<PAGE>

                                                                   Exhibit 10.15
                                                                  EXECUTION COPY

              RESEARCH, DEVELOPMENT AND COMMERCIALIZATION AGREEMENT

                                     BETWEEN

                      PREDIX PHARMACEUTICALS HOLDINGS, INC.

                                       AND

              CYSTIC FIBROSIS FOUNDATION THERAPEUTICS INCORPORATED

PORTIONS OF THIS EXHIBIT WERE OMITTED AND HAVE BEEN FILED SEPARATELY WITH THE
SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.

<PAGE>



              Research, Development and Commercialization Agreement

                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                                                     Page
<S>                                                                                                  <C>
ARTICLE I - DEFINITIONS...........................................................................     2

ARTICLE II - RESEARCH PROGRAM.....................................................................     8
   2.1      Commencement; Objective...............................................................     8
   2.2      Term..................................................................................     9
   2.3      Research Diligence....................................................................     9
   2.4      Research Plan.........................................................................     9
   2.5      Joint Research Committee..............................................................    10
   2.6      Exchange of Information...............................................................    11

ARTICLE III - PAYMENTS............................................................................    12
   3.1      Staffing and Research Support Payments................................................    12
   3.2      Payments..............................................................................    15
   3.3      Records...............................................................................    16

ARTICLE IV - COMMERCIALIZATION; ROYALTIES.........................................................    17
   4.1      Discovery and Commercialization of a CFTR Corrector-Based Product;
   Commercialization of P2(Y)2 Product............................................................    17
   4.2      Due Diligence.........................................................................    18
   4.3      Royalties.............................................................................    18
   4.4      Sales Reports.........................................................................    18

ARTICLE V - CONFIDENTIALITY.......................................................................    20
   5.1      Undertaking...........................................................................    21
   5.2      Exceptions............................................................................    22
   5.3      Publicity.............................................................................    23

ARTICLE VI - PUBLICATION..........................................................................    24

ARTICLE VII - INDEMNIFICATION.....................................................................    26
   7.1      Indemnification by Predix.............................................................    26
   7.2      Claims Procedures.....................................................................    26

ARTICLE VIII - PATENTABLE INVENTIONS..............................................................    28
   8.1      Ownership.............................................................................    28
   8.2      Preparation...........................................................................    28
   8.3      Costs.................................................................................    29

ARTICLE IX - TERM AND TERMINATION.................................................................    29
   9.1      Term..................................................................................    29
   9.2      Termination of the Research Programs Without Cause....................................    29
   9.3      Termination of the Research Program by CFFT for Cause.................................    29
   9.4      Termination of the Research Program by Predix for Cause...............................    30
   9.5      General Effect of Termination.........................................................    31
</TABLE>

PORTIONS OF THIS EXHIBIT WERE OMITTED AND HAVE BEEN FILED SEPARATELY WITH THE
SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.

                                      - i -
<PAGE>



<TABLE>
<S>                                                                                                   <C>
   9.6      Consequences of an Interruption.......................................................    31

ARTICLE X - REPRESENTATIONS AND WARRANTIES........................................................    32
   10.1     Representations and Warranties of Predix..............................................    32
   10.2     Representations and Warranties of CFFT................................................    32

ARTICLE XI - MISCELLANEOUS PROVISIONS.............................................................    33
   11.1     Governing Law, and Jurisdiction.......................................................    33
   11.2     Waiver................................................................................    33
   11.3     Force Majeure.........................................................................    33
   11.4     Severability..........................................................................    34
   11.5     Government Acts.......................................................................    34
   11.6     Assignment............................................................................    34
   11.7     Counterparts..........................................................................    35
   11.8     No Agency.............................................................................    36
   11.9     Notice................................................................................    36
   11.10    Headings..............................................................................    37
   11.11    Authority.............................................................................    37
   11.12    Entire Agreement......................................................................    38
   11.13    Notice of Pharmaceutical Side-Effects.................................................    38
</TABLE>

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SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.

                                     - ii -
<PAGE>



              RESEARCH, DEVELOPMENT AND COMMECIALIZATION AGREEMENT

      This Agreement (this "Agreement") is made on this 7th day of March, 2005
(the "Effective Date"), between Predix Pharmaceuticals Holdings, Inc.
("Predix"), a Delaware corporation with principal offices at 10K Gill Street,
Woburn, MA 01801, and Cystic Fibrosis Foundation Therapeutics Incorporated, a
Delaware corporation with its principal offices at 6931 Arlington Road,
Bethesda, Maryland 20814 ("CFFT"). Collectively, Predix and CFFT shall be
referred to hereinafter as the "Parties".

      WHEREAS, Predix has expertise in 3D technology and the discovery and
development of small molecule compounds addressing a variety of diseases; and

      WHEREAS, CFFT is significantly focused on the discovery and development of
methods of treatment of cystic fibrosis, to which CFFT and its Affiliates bring
significant scientific and human resources and financial support; and

      WHEREAS, CFFT wishes to support the Research Programs specified
hereinafter to be undertaken by Predix;

      NOW, THEREFORE, in consideration of the mutual covenants set forth in this
Agreement, and other good and valuable consideration, the Parties agree as
follows:

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CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.

<PAGE>



                            ARTICLE I - DEFINITIONS

      For purposes of this Agreement, the terms defined in this Article 1 shall
have the following meanings whether used in their singular or plural forms. Use
of the singular shall include the plural and vice versa, unless the context
requires otherwise:

      1.1 "Affiliate" shall mean, with respect to any Person, any other Person
who directly or indirectly, by itself or through one or more intermediaries,
controls, or is controlled by, or is under direct or indirect common control
with, such Person. The term "control" means the possession, direct or indirect,
of the power to direct or cause the direction of the management and policies of
a Person, whether through the ownership of voting securities, by contract or
otherwise. Control will be presumed if one Person owns, either of record or
beneficially, more than fifty percent (50%) of the voting stock of any other
Person. For the avoidance of any doubt, the Cystic Fibrosis Foundation and CFFT
are considered to be Affiliates.

      1.2 "Agreement" means this agreement, together with all appendices,
exhibits and schedules hereto, and as the same may be amended or supplemented
from time to time hereafter by a written agreement duly executed by authorized
representatives of each party hereto.

      1.3 "Budget" shall mean the total amount to be paid by CFFT to Predix for
each of Research Program I and Research Program II as specified in Article III.

      1.4 "CF" means the disease known as Cystic Fibrosis.

      1.5 "CF Field" means the treatment of humans diagnosed with CF.

      1.6 "CFTR" shall mean a CF transmembrane conductance regulator protein
which has the biological effect of transporting molecules across human cellular
membranes.

PORTIONS OF THIS EXHIBIT WERE OMITTED AND HAVE BEEN FILED SEPARATELY WITH THE
SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.

                                      - 2 -
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      1.7 "[*******************] Efforts" shall have the definition set forth in
Section 4.2.

      1.8 "Controlled" (except in the context of Section 1.1) shall mean the
legal authority or right of a party hereto to grant a license or sublicense of
intellectual property rights to another party hereto, or to otherwise disclose
proprietary or trade secret information to such other party, without breaching
the terms of any agreement with a Third Party, infringing upon the intellectual
property rights of a Third Party, or misappropriating the proprietary or trade
secret information of a Third Party.

      1.9 "Corrector" shall mean a compound which, as its principal mode of
therapeutic action, modulates the biological effect of CFTR by increasing the
amount of functional AF508 CFTR present at the apical cell membrane.

      1.10 "Effective Date" shall mean the date specified in the first paragraph
of this Agreement.

      1.11 "Field" shall mean the treatment of conditions or diseases in the CF
Field and the Pulmonary Field.

      1.12 "First Commercial Sale" shall mean the first sale of a P2(Y)2 Product
by Predix or an Affiliate, licensee or sublicensee of Predix in a country in the
Territory following Regulatory Approval of the P2(Y)2 Product in that country
or, if no such Regulatory Approval or similar marketing approval is required,
the date upon which the P2(Y)2 Product is first commercially launched in that
country.

      1.13 "FTE" shall mean the equivalent of the work of one Predix scientist
or other project managerial professional, full time for one year, on or directly
related to the Research

PORTIONS OF THIS EXHIBIT WERE OMITTED AND HAVE BEEN FILED SEPARATELY WITH THE
SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.

                                      - 3 -
<PAGE>



Program. Activities included in calculating FTE's shall [***********************
*******************************************************************************
**********************************].

      1.14 "Hit" shall have the meaning ascribed to it in Section 3.1.2 of this
Agreement.

      1.15 "Interruption" shall occur (i) if at any time before the First
Commercial Sale of a P2(Y)2 Product, Predix, its Affiliates and sublicensees,
all cease to conduct, or have conducted, research activities associated with the
development of such Product for a period of [*******************************];
and (ii) as specified in Section 4.1.1.

      1.16 "Joint Research Committee" or "JRC" shall have the meaning ascribed
to it in Section 2.5 of Agreement.

      1.17 "Net Sales" with respect to any product shall mean the gross amount
invoiced by the selling party and its Affiliates, licensees or sublicensees for
products sold in bona fide, arms-length transactions to Third Parties for use in
the Field, less (i) quantity and/or cash discounts from the gross invoice price
which are actually allowed or taken; (ii) freight, postage and insurance
included in the invoice price; (iii) amounts repaid or credited by reasons of
rejections or return of goods or because of retroactive price reductions
specifically identifiable to such product; (iv) amounts payable resulting from
government (or agency thereof) mandated rebate programs; (v) third-party rebates
or charge-backs to the extent actually allowed; (vi) invoiced customs duties and
sales taxes (excluding income, value-added and similar taxes), if any, actually
paid and directly related to the sale that are not reimbursed by the buyer; and
(vii) any other specifically identifiable amounts included in the product's
gross invoice price that should be credited for reasons substantially equivalent
to those listed above; all as determined in

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SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.

                                      - 4 -
<PAGE>



accordance with the selling party's usual and customary accounting methods,
which are in accordance with generally accepted accounting principles.

            In the case of any sale or other disposal of a product between or
among the selling party and its Affiliates, licensees and sublicensees, for
resale, Net Sales shall be calculated as above [********************************
**********************************************];

            In the case of any sale which is not invoiced or is delivered before
invoice, Net Sales shall be calculated at the time of shipment or when the
product is paid for, if paid for before shipment or invoice;

            In the case of any sale or other disposal for value, such as barter
or counter-trade, of any product, or part thereof, other than in an arm's length
transaction exclusively for money, Net Sales shall be calculated as above on the
value of the consideration received;

            In the event the product is sold in a finished dosage form
containing the product in combination with one or more other active ingredients
(a "Combination Product"), the Net Sales of the product, for the purposes of
determining royalty payments, shall be determined [*****************************
********************************************************************************
********************************************************************************
********************************************************************************
********************************************************************************
********************************************************************************
********************************************************************************
********************************************************************************
********************************************************************************

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SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.

                                      - 5 -
<PAGE>


********************************************************************************
*****************************************************************************].

      1.18 "Patents" means all existing patents and patent applications and all
patent applications hereafter filed, including any continuation,
continuation-in-part, division, provisional or any substitute applications, any
patent issued with respect to any such patent applications, any reissue,
reexamination, renewal or extension (including any supplementary protection
certificate) of any such patent, and any confirmation patent or registration
patent or patent of addition based on any such patent, and all foreign
counterparts of any of the foregoing.

      1.19 "Person" means any individual, corporation, partnership, association,
joint-stock company, trust, unincorporated organization or government or
political subdivision thereof.

      1.20 "Predix CF Technology" shall mean all data, technical information,
know-how, inventions (whether or not patented) trade secrets, processes and
methods discovered or developed, and Controlled by Predix or its Affiliates, in
the performance of the Research Program under this Agreement, including without
limitation, the [***************************************************]; provided,
however, that notwithstanding the foregoing, the term "Predix CF Technology"
shall not include any data, technical information, know-how, inventions (whether
or not patented) trade secrets, processes or methods owned or Controlled by
Predix prior to, or outside of, Predix's performance of the Research Program
under this Agreement, including without limitation, Predix's general receptor
and ion channel modeling technology, or computational drug discovery, drug
optimization and drug design technology, or any enhancements or improvements to
any of the foregoing.

      1.21 "Predix Patents" shall mean any Patents Controlled by Predix or its
Affiliates claiming Predix CF Technology.

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SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
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OMISSIONS.

                                      - 6 -
<PAGE>



      1.22 "Prime Rate" shall mean [******************************************
***************************].

      1.23 "Pulmonary Field" shall mean the treatment of diseases of the human
pulmonary tract or lungs, other than CF.

      1.24 "P2Y(2) Product" shall have the meaning set forth in Section 2.1.

      1.25 "Regulatory Approval" shall mean, with respect to any country, all
authorizations by the appropriate governmental entity or entities necessary for
commercial sale of a pharmaceutical product in that country including, without
limitation and where applicable, approval of labeling, price, reimbursement and
manufacturing. "Regulatory Approval" in the United States shall mean final
approval of a new drug application pursuant to 21 CFR Section 314, permitting
marketing of the P2(Y)2 Product in interstate commerce in the United States.
"Regulatory Approval" in the European Union shall mean final approval of a
Marketing Authorization Application, or equivalent.

      1.26 "Research Plan" shall have the meaning set forth in Section 2.4
hereof.

      1.27 "Research Program I" shall have the meaning set forth in Section 2.1.

      1.28 "Research Program II" shall have the meaning set forth in Section
2.1.

      1.29 "Research Programs" shall mean collectively all research activities
undertaken under this Agreement relating to Research Program I and Research
Program II.

      1.30 "Research Termination Date" shall mean the date which is
[***************] following the Effective Date for Research Program I and the
date which is [**********

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OMISSIONS.

                                      - 7 -
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*******] following the Effective Date for Research Program II, in both cases
subject to extension as provided in Section 2.2.

      1.31 "Territory" shall mean worldwide.

      1.32 "Third Party" shall mean any person or entity which is not a party or
an Affiliate of any party to this Agreement.

                         ARTICLE II - RESEARCH PROGRAM

      2.1 COMMENCEMENT; OBJECTIVE.

      Predix will be responsible for the conduct of the Research Programs as set
forth herein. CFFT will provide the financial support hereinafter specified, and
consultation and advice as provided herein through its participation on the JRC
as provided below. The Research Program will consist of two sets of separate
activities, as set forth in the Research Plan, and generally described as
follows: (i) Predix will use its 3D technology and modeling expertise to model
the 3D structure of the CFTR (such activities are the "Research Program I") and
(ii) Predix will use its 3D GPCR technology to discover a small-molecule P2Y(2)
agonist that once optimized will be a novel compound for the treatment of CF
(such activities are "Research Program II" and any product containing a
small-molecule P2Y(2) agonist discovered during the performance of Research
Program II, whether or not the molecule has been further optimized, is a "P2Y(2)
Product").

      Following the successful completion of Research Program I (or prior to its
completion if the Parties so desire), the Parties agree to negotiate in good
faith towards an agreement pursuant to which a molecule that will act as a CFTR
Corrector will be discovered, optimized, developed

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OMISSIONS.

                                      - 8 -
<PAGE>



and commercialized, all as more fully set forth in Section 4.1. Subject to
CFFT's rights in the event of an Interruption pursuant to Section 9.6 of this
Agreement, Predix shall have exclusive rights to further develop and
commercialize all P2Y(2) Products.

      2.2 TERM.

      The Research Programs shall commence on the Effective Date and will
conclude on the Research Termination Date, unless extended by agreement of the
Parties, or unless earlier terminated in accordance with the provisions of
Article IX hereof. The Parties may discuss at any time whether, and upon what
basis, the Research Program might be extended beyond the initial Research
Termination Date.

      2.3 RESEARCH DILIGENCE.

      Predix will [***********************************************************
*******], to accomplish the goals of the Research Programs. Predix will dedicate
to the Research Programs at least that level of staffing referenced in Section
3.1 hereof, and expects to employ an appropriate combination of experience and
training in the CF Field.

      2.4 RESEARCH PLAN.

            Predix and CFFT have agreed upon an overall research plan for the
Research Programs, a copy of which is attached to this Agreement as Exhibit 2.4.
The JRC will review and evaluate the Research Plan, taking into consideration
ongoing research outcomes and other scientific and commercial developments, at
each meeting of the JRC after the Effective Date, and any resulting
modifications will be incorporated into the Research Plan (the original plan,
and any such modifications are referred to herein as the "Research Plan").
Modifications to the Research Plan may be proposed by either Predix or CFFT and
must be approved by [*******]

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SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
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OMISSIONS.

                                      - 9 -
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before being adopted. Any modification to the Research Plan proposed by [******]
that would [********************************************************************
*****************************************************************************],
shall not be adopted without the approval of [*****], which will act
expeditiously on any such proposal.

      2.5 JOINT RESEARCH COMMITTEE.

            2.5.1 Composition and Purposes. Predix and CFFT shall establish a
Joint Research Committee ("JRC") consisting of at least six (6) representatives
(as may be increased or decreased by the JRC), half of whom shall be designated
from time to time by each party. Each party shall choose a Program Coordinator
who may be changed from time to time by designation of each party. The Program
Coordinator for Predix shall be [*********]. The Program Coordinator for CFFT
shall be [******************]. If the JRC chooses to designate a Committee
Chair, the Chair will be [******************]. The JRC shall meet formally no
less frequently than once in each three (3) month period during the Research
Program, and at such time and location, as may be established by the Committee.
However, the JRC will make its schedule flexible in order to foster the
successful completion of the Research Programs. The JRC shall meet for the
following purposes:

                  (i) to review and discuss the Research Plan and evaluate any
            proposed revisions to any of those plans;

                  (ii) to determine whether milestones have been achieved; and

                  (iii) to provide guidance to the research team if such
            guidance is needed on next steps to implement the Research Programs.

PORTIONS OF THIS EXHIBIT WERE OMITTED AND HAVE BEEN FILED SEPARATELY WITH THE
SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.

                                     - 10 -
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            At least [**********] working days prior to each JRC meeting, Predix
will send a written report to CFFT detailing the progress made in the respective
Research Programs during the preceding quarter. Within [**************] days
after the date of each meeting, Predix shall prepare and deliver minutes of the
meeting to the members of the JRC, setting forth, inter alia, all decisions of
the JRC, and including as an attachment the report on the progress of work
performed required by this Section 2.5.1.

            2.5.2 MILESTONE DECISION-MAKING. The JRC shall determine whether or
not milestone events have been achieved. Each of Predix and CFFT shall have one
vote on such matter, to be exercised by their respective Program Coordinators.
In the event a deadlock occurs or whether or not a milestone event has been
successfully completed, the Parties shall mutually select a Third Party who
shall make such determination. The determination of such party shall be binding
on the Parties.

            Each party shall retain the rights, powers, and discretion granted
to it under this Agreement, and the JRC shall not be delegated or vested with
any such rights, powers or discretion except as expressly provided in this
Agreement. The JRC shall not have the power to amend or modify this Agreement,
which may only be amended or modified as provided in Section 11.12.

      2.6 EXCHANGE OF INFORMATION.

            Predix will share information with the JRC when available and
necessary to facilitate mutual understanding of the status of the Research
Program and decision-making in connection therewith.

PORTIONS OF THIS EXHIBIT WERE OMITTED AND HAVE BEEN FILED SEPARATELY WITH THE
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OMISSIONS.

                                     - 11 -
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                             ARTICLE III - PAYMENTS

      3.1 STAFFING AND RESEARCH SUPPORT PAYMENTS.

            CFFT will make the payments to Predix specified below during the
Term in support of the Research Programs under this Agreement.

            3.1.1 RESEARCH PROGRAM I

<TABLE>
<CAPTION>
                                                         FTE Research
                                                        Funding (# FTEs
                                       Estimated           charged                              Total
                    Item in              Time             at [*******       Out-sourced        Budgeted
                   Exhibit 2.4         (Months)*          **********]        activities         Amount
                   -----------        -----------       ---------------     -----------      -------------
<S>                <C>                <C>               <C>                 <C>              <C>
a) [******************]: to be paid on the date of execution                                 $   2,000,000

b) Base Research Funding:

[**********        [*******]          [*******]          [*********]         [********       [*********]
***********                                                                  *********
****                                                                         ********
***********                                                                  ********
*********                                                                    ********]
***********
*********
*******
*********]

[*********]        [*********]        [*********]        [*********]         [*********]     [*********]
</TABLE>

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OMISSIONS.

                                     - 12 -
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<TABLE>
<S>                <C>                <C>                <C>                 <C>             <C>
[********                                                                    [********
*********                                                                    ********]
**********
***********
**********
***********
********
***********]

[********          [***]              [********]         [********]          [********       [********]
*********                                                                    [********]
**********                                                                   [********]
********
*********
**********]

[********          [***]              [********]         [********]          [********       [********]
*********                                                                    [********]
**********                                                                   [********]
********
*********
**********]

c) Milestones:
</TABLE>

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OMISSIONS.

                                     - 13 -
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<TABLE>
<S>                                                                                            <C>
[************************************************************                                  [********]
****]

[************************************************************                                  [********]
****]

[************************************************************                                  [********]
****]

Aggregate Budgeted Amount for Research Program I                                               [********]
</TABLE>

Each milestone shall be due and payable [************] after it is achieved.
All milestones under Research Program I that are not achieved prior to the
Research Termination Date will nevertheless be paid by CFFT to Predix if
achieved within [********] after the Research Termination Date.

*Periods are estimates. The parties anticipate that particular aspects of the
Research Programs may take longer than the periods indicated but that the
Research Programs will likely be completed on or prior to the Research
Termination Date.

**This payment shall be reduced to [********] if this milestone is accomplished
before the milestone in subparagraph (c)(2) above ("Milestone (c)(2)"); and, the
remaining [********] shall be added to the amount specified for Milestone (c)(2)
and paid to Predix upon the accomplishment of Milestone (c)(2).

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OMISSIONS.

                                     - 14 -
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            3.1.2 RESEARCH PROGRAM II

      The total Budget for Research Program II shall be [*****] consisting of up
to [******] FTEs per year and/or the expense of out-sourced activities, for the
[******] period beginning on the Effective Date. FTEs budgeted amounts shall be
billed by Predix to CFFT [******]; provided that, total FTE billing in
[*************************] during which Research Program II will be conducted
will not exceed [*****] FTEs billable at [****] per FTE in each such
[*************] period. If Predix does not identify a hit for the P2Y(2)
receptor that has an [***************] in a [**************] (or an equivalent
assay) (a "Hit"), within the [***************] period following the Effective
Date of this Agreement, CFFT will terminate payments for FTE payments for
Research Program II, after payment for the FTE's allocable to the initial
[********] period until a Hit is identified; provided that, FTE payments for the
additional [***********] period budgeted for Research Program II will resume
when a Hit is identified if such identification occurs within
[******************] of such termination.

      3.2 PAYMENTS.

            Budgeted payments due on account of internal FTEs shall be made by
CFFT [******] within [***********] of the receipt of invoices for such amounts.
Budgeted payments on account of external costs shall be made by CFFT [******] in
arrears within [**********] following receipt of an invoice for such external
costs accompanied by usual and customary documentation of such costs. Amounts
budgeted for outsourced activities may be reallocated among different outsourced
activities so long as the total costs to be reimbursed by CFFT do not exceed the
total amount budgeted for outsourced activities. In addition to the amounts
indicated above for outsourced activities, CFFT shall arrange for and direct pay
a service provider for the [******************] services described in Section
10.2.1 of Exhibit 2.4. All payments shall be made without deduction for
withholding or other similar taxes, in United States dollars to the

PORTIONS OF THIS EXHIBIT WERE OMITTED AND HAVE BEEN FILED SEPARATELY WITH THE
SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.

                                     - 15 -
<PAGE>



credit of such bank account as may be designated by Predix in writing to CFFT.
Any payments which fall due on a date which is a legal holiday in the State of
Maryland may be made on the next following day which is not a legal holiday in
the State of Maryland. On or before each of [**************************] Predix
will provide CFFT with an accounting of all internal FTE costs (consisting of
the names and dates worked for those persons who are included within the
reimbursed FTE costs) and outsourcing costs incurred under the Research Programs
during the most recently concluded calendar year. Internal FTE costs will be
calculated at an annual rate of [******] per FTE. Costs incurred will be
compared with funds provided by CFFT on account of that year, and any excess of
funds paid to Predix over costs incurred will be refunded to CFFT within
[******] or, as to amounts due on account of [*****] activities, applied as
a credit against amounts due for [*****] activities.

      3.3 RECORDS.

            Predix shall keep accurate records and books of accounts containing
all data reasonably required for the calculation and verification of the number
of FTE's employed in the performance of the Research Programs, and outsourcing
costs incurred by Predix in the Research Program during the term of this
Agreement and for a period of [*************] thereafter. CFFT, through an
independent accounting firm unaffiliated with either CFFT or Predix, shall have
the right at its expense to audit Predix's relevant records to verify compliance
with FTE and other research funding allocation requirements hereunder. At CFFT's
request, Predix shall make those records available, no more than [********],
during reasonable working hours, for review by a recognized independent
accounting firm acceptable to both Parties, at CFFT's expense, for the sole
purpose of verifying the accuracy of those records in the calculation of
Research Program FTEs and outsourcing costs. Predix shall not, however, be
required to retain or make available to CFFT or its accountants, any such
records or books of account for [******************************]

PORTIONS OF THIS EXHIBIT WERE OMITTED AND HAVE BEEN FILED SEPARATELY WITH THE
SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.

                                     - 16 -
<PAGE>



*******] beyond [***************] from the Research Termination Date. CFFT
shall cause the accounting firm to retain all such information in confidence.
Such accounting firm shall report to CFFT only the existence and amount of any
variance between the amount paid and the amount that was actually due hereunder.
In the event that the aggregate costs actually chargeable to the Research
Programs during any calendar year are less than the amount previously advanced
to Predix by CFFT and properly attributable to that calendar year (a "Negative
Difference"), in addition to reimbursing CFFT for the Negative Difference
[*************************** **************************], if the Negative
Difference [*************************] of the amounts properly attributable to
that calendar year, then Predix shall [*****************
****************************************************] in the review.

                    ARTICLE IV - COMMERCIALIZATION; ROYALTIES

      4.1 DISCOVERY AND COMMERCIALIZATION OF A CFTR CORRECTOR-BASED PRODUCT;
COMMERCIALIZATION OF P2(Y)2 PRODUCT.

            4.1.1 DISCOVERY AND COMMERCIALIZATION OF A CFTR CORRECTOR-BASED
PRODUCT. Following the completion of the work set forth in the Research Plan
relating to Research Program I (or prior to its completion if the Parties so
desire), the Parties agree to negotiate in good faith, for a period of up to
[*************], towards an agreement pursuant to which Predix will, building
upon the Predix CF Technology, explore a structure-based route for the discovery
and commercialization of a molecule that will act as a CFTR Corrector with the
financial support of CFFT and subject to a royalty or similar obligation to
CFFT. Other than participating in such good faith negotiations, however, neither
party shall be obligated to enter into such an agreement. If the Parties do not
enter into such an agreement during such [*******

PORTIONS OF THIS EXHIBIT WERE OMITTED AND HAVE BEEN FILED SEPARATELY WITH THE
SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.

                                     - 17 -
<PAGE>


***] period, an Interruption shall be deemed to have occurred with respect to
Research Program I with the attendant consequences provided for in Section 9.6.

            4.1.2 COMMERCIALIZATION OF P2Y(2) PRODUCT. Except in the event of an
Interruption, Predix and/or its licensees and sublicensees shall have exclusive
rights to market, sell and distribute any or all P2Y(2) Products throughout the
Territory.

      4.2 DUE DILIGENCE.

            Predix shall[**********************************************
****************************************************************************] to
effect introduction of P2(Y)2 Products into major markets in North America and
Europe [************************************************************************
********************************************************************************
**********************************************************]  Efforts").

      4.3 ROYALTIES.

            Within [**********] following the [***************] of the first
P2(Y)2 Product, Predix shall pay a [********************************]. If
aggregate Net Sales of such P2(Y)2 Product in the [***************] following
the month the [*************************] is granted ("Relevant [**]") exceed
$250 million, Predix shall pay to CFFT an additional [********************]; or,
if such Net Sales exceed [************], Predix shall pay to CFFT an additional
[***********************] (in lieu of the [**********] payment). The additional
royalty shall be paid within [********] following the close of the relevant
[*************].

      4.4 SALES REPORTS.

PORTIONS OF THIS EXHIBIT WERE OMITTED AND HAVE BEEN FILED SEPARATELY WITH THE
SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.

                                     - 18 -
<PAGE>



            (a) Within [*********] after the conclusion of the Relevant [**],
Predix shall furnish or cause to be furnished to CFFT a written report or
reports covering the Relevant [**] showing, for Net Sales, (i) the Net Sales for
the first P2(Y)2 Product in each country in the world during the reporting
period by Predix and each Affiliate, licensee and sublicensee; (ii) any royalty,
payable in U.S. dollars ("Dollars"), which shall have accrued under Section 4.3
hereof in respect of such sales and the basis of calculating the royalty; and
(iii) the exchange rates used in converting into Dollars, from the currencies in
which sales were made, any amounts which are included within Net Sales; and (iv)
dispositions of P2(Y)2 Products other than pursuant to sale for cash. With
respect to sales of P2(Y)2 Products invoiced in Dollars, the Net Sales amounts
and the amounts due to CFFT hereunder shall be expressed in Dollars. With
respect to sales of P2(Y)2 Products invoiced in a currency other than Dollars,
the Net Sales and amounts due to CFFT hereunder shall be expressed in the
domestic currency of the party making the sale, together with the Dollar
equivalent of the amount payable to CFFT, calculated by translating foreign
currency sales into U.S. dollars at the exchange rates for the [**************
************************************************************]. If any licensee
or sublicensee makes any sales invoiced in a currency other than its domestic
currency, the Net Sales shall be converted to its domestic currency in
accordance with the licensee's or sublicensee's normal accounting principles.
Predix shall keep accurate records in sufficient detail to enable the amounts
due hereunder to be determined and to be verified by CFFT.

            (b) Amounts shown to have accrued by each sales report provided for
under Section 4.4(a), above, shall be due and payable on the date that sales
report is due.

            (c) All payments shall be made in Dollars.

            (d) Upon the written request of CFFT, at CFFT's expense and not more
than [***] time in the [*************] period following the receipt by CFFT of
the report required

PORTIONS OF THIS EXHIBIT WERE OMITTED AND HAVE BEEN FILED SEPARATELY WITH THE
SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.

                                     - 19 -
<PAGE>



under Section 4.4(a), Predix shall permit an independent accountant of national
prominence selected by CFFT, to have access during normal business hours to
those records of Predix as may be reasonably necessary to verify the accuracy of
the report furnished by Predix pursuant to this Section 4.4. The report prepared
by such independent accountant, a copy of which shall be sent or otherwise
provided to Predix by such independent accountant at the same time it is sent or
otherwise provided to CFFT, shall contain the conclusions of such independent
accountant regarding the existence and amount of any variance between the amount
paid and the amount that was actually due hereunder. If such independent
accountant's report shows any underpayment, Predix shall remit to CFFT within
[************] after Predix's receipt of such report (i) the amount of such
underpayment [******************************************************************
*************************************************] and (ii) if such underpayment
exceeds [*************] of the total amount owed, [****************************
*********************************************************************
********************************************************************************
***************]. Any overpayment shall be refunded by CFFT to Predix within
[***********] following CFFT's receipt of the auditor's report. CFFT agrees
that all information subject to review under this Section 4.4 is confidential
and that CFFT shall retain and cause its accountant to retain all such
information in confidence.

            (e) In case of any delay in payment by Predix to CFFT not occasioned
by Force Majeure, [**********************************************************
**********************************************].

                          ARTICLE V - CONFIDENTIALITY

PORTIONS OF THIS EXHIBIT WERE OMITTED AND HAVE BEEN FILED SEPARATELY WITH THE
SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.

                                     - 20 -
<PAGE>



      5.1 UNDERTAKING.

            During the term of this Agreement, each party shall keep
confidential, and other than as provided herein, shall not use or disclose,
directly or indirectly, any trade secrets, confidential or proprietary
information, or any other knowledge, information, documents or materials, owned,
developed or possessed by the other party, whether in tangible or intangible
form, the confidentiality of which such other party takes reasonable measures to
protect ("Confidential Information"). Neither CFFT nor Predix will use the other
party's Confidential Information except as expressly permitted in this
Agreement:

                  (a) Each party shall take any and all lawful measures to
            prevent the unauthorized use and disclosure of the other party's
            Confidential Information, and to prevent unauthorized persons or
            entities from obtaining or using that Information.

                  (b) Each party will refrain from directly or indirectly taking
            any action which would constitute or facilitate the unauthorized use
            or disclosure of the other party's Confidential Information. Each
            party may disclose that Information to its officers, employees and
            agents, to authorized licensees and sublicensees, and to
            subcontractors in connection with the development or manufacture of
            P2(Y)2 Products, to the extent necessary to enable such parties to
            perform their obligations hereunder or under the applicable license,
            sublicense or subcontract, as the case may be; provided, that such
            officers, employees, agents, licensees, sublicensees and
            subcontractors have entered into appropriate confidentiality
            agreements for secrecy and non-use of such Confidential

PORTIONS OF THIS EXHIBIT WERE OMITTED AND HAVE BEEN FILED SEPARATELY WITH THE
SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.

                                     - 21 -
<PAGE>



            Information which by their terms shall be enforceable by injunctive
            relief at the instance of the disclosing party.

                  (c) Each party shall be liable for any unauthorized use and
            disclosure of the other party's Confidential Information by its
            officers, employees and agents and any such sublicensees and
            subcontractors.

      5.2 EXCEPTIONS.

            Notwithstanding the foregoing, the provisions of Section 5.1 hereof
shall not apply to Confidential Information which the receiving party can
conclusively establish:

                  (a) has entered the public domain without such party's breach
            of any obligation owed to the disclosing party;

                  (b) is permitted to be disclosed by the prior written consent
            of the disclosing party;

                  (c) has become known to the receiving party from a source
            other than the disclosing party, other than by breach of an
            obligation of confidentiality owed to the disclosing party;

                  (d) is independently developed by the receiving party without
            breach of this Agreement; or

                  (e) is required to be disclosed by the receiving party to
            comply with applicable laws or regulations, to defend or prosecute
            litigation or to comply with governmental regulations, provided that
            the receiving party provides prior written

PORTIONS OF THIS EXHIBIT WERE OMITTED AND HAVE BEEN FILED SEPARATELY WITH THE
SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.

                                     - 22 -
<PAGE>



            notice of such disclosure to the disclosing party and takes
            reasonable and lawful actions to avoid or minimize the degree of
            such disclosure.

            Either Predix or CFFT may at any time, by notice in writing to the
other party, waive any or all of the confidentiality obligations to which the
other party is subject hereunder, for any length or time or with respect to any
specific information.

      5.3 PUBLICITY.

            The Parties will agree upon the timing and content of any initial
press release or other public communications relating to this Agreement and the
transactions contemplated herein.

                  (a) Except to the extent already disclosed in that initial
            press release or other public communication, no public announcement
            concerning the terms of this Agreement or concerning the
            transactions described herein shall be made, either directly or
            indirectly, by Predix or CFFT, except (i) as may be legally required
            by applicable laws, regulations, or judicial order, (ii) as may be
            required by the rules of any stock exchange on which such party's
            securities are listed, or (iii) if limited to the fact that the
            Research Programs exist, that research is in progress, and its
            anticipated completion without first obtaining the approval of the
            other party and agreement upon the nature, text, and timing of such
            announcement, which approval and agreement shall not be unreasonably
            withheld.

                  (b) The party desiring to make any such public announcement
            shall provide the other party with a written copy of the proposed
            announcement in

PORTIONS OF THIS EXHIBIT WERE OMITTED AND HAVE BEEN FILED SEPARATELY WITH THE
SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.

                                     - 23 -
<PAGE>



            sufficient time prior to public release to allow such other party to
            comment upon such announcement, prior to public release.

                            ARTICLE VI - PUBLICATION

      Each of Predix and CFFT reserves the right to publish or publicly present
the data generated during the performance of the Research Programs (the
"Results"), subject to the following terms and conditions. The party proposing
to publish or publicly present the Results (the "publishing party") will submit
a draft of any proposed manuscript or speech to the other party (the
"non-publishing party") for comments at least [*************] prior to
submission for publication or oral presentation. The non-publishing party shall
notify the publishing party in writing within [************] of receipt of such
draft whether such draft contains (i) information of the non-publishing party
which it considers to be confidential under the provisions of Article V hereof,
(ii) information that if published would have an adverse effect on a patent
application which the non-publishing party intends to file, or (iii) information
which the non-publishing party reasonably believes would be likely to have a
material adverse impact on the development or commercialization of a P2(Y)2
Product or a CFTR Corrector-based product. In any such notification, the
non-publishing party shall indicate with specificity its suggestions regarding
the manner and degree to which the publishing party may disclose such
information. In the case of item (ii) above, the non-publishing party may
request a delay and the publishing party shall delay such publication, for a
period not exceeding an additional [*************], to permit the timely
preparation and filing of a patent application or an application for a
certificate of invention on the information involved. In the case of item (i)
above, no party may publish Confidential Information of the other party without
its consent in violation of Article V of this Agreement. In the case of item
(iii) above, if the publishing party shall disagree with the non-publishing
party's

PORTIONS OF THIS EXHIBIT WERE OMITTED AND HAVE BEEN FILED SEPARATELY WITH THE
SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.

                                     - 24 -
<PAGE>



assessment of the impact of the publication, then the issue shall be referred to
the Chief Executive Officer of CFFT and the Chief Executive Officer of Predix
who shall attempt in good faith to reach a fair and equitable resolution of this
disagreement. If the disagreement is not resolved in this manner within
[*************] of referral to the respective Chief Executive Officers, then the
decision of the publishing party as to publication of any information generated
by it, subject always to the confidentiality provisions of Article V hereof,
shall be final, provided that such decision shall be exercised with reasonable
regard for the interests of the non-publishing party. The Parties agree that
authorship of any publication will be determined based on the customary
standards then being applied in the relevant scientific journal. The Parties
will use their reasonable best efforts to gain the right to review proposed
publications relating to the subject matter of the Research Programs by
consultants or contractors.

      Notwithstanding the foregoing and subject to the last sentence of this
paragraph, Predix intends to advance the body of general scientific knowledge of
CF and its potential therapies, and to contribute to the identification of
chemical tools as optimal scientific benchmarks, all in a manner consistent with
its general scientific and commercial objectives in entering into the
collaboration with CFFT to which this Agreement relates. In furtherance of that
objective, Predix will publish the 3D structure of the CFTR to be developed by
Predix by the [*******************] after the achievement of the second
milestone set forth in Section 3.1.1, or the termination of this Agreement,
whichever occurs first. CFFT's funding of the research will be acknowledged by
the publication; and by the [*************] after the achievement of such second
milestone, Predix shall cause the 3D structure of the CFTR developed by Predix
to become part of the public domain. In addition, Predix shall grant to up to
[******] requesting qualified, not-for-profit research institutions, reasonably
acceptable to Predix, a nonexclusive license to use the 3D structure of the CFTR
solely for research purposes. Such non-exclusive

PORTIONS OF THIS EXHIBIT WERE OMITTED AND HAVE BEEN FILED SEPARATELY WITH THE
SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.

                                     - 25 -
<PAGE>



licenses shall include restrictions on the disclosure of Predix' confidential
information, including without limitation, the structure of the CFTR (if not
previously published by Predix); provided that the licensee shall be permitted
to publish the data, including mutagenesis data, it may generate in the exercise
of the license. Notwithstanding the foregoing publication and licensing
obligations in this paragraph, if at any time such obligations are scheduled to
occur, CFFT has a license pursuant to Section 9.6, CFFT (and not Predix) shall
determine the timing and scope of such publication and the recipients of such
sublicenses with respect to the rights covered by the license granted to CFFT.

                         ARTICLE VII - INDEMNIFICATION

      7.1 INDEMNIFICATION BY PREDIX.

            Predix will indemnify and hold CFFT and its Affiliates, and their
employees, officers and directors harmless against any loss, damage, action,
suit, claim, demand, liability, expense, bodily injury, death or property damage
(a "Loss"), that may be brought, instituted or arise against or be incurred by
such persons to the extent such Loss is based on or arises out of:

                  (a) the conduct of the Research Programs by Predix or its
            Affiliates or their representatives, agents, authorized licensees,
            sublicensees or subcontractors under this Agreement, or any actual
            or alleged violation of law resulting therefrom; or

                  (b) the breach by Predix of any of its covenants,
            representations or warranties set forth in this Agreement; and

                  (c) provided however, that the foregoing indemnification shall
            not apply to any Loss to the extent such Loss is caused by the
            negligent or willful

PORTIONS OF THIS EXHIBIT WERE OMITTED AND HAVE BEEN FILED SEPARATELY WITH THE
SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.

                                     - 26 -
<PAGE>



            misconduct of CFFT or its Affiliates or a breach of this Agreement
            by CFFT or its Affiliates.

      7.2 CLAIMS PROCEDURES.

            In order to be indemnified by Predix, pursuant to Section 7.1, CFFT
shall give notice to Predix promptly after CFFT has actual knowledge of any
threatened or asserted claim as to which indemnity may be sought, and shall
permit Predix to assume the defense of any such claim or any litigation
resulting therefrom; provided:

                  (a) that counsel for Predix, who shall conduct the defense of
            such claim or any litigation resulting therefrom, shall be approved
            by CFFT (the approval of which shall not unreasonably be withheld)
            and CFFT may participate in such defense at its expense, unless (i)
            the employment of counsel by CFFT has been authorized by Predix; or
            (ii) there is a conflict of interest that would prevent Predix and
            CFFT from being represented by a single law firm in the defense of
            such action, in each of which instance Predix shall pay the
            reasonable fees and expenses of one law firm serving as counsel for
            CFFT, which law firm shall be subject to approval, not to be
            unreasonably withheld, by Predix; and

                  (b) the failure of CFFT or its Affiliates to give notice as
            provided herein shall relieve Predix of its obligations under this
            Agreement to the extent that the failure to give notice prejudices a
            defense that otherwise may have been available or increases the
            amount of the Loss or otherwise results in harm to Predix.

                  (c) Predix shall not, in the defense of any such claim or
            litigation, except with the approval of CFFT which approval shall
            not be unreasonably

PORTIONS OF THIS EXHIBIT WERE OMITTED AND HAVE BEEN FILED SEPARATELY WITH THE
SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.

                                     - 27 -
<PAGE>



            withheld, consent to entry of any judgment or enter into any
            settlement which (i) would result in injunctive or other relief
            being imposed against CFFT and its Affiliates; or (ii) does not
            include, as an unconditional term thereof, the giving by the
            claimant or plaintiff to CFFT and its Affiliates of a release from
            all liability in respect to such claim or litigation.

                  (d) CFFT and its Affiliates shall cooperate in the defense of
            such claim as reasonably requested by Predix, including without
            limitation, by furnishing such information regarding itself or the
            claim in question as Predix may reasonably request in writing.

                      ARTICLE VIII - PATENTABLE INVENTIONS

      8.1 OWNERSHIP.

            All inventions made and all data and know-how generated exclusively
by either party or its Affiliates (directly or through others acting on its
behalf) prior to and during the term of this Agreement relating to the Research
Program shall be owned by the party making the invention or generating the data
or know-how claimed, or if such invention is made jointly (a "Joint Invention"),
shall be owned jointly, all as determined in accordance with United States laws
of inventorship; provided that, CFFT hereby grants to Predix an exclusive (even
as to CFFT) worldwide license to its rights in any Joint Invention and any
invention made by a CFFT employee resulting from the Research Program for the
purposes specified in this Agreement.

      8.2 PREPARATION.

PORTIONS OF THIS EXHIBIT WERE OMITTED AND HAVE BEEN FILED SEPARATELY WITH THE
SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.

                                     - 28 -
<PAGE>



            Predix shall take responsibility for the preparation, filing,
prosecution and maintenance of all Predix Patents, and any patents and patent
applications claiming Joint Inventions, and CFFT shall take responsibility for
the preparation, filing, prosecution and maintenance of all CFFT Patents. Predix
shall provide the JRC with periodic reports listing, by name, Patents filed by
Predix in the United States and other jurisdictions, along with a general
summary of the claims made and the jurisdictions of filing.

      8.3 COSTS.

            [*******] shall be responsible for all costs incurred in the
preparation, prosecution and maintenance of [*************] and [*************].

                       ARTICLE IX - TERM AND TERMINATION

      9.1 TERM.

            This Agreement will expire upon the Research Termination Date as
defined herein, unless earlier terminated by either party hereto in accordance
with this Agreement, or unless extended by mutual agreement of the Parties.

      9.2 TERMINATION OF THE RESEARCH PROGRAMS WITHOUT CAUSE.

            CFFT may terminate either or both of the Research Programs without
cause upon one hundred and twenty (120) day's notice.

PORTIONS OF THIS EXHIBIT WERE OMITTED AND HAVE BEEN FILED SEPARATELY WITH THE
SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.

                                     - 29 -
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      9.3 TERMINATION OF THE RESEARCH PROGRAM BY CFFT FOR CAUSE.

            Without limitation of its ability to seek damages for breach of this
Agreement, CFFT may at its sole discretion unilaterally terminate the Research
Program and this Agreement upon the occurrence of any of the following events:

                  (a) Predix shall materially breach any of its material
            obligations under this Agreement, and such material breach shall not
            have been remedied or material steps initiated to remedy the same to
            CFFT's reasonable satisfaction, within thirty (30) days after CFFT
            sends written notice of breach to Predix; or

                  (b) Predix shall cease to function as a going concern by
            suspending or discontinuing its business for any reason except for
            interruptions caused by events of Force Majeure.

            In the event of any valid termination under this Section 9.3, CFFT
shall not be required to make any payments which have not accrued prior to
receipt by Predix of the notice of breach referenced under Section 9.3(a) or
receipt by Predix of the notice of termination pursuant to this Section 9.3(b),
as the case may be.

      9.4 TERMINATION OF THE RESEARCH PROGRAM BY PREDIX FOR CAUSE.

            Without limitation of its ability to seek damages for breach of this
Agreement, Predix may at its sole discretion terminate this Agreement upon
written notice to CFFT upon the occurrence of the following event:

            CFFT shall materially breach any of its material obligations under
this Agreement and such material breach shall not have been remedied or material
steps initiated to remedy the same to Predix's reasonable satisfaction, within
thirty (30) days after Predix sends written notice of breach to CFFT.

PORTIONS OF THIS EXHIBIT WERE OMITTED AND HAVE BEEN FILED SEPARATELY WITH THE
SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.

                                     - 30 -
<PAGE>



      9.5 GENERAL EFFECT OF TERMINATION.

                  (a) The termination of this Agreement for any reason, or
            expiration of this Agreement, will not affect obligations which have
            accrued as of the date of termination or expiration, and obligations
            and rights under the following Sections, each of which shall survive
            any expiration or termination: Sections 2.5.2, 3.1.1 (solely for
            payment for milestones completed within [*****************] of such
            expiration), 3.3, 9.5 and 9.6 and Articles IV, V, VI, VII, VIII, X
            and XI.

                  (b) Subject to Section 4.1 hereof, and subject to the license
            that may be granted under Section 9.6(a), upon termination or
            expiration of this Agreement, Predix will retain ownership or
            exclusive rights to the Predix CF Technology and the inventions
            licensed to it by CFFT pursuant to Section 8.1 of this Agreement
            (including intellectual property rights).

      9.6 CONSEQUENCES OF AN INTERRUPTION.

            Upon the effective date of any Interruption with respect to Research
Program I and/or Research Program II, the following license in favor of CFFT
shall become effective:

                  (a) CFFT shall have an irrevocable, with respect to the
            Research Program to which an Interruption has occurred, exclusive
            (even as to Predix) worldwide license, with the right to sublicense,
            under the Predix CF Technology and Joint Inventions to develop,
            manufacture, have manufactured, use, sell, offer to sell and import
            CFTR Corrector-based products or P2Y(2) Products, as applicable, in
            the Field.

PORTIONS OF THIS EXHIBIT WERE OMITTED AND HAVE BEEN FILED SEPARATELY WITH THE
SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.

                                     - 31 -
<PAGE>



                  (b) In lieu of any research funding obligation owed by CFFT to
            Predix pursuant to this Agreement, except obligations that accrued
            prior to the date of termination and obligations that survive
            termination of this Agreement, CFFT shall pay Predix a
            [*************] royalty on the annual Net Sales of any CFTR
            Corrector-based products discovered or developed using the Predix CF
            Technology or P2Y(2) Products, as applicable, thereafter sold by
            CFFT or any Affiliate, licensee or sublicensee of CFFT, to which the
            foregoing licenses relate.

                  (c) In connection with either or both of the foregoing
            licenses, Predix shall deliver to CFFT, expeditiously upon the
            occurrence of an Interruption, all materials and data generated in
            the performance of Research Program I or Research Program II as
            applicable and the Predix CF Technology, including without
            limitation, the 3D coordinates of the CFTR, that are relevant to
            Research Program I or Research Program II, as applicable.

                   ARTICLE X - REPRESENTATIONS AND WARRANTIES

      10.1 REPRESENTATIONS AND WARRANTIES OF PREDIX.

            Predix represents and warrants to CFFT that this Agreement has been
duly executed and delivered by Predix and constitutes the valid and binding
obligation of Predix, enforceable against Predix in accordance with its terms
except as enforceability may be limited by bankruptcy, fraudulent conveyance,
insolvency, bankruptcy, reorganization, moratorium and other laws relating to or
affecting creditors' rights generally and by general equitable principles. The
execution, delivery and performance of this Agreement have been duly authorized
by all necessary action on the part of Predix, its officers and directors.

      10.2 REPRESENTATIONS AND WARRANTIES OF CFFT.

PORTIONS OF THIS EXHIBIT WERE OMITTED AND HAVE BEEN FILED SEPARATELY WITH THE
SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.

                                     - 32 -
<PAGE>



            CFFT represents and warrants to Predix that this Agreement has been
duly executed and delivered by CFFT and constitutes the valid and binding
obligation of CFFT, enforceable against CFFT in accordance with its terms except
as enforceability may be limited by bankruptcy, fraudulent conveyance,
insolvency, bankruptcy, reorganization, moratorium and other laws relating to or
affecting creditors' rights generally and by general equitable principles. The
execution, delivery and performance of this Agreement have been duly authorized
by all necessary action on the part of CFFT, its officers and directors.

                     ARTICLE XI - MISCELLANEOUS PROVISIONS

      11.1 GOVERNING LAW, AND JURISDICTION.

            This Agreement shall be governed and construed in accordance with
the internal laws of the State of Maryland.

      11.2 WAIVER.

            No provision of this Agreement may be waived except in writing by
both Parties hereto. No failure or delay by either party hereto in exercising
any right or remedy hereunder or under applicable law will operate as a waiver
thereof, or a waiver of any right or remedy on any subsequent occasion.

      11.3 FORCE MAJEURE.

            Neither party will be in breach hereof by reason of its delay in the
performance of or failure to perform any of its obligations hereunder, if that
delay or failure is caused by strikes, acts of God or the public enemy, riots,
incendiaries, interference by civil or military authorities,

PORTIONS OF THIS EXHIBIT WERE OMITTED AND HAVE BEEN FILED SEPARATELY WITH THE
SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.

                                     - 33 -
<PAGE>



compliance with governmental priorities for materials, or any fault beyond its
reasonable control or without its fault or negligence.

      11.4 SEVERABILITY.

            Should one or more provisions of this Agreement be or become
invalid, then the Parties hereto shall attempt to agree upon valid provisions in
substitution for the invalid provisions, which in their economic effect come so
close to the invalid provisions that it can be reasonably assumed that the
Parties would have accepted this Agreement with those new provisions. If the
Parties are unable to agree on such valid provisions, the invalidity of such one
or more provisions of this Agreement shall nevertheless not affect the validity
of the Agreement as a whole, unless the invalid provisions are of such essential
importance for this Agreement that it may be reasonably presumed that the
Parties would not have entered into this Agreement without the invalid
provisions.

      11.5 GOVERNMENT ACTS.

            In the event that any act, regulation, directive, or law of a
country or its government, including its departments, agencies or courts, should
make impossible or prohibit, restrain, modify or limit any material act or
obligation of CFFT or Predix under this Agreement, the party, if any, not so
affected, shall have the right, at its option, to suspend or terminate this
Agreement as to such country, if good faith negotiations between the Parties to
make such modifications therein as may be necessary to fairly address the impact
thereof, are not successful after a reasonable period of time in producing
mutually acceptable modifications to this Agreement.

      11.6 ASSIGNMENT.

PORTIONS OF THIS EXHIBIT WERE OMITTED AND HAVE BEEN FILED SEPARATELY WITH THE
SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.

                                     - 34 -
<PAGE>



            This Agreement may not be assigned or otherwise transferred by
either party without the prior written consent of the other party; provided,
however, that either party may assign this Agreement, without the consent of the
other party, (i) to any of its Affiliates, if the assigning party guarantees the
full performance of its Affiliates' obligations hereunder, or (ii) in connection
with the transfer or sale of all or substantially all of its assets or business
to which this Agreement relates or in the event of its merger or consolidation
with another company. Any purported assignment in contravention of this Section
11.6 shall, at the option of the non-assigning party, be null and void and of no
effect. No assignment shall release either party from responsibility for the
performance of any accrued obligation of such party hereunder. This Agreement
shall be binding upon and enforceable against the successor to or any permitted
assignees from either of the Parties hereto.

      11.7 COUNTERPARTS.

            This Agreement may be executed in duplicate, each of which shall be
deemed to be original and both of which shall constitute one and the same
Agreement.

PORTIONS OF THIS EXHIBIT WERE OMITTED AND HAVE BEEN FILED SEPARATELY WITH THE
SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.

                                     - 35 -
<PAGE>



      11.8 NO AGENCY.

            Nothing herein contained shall be deemed to create an agency, joint
venture, amalgamation, partnership or similar relationship between CFFT and
Predix. Notwithstanding any of the provisions of this Agreement, neither party
to this Agreement shall at any time enter into, incur, or hold itself out to
third parties as having authority to enter into or incur, on behalf of the other
party, any commitment, expense, or liability whatsoever, and all contracts,
expenses and liabilities in connection with or relating to the obligations of
each party under this Agreement shall be made, paid, and undertaken exclusively
by such party on its own behalf and not as an agent or representative of the
other.

      11.9 NOTICE.

            All communications between the Parties with respect to any of the
provisions of this Agreement will be sent to the addresses set out below, or to
such other addresses as may be designated by one party to the other by notice
pursuant hereto, by prepaid, certified air mail (which shall be deemed received
by the other party on the seventh business day following deposit in the mails),
or by facsimile transmission, or other electronic means of communication (which
shall be deemed received when transmitted), with confirmation by first class
letter, postage pre-paid, given by the close of business on or before the next
following business day:

            if to CFFT, at:

               Cystic Fibrosis Foundation Therapeutics Incorporated

               6931 Arlington Road

               Bethesda, Maryland  20814

               Attention:  Dr. Robert J. Beall, President

PORTIONS OF THIS EXHIBIT WERE OMITTED AND HAVE BEEN FILED SEPARATELY WITH THE
SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.

                                     - 36 -
<PAGE>



            with a copy to: Kenneth I. Schaner, Esq.

               Swidler Berlin LLP

               3000 K Street, N.W., Suite 300

               Washington, D.C. 20007

            if to Predix, at:

               Predix Pharmaceuticals Holdings , Inc.

               10K Gill Street

               Woburn, MA  01810

               Attention:  President

               with a copy to: Christopher J. Denn, Esq.

               Mintz, Levin, Cohn, Ferris, Glovsky and Popeo PC

               One Financial Center

               Boston, MA 02111

      11.10 HEADINGS.

            The paragraph headings are for convenience only and will not be
deemed to affect in any way the language of the provisions to which they refer.

      11.11 AUTHORITY.

            The undersigned represent that they are authorized to sign this
Agreement on behalf of the Parties hereto. The Parties each represent that no
provision of this Agreement will

PORTIONS OF THIS EXHIBIT WERE OMITTED AND HAVE BEEN FILED SEPARATELY WITH THE
SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.

                                     - 37 -
<PAGE>



violate any other agreement that such party may have with any other person or
company. Each party has relied on that representation in entering into this
Agreement.

      11.12 ENTIRE AGREEMENT.

            This Agreement contains the entire understanding of the Parties
relating to the matters referred to herein, and may only be amended by a written
document, duly executed on behalf of the respective Parties.

      11.13 NOTICE OF PHARMACEUTICAL SIDE-EFFECTS.

            During the term of this Agreement, the Parties shall keep each other
promptly and fully informed and will promptly notify appropriate authorities in
accordance with applicable law, after receipt of information with respect to any
serious adverse event (as defined by the ICH Harmonized Tripartite Guideline on
Clinical Safety Data Management), directly or indirectly attributable to the use
or application of any P2(Y)2 Product, and any other product for which royalties
are payable under this Agreement.

PORTIONS OF THIS EXHIBIT WERE OMITTED AND HAVE BEEN FILED SEPARATELY WITH THE
SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.

                                     - 38 -
<PAGE>



Agreed and acknowledged as of the Effective Date.

                                  PREDIX PHARMACEUTICALS HOLDINGS, INC.

                                  By: /s/ MICHAEL G. KAUFFMAN, MD
                                      ---------------------------------
                                      Title: President and CEO

                                  CYSTIC FIBROSIS FOUNDATION THERAPEUTICS
                                  INCORPORATED

                                  By: /s/ ROBERT J. BEALL
                                      -----------------------
                                      Title: President and CEO

PORTIONS OF THIS EXHIBIT WERE OMITTED AND HAVE BEEN FILED SEPARATELY WITH THE
SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.

                                     - 39 -
<PAGE>



                                  CONFIDENTIAL

                                   EXHIBIT 2.4

                             CFTR PROGRAM WORK PLAN

     [ * * * * * * * * CFTR Program Work Plan contains confidential material
             and has been omitted in its entirety. * * * * * * * *]

PORTIONS OF THIS EXHIBIT WERE OMITTED AND HAVE BEEN FILED SEPARATELY WITH THE
SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.

<PAGE>



                            P2Y(2) PROGRAM WORK PLAN

     [ * * * * * * * P2Y(2) Program Work Plan contains confidential material
             and has been omitted in its entirety. * * * * * * * *]

PORTIONS OF THIS EXHIBIT WERE OMITTED AND HAVE BEEN FILED SEPARATELY WITH THE
SECRETARY OF THE COMMISSION PURSUANT TO THE COMPANY'S APPLICATION REQUESTING
CONFIDENTIAL TREATMENT UNDER RULE 406 OF THE SECURITIES ACT; [*] DENOTES
OMISSIONS.