all of its costs and expenses incurred
                           in connection with the action;

                  (ii)     the other Party shall then, to the extent possible,
                           recover its costs and expenses incurred in connection
                           with the action;

                  (iii)    the amount of any recovery remaining from ordinary
                           damages shall then be allocated between the Parties
                           such that MERCK shall receive an amount equal to its
                           lost profits or a reasonable royalty on the
                           infringing sales, or whichever measure of damages the
                           court shall have applied, and that NITROMED shall
                           receive a reasonable approximation of the royalties
                           and other amounts that MERCK would have paid to
                           NITROMED if MERCK had sold the infringing products
                           rather than the infringer, and on a pro rata basis
                           taking into consideration the relative economic
                           losses suffered by each Party; and

                  (iv)     the amount of any recovery remaining from special or
                           punitive damages shall be shared equally by the
                           Parties in any such award.

         (e)      NITROMED shall inform MERCK of any certification regarding any
                  Patent Rights it has received pursuant to either 21 U.S.C.
                  ss.ss.355(b)(2)(A)(iv) or (j)(2)(A)(vii)(IV) or its successor
                  provisions or any similar provisions in a country in the
                  Territory other than the United States and shall provide MERCK
                  with a copy of such certification within five (5) days of
                  receipt. NITROMED's and MERCK's rights with respect to the
                  initiation and prosecution of any legal action as a result of
                  such certification or any recovery obtained as a result of
                  such legal action shall be as defined in Sections 7.3(a)-(d)
                  hereof; provided, however, NITROMED shall exercise its first
                  right to initiate and prosecute any action and shall inform
                  MERCK of such decision within ten (10) days of receipt of the
                  certification, after which time MERCK shall have the right to
                  initiate and prosecute such action.

         (f)      In the event that a Third Party brings an action against
                  NITROMED or MERCK alleging invalidity, unenforceability, or
                  non-infringement of the Patent Rights, the Parties shall
                  cooperate as defined above and shall mutually agree upon an
                  appropriate course of action.

                                       26
<PAGE>

7.4      PATENT TERM RESTORATION. The Parties hereto shall cooperate with each
         other in obtaining patent term restoration or supplemental protection
         certificates or their equivalents in any country in the Territory where
         applicable to Patent Rights. In the event that elections with respect
         to obtaining such patent term restoration are to be made, MERCK shall
         have the right to make a good faith election of the patent to be used.
         In the event MERCK does not promptly make an election of a patent for
         patent term restoration, NITROMED shall have the right to make a good
         faith election of the patent to be used.

                                  ARTICLE VIII
                              TERM AND TERMINATION

8.1      TERM AND EXPIRATION. This Agreement shall be effective as of the
         Effective Date and unless terminated earlier pursuant to Sections 8.2
         or 8.3 below, the term of this Agreement shall continue in effect until
         expiration of all royalty obligations hereunder. Upon expiration of
         this Agreement due to expiration of all royalty obligations hereunder,
         MERCK's licenses pursuant to Section 3.1 shall become non-exclusive,
         fully paid-up, perpetual licenses which shall be limited to the Field.

8.2      TERMINATION BY MERCK. Notwithstanding anything contained herein to the
         contrary, MERCK shall have the right to terminate this Agreement at any
         time in its sole discretion after the Research Program Term, by giving
         ninety (90) days advance written notice to NITROMED. In the event of
         such termination, the rights and obligations hereunder, including any
         payment obligations not due and owing as of the termination date shall
         terminate and NITROMED will grant MERCK a fully paid-up non-exclusive
         license to use the NITROMED Information and Inventions solely for
         internal research purposes.

8.3      TERMINATION.

         8.3.1    TERMINATION FOR CAUSE. This Agreement may be terminated by
                  notice by either Party at any time during the term of this
                  Agreement if the other Party is in breach of its material
                  obligations hereunder by causes and reasons within its control
                  and has not cured such breach within ninety (90) days after
                  written notice requesting cure of the breach (other than for
                  non-payment which must be cured within forty five (45) days);
                  provided, however, in the event of a good faith dispute with
                  respect to the existence of a material breach, the ninety (90)
                  day or forty five (45) day cure period shall be followed until
                  such time as the dispute is resolved pursuant to Section 9.6
                  hereof.

         8.3.2    EFFECT OF TERMINATION FOR CAUSE ON LICENSE. In the event MERCK
                  terminates this Agreement under Section 8.3.1, MERCK's
                  licenses pursuant to Sections 3.1 shall become exclusive,
                  perpetual licenses which are limited to the Field; provided,
                  however, MERCK shall continue to fulfill MERCK's payment
                  and/or royalty obligations as specified herein; provided,
                  further, MERCK may reduce such payment and/or royalty
                  obligations by the amount of monetary damage suffered by MERCK
                  as a direct result of NITROMED's breach of this Agreement and
                  NITROMED shall, within thirty (30) days after such

                                       27
<PAGE>

                  termination return or cause to be returned to MERCK all
                  Licensed Products, NO-Enhanced COX-2 Compounds, MERCK Know-How
                  or other substances or compositions delivered or provided by
                  MERCK, as well as any other material provided by MERCK in any
                  medium. In the event that NITROMED terminates this Agreement
                  under Section 8.3.1, MERCK's licenses pursuant to Sections 3.1
                  shall terminate as of such termination date and MERCK shall,
                  within thirty (30) days after such termination, return or
                  cause to be returned to NITROMED all Licensed Products,
                  NO-Enhanced COX-2 Compounds, Know-How or other substances or
                  compositions delivered or provided by NITROMED, as well as any
                  other material provided by NITROMED in any medium.

8.4      EFFECT OF TERMINATION. Expiration or termination of the Agreement shall
         not relieve the Parties of any obligation accruing prior to such
         expiration or termination and nothing in this Agreement shall be
         construed to release either Party from any obligations that matured
         prior to the effective date of expiration or termination, and the
         provisions of Sections 2.6.1, 2.6.2, 3.3, 6.3, 6.4, 6.5, 8.3.2,
         Articles IV, V, VII and IX shall survive the expiration or termination
         of the Agreement. Any expiration or early termination of this Agreement
         shall be without prejudice to the rights of either Party against the
         other accrued or accruing under this Agreement prior to termination,
         including the obligation to pay royalties for Licensed Product(s) sold
         prior to such termination.

                                   ARTICLE IX
                                  MISCELLANEOUS

9.1.     FORCE MAJEURE. Neither Party shall be held liable or responsible to the
         other Party nor be deemed to have defaulted under or breached the
         Agreement for failure or delay in fulfilling or performing any term of
         the Agreement when such failure or delay is caused by or results from
         causes beyond the reasonable control of the affected Party including,
         but not limited to, fire, floods, embargoes, war, acts of war (whether
         war be declared or not), insurrections, riots, civil commotions,
         strikes, lockouts or other labor disturbances, acts of God or acts,
         omissions or delays in acting by any governmental authority or the
         other Party. The affected Party shall notify the other Party of such
         force majeure circumstances as soon as reasonably practical.

9.2.     ASSIGNMENT. The Agreement may not be assigned or otherwise transferred,
         nor, except as expressly provided hereunder, may any right or
         obligations hereunder be assigned or transferred, by either Party
         without the consent of the other Party; PROVIDED, HOWEVER, that either
         Party may, without such consent, assign the Agreement and its rights
         and obligations hereunder to an Affiliate or in connection with the
         transfer or sale of all or substantially all of its assets related to
         the Licensed Products or the business, or in the event of its merger or
         consolidation or change in control or similar transaction. Any
         permitted assignee shall assume all obligations of its assignor under
         the Agreement.

9.3.     SEVERABILITY. In the event any one or more of the provisions contained
         in this Agreement should be held invalid, illegal or unenforceable in
         any respect, the validity, legality and enforceability of the remaining
         provisions contained herein shall not in any way be

                                       28
<PAGE>

         affected or impaired thereby, unless the absence of the invalidated
         provision(s) adversely affect the substantive rights of the Parties.
         The Parties shall in such an instance use their best efforts to replace
         the invalid, illegal or unenforceable provision(s) with valid, legal
         and enforceable provision(s) which, insofar as practical, implement the
         purposes of this Agreement.

9.4.     NOTICES. All notices or other communications which are required or
         permitted hereunder shall be in writing and sufficient if delivered
         personally, sent by telecopier (and promptly confirmed by personal
         delivery, registered or certified mail or overnight courier), sent by
         nationally-recognized overnight courier or sent by registered or
         certified mail, postage prepaid, return receipt requested, addressed as
         follows:

                  if to NITROMED, to:       NitroMed, Inc.
                                            12 Oak Park Drive
                                            Bedford, MA 01730
                                            Attention: Chief Executive Officer
                                            Telephone: (781) 275-9700
                                            Facsimile No.: (781) 275-2282

                  with a copy to:           Hale and Dorr LLP
                                            60 State Street
                                            Boston, MA 02109
                                            Attention: Steven D. Singer, Esq.
                                            Telephone: (617) 526-6410
                                            Facsimile No.: (617) 526-5000

                  if to MERCK, to:          Merck Frosst Canada & Co.
                                            16711 Trans Canada Hwy.
                                            Kirkland, Quebec
                                            Canada
                                            H9H 3L1
                                            Attention: President
                                            Telephone: (514) 428-2638
                                            Facsimile: (514) 428-2662

                  with a copies to:         Merck Frosst Canada & Co.
                                            16711 Trans Canada Hwy.
                                            Kirkland, Quebec
                                            Canada
                                            H9H 3L1
                                            Attention: Director, Legal Affairs
                                            Telephone: (514) 428-8577
                                            Facsimile: (514) 428-4925

                  and

                                       29
<PAGE>

                                            Merck & Co., Inc.
                                            One Merck Drive
                                            P.O. Box 100
                                            Whitehouse Station, NJ  08889-0100
                                            Attention: Corporate Secretary
                                            Telephone: (908) 423-1000
                                            Facsimile: (908) 735-1224

         or to such other address as the Party to whom notice is to be given may
         have furnished to the other Party in writing in accordance herewith.
         Any such communication shall be deemed to have been given when
         delivered if personally delivered or sent by telecopier on a business
         day, on the business day after dispatch if sent by
         nationally-recognized overnight courier and on the third business day
         following the date of mailing if sent by mail.

9.5.     APPLICABLE LAW. The Agreement shall be governed by and construed in
         accordance with the laws of the State of New Jersey and the United
         States without reference to any rules of conflict of laws or renvoi.

9.6.     DISPUTE RESOLUTION. The Parties shall negotiate in good faith and use
         reasonable efforts to settle any dispute, controversy or claim arising
         from or related to this Agreement or the breach thereof. If the Parties
         do not fully settle, and a Party wishes to pursue the matter, each such
         dispute, controversy or claim that is not an "Excluded Claim" shall be
         finally resolved by binding arbitration in accordance with the
         Commercial Arbitration Rules and Supplementary Procedures for Large
         Complex Disputes of the American Arbitration Association ("AAA"), and
         judgment on the arbitration award may be entered in any court having
         jurisdiction thereof. The arbitration shall be conducted by a panel of
         three persons experienced in the pharmaceutical business: within 30
         days after initiation of arbitration, each Party shall select one
         person to act as arbitrator and the two party-selected arbitrators
         shall select a third arbitrator within 30 days of their appointment. If
         the arbitrators selected by the Parties are unable or fail to agree
         upon the third arbitrator, the third arbitrator shall be appointed by
         the AAA. The place of arbitration shall be New York, New York. Either
         Party may apply to the arbitrators for interim injunctive relief until
         the arbitration award is rendered or the controversy is otherwise
         resolved. Either Party also may, without waiving any remedy under this
         Agreement, seek from any court having jurisdiction any injunctive or
         provisional relief necessary to protect the rights or property of that
         Party pending the arbitration award. The arbitrators shall have no
         authority to award punitive or any other type of damages not measured
         by a Party's compensatory damages. Each Party shall bear its own costs
         and expenses and attorneys' fees and an equal share of the arbitrators'
         and any administrative fees of arbitration. Except to the extent
         necessary to confirm an award or as may be required by law, neither a
         Party nor an arbitrator may disclose the existence, content, or results
         of an arbitration without the prior written consent of both Parties. In
         no event shall an arbitration be initiated after the date when
         commencement of a legal or equitable proceeding based on the dispute,
         controversy or claim would be barred by the applicable New York statute
         of limitations. As used in this Section 9.6, the term "Excluded Claim"
         shall mean a dispute, controversy or claim that concerns (a) the
         validity or infringement of a patent, trademark

                                       30
<PAGE>

         or copyright; or (b) any antitrust, anti-monopoly or competition law or
         regulation, whether or not statutory.

9.7.     ENTIRE AGREEMENT. The Agreement contains the entire understanding of
         the Parties with respect to the subject matter hereof. All express or
         implied agreements and understandings, either oral or written,
         heretofore made are expressly merged in and made a part of the
         Agreement. The Agreement may be amended, or any term hereof modified,
         only by a written instrument duly executed by both Parties hereto.

9.8.     HEADINGS. The captions to the several Articles and Sections hereof are
         not a part of the Agreement, but are merely guides or labels to assist
         in locating and reading the several Articles and Sections hereof.

9.9.     INDEPENDENT CONTRACTORS. It is expressly agreed that NITROMED and MERCK
         shall be independent contractors and that the relationship between the
         two Parties shall not constitute a partnership, joint venture or
         agency. Neither NITROMED nor MERCK shall have the authority to make any
         statements, representations or commitments of any kind, or to take any
         action, which shall be binding on the other, without the prior consent
         of the other Party.

9.10.    WAIVER. The waiver by either Party hereto of any right hereunder or the
         failure to perform or of a breach by the other Party shall not be
         deemed a waiver of any other right hereunder or of any other breach or
         failure by said other Party whether of a similar nature or otherwise.

9.11.    COUNTERPARTS. The Agreement may be executed in two or more
         counterparts, each of which shall be deemed an original, but all of
         which together shall constitute one and the same instrument.

9.12.    WAIVER OF RULE OF CONSTRUCTION. Each Party has had the opportunity to
         consult with counsel in connection with the review, drafting and
         negotiation of this Agreement. Accordingly, the rule of construction
         that any ambiguity in this Agreement shall be construed against the
         drafting Party shall not apply.

9.13     ENGLISH LANGUAGE. The parties hereto confirm that it is their wish that
         this Agreement as well as all other documents relating hereto,
         including notices, have been and shall be drawn up in the English
         language only. Les parties aux presentes confirment leur volonte que
         cette convention de meme que tous les documents, y compris tout avis,
         s'y rattachant, soient rediges en langue anglaise seulement.

                                       31
<PAGE>

         IN WITNESS WHEREOF, the Parties have executed this Agreement as of the
date first set forth above.

        MERCK FROSST CANADA & CO.                      NITROMED, INC.

By: /s/ JUDY C. LEWENT                         By: /s/ MICHAEL D. LOBERG
    ----------------------------                  -----------------------------
        Judy C. Lewent                                 Michael D. Loberg

Title: Vice President                          Title: CEO

Date: 12/12/02                                 Date: 12/11/02
      --------                                       --------

Merck & Co., Inc. a corporation organized under the laws of the State of New
Jersey hereby guarantees the performance of all the foregoing obligations of its
subsidiary, Merck Frosst Canada & Co.

         MERCK & CO., INC.

By: /s/ JUDY C. LEWENT
    ----------------------------
        Judy C. Lewent

Title: Executive Vice President and Chief
Financial Officer

Date: 12/12/02
      --------

                                       32
<PAGE>

                                 ATTACHMENT 1.36
                                  PATENT RIGHTS
<TABLE>
<CAPTION>
----------------------------------------------------------------------------------------------------------------------
  SERIAL/PATENT     DATE FILED                       TITLE                                     STATUS
      NUMBER
----------------------------------------------------------------------------------------------------------------------
<S>               <C>                            <C>                                <C>
     [**]              [**]                          [**]                                       [**]
----------------------------------------------------------------------------------------------------------------------
     [**]              [**]                          [**]                                       [**]
----------------------------------------------------------------------------------------------------------------------
     [**]              [**]                          [**]                                       [**]
----------------------------------------------------------------------------------------------------------------------
     [**]              [**]                          [**]                                       [**]
----------------------------------------------------------------------------------------------------------------------
     [**]              [**]                          [**]                                       [**]
----------------------------------------------------------------------------------------------------------------------
     [**]              [**]                          [**]                                       [**]
----------------------------------------------------------------------------------------------------------------------
     [**]              [**]                          [**]                                       [**]
----------------------------------------------------------------------------------------------------------------------
     [**]              [**]                          [**]                                       [**]
----------------------------------------------------------------------------------------------------------------------
     [**]              [**]                          [**]                                       [**]
----------------------------------------------------------------------------------------------------------------------
     [**]              [**]                          [**]                                       [**]
----------------------------------------------------------------------------------------------------------------------
     [**]              [**]                          [**]                                       [**]
----------------------------------------------------------------------------------------------------------------------
     [**]              [**]                          [**]                                       [**]
----------------------------------------------------------------------------------------------------------------------
     [**]              [**]                          [**]                                       [**]
----------------------------------------------------------------------------------------------------------------------
     [**]              [**]                          [**]                                       [**]
----------------------------------------------------------------------------------------------------------------------
</TABLE>

<PAGE>

<TABLE>
<CAPTION>
----------------------------------------------------------------------------------------------------------------------
  SERIAL/PATENT     DATE FILED                       TITLE                                     STATUS
      NUMBER
----------------------------------------------------------------------------------------------------------------------
<S>               <C>                            <C>                                <C>
     [**]              [**]                          [**]                                       [**]
----------------------------------------------------------------------------------------------------------------------
     [**]              [**]                          [**]                                       [**]
----------------------------------------------------------------------------------------------------------------------
     [**]              [**]                          [**]                                       [**]
----------------------------------------------------------------------------------------------------------------------
     [**]              [**]                          [**]                                       [**]
----------------------------------------------------------------------------------------------------------------------
     [**]              [**]                          [**]                                       [**]
----------------------------------------------------------------------------------------------------------------------
</TABLE>

<PAGE>

                                 ATTACHMENT 2.1
                                RESEARCH PROGRAM

Merck is interested in determining the viability of developing therapies which
will [**]. [**]. The proposed collaboration would [**]. Merck would bring to the
collaboration [**] NitroMed would bring its [**]

In general, Merck will perform the following components of the workplan:

1. [**]
2. [**]
3. [**]
4. [**]
5. [**]

In general, NitroMed will perform the following components of the workplan:

1. [**]
2. [**]
3. [**]

               A. COMPOUND DISCOVERY AND INITIAL CHARACTERIZATION

Merck will [**]. Initially, these efforts will [**] as outlined in the Merck
NitroMed agreement. [**] to support this effort are as follows:

1. [**]
2. [**]
3. [**]
4. [**]
5. [**]
6. [**]

SPECIFIC ASSAY DETAILS:

[**] (MERCK)
[**]
[**] (MERCK)
[**]

From time to time, the collaboration may merit NitroMed performing the two
above mentioned assays. In these cases, the specific assay details are:

[**] (NITROMED)
[**] (NITROMED)
[**]

                                 B. [**] (MERCK)

Merck considers it essential to [**]. This is particularly important in the
[**], Merck plans to [**]. Merck would like to [**], Merck hopes to [**]
described above. From this information, [**].

                                C. [**] INTEREST

[**], performed predominantly by NitroMed.  These include the following:

Merck
1. [**]
2. [**]
3. [**]
4. [**]
5. [**]

NitroMed
1. [**]
2. [**]
3. [**]
4. [**]
5. [**]
6. [**]

<PAGE>

SPECIFIC ASSAY DETAILS:

[**] (MERCK)
Compounds are [**].  The use of [**].
[**].
[**] (MERCK)
[**] for the study of [**].  To study the [**].[**] according to the
manufacturer's instructions.
[**]) according to the manufacturer's instructions.

[**] (MERCK)
[**].

[**] (NITROMED)
[**]
[**] (NITROMED)
[**]
[**].

[**] (NITROMED)
[**].

[**] (NITROMED)
[**].

[**] (NITROMED)
[**].[**]
[**] (NITROMED)
[**] (NITROMED)
[**].

[**] (NITROMED)
[**].

                           D. NITROMED FTE ASSIGNMENTS

In the first year of the agreement, [**]FTEs will be assigned by NitroMed and
supported by Merck. Their approximate allocation to the above mentioned
experiments will be as follows:

[**]:
         A total of [**]FTE's dedicated to evaluating selected compounds from
Merck in the following models

                                        2
<PAGE>

1. [**]
2. [**]
3. [**]
4. [**]
5. [**]
6. [**]
7. [**]

[**]:
         A total of [**] FTE's dedicated to evaluating selected compounds from
Merck in the following models:

1. [**]
2. [**]
3. [**]

                                        3
<PAGE>

                                ATTACHMENT 5.4.7
                                  [**] PATENTS

<TABLE>
<CAPTION>
========================== =========== ================================================ =====================
         PATENT/           DATE FILED                       TITLE                              STATUS
   APPLICATION NUMBER
-------------------------- ----------- ------------------------------------------------ =====================
<S>                      <C>                             <C>                               <C>
          [**]                [**]                          [**]                                [**]
-------------------------- ----------- ------------------------------------------------ ---------------------
          [**]                [**]                          [**]                                [**]
-------------------------- ----------- ------------------------------------------------ ---------------------
          [**]                [**]                          [**]                                [**]
-------------------------- ----------- ------------------------------------------------ ---------------------
          [**]                [**]                          [**]                                [**]
-------------------------- ----------- ------------------------------------------------ ---------------------
          [**]                [**]                          [**]                                [**]
-------------------------- ----------- ------------------------------------------------ ---------------------
          [**]                [**]                          [**]                                [**]
-------------------------- ----------- ------------------------------------------------ ---------------------
          [**]                [**]                          [**]                                [**]
-------------------------- ----------- ------------------------------------------------ ---------------------
          [**]                [**]                          [**]                                [**]
-------------------------- ----------- ------------------------------------------------ ---------------------
          [**]                [**]                          [**]                                [**]
-------------------------- ----------- ------------------------------------------------ ---------------------
          [**]                [**]                          [**]                                [**]
========================== =========== ================================================ =====================
</TABLE>

and any extensions (including Supplementary Protection Certificates),
divisionals, reissues and continuations of any of the above patents or
applications for patent, including any foreign counterparts derived therefrom,
equivalent thereto or claiming priority thereof, as well as any European
national patents entered from patents granted in the European Patent Office and
National Phase filings entered from applications filed under the Patent
Cooperation Treaty.

                                       4<Page>

                                                              EXHIBIT NO. 10.6

-------------------------------------------------------------------------------
                         Confidential Materials Omitted
                          and filed separately with the
                       Securities and Exchange Commission.
                          Asterisks denote ommissions.
-------------------------------------------------------------------------------

                         RESEARCH AND LICENSE AGREEMENT

         This Agreement is effective August 1, 1992 ("the EFFECTIVE DATE") by
and between The Brigham and Women's Hospital, Inc. ("HOSPITAL"), having an
address at 75 Francis Street, Boston, Massachusetts 02115, and NitroMed, Inc., a
Delaware Corporation having offices at c/o Healthcare Investment Corp., 379
Thornall Street, Edison, New Jersey 08837 ("NITROMED").

         WHEREAS, NITROMED desires to fund certain work to be performed at
HOSPITAL in exchange for exclusive licenses in and to certain Patents,
technology, materials and information; and

         WHEREAS, HOSPITAL desires to receive such funding and is willing to
grant the exclusive licenses desired by NITROMED.

         NOW THEREFORE in consideration of the mutual promises and other good
and valuable consideration, the parties agree as follows:

SECTION 1 - DEFINITIONS.

         The terms used in this Agreement have the following meaning:

1.1 The term "AFFILIATE" as applied to NITROMED shall mean any company or other
legal entity other than NITROMED in whatever country organized, controlling,
controlled by or under common control with NITROMED. The term "control" means
possession, of the power to direct or cause the direction of the management and
policies whether through the ownership of voting securities, by contract or
otherwise.

                                       1
<Page>

     1.2 The term "FIRST COMMERCIAL SALE" shall mean in each country the first
sale of any PRODUCT by NITROMED, its AFFILIATES or SUBLICENSEES, following
approval of its marketing by the appropriate governmental agency for the country
in which the sale is to be made and when governmental approval is not required,
the first sale in that country.

     1.3 The term "RESEARCH INVENTION" shall mean any process, use, article of
manufacture, composition of matter conceived or first actually or constructively
reduced to practice in the performance of SPONSORED RESEARCH and/or any other
research funded in whole or in part by NITROMED pursuant to this Agreement
solely or jointly by at least one INVESTIGATOR, whether or not in the FIELD OF
RESEARCH.

     1.4 The term "BACKGROUND INVENTION" shall mean any process, use, article of
manufacture, composition of matter conceived or reduced to practice by PRINCIPAL
INVESTIGATOR (alone or with others) prior to the EFFECTIVE DATE, which is within
the FIELD OF RESEARCH.

     1.5 "INVENTION" shall mean individually and collectively RESEARCH INVENTION
and BACKGROUND INVENTION.

     1.6 The term "INVESTIGATOR" means PRINCIPAL INVESTIGATOR, any other member
of the HOSPITAL Professional Staff, graduate student, undergraduate student, or
employee of HOSPITAL who shall perform SPONSORED RESEARCH.

     1.7 The term "SUBLICENSEE" shall mean any non-AFFILIATE third party
licensed by NITROMED to make, have made, import, use or sell any PRODUCT or use
any PROCESS under PATENT RIGHTS.

                                       2
<Page>

     1.8 The term "BACKGROUND MATERIAL" shall mean any material or substance
which relates to the FIELD OF RESEARCH and is in the possession of HOSPITAL
through the PRINCIPAL INVESTIGATOR or the PRINCIPAL INVESTIGATOR on the
EFFECTIVE DATE.

     1.9 The term "RESEARCH MATERIAL" shall mean any material or substance which
is discovered, produced or derived by an INVESTIGATOR in the performance of
SPONSORED RESEARCH and/or any other research funded in whole or in part by
NITROMED pursuant to this Agreement.

     1.10 "HOSPITAL MATERIAL" shall mean individually and collectively
BACKGROUND MATERIAL and RESEARCH MATERIAL.

     1.11 "NET SALES PRICE" means the total amount received by NITROMED or
its AFFILIATES or SUBLICENSEE from sale of PRODUCT, less transportation
charges and insurance, sales taxes, use taxes, excise taxes, value added
taxes, customs duties or other imposts, normal and customary quantity and
cash discounts, and allowances and credit on account of rejection or return
of PRODUCT.

     PRODUCT shall be considered "sold" when billed out or invoiced.

     1.12 The term "BACKGROUND PATENT RIGHT(s)" shall mean any United States
patent application, including any division, continuation, or
continuation-in-part thereof and any foreign patent application or equivalent
corresponding thereto and any Letters Patent or the equivalent thereof issuing
thereon or reissue or extension thereof, insofar as it contains one or more
claims to a BACKGROUND INVENTION, BACKGROUND INFORMATION, or BACKGROUND
MATERIAL. The BACKGROUND PATENT RIGHTS are tabulated in Appendix B.

                                       3
<Page>

     1.13 The term "RESEARCH PATENT RIGHT(S)" shall mean any United States
patent application, including any division, continuation, or
continuation-in-part thereof and any foreign patent application or equivalent
corresponding thereto and any Letters Patent or the equivalent thereof issuing
thereon or reissue or extension thereof, insofar as it contains one or more
claims to a RESEARCH INVENTION, RESEARCH INFORMATION, or RESEARCH MATERIAL.

     1.14 "PATENT RIGHT(S)" shall mean individually and collectively BACKGROUND
PATENT RIGHTS and RESEARCH PATENT RIGHTS.

     1.15 The term "PRINCIPAL INVESTIGATOR" shall mean either or both Dr.
Joseph Loscalzo and Dr. Jonathan Stamler.

     1.16 The term "PRODUCT" shall mean any article, composition, apparatus,
substance, chemical, material, method or service which is an HOSPITAL
MATERIAL, or which is, incorporates or utilizes an INVENTION and/or
INFORMATION, or the manufacture, import, sale or use of which is covered by
PATENT RIGHTS.

     1.17 The term "PROCESS" shall mean any process or method for the
production, manufacture or use of any PRODUCT.

     1.18 The term "BACKGROUND INFORMATION" shall mean any data, formulas,
process information or other information pertaining to the FIELD OF RESEARCH
known to HOSPITAL through PRINCIPAL INVESTIGATOR or the PRINCIPAL
INVESTIGATOR on the EFFECTIVE DATE.

     1.19 "RESEARCH INFORMATION" shall mean any data, formulas, process
information or other information produced by an INVESTIGATOR in the performance
of SPONSORED RESEARCH and/or any other research funded in whole or in part by
NITROMED pursuant to this Agreement.

                                       4
<Page>

     1.20 "INFORMATION" shall mean individually and collectively RESEARCH
INFORMATION and BACKGROUND INFORMATION.

     1.21 The term "RESEARCH PROPOSAL" shall mean the written description of
SPONSORED RESEARCH attached hereto as Appendix A, including a budget that
details the equipment, materials and the personnel to be provided by use of
the funds to be supplied by NITROMED to support the research described in
such proposal or any other written description of research attached hereto by
Agreement of the parties pursuant to Paragraph 2.2.

     1.22 The term "SPONSORED RESEARCH" shall mean described in the RESEARCH
PROPOSAL.

     1.23 VALID CLAIM shall mean (i) a claim of a pending patent Application
which has been pending for no more than seven (7) years from the filing date
of the original subject matter covered by the claim or, (ii) a claim of an
issued patent which has not lapsed or become abandoned or been declared
invalid or unenforceable by a court of competent jurisdiction or an
administrative agency from which no appeal can be or is taken.

     1.24 "FIELD OF RESEARCH" means (i) nitric oxide compounds, nitrosothiol
compounds, nitroso protein compounds and nitrosylated compounds, and/or
compounds related to the above and/or (ii) uses for such compounds including but
not limited to diagnostic, therapeutic and prophylactic and/or (iii) agonists
and antagonists thereof.

     1.25 "AGREEMENT YEAR" shall mean the twelve month period beginning on
the EFFECTIVE DATE, and each subsequent twelve (12) month period thereafter.

     1.26 "LICENSED TERRITORY" shall mean all countries of the world.

                                       5
<Page>

     1.27 The use herein of the plural shall include the singular, and the use
of the masculine shall include the feminine.

SECTION 2 - FUNDING.

     2.1 (A) In consideration of the undertaking of SPONSORED RESEARCH by
HOSPITAL, during the period in which SPONSORED RESEARCH is being conducted:

     (i)  subject to Paragraph 13.1, NITROMED shall make annual research grants
          to HOSPITAL for the support of SPONSORED RESEARCH as follows:

<Table>
<Caption>
                      AGREEMENT               RESEARCH
                        YEAR               GRANT PER YEAR
                        ----               --------------
<S>                <C>                  <C>
                         1                    $[**]
                                               ======
                         2                    $[**]
                                               ======
                   3 through 10               $[**]
                                               ======
</Table>

     (ii) each annual grant shall be paid in four equal quarterly payments. The
          first payment shall be paid within thirty (30) days of the execution
          of this Agreement by NITROMED;

     (iii) the funding shall include direct and/or indirect expenses as set
           forth in the RESEARCH PROPOSAL;

     (B)  at least sixty (60) days prior to the end of an AGREEMENT YEAR,
          HOSPITAL shall submit to NITROMED for its approval a plan and budget
          for use of the funding for the following AGREEMENT YEAR, which
          approval shall not be unreasonably denied. NITROMED shall provide such
          approval or disapproval within thirty (30) days from receipt of
          HOSPITAL's plan and budget. Such approved-plan and budget shall be
          attached and made a part hereof. The approved plan and budget for the
          first AGREEMENT YEAR is attached hereto as Appendix C.

                                       6
<Page>

     (C)  within sixty (60) days after the end of an AGREEMENT YEAR, HOSPITAL
          shall provide NITROMED with an accounting of the expenditure of
          research funds for such AGREEMENT YEAR in accordance with HOSPITAL
          standard procedures for such accounting.

     (D)  NITROMED shall pay the costs of leasing those items of equipment
          listed or to be listed in Appendix D which are selected by PRINCIPAL
          INVESTIGATOR and leased by HOSPITAL and which have an aggregate fair
          market value not exceeding $[**] in the first AGREEMENT YEAR, and
          $[**] in each of the subsequent AGREEMENT YEARS, all of such
          equipment shall be owned by HOSPITAL upon completion of the term of
          the relevant lease. All such leases shall have terms at least as long
          as the initial term of the RESEARCH PROPOSAL for the research in
          which the equipment is to be used. NITROMED shall pay HOSPITAL the
          amounts owed under each lease at least thirty (30) days prior to the
          date on which payments are due to the lessor.

     2.2 During the period during which NITROMED is funding SPONSORED RESEARCH
under this Agreement, either party may propose in writing additional research
not previously described in the RESEARCH PROPOSAL appended hereto as Appendix A.
Each such proposal shall include a description of the additional research
proposed and a budget of the costs to be funded by NITROMED and a schedule of
payment of such costs. When and if such proposal is accepted by HOSPITAL and
NITROMED, it shall be appended hereto as a RESEARCH PROPOSAL and shall be
subject to the terms and conditions of this Agreement unless otherwise
specified, and the SPONSORED RESEARCH described therein shall commence and
additional budgeted amounts shall be paid as set forth in the proposal or as
otherwise agreed by the parties in writing. When and if such proposal is
rejected by NITROMED, subject to Paragraph 2.3 below, HOSPITAL may seek funding
from another commercial sponsor.

                                       7
<Page>

     2.3 During the period during which NITROMED is funding SPONSORED RESEARCH
under this Agreement, an INVESTIGATOR may not seek funding from another
commercial sponsor for an additional research proposal in the FIELD of RESEARCH
until such proposal has been submitted to NITROMED in accordance with the
foregoing Paragraph 2.2 and the parties have not agreed to append such proposal
hereto as a RESEARCH PROPOSAL. In the event of such failure to agree, an
INVESTIGATOR shall be free to seek and accept funding from another commercial
sponsor for such research proposal, provided, that the subject.

     In the event an INVESTIGATOR is permitted to seek funding from another
commercial sponsor under this Paragraph 2.3, INVESTIGATOR shall discuss with
NITROMED potential commercial sponsors from whom INVESTIGATOR intends to seek
such funding.

     2.4 The Hospital shall have the right to choose one or more outside
observers to make an independent scientific review of the research conducted
hereunder by the Hospital and to report to the Hospital on an annual basis. The
costs and expenses of the review, not to exceed $[**] per year, shall be paid
by NITROMED. It is expected that the annual cost will generally be no more than
$[**] per year.

SECTION 3 - WORK OF HOSPITAL.

     3.1 During the thirty (30) days next following the EFFECTIVE DATE,
HOSPITAL, through the PRINCIPAL INVESTIGATOR, shall disclose to NITROMED such
BACKGROUND INFORMATION and BACKGROUND MATERIAL which shall be known to HOSPITAL
and PRINCIPAL INVESTIGATOR on the EFFECTIVE DATE.

                                       8
<Page>

     3.2 Beginning on the EFFECTIVE DATE and thereafter unless sooner
terminated, HOSPITAL shall:

     (a)  through the PRINCIPAL INVESTIGATOR conduct SPONSORED RESEARCH, and
          apply the funds paid by NITROMED pursuant to Paragraph 2.1 or 2.2 to
          support the expenses of SPONSORED RESEARCH in accordance with the
          RESEARCH PROPOSAL and shall use reasonable efforts and diligence
          consistent with HOSPITAL's professional standards to achieve the goals
          set forth in such RESEARCH PROPOSAL.

     (b)  promptly and systematically disclose to NITROMED, INFORMATION,
          INVENTIONS and HOSPITAL MATERIAL, and NITROMED shall be entitled to
          use such INFORMATION, INVENTIONS and HOSPITAL MATERIAL as provided
          herein.

     (c)  for the purpose of facilitating disclosure to NITROMED of RESEARCH
          INFORMATION, INVENTIONS, and HOSPITAL MATERIAL, permit duly authorized
          employees of or representatives of NITROMED to visit the PRINCIPAL
          INVESTIGATOR'S laboratories at HOSPITAL or other HOSPITAL facilities
          where SPONSORED RESEARCH is conducted at reasonable times and with
          reasonable notice;

     (d)  promptly advise NITROMED of any INVENTION and adequate advance notice
          of the intent to file, filing, allowance and issuance of any PATENT
          RIGHT; and

     (e)  at NITROMED's request provide NITROMED with HOSPITAL MATERIALS.

                                       9
<Page>

     3.3 HOSPITAL shall, on a continuing basis, advise NITROMED of the results
of the SPONSORED RESEARCH and at least once every six (6) months provide
NITROMED with written progress reports concerning the SPONSORED RESEARCH. A
final written report setting forth in detail the results achieved under and
pursuant to the SPONSORED RESEARCH shall be submitted by HOSPITAL to NITROMED
within ninety (90) days of termination of the SPONSORED RESEARCH. Such final
report shall include: (i) a complete summary of the research carried out; (ii) a
scientific assessment by the PRINCIPAL INVESTIGATOR of the SPONSORED RESEARCH;
and (iii) detailed experimental protocols of the assays performed in the course
of the SPONSORED RESEARCH.

SECTION 4 - HOSPITAL MATERIALS.

     4.1 (a) During the period in which the SPONSORED RESEARCH is being
conducted, and in which NITROMED holds a license, HOSPITAL and INVESTIGATORS
shall not, without NITROMED's prior written approval, distribute or knowingly
allow HOSPITAL MATERIALS to be distributed to for-profit entities or persons
known to be employed thereby or consulting or performing research therefor other
than under a license permitted under this Agreement.

     (a) HOSPITAL and PRINCIPAL INVESTIGATOR shall have the right to transfer
HOSPITAL MATERIALS to not-for-profit entities or persons known to be affiliated
therewith provided that such entities or persons sign the Material Transfer
Agreement attached hereto as Appendix E or any other Agreement consented to by
the parties.

     (b) Prior to any such distribution of any such HOSPITAL MATERIAL, HOSPITAL
and NITROMED shall use reasonable efforts to consider the patentability of such
HOSPITAL MATERIALS and cooperate to file, where appropriate, PATENT RIGHTS
protecting such HOSPITAL MATERIALS prior to their distribution.

                                       10
<Page>

     4.2 Notwithstanding anything else to the contrary, HOSPITAL and
INVESTIGATOR agree not to publish or disclose to third parties the identity of
new compounds, or new methods of synthesis, conceived or developed as part of
the performance of the SPONSORED RESEARCH without supplying NITROMED with a copy
of the material to be disclosed or published to third parties at least sixty
(60) days prior notice of such publication or disclosure so that NITROMED may
evaluate such material to determine whether the material contains patentable
subject matter relating to an INVENTION on which a patent application should be
filed or contains NITROMED Confidential Information as defined in Paragraph 6.1.
NITROMED shall review the material within fifteen (15) days of submission to
NITROMED. At NITROMED's request, HOSPITAL initially will delay submission of the
manuscript for an additional thirty (30) days in order to enable the preparation
and filing of a patent application on any such patentable subject matter and
will cooperate with NITROMED in deleting from any such manuscript NITROMED
Confidential Information the inclusion of which would contravene Paragraphs 6.1
and 6.3 hereof. Notwithstanding anything to the contrary HOSPITAL will not be
required to withhold submission of such material for a period which is more than
ninety (90) days after NITROMED is first provided with the material to be
disclosed or published.

SECTION 5 - GRANTS.

     5.1 (a) HOSPITAL hereby grants to NITROMED and NITROMED hereby accepts from
HOSPITAL a sole and exclusive royalty bearing right and license for the LICENSED
TERRITORY under PATENT RIGHTS and INVENTION to make, have made, use and sell or
have sold on its behalf PRODUCT or LICENSED PROCESS, including the right to
sublicense third parties. NITROMED shall have the right to extend such license
to its AFFILIATES.

                                       11
<Page>

     (b) In the event that PATENT RIGHTS and INVENTIONS are co-owned by HOSPITAL
and a third party, the license granted in Paragraph 5.1(a) shall only apply to
HOSPITAL'S interest in such PATENT RIGHTS and INVENTIONS. For PATENT RIGHTS or
INVENTIONS owned jointly by HOSPITAL and at least one third party, HOSPITAL
shall pursuant to Paragraph 7.1(a) of this Agreement attempt to obtain an
agreement granting on behalf of all of the owners thereof a sole and exclusive
right and license to NITROMED. If terms agreeable to all of the parties
(including such third party assignees) can not be reached or, at NITROMED's
request, HOSPITAL will be relieved from its obligations under Paragraph 7.1(a)
of this Agreement and only HOSPITAL'S interest in such PATENT RIGHTS and
INVENTION shall be licensed to NITROMED under Paragraph 5.1(a) of this
Agreement.

     5.2 NITROMED agrees to forward to HOSPITAL a copy of any and all fully
executed sublicense agreements, and further agrees to forward to HOSPITAL
annually a copy of such reports received by NITROMED from its SUBLICENSEES
during the preceding twelve (12) month period under the sublicensees as shall be
pertinent to a royalty accounting to HOSPITAL under said sublicense agreements.

     5.3 The above licenses to sell any PRODUCT includes the right of NITROMED,
its AFFILIATES, and SUBLICENSEES to grant to the purchaser thereof the right to
use and/or resell such purchased PRODUCT.

     5.4 All licenses pursuant to Paragraphs 5.2 and 5.3 above to PATENT RIGHTS
conceived or first actually reduced to practice during the course of research
funded by a U.S. federal agency are subject to the rights, conditions and
limitations imposed by U.S. law. The words "sole and exclusive license" as used
herein shall mean sole and exclusive except for the royalty free non-exclusive
license granted to the U.S. government by HOSPITAL pursuant to 35 USC Section
202(c)(4) for any PATENT RIGHTS claiming any INVENTION subject to 35 USC Section
201 and any other federal laws and applicable regulations.

                                       12
<Page>

     5.5 HOSPITAL agrees not to enter into an agreement with a third party to
acquire materials for use in SPONSORED RESEARCH under terms that will prevent
HOSPITAL from granting NITROMED exclusive rights to PATENT RIGHTS and INVENTION.

     5.6 (a) Taking into account the complexity, and stage of development of the
PRODUCT and the science related thereto, NITROMED shall select and use
reasonable efforts and diligence under the circumstances to research, develop
and then commercialize a selected PRODUCT. The efforts of a SUBLICENSEE and/or
an AFFILIATE and the SPONSORED RESEARCH shall be considered as efforts of
NITROMED.

         (b) In the event that HOSPITAL reasonably believes that NITROMED is not
making reasonable efforts under the circumstances to research, develop and then
commercialize a selected PRODUCT by NITROMED pursuant to Paragraph 5.6(a) then
HOSPITAL shall provide written notice to NITROMED which specifies HOSPITAL's
basis for such belief and what additional efforts HOSPITAL believes should be
made by NITROMED. Upon receipt of such written notice, HOSPITAL and NITROMED
shall enter into good faith negotiations in order to reach mutual agreement as
to what efforts by NITROMED shall satisfy the requirements of this Paragraph
5.6, and if such mutual agreement is not reached within [**] days after
receipt of such written notice, then the parties agree to submit to
arbitration pursuant to Paragraph 14.2 to determine the efforts which should
be exerted by NITROMED. Thereafter, NITROMED shall exert the efforts
determined by the parties or in such arbitration.

                                       13
<Page>

     (c) If NITROMED fails to exert the efforts determined by the parties or in
such arbitration, HOSPITAL's sole and exclusive remedy for NITROMED's failure to
meet such efforts is for the licenses granted hereunder to be converted from an
exclusive right and license to a non-exclusive license, provided that NITROMED
has initiated and continues to expend a minimum of [**] dollars ($[**]) per
year on the research and development of a selected PRODUCT until the FIRST
COMMERCIAL SALE of a PRODUCT. If NITROMED does not initiate and continue the
research and development of a selected PRODUCT as specified in this Paragraph
5.6(c), HOSPITAL's sole and exclusive remedy is for the such non-exclusive
license to be terminated.

     5.7 HOSPITAL acknowledges that NITROMED is in the business of developing,
manufacturing and selling of medical processes and products and nothing in this
Agreement shall be construed as restricting such business or imposing on
NITROMED the duty to market, and/or sell and exploit PRODUCT for which royalties
are due hereunder to the exclusion of or in preference to any other product or
process.

     5.8 Subject to Section 5.6, NITROMED shall have sole discretion for making
all decisions relating to the commercialization and marketing of PRODUCT, and
will bear the cost of preparing such PRODUCT for market and for obtaining
governmental approvals where required.

     5.9 Within sixty (60) days after the end of each calendar year, NITROMED
shall report in writing to HOSPITAL on the progress of its efforts under
Paragraph 5.6.

SECTION 6 - CONFIDENTIALITY.

     6.1 During the term of this Agreement, it is contemplated that each party
will disclose to the other proprietary and confidential technology, inventions,
technical information, biological materials and the like which are owned or
controlled by the party providing such information or which that party is
obligated to maintain in confidence and which is designated by the party
providing such information as confidential ("Confidential Information"). Each
party shall have the right to refuse to accept the other party's Confidential
Information. Each party agrees to retain such Confidential Information in
confidence and not to disclose any such Confidential Information to a third
party without the prior written consent of the party providing such information
and to use such Confidential Information only for the purposes of this
Agreement.

                                       14
<Page>

     6.2 The obligations of confidentiality will not apply to Confidential
Information which:

     (i)  was known to the receiving party or generally known to the public
          prior to its disclosure hereunder; or

     (ii) subsequently becomes known to the public by some means other than a
          breach of this Agreement, including publication and/or laying open to
          inspection of any patent applications or patents;

     (iii) is subsequently disclosed to the receiving party by a third party
          having a lawful right to make such disclosure;

     (iv) is disclosed to obtain regulatory approval for PRODUCT, provided that
          the disclosing party takes all reasonable steps to restrict and
          maintain the confidentiality of the disclosure ;

     (v)  is required by law or BONA FIDE legal process to be disclosed,
          provided that the disclosing party takes all reasonable steps to
          restrict and maintain confidentiality of such disclosure and provides
          reasonable notice to the non-disclosing party; or

    (vi)  is approved for release by the parties.

                                       15
<Page>

SECTION 7 - PATENTS.

     7.1 (a) Each INVESTIGATOR who during the course of SPONSORED RESEARCH shall
make an INVENTION, solely or jointly, ("HOSPITAL INVENTOR") shall promptly
report such INVENTION to HOSPITAL. Each HOSPITAL INVENTOR shall assign all of
his rights, title and interest in an INVENTION and PATENT RIGHTS relating
thereto to HOSPITAL. Each employee of NITROMED who makes an INVENTION jointly
with an INVESTIGATOR, shall report such INVENTION to NITROMED and shall assign
all his rights, title and interest in such INVENTION and PATENT RIGHTS relating
thereto to NITROMED. INVENTIONS made jointly by one or more INVESTIGATORS and
one or more NITROMED employees and PATENT RIGHTS relating thereto shall be
jointly owned by HOSPITAL and NITROMED. HOSPITAL and NITROMED agree that for
each PATENT RIGHT jointly owned by HOSPITAL and NITROMED, NITROMED and HOSPITAL
each own a one-half undivided interest in such PATENT RIGHT in each country in
which it is filed and HOSPITAL's interest therein is subject to the rights
granted to NITROMED under this Agreement.

     In the event any INVENTION results from collaboration with personnel who
is not affiliated with either HOSPITAL or NITROMED ("Unaffiliated
Collaborator(s)"), HOSPITAL shall attempt to obtain the relevant rights from
the institution of such Unaffiliated Collaborators and include same in the
aforesaid rights granted to NITROMED under Section 5 of this Agreement.

     (b) HOSPITAL shall promptly advise NITROMED in writing of each INVENTION
disclosed to HOSPITAL. Representatives of HOSPITAL and NITROMED shall then
discuss whether a patent application or applications pertaining to such
INVENTION should be filed and in which countries. The titles, serial numbers and
other identifying data of patent applications claiming an INVENTION filed after
the EFFECTIVE DATE by mutual agreement of HOSPITAL and NITROMED shall be listed
in Appendix B and shall become PATENT RIGHTS.

                                       16
<Page>

         NITROMED shall file, prosecute and maintain patent applications and
patents directed to INVENTIONS through patent counsel selected by NITROMED who
shall consult with and keep HOSPITAL advised with respect thereto.

         After the EFFECTIVE DATE of this Agreement, NITROMED shall bear the
cost and expense for the filing, prosecution and maintenance of PATENT RIGHTS in
the United States, European Patent Office, Canada, Japan and any other foreign
countries designated by NITROMED.

     7.2 With respect to any PATENT RIGHTS, each patent application, office
action, response to office action, request for terminal disclaimer, and request
for reissue or reexamination of any patent issuing from such application shall
be provided to HOSPITAL sufficiently prior to the filing of such application,
response or request to allow for review and comment by HOSPITAL. HOSPITAL shall
have the right to take any action that in its judgment is necessary to preserve
such PATENT RIGHTS.

     7.3 [**] percent ([**]%) of the amount paid by NITROMED pursuant to
this Section 7 expended by NITROMED to secure or maintain any PATENT RIGHTS
shall be fully creditable against royalties due under Section 8, but no royalty
payment, after taking into consideration any deduction pursuant to Section 8.2,
shall be reduced under this Paragraph 7.3 by more than [**]%.

                                       17
<Page>

SECTION 8 - ROYALTIES AND EQUITY.

     8.1 (A) On all sales of PRODUCTS anywhere in the world by NITROMED, its
AFFILIATES or SUBLICENSEE, following the FIRST COMMERCIAL SALE in such country
by NITROMED its AFFILIATES or SUBLICENSEES, NITROMED shall pay HOSPITAL
royalties in accordance with the following schedule, such undertaking and
schedule having been agreed to for the purpose of reflecting and advancing the
mutual convenience of the parties. For each PRODUCT sold or distributed by
NITROMED or its AFFILIATES and SUBLICENSEES NITROMED shall pay to HOSPITAL one
of the following:

     (1)  (i) [**] percent ([**]%) of the NET SALES PRICE of PRODUCTS (other
          than PRODUCTS which are a diagnostic product or service) sold or
          distributed by NITROMED or its AFFILIATES in a country and (ii) [**]
          percent ([**]%) of the NET SALES PRICE of PRODUCT (other than PRODUCTS
          which are a diagnostic product or service) sold or distributed by
          SUBLICENSEES in a country (iii) [**] percent ([**]%) of the NET SALES
          PRICE of PRODUCTS which are diagnostic products or diagnostic services
          sold or distributed by NITROMED or its AFFILIATES in a country and
          (iv) [**] ([**]%) of the NET SALES PRICE of PRODUCT which are
          diagnostic products or diagnostic services sold or distributed by
          SUBLICENSEES in a country so long as in each case the PRODUCT, its
          manufacture, use or sale in the country in question shall be subject
          to a VALID CLAIM of any PATENT RIGHT which is licensed exclusively to
          NITROMED In such country, or

     (2)  (i) [**] percent ([**]%) of the NET SALES PRICE of PRODUCTS (other
          than PRODUCTS which are diagnostic products or diagnostic services)
          sold or distributed by NITROMED or its AFFILIATES in a country and
          (ii) [**]percent ([**]%) of the NET SALES PRICE of PRODUCT (other
          than PRODUCTS which are diagnostic products or diagnostic services)
          sold or distributed by SUBLICENSEES in a country (iii) [**] percent
          ([**]%) of the NET SALES PRICE of PRODUCTS which are diagnostic
          products or diagnostic services sold or distributed by NITROMED or its
          AFFILIATES and (iv) [**] percent ([**]%) of the NET SALES PRICE
          of PRODUCT which are diagnostic products or diagnostic services sold
          or distributed by SUBLICENSEES in a country, whenever, in each case,
          the PRODUCT, its manufacture, use or sale shall be subject to a VALID
          CLAIM of only such PATENT RIGHTS which are licensed non-exclusively to
          NITROMED in the country in question (the term non-exclusive license
          includes a license in which HOSPITAL co-owns the applicable PATENT
          RIGHTS with a third party(ies) and NITROMED does not receive an
          exclusive license under this Agreement from all of the owners), or

                                       18
<Page>

     (3)  (a) For each PRODUCT sold by NITROMED in which a competing product
          employing similar technology is not available, (i) [**] percent
          ([**]%) of the NET SALES PRICE of PRODUCTS sold or distributed by
          NITROMED or its AFFILIATES and (ii) [**] percent ([**]%) of the NET
          SALES PRICE of PRODUCT sold or distributed by SUBLICENSEES (1) for
          ten (10) years next following the FIRST COMMERCIAL SALE of any
          PRODUCT whose manufacture, use or sale shall employ or incorporate
          any HOSPITAL MATERIAL where such HOSPITAL MATERIALS are not subject
          to one or more VALID CLAIMS of any PATENT RIGHT licensed to NITROMED
          in such country or (2) for the ten (10) years next following the FIRST
          COMMERCIAL SALE of any PRODUCT whose manufacture, use or sale shall
          employ as a significant part thereof INFORMATION which is not subject
          to any VALID CLAIM of a PATENT RIGHT licensed to NITROMED in such
          country;

     (B) In the event that a PRODUCT includes both component(s) covered by a
VALID CLAIM of a PATENT RIGHT ("Patented Component(s)") and a component which is
diagnostically useable or therapeutically active alone or in a combination which
does not require the Patented Component and such component is not covered by a
VALID CLAIM of a PATENT RIGHT ("Unpatented Component(s)") (such PRODUCT being a
"Combined Product"), then NET SALES PRICE shall be the amount which is normally
received by NITROMED or its AFFILIATES from a sale of the Patented Component(s)
in an arm's length transaction with an unaffiliated third party. If the Patented
Component(s) are not sold separately, then NET SALES PRICE upon which a royalty
is paid shall be the NET SALES PRICE of the Combined Product multiplied by a
fraction, the numerator of which is the cost for producing the Patented
Components and the denominator of which is the cost for producing the Combined
Product.

     8.2 (a) In the event that royalties are to be paid by NITROMED to a party
who is not an AFFILIATE of NITROMED for PRODUCT for which royalties are also due
to HOSPITAL pursuant to Paragraph 8.1 ("Other Royalties"), then the royalties to
be paid to HOSPITAL by NITROMED pursuant to Paragraph 8.1 shall be reduced by
[**] of the amount of such Other Royalties, but in no event shall any
royalties under Paragraph 8.1 be reduced by more than [**] percent ([**]%).

     (b) In addition to Paragraph 8.2(a), in the event that the royalty paid to
HOSPITAL is a significant factor in the return realized by NITROMED so as to
diminish NITROMED's capability to respond to competitive pressures in the
market, HOSPITAL agrees to consider a reasonable reduction in the royalty paid
to HOSPITAL as to each such PRODUCT for the period during which such market
condition exists. Factors determining the size of the reduction will include
profit margin on PRODUCT and on analogous products, prices of competitive
products, and NITROMED's expenditures in PRODUCT development.

                                       19
<Page>

     8.3 NITROMED shall keep, and shall cause each of its AFFILIATES and
SUBLICENSEES to keep, full and accurate books of account containing all
particulars that may be necessary for the purpose of calculating all royalties
payable to HOSPITAL. Such books of account shall be kept at their principal
place of business and, with all necessary supporting data shall, for the three
(3) years next following the end of the calendar year to which each shall
pertain be open for inspection by HOSPITAL or its designee upon reasonable
notice during normal business hours at HOSPITAL's expense for the sole purpose
of verifying royalty statements or compliance with this Agreement, but in no
event more than once in each calendar year. All information and data offered
shall be used only for the purpose of verifying royalties and shall be treated
as NITROMED Confidential Information subject to the obligations of this
Agreement. In the event that such inspection shall indicate that in any calendar
year that the royalties which should have been paid by NITROMED are at least
five percent (5%) greater than those which were actually paid by NITROMED, then
NITROMED shall pay the cost of such inspection.

     8.4 With each semi-annual payment, NITROMED shall deliver to HOSPITAL a
full and accurate accounting to include at least the following information:

     (a)  Quantity of each PRODUCT subject to royalty sold (by country) by
          NITROMED, and its AFFILIATES;

     (b)  Total receipts for each PRODUCT subject to royalty (by country);

     (c)  Total royalties payable to HOSPITAL;

                                       20
<Page>

     (d)  Royalties received from SUBLICENSEES.

     8.5 In each year the amount of royalty due shall be calculated
semi-annually as of June 30 and December 31 (each as being the last day of an
"ACCOUNTING PERIOD") and shall be paid semi-annually within the sixty days next
following such date, every such payment shall be supported by the accounting
prescribed in Paragraph 8.4 and shall be made in United States currency.
Whenever for the purpose of calculating royalties conversion from any foreign
currency shall be required, such conversion shall be at the rate of exchange
thereafter published in the Wall Street Journal for the business day closest to
the applicable ACCOUNTING PERIOD, as the case may be.

     8.6 If the transfer of or the conversion into United States Dollar
Equivalent of any remittance due hereunder is not lawful or possible in any
country, such remittance shall be made by the deposit thereof in the currency of
the country to the credit and account of HOSPITAL or its nominee in any
commercial bank or trust company located in that country, prompt notice of which
shall be given to HOSPITAL. HOSPITAL shall be advised in writing in advance by
NITROMED and provide to NITROMED a nominee, if so desired.

     8.7 Any tax required to be withheld by NITROMED under the laws of any
foreign country for the account of HOSPITAL, shall be promptly paid by NITROMED
for and on behalf of HOSPITAL to the appropriate governmental authority, and
NITROMED shall use its best efforts to furnish HOSPITAL with proof of payment of
such tax. Any such tax actually paid on HOSPITAL's behalf shall be deducted from
royalty payments due HOSPITAL.

     8.8 Only one royalty shall be due and payable for the manufacture, use and
sale of a PRODUCT irrespective of the number of patents or claims thereof which
cover the manufacture, use and sale of such PRODUCT.

                                       21
<Page>

     8.9 NITROMED shall sell to HOSPITAL common shares of NITROMED in accordance
with a Restricted Stock Purchase Agreement which incorporates the following
terms.

     (a) Upon each issuance of stock by NITROMED, up until and including
issuances pursuant to which the aggregate gross proceeds, from the
capitalization of NITROMED, (other than proceeds from sales to HOSPITAL) shall
equal $3,500,000.00, HOSPITAL shall have the option to purchase a number of
shares of common stock of NITROMED as may be required in order that HOSPITAL'S
pro rata share of the equity of NITROMED on a fully diluted converted basis
immediately after the exercise of such option shall equal fifteen percent (15%).
The price per share is $.01 per share. In the event that the Research and
License Agreement by and between NITROMED and HOSPITAL is terminated for any
reason whatsoever, prior to the noted anniversaries, NITROMED shall have the
right to repurchase from HOSPITAL at a price of $.01 per share the following
percentage of the common shares of stock purchased pursuant to this paragraph.

                           First Anniversary                80%

                           Second Anniversary               40%

                           Third Anniversary                20%

     (b) Prior to an IPO, in any venture capital round of financing, HOSPITAL
has the right to purchase a number of shares offered in such round at the per
share price of such round to maintain the HOSPITAL's percent ownership interest
in NITROMED which exists prior thereto under the same terms provided to
participating venture capital investors.

     (c) Prior to an IPO, HOSPITAL can not sell its purchased shares to a third
party without first offering such shares to NITROMED on terms proposed by
HOSPITAL. If NITROMED elects not to purchase, for a period of six months after
such election by NITROMED, HOSPITAL can sell such shares to a third party on
terms no more favorable than those offered NITROMED. NITROMED has the right to
assign its right as set forth in this subparagraph 8.9(c) to any one or more of
its shareholders.

                                       22
<Page>

     (d) HOSPITAL is hereby granted "piggy-back" registration rights subject to
underwriter cut-back, on a pro-rata basis with other selling shareholders under
"piggy-back" rights. NITROMED will provide and pay for counsel for HOSPITAL for
such registration, which counsel shall be the same as the counsel for other
sellers in such round. The "piggy back" rights of this Paragraph, 8.9(d) shall
also be applicable to demand registrations.

     (e) HOSPITAL agrees to be bound by any "lock-up" requirements of an
underwriter, provided that they are no more stringent then those imposed on the
venture capital shareholders.

SECTION 9 - INFRINGEMENT AND NONASSERTION.

     9.1 (a) If any of the PATENT RIGHTS under which NITROMED is the licensee is
infringed by a third party, NITROMED shall have the right and option but not the
obligation to bring an action for infringement, at its sole expense, against
such third party in the name of HOSPITAL and/or in the name of NITROMED, and to
join HOSPITAL as a party plaintiff if required. NITROMED shall promptly notify
HOSPITAL of any such infringement and shall keep HOSPITAL informed as to the
prosecution of any action for such infringement. No settlement, consent judgment
or other voluntary final disposition of the suit which adversely affects PATENT
RIGHTS may be entered into without the consent of HOSPITAL, which consent shall
not unreasonably be withheld.

     (b) In the event that NITROMED shall undertake the enforcement and/or
defense of the PATENT RIGHTS by litigation, NITROMED may withhold up to fifty
percent (50%) of the royalties otherwise thereafter due HOSPITAL hereunder and
apply the same toward reimbursement of its expenses, including reasonable
attorneys' fees, in connection therewith. Any recovery of damages by NITROMED
for any such suit shall be applied first in satisfaction of any unreimbursed
expenses and legal fees of NITROMED relating to the suit, and next toward
reimbursement of HOSPITAL for any royalties withheld and applied pursuant to
this Section 9. The balance remaining from any such recovery shall be divided
between NITROMED and HOSPITAL, as follows (i) for that portion, if any, based on
lost profits, HOSPITAL shall recover the royalty HOSPITAL "would have received
under this Agreement if such sales had been made by NITROMED; and (ii) for any
other recovery, HOSPITAL shall receive thirty percent (30%) of the remaining
amount.

                                       23
<Page>

     9.2 In the event that NITROMED elects not to pursue an action for
infringement, upon written notice to HOSPITAL by NITROMED that an unlicensed
third party is an infringer of a VALID CLAIM of PATENT RIGHTS licensed to
NITROMED, HOSPITAL shall have the right and option, but not the obligation at
its cost and expense to initiate infringement litigation and to retain any
recovered damages.

     9.3 In the event that litigation against NITROMED is initiated by a
third-party charging NITROMED with infringement of a patent of the third party
as a result of the manufacture, use or sale by NITROMED of PRODUCT covered by
PATENT RIGHTS, NITROMED shall promptly notify HOSPITAL in writing thereof.
NITROMED's costs as to any such defense shall be creditable against any and all
payments due and payable to HOSPITAL under Paragraph 8.1 of this Agreement but
no royalty payment after taking into consideration any such credit under this
Paragraph 9.3 shall be reduced by more than [**]%.

                                       24
<Page>

     9.4 In the event of a judgment in any suit in which a court of competent
jurisdiction rules that the manufacture, use or sale by NITROMED of PRODUCT
covered by a PATENT RIGHT has infringed on a third-party's patent requiring
NITROMED to pay damages or a royalty to said third party, or in the event of a
settlement of such suit requiring damages or royalty payments to be made,
payments due to HOSPITAL under Paragraph 8.1 of this Agreement arising from the
applicable PRODUCT shall be correspondingly reduced by the amounts due under the
requirement of such judgment or under the terms of such settlement. In no case,
however, shall the royalty payment after taking into consideration any such
reduction under this Paragraph 9.4 be reduced by more than [**]%.

     9.5 In any infringement suit either party may institute to enforce the
PATENT RIGHTS pursuant to this Agreement, the other party hereto shall, at the
request 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. All
reasonable out-of-pocket costs of HOSPITAL incurred in connection with rendering
cooperation requested by NITROMED shall be paid by NITROMED.

SECTION 10 - WARRANTIES.

     10.1 Each of HOSPITAL and NITROMED warrants and represents to the other
that it has the full right and authority to enter into this Agreement, and that
it is not aware of any impediment which would inhibit its ability to perform the
terms and conditions imposed on it by this Agreement.

     10.2 HOSPITAL warrants and represents that the named inventors have
assigned the PATENT RIGHTS tabulated in Appendix B to HOSPITAL, that it has not
licensed or assigned any right or interest in or to INVENTIONS and PATENT RIGHTS
to any third party; it has the right to grant the rights granted hereunder; that
the granting of such rights does not require the consent of a third party; that
there are and will be no outstanding agreements, assignments or encumbrances
inconsistent with the provisions of this Agreement, and that all INVESTIGATORS
performing SPONSORED RESEARCH will be obligated to assign to HOSPITAL, in
accordance with the Patent Policy of HOSPITAL, the ownership of INVENTIONS and
corresponding PATENT RIGHTS developed during SPONSORED RESEARCH.

                                       25
<Page>

     10.3 HOSPITAL covenants, warrants and represents that no other patents or
patent applications in the FIELD of RESEARCH naming the PRINCIPAL INVESTIGATORS
exists other than the PATENT RIGHTS tabulated in Appendix B.

     10.4 HOSPITAL covenants, warrants, represents that (i) HOSPITAL has not
received any information with respect to any challenge by another as to the
validity of the BACKGROUND PATENT RIGHTS tabulated in Appendix B and (ii) the
HOSPITAL has not received any information that any of these BACKGROUND PATENT
RIGHTS is involved in an interference action.

SECTION 11 - INDEMNIFICATION.

     11.1 (a) Each party shall notify the other of any claim, lawsuit or other
proceeding related to PRODUCT. Subject to the preceding sentence, NITROMED shall
indemnify, defend and hold harmless HOSPITAL and its trustees, officers, medical
and professional staff, employees and agents and their respective successors,
heirs and assigns (the "Indemnitees"), against any liability, damage, loss or
expense (including 'reasonable attorneys' fees and expenses of litigation)
incurred by or imposed upon the Indemnitees or any one of them in connection
with: (i) claims, suits, actions, demands or judgments arising out of any theory
of product liability (including, but not limited to, actions in the form of
tort, warranty or strict liability) concerning any product, process or service
relating to, or developed pursuant to this Agreement, or (ii) any third party
claims, suits, actions, demands or judgments arising out of any activities to be
carried out by Indemnitees pursuant to this Agreement.

                                       26
<Page>

     (b) NITROMED's indemnification under (a) shall not apply to any liability,
damage, loss or expense to the extent that it is directly attributable to the
negligent activities or intentional misconduct of the Indemnitees.

     (c) NITROMED agrees at its own expense, to provide attorneys reasonably
acceptable to the HOSPITAL to defend against any actions brought or filed
against any party indemnified hereunder with respect to the subject of indemnity
contained herein, whether or not such actions are rightfully brought.

     (d) HOSPITAL shall notify NITROMED promptly of any claim or threatened
claim under this Paragraph 11.1 and shall fully cooperate with all reasonable
requests of NITROMED with respect thereto.

     (e) This Paragraph 11.1 shall survive expiration or termination of this
agreement.

     11.2 (a) At such time as any PRODUCT or PROCESS relating to, or developed
pursuant to, this Agreement is being commercially distributed or sold (other
than for the purpose of obtaining regulatory approvals) by NITROMED or by a
licensee, AFFILIATE or agent of NITROMED, NITROMED shall, at its sole cost and
expense, procure and maintain comprehensive general liability insurance in
amounts not less than two million dollars ($2,000,000) per accident and two
million dollars ($2,000,000) annual aggregate and naming the Indemnities as
additional insureds. Such comprehensive general liability insurance shall
provide (i) product liability coverage and (ii) broad form contractual liability
coverage for NITROMED's indemnification under Paragraph 11.1 of this Agreement.
If NITROMED elects to self-insure all or part of the limits described above
(including deductibles or retentions which are in excess of $250,000 annual
aggregate) such self-insurance program must be acceptable to the HOSPITAL and
the Risk Management Foundation of the Harvard Medical Institutions, Inc. The
minimum amounts of insurance coverage required under this Paragraph 11.2 shall
not be construed to create a limit of NITROMED's liability with respect to its
indemnification under Paragraph 11.2 of this Agreement. At such time NITROMED
can request that HOSPITAL ascertain whether Risk Management Foundation has in
effect Uniform Indemnification and Insurance Provisions more favorable than
those of this Agreement, in which event NITROMED and HOSPITAL shall amend this
Agreement to include such more favorable insurance provisions.

                                       27
<Page>

     (b) NITROMED shall provide HOSPITAL with written evidence of such insurance
upon request of HOSPITAL. NITROMED shall provide HOSPITAL with written notice at
least fifteen (15) days prior to the cancellation, non-renewal or material
change in such insurance.

     (c) NITROMED shall maintain such comprehensive general liability insurance
during (i) the period that any PRODUCT or PROCESS relating to, or developed
pursuant to this Agreement is being commercially distributed to sold (other than
that for the purpose of obtaining regulatory approvals) by NITROMED or by a
licensee, AFFILIATE or agent of NITROMED and (ii) a reasonable period after the
period referred to in (c)(i) above, which in no event shall be less than fifteen
(15) years. The obligations of (c)(ii) above can be satisfied by the purchase of
insurance by NITROMED or third party which covers claims made during such period
of (c)(ii) above for PRODUCT or PROCESS commercially distributed or sold by
NITROMED during the period referred in (c)(i) above.

     (d) This Paragraph 11.2 shall survive expiration or termination of this
Agreement.

SECTION 12 - ASSIGNMENT; SUCCESSORS.

     12.1 This Agreement shall not be assignable by either of the parties
without the prior written consent of the other party (which consent shall not be
unreasonably withheld), except that NITROMED without the consent of HOSPITAL may
assign this Agreement to an AFFILIATE or to a successor in interest of all or
substantially all of the portion of the business to which this Agreement relates
and HOSPITAL without the consent of NITROMED may assign this Agreement to THE
BRIGHAM MEDICAL CENTER, INC. or any wholly owned subsidiary thereof.

     12.2 Subject to the limitations on assignment herein, this Agreement shall
be binding upon and inure to the benefit of said successors in interest and
assigns of NITROMED and HOSPITAL. Any such successor or assignee of a party's
interest shall expressly assume in writing the performance of all the terms and
conditions of this Agreement to be performed by said party and such Assignment
shall not relieve the Assignor of any of its obligations under this Agreement.

SECTION 13 - TERMINATION.

     13.1 Except as otherwise specifically provided herein and unless sooner
terminated pursuant to Paragraph 13.2 or 13.3 of this Agreement, this Agreement
and the licenses and rights granted thereunder shall remain in full force and
effect until the expiration of the last to expire PATENT RIGHT, at which time
NITROMED shall have a fully paid-up license.

                                       28
<Page>

     13.2 Except as qualified by Paragraph 13.7, NITROMED shall have the right
to terminate this Agreement or any or all licenses under one or more PATENT
RIGHTS in one or more countries upon sixty (60) days prior written notice.

     13.3 Upon material breach of any material provisions of this Agreement by
either party to this Agreement, in the event the breach is not cured within
sixty (60) days after written notice to the breaching party by the other party,
in addition to any other remedy it may have, the other party at its sole option
may terminate this Agreement, provided that such other party is not then in
breach of this Agreement.

     13.4 Upon any termination of this Agreement NITROMED shall be entitled to
finish any work-in-progress which is completed within six (6) months of
termination of this Agreement and to sell any completed inventory of a PRODUCT
covered by this Agreement which remains on hand as of the date of the
termination, so long as NITROMED pays to HOSPITAL the royalties applicable to
said subsequent sales in accordance with the same terms and conditions as set
forth in this Agreement.

     13.5 In the event that this Agreement is terminated any SUBLICENSEE shall
have the right to become a direct license of HOSPITAL under PATENT RIGHTS and
INVENTION, to the extent such SUBLICENSEE was previously licensed by NITROMED,
provided that such SUBLICENSEE by written notice to HOSPITAL accepts the
licensing term and conditions of this Agreement within thirty (30) days after
such SUBLICENSEE receives notice that this Agreement has been terminated. Upon
HOSPITAL'S receipt of such notice from SUBLICENSEE, SUBLICENSEE shall be
automatically licensed under the licensing terms and conditions of this
Agreement.

                                       29
<Page>

     13.6 The obligations of Section 6 shall survive any termination of this
Agreement. Further, the obligations of Section 11 shall perpetually survive any
termination of this Agreement.

     13.7 NITROMED may terminate funding of SPONSORED RESEARCH under Paragraph
2.1(A) and lease payments under Paragraph 2.1(D) under this Agreement on the
twenty-fourth (24th) month from the EFFECTIVE DATE of this Agreement, or any day
thereafter by giving HOSPITAL six (6) months prior written notice of its
election to terminate. If such funding is so terminated, NITROMED shall pay
HOSPITAL any reasonable costs and expenses which HOSPITAL has committed to pay
directly related to performance of the SPONSORED RESEARCH which cannot be
eliminated or reduced.

     13.8 In the event PRINCIPAL INVESTIGATOR is no longer available or able to
continue direction of SPONSORED RESEARCH, HOSPITAL shall promptly notify
NITROMED and may nominate a replacement; if HOSPITAL does not nominate a
replacement within thirty (30) days or if that replacement is unsatisfactory to
NITROMED, NITROMED may immediately terminate funding of SPONSORED RESEARCH. If
such funding is so terminated, NITROMED shall pay HOSPITAL any reasonable costs
and expenses which HOSPITAL has committed to pay directly related to performance
of the SPONSORED RESEARCH which cannot be eliminated or reduced.

     13.9 Upon termination of this Agreement for any reason, nothing herein
shall be construed to release either party from any obligation that matured
prior to the effective date of such termination.

                                       30
<Page>

SECTION 14 - GENERAL PROVISIONS.

     14.1 The relationship between HOSPITAL and NITROMED is that of independent
contractors. HOSPITAL and NITROMED are not joint venturers, partners, principal
and agent, master and servant, employer or employee, and have no relationship
other than as independent contracting parties. HOSPITAL shall have no power to
bind or obligate NITROMED in any manner. Likewise, NITROMED shall have no power
to bind or obligate HOSPITAL in any manner.

     14.2 Any matter or disagreement under Paragraph 2.3 or 5.6 which this
Agreement specifically specifies is to be resolved by arbitration shall be
submitted to a mutually selected single arbitrator to so decide any such matter
or disagreement. The arbitrator shall conduct the arbitration in accordance with
the Rules of the American Arbitration Association, unless the parties agree
otherwise. If the parties are unable to mutually select an arbitrator, the
arbitrator shall be selected in accordance with the procedures of the American
Arbitration Association. The decision and award rendered by the arbitrator shall
be final and binding. Judgment upon the award may be entered in any court having
jurisdiction thereof. Any arbitration pursuant to this section shall be held in
Boston, MA, or such other place as may be mutually agreed upon in writing by the
parties.

     14.3 This Agreement sets forth the entire agreement and understanding
between the parties as to the subject matter thereof and supersedes all prior
agreements in this respect. There shall be no amendments or modifications to
this Agreement, except by a written document which is signed by both parties.

     14.4 This Agreement shall be construed and enforced in accordance with the
laws of the Commonwealth of Massachusetts without reference to its choice of law
principles.

                                       31
<Page>

     14.5 The headings in this Agreement have been inserted for the convenience
of reference only and are not intended to limit or expand on the meaning of the
language contained in the particular article or section.

     14.6 Any delay in enforcing a party's rights under this Agreement or any
waiver as to a particular default or other matter shall not constitute a waiver
of a party's right to the future enforcement of its rights under this Agreement,
excepting only as to an expressed written and signed waiver as to a particular
matter for a particular period of time.

     14.7 Notices. Any notices given pursuant to this Agreement shall be in
writing and shall be deemed delivered upon the earlier of (i) when received at
the address set forth below, or (ii) three (3) business days after mailed by
certified or registered mail postage prepaid and properly addressed, with return
receipt requested, or (iii) by facsimile as confirmed by certified or registered
mail. Notices shall be delivered to the respective parties as indicated:

         To NITROMED:                  NitroMed, Inc.
                                       c/o Healthcare Investments Corp.
                                       379 Thornall Street
                                       Edison, NJ 08837
                                       Attn:  CEO

         Copy to:                      Carella, Byrne, Bain, Gilfillan,
                                         Cecchi & Stewart
                                       6 Becker Farm Road
                                       Roseland, New Jersey 07068
                                       Fax no.  (201)994-1744
                                       Attn:  Elliot M. Olstein, Esq.

         To HOSPITAL:                  The Brigham and Women's Hospital, Inc.
                                       75 Francis Street
                                       Boston, Massachusetts 02115
                                       Attn: Maria I. Marmarinos
                                             Assistant Vice President/Ventures

                                       32
<Page>

         Copy to:                      Brigham and Women's Medical
                                         Center, Inc.
                                       10 Vining Street
                                       Boston, MA 02115
                                       Attn:  Office of General Counsel

     14.8 NITROMED shall not use the name of the HOSPITAL or of any HOSPITAL
staff member, employee or student or any adaptation thereof in any advertising,
promotional or sales literature without the prior written approval of HOSPITAL.

         Except that NITROMED shall be permitted to use the name of the HOSPITAL
or any HOSPITAL staff member, employee or student for the following

     (i)   as required to obtain regulatory approval for PRODUCT;

     (ii)  as required by law or BONA FIDE legal process; and

     (iii) in connection with a financing or offering of securities provided
           that HOSPITAL is permitted to review such material to determine the
           correctness thereof prior to release of the material to the general
           public.

                                       33
<Page>

     IN WITNESS WHEREOF, the parties have executed this Agreement as of the date
set forth above.

NITROMED, INC.                           THE BRIGHAM AND WOMEN'S
                                         HOSPITAL, INC.

By: /s/ JOSEPH F.X. MCGUIRL              By: /s/ WILLIAM TERRY
    --------------------------               ------------------------

Name: Joseph F.X. McGuirl                Name: William Terry
      ------------------------                ------------------------

Title: Chairman, NitroMed Inc.           Title: Senior Vice President
       -----------------------                  ----------------------

         We, Drs. Joseph Loscalzo and Jonathan Stamler, named as PRINCIPAL
INVESTIGATORS in this Agreement, attest that we have read this Agreement in its
entirety; and that we consent to the terms herein.

PRINCIPAL INVESTIGATORS

By: /S/ JOSEPH LOSCALZO                       By: /S/ JONATHAN STAMLER
    ----------------------------                  ---------------------------
        Dr. Joseph Loscalzo                           Dr. Jonathan Stamler

                                       34
<Page>

                        FIRST YEAR BUDGET AND OBJECTIVES

                                       For

                RESEARCH ON INTERMEDIARY NITRIC OXIDE METABOLISM:

             NOVEL COMPOUNDS, DELIVERY SYSTEMS, AND CELL REGULATION

                                                 Joseph Loscalza, M.D., Ph.D.
                                                 Jonathan Stamler, M.D.
                                                 Brigham and Women's Hospital
                                                 Boston, Massachusetts

                                                 March, 1992

                                       35
<Page>

                     CARDIOVASCULAR EFFECTS OF S-NO ADDUCTS

Personnel:
         Technicians (2)                                           [**]
                                                                   ======
         Postdocs (2)                                              [**]
                                                                   ======
         Administrator (1)                                         [**]
                                                                   ======
         Secretary (1)                                             [**]
                                                                   ======
Supplies:                                                          [**]
                                                                   ======
Animals:                                                           [**]
                                                                   ======
Total Direct Costs:                                                [**]
                                                                   ======
Total Indirect Costs ([**]%)                                       [**]
                                                                   ======
   Grand Total:                                                    [**]
                                                                   ======

OBJECTIVES

    --   synthesize and characterize [**] S-NO [**]
    --   examine [**] S-NO [**]
    --   [**] S-NO [**]

                                       36
<Page>

BASIC LONG-TERM PROJECT OBJECTIVES

     --  organic chemistry of [**]
         [**]
     --  cellular metabolism of [**]:
         [**]
     --  [**] of proteins
     --  [**] states

*        Over first five years; NOT dependent on milestones

                                       39
<Page>

EQUIPMENT

EPR Spectrometer                                                      [**]
                                                                      =======
Chemiluminescence Spectrometer                                        [**]
                                                                      =======
NMR Spectrometer                                                      [**]
                                                                      =======
Capillary Zone Electrophoresis                                        [**]
                                                                      =======
         w/ Indirect Fluorescence Detector
Infrared Spectrometer                                                 [**]
                                                                      -======
CC/Mass Spectrometer System                                           [**]
                                                                      =======
Quantitative Angiography System                                       [**]
                                                                      =======
Intravascular Ultrasound System                                       [**]
                                                                      =======
Microvascular Vasomotor Apparatus                                     [**]
                                                                      =======
Microvascular Permeability Equipment                                  [**]
                                                                      =======
                                                                      [**]
                                                                      =======

                                       37
<Page>

ANCILLARY PROJECTS AND BUDGETS

I.       PULMONARY EFFECTS OF S-NO ADDUCTS

Personnel:
         Technicians (2)                                           [**]
                                                                   ======
         Postdocs (2)                                              [**]
                                                                   ======
Supplies:                                                          [**]
                                                                   ======
Animals:                                                           [**]
                                                                   ======
Total Direct Costs:                                                [**]
                                                                   ======
Total Indirect Costs  ([**]%)                                      [**]
                                                                   ======
   GRAND TOTAL                                                     [**]
                                                                   ======

OBJECTIVES

         --     examine [**] S-NO [**]
                [**] NO [**]
         --     [**] NO [**] processes

II.      [**] EFFECTS OF S-NO [**]

Personnel:
         Technicians (2)                                           [**]
                                                                   ======
         Postdocs (2)                                              [**]
                                                                   ======
Supplies:                                                          [**]
                                                                   ======
Animals:                                                           [**]
                                                                   ======
Total Direct Costs:                                                [**]
                                                                   ======
Total Indirect Costs ([**]%)                                       [**]
                                                                   ======
   GRAND TOTAL                                                     [**]
                                                                   ======

                                       38
<Page>

OBJECTIVES

         -- evaluate effect of NO [**]
         -- evaluate effect of NO [**]
         -- assess effect of NO [**]

                                       39
<Page>

<Table>
<Caption>
============================================================================================================================
                          Patent Applications or Invention Disclosures of Jonathan Stamler ET AL.
----------------------------------------------------------------------------------------------------------------------------
Docket No.                              Title                       Inventors                         Status
----------------------------------------------------------------------------------------------------------------------------
<S>                     <C>                               <C>                       <C>
0627.2210000              Nitrosylation of Hortocysteine     Jonathan Stamler          Application consisting of claim and
                          As A Novel Antithrombotic          Joseph Loscalzo           abstract files April 10, 1991,
                          Mechanism                                                    Serial No. 07/683,415.

                                                                                       Application abandoned in favor of
                                                                                       continuation-in-part application,
                                                                                       Serial No. 07/339,188, filed
                                                                                       February 21, 1992, Docket No.
                                                                                       0627.2960004.
----------------------------------------------------------------------------------------------------------------------------
0627,2460000              Nitrosylation of Protein SH        Jonathan Stamler          Application filed November 14,
                          Groups And Amino Acid Residues     Joseph Loscalzo           1991, Serial No. 07/791,668.  Also
                          As A Therapeutic Modality          Daniel Simon              include the subject matter
                                                             David Siegel              pertaining to nitrosation of
                                                                                       tyrosine and other amino acids
                                                                                       (invention disclosure; Docket No.
                                                                                       0627.290000).

                                                                                       Plan to review the application  to
                                                                                       determine whether a continuation-in-part
                                                                                       application including no data  pertaining
                                                                                       to ______ amino acids should be filed.
----------------------------------------------------------------------------------------------------------------------------
0627.2470000              S-Nitroso-N-Acetylcysteine As A    Jonathan Stamler          Application consisting of claim and
                          Treatment For Airway Obstruction   Joseph Loscalzo           abstract, filed March 29, 1991,
                                                             Robert Brown              Serial No. 7/676,691.
                                                             Jeffrey Dazen
                                                                                       Application abandoned in favor of
                                                                                       continuation-in-part application,
                                                                                       Serial No. 07/804,665; filed
                                                                                       December 11, 1991; Docket No.
                                                                                       0627.2860004.
----------------------------------------------------------------------------------------------------------------------------
0627.2480000              S-Nitroso-N-Acetylcysteine As A    Jonathan Stamler          This subject matter was included in
                          Direct Biliary Smooth Muscle       Adam Slivka               the continuation-in-part
                          Relaxant (Invention disclosure)    Joseph Loscalzo           application (Docket No.
                                                                                       0627.2860004) filed on December 11,
                                                                                       1991.
</TABLE>

                                     Page 1

                                                       Revision Date: 05/22/92

<Page>

<TABLE>
<S>                     <C>                               <C>                       <C>
----------------------------------------------------------------------------------------------------------------------------
0627.2490000              Low Molecular Weight Thiols For    Daniel Simon              This subject matter was included in
                          Impotence (Invention disclosure)   Jonathan Stamler          the continuation-in-part
                                                             Joseph Loscalzo           application (Docket No.
                                                                                       0627.2860004) filed on December 11,
                                                                                       1991.
----------------------------------------------------------------------------------------------------------------------------
0627.2560000              Novel Anionic-Iron Nitrosyl        Jonathan Stamler          No application to be filed at this
                          Complexes With Smooth Muscle       David Siegel              time.  We will reconsider when
                          Relaxant And Antiplatelet          Joseph Loscalzo           additional information pertaining
                          Properties (Invention disclosure)  Daniel Simon              to synthesis and testing of
                                                                                       compounds becomes available.
----------------------------------------------------------------------------------------------------------------------------
0627.2900000              S-Nitrosothiols As Smooth Muscle   Jonathan Stamler          Continuation-in-part application,
                          Relaxants And Therapeutic Uses     David Simon               Serial No. 07/804,665, filed on
                          Thereof (CIP of 07/676,691,        Joseph Loscalzo           December 11, 1991.
                          Docket No. 0627.2470000)           Robert Brown
                                                             Jeffrey Dazen             Application was foreign filed in
                                                             Adam Slivka               the PCT and Israel, on March 30,
                                                                                       1992.
----------------------------------------------------------------------------------------------------------------------------
0627.2860004              O-Nitrosylation of Tyrosine And    Jonathan Stamler          This subject matter was included in
                          Related Compounds (Invention       Joseph Loscalzo           CIP application 07/791,668
                          disclosure)                                                  (0627.2460000), which was filed on
                                                                                       November 14, 1991.
----------------------------------------------------------------------------------------------------------------------------
0627.2960004              Nitrosylation of Homocysteine As   Jonathan Stamler          Continuation-in-part application
                          a Novel Antithrombotic Mechanism   Joseph Loscalzo           No. 07/839,188, filed February 21,
                          CIP of 07/683,415, Docket No.                                1992.
                          0627.2210000

                                                                                       Application was foreign filed in the
                                                                                       PCT and Israel on April 9, 1992
                                                                                       and April 10, 1992, respectively.
----------------------------------------------------------------------------------------------------------------------------
0627.3030000              Use of Guanylate Cyclase           Jonathan Stamler          Application filed April 8, 1992.
                          Inhibitors In The Treatment of     Joseph Loscalzo
                          Shock
----------------------------------------------------------------------------------------------------------------------------
0627.3050000              The Use of Nitric Oxide Adducts    Jonathan Stamler          Preparation of application in
                          on Artificial Surfaces to          Joseph Loscalzo           progress.  Anticipate filing in
                          Prevent Platlet Adherence and      John Folts                June 1992.
                          Thrombosis
----------------------------------------------------------------------------------------------------------------------------
</TABLE>

                                     Page 2

                                                       Revision Date: 05/22/92

<Page>

<TABLE>
<S>                     <C>                               <C>                       <C>
----------------------------------------------------------------------------------------------------------------------------
0627.3090000              The use of Nitric Oxide-Donating   Jonathan Stamler          Preparation of application in
                          Compounds as Antidotes To NO       Joseph Loscalzo           progress.  Anticipate filing in
                          Synthetase Inhibitors                                        June 1992.
----------------------------------------------------------------------------------------------------------------------------
0627.3100000              A Method For Detecting Nitric      Jonathan Stamler          Application filed April 22, 1992.
                          Oxide, Nitrososonian               Joseph Loscalzo
                          Equivalents, S-Nitrosothiols and
                          S-Nitroso-Proteins in Biological
                          Systems
----------------------------------------------------------------------------------------------------------------------------
0627.3110000              The Use of Lipophilic              Jonathan Stamler          Preparation of patentability
                          Thionitrates And Other             Joseph Loscalzo           opinion.
                          Nitroso-Derivatives To Prevent     Joseph Bonventura
                          Barnacle Attachment To Marine
                          Vessels
----------------------------------------------------------------------------------------------------------------------------
0627.3130000              Use of NO Synthetase Inhibitors    Jonathan Stamler          Preparation of patentability
                          As A Treatment for Thinitis        Joseph Loscalzo           opinion.
----------------------------------------------------------------------------------------------------------------------------
0627.3140000              Short Acting Thionitrites And      Jonathan Stamler          Prepare application.
                          Dithionitrites As Selective        Joseph Loscalzo
                          Pulmonary Vasorelaxants
----------------------------------------------------------------------------------------------------------------------------
0627.3170000              A Method For Detection And         Jonathan Stamler          Preparation of application in
                          Separation of Thiols And Their     Joseph Loscalzo           progress.  Anticipate filing in
                          S-nitrosated Derivatives In                                  June 1992.
                          Biological Samples Using
                          Capillary Electrophoresis
----------------------------------------------------------------------------------------------------------------------------
0627.3200000              Novel Uses for NO Synthetase       Jonathan Stamler          Preparation of patentability
                          Inhibitors (includes uses          Joseph Loscalzo           opinion.
                          disclosed in the 0627.3130000
                          invention disclosure other than
                          for the treatment of rhinitis)
============================================================================================================================
</TABLE>

                                     Page 3

                                                         Revision Date: 05/22/92

<Page>

BRIGHAM
AND
WOMEN'S
H O S P I T A L

                          MATERIALS TRANSFER AGREEMENT

         Agreement dated _____________ by and among _________________________
(the "Institution"), ___________________ (the "Investigator") and The Brigham
and Women's Hospital, Inc. ("Brigham") with respect to samples of a

         In consideration of the receipt from Brigham by the Institution and the
Investigator of the samples, the Institution and the Investigator agree to the
following conditions:

1.   These samples, their progeny and derivatives thereof (the "Materials")
     remain the property of Brigham.

2.   The Investigator will use the Materials solely for academic non-commercial
     research conducted by the Investigator at the Institution a research
     program described in Exhibit A hereto (the "Research Program"). Neither the
     Investigator nor the Institution will use the results of the Research
     Program, including inventions, directly or indirectly for profit-making
     purposes without the consent of the Brigham

3.   The Investigator and the Institution understand that Brigham has applied
     for a patent on the          and derivatives thereof.

4.   The Investigator will not give access to the Materials to any party not
     connected with the Research Program without written permission from
     Brigham.

5.   The Investigator and the Institution accept the Materials with the
     knowledge that they are provided without warranty of merchantability of
     fitness for a particular purpose or any other warranty, express or implied.
     The Institution agrees to defend and indemnify and hold harmless Brigham
     and its employees and agents from all claims and damages (including legal
     fees) arising from the use, storage, handling, or direct sale of the
     Materials by the Institution and/or the Investigator.

INSTITUTION:                               INVESTIGATOR:

By:_________________________________       ____________________________________

THE BRIGHAM AND WOMEN'S HOSPITAL, INC.

By:_________________________________

<Page>

                  AMENDMENT TO RESEARCH AND LICENSE AGREEMENT

     This Amendment is effective as of November 22, 1996 by and between The
Brigham and Women's Hospital, Inc. ("HOSPITAL"), having an address at 75 Francis
Street, Boston, Massachusetts 02115, and NitroMed, Inc., a Delaware Corporation
having offices at 801 Albany Street, Boston, Massachusetts 02118 ("NITROMED").

     WHEREAS, NITROMED and HOSPITAL entered into a RESEARCH AND LICENSE
AGREEMENT effective as of August 1, 1992; and

     WHEREAS, HOSPITAL and NITROMED desire to amend such RESEARCH AND LICENSE
AGREEMENT.

     NOW, THEREFORE, in consideration of the mutual promises and other good and
valuable consideration, the parties agree as follows:

1.   All fully capitalized terms in this Amendment shall have the same meaning
     as in the RESEARCH AND LICENSE AGREEMENT.

2.   Section 8.1A of the RESEARCH AND LICENSE AGREEMENT is amended and rewritten
     in its entirety to read as follows:

         8.1 (A) On all sales of PRODUCTS anywhere in the world by NITROMED, its
AFFILIATES or SUBLICENSEE, following the FIRST COMMERCIAL SALE in such country
by NITROMED its AFFILIATES or SUBLICENSEES, NITROMED shall pay HOSPITAL
royalties in accordance with the following schedule, such undertaking and
schedule having been agreed to for the purpose of reflecting and advancing the
mutual convenience of the parties. For each PRODUCT sold or distributed by
NITROMED or its AFFILIATES and SUBLICENSEES, N1TROMED shall pay to HOSPITAL one
of the following:

<Page>

          (1) (i) [**] percent ([**]%) of the NET SALES PRICE of PRODUCTS (other
          than PRODUCTS which are a diagnostic product or service) sold or
          distributed by NITROMED or its AFFILIATES in a country and or (ii)
          [**] percent ([**]%) of the NET SALES PRICE of PRODUCTS which are
          diagnostic products or diagnostic services sold or distributed by
          NITROMED or its AFFILIATES in a country so long as in each case the
          PRODUCT, its manufacture, use or sale in the country in question shall
          be subject to a VALID CLAIM of any PATENT RIGHT which is licensed
          exclusively to NITROMED in such country, or (2) (i) [**] percent
          ([**]%) of the NET SALES PRICE of PRODUCTS (other than PRODUCTS which
          are diagnostic products or diagnostic services) sold or distributed by
          NITROMED or its AFFILIATES in a country or (ii) [**] percent ([**]%)
          of the NET SALES PRICE of PRODUCTS which are diagnostic products or
          diagnostic services sold or distributed by NITROMED or its AFFILIATES,
          whenever, in each case, the PRODUCT, its manufacture, use or sale
          shall be subject to a VALID CLAIM of only such PATENT RIGHTS which are
          licensed non-exclusively to NITROMED in the country is question (the
          term non-exclusive license includes a license in which HOSPITAL
          co-owns the applicable PATENT RIGHTS with a third party(ies) and
          NITROMED does not receive an exclusive license under this Agreement
          from all of the owners), or (3) the following percentage of royalties
          received from a SUBLICENSEE for sale or distribution of a PRODUCT
          whose manufacture, use or sale is subject to a VALID CLAIM of PATENT
          RIGHTS:

          (i) [**] percent ([**]%) where HOSPITAL owns all right and title in
          and to such PATENT RIGHTS; or

          (ii) [**] percent ([**]%) where HOSPITAL does not own all right and
          title in and to such PATENT RIGHTS.

          (4) (a) For each PRODUCT sold by NITROMED in which a competing product
          employing similar technology is not available, (i) [**] percent
          ([**]%) of the NET' SALES PRICE of PRODUCTS sold or distributed by
          NITROMED or its AFFILIATES and (ii) [**] percent ([**]%) of royalties
          received from a SUBLICENSEE for salt or distribution of PRODUCT (1)
          for ten (10) years next following the FIRST COMMERCIAL SALE of any
          PRODUCT whose manufacture, use or sale shall employ or incorporate any
          HOSPITAL MATERIAL where such HOSPITAL MATERIALS are not subject to one
          or more VALID CLAIMS of any PATENT RIGHT licensed to NITROMED in such
          country or (2) for the ten (10) years next following the FIRST
          COMMERCIAL SALE of any PRODUCT whose manufacture, use or sale shall
          employ as a significant part thereof INFORMATION which is not subject
          to any VALID CLAIM of a PATENT RIGHT licensed to NITROMED in such
          country;

<Page>

     3. Section 8.2(a) of the RESEARCH AND LICENSE AGREEMENT is amended and
rewritten in its entirety to read as follows:

     8.2 (a) In the event that royalties are to be paid by NITROMED to a party
who is not an AFFILIATE of NITROMED for PRODUCT for which royalties are also due
to HOSPITAL pursuant to Paragraph 8.1A(1), 8.1A(2), 8.IA(3)(i) or 8.1 A(4)
("Other Royalties"), then the royalties to be paid to HOSPITAL by NITROMED
pursuant to such Paragraphs shall be reduced by one-half of the amount of such
Other Royalties, but in no event shall any royalties under such Paragraphs be
reduced by more than [**] percent ([**]%).

     4. The RESEARCH AND LICENSE AGREEMENT is hereby amended effective as of the
date first above written in accordance with Paragraph 14.3 thereof. Except as
amended herein or previously amended, the terms and conditions of the RESEARCH
AND LICENSE AGREEMENT remain in full force and effect as originally written.

<Page>

     IN WITNESS WHEREOF, the parties have executed this Agreement as of the date
set forth above.

<Table>
<S>                                                     <C>
NITROMED, INC.                                          THE BRIGHAM AND WOMEN'S
                                                        HOSPITAL, INC.

By:/s/ MANUEL WORCEL                                    By: /s/ SHELBY CALVERT MORSS
   -------------------------------------------              -----------------------------------------
Name:    Manuel Worcel                                  Name: Shelby Calvert Morss
         ------------------------------------                ----------------------------------------
Title:   President and Chief Executive Officer          Title: Vice President, Ventures Department
      ----------------------------------------                 --------------------------------------
</Table>

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