Document:

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                                                                     Exhibit 4.3

      THIS WARRANT AND THE SHARES OBTAINABLE UPON ITS EXERCISE HAVE NOT BEEN
      REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR ANY STATE
      SECURITIES LAWS (COLLECTIVELY, THE "ACTS"), AND MAY NOT BE OFFERED, SOLD
      OR OTHERWISE TRANSFERRED, PLEDGED OR HYPOTHECATED UNLESS AND UNTIL
      REGISTERED UNDER ALL APPLICABLE ACTS OR UNLESS AN OPINION OF COUNSEL IS
      DELIVERED TO THE ISSUER IN FORM AND SUBSTANCE SATISFACTORY TO THE ISSUER
      TO THE EFFECT THAT AN EXEMPTION FROM REGISTRATION IS AVAILABLE UNDER ALL
      APPLICABLE ACTS.

No. CS-1                                                        October 30, 2003

                      PREDIX PHARMACEUTICALS HOLDINGS, INC.

                          WARRANT FOR NEW COMMON STOCK

      THIS CERTIFIES THAT, for value received, RRD International, LLC, or its
registered assigns (the "Holder"), is entitled, subject to the vesting
provisions set forth herein, to subscribe for and purchase from Predix
Pharmaceuticals Holdings, Inc., a Delaware corporation (the "Company"), at any
time prior to or upon October 30, 2008, or, in the event such date is a
Saturday, Sunday or United States holiday, the next business day (the
"Expiration Date"), up to one hundred eighty thousand (180,000) shares (the
"Shares") of the Company's New Common Stock, $0.01 par value (the "Common
Stock"), at an exercise price of $1.00 per share (the "Exercise Price").

      This Warrant is subject to the following terms and conditions:

      1. Vesting.

      (a) Upon the terms and subject to the conditions set forth herein, this
Warrant shall vest and Warrants shall be exercisable in five equal installments
upon the execution of this Agreement and the achievement of certain milestones
set forth below in accordance with the following vesting schedule:

            (i) 20% of this Warrant (representing 36,000 Shares) shall vest upon
execution of this Agreement by both parties hereto.

            (ii) 20% of this Warrant (representing 36,000 Shares) shall vest
immediately upon completion of the pre-IND meetings for the Company's PRX-00023
product with the FDA or similar meetings with a foreign equivalent agency;
provided, however, that if such pre-IND meetings or foreign equivalent meetings
are not required, the portion of the Warrant subject to vesting under this
clause (ii) shall vest upon completion of the milestone set forth in clause
(iii) below.

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            (iii) 20% of this Warrant (representing 36,000 Shares) shall vest
immediately upon filing of the IND for the Company's PRX-00023 product with the
FDA or upon an equivalent filing with a foreign agency.

            (iv) 20% of this Warrant (representing 36,000 Shares) shall vest
immediately upon enrollment of the first subject/patient in clinical trials for
the Company's PRX-00023 product.

            (v) 20% of this Warrant (representing 36,000 Shares) shall vest on
July 31, 2004.

Notwithstanding anything herein to the contrary, the milestones set forth above
and the vesting provisions of this Warrant Agreement may be accelerated pursuant
to the provisions of the Master Services Agreement and any Work Orders thereto
entered into between the Company and the Holder of this Warrant as of October
30, 2003.

      2. Exercise; Payment.

      (a) Cash Exercise. The purchase rights represented by this Warrant may be
exercised by the Holder, in whole or in part, at any time, or from time to time,
by the surrender of this Warrant (together with a duly executed notice of
exercise (the "Notice of Exercise") in the form attached hereto as Exhibit A) at
the address of the Company's principal corporate offices set forth in Section 6
hereof, and by payment to the Company of an amount equal to the Exercise Price
multiplied by the number of the Shares being purchased, which amount may be paid
by the Holder by wire transfer or check payable to the order of the Company. The
Person in whose name any certificate representing the Shares issuable upon any
exercise of this Warrant shall be deemed to have become the holder of record of,
and shall be treated for all purposes as the record holder of the Shares
represented thereby (and such Shares shall be deemed to have been issued)
immediately prior to the close of business on the date or dates upon which such
surrender and payment are made. As used herein, the term "Person" means any
individual or any corporation, partnership, trust, limited liability company or
other entity or organization of any kind.

      (b) Stock Certificates. In the event of any exercise of the rights
represented by this Warrant, as promptly as practicable on or after the date of
exercise and in any event within thirty days thereafter, the Company at its
expense shall issue and deliver to the Person or Persons entitled to receive the
same a certificate or certificates representing the number of Shares issued upon
such exercise. In the event that this Warrant is exercised in part, as promptly
as practicable on or after the date of exercise and in any event within thirty
days thereafter, the Company at its sole expense will execute and deliver a new
Warrant of like tenor exercisable for the number of Shares for which this
Warrant may then be exercised.

      (c) Taxes. The issuance of the Shares upon the exercise of this Warrant,
and the delivery of certificates or other instruments representing such Shares,
shall be made

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without charge to the Holder for any tax or other charge of whatever nature in
respect of such issuance and the Company shall bear any such taxes in respect of
such issuance.

      3. Stock Fully Paid; Reservation of Shares. All of the Shares issuable
upon the exercise of the rights represented by this Warrant will, upon issuance
and receipt of the Exercise Price therefor, be fully paid and nonassessable, and
free from all preemptive rights, rights of first refusal or first offer, taxes,
liens and charges of whatever nature, with respect to the issuance thereof.
During the period within which the rights represented by this Warrant may be
exercised, the Company shall use its best efforts, including soliciting its
stockholders for requisite approval, to at all times have authorized and
reserved for issuance a sufficient number of shares of its Common Stock to
provide for the full exercise of the rights represented by this Warrant. In
connection with any amendment to the Company's Certificate of Incorporation (the
"Certificate of Incorporation") to effect the foregoing, the Holder will vote
all shares of the Company's capital stock held by such Holder in favor of such
amendment. The Company hereby agrees that the issuance of this Warrant shall
constitute full authority to its officers who are charged with the duty of
executing stock certificates to execute and issue the proper certificates for
Shares upon the full or each partial exercise of this Warrant and shares of
Common Stock issuable upon any conversion of all or any portion of such Shares.

      4. Adjustment of Exercise Price and Number of Shares. The number and class
or series of Shares purchasable upon the exercise of this Warrant and the
Exercise Price therefor shall be subject to adjustment from time to time upon
the occurrence of certain events, as follows:

      (a) Adjustment for Reclassification, Consolidation or Merger. If while
this Warrant, or any portion hereof, remains outstanding and unexpired there
shall be (i) a reorganization or recapitalization (other than a combination,
reclassification, exchange or subdivision of shares otherwise provided for
herein), (ii) a merger or consolidation of the Company with or into another
Person in which the Company is not the surviving entity, or a reverse merger in
which the Company is the surviving entity but the shares of the Company's
capital stock outstanding immediately prior to the merger are converted by
virtue of the merger into other property, whether in the form of securities,
cash, or otherwise, or (iii) a sale or transfer of the Company's properties and
assets as, or substantially as, an entirety to any other Person in one
transaction or a series of related transactions, then, as a part of such
reorganization, recapitalization, merger, consolidation, sale or transfer,
unless otherwise directed by the Holder, all necessary or appropriate lawful
provisions shall be made so that the Holder shall thereafter be entitled to
receive upon exercise of this Warrant, during the period specified herein and
upon payment of the Exercise Price then in effect, the greatest number of shares
of stock or other securities or property that a holder of the Shares deliverable
upon exercise of this Warrant would have been entitled to receive in such
reorganization, recapitalization, consolidation, merger, sale or transfer if
this Warrant had been exercised immediately prior to such reorganization,
recapitalization, merger, consolidation, sale or transfer, all subject to
further adjustment as provided in this Section 4. If the per Share consideration
payable to the Holder for Shares in connection with any such transaction is in a
form other than cash or marketable securities, then the value of such
consideration shall be

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determined in good faith by the Company's Board of Directors. The foregoing
provisions of this paragraph shall similarly apply to successive
reorganizations, recapitalizations, consolidations, mergers, sales and transfers
and to the stock or securities of any other corporation that are at the time
receivable upon the exercise of this Warrant. In all events, appropriate
adjustment shall be made in the application of the provisions of this Warrant
(including adjustment of the Exercise Price and number of Shares purchasable
pursuant to the terms and conditions of this Warrant) with respect to the rights
and interests of the Holder after the transaction, to the end that the
provisions of this Warrant shall be applicable after that event, as near as
reasonably may be, in relation to any shares or other property deliverable or
issuable after such reorganization, recapitalization, merger, consolidation,
sale or transfer upon exercise of this Warrant.

      (b) Adjustments for Split, Subdivision or Combination of Shares. If the
Company at any time while this Warrant, or any portion hereof, remains
outstanding and unexpired shall split or subdivide any class of securities as to
which purchase rights under this Warrant exist, into a different number of
securities of the same class, the number of shares of such class issuable upon
exercise of this Warrant immediately prior to such split or subdivision shall be
proportionately adjusted and the Exercise Price for such class of securities
shall be proportionately adjusted. If the Company at any time while this
Warrant, or any portion hereof, remains outstanding and unexpired shall combine
any class of securities as to which purchase rights under this Warrant exist,
into a different number of securities of the same class, the number of shares of
such class issuable upon exercise of this Warrant immediately prior to such
combination shall be proportionately adjusted and the Exercise Price for such
class of securities shall be proportionately adjusted.

      (c) Adjustments for Dividends in Stock or Other Securities or Property. If
while this Warrant, or any portion hereof, remains outstanding and unexpired,
the holders of any class of securities as to which purchase rights under this
Warrant exist at the time shall have received, or, on or after the record date
fixed for the determination of eligible stockholders, shall have become entitled
to receive, without payment therefor, other or additional stock or other
securities or property (other than cash) of the Company by way of dividend, then
and in each case, this Warrant shall represent the right to acquire, in addition
to the number of shares of such class of security receivable upon exercise of
this Warrant, and without payment of any additional consideration therefor, the
amount of such other or additional stock or other securities or property (other
than cash) of the Company that such holder would hold on the date of such
exercise had it been the holder of record of the class of security receivable
upon exercise of this Warrant on the date hereof and had thereafter, during the
period from the date hereof to and including the date of such exercise, retained
such shares and/or all other additional stock available by it as aforesaid
during said period, giving effect to all adjustments called for during such
period by the provisions of this Section 4.

      (d) Further Adjustments. In case at any time or from time to time the
Company shall take any action that affects the Shares, other than an action
described herein, then, unless such action will not have a materially adverse
effect upon the rights

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of the Holder, the number of Shares into which this Warrant is exercisable shall
be adjusted in such a manner and at such time as shall be equitable in the
circumstances.

      (e) Notice of Adjustments. Upon any adjustment of the Exercise Price and
any increase or decrease in the number of Shares purchasable upon the exercise
of this Warrant, then, and in each such case, the Company, within 30 days
thereafter, shall give written notice thereof to the Holder at the address of
such Holder as shown on the books of the Company which notice shall state the
Exercise Price as adjusted and, if applicable, the increased or decreased number
of Shares purchasable upon the exercise of this Warrant, setting forth in
reasonable detail the method of calculation of each.

      5. Transfers, etc.

      (a) At any time prior to the Expiration Date, the Warrants shall only be
transferable to Affiliates (as defined below) (each transferee shall be referred
to as a "Permitted Transferee"); and, provided further, that any such transfer
does not increase the total number of holders of Warrants by more than one
(taking into account all prior transfers of any one Warrant) and will not
increase the total number of stockholders of the Company by more than one
(taking into account all prior transfers of any one Warrant). For purposes of
this Warrant, "Affiliate" of a Holder shall mean any of the stockholders,
subsidiaries, officers, directors, members or partners of such Holder, and any
other corporation, partnership or other business entity which directly or
indirectly controls, is controlled by or is under common control with, such
Holder.

      (b) Any transfer pursuant to Section 5(a) shall be effected upon surrender
of this Warrant with a properly executed assignment (in the form attached hereto
as Exhibit B) at the principal office of the Company (or, if another office or
agency has been designated by the Company for such purpose, then at such other
office or agency).

      6. Notices.

      (a) All notices, requests, consents, and other communications under this
Warrant shall be in writing and shall be deemed delivered (i) seven business
days after being sent by registered or certified mail, return receipt requested,
postage prepaid or (ii) three business days after being sent via a reputable
nationwide overnight courier service guaranteeing next business day delivery, in
each case to the intended recipient as set forth below:

      If to the Company, at 10 K Gill Street, Woburn, Massachusetts 01801,
Attention: Chief Financial Officer, or at such other address as may have been
furnished in writing by the Company to the Holder, with a copy to Hale and Dorr
LLP, 650 College Road East, Princeton, New Jersey 08540, Attention: Richard S.
Mattessich, Esq.; or

      If to a Holder, at 11 North Washington Street, Suite 310, Rockville,
Maryland 20850, Attention: Joseph P. Clancy, or at such other address as may be
furnished in writing by the Holder to the Company, with a copy to Curtin, Law,
Roberson, Dunigan & Salans, 900 M Street, NW, Washington, DC 20036, Attn: Thomas
Dunigan, Esq.

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      (b) Either party may give any notice, request, consent or other
communication under this Warrant using any other means (including, without
limitation, personal delivery, messenger service, telecopy, first class mail or
electronic mail), but no such notice, request, consent or other communication
shall be deemed to have been duly given unless and until it is actually received
by the party for whom it is intended. Either party may change the address to
which notices, requests, consents or other communications hereunder are to be
delivered by giving the other party notice in the manner set forth in this
Section.

      7. Legends. Each certificate evidencing the Shares issued upon exercise of
this Warrant, or transfer of such Shares (other than a transfer registered under
the Securities Act, or any subsequent transfer of Shares so registered) shall be
stamped or imprinted with a legend substantially in the following forms:

      THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED
      UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "ACT"), OR THE
      SECURITIES LAWS OF ANY STATE. THE SECURITIES MAY NOT BE TRANSFERRED EXCEPT
      PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT UNDER SUCH ACT AND
      APPLICABLE STATE SECURITIES LAWS OR PURSUANT TO AN APPLICABLE EXEMPTION
      FROM THE REGISTRATION REQUIREMENTS OF SUCH ACT AND SUCH LAWS.

      8. Fractional Shares. No fractional Shares will be issued in connection
with any exercise hereunder. Instead, the Company shall pay to such Holder an
amount in cash equal to any fractional share to which such Holder would be
entitled, multiplied by the Fair Market Value of a Share, as determined in good
faith by the Company's Board of Directors. For purposes of this Section 8, the
Fair Market Value of one Share shall equal: (a) the average of the closing sale
price of the Common Stock (or any other security for which this Warrant is then
exercisable) as quoted on the Nasdaq Stock Market or in the Over-The-Counter
Market Summary or the closing price quoted on any national securities exchange
on which such securities are listed, whichever is applicable, as reported in The
Wall Street Journal for the ten trading days immediately prior to the date of
determination of Fair Market Value (or, if no sales take place on any such
trading day, the average of the closing bid and asked prices on such trading
day); or (b) if the Common Stock (or any other security for which this Warrant
is then exercisable) is not quoted on the Nasdaq Stock Market or
Over-The-Counter or on a national securities exchange, the Fair Market Value of
a Share shall be established in good faith by the Company's Board of Directors.

      9. Representations and Warranties of the Company. The Company hereby
represents and warrants to the Holder as follows:

      (a) This Warrant has been duly authorized and executed by the Company and
is a valid and binding obligation of the Company enforceable in accordance with
its terms;

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      (b) The Company shall use its best efforts to ensure that the Shares have
been duly authorized and reserved for issuance by the Company and, when issued
in accordance with the terms hereof, will be validly issued, fully paid and
nonassessable, and free from all preemptive rights, rights of first refusal or
first offer, taxes, liens and charges of whatever nature; and

      (c) The execution and delivery of this Warrant are not, and the issuance
of the Shares upon exercise of this Warrant in accordance with the terms hereof
will not be, inconsistent with the Company's Certificate of Incorporation, as
then in effect, and the Company's by-laws (the "By-Laws"), as then in effect.

      10. Representations and Warranties by the Holder. The Holder represents
and warrants to the Company as follows:

      (a) This Warrant is being acquired for its own account, for investment and
not with a view to, or for resale in connection with, any distribution thereof
within the meaning of the Securities Act. Upon exercise of this Warrant, the
Holder shall, if so requested by the Company, confirm in writing, in a form
reasonably satisfactory to the Company, that the Shares issuable upon exercise
of this Warrant are being acquired for investment and not with a view toward
distribution or resale that would violate the Securities Act.

      (b) The Holder understands that the Warrant and the Shares have not been
registered under the Securities Act by reason of their issuance in a transaction
exempt from the registration and prospectus delivery requirements of the
Securities Act pursuant to Section 4(2) thereof, and that they must be held by
the Holder indefinitely, and that the Holder must therefore bear the economic
risk of such investment indefinitely, unless a subsequent disposition thereof is
registered under the Securities Act or is exempted from such registration.

      (c) The Holder has such knowledge and experience in financial and business
matters that it is capable of evaluating the merits and risks of the purchase of
this Warrant and the Shares purchasable pursuant to the terms of this Warrant
and of protecting its interests in connection therewith.

      (d) The Holder is able to bear the economic risk of the purchase of the
Shares pursuant to the terms of this Warrant.

      (e) The Holder is an "accredited investor" within the meaning of Rule 501
of Regulation D under the Securities Act.

      11. Rights of Stockholders. Subject to Section 4 hereof, no Holder, as
such, shall be entitled to vote or receive dividends or be deemed the holder of
the Shares or any other securities of the Company that may at any time be
issuable on the exercise hereof for any purpose, nor shall anything contained
herein be construed to confer upon the Holder, as such, any of the rights of a
stockholder of the Company or any right to vote for the election of directors or
upon any matter submitted to stockholders at any meeting thereof, or to give or
withhold consent to any corporate action (whether upon

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any recapitalization, issuance of stock, reclassification of stock, change of
par value, consolidation, merger, conveyance, or otherwise) or to receive notice
of meetings, or to receive dividends or subscription rights or otherwise until
this Warrant shall have been exercised and the Shares purchasable upon the
exercise hereof shall have become issuable, as provided herein.

      12. Expiration of Warrant. This Warrant shall expire and shall no longer
be exercisable as of 5:00 p.m., Eastern Time, on October 30, 2008.

      13. Miscellaneous.

      (a) This Warrant shall be governed by and construed for all purposes under
and in accordance with the laws of the State of Delaware without regard to
principles of conflicts of law.

      (b) The headings in this Warrant are for purposes of reference only, and
shall not limit or otherwise affect any of the terms hereof.

      (c) The representations, warranties, covenants and conditions of the
respective parties contained herein or made pursuant to this Warrant shall
survive the execution and delivery of this Warrant.

      (d) The terms of this Warrant shall be binding upon and shall inure to the
benefit of any successors or assigns of the Company and of the Holder and of the
Shares issued or issuable upon the exercise hereof.

      (e) This Warrant and the other documents delivered pursuant hereto
constitute the full and entire understanding and agreement between the parties
with regard to the subjects hereof and thereof.

      (f) The Company shall not, by amendment of its Certificate of
Incorporation or By-Laws, or through any other means, directly or indirectly,
avoid or seek to avoid the observance or performance of any of the terms of this
Warrant and shall at all times in good faith assist in the carrying out of all
such terms and in the taking of all such action as may be necessary or
appropriate in order to protect the rights of the Holder against impairment.

      (g) Upon receipt of evidence reasonably satisfactory to the Company of the
loss, theft, destruction or mutilation of this Warrant and, in the case of any
such loss, theft or destruction, upon delivery of an indemnity agreement
reasonably satisfactory in form and amount to the Company or, in the case of any
such mutilation, upon surrender and cancellation of such Warrant, the Company,
at its expense, will execute and deliver to the Holder, in lieu thereof, a new
Warrant of like date and tenor.

      (h) This Warrant and any provision hereof may be amended, waived or
terminated only by an instrument in writing signed by the Company and the
Holder.

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      (i) The Warrant Shares shall be registered under the Securities Act to the
extent provided in the certain Registration Rights Agreement, of even date
herewith, by and between the Company and the Holder of this Warrant.

                            [Signature Page Follows]

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      IN WITNESS WHEREOF, the Company has caused this Warrant to be signed by
its duly authorized officer.

                                       Predix Pharmaceuticals Holdings, Inc.

                                       By: /s/ NIK HAYES
                                           ------------------------------------
                                           Name: Nik Hayes
                                           Title: Chief Financial Officer

Acknowledged and Accepted:

RRD INTERNATIONAL, LLC

By: /s/ JOSEPH P. CLANCY
    -------------------------------
Name: Joseph P. Clancy
Title: Chief Executive Officer
Address: 11 North Washington Street, Ste 310
         Rockville, MD 20850

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                                                                       EXHIBIT A

                               NOTICE OF EXERCISE

TO: Predix Pharmaceuticals Holdings, Inc.
    Attention: Chief Financial Officer

      1. The undersigned hereby elects to purchase _________________ shares of
Common Stock of Predix Pharmaceuticals Holdings, Inc. pursuant to the terms of
this Warrant, and tenders herewith payment of the purchase price of such shares
in full.

      2. Please issue a certificate or certificates representing said securities
in the name of the undersigned or in such other name as is specified below:

                              ___________________________
                                        (Name)

                              ___________________________

                              ___________________________
                                       (Address)

      3. The undersigned hereby represents and warrants that the aforesaid
securities are being acquired for the account of the undersigned for investment
and not with a view to, or for resale, in connection with the distribution
thereof, and that the undersigned has no present intention of distributing or
reselling such shares and all representations and warranties of the undersigned
set forth in Section 10 of the attached Warrant are true and correct as of the
date hereof.
                                           ___________________________
                                           (Signature and Date)

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                                                                       EXHIBIT B

                               FORM OF ASSIGNMENT

                  (To be executed by the Holder if such Holder
                        desires to transfer the Warrant)

FOR VALUE RECEIVED __________________________________ (the "Transferor") hereby
sells, assigns and transfers unto _____________________________ (the
"Transferee")

                  (Please print name and address of transferee)

this Warrant, together with all right, title and interest therein, and does
hereby irrevocably constitute and appoint ___________________________ as its
Attorney to transfer such Warrant on the books of Predix Pharmaceuticals
Holdings, Inc., with full power of substitution. The Transferor has provided a
written instrument to the Company notifying the Company of such transfer and
pursuant to which the Transferee hereunder has agreed in writing to be bound by
the terms of the Warrant dated October 30, 2003 issued by Predix Pharmaceuticals
Holdings, Inc., a Delaware corporation, a copy of which has been provided to the
Transferee by the Transferor.

Dated:                                 Signature ______________________________
                                       (Signature must conform in all respects
                                       to name of Holder as specified on the
                                       face of the Warrant)

                                       _________________________________________
                                       (Insert Social Security or other
                                       Identifying Number of Holder)

                                       12<PAGE>

                                                                     Exhibit 4.4

NEITHER THIS WARRANT NOR THE SECURITIES ISSUABLE UPON EXERCISE OF THIS WARRANT
HAVE BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED. NO SALE OR
DISPOSITION MAY BE EFFECTED EXCEPT IN COMPLIANCE WITH RULE 144 UNDER SAID ACT OR
WITHOUT AN EFFECTIVE REGISTRATION STATEMENT RELATED THERETO OR AN OPINION OF
COUNSEL FOR THE HOLDER, SATISFACTORY TO THE COMPANY, THAT SUCH REGISTRATION IS
NOT REQUIRED UNDER THE ACT OR RECEIPT OF A NO-ACTION LETTER FROM THE SECURITIES
AND EXCHANGE COMMISSION.

                       WARRANT TO PURCHASE 4,817 SHARES OF

                      SERIES A CONVERTIBLE PREFERRED STOCK

                                                     January 8, 2004

THIS CERTIFIES THAT, for value received, GENERAL ELECTRIC CAPITAL CORPORATION
("Holder") is entitled to subscribe for and purchase four thousand eight hundred
seventeen (4,817) shares of the fully paid and no assessable Series A
Convertible Preferred Stock (the "Shares" or the "Series A Preferred Stock") of
Predix Pharmaceuticals Holdings, Inc., a Delaware corporation (the "Company"),
at the Warrant Price (as hereinafter defined), pursuant to that certain
equipment lease financing agreement by and between the Holder and the Company
dated December 3, 2002, subject to the provisions and upon the terms and
conditions hereinafter set forth.

1. Warrant Price. The Warrant Price shall initially be Ten and 00/100 dollars
($10.00) per share, subject to adjustment as provided in Section 7 below.

2. Conditions to Exercise. The purchase right represented by this Warrant may be
exercised at any time, or from time to time, in whole or in part during the term
commencing on the date hereof and ending at 5:00 P.M. Pacific time on the tenth
anniversary of the date of this Warrant (the "Expiration Date").

3. Method of Exercise; Payment; Issuance of Shares; Issuance of New Warrant.

      (a) Cash Exercise. Subject to Section 2 hereof, the purchase right
represented by this Warrant may be exercised by the Holder hereof, in whole or
in part, by the surrender of this Warrant (with a duly executed Notice of
Exercise in the form attached hereto) at the principal office of the Company (as
set forth in Section 18 below) and by payment to the Company, by check, of an
amount equal to the then applicable Warrant Price per share multiplied by the
number of shares then being purchased. In the event of any exercise of the
rights represented by this Warrant, certificates for the shares of stock so
purchased shall be in the name of, and delivered to, the Holder hereof, or as
such Holder may direct (subject to the terms of transfer contained herein and
upon payment by such Holder hereof of any applicable transfer taxes). Such
delivery shall be made within 30 days after exercise of the Warrant and at the
Company's expense and, unless this Warrant has been fully exercised or expired,
a new Warrant having terms and conditions substantially identical to this
Warrant and representing the portion of the Shares, if any, with respect to
which this Warrant shall not have been exercised, shall also be issued to the
Holder hereof within 30 days after exercise of the Warrant.

<PAGE>

      (b) Net Issue Exercise. Holder may also elect to receive shares equal to
the value of this Warrant (or of any portion thereof remaining unexercised) by
surrender of this Warrant at the principal office of the Company together with
notice of such election, in which event the Company shall issue to Holder the
number of shares of Series A Preferred Stock computed using the following
formula:

      X = Y (A-B)
          -------
             A

      Where X = the number of shares of Series A Preferred Stock to be issued to
Holder.

      Y = the number of shares of Series A Preferred Stock purchasable under
          this Warrant (at the date of such calculation).

      A = the Fair Market Value of one share of the Series A Preferred Stock (at
          the date of such calculation).

      B = Warrant Price (as adjusted to the date of such calculation).

      (c) Fair Market Value. For purposes of this Section 3, Fair Market Value
of one share of Series A Preferred Stock shall mean:

         (i) The average of the closing bid and asked prices of the Company's
         common stock, $0.01 par value (the "Common Stock") quoted in the
         Over-The-Counter Market Summary, the last reported sale price quoted on
         the Nasdaq National Market or on any exchange on which the Common Stock
         is listed, whichever is applicable, as published in the Western Edition
         of the Wall Street Journal for the ten (10) trading days prior to the
         date of determination of Fair Market Value; or

         (ii) In the event of an exercise in connection with a merger,
         acquisition or other consolidation in which the Company is not the
         surviving entity, the per share Fair Market Value for the Stock shall
         be the value to be received per share of Series A Preferred Stock by
         all holders of the Series A Preferred Stock in such transaction as
         determined by the Board of Directors; or

         (iii) In any other instance, the per share Fair Market Value for the
         Series A Preferred Stock shall be as determined in good faith by the
         Company's Board of Directors.

         In the event of 3(c)(ii) or 3(c)(iii), above, the Company's Board of
         Directors shall prepare a certificate, to be signed by an authorized
         officer of the Company, setting forth in reasonable detail the basis
         for and method of determination of the per share Fair Market Value of
         the Stock. The Board will also certify to the Holder that this per
         share Fair Market Value will be applicable to all holders of the Series

                                       2
<PAGE>

      A Preferred Stock. Such certification must be made to Holder at least
      thirty (30) business days prior to the proposed effective date of the
      merger, consolidation, sale, or other triggering event as defined in
      3(c)(ii) or 3(c)(iii).

   (d) Automatic Exercise. So long as the Fair Market Value of the Warrant is
equal to or greater than the Warrant Price, to the extent this Warrant is not
previously exercised, it shall be automatically exercised in accordance with
Sections 3(b) and 3(c) hereof (even if not surrendered) immediately before its
expiration, involuntary termination or cancellation.

4. Representations and Warranties of Holder and the Company.

   (a) Representations and Warranties by Holder. The Holder represents and
warrants to the Company with respect to his purchase as follows:

      (i) The Holder has substantial experience in evaluating and investing in
      private placement transactions of securities of companies similar to the
      Company so that the Holder is capable of evaluating the merits and risks
      of its investment in the Company and has the capacity to protect its
      interests.

      (ii) Except for transfer to a Holder's affiliates, the Holder is acquiring
      the Warrant and the Shares of Series A Preferred Stock issuable upon
      exercise of the Warrant (collectively the "Securities") for investment for
      its own account and not with a view to, or for resale in connection with,
      any distribution thereof. The Holder understands that the Securities have
      not been registered under the Securities Act of 1933, as amended (the
      "Act") by reason of a specific exemption from the registration provisions
      of the Act which depends upon, among other things, the bona fide nature of
      the investment intent as expressed herein.

      (iii) The Holder acknowledges that the Securities must be held
      indefinitely unless subsequently registered under the Act or an exemption
      from such registration is available. The Holder is aware of the provisions
      of Rule 144 promulgated under the Act.

      (iv) The Holder is an "accredited investor" within the meaning of
      Regulation D promulgated under the Act.

      (v) The Holder has had an opportunity to discuss the Company's business,
      management and financial affairs with its management and an opportunity to
      review the Company's facilities. The Holder understands that such
      discussions, as well as the written information issued by the Company,
      were intended to describe the aspects of the Company's business and
      prospects which the Company believes to be material but were not
      necessarily a thorough or exhaustive description.

   (b) Company hereby represents and warrants to Holder that the statements in
the following paragraphs of this Section 4(b) are true and correct as of the
date hereof.

      (i) Corporate Organization and Authority. The Company (a) is a corporation
      duly organized, validly existing, and in good standing in its jurisdiction
      of

                                       3
<PAGE>

      incorporation, (b) has the corporate power and authority to own and
      operate its properties and to carry on its business as now conducted and
      as proposed to be conducted; and (c) is qualified as a foreign corporation
      in all jurisdictions where the failure to be so qualified would have a
      material adverse effect on the Company.

      (ii) Corporate Power. The Company has all requisite legal and corporate
      power and authority to execute, issue and deliver the Warrant, to issue
      the Series A Preferred Stock issuable upon exercise or conversion of the
      Warrant, and to carry out and perform its obligations under the Warrant
      and any related agreements.

      (iii) Authorization; Enforceability. All corporate action on the part of
      Company, its officers, directors and shareholders necessary for the
      authorization, execution, delivery and performance of its obligations
      under this Warrant and for the authorization, issuance and delivery of the
      Warrant and Stock issuable upon exercise of the Warrant has been taken and
      this Warrant constitutes the legally binding and valid obligation of
      Company enforceable in accordance with its terms.

      (iv) Valid Issuance of Warrant and Series A Preferred Stock. The Warrant
      has been validly issued and is free of restrictions on transfer other than
      restrictions on transfer set forth herein and under applicable state and
      federal securities laws. The Series A Preferred Stock issuable upon
      conversion of this Warrant, when issued, sold and delivered in accordance
      with the terms of this Warrant for the consideration expressed herein,
      will be duly and validly issued, fully paid and no assessable, and will be
      free of restrictions on transfer other than restrictions on transfer under
      this Warrant and under applicable state and federal securities laws.
      Subject to applicable restrictions on transfer, the issuance and delivery
      of the Warrant and the Series A Preferred Stock issuable upon conversion
      of the Warrant are not subject to any preemptive or other similar rights
      or any liens or encumbrances except as specifically set forth in Company's
      Certificate of Incorporation, as amended and restated to date (the
      "Certificate of Incorporation"), or this Warrant. The offer, sale and
      issuance of the Warrant and Series A Preferred Stock, as contemplated by
      this Warrant, are exempt from the prospectus and registration requirements
      of applicable United States federal and state security laws, and neither
      Company nor any authorized agent acting on its behalf has or will take any
      action hereafter that would cause the loss of such exemption.

      (v) No Conflict with Other Instruments. The execution, delivery, and
      performance of this Warrant will not result in any violation of, be in
      conflict with, or constitute a default under, with or without the passage
      of time or the giving of notice (a) any provision of Company's Certificate
      of Incorporation or by-laws; (b) any provision of any judgment, decree, or
      order to which Company is a party or by which it is bound or an event
      which results in the creation of any material lien, charge or encumbrance
      upon any material assets of Company; (c) any

                                       4
<PAGE>

      contract, obligation, or commitment to which Company is a party or by
      which it is bound; or (d) any statute, rule, or governmental regulation
      applicable to Company.

      (vi) Capitalization. As of the date of this Warrant, the authorized and
      issued capital stock of Company is as set forth in Exhibit A. The
      outstanding shares have been duly authorized and validly issued
      (including, without limitation, issued in compliance with applicable
      federal and state securities laws), are fully paid and nonassessable and
      have been issued in compliance with the registration and prospectus
      delivery requirements of the Securities Act and the registration and
      qualification requirements of all applicable state securities laws, or in
      compliance with applicable exemptions therefrom. The Company has reserved
      4,817 shares of Series A Preferred Stock for issuance upon exercise of
      this Warrant and 48,170 shares of Common Stock for the conversion of the
      Series A Preferred Stock to Common Stock. Except as set forth on the
      capitalization table attached to this Warrant in Exhibit A, there are no
      outstanding warrants, options, conversion privileges, preemptive rights or
      other rights or agreements to purchase or otherwise acquire or issue any
      equity securities or convertible securities of Company, nor has the
      issuance of any of the aforesaid rights to acquire securities of Company
      been authorized.

      (vii) Governmental Consents. No consent, approval, order or authorization
      of, or registration, qualification, designation, declaration or filing
      with, any federal, state or local governmental authority on the part of
      Company is required in connection with the offer, sale or issuance of the
      Warrant (and the Stock issuable upon the exercise of this Warrant), or the
      consummation of any other transaction contemplated hereby, except for the
      following: (a) the filing of a notice on Form D under the Act and (b) the
      compliance with other applicable state securities laws, which compliance
      will have occurred within the appropriate time periods therefore. The
      offer, sale and issuance of the Warrant and the shares of Stock in
      conformity with the terms of this Warrant are exempt from the registration
      requirements of the Act and any applicable state laws.

   (c) Within ten (10) days of the Holder providing notice to the Company of its
intent to exercise this Warrant, the Company will deliver to the Holder an
Officer's Certificate certifying that all of the representations and warranties
set forth in this Section 4 are true and correct in all material respects as of
the date of such certificate, except for Section 4(vi), in which case the
Company will deliver to the Holder an updated capitalization table in the same
form as set forth in Appendix A and make the representations and warranties set
forth in Section 4(vi) as they relate to the updated capitalization table.

5. Legends.

   (a) Each certificate representing the Securities shall be endorsed with the
following legend:

   THESE SECURITIES HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933
   AND MAY NOT BE TRANSFERRED UNLESS COVERED BY AN

                                       5
<PAGE>

      EFFECTIVE REGISTRATION STATEMENT UNDER SAID ACT, A "NO ACTION" LETTER FROM
      THE SECURITIES AND EXCHANGE COMMISSION WITH RESPECT TO SUCH TRANSFER, A
      TRANSFER MEETING THE REQUIREMENTS OF RULE 144 OF THE SECURITIES AND
      EXCHANGE COMMISSION, OR (IF REASONABLY REQUIRED BY THE COMPANY) AN OPINION
      OF COUNSEL SATISFACTORY TO THE ISSUER TO THE EFFECT THAT ANY SUCH TRANSFER
      IS EXEMPT FROM SUCH REGISTRATION.

The Company need not enter into its stock records a transfer of Securities
unless the conditions specified in the foregoing legend are satisfied. The
Company may also instruct its transfer agent not to allow the transfer of any of
the Shares unless the conditions specified in the foregoing legends are
satisfied.

      (b) Removal of Legend and Transfer Restrictions. The legend relating to
the Act endorsed on a certificate pursuant to paragraph 5(a) of this Warrant
shall be removed and the Company shall issue a certificate without such legend
to the Holder of the Securities if (i) the Securities are registered under the
Act and a prospectus meeting the requirements of Section 10 of the Act is
available or (ii) the Holder provides to the Company an opinion of counsel for
the Holder reasonably satisfactory to the Company, a no-action letter or
interpretive opinion of the staff of the SEC reasonably satisfactory to the
Company, or other evidence reasonably satisfactory to the Company, to the effect
that public sale, transfer or assignment of the Securities may be made without
registration and without compliance with any restriction such as Rule 144.

6. Condition of Transfer or Exercise of Warrant. It shall be a condition to any
transfer or exercise of this Warrant that at the time of such transfer or
exercise, the Holder shall provide the Company with a representation in writing
that the Holder or transferee is acquiring this Warrant and the shares of Stock
to be issued upon exercise for investment purposes only and not with a view to
any sale or distribution, or will provide the Company with a statement of
pertinent facts covering any proposed distribution. As a further condition to
any transfer of this Warrant or any or all of the shares of Stock issuable upon
exercise of this Warrant, other than a transfer registered under the Act, the
Company may request a legal opinion, in form and substance satisfactory to the
Company and its counsel, reciting the pertinent circumstances surrounding the
proposed transfer and stating that such transfer is exempt from the registration
and prospectus delivery requirements of the Act. The Company shall not require
Holder to provide an opinion of counsel if the transfer is to an affiliate of
Holder. Each certificate evidencing the shares issued upon exercise of the
Warrant or upon any transfer of the shares (other than a transfer registered
under the Act or any subsequent transfer of shares so registered) shall, at the
Company's option, if the Shares are not freely saleable under Rule 144(k) under
the Act, contain a legend in form and substance satisfactory to the Company and
its counsel, restricting the transfer of the shares to sales or other
dispositions exempt from the requirements of the Act. As further condition to
each transfer, at the request of the Company, the Holder shall surrender this
Warrant to the Company and the transferee shall receive and accept a Warrant, of
like tenor and date, executed by the Company.

7. Adjustment for Certain Events. If, and only if, the terms of the Series A
Preferred Stock are not otherwise adjusted in accordance with the Company's
Certificate of Incorporation, the number and kind of securities purchasable upon
the exercise of this Warrant and the Warrant

                                       6
<PAGE>

Price shall be subject to adjustment from time to time upon the occurrence of
certain events, as follows:

      (a) Reclassification or Merger. In case of any reclassification or change
of securities of the class issuable upon exercise of this Warrant (other than a
change in par value, or from par value to no par value, or from no par value to
par value, or as a result of a subdivision or combination), or in case of any
merger of the Company with or into another corporation (other than a merger with
another corporation in which the Company is the acquiring and the surviving
corporation and which does not result in any reclassification or change of
outstanding securities issuable upon exercise of this Warrant), or in case of
any sale of all or substantially all of the assets of the Company, the Company,
or such successor or purchasing corporation, as the case may be, shall duly
execute and deliver to the Holder a new Warrant (in form and substance
satisfactory to the Holder of this Warrant), or the Company shall make
appropriate provision without the issuance of a new Warrant, so that the Holder
shall have the right to receive, at a total purchase price not to exceed that
payable upon the exercise of the unexercised portion of this Warrant, and in
lieu of the shares of Stock theretofore issuable upon exercise of this Warrant,
the kind and amount of shares of stock, other securities, money and property
receivable upon such reclassification, change, merger or sale by a Holder of the
number of shares of Stock then purchasable under this Warrant, or in the case of
such a merger or sale in which the consideration paid consists all or in part of
assets other than securities of the successor or purchasing corporation, at the
option of the Holder, the securities of the successor or purchasing corporation
having a value at the time of the transaction equivalent to the value of the
Stock purchasable upon exercise of this Warrant at the time of the transaction.
Any new Warrant shall provide for adjustments that shall be as nearly equivalent
as may be practicable to the adjustments provided for in this Section 7. The
provisions of this subparagraph (a) shall similarly apply to successive
reclassifications, changes, mergers and transfers.

      (b) Subdivision or Combination of Shares. If the Company at any time while
this Warrant remains outstanding and unexpired shall subdivide or combine its
outstanding shares of Series A Preferred Stock, the Warrant Price shall be
proportionately decreased and the number of Shares issuable hereunder shall be
proportionately increased in the case of a subdivision and the Warrant Price
shall be proportionately increased and the number of Shares issuable hereunder
shall be proportionately decreased in the case of a combination.

      (c) Stock Dividends and Other Distributions. If the Company at any time
while this Warrant is outstanding and unexpired shall (i) pay a dividend with
respect to Series A Preferred Stock payable in any shares of capital stock of
the Company, then the Warrant Price shall be adjusted, from and after the date
of determination of shareholders entitled to receive such dividend or
distribution, to that price determined by multiplying the Warrant Price in
effect immediately prior to such date of determination by a fraction (A) the
numerator of which shall be the total number of shares of Series A Preferred
Stock outstanding immediately prior to such dividend or distribution, and (B)
the denominator of which shall be the total number of shares of Series A
Preferred Stock outstanding immediately after such dividend or distribution; or
(ii) make any other distribution with respect to Series A Preferred Stock
(except any distribution specifically provided for in Sections 7(a) and 7(b)),
then, in each such case, provision shall be made by the Company such that the
Holder of this Warrant shall receive upon exercise of this warrant a
proportionate share of any such dividend or distribution as though it were the
Holder of

                                       7
<PAGE>

the Series A Preferred Stock as of the record date fixed for the determination
of the shareholders of the Company entitled to receive such dividend or
distribution.

      (d) Adjustment of Number of Shares. Upon each adjustment in the Warrant
Price, the number of Shares purchasable hereunder shall be adjusted, to the
nearest whole share, to the product obtained by multiplying the number of Shares
purchasable immediately prior to such adjustment in the Warrant Price by a
fraction, the numerator of which shall be the Warrant Price immediately prior to
such adjustment and the denominator of which shall be the Warrant Price
immediately thereafter.

8. Notice of Adjustments. Whenever any Warrant Price or the kind or number of
securities issuable under this Warrant shall be adjusted pursuant to Section 7
hereof, the Company shall prepare a certificate signed by an officer of the
Company setting forth, in reasonable detail, the event requiring the adjustment,
the amount of the adjustment, the method by which such adjustment was
calculated, and the Warrant Price and number or kind of shares issuable upon
exercise of the Warrant after giving effect to such adjustment, and shall cause
copies of such certificate to be mailed (by certified or registered mail, return
receipt required, postage prepaid) within thirty (30) days of such adjustment to
the Holder of this Warrant as set forth in Section 17 hereof.

9. Transferability of Warrant. (a) This Warrant is transferable on the books of
the Company at its principal office by the registered Holder hereof upon
surrender of this Warrant properly endorsed, subject to compliance with Section
6 hereof and applicable federal and state securities laws. The Company shall
issue and deliver to the transferee a new Warrant representing the Warrant so
transferred. Upon any partial transfer, the Company will issue and deliver to
Holder a new Warrant with respect to the Warrant not so transferred. Holder
shall not have any right to transfer any portion of this Warrant to any direct
competitor of the Company. Notwithstanding the foregoing, although the Warrant
may be transferred more than once, this Warrant shall only be transferable so
long as any such transfer does not increase the total number of holders of this
Warrant by more than one (taking into account all prior transfers of any one
Warrant) and will not increase the total number of stockholders of the Company
by more than one (taking into account all prior transfers of any one Warrant).

      (b) Any transfer pursuant to Section 9(a) shall be effected upon surrender
of this Warrant with a properly executed assignment (in the form attached hereto
as Exhibit B) at the principal office of the Company (or, if another office or
agency has been designated by the Company for such purpose, then at such other
office or agency).

10. Registration Rights.

      (a) Whenever the Company proposes to file a Registration Statement
covering shares of Common Stock (other than a Registration Statement covering
shares: (i) to be sold solely for the account of Other Holders (as defined
below); (ii) pursuant to the initial public offering of the Company; (iii)
pursuant to a Form S-4 or Form S-8, or such similar forms; and (iv) acquired
pursuant to either (A) an acquisition of a company of which they were formerly
stockholders, (B) a "private placement" under the Act or (C) Rule 144A under the
Act) at any time and from time to time, it will, prior to such filing, give
written notice to the Holder of its intention to do so;

                                       8
<PAGE>

provided, that no such notice need be given if none of the Holder's shares of
Common Stock underlying these Securities are to be included therein as a result
of a written notice from the managing underwriter pursuant to Section 10(b)
below. Upon the written request of the Holder given within 20 days after the
Company provides such notice (which request shall state the intended method of
disposition of such shares of Common Stock underlying the Securities), the
Company shall use its commercially reasonable efforts to cause all shares of
Common Stock underlying the Securities which the Company has been requested by
the Holder to register to be registered under the Act to the extent necessary to
permit their sale or other disposition in accordance with the intended methods
of distribution specified in the request of the Holder; provided that the
Company shall have the right to postpone or withdraw any registration effected
pursuant to this Section 10 without obligation to the Holder. For purposes of
this Section 10, "Other Holders" shall mean holders of securities of the Company
(other than the Holder) who are entitled, by contract with the Company, to have
securities included in a Registration Statement pursuant to the terms of that
certain Stockholders Agreement, dated August 8, 2003, by and among the Company
and the Stockholders, as defined therein.

      (b) If the registration for which the Company gives notice pursuant to
Section 10(a) is a registered public offering involving an underwriting, the
Company shall so advise the Holder as a part of the written notice given
pursuant to Section 10(a). In such event, (i) the right of the Holder to include
its Securities in such registration pursuant to this Section 10 shall be
conditioned upon the Holder's participation in such underwriting on the terms
set forth herein and (ii) the Holder including Securities in such registration
shall enter into an underwriting agreement upon customary terms with the
underwriter or underwriters selected for the underwriting by the Company. If the
Holder disapproves of the terms of the underwriting, the Holder may elect, by
written notice to the Company, to withdraw its shares from such Registration
Statement and underwriting. If the managing underwriter advises the Company in
writing that marketing factors require a limitation on the number of shares to
be underwritten, and subject to the superior rights, if any, of the Other
Holders and any other holder of the Company's capital stock then outstanding,
which other holders shall by virtue of such superior rights receive preference
over the Holder (the "Superior Rights Holders"), the shares held by the Holder
shall be excluded from such Registration Statement and underwriting to the
extent deemed advisable by the managing underwriter, and, if a further reduction
of the number of shares is required, and, subject to the rights of Superior
Rights Holders, if any, the number of shares that may be included in such
Registration Statement and underwriting shall be allocated first to the Company,
then to the Other Holders requesting registration in proportion, as nearly as
practicable, to the respective number of shares of Common Stock (on an
as-converted basis) held by them on the date the Company gives the notice
specified in Section 10(a) above, and then to the Holder. If any Holder or Other
Holder would thus be entitled to include more shares than such holder requested
to be registered, the excess shall be allocated among other requesting Holders
and Other Holders pro rata in the manner described in the preceding sentence.

11. No Fractional Shares. No fractional share of Series A Preferred Stock will
be issued in connection with any exercise hereunder, but in lieu of such
fractional share the Company shall make a cash payment therefor upon the basis
of the Warrant Price then in effect.

12. Charges, Taxes and Expenses. Issuance of certificates for shares of Series A
Preferred Stock upon the exercise of this Warrant shall be made without charge
to the Holder for any

                                       9
<PAGE>

United States or state of the United States documentary stamp tax or other
incidental expense with respect to the issuance of such certificate, all of
which taxes and expenses shall be paid by the Company, and such certificates
shall be issued in the name of the Holder.

13. No Shareholder Rights Until Exercise. This Warrant does not entitle the
Holder hereof to any voting rights or other rights as a shareholder of the
Company prior to the exercise hereof.

14. Registry of Warrant. The Company shall maintain a registry showing the name
and address of the registered Holder of this Warrant. This Warrant may be
surrendered for exchange or exercise, in accordance with its terms, at such
office or agency of the Company, and the Company and Holder shall be entitled to
rely in all respects, prior to written notice to the contrary, upon such
registry.

15. Loss, Theft, Destruction or Mutilation of Warrant. Upon receipt by the
Company of evidence reasonably satisfactory to it of the loss, theft,
destruction or mutilation of this Warrant, and, in the case of loss, theft, or
destruction, of indemnity reasonably satisfactory to it, and, if mutilated, upon
surrender and cancellation of this Warrant, the Company will execute and deliver
a new Warrant, having terms and conditions substantially identical to this
Warrant, in lieu hereof.

16. Miscellaneous.

      (a) Issue Date. The provisions of this Warrant shall be construed and
shall be given effect in all respect as if it had been issued and delivered by
the Company on the date hereof.

      (b) Successors. This Warrant shall be binding upon any successors or
assigns of the Company.

      (c) Governing Law. This Warrant shall be governed by and construed in
accordance with the laws of the General Corporation Law of the State of Delaware
as to matters within in the scope thereof, and as to all other matters shall be
governed by and construed in accordance with the internal laws of the
Commonwealth of Massachusetts (without reference to the conflicts of law
provisions thereof).

      (d) Headings. The headings used in this Warrant are used for convenience
only and are not to be considered in construing or interpreting this Warrant.

      (e) Saturdays, Sundays, Holidays. If the last or appointed day for the
taking of any action or the expiration of any right required or granted herein
shall be a Saturday or a Sunday or shall be a legal holiday in the Commonwealth
of Massachusetts, then such action may be taken or such right may be exercised
on the next succeeding day not a legal holiday.

      (f) Waiver of Jury Trial. Each of the parties hereto hereby waives to the
fullest extent permitted by applicable law, any right it may have to a trial by
jury in respect of any litigation directly or indirectly arising out of, under
or in connection with this Warrant or the Shares.

      (g) Attorney's Fees. In the event of any dispute between the parties
concerning the terms and provisions of this Warrant, the party prevailing in
such dispute shall be entitled to

                                       10
<PAGE>

collect from the other party all costs incurred in such dispute, including
reasonable attorney's fees.

17. No Impairment. The Company will not, by amendment of its Certificate of
Incorporation or any other voluntary action, avoid or seek to avoid the
observance or performance of any of the terms of this Warrant, but will at all
times in good faith assist in the carrying out of all such terms and in the
taking of all such action as may be necessary or appropriate in order to protect
the rights of the Holders hereof against impairment.

18. Addresses. Any notice required or permitted hereunder shall be in writing
and shall be mailed by overnight courier, registered or certified mail, return
receipt required, and postage prepaid, or otherwise delivered by hand or by
messenger, addressed as set forth below, or at such other address as the Company
or the Holder hereof shall have furnished to the other party.

                   If to the Company:     Predix Pharmaceuticals Holdings, Inc.
                                          10-K Gill Street
                                          Woburn, MA 01801
                                          Attn: Dr. Michael Kaufmann
                                          Chief Executive Officer

                   If to the Holder:      General Electric Capital Corporation
                                          401 Merritt 7, Suite 23
                                          Norwalk, CT 06851-1177
                                          Attn: Credit Manager

                                       11
<PAGE>

IN WITNESS WHEREOF, the Company has caused this Warrant to be executed by its
officers thereunto duly authorized.

Dated as of January 8, 2004

                                            PREDIX PHARMACEUTICALS
                                            HOLDINGS, INC.

                                            By: /s/ NJG HAYES
                                                ------------------

                                            Name: NJG Hayes

                                            Title: Chief Financial Officer

                                       12
<PAGE>

                               NOTICE OF EXERCISE

TO: Predix Pharmaceuticals Holdings, Inc.
    10-K Gill Street
    Woburn, MA  01801

    The undersigned Warrant holder ("Holder") elects to acquire shares of Series
A convertible preferred stock, $0.01 par value (the "Series A Preferred Stock"),
of Predix Pharmaceuticals Holdings, Inc. (the "Company"), pursuant to the terms
of the Stock Purchase Warrant dated _________, 2004 (the "Warrant").

1.  The Holder exercises its rights under the Warrant as set forth below
   (check one):

            ( )   The Holder elects to purchase ___________ shares of Preferred
                  Stock as provided in Section 3(a) and tenders herewith a
                  check in the amount of $______________ as payment of the
                  purchase price.

            ( )   The Holder elects to convert the purchase rights into shares
                  of Series A Preferred Stock as provided in Section 3(b) of the
                  Warrant.

2.  The Holder surrenders the Warrant with this Notice of Exercise.

The Holder represents that it is acquiring the aforesaid shares of Series A
Preferred Stock for investment and not with a view to or for resale in
connection with distribution and that the Holder has no present intention of
distributing or reselling the shares.

Please issue a certificate representing the shares of the Series A Preferred
Stock in the name of the Holder or in such other name as is specified below:

            Name:
            Address:

            Taxpayer I.D.:

                                       GENERAL ELECTRIC CAPITAL CORPORATION

                                       By:__________________________________

                                       Title:_______________________________

                                       Date:________________________________

<PAGE>

                                                                       EXHIBIT B

                                 ASSIGNMENT FORM

            FOR VALUE RECEIVED, __________________________ hereby sells, assigns
and transfers all of the rights of the undersigned under the attached Warrant
(No.______________) with respect to the number of shares of capital stock of
Predix Pharmaceuticals Holdings, Inc. covered thereby set forth below, unto:

<TABLE>
<CAPTION>
Name of Assignee           Address                         No. of Shares
----------------           -------                         -------------
<S>                        <C>                             <C>
</TABLE>

Dated:______________________________________      Signature:____________________
Signature Guaranteed:
By:_________________________________________

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