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                                                                    Exhibit 10.2

                           SYNTA PHARMACEUTICALS CORP.

                                 2005 STOCK PLAN

1.   DEFINITIONS.

     Unless otherwise specified or unless the context otherwise requires, the
     following terms, as used in this Synta Pharmaceuticals Corp. 2005 Stock
     Plan, have the following meanings:

          ADMINISTRATOR means the Board of Directors, unless it has delegated
          power to act on its behalf to the Committee, in which case the
          Administrator means the Committee.

          AFFILIATE means a corporation which, for purposes of Section 424 of
          the Code, is a parent or subsidiary of the Company, direct or
          indirect.

          AGREEMENT means an agreement between the Company and a Participant
          delivered pursuant to the Plan, in such form as the Administrator
          shall approve.

          BOARD OF DIRECTORS means the Board of Directors of the Company.

          CHANGE OF CONTROL means the occurrence of any of the following events:

                 (i)   Ownership. Any "Person" (as such term is used in Sections
                 13(d) and 14(d) of the Securities Exchange Act of 1934, as
                 amended) becomes the "Beneficial Owner" (as defined in Rule
                 13d-3 under said Act), directly or indirectly, of securities of
                 the Company representing 50% or more of the total voting power
                 represented by the Company's then outstanding voting securities
                 (excluding for this purpose any such voting securities held by
                 the Company or its Affiliates or by any employee benefit plan
                 of the Company) pursuant to a transaction or a series of
                 related transactions which the Board of Directors does not
                 approve; or

                 (ii)   Merger/Sale of Assets. (A) A merger or consolidation of
                 the Company whether or not approved by the Board of Directors,
                 other than a merger or consolidation which would result in the
                 voting securities of the Company outstanding immediately prior
                 thereto continuing to represent (either by remaining
                 outstanding or by being converted into voting securities of the
                 surviving entity or the parent of such corporation) at least
                 50% of the total voting power represented by the voting
                 securities of the Company or such surviving entity or parent of
                 such corporation, as the case may be, outstanding immediately
                 after such merger or consolidation; (B) or the stockholders of
                 the Company approve an agreement for the sale

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                 or disposition by the Company of all or substantially all of
                 the Company's assets; or

          (iii)  Change in Board Composition. A change in the composition of the
                 Board of Directors, as a result of which fewer than a majority
                 of the directors are Incumbent Directors. "Incumbent Directors"
                 shall mean directors who either (A) are directors of the
                 Company as of January 11, 2005, or (B) are elected, or
                 nominated for election, to the Board of Directors with the
                 affirmative votes of at least a majority of the Incumbent
                 Directors at the time of such election or nomination (but shall
                 not include an individual whose election or nomination is in
                 connection with an actual or threatened proxy contest relating
                 to the election of directors to the Company).

          CODE means the United States Internal Revenue Code of 1986, as
          amended.

          COMMITTEE means the committee of the Board of Directors to which the
          Board of Directors has delegated power to act under or pursuant to the
          provisions of the Plan.

          COMMON STOCK means shares of the Company's common stock, $.0001 par
          value per share.

          COMPANY means Synta Pharmaceuticals Corp., a Delaware corporation.

          DISABILITY or DISABLED means permanent and total disability as defined
          in Section 22(e)(3) of the Code.

          EMPLOYEE means any employee of the Company or of an Affiliate
          (including, without limitation, an employee who is also serving as an
          officer or director of the Company or of an Affiliate), designated by
          the Administrator to be eligible to be granted one or more Stock
          Rights under the Plan.

          FAIR MARKET VALUE of a Share of Common Stock means:

          (1)    If the Common Stock is listed on a national securities exchange
          or traded in the over-the-counter market and sales prices are
          regularly reported for the Common Stock, the closing or last price of
          the Common Stock on the composite tape or other comparable reporting
          system for the trading day immediately preceding the applicable date;

          (2)    If the Common Stock is not traded on a national securities
          exchange but is traded on the over-the-counter market, if sales prices
          are not regularly reported for the Common Stock for the trading day
          referred to in clause (1), and if bid and asked prices for the Common
          Stock are regularly reported, the mean between the bid and the asked
          price for the Common Stock at the close of trading in the

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          over-the-counter market for the trading day on which Common Stock was
          traded immediately preceding the applicable date; and

          (3)    If the Common Stock is neither listed on a national securities
          exchange nor traded in the over-the-counter market, such value as the
          Administrator, in good faith, shall determine.

          ISO means an option meant to qualify as an incentive stock option
          under Section 422 of the Code.

          NON-QUALIFIED OPTION means an option which is not intended to qualify
          as an ISO.

          OPTION means an ISO or Non-Qualified Option granted under the Plan.

          PARTICIPANT means an Employee, director or consultant of the Company
          or an Affiliate to whom one or more Stock Rights are granted under the
          Plan. As used herein, "Participant" shall include "Participant's
          Survivors" where the context requires.

          PLAN means this Synta Pharmaceuticals Corp. 2005 Stock Plan.

          SHARES means shares of the Common Stock as to which Stock Rights have
          been or may be granted under the Plan or any shares of capital stock
          into which the Shares are changed or for which they are exchanged
          within the provisions of Paragraph 3 of the Plan. The Shares issued
          under the Plan may be authorized and unissued shares or shares held by
          the Company in its treasury, or both.

          STOCK-BASED AWARD means a grant by the Company under the Plan of an
          equity award or equity based award which is not an Option or Stock
          Grant.

          STOCK GRANT means a grant by the Company of Shares under the Plan.

          STOCK RIGHT means a right to Shares or the value of Shares of the
          Company granted pursuant to the Plan -- an ISO, a Non-Qualified
          Option, a Stock Grant or a Stock-Based Award.

          SURVIVOR means a deceased Participant's legal representatives and/or
          any person or persons who acquired the Participant's rights to a Stock
          Right by will or by the laws of descent and distribution.

2.   PURPOSES OF THE PLAN.

     The Plan is intended to encourage ownership of Shares by Employees and
directors of and certain consultants to the Company in order to attract such
people, to induce them to work for the benefit of the Company or of an Affiliate
and to provide additional incentive for them to

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promote the success of the Company or of an Affiliate. The Plan provides for the
granting of ISOs, Non-Qualified Options, Stock Grants and Stock-Based Awards.

3.   SHARES SUBJECT TO THE PLAN.

     (a)  The number of Shares which may be issued from time to time pursuant to
this Plan, shall be 3,500,000, or the equivalent of such number of Shares after
the Administrator, in its sole discretion, has interpreted the effect of any
stock split, stock dividend, combination, recapitalization or similar
transaction in accordance with Paragraph 24 of the Plan.

     (b)  If an Option ceases to be outstanding, in whole or in part (other than
by exercise), or if the Company shall reacquire (at no more than its original
issuance price) any Shares issued pursuant to a Stock Grant or Stock-Based
Award, or if any Stock Right expires or is forfeited, cancelled, or otherwise
terminated or results in any Shares not being issued, the unissued Shares which
were subject to such Stock Right shall again be available for issuance from time
to time pursuant to this Plan.

     (c)  Notwithstanding Subparagraph (a) above, on the first day of each
fiscal year of the Company during the period beginning in fiscal year 2006, and
ending on the second day of fiscal year 2014, the number of Shares that may be
issued from time to time pursuant to the Plan, shall be increased by an amount
equal to the lesser of (i) 1,900,000 or the equivalent of such number of Shares
after the Administrator, in its sole discretion, has interpreted the effect of
any stock split, stock dividend, combination, recapitalization or similar
transaction in accordance with Paragraph 24 of the Plan; (ii) 5% of the number
of outstanding shares of Common Stock on such date; and (iii) an amount
determined by the Board. However, in no event shall the number of Shares
available for issuance under this Plan be increased as set forth in this
Subparagraph (c) to the extent such increase, in addition to any other increases
proposed by the Board in the number of shares of Common Stock available for
issuance under all other employee or director stock plans, including, without
limitation, employee stock purchase plans, would result in the total number of
shares of Common Stock then available for issuance under all employee and
director stock plans exceeding 25% of the outstanding shares of the Company on
the first day of the applicable fiscal year.

     4.   ADMINISTRATION OF THE PLAN.

     The Administrator of the Plan will be the Board of Directors, except to the
extent the Board of Directors delegates its authority to the Committee, in which
case the Committee shall be the Administrator. Subject to the provisions of the
Plan, the Administrator is authorized to:

     a.   Interpret the provisions of the Plan and all Stock Rights and to make
          all rules and determinations which it deems necessary or advisable for
          the administration of the Plan;

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     b.   Determine which Employees, directors and consultants shall be granted
          Stock Rights;

     c.   Determine the number of Shares for which a Stock Right or Stock Rights
          shall be granted; provided, however, that in no event shall Stock
          Rights with respect to more than 175,000 Shares be granted to any
          Participant in any fiscal year;

     d.   Specify the terms and conditions upon which a Stock Right or Stock
          Rights may be granted;

     e.   to make changes to any outstanding Stock Right, including, without
          limitation, to reduce or increase the exercise price or purchase
          price, to accelerate the vesting schedule or to extend the expiration
          date, provided that no such change shall impair the rights of a
          Participant under any grant previously made without such Participant's
          consent;

     f.   to buy out for a payment in cash or Shares, a Stock Right previously
          granted and/or to cancel any such Stock Right and grant in
          substitution therefor other Stock Rights, covering the same or a
          different numbers of Shares and having an exercise price or purchase
          price per share which may be lower or higher than the exercise price
          or purchase price of the cancelled Stock Right, based on such terms
          and conditions as the Administrator shall establish and the
          Participant shall accept; and

     g.   Adopt any sub-plans applicable to residents of any specified
          jurisdiction as it deems necessary or appropriate in order to comply
          with or take advantage of any tax or other laws applicable to the
          Company or to Plan Participants or to otherwise facilitate the
          administration of the Plan, which sub-plans may include additional
          restrictions or conditions applicable to Stock Rights or Shares
          issuable pursuant to a Stock Right;

provided, however, that all such interpretations, rules, determinations, terms
and conditions shall be made and prescribed in the context of preserving the tax
status under Section 422 of the Code of those Options which are designated as
ISOs. Subject to the foregoing, the interpretation and construction by the
Administrator of any provisions of the Plan or of any Stock Right granted under
it shall be final, unless otherwise determined by the Board of Directors, if the
Administrator is the Committee. In addition, if the Administrator is the
Committee, the Board of Directors may take any action under the Plan that would
otherwise be the responsibility of the Committee.

     To the extent permitted under applicable law, the Board of Directors or the
Committee may allocate all or any portion of its responsibilities and powers to
any one or more of its members and may delegate all or any portion of its
responsibilities and powers to any other person selected by it. Any such
allocation or delegation may be revoked by the Board of Directors or the
Committee at any time.

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5.   ELIGIBILITY FOR PARTICIPATION.

     The Administrator will, in its sole discretion, name the Participants in
the Plan, provided, however, that each Participant must be an Employee, director
or consultant of the Company or of an Affiliate at the time a Stock Right is
granted. Notwithstanding the foregoing, the Administrator may authorize the
grant of a Stock Right to a person not then an Employee, director or consultant
of the Company or of an Affiliate; provided, however, that the actual grant of
such Stock Right shall be conditioned upon such person becoming eligible to
become a Participant at or prior to the time of the execution of the Agreement
evidencing such Stock Right. ISOs may be granted only to Employees.
Non-Qualified Options, Stock Grants and Stock-Based Awards may be granted to any
Employee, director or consultant of the Company or an Affiliate. The granting of
any Stock Right to any individual shall neither entitle that individual to, nor
disqualify him or her from, participation in any other grant of Stock Rights.

6.   TERMS AND CONDITIONS OF OPTIONS.

     Each Option shall be set forth in writing in an Option Agreement, duly
executed by the Company and, to the extent required by law or requested by the
Company, by the Participant. The Administrator may provide that Options be
granted subject to such terms and conditions, consistent with the terms and
conditions specifically required under this Plan, as the Administrator may deem
appropriate including, without limitation, subsequent approval by the
shareholders of the Company of this Plan or any amendments thereto. The Option
Agreements shall be subject to at least the following terms and conditions:

     A.   NON-QUALIFIED OPTIONS: Each Option intended to be a Non-Qualified
          Option shall be subject to the terms and conditions which the
          Administrator determines to be appropriate and in the best interest of
          the Company, subject to the following minimum standards for any such
          Non-Qualified Option:

          a.     OPTION PRICE: Each Option Agreement shall state the option
                 price (per share) of the Shares covered by each Option, which
                 option price shall be determined by the Administrator but shall
                 not be less than the Fair Market Value per share of Common
                 Stock.

          b.     NUMBER OF SHARES: Each Option Agreement shall state the number
                 of Shares to which it pertains.

          c.     OPTION PERIODS: Each Option Agreement shall state the date or
                 dates on which it first is exercisable and the date after which
                 it may no longer be exercised, and may provide that the Option
                 rights accrue or become exercisable in installments over a
                 period of months or years, or upon the occurrence of certain
                 conditions or the attainment of stated goals or events.

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          d.     OPTION CONDITIONS: Exercise of any Option may be conditioned
                 upon the Participant's execution of a Share purchase agreement
                 in form satisfactory to the Administrator providing for certain
                 protections for the Company and its other shareholders,
                 including requirements that:

                 i.   The Participant's or the Participant's Survivors' right to
                      sell or transfer the Shares may be restricted; and

                 ii.  The Participant or the Participant's Survivors may be
                      required to execute letters of investment intent and must
                      also acknowledge that the Shares will bear legends noting
                      any applicable restrictions.

     B.   ISOs: Each Option intended to be an ISO shall be issued only to an
          Employee and be subject to the following terms and conditions, with
          such additional restrictions or changes as the Administrator
          determines are appropriate but not in conflict with Section 422 of the
          Code and relevant regulations and rulings of the Internal Revenue
          Service:

          a.     MINIMUM STANDARDS: The ISO shall meet the minimum standards
                 required of Non-Qualified Options, as described in Paragraph
                 6(A) above, except clause (a) thereunder.

          b.     OPTION PRICE: Immediately before the ISO is granted, if the
                 Participant owns, directly or by reason of the applicable
                 attribution rules in Section 424(d) of the Code:

                 i.   Ten percent (10%) OR LESS of the total combined voting
                      power of all classes of stock of the Company or an
                      Affiliate, the Option price per share of the Shares
                      covered by each ISO shall not be less than one hundred
                      percent (100%) of the Fair Market Value per share of the
                      Shares on the date of the grant of the Option; or

                 ii.  More than ten percent (10%) of the total combined voting
                      power of all classes of stock of the Company or an
                      Affiliate, the Option price per share of the Shares
                      covered by each ISO shall not be less than one hundred ten
                      percent (110%) of the Fair Market Value on the date of
                      grant.

          c.     TERM OF OPTION: For Participants who own:

                 i.   Ten percent (10%) OR LESS of the total combined voting
                      power of all classes of stock of the Company or an
                      Affiliate, each ISO shall terminate not more than ten (10)
                      years from the date of the grant or at such earlier time
                      as the Option Agreement may provide; or

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                 ii.  More than ten percent (10%) of the total combined voting
                      power of all classes of stock of the Company or an
                      Affiliate, each ISO shall terminate not more than five (5)
                      years from the date of the grant or at such earlier time
                      as the Option Agreement may provide.

          d.     LIMITATION ON YEARLY EXERCISE: The Option Agreements shall
                 restrict the amount of ISOs which may become exercisable in any
                 calendar year (under this or any other ISO plan of the Company
                 or an Affiliate) so that the aggregate Fair Market Value
                 (determined at the time each ISO is granted) of the stock with
                 respect to which ISOs are exercisable for the first time by the
                 Participant in any calendar year does not exceed $100,000.

7.   TERMS AND CONDITIONS OF STOCK GRANTS.

     Each offer of a Stock Grant to a Participant shall state the date prior to
which the Stock Grant must be accepted by the Participant, and the principal
terms of each Stock Grant shall be set forth in an Agreement, duly executed by
the Company and, to the extent required by law or requested by the Company, by
the Participant. The Agreement shall be in a form approved by the Administrator
and shall contain terms and conditions which the Administrator determines to be
appropriate and in the best interest of the Company, subject to the following
minimum standards:

     (a)  Each Agreement shall state the purchase price (per share), if any, of
          the Shares covered by each Stock Grant, which purchase price shall be
          determined by the Administrator but shall not be less than the minimum
          consideration required by the Delaware General Corporation Law on the
          date of the grant of the Stock Grant;

     (b)  Each Agreement shall state the number of Shares to which the Stock
          Grant pertains; and

     (c)  Each Agreement shall include the terms of any right of the Company to
          restrict or reacquire the Shares subject to the Stock Grant, including
          the time and events upon which such rights shall accrue and the
          purchase price therefor, if any.

8.   TERMS AND CONDITIONS OF OTHER STOCK-BASED AWARDS.

     The Board shall have the right to grant other Stock-Based Awards based upon
the Common Stock having such terms and conditions as the Board may determine,
including, without limitation, the grant of Shares based upon certain
conditions, the grant of securities convertible into Shares and the grant of
stock appreciation rights, phantom stock awards or stock units. The principal
terms of each Stock-Based Award shall be set forth in an Agreement, duly
executed by the Company and, to the extent required by law or requested by the
Company, by

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the Participant. The Agreement shall be in a form approved by the Administrator
and shall contain terms and conditions which the Administrator determines to be
appropriate and in the best interest of the Company.

9.   EXERCISE OF OPTIONS AND ISSUE OF SHARES.

     An Option (or any part or installment thereof) shall be exercised by giving
written notice to the Company or its designee, together with provision for
payment of the full purchase price in accordance with this Paragraph for the
Shares as to which the Option is being exercised, and upon compliance with any
other condition(s) set forth in the Option Agreement. Such notice shall be
signed by the person exercising the Option, shall state the number of Shares
with respect to which the Option is being exercised and shall contain any
representation required by the Plan or the Option Agreement. Payment of the
purchase price for the Shares as to which such Option is being exercised shall
be made (a) in United States dollars in cash or by check, or (b) at the
discretion of the Administrator, through delivery of shares of Common Stock
having a Fair Market Value equal as of the date of the exercise to the cash
exercise price of the Option, or (c) at the discretion of the Administrator, by
having the Company retain from the shares otherwise issuable upon exercise of
the Option, a number of shares having a Fair Market Value equal as of the date
of exercise to the exercise price of the Option, or (d) at the discretion of the
Administrator, by delivery of the grantee's personal recourse note bearing
interest payable not less than annually at no less than 100% of the applicable
Federal rate, as defined in Section 1274(d) of the Code, or (e) at the
discretion of the Administrator, in accordance with a cashless exercise program
established with a securities brokerage firm, and approved by the Administrator,
or (f) at the discretion of the Administrator, by any combination of (a), (b),
(c), (d) and (e) above, or (g) at the discretion of the Administrator, payment
of such other lawful consideration as the Board may determine. Notwithstanding
the foregoing, the Administrator shall accept only such payment on exercise of
an ISO as is permitted by Section 422 of the Code.

     The Company shall then reasonably promptly deliver the Shares as to which
such Option was exercised to the Participant (or to the Participant's Survivors,
as the case may be). In determining what constitutes "reasonably promptly," it
is expressly understood that the issuance and delivery of the Shares may be
delayed by the Company in order to comply with any law or regulation (including,
without limitation, state securities or "blue sky" laws) which requires the
Company to take any action with respect to the Shares prior to their issuance.
The Shares shall, upon delivery, be fully paid, non-assessable Shares.

     The Administrator shall have the right to accelerate the date of exercise
of any installment of any Option; provided that the Administrator shall not
accelerate the exercise date of any installment of any Option granted to an
Employee as an ISO (and not previously converted into a Non-Qualified Option
pursuant to Paragraph 27) if such acceleration would violate the annual vesting
limitation contained in Section 422(d) of the Code, as described in Paragraph
6.B.d.

     The Administrator may, in its discretion, amend any term or condition of an
outstanding Option provided (i) such term or condition as amended is permitted
by the Plan, (ii) any such

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amendment shall be made only with the consent of the Participant to whom the
Option was granted, or in the event of the death of the Participant, the
Participant's Survivors, if the amendment is adverse to the Participant, and
(iii) any such amendment of any ISO shall be made only after the Administrator
determines whether such amendment would constitute a "modification" of any
Option which is an ISO (as that term is defined in Section 424(h) of the Code)
or would cause any adverse tax consequences for the holder of such ISO.

10.  ACCEPTANCE OF STOCK GRANTS AND STOCK-BASED AWARDS AND ISSUE OF SHARES.

     A Stock Grant or Stock-Based Award (or any part or installment thereof)
shall be accepted by executing the applicable Agreement and delivering it to the
Company or its designee, together with provision for payment of the full
purchase price, if any, in accordance with this Paragraph for the Shares as to
which such Stock Grant or Stock-Based Award is being accepted, and upon
compliance with any other conditions set forth in the applicable Agreement.
Payment of the purchase price for the Shares as to which such Stock Grant or
Stock-Based Award is being accepted shall be made (a) in United States dollars
in cash or by check, or (b) at the discretion of the Administrator, through
delivery of shares of Common Stock having a Fair Market Value equal as of the
date of acceptance of the Stock Grant or Stock-Based Award to the purchase price
of the Stock Grant or Stock-Based Award, or (c) at the discretion of the
Administrator, by delivery of the grantee's personal recourse note bearing
interest payable not less than annually at no less than 100% of the applicable
Federal rate, as defined in Section 1274(d) of the Code, or (d) at the
discretion of the Administrator, by any combination of (a), (b) and (c) above.

     The Company shall then, if required pursuant to the applicable Agreement,
reasonably promptly deliver the Shares as to which such Stock Grant or
Stock-Based Award was accepted to the Participant (or to the Participant's
Survivors, as the case may be), subject to any escrow provision set forth in the
applicable Agreement. In determining what constitutes "reasonably promptly," it
is expressly understood that the issuance and delivery of the Shares may be
delayed by the Company in order to comply with any law or regulation (including,
without limitation, state securities or "blue sky" laws) which requires the
Company to take any action with respect to the Shares prior to their issuance.

     The Administrator may, in its discretion, amend any term or condition of an
outstanding Stock Grant, Stock-Based Award or applicable Agreement provided (i)
such term or condition as amended is permitted by the Plan, and (ii) any such
amendment shall be made only with the consent of the Participant to whom the
Stock Grant or Stock-Based Award was made, if the amendment is adverse to the
Participant.

11.  RIGHTS AS A SHAREHOLDER.

     No Participant to whom a Stock Right has been granted shall have rights as
a shareholder with respect to any Shares covered by such Stock Right, except
after due exercise of the Option

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or acceptance of the Stock Grant or as set forth in any Agreement and tender of
the full purchase price, if any, for the Shares being purchased pursuant to such
exercise or acceptance and registration of the Shares in the Company's share
register in the name of the Participant.

12.  ASSIGNABILITY AND TRANSFERABILITY OF STOCK RIGHTS.

     By its terms, a Stock Right granted to a Participant shall not be
transferable by the Participant other than (i) by will or by the laws of descent
and distribution, or (ii) as approved by the Administrator in its discretion and
set forth in the applicable Agreement. Notwithstanding the foregoing, an ISO
transferred except in compliance with clause (i) above shall no longer qualify
as an ISO. The designation of a beneficiary of a Stock Right by a Participant,
with the prior approval of the Administrator and in such form as the
Administrator shall prescribe, shall not be deemed a transfer prohibited by this
Paragraph. Except as provided above, a Stock Right shall only be exercisable or
may only be accepted, during the Participant's lifetime, by such Participant (or
by his or her legal representative) and shall not be assigned, pledged or
hypothecated in any way (whether by operation of law or otherwise) and shall not
be subject to execution, attachment or similar process. Any attempted transfer,
assignment, pledge, hypothecation or other disposition of any Stock Right or of
any rights granted thereunder contrary to the provisions of this Plan, or the
levy of any attachment or similar process upon a Stock Right, shall be null and
void.

13.  EFFECT ON OPTIONS OF TERMINATION OF SERVICE OTHER THAN "FOR CAUSE" OR DEATH
     OR DISABILITY.

     Except as otherwise provided in a Participant's Option Agreement in the
event of a termination of service (whether as an employee, director or
consultant) with the Company or an Affiliate before the Participant has
exercised an Option, the following rules apply:

     a.   A Participant who ceases to be an employee, director or consultant of
          the Company or of an Affiliate (for any reason other than termination
          "for cause", Disability, or death for which events there are special
          rules in Paragraphs 14, 15, and 16, respectively), may exercise any
          Option granted to him or her to the extent that the Option is
          exercisable on the date of such termination of service, but only
          within such term as the Administrator has designated in a
          Participant's Option Agreement.

     b.   Except as provided in Subparagraph (c) below, or Paragraph 15 or 16,
          in no event may an Option intended to be an ISO, be exercised later
          than three (3) months after the Participant's termination of
          employment.

     c.   The provisions of this Paragraph, and not the provisions of Paragraph
          15 or 16, shall apply to a Participant who subsequently becomes
          Disabled or dies after the termination of employment, director status
          or consultancy; provided, however, in the case of a Participant's
          Disability or death within three (3) months after the

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          termination of employment, director status or consultancy, the
          Participant or the Participant's Survivors may exercise the Option
          within one (1) year after the date of the Participant's termination of
          service, but in no event after the date of expiration of the term of
          the Option.

     d.   Notwithstanding anything herein to the contrary, if subsequent to a
          Participant's termination of employment, termination of director
          status or termination of consultancy, but prior to the exercise of an
          Option, the Board of Directors determines that, either prior or
          subsequent to the Participant's termination, the Participant engaged
          in conduct which would constitute "cause", then such Participant shall
          forthwith cease to have any right to exercise any Option.

     e.   A Participant to whom an Option has been granted under the Plan who is
          absent from the Company or an Affiliate because of temporary
          disability (any disability other than a Disability as defined in
          Paragraph 1 hereof), or who is on leave of absence for any purpose,
          shall not, during the period of any such absence, be deemed, by virtue
          of such absence alone, to have terminated such Participant's
          employment, director status or consultancy with the Company or with an
          Affiliate, except as the Administrator may otherwise expressly
          provide.

     f.   Except as required by law or as set forth in a Participant's Option
          Agreement, Options granted under the Plan shall not be affected by any
          change of a Participant's status within or among the Company and any
          Affiliates, so long as the Participant continues to be an employee,
          director or consultant of the Company or any Affiliate.

14.  EFFECT ON OPTIONS OF TERMINATION OF SERVICE "FOR CAUSE".

     Except as otherwise provided in a Participant's Option Agreement, the
following rules apply if the Participant's service (whether as an employee,
director or consultant) with the Company or an Affiliate is terminated "for
cause" prior to the time that all his or her outstanding Options have been
exercised:

     a.   All outstanding and unexercised Options as of the time the Participant
          is notified his or her service is terminated "for cause" will
          immediately be forfeited.

     b.   For purposes of this Plan, "cause" shall include (and is not limited
          to) dishonesty with respect to the Company or any Affiliate,
          insubordination, substantial malfeasance or non-feasance of duty,
          unauthorized disclosure of confidential information, breach by the
          Participant of any provision of any employment, consulting, advisory,
          nondisclosure, inventions assignment, non-competition or similar
          agreement between the Participant and the Company, and conduct
          substantially prejudicial to the business of the Company or any
          Affiliate. The determination of the Administrator as to the existence
          of "cause" will be conclusive on the Participant and the Company.

                                       12
<Page>

     c.   "Cause" is not limited to events which have occurred prior to a
          Participant's termination of service, nor is it necessary that the
          Administrator's finding of "cause" occur prior to termination. If the
          Administrator determines, subsequent to a Participant's termination of
          service but prior to the exercise of an Option, that either prior or
          subsequent to the Participant's termination the Participant engaged in
          conduct which would constitute "cause", then the right to exercise any
          Option is forfeited.

     d.   Any provision in an agreement between the Participant and the Company
          or an Affiliate, which contains a conflicting definition of "cause"
          for termination and which is in effect at the time of such
          termination, shall supersede the definition in this Plan with respect
          to that Participant.

15.  EFFECT ON OPTIONS OF TERMINATION OF SERVICE FOR DISABILITY.

     Except as otherwise provided in a Participant's Option Agreement, a
Participant who ceases to be an employee, director or consultant of the Company
or of an Affiliate by reason of Disability may exercise any Option granted to
such Participant:

     a.   To the extent that the Option has become exercisable but has not been
          exercised on the date of Disability; and

     b.   In the event rights to exercise the Option accrue periodically, to the
          extent of a pro rata portion through the date of Disability of any
          additional vesting rights that would have accrued on the next vesting
          date had the Participant not become Disabled. The proration shall be
          based upon the number of days accrued in the current vesting period
          prior to the date of Disability.

     A Disabled Participant may exercise such rights only within the period
ending one (1) year after the date of the Participant's termination of
employment, directorship or consultancy, as the case may be, notwithstanding
that the Participant might have been able to exercise the Option as to some or
all of the Shares on a later date if the Participant had not become Disabled and
had continued to be an employee, director or consultant or, if earlier, within
the originally prescribed term of the Option.

     The Administrator shall make the determination both of whether Disability
has occurred and the date of its occurrence (unless a procedure for such
determination is set forth in another agreement between the Company and such
Participant, in which case such procedure shall be used for such determination).
If requested, the Participant shall be examined by a physician selected or
approved by the Administrator, the cost of which examination shall be paid for
by the Company.

                                       13
<Page>

16.  EFFECT ON OPTIONS OF DEATH WHILE AN EMPLOYEE, DIRECTOR OR CONSULTANT.

     Except as otherwise provided in a Participant's Option Agreement, in the
event of the death of a Participant while the Participant is an employee,
director or consultant of the Company or of an Affiliate, such Option may be
exercised by the Participant's Survivors:

     a.   To the extent that the Option has become exercisable but has not been
          exercised on the date of death; and

     b.   In the event rights to exercise the Option accrue periodically, to the
          extent of a pro rata portion through the date of death of any
          additional vesting rights that would have accrued on the next vesting
          date had the Participant not died. The proration shall be based upon
          the number of days accrued in the current vesting period prior to the
          Participant's date of death.

     If the Participant's Survivors wish to exercise the Option, they must take
all necessary steps to exercise the Option within one (1) year after the date of
death of such Participant, notwithstanding that the decedent might have been
able to exercise the Option as to some or all of the Shares on a later date if
he or she had not died and had continued to be an employee, director or
consultant or, if earlier, within the originally prescribed term of the Option.

17.  EFFECT OF TERMINATION OF SERVICE ON UNACCEPTED STOCK GRANTS.

     In the event of a termination of service (whether as an employee, director
or consultant) with the Company or an Affiliate for any reason before the
Participant has accepted a Stock Grant, such offer shall terminate.

     For purposes of this Paragraph 17 and Paragraph 18 below, a Participant to
whom a Stock Grant has been offered and accepted under the Plan who is absent
from work with the Company or with an Affiliate because of temporary disability
(any disability other than a permanent and total Disability as defined in
Paragraph 1 hereof), or who is on leave of absence for any purpose, shall not,
during the period of any such absence, be deemed, by virtue of such absence
alone, to have terminated such Participant's employment, director status or
consultancy with the Company or with an Affiliate, except as the Administrator
may otherwise expressly provide.

     In addition, for purposes of this Paragraph 17 and Paragraph 18 below, any
change of employment or other service within or among the Company and any
Affiliates shall not be treated as a termination of employment, director status
or consultancy so long as the Participant continues to be an employee, director
or consultant of the Company or any Affiliate.

                                       14
<Page>

18.  EFFECT ON STOCK GRANTS OF TERMINATION OF SERVICE OTHER THAN "FOR CAUSE" OR
     DEATH OR DISABILITY.

     Except as otherwise provided in a Participant's Agreement, in the event of
a termination of service (whether as an employee, director or consultant), other
than termination "for cause," Disability, or death for which events there are
special rules in Paragraphs 19, 20, and 21, respectively, before all Company
rights of repurchase shall have lapsed, then the Company shall have the right to
repurchase that number of Shares subject to a Stock Grant as to which the
Company's repurchase rights have not lapsed.

19.  EFFECT ON STOCK GRANTS OF TERMINATION OF SERVICE "FOR CAUSE".

     Except as otherwise provided in a Participant's Agreement, the following
rules apply if the Participant's service (whether as an employee, director or
consultant) with the Company or an Affiliate is terminated "for cause":

     a.   All Shares subject to any Stock Grant shall be immediately subject to
          repurchase by the Company at the purchase price, if any, thereof.

     b.   For purposes of this Plan, "cause" shall include (and is not limited
          to) dishonesty with respect to the employer, insubordination,
          substantial malfeasance or non-feasance of duty, unauthorized
          disclosure of confidential information, breach by the Participant of
          any provision of any employment, consulting, advisory, nondisclosure,
          inventions assignment, non-competition or similar agreement between
          the Participant and the Company, and conduct substantially prejudicial
          to the business of the Company or any Affiliate. The determination of
          the Administrator as to the existence of "cause" will be conclusive on
          the Participant and the Company.

     c.   "Cause" is not limited to events which have occurred prior to a
          Participant's termination of service, nor is it necessary that the
          Administrator's finding of "cause" occur prior to termination. If the
          Administrator determines, subsequent to a Participant's termination of
          service, that either prior or subsequent to the Participant's
          termination the Participant engaged in conduct which would constitute
          "cause," then the Company's right to repurchase all of such
          Participant's Shares shall apply.

     d.   Any provision in an agreement between the Participant and the Company
          or an Affiliate, which contains a conflicting definition of "cause"
          for termination and which is in effect at the time of such
          termination, shall supersede the definition in this Plan with respect
          to that Participant.

                                       15
<Page>

20.  EFFECT ON STOCK GRANTS OF TERMINATION OF SERVICE FOR DISABILITY.

     Except as otherwise provided in a Participant's Agreement, the following
rules apply if a Participant ceases to be an employee, director or consultant of
the Company or of an Affiliate by reason of Disability: to the extent the
Company's rights of repurchase have not lapsed on the date of Disability, they
shall be exercisable; provided, however, that in the event such rights of
repurchase lapse periodically, such rights shall lapse to the extent of a pro
rata portion of the Shares subject to such Stock Grant through the date of
Disability as would have lapsed had the Participant not become Disabled. The
proration shall be based upon the number of days accrued prior to the date of
Disability.

     The Administrator shall make the determination both of whether Disability
has occurred and the date of its occurrence (unless a procedure for such
determination is set forth in another agreement between the Company and such
Participant, in which case such procedure shall be used for such determination).
If requested, the Participant shall be examined by a physician selected or
approved by the Administrator, the cost of which examination shall be paid for
by the Company.

21.  EFFECT ON STOCK GRANTS OF DEATH WHILE AN EMPLOYEE, DIRECTOR OR CONSULTANT.

     Except as otherwise provided in a Participant's Agreement, the following
rules apply in the event of the death of a Participant while the Participant is
an employee, director or consultant of the Company or of an Affiliate: to the
extent the Company's rights of repurchase have not lapsed on the date of death,
they shall be exercisable; provided, however, that in the event such rights of
repurchase lapse periodically, such rights shall lapse to the extent of a pro
rata portion of the Shares subject to such Stock Grant through the date of death
as would have lapsed had the Participant not died. The proration shall be based
upon the number of days accrued prior to the Participant's death.

22.  PURCHASE FOR INVESTMENT.

     Unless the offering and sale of the Shares to be issued upon the particular
exercise or acceptance of a Stock Right shall have been effectively registered
under the Securities Act of 1933, as now in force or hereafter amended (the
"1933 Act"), the Company shall be under no obligation to issue the Shares
covered by such exercise unless and until the following conditions have been
fulfilled:

     a.   The person(s) who exercise(s) or accept(s) such Stock Right shall
          warrant to the Company, prior to the receipt of such Shares, that such
          person(s) are acquiring such Shares for their own respective accounts,
          for investment, and not with a view to, or for sale in connection
          with, the distribution of any such Shares, in which event the
          person(s) acquiring such Shares shall be bound by the provisions of
          the

                                       16
<Page>

          following legend which shall be endorsed upon the certificate(s)
          evidencing their Shares issued pursuant to such exercise or such
          grant:

                 "The shares represented by this certificate have been taken for
                 investment and they may not be sold or otherwise transferred by
                 any person, including a pledgee, unless (1) either (a) a
                 Registration Statement with respect to such shares shall be
                 effective under the Securities Act of 1933, as amended, or (b)
                 the Company shall have received an opinion of counsel
                 satisfactory to it that an exemption from registration under
                 such Act is then available, and (2) there shall have been
                 compliance with all applicable state securities laws."

     b.   At the discretion of the Administrator, the Company shall have
          received an opinion of its counsel that the Shares may be issued upon
          such particular exercise or acceptance in compliance with the 1933 Act
          without registration thereunder.

23.  DISSOLUTION OR LIQUIDATION OF THE COMPANY.

     Upon the dissolution or liquidation of the Company, all Options granted
under this Plan which as of such date shall not have been exercised and all
Stock Grants and Stock-Based Awards which have not been accepted, will terminate
and become null and void; provided, however, that if the rights of a Participant
or a Participant's Survivors have not otherwise terminated and expired, the
Participant or the Participant's Survivors will have the right immediately prior
to such dissolution or liquidation to exercise or accept any Stock Right to the
extent that the Stock Right is exercisable or subject to acceptance as of the
date immediately prior to such dissolution or liquidation. Upon the dissolution
or liquidation of the Company, any outstanding Stock-Based Awards shall
immediately terminate unless otherwise determined by the Administrator or
specifically provided in the applicable Agreement.

24.  ADJUSTMENTS.

     Upon the occurrence of any of the following events, a Participant's rights
with respect to any Stock Right granted to him or her hereunder shall be
adjusted as hereinafter provided, unless otherwise specifically provided in a
Participant's Agreement:

     A.   STOCK DIVIDENDS AND STOCK SPLITS. If (i) the shares of Common Stock
shall be subdivided or combined into a greater or smaller number of shares or if
the Company shall issue any shares of Common Stock as a stock dividend on its
outstanding Common Stock, or (ii) additional shares or new or different shares
or other securities of the Company or other non-cash assets are distributed with
respect to such shares of Common Stock, the number of shares of Common Stock
deliverable upon the exercise of an Option or acceptance of a Stock Grant may be
appropriately increased or decreased proportionately, and appropriate
adjustments may be made including, in the purchase price per share to reflect
such events. The number of Shares

                                       17
<Page>

subject to the limitation in Paragraphs 3(a), 3(c) and 4(c) shall also be
proportionately adjusted upon the occurrence of such events.

     B.   CORPORATE TRANSACTIONS. If the Company is to be consolidated with or
acquired by another entity in a merger, sale of all or substantially all of the
Company's assets other than a transaction to merely change the state of
incorporation (a "Corporate Transaction"), the Administrator or the board of
directors of any entity assuming the obligations of the Company hereunder (the
"Successor Board"), shall, as to outstanding Options, either (i) make
appropriate provision for the continuation of such Options by substituting on an
equitable basis for the Shares then subject to such Options either the
consideration payable with respect to the outstanding shares of Common Stock in
connection with the Corporate Transaction or securities of any successor or
acquiring entity; or (ii) upon written notice to the Participants, provide that
all Options must be exercised, within a specified number of days of the date of
such notice at the end of which period the Options shall terminate (all Options
shall for purposes of this clause (ii) be made fully vested and exercisable
immediately prior to their termination); or (iii) terminate all Options in
exchange for a cash payment equal to the excess of the Fair Market Value of the
Shares subject to such Options over the exercise price thereof (all Options
shall for purposes of this clause (iii) be made fully vested and immediately
exercisable immediately prior to their termination).

     With respect to outstanding Stock Grants, the Administrator or the
Successor Board, shall either (i) make appropriate provisions for the
continuation of such Stock Grants on the same terms and conditions by
substituting on an equitable basis for the Shares then subject to such Stock
Grants either the consideration payable with respect to the outstanding Shares
of Common Stock in connection with the Corporate Transaction or securities of
any successor or acquiring entity; or (ii) terminate all Stock Grants in
exchange for a cash payment equal to the excess of the Fair Market Value of the
Shares (without regard to repurchase rights of the Company) subject to such
Stock Grants over the purchase price thereof, if any.

     C.   RECAPITALIZATION OR REORGANIZATION. In the event of a recapitalization
or reorganization of the Company, other than a Corporate Transaction, pursuant
to which securities of the Company or of another corporation are issued with
respect to the outstanding shares of Common Stock, a Participant upon exercising
an Option or accepting a Stock Grant after the recapitalization or
reorganization shall be entitled to receive for the purchase price paid upon
such exercise or acceptance the number of replacement securities which would
have been received if such Option had been exercised or Stock Grant accepted
prior to such recapitalization or reorganization.

     D.   ADJUSTMENTS TO STOCK-BASED AWARDS. Upon the happening of any of the
events described in Subparagraphs A, B or C above, any outstanding Stock-Based
Award shall be appropriately adjusted to reflect the events described in such
Subparagraphs. The Administrator or the Successor Board shall determine the
specific adjustments to be made under this Paragraph 24 and, subject to
Paragraph 4, its determination shall be conclusive.

     E.   MODIFICATION OF ISOs. Notwithstanding the foregoing, any adjustments
made pursuant to Subparagraph A, B or C above with respect to ISOs shall be made
only after the

                                       18
<Page>

Administrator determines whether such adjustments would constitute a
"modification" of such ISOs (as that term is defined in Section 424(h) of the
Code) or would cause any adverse tax consequences for the holders of such ISOs.
If the Administrator determines that such adjustments made with respect to ISOs
would constitute a modification of such ISOs, it may refrain from making such
adjustments, unless the holder of an ISO specifically requests in writing that
such adjustment be made and such writing indicates that the holder has full
knowledge of the consequences of such "modification" on his or her income tax
treatment with respect to the ISO.

     F.   CHANGE OF CONTROL. In the event of either

                 (A) a Corporate Transaction that also constitutes a Change of
Control, where outstanding options are assumed or substituted in accordance with
the first paragraph of Subparagraph B clause (i) above and, with respect to
Stock Grants, in accordance with the second paragraph of Subparagraph B clause
(i); or

                 (B) a Change of Control that does not also constitute a
Corporate Transaction,

if within six months after the date of such Change of Control, (i) a
Participant's service is terminated by the Company or an Affiliate for any
reason other than Cause; or (ii) a Participant terminates his or her service as
a result of being required to change the principal location where he or she
renders services to a location more than 50 miles from his or her location of
employment or consultancy immediately prior to the Change of Control; or (iii)
the Participant terminates his or her service after there occurs a material
adverse change in a Participant's duties, authority or responsibilities which
causes such Participant's position with the Company to become of significantly
less responsibility or authority than such Participant's position was
immediately prior to the Change of Control, THEN all of such Participant's
Options outstanding under the Plan shall become fully vested and immediately
exercisable as of the date of termination of such Participant, unless in any
such case an Option has otherwise expired or been terminated pursuant to its
terms or the terms of the Plan and any repurchase rights of the Company with
respect to outstanding Stock Grants that have not lapsed or expired prior to
such Change of Control shall terminate as of the date of termination of such
Participant.

25.  ISSUANCES OF SECURITIES.

     Except as expressly provided herein, no issuance by the Company of shares
of stock of any class, or securities convertible into shares of stock of any
class, shall affect, and no adjustment by reason thereof shall be made with
respect to, the number or price of shares subject to Stock Rights. Except as
expressly provided herein, no adjustments shall be made for dividends paid in
cash or in property (including without limitation, securities) of the Company
prior to any issuance of Shares pursuant to a Stock Right.

                                       19
<Page>

26.  FRACTIONAL SHARES.

     No fractional shares shall be issued under the Plan and the person
exercising a Stock Right shall receive from the Company cash in lieu of such
fractional shares equal to the Fair Market Value thereof.

27.  CONVERSION OF ISOs INTO NON-QUALIFIED OPTIONS; TERMINATION OF ISOs.

     The Administrator, at the written request of any Participant, may in its
discretion take such actions as may be necessary to convert such Participant's
ISOs (or any portions thereof) that have not been exercised on the date of
conversion into Non-Qualified Options at any time prior to the expiration of
such ISOs, regardless of whether the Participant is an employee of the Company
or an Affiliate at the time of such conversion. At the time of such conversion,
the Administrator (with the consent of the Participant) may impose such
conditions on the exercise of the resulting Non-Qualified Options as the
Administrator in its discretion may determine, provided that such conditions
shall not be inconsistent with this Plan. Nothing in the Plan shall be deemed to
give any Participant the right to have such Participant's ISOs converted into
Non-Qualified Options, and no such conversion shall occur until and unless the
Administrator takes appropriate action. The Administrator, with the consent of
the Participant, may also terminate any portion of any ISO that has not been
exercised at the time of such conversion.

28.  WITHHOLDING.

     In the event that any federal, state, or local income taxes, employment
taxes, Federal Insurance Contributions Act ("F.I.C.A.") withholdings or other
amounts are required by applicable law or governmental regulation to be withheld
from the Participant's salary, wages or other remuneration in connection with
the exercise or acceptance of a Stock Right or in connection with a
Disqualifying Disposition (as defined in Paragraph 29) or upon the lapsing of
any right of repurchase, the Company may withhold from the Participant's
compensation, if any, or may require that the Participant advance in cash to the
Company, or to any Affiliate of the Company which employs or employed the
Participant, the statutory minimum amount of such withholdings unless a
different withholding arrangement, including the use of shares of the Company's
Common Stock or a promissory note, is authorized by the Administrator (and
permitted by law). For purposes hereof, the fair market value of the shares
withheld for purposes of payroll withholding shall be determined in the manner
provided in Paragraph 1 above, as of the most recent practicable date prior to
the date of exercise. If the fair market value of the shares withheld is less
than the amount of payroll withholdings required, the Participant may be
required to advance the difference in cash to the Company or the Affiliate
employer. The Administrator in its discretion may condition the exercise of an
Option for less than the then Fair Market Value on the Participant's payment of
such additional withholding.

                                       20
<Page>

29.  NOTICE TO COMPANY OF DISQUALIFYING DISPOSITION.

     Each Employee who receives an ISO must agree to notify the Company in
writing immediately after the Employee makes a "Disqualifying Disposition" of
any shares acquired pursuant to the exercise of an ISO. A Disqualifying
Disposition is defined in Section 424(c) of the Code and includes any
disposition (including any sale or gift) of such shares before the later of (a)
two years after the date the Employee was granted the ISO, or (b) one year after
the date the Employee acquired Shares by exercising the ISO, except as otherwise
provided in Section 424(c) of the Code. If the Employee has died before such
stock is sold, these holding period requirements do not apply and no
Disqualifying Disposition can occur thereafter.

30.  TERMINATION OF THE PLAN.

     The Plan will terminate on April 13, 2015 the date which is ten (10) years
from the EARLIER of the date of its adoption by the Board of Directors and the
date of its approval by the shareholders of the Company. The Plan may be
terminated at an earlier date by vote of the shareholders or the Board of
Directors of the Company; provided, however, that any such earlier termination
shall not affect any Agreements executed prior to the effective date of such
termination.

31.  AMENDMENT OF THE PLAN AND AGREEMENTS.

     The Plan may be amended by the shareholders of the Company. The Plan may
also be amended by the Administrator, including, without limitation, to the
extent necessary to qualify any or all outstanding Stock Rights granted under
the Plan or Stock Rights to be granted under the Plan for favorable federal
income tax treatment (including deferral of taxation upon exercise) as may be
afforded incentive stock options under Section 422 of the Code, and to the
extent necessary to qualify the shares issuable upon exercise or acceptance of
any outstanding Stock Rights granted, or Stock Rights to be granted, under the
Plan for listing on any national securities exchange or quotation in any
national automated quotation system of securities dealers. Any amendment
approved by the Administrator which the Administrator determines is of a scope
that requires shareholder approval shall be subject to obtaining such
shareholder approval. Any modification or amendment of the Plan shall not,
without the consent of a Participant, adversely affect his or her rights under a
Stock Right previously granted to him or her. With the consent of the
Participant affected, the Administrator may amend outstanding Agreements in a
manner which may be adverse to the Participant but which is not inconsistent
with the Plan. In the discretion of the Administrator, outstanding Agreements
may be amended by the Administrator in a manner which is not adverse to the
Participant.

32.  EMPLOYMENT OR OTHER RELATIONSHIP.

     Nothing in this Plan or any Agreement shall be deemed to prevent the
Company or an Affiliate from terminating the employment, consultancy or director
status of a Participant, nor to

                                       21
<Page>

prevent a Participant from terminating his or her own employment, consultancy or
director status or to give any Participant a right to be retained in employment
or other service by the Company or any Affiliate for any period of time.

33.  GOVERNING LAW.

     This Plan shall be construed and enforced in accordance with the law of the
State of Delaware.

                                       22<Page>

                                                                 Exhibit 10.2(a)

INCENTIVE STOCK OPTION AGREEMENT                   _____ SHARES OF COMMON STOCK,
NO.                                                $.0001 PAR VALUE PER SHARE

                           SYNTA PHARMACEUTICALS CORP.

                             _________________, 2005

     As of _________ (the "Grant Date"), Synta Pharmaceuticals Corp. (the
"Company"), a Delaware corporation, grants to _______________ (the "Employee")
the right and option (the "Option") to purchase up to _________ shares of the
Common Stock, $.0001 par value per share, of the Company (the "Shares") at a
purchase price of $________ per share (the "Purchase Price") and on the terms
and subject to the conditions set forth in the Company's 2005 Stock Plan (the
"Plan"), United States securities and tax laws and this Agreement.

     THIS AGREEMENT DOES NOT SET FORTH ALL OF THE TERMS AND CONDITIONS OF THE
PLAN, WHICH IS HEREBY INCORPORATED INTO AND MADE A PART OF THIS AGREEMENT BY
REFERENCE. ANY TERMS USED AND NOT DEFINED HEREIN HAVE THE SAME MEANINGS AS IN
THE PLAN. THE PARTICIPANT ACKNOWLEDGES THAT HE OR SHE HAS RECEIVED A COPY OF THE
PLAN FROM THE COMPANY AND HAS CAREFULLY READ THE TERMS AND CONDITIONS OF THE
PLAN AND THIS AGREEMENT.

SYNTA PHARMACEUTICALS CORP.

By:  ____________________________________
Its: ____________________________________

<Page>

     1.     GRANT OF OPTION.

     The Company hereby grants to the Employee the right and option to purchase
all or any part of an aggregate of _______________ Shares, on the terms and
conditions and subject to all the limitations set forth herein, under United
States securities and tax laws, and in the Plan, which is incorporated herein by
reference. The Employee acknowledges receipt of a copy of the Plan. The Option
is intended to qualify for special federal tax treatment as an "incentive stock
option" pursuant to Section 422 of the Internal Revenue Code of 1986, as amended
(the "Code").

     2.     PURCHASE PRICE.

     The purchase price of the Shares covered by the Option shall be $_____ per
Share, subject to adjustment, as provided in the Plan, in the event of a stock
split, reverse stock split or other events affecting the holders of Shares (the
"Purchase Price"). Payment shall be made in accordance with Section 9 of the
Plan.

     3.     EXERCISABILITY OF OPTION.

     Subject to the terms and conditions set forth in this Agreement and the
Plan, the Option granted hereby shall become exercisable in cumulative
installments of (i) 25% of the Shares on ________________________, and (ii)
6.25% of the Shares on the last day of each calendar quarter thereafter.
Notwithstanding the foregoing, the Option shall become vested and exercisable in
accordance with the terms and conditions set forth in Sections 24B and F of the
Plan.

     4.     TERM OF OPTION.

     The Option shall terminate ten years from the date of this Agreement or, if
the Employee owns as of the date hereof more than 10% of the total combined
voting power of all classes of capital stock of the Company or an Affiliate,
five years from the date of this Agreement, but shall be subject to earlier
termination as provided herein or in the Plan.

     If the Employee ceases to be an employee of the Company or of an Affiliate
(for any reason other than the death or Disability of the Employee or
termination of the Employee's employment for "cause" [(AS DEFINED IN THE PLAN)
CONSIDER OTHER DEFINITIONS]), the Option may be exercised, if it has not
previously terminated, within three months after the date the Employee ceases to
be an employee of the Company or an Affiliate, or within the originally
prescribed term of the Option, whichever is earlier, but may not be exercised
thereafter. In such event, the Option shall be exercisable only to the extent
that the Option has become exercisable and is in effect at the date of such
cessation of employment.

     Notwithstanding the foregoing, in the event of the Employee's Disability or
death within three months after the termination of employment, the Employee or
the Employee's Survivors may exercise the Option within one year after the date
of the Employee's termination of employment, but in no event after the date of
expiration of the term of the Option.

     In the event the Employee's employment is terminated by the Employee's
employer for "cause" [(AS DEFINED IN THE PLAN)], the Employee's right to
exercise any unexercised portion of this Option shall cease immediately as of
the time the Employee is notified his or her employment is terminated for
"cause," and this Option shall thereupon terminate. Notwithstanding anything
herein to the contrary, if subsequent to the Employee's termination as an
employee, but prior to the exercise of the Option, the Board of Directors of the
Company determines that, either prior or subsequent to the Employee's

                                        1
<Page>

termination, the Employee engaged in conduct which would constitute "cause,"
then the Employee shall immediately cease to have any right to exercise the
Option and this Option shall thereupon terminate.

     In the event of the Disability of the Employee, as determined in accordance
with the Plan, the Option shall be exercisable within one year after the
Employee's termination of employment or, if earlier, within the term originally
prescribed by the Option. In such event, the Option shall be exercisable:

     (a)    to the extent that the Option has become exercisable but has not
            been exercised as of the date of Disability; and

     (b)    in the event rights to exercise the Option accrue periodically, to
            the extent of a pro rata portion through the date of Disability of
            any additional vesting rights that would have accrued on the next
            vesting date had the Employee not become Disabled. The proration
            shall be based upon the number of days accrued in the current
            vesting period prior to the date of Disability.

     In the event of the death of the Employee while an employee of the Company
or of an Affiliate, the Option shall be exercisable by the Participant's
Survivors within one year after the date of death of the Employee or, if
earlier, within the originally prescribed term of the Option. In such event, the
Option shall be exercisable:

     (x)    to the extent that the Option has become exercisable but has not
            been exercised as of the date of death; and

     (y)    in the event rights to exercise the Option accrue periodically, to
            the extent of a pro rata portion through the date of death of any
            additional vesting rights that would have accrued on the next
            vesting date had the Employee not died. The proration shall be based
            upon the number of days accrued in the current vesting period prior
            to the Employee's date of death.

     5.     METHOD OF EXERCISING OPTION.

     Subject to the terms and conditions of this Agreement, the Option may be
exercised by written notice to the Company or its designee, in substantially the
form of EXHIBIT A attached hereto. Such notice shall state the number of Shares
with respect to which the Option is being exercised and shall be signed by the
person exercising the Option. Payment of the purchase price for such Shares
shall be made in accordance with Section 9 of the Plan. The Company shall
deliver such Shares as soon as practicable after the notice shall be received,
provided, however, that the Company may delay issuance of such Shares until
completion of any action or obtaining of any consent, which the Company deems
necessary under any applicable law (including, without limitation, state
securities or "blue sky" laws). The Shares as to which the Option shall have
been so exercised shall be registered in the Company's share register in the
name of the person so exercising the Option (or, if the Option shall be
exercised by the Employee and if the Employee shall so request in the notice
exercising the Option, shall be registered in the Company's share register in
the name of the Employee and another person jointly, with right of survivorship)
and shall be delivered as provided above to or upon the written order of the
person exercising the Option. In the event the Option shall be exercised,
pursuant to Section 4 hereof, by any person other than the Employee, such notice
shall be accompanied by appropriate proof of the right of such person to
exercise the Option. All Shares that shall be purchased upon the exercise of the
Option as provided herein shall be fully paid and nonassessable.

                                        2
<Page>

     6.     PARTIAL EXERCISE.

     Exercise of this Option to the extent above stated may be made in part at
any time and from time to time within the above limits, except that no
fractional share shall be issued pursuant to this Option.

     7.     NON-ASSIGNABILITY.

     The Option shall not be transferable by the Employee otherwise than by will
or by the laws of descent and distribution. The Option shall be exercisable,
during the Employee's lifetime, only by the Employee (or, in the event of legal
incapacity or incompetency, by the Employee's guardian or representative) and
shall not be assigned, pledged or hypothecated in any way (whether by operation
of law or otherwise) and shall not be subject to execution, attachment or
similar process. Any attempted transfer, assignment, pledge, hypothecation or
other disposition of the Option or of any rights granted hereunder contrary to
the provisions of this Section 7, or the levy of any attachment or similar
process upon the Option shall be null and void.

     8.     NO RIGHTS AS STOCKHOLDER UNTIL EXERCISE.

     The Employee shall have no rights as a stockholder with respect to Shares
subject to this Agreement until registration of the Shares in the Company's
share register in the name of the Employee. Except as is expressly provided in
the Plan with respect to certain changes in the capitalization of the Company,
no adjustment shall be made for dividends or similar rights for which the record
date is prior to the date of such registration.

     9.     ADJUSTMENTS.

     The Plan contains provisions covering the treatment of Options in a number
of contingencies such as stock splits and mergers. Provisions in the Plan for
adjustment with respect to stock subject to Options and the related provisions
with respect to successors to the business of the Company are hereby made
applicable hereunder and are incorporated herein by reference.

     10.    TAXES.

     The Employee acknowledges that any income or other taxes due from him or
her with respect to this Option or the Shares issuable pursuant to this Option
shall be the Employee's responsibility.

     In the event of a Disqualifying Disposition (as defined in Section 15
below) or if the Option is converted into a Non-Qualified Option and such
Non-Qualified Option is exercised, the Company may withhold from the Employee's
remuneration, if any, the minimum statutory amount of federal, state and local
withholding taxes attributable to such amount that is considered compensation
includable in such person's gross income. At the Company's discretion, the
amount required to be withheld may be withheld in cash from such remuneration,
or in kind from the Shares otherwise deliverable to the Employee on exercise of
the Option. The Employee further agrees that, if the Company does not withhold
an amount from the Employee's remuneration sufficient to satisfy the Company's
income tax withholding obligation, the Employee will reimburse the Company on
demand, in cash, for the amount under-withheld.

     11.    PURCHASE FOR INVESTMENT.

     Unless the offering and sale of the Shares to be issued upon the particular
exercise of the Option shall have been effectively registered under the
Securities Act of 1933, as now in force or hereafter

                                        3
<Page>

amended (the "1933 Act"), the Company shall be under no obligation to issue the
Shares covered by such exercise unless and until the following conditions have
been fulfilled:

     (a)    The person(s) who exercise the Option shall warrant to the Company,
            at the time of such exercise, that such person(s) are acquiring such
            Shares for their own respective accounts, for investment, and not
            with a view to, or for sale in connection with, the distribution of
            any such Shares, in which event the person(s) acquiring such Shares
            shall be bound by the provisions of the following legend which shall
            be endorsed upon the certificate(s) evidencing the Shares issued
            pursuant to such exercise:

                 "The shares represented by this certificate have been taken for
                 investment and they may not be sold or otherwise transferred by
                 any person, including a pledgee, unless (1) either (a) a
                 Registration Statement with respect to such shares shall be
                 effective under the Securities Act of 1933, as amended, or (b)
                 the Company shall have received an opinion of counsel
                 satisfactory to it that an exemption from registration under
                 such Act is then available, and (2) there shall have been
                 compliance with all applicable state securities laws;" and

     (b)    If the Company so requires, the Company shall have received an
            opinion of its counsel that the Shares may be issued upon such
            particular exercise in compliance with the 1933 Act without
            registration thereunder. Without limiting the generality of the
            foregoing, the Company may delay issuance of the Shares until
            completion of any action or obtaining of any consent, which the
            Company deems necessary under any applicable law (including without
            limitation state securities or "blue sky" laws).

     12.    RESTRICTIONS ON TRANSFER OF SHARES.

     12.1   If, in connection with a registration statement filed by the Company
            pursuant to the Securities Act, the Company or its underwriter so
            requests, the Employee will agree not to sell any Shares for a
            period not to exceed 180 days following the effectiveness of such
            registration.

     12.2   The Employee acknowledges and agrees that neither the Company, its
            shareholders nor its directors and officers, has any duty or
            obligation to disclose to the Employee any material information
            regarding the business of the Company or affecting the value of the
            Shares before, at the time of, or following a termination of the
            employment of the Employee by the Company, including, without
            limitation, any information concerning plans for the Company to make
            a public offering of its securities or to be acquired by or merged
            with or into another firm or entity.

     13.    NO OBLIGATION TO EMPLOY.

     The Company is not by the Plan or this Option obligated to continue the
Employee as an employee of the Company or an Affiliate. The Employee
acknowledges: (i) that the Plan is discretionary in nature and may be suspended
or terminated by the Company at any time; (ii) that the grant of the Option is a
one-time benefit which does not create any contractual or other right to receive
future grants of options, or benefits in lieu of options; (iii) that all
determinations with respect to any such future grants, including, but not
limited to, the times when options shall be granted, the number of shares
subject to each option, the option price, and the time or times when each option
shall be exercisable, will be at the sole discretion of the Company; (iv) that
the Employee's participation in the Plan is voluntary; (v) that the value of the
Option is an extraordinary item of compensation which is outside the scope of
the Employee's employment contract, if any; and (vi) that the Option is not part
of normal or expected

                                        4
<Page>

compensation for purposes of calculating any severance, resignation, redundancy,
end of service payments, bonuses, long-service awards, pension or retirement
benefits or similar payments.

     14.    OPTION IS INTENDED TO BE AN ISO.

     The parties each intend that the Option be an ISO so that the Employee (or
the Employee's Survivors) may qualify for the favorable tax treatment provided
to holders of Options that meet the standards of Section 422 of the Code. Any
provision of this Agreement or the Plan which conflicts with the Code so that
this Option would not be deemed an ISO is null and void and any ambiguities
shall be resolved so that the Option qualifies as an ISO. Nonetheless, if the
Option is determined not to be an ISO, the Employee understands that neither the
Company nor any Affiliate is responsible to compensate him or her or otherwise
make up for the treatment of the Option as a Non-qualified Option and not as an
ISO. The Employee should consult with the Employee's own tax advisors regarding
the tax effects of the Option and the requirements necessary to obtain favorable
tax treatment under Section 422 of the Code, including, but not limited to,
holding period requirements.

     15.    NOTICE TO COMPANY OF DISQUALIFYING DISPOSITION.

     The Employee agrees to notify the Company in writing immediately after the
Employee makes a Disqualifying Disposition of any of the Shares acquired
pursuant to the exercise of the Option. A Disqualifying Disposition is defined
in Section 424(c) of the Code and includes any disposition (including any sale)
of such Shares before the later of (a) two years after the date the Employee was
granted the Option or (b) one year after the date the Employee acquired Shares
by exercising the Option, except as otherwise provided in Section 424(c) of the
Code. If the Employee has died before the Shares are sold, these holding period
requirements do not apply and no Disqualifying Disposition can occur thereafter.

     16.    NOTICES.

     Any notices required or permitted by the terms of this Agreement or the
Plan shall be given by recognized courier service, facsimile, registered or
certified mail, return receipt requested, addressed as follows:

If to the Company:

            Synta Pharmaceuticals Corp.
            45 Hartwell Avenue
            Lexington, MA 02421
            Attention: Vice President Legal Affairs

If to the Employee:

            _____________________________
            _____________________________
            _____________________________

or to such other address or addresses of which notice in the same manner has
previously been given. Any such notice shall be deemed to have been given upon
the earlier of receipt, one business day following delivery to a recognized
courier service or three business days following mailing by registered or
certified mail.

                                        5
<Page>

     17.    GOVERNING LAW.

     This Agreement shall be construed and enforced in accordance with the law
of the State of Delaware, without giving effect to the conflict of law
principles thereof. For the purpose of litigating any dispute that arises under
this Agreement, the parties hereby consent to exclusive jurisdiction in the
Commonwealth of Massachusetts and agree that such litigation shall be conducted
in the courts of Middlesex County, Massachusetts or the federal courts of the
United States for the District of Massachusetts.

     18.    BENEFIT OF AGREEMENT.

     Subject to the provisions of the Plan and the other provisions hereof, this
Agreement shall be for the benefit of and shall be binding upon the heirs,
executors, administrators, successors and assigns of the parties hereto.

     19.    ENTIRE AGREEMENT.

     This Agreement, together with the Plan, embodies the entire agreement and
understanding between the parties hereto with respect to the subject matter
hereof and supersedes all prior oral or written agreements and understandings
relating to the subject matter hereof. No statement, representation, warranty,
covenant or agreement not expressly set forth in this Agreement shall affect or
be used to interpret, change or restrict, the express terms and provisions of
this Agreement, provided, however, in any event, this Agreement shall be subject
to and governed by the Plan.

     20.    MODIFICATIONS AND AMENDMENTS.

     The terms and provisions of this Agreement may be modified or amended as
provided in the Plan.

     21.    WAIVERS AND CONSENTS.

     Except as provided in the Plan, the terms and provisions of this Agreement
may be waived, or consent for the departure therefrom granted, only by written
document executed by the party entitled to the benefits of such terms or
provisions. No such waiver or consent shall be deemed to be or shall constitute
a waiver or consent with respect to any other terms or provisions of this
Agreement, whether or not similar. Each such waiver or consent shall be
effective only in the specific instance and for the purpose for which it was
given, and shall not constitute a continuing waiver or consent.

     22.    DATA PRIVACY.

     By entering into this Agreement, the Employee: (i) authorizes the Company
and each Affiliate, and any agent of the Company or any Affiliate administering
the Plan or providing Plan recordkeeping services, to disclose to the Company or
any of its Affiliates such information and data as the Company or any such
Affiliate shall request in order to facilitate the grant of options and the
administration of the Plan; (ii) waives any data privacy rights he or she may
have with respect to such information; and (iii) authorizes the Company and each
Affiliate to store and transmit such information in electronic form.

                                        6
<Page>

                                                                       EXHIBIT A

                  NOTICE OF EXERCISE OF INCENTIVE STOCK OPTION

TO:  Synta Pharmaceuticals Corp.

Ladies and Gentlemen:

     I hereby exercise my Incentive Stock Option to purchase _________ shares
(the "Shares") of the common stock, $.0001 par value, of Synta Pharmaceuticals
Corp. (the "Company"), at the exercise price of $________ per share, pursuant to
and subject to the terms of that certain Incentive Stock Option Agreement
between the undersigned and the Company dated _______________, 200_.

     I understand the nature of the investment I am making and the financial
risks thereof. I am aware that it is my responsibility to have consulted with
competent tax and legal advisors about the relevant national, state and local
income tax and securities laws affecting the exercise of the Option and the
purchase and subsequent sale of the Shares.

     I am paying the option exercise price for the Shares as follows:

                    ________________________________________

     Please issue the Shares (check one):

     / / to me; or

     / / to me and ____________________________, as joint tenants with right of
     survivorship, at the following address:   ________________________
                                               ________________________
                                               ________________________

     My mailing address for shareholder communications, if different from the
address listed above, is:   ________________________
                            ________________________
                            ________________________

                                Very truly yours,

                                ------------------------------------------------
                                Employee (signature)

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

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

                                ------------------------------------------------
                                Social Security Number

                                       A-1

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