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                                                                   Exhibit 10.22

                              AGREEMENT AND RELEASE

         AGREEMENT AND RELEASE dated this 14th day of January, 2005, by and
between Dr. Lan Bo Chen ("DR. CHEN") and Synta Pharmaceutical Corp. (the
"COMPANY"). Dr. Chen and the Company may be referred to jointly as "THE
PARTIES."

         WHEREAS,  Dr. Chen is a founder of the Company,  serves as a member of
the Company's  board of directors, and is chair of the Company's scientific
advisory board;

         WHEREAS, during the course of their relationship, the parties
(including, in certain cases, various predecessor entities of the Company) have
had, or may have had, various oral understandings and arrangements which,
because they were not memorialized clearly in writing, have led to lack of
clarity about the nature and extent of the parties' obligations to each other
under these arrangements; and

         WHEREAS, Dr. Chen and the Company wish to resolve, for their mutual
benefit, all matters regarding such arrangements, including arrangements
relating to (i) the release by Dr. Chen of any and all claims that Dr. Chen and
his Affiliates (as defined below) and Associates (as defined below) may have
against the Company, its Predecessors (as defined below) and other related
parties, (ii) the assignment by Dr. Chen of the benefit of his interests in
certain entities to the Company and (iii) Dr. Chen's assignment of inventions,
non-competition, non-solicitation and confidentiality agreements with the
Company.

         NOW, THEREFORE, for good and valuable consideration, as more fully
described below, the sufficiency of which is hereby acknowledged, the parties
agree as follows:

1.       AGREEMENT AND RELEASE CONSIDERATION.

         As full, complete, and unconditional satisfaction, settlement and
accord of all Claims (as defined below) and in consideration of the agreements
and releases set forth herein, the Company agrees to pay to Dr. Chen a total sum
of Five Hundred Thousand Dollars ($500,000). Such amount will be paid in twenty
(20) equal payments of Twenty-Five Thousand Dollars ($25,000), the first being
made on the date of execution of this Agreement and Release, and the remaining
nineteen payments to be made every three months from the date hereof.

2.       DEFINITIONS.

         For purposes of this Agreement and Release, the following terms shall
have the meanings set forth below:

                           (i) "AFFILIATE" shall mean a person or entity that
                 directly, or indirectly through one or more intermediaries,
                 controls or is controlled by, or under common control with
                 another person or entity, and shall include without limitation,
                 both current and former directors and officers of an entity;

                           (ii) "ASSOCIATE" shall mean (a) any corporation or
                 organization (other than the Company or any of its
                 subsidiaries) of which an individual, as of the date hereof, is
                 a director, executive officer or partner or of which the
                 individual is, directly or indirectly, the beneficial owner of
                 10% or more of any class of equity securities, (b) any trust or
                 other estate in which an individual has a substantial
                 beneficial interest or as to which the individual serves as
                 trustee or in a similar fiduciary capacity, and (c) an
                 individual's spouse and, either by blood or adoption, the
                 individual's parents, children, siblings,

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                 mothers and fathers-in-law, sons and daughters-in-law, and
                 brothers and sisters-in-law; and

                           (iii) "PREDECESSOR" shall mean an entity, the major
                 portion of the business and assets of which was acquired by
                 another entity in a single transaction or in a series of
                 related transactions.

3.       RELEASES.

         (a) Dr. Chen on behalf of himself his Affiliates and Associates, and
his and their fiduciaries, representatives, agents, estates, trusts, attorneys,
executors, administrators, beneficiaries, successors and assigns (hereinafter,
the "RELEASORS"), absolutely and unconditionally releases and forever discharges
the Company, its Predecessors, Affiliates, Associates, and its and their
successors and assigns, as well as all of their past and present attorneys,
employees, insurers, representatives and agents, both individually and in any of
their official capacities (collectively, the "RELEASEES"), from any and all
actions or causes of action, disputes, suits, claims, complaints, contracts,
liabilities, agreements, promises, oral or written, debts, judgments and
damages, in law or equity, whether existing or contingent, known or unknown,
matured or not matured since the Beginning of the World thorough the Date of
this Agreement and Release (collectively, "CLAIMS"), including, without
limitation: Claims arising out of Dr. Chen's ownership interest in or
relationship with any Predecessor of the Company or any entity related to the
Company in any manner whatsoever; Claims arising out of Dr. Chen's role as a
founder, stockholder and/or director of the Company, as a consultant to the
Company, or as an individual who has provided equipment and/or services to the
Company; Claims arising from or as a consequence of any actions or omissions to
act of the Company's Board of Directors or individual directors of the Company;
Claims arising from or as a consequence of any actions or omissions to act of
any other Releasee; Claims of breach of fiduciary duty; Claims arising from or
concerning Dr. Chen's status as an owner or inventor of any assets, including
equipment, intellectual property, biological or chemical materials, processes or
know-how, compounds used by the Company, its Predecessors, Affiliates or
Associates in their businesses; Claims for compensation, reimbursement or
remuneration of any sort (such as, but without limitation, severance payments,
license payments, bonus payments, benefits, accrued vacation pay, sick pay,
reimbursable expenses, loans to the Company, expense vouchers, obligations or
commitments to grant stock options or to issue stock and all other rights to
acquire stock, if any such obligations, commitments and/or rights are claimed to
exist, and all other payments, commissions, compensations or reimbursements of
every kind and description and for whatever reason); Claims involving any
federal or state securities laws; Claims involving any federal or state law or
regulation relating to employment or employment discrimination (such as those
laws or regulations concerning discrimination on the basis of age, alienage,
race, color, creed, sex, sexual orientation, religion, national origin, handicap
status or veteran status or any military service or application for military
service); Claims involving any contract, arrangement or understanding, whether
oral or written, express or implied; or common law Claims. This release is
intended to be all-encompassing and to act as a full and total release of any
and all Claims that any of the Releasors has, may have in the future, or has had
against any or all of the Releasees resulting or arising from, relative to, or
based on facts, events or occurrences since the Beginning of the World through
the date of this Agreement and Release; however, notwithstanding the foregoing,
nothing herein is intended to or shall impair, negate or otherwise affect (i)
Dr. Chen's ownership in, or title or rights in or to, any equity interest,
whether capital stock or options or other rights to acquire capital stock, he,
his Affiliates or Associates has or have in the Company; or (ii) any vested
interest of Dr. Chen in any retirement plan or pension.

         (b) Dr. Chen, on his own behalf and on behalf of the other Releasors,
further agrees to release and discharge the Company and all other Releasees from
any and all Claims that might be made by any other person or organization on
behalf of the Releasors, and specifically waives any right to

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become, and promises not to become, a member of any class in a case in which any
Claim against the Company, or any claim in the name of the Company, is made
involving any matters subject to release pursuant to Section 3(a) (or, except as
required by law or rule of court, to assist or cooperate in the bringing of any
such claim against the Company or any other Releasee).

         (c) These releases may be pleaded by any Releasee as a full and
complete defense to any released Claim and may be used as the basis for an
injunction against any action, suit or proceeding that may be prosecuted,
instituted, or attempted in breach hereof. Nothing herein shall be deemed to
waive the right of the Company or Dr. Chen to bring an action to enforce the
terms of, or recover damages for breach of, any of the terms of this Agreement
and Release.

         (d) If the parties bring an action barred by, or in order to enforce,
these releases, the losing party shall be obligated to reimburse the prevailing
party for reasonable attorneys' fees and costs in such action.

         (e) Nothing herein is intended to or shall impair, negate or otherwise
affect any right to insurance or to indemnification either party may have under
applicable law, under the Company's Certificate of Incorporation, as amended, or
the Company's By-laws, as amended, or under any future contract specifically
with respect to indemnification entered into by the Company and Dr. Chen.

4.       ASSIGNMENT AND TRANSFER.

         To the extent that Dr. Chen, or any Affiliate or Associate retains any
remaining interest, directly or indirectly, in Kava Pharmaceuticals, Inc.,
Cancer Genomics, Inc., SinglePixel Biomedical, Inc., Three L Enterprises, and
CMAC, LLC that could result in or give rise to a distribution or payment to him
of anything of value, Dr. Chen hereby irrevocably assigns and transfers to the
Company the net benefits received by Dr. Chen or any such Affiliate or Associate
in connection with such interests, whenever they are received.

5.       CONFIDENTIALITY AND INVENTION ASSIGNMENT.

         (a) The parties acknowledge that the Company and the Predecessors have
engaged Dr. Chen on an "at-will" basis as a consultant and service provider, and
that the Company is currently compensating him for consulting services rendered
on a month-to-month schedule (all of the foregoing services being hereinafter
referred to as "CONSULTING SERVICES"). In consideration of the payments set
forth in Section 1 hereof and the payments received and to be received pursuant
to the Consulting Services, Dr. Chen hereby agrees to the confidentiality,
non-disclosure and invention assignment provisions set forth below.

         (b)      CERTAIN ACKNOWLEDGEMENTS AND AGREEMENTS.

                           (i) The parties have discussed, and Dr. Chen hereby
                  recognizes and acknowledges the competitive and proprietary
                  aspects of the business of the Company, its Affiliates and
                  Associates.

                           (ii) Dr. Chen acknowledges that a business will be
                  deemed "competitive" with the Company if, at the time Dr. Chen
                  enters into a relationship with such business or, at any time
                  within two years thereafter while Dr. Chen has a relationship
                  with such business it engages in, or is actively planning or
                  developing any service and/or the research, development or
                  commercialization of any product that is the functional
                  equivalent of, or that has or will likely have the effect of
                  materially displacing sales of

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                  services or products which (A) are performed, produced,
                  manufactured, distributed, sold, under research or active
                  development or in active planning by the Company at any time
                  while Dr. Chen is providing Consulting Services or (B) are
                  expressly identified in writing as the subject of Dr. Chen's
                  Consulting Services hereunder. If the Company requests that
                  Dr. Chen provide Consulting Services that he advises the
                  Company may be competitive with the activities of another
                  business with which he then has a relationship, the Company
                  may at its option (x) terminate the Consulting Services and
                  in connection therewith pay to Dr. Chen any fees and
                  reimburseable expenses due for all Consulting Services
                  rendered through the date of termination, or (y) require Dr.
                  Chen to terminate his services with the competitive business
                  or entity.

                           (iii) Dr. Chen further acknowledges that, while
                  performing Consulting Services to the Company, the Company,
                  its Affiliates and Associates have furnished and will furnish,
                  disclose or make available to him Confidential Information (as
                  defined below) related to the business of the Company and, its
                  Affiliates. Dr. Chen also acknowledges that such Confidential
                  Information has been developed and will be developed by the
                  Company, its Affiliates and Associates through the expenditure
                  by the Company, its Affiliates and Associates of substantial
                  time, effort and money and that all such Confidential
                  Information could be used by him to compete with the Company,
                  its Affiliates and Associates. Further, while Dr. Chen has
                  performed or in the future performs Consulting Services to the
                  Company, he has been or will be introduced to customers and
                  others with important relationships to the Company, its
                  Affiliates and Associates. Dr. Chen acknowledges that any and
                  all "goodwill" created through such introductions belongs
                  exclusively to the Company, its Affiliates and Associates,
                  including, without limitation, any goodwill created as a
                  result of direct or indirect contacts or relationships between
                  himself and any customers or other third parties doing
                  business with the Company, its Affiliates and Associates.

                           (iv) For purposes of this Agreement and Release,
                  "CONFIDENTIAL INFORMATION" means confidential and proprietary
                  information of the Company, its Predecessors, Affiliates and
                  Associates, whether in written, oral, electronic or other
                  form, including but not limited to, information and facts
                  concerning business plans; current or potential customers,
                  suppliers, licensors, licensees, partners, investors,
                  affiliates or others; training methods and materials;
                  financial information; sales prospects; client lists;
                  inventions; or any other scientific, technical or trade
                  secrets of the Company, its Predecessors Affiliates and
                  Associates or of any third party provided to Dr. Chen or the
                  Company, its Predecessors Affiliates and Associates under a
                  condition of confidentiality; provided that Confidential
                  Information will not include information that is in the public
                  domain other than through any fault or act by Dr. Chen, his,
                  Affiliates and Associates. The term "TRADE SECRETS," as used
                  in this Agreement and Release, will be given its broadest
                  possible interpretation under the law of the Commonwealth of
                  Massachusetts and will include, without limitation, anything
                  tangible or intangible or electronically kept or stored, which
                  constitutes, represents, evidences or records secret,
                  scientific, technical, merchandising, production or management
                  information, or any design, process, procedure, formula,
                  invention, improvement or other confidential or proprietary
                  information or documents.

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         (c) NON-COMPETITION; NON-SOLICITATION. While Dr. Chen performs
Consulting Services to the Company and for a period of one year following the
termination of his service to the Company for any reason or for no reason, he
will not, without the prior written consent of the Company:

                           (i) For himself or on behalf of any other person or
                  entity, directly or indirectly, either as principal, partner,
                  stockholder, officer, director, member, employee, consultant,
                  agent, representative or in any other capacity, own, manage,
                  operate or control, or be concerned, connected or employed by,
                  or otherwise associate in any manner with, engage in or have a
                  financial interest in, any business which is competitive with
                  the business of the Company (each, a "RESTRICTED ACTIVITY")
                  anywhere in the world, except that (A) nothing contained
                  herein will preclude Dr. Chen from purchasing or owning
                  securities of any such business if such securities are
                  publicly traded, and provided that his holdings do not exceed
                  one percent of the issued and outstanding securities of any
                  class of securities of such business and (B) nothing contained
                  herein will prohibit Dr. Chen from engaging in a Restricted
                  Activity for or with respect to any subsidiary, division or
                  affiliate or unit (each, a "UNIT") of an entity if that Unit
                  is not engaged in any business which is competitive with the
                  business of the Company, its Affiliates and Associates,
                  irrespective of whether some other Unit of such entity engages
                  in such competition (as long as Dr. Chen does not engage in a
                  Restricted Activity for such other Unit); or

                           (ii) Either individually or on behalf of or through
                  any third party, directly or indirectly, solicit, divert or
                  appropriate or attempt to solicit, divert or appropriate, for
                  the purpose of competing with the Company, any customers,
                  licensors, licensees, collaborative partners, or other patrons
                  of the Company, or any such person or entity with respect to
                  which the Company has developed or made a presentation (or
                  similar communication) with a view to developing a business
                  relationship; or

                           (iii) Either individually or on behalf of or through
                  any third party, directly or indirectly, (A) solicit, entice
                  or persuade or attempt to solicit, entice or persuade any
                  employee of or consultant to the Company to leave the service
                  of the Company for any reason, or (B) employ, cause to be
                  employed, or solicit the employment of, any employee of or
                  consultant to the Company while any such person is providing
                  services to the Company or within six months after any such
                  person has ceased providing services to the Company.

         (d) REASONABLENESS OF RESTRICTIONS. Dr. Chen further recognizes and
acknowledges that (i) the types of employment which are prohibited by this
Section 5 are narrow and reasonable in relation to the skills which represent
his principal salable asset both to the Company and to others and (ii) the time
period and the geographical scope of the provisions of this Section 5 are
reasonable, legitimate and fair to Dr. Chen in light of the Company's need to
effectively pursue its business plan and objectives and in light of the limited
restrictions on the type of activities prohibited herein compared to the types
of activities for which Dr. Chen is qualified to earn his livelihood.

         (e) SURVIVAL OF ACKNOWLEDGEMENTS AND AGREEMENTS. Dr. Chen's
acknowledgements and agreements set forth in this Section 5 will survive the
termination of this Agreement and Release and the termination of Dr. Chen's
service to the Company for any reason or for no reason.

         (f) PROTECTED INFORMATION. Dr. Chen will at all times, both during the
period while he performs Consulting Services to the Company and after the
termination of this Agreement and Release and the termination of his service to
the Company, for any reason or for no reason, maintain in confidence and will
not, without the prior written consent of the Company, use, except as required
in the course of performance of his duties for the Company or by court order,
disclose or give to others any Confidential Information. In the event Dr. Chen
is questioned by anyone not employed by the Company or by an employee of or a
consultant to the Company not authorized to receive Confidential Information, in
regard

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to any Confidential Information, or concerning any fact or circumstance relating
thereto, Dr. Chen will promptly notify the Company. Upon the termination of Dr.
Chen's service to the Company for any reason or for no reason, or if the Company
otherwise requests, he will return to the Company all tangible Confidential
Information and copies thereof (regardless how such Confidential Information or
copies are maintained). The terms of this sub-section are in addition to, and
not in lieu of, any statutory or other contractual or legal obligation that he
may have relating to the protection of the Company's Confidential Information.
The terms of this sub-section will survive indefinitely any termination of this
Agreement and Release and/or any termination of Dr. Chen's service to the
Company for any reason or for no reason.

         (g) PROPERTY OF THE COMPANY.

             (i) All ideas, discoveries, creations, manuscripts and
             properties, innovations, improvements, know-how, inventions,
             designs, developments, apparatus, techniques, methods, biological
             processes, cell lines, laboratory notebooks and formulae in any
             form known or not yet known throughout the world (collectively,
             the "INVENTIONS") which may be used or useful in the current or
             planned business of the Company, whether patentable,
             copyrightable or not, which Dr. Chen has conceived, reduced to
             practice or developed, or may conceive, reduce to practice or
             develop arising out of or in connection with his performance of
             Consulting Services, employment-related services or other
             services for the Company or its Predecessors in any capacity
             (and, if based on or related to any Confidential Information,
             within one years after termination of such service to the Company
             for any reason or for no reason), alone or in conjunction with
             another or others, whether during or out of regular business
             hours, whether or not on the Company's premises or with the use
             of its equipment, and whether at the request or upon the
             suggestion of the Company or otherwise, will be and hereby are
             the sole and exclusive property of the Company, and Dr. Chen will
             not publish any of the Inventions without the prior written
             consent of the Company. Without limiting the foregoing, Dr. Chen
             also acknowledges that all original works of authorship which are
             made by Dr. Chen (solely or jointly with others) within the scope
             of Dr. Chen's service to the Company and its Predecessors and
             which are protectable by copyright are "works made for hire"
             pursuant to the United States Copyright Act (17 U.S.C. Section
             101). Dr. Chen hereby assigns to the Company all of his right,
             title and interest in and to all of the foregoing. Dr. Chen
             further represents that, to the best of his knowledge and belief,
             none of the Inventions will violate or infringe upon any right,
             patent, copyright, trademark or right of privacy, or constitute
             libel or slander against or violate any other rights of any
             person, firm or corporation, and that Dr. Chen will not knowingly
             create any Invention which causes any such violation.

             (ii) To the extent that Dr. Chen has any ownership interest in
             any chemical compounds contained in the Company's compound
             library, used in any of the Company's past, current or planned
             research or development activities or which may be used or useful
             in the current or planned business of the Company, or otherwise
             located or stored at any of the Company's facilities, he assigns
             and irrevocably transfers to the Company all right title and
             interest therein.

             (iii) To the extent that Dr. Chen has clear title to equipment
             located at the Company it will remain his personal equipment, all
             other ownership interests Dr. Chen may assert in any laboratory
             or equipment or materials, used in any of the Company's past,
             current or planned research or development activities or which
             may be used or useful in the current or planned business of the
             Company, or otherwise located or stored at any of the Company's

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             facilities, he assigns and irrevocably transfers to the Company all
             right title and interest therein.

         (h) COOPERATION. At any time during Dr. Chen's service to the Company
or after the termination of Dr. Chen's service to the Company for any reason or
for no reason, Dr. Chen will cooperate fully with the Company and its attorneys
and agents in the preparation and filing of all papers and other documents as
may be required to perfect the Company's rights in and to any of such
Inventions, including, but not limited to, joining in any proceeding to obtain
letters patent, copyrights, trademarks or other legal rights with respect to any
such Inventions in the United States and in any and all other countries,
provided that the Company will bear the expense of such proceedings, and, if
after the termination of Dr. Chen's service to the Company, shall compensate Dr.
Chen at his then current per diem rate for his time spent providing such
cooperation and assistance, as evidenced by time records in reasonable detail
submitted to the Company. Any patent or other legal right so issued to Dr. Chen
personally will be assigned by Dr. Chen to the Company without charge by Dr.
Chen, his Affiliates and Associates.

         (i) LICENSING AND USE OF INVENTIONS. With respect to any Inventions,
whenever created, which Dr. Chen has not prepared or originated in the
performance of his services to the Company or its Predecessors, but which Dr.
Chen provides to the Company or which is incorporated in any Company product or
system, Dr. Chen hereby grants to the Company a royalty-free, fully paid-up,
non-exclusive, perpetual and irrevocable license throughout the world to use,
modify, create derivative works from, disclose, publish, translate, reproduce,
deliver, perform, dispose of, and to authorize others so to do, all such
Inventions. Dr. Chen will not include in any Inventions he delivers to the
Company or uses on its behalf, without the prior written approval of the
Company, any material which is or will be patented, copyrighted or trademarked
by him or others unless he provides the Company with the written permission of
the holder of any patent, copyright or trademark owner for the Company to use
such material in a manner consistent with then-current Company policy.

         (j) DISCLOSURE TO FUTURE EMPLOYERS. Dr. Chen will provide, and the
Company, in its discretion, may similarly provide, a copy of the covenants
contained in Section 5 of this Agreement and Release to any business or
enterprise which he may, directly or indirectly, own, manage, operate, finance,
join, control or in which he may participate in the ownership, management,
operation, financing, or control, or with which he may be connected as an
officer, director, employee, partner, principal, agent, representative,
consultant or otherwise.

         (k) COMPANY ACKNOWLEDGEMENT. The Company acknowledges that Dr. Chen is
affiliated with Caxton Health Holdings ("Caxton") and that Dr. Chen's
affiliation with Caxton is not in violation of this Agreement, provided that Dr.
Chen maintains the confidentiality of the Company's Confidential Information and
trade secrets and may not engage in a competitive Restricted Activity,
individually or in concert with others, in connection with his affiliation with
Caxton.

6.       NO ADMISSION.

         The parties agree and acknowledge that while this Agreement and Release
resolves the issues between the parties, it does not constitute an admission by
either party of any liability whatsoever. Neither this Agreement and Release nor
any of its terms shall be construed to be, or shall be admissible in any
proceeding as, evidence of liability by either party. However, this Agreement
and Release may be introduced in any proceeding to enforce its terms.

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7.       SEVERABILITY.

         The parties agree that each provision herein shall be treated as a
separate and independent clause, and the unenforceability of any one clause
shall in no way impair the enforceability of any of the other clauses. Moreover,
if one or more of the provisions or subparts contained in this Agreement and
Release shall for any reason be held to be excessively broad as to scope or
subject matter so as to be unenforceable at law or equity, such provision,
provisions or subparts shall be construed by limiting and reducing it or them so
as to be enforceable, to the fullest extent compatible with applicable law, in a
manner consistent with the parties' intentions.

8.       NOTICES AND PAYMENTS.

         All payments to Dr. Chen shall be made at the address set forth below,
or such other address as he shall inform the Company of in writing or, at the
Company's option, shall be made by electronic deposit to a bank account
designated by Dr. Chen. All notices and communications shall be given to the
parties at the following addresses, or such other addresses as the parties shall
provide to each other in writing:

         If to Dr. Chen:

                  Lan Bo Chen, Ph.D.
                  [ADDRESS]

         If to the Company:

                  Synta Pharmaceuticals Corp.
                  45 Hartwell Avenue
                  Lexington, MA  02421
                  Attention: Chief Executive Officer

9.       REPRESENTATIONS AND GOVERNING LAW.

         (a) This Agreement and Release, represents the complete understanding
between the parties, supersedes any and all agreements and understandings,
whether oral or written, and may not be modified, altered, changed or waived, in
whole or in part, except upon written consent of both parties. The parties agree
that the Company will not have an adequate remedy if Dr. Chen or any other
Releasor fails to comply with the provisions hereof, and that damages will not
be readily ascertainable for such breach, and that a decree of specific
performance or an injunction enjoining a breach of this Agreement and Release is
an appropriate remedy for such breach.

         (b) Dr. Chen represents that he has carefully read this Agreement and
Release, fully understands its terms, and is voluntarily executing same. In
entering into this Agreement and Release, Dr. Chen does not rely on any
representation, promise or inducement made by the Company, or any of its
representatives, agents or attorneys, with the exception of the consideration
described in this document.

         (c) This Agreement and Release shall in all respects be interpreted,
enforced and governed under the internal and domestic laws of the Commonwealth
of Massachusetts without giving effect to the principles of conflicts of law
thereof. Any dispute hereunder will be adjudicated only in the courts located in
Massachusetts. Dr. Chen hereby submits to the jurisdiction of such courts.

         (d) The parties agree to cooperate fully in the execution of any and
all documents, and the taking of any additional action, which may be necessary
or appropriate to give full force and effect to the terms and intent of this
Agreement and Release.

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         (e) The language of all parts of this Agreement and Release shall in
all cases be construed as a whole according to its fair meaning and not strictly
for or against either of the parties.

         (f) This Agreement and Release shall not be assigned by either party
but shall be binding on the parties hereto and their respective heirs, legal
representatives, successors and assigns, and shall inure to the benefit of the
Company's successors and assigns by merger or consolidation with another
company, by the sale of all or substantially all of the assets or capital stock
of the Company, or by any similar transaction in which all or substantially all
of the business of the Company is acquired. The parties acknowledge and warrant
that they have not assigned to any third party any rights, or claims of any
nature against either party or any of the Releasees specified in Section 3.

10.      COUNTERPARTS.

         This Agreement and Release may be executed in two counterparts, either
one of which need not contain the signatures of all parties, but both
counterparts when taken together will constitute one and the same agreement.

            [THE REMAINDER OF THIS PAGE IS INTENTIONALLY LEFT BLANK.]

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         IN WITNESS WHEREOF, the parties hereto have caused this Agreement and
Release to be executed as of the date set forth above.

Lan Bo Chen, Ph.D.                              Synta Pharmaceuticals Corp.

By:      /S/ Lan Bo Chen                        By:      /S/ Safi R. Bahcall
   -----------------------------------              ----------------------------
                                                        Safi R. Bahcall, Ph.D.

                                       10<Page>

                                                                 Exhibit 10.23

                    [SYNTA PHARMACEUTICALS CORP. LETTERHEAD]

                                                April 18, 2005

Lan Bo Chen, Ph.D.
[ADDRESS]

         Re:  CONSULTING AGREEMENT
              --------------------

Dear Lan Bo:

         This letter is to confirm our understanding with respect to (i) your
continued service to Synta Pharmaceuticals Corp. (the "Company") as a
consultant, (ii) your agreement not to compete with the Company, or any present
or future parent, subsidiary or affiliate of the Company (each, a "Company
Affiliate" and collectively with the Company, the "Company Group"), (iii) your
agreement to protect and preserve information and property which is confidential
and proprietary to the Company Group and (iv) your agreement with respect to the
ownership of inventions, ideas, copyrights and patents which may be used in the
business of the Company Group (the terms and conditions agreed to in this letter
are hereinafter referred to as the "Agreement"). In consideration of the mutual
promises and covenants contained in this Agreement, and for other good and
valuable consideration, the receipt and sufficiency of which are hereby mutually
acknowledged, we have agreed as follows:

         1. SERVICES.

         (a) You are hereby engaged by the Company as an independent contractor,
and not as an employee, to provide the following services to the Company (the
"Consulting Services"):

             (i) to serve as Chairman and/or a member of the Company's
Scientific Advisory Board;

             (ii) to carry out various projects which the Chief Executive
Officer or the Board of Directors of the Company may request and assign to you
from time to time; and

             (iii) to bring to the attention of the Company from time to time
information about inventions, scientific developments, research programs,
available chemical compounds or biological entities, ideas, formulations,
business development opportunities, potential employees, scientific contacts and
the like, that may be of interest to the Company in the pursuit of its business
as currently conducted or then anticipated or planned (hereinafter, "Business
Opportunities")

<Page>

         (b) You shall maintain sole control and discretion as to the exact
manner of the performance of the Consulting Services, subject to the following:

             (i) The Company and you acknowledge that you currently have, and
may continue to have, a consulting arrangement with Caxton Health Holdings LLC
("CHH"), pursuant to which you will provide services to CHH that include
identifying potential technologies and related opportunities for investment and
development by CHH ("Investment Opportunities"). The Company and you further
acknowledge that, upon occasion, an Investment Opportunity that you identify may
also constitute a Business Opportunity for the Company. You hereby agree that,
if you identify or become aware of any Investment Opportunity that also
constitutes a Business Opportunity for the Company, you will endeavor first to
bring such Business Opportunity to the attention of the Company, by
communicating such opportunity to the Company's Chief Executive Officer,
providing the Company with information reasonably available to you about the
Business Opportunity, and assisting the Company, to the extent requested, in
evaluating the Business Opportunity. Such actions shall hereinafter be referred
to as providing the Company with a "Right of First Evaluation". If, however, in
any instance you believe that it would violate your obligations to CHH if you
were to provide the Company a Right of First Evaluation with respect to a
Business Opportunity that also constitutes and Investment Opportunity, you agree
to promptly notify the Company of such circumstances.

             (ii) You shall satisfy all reasonable deadlines, specifications and
requirements set forth by the Company (in consultation with you).

             (iii) In performing the Consulting Services under this Agreement,
you will (a) use diligent efforts and professional skills and judgment, (b)
perform professional services in accordance with recognized industry standards;
and (c) comply with the Company's policies applicable to consultants, members of
the Scientific Advisory Board, and other personnel and Company representatives,
as in effect from time to time. You also shall comply with all federal, state
and local employment, labor and taxation laws, regulations and rules relating to
the Consulting Services to be performed by you.

         2. TERM. This Agreement shall continue until such time as it is
terminated by you or by the Company (for any reason or no reason at all), in
either case by written notice at least fifteen (15) days in advance (the
"Consulting Term").

         3. COMPENSATION.

                  (a) CONSULTING FEES. While you continue to provide Consulting
         Services to the Company, you will be paid a consulting fee of
         Twenty-Five Thousand Dollars ($25,000.00) per month (the "Consulting
         Fee"). Consulting Fees will be paid to you no later than fifteen (15)
         days following the last day of the month during which such Consulting
         Fees are earned.

                                       2
<Page>

                  (b) REIMBURSEMENT OF EXPENSES. Upon presentation of
         documentation of such expenses reasonably satisfactory to the Company,
         the Company will reimburse you for all ordinary and reasonable
         out-of-pocket business expenses that are reasonably incurred by you in
         furtherance of the Company's business in accordance with the Company's
         policies with respect thereto as in effect from time to time.

         4. TERMINATION. Upon termination of your service to the Company for any
reason or no reason, you shall receive payment of (a) your accrued, but unpaid,
Consulting Fees through the date of termination of your service to the Company
(the "Termination Date"), and (b) all expense reimbursements due to you through
the Termination Date in accordance with established Company policies or
applicable law.

         5. PROHIBITED COMPETITION.

                  (a) CERTAIN ACKNOWLEDGEMENTS AND AGREEMENTS.

                           (i) We have discussed, and you recognize and
                  acknowledge the competitive and proprietary aspects of the
                  business of the Company Group.

                           (ii) You acknowledge that a business will be deemed
                  "competitive" with the Company Group if, at the time you enter
                  into a relationship with such business or, at any time within
                  two years thereafter while you have a relationship with such
                  business, it engages in, or is actively planning or
                  developing, any service and/or the research, development or
                  commercialization of any product that is the functional
                  equivalent of, or that has or will likely have the effect of
                  materially displacing sales of services or products which (A)
                  are performed, produced, manufactured, distributed, sold,
                  under research or active development or in active planning by
                  the Company Group at any time while you are providing
                  Consulting Services or (B) are expressly identified in writing
                  as the subject of your Consulting Services hereunder. If the
                  Company requests that you provide Consulting Services that you
                  advise the Company may be competitive with the activities of
                  another business with which you then have a relationship, the
                  Company may at its option (x) terminate the Consulting
                  Services and in connection therewith pay to you any fees and
                  reimbursable expenses due for all Consulting Services rendered
                  through the date of termination, or (y) require you to
                  terminate your services with the competitive business or
                  entity.

                           (iii) You further acknowledge that, while you perform
                  Consulting Services hereunder, the Company Group will furnish,
                  disclose or make available to you Confidential Information (as
                  defined below) related to the business of the Company Group
                  and that the Company Group. You also acknowledge that such
                  Confidential Information has been developed and will be
                  developed by the Company Group through the expenditure by the
                  Company Group of substantial time, effort and money and that
                  all such Confidential Information could be used by you to
                  compete with the Company Group. Further, while you perform
                  Consulting Services hereunder, you will be introduced to
                  customers and others with important relationships to the
                  Company Group. You acknowledge that any

                                       3
<Page>

                  and all "goodwill" created through such introductions belongs
                  exclusively to the Company Group, including, without
                  limitation, any goodwill created as a result of direct or
                  indirect contacts or relationships between yourself and any
                  customers or other third parties doing business with the
                  Company Group.

                           (iv) For purposes of this Agreement, "Confidential
                  Information" means confidential and proprietary information of
                  the Company Group, whether in written, oral, electronic or
                  other form, including but not limited to, information and
                  facts concerning business plans; current or potential
                  customers, suppliers, licensors, licensees, partners,
                  investors, affiliates or others; training methods and
                  materials; financial information; sales prospects; client
                  lists; inventions; or any other scientific, technical or trade
                  secrets of the Company Group or of any third party provided to
                  you or the Company Group under a condition of confidentiality;
                  provided that Confidential Information will not include
                  information that is in the public domain other than through
                  any fault or act by you. The term "trade secrets," as used in
                  this Agreement, will be given its broadest possible
                  interpretation under the law of the Commonwealth of
                  Massachusetts and will include, without limitation, anything
                  tangible or intangible or electronically kept or stored, which
                  constitutes, represents, evidences or records secret,
                  scientific, technical, merchandising, production or management
                  information, or any design, process, procedure, formula,
                  invention, improvement or other confidential or proprietary
                  information or documents.

                  (b) NON-COMPETITION; NON-SOLICITATION. While you perform
         Consulting Services hereunder and for a period of one year following
         the termination of your service to the Company Group hereunder for any
         reason or for no reason, you will not, without the prior written
         consent of the Company:

                           (i) For yourself or on behalf of any other person or
                  entity, directly or indirectly, either as principal, partner,
                  stockholder, officer, director, member, employee, consultant,
                  agent, representative or in any other capacity, own, manage,
                  operate or control, or be concerned, connected or employed by,
                  or otherwise associate in any manner with, engage in or have a
                  financial interest in, any business which is competitive with
                  the business of the Company Group (each, a "Restricted
                  Activity") anywhere in the world, except that (A) nothing
                  contained herein will preclude you from purchasing or owning
                  securities of any such business if such securities are
                  publicly traded, and provided that your holdings do not exceed
                  one percent of the issued and outstanding securities of any
                  class of securities of such business and (B) nothing contained
                  herein will prohibit you from engaging in a Restricted
                  Activity for or with respect to any subsidiary, division or
                  affiliate or unit (each, a "Unit") of an entity if that Unit
                  is not engaged in any business which is competitive with the
                  business of the Company Group, irrespective of whether some
                  other Unit of such entity engages in such competition (as long
                  as you do not engage in a Restricted Activity for such other
                  Unit); or

                           (ii) Either individually or on behalf of or through
                  any third party, directly or indirectly, solicit, divert or

                                       4
<Page>

                  appropriate or attempt to solicit, divert or appropriate, for
                  the purpose of competing with the Company Group, any
                  customers, licensors, licensees, collaborative partners, or
                  other patrons of the Company Group, or any such person or
                  entity with respect to which the Company Group has developed
                  or made a presentation (or similar communication) with a view
                  to developing a business relationship;

                           (iii) Either individually or on behalf of or through
                  any third party, directly or indirectly, (A) solicit, entice
                  or persuade or attempt to solicit, entice or persuade any
                  employee of or consultant to the Company Group to leave the
                  service of the Company Group for any reason, or (B) employ,
                  cause to be employed, or solicit the employment of, any
                  employee of or consultant to the Company Group while any such
                  person is providing services to the Company Group or within
                  six months after any such person has ceased providing services
                  to the Company Group; or

                           (iv) Either individually or on behalf of or through
                  any third party, directly or indirectly, interfere with, or
                  attempt to interfere with, the relations between the Company
                  Group and any licensor, licensee, collaborative partner,
                  customer, vendor or supplier to the Company Group.

                  (c) REASONABLENESS OF RESTRICTIONS. You further recognize and
         acknowledge that (i) the types of employment which are prohibited by
         this Section 5 are narrow and reasonable in relation to the skills
         which represent your principal salable asset both to the Company Group
         and to others and (ii) the time period and the geographical scope of
         the provisions of this Section 5 is reasonable, legitimate and fair to
         you in light of the Company Group's need to effectively pursue its
         business plan and objectives and in light of the limited restrictions
         on the type of activities prohibited herein compared to the types of
         activities for which you are qualified to earn your livelihood.

                  (d) SURVIVAL OF ACKNOWLEDGEMENTS AND AGREEMENTS. Your
         acknowledgements and agreements set forth in this Section 5 will
         survive the termination of this Agreement and the termination of your
         services hereunder for any reason or for no reason.

                  (e) ACKNOWLEDGEMENT REGARDING CHH AFFILIATION. The Company
         acknowledges that your affiliation with CHH is not in violation of this
         Agreement, provided that you (i) maintain the confidentiality of all
         Confidential Information as required by this Agreement, (ii) may not
         engage in a competitive Restricted Activity, individually or in concert
         with others, in connection with your affiliation with CHH, and (iii)
         abide by your obligations set out in Section 1(b)(i) hereof.

         6. PROTECTED INFORMATION. You will at all times, both during the period
while you perform Consulting Services hereunder and after the termination of
this Agreement and the termination of your service to the Company hereunder for
any reason or for no reason, maintain in confidence and will not, without the
prior written consent of the Company Group, use, except as required in the
course of performance of your duties for the Company Group or by court order,
disclose or give to others any Confidential Information. In the event you are
questioned

                                       5
<Page>

by anyone not employed by the Company or by an employee of or a consultant to
the Company not authorized to receive Confidential Information, in regard to any
Confidential Information, or concerning any fact or circumstance relating
thereto, you will promptly notify the Company. Upon the termination of your
service to the Company hereunder for any reason or for no reason, or if the
Company Group otherwise requests, you will return to the Company Group all
tangible Confidential Information and copies thereof (regardless how such
Confidential Information or copies are maintained). The terms of this Section 6
are in addition to, and not in lieu of, any statutory or other contractual or
legal obligation that you may have relating to the protection of the Company
Group's Confidential Information. The terms of this Section 6 will survive
indefinitely any termination of this Agreement and/or any termination of your
service to the Company Group hereunder for any reason or for no reason.

         7. OWNERSHIP OF IDEAS, COPYRIGHTS AND PATENTS.

                  (a) PROPERTY OF THE COMPANY. All ideas, discoveries,
         creations, manuscripts and properties, innovations, improvements,
         know-how, inventions, designs, developments, apparatus, techniques,
         methods, biological processes, cell lines, laboratory notebooks and
         formulae in any form known or not yet known throughout the world
         (collectively, the "Inventions") which may be used or useful in the
         current or planned business of the Company Group or which in any way
         relates to such business, whether patentable, copyrightable or not,
         which you may conceive, reduce to practice or develop arising out of or
         in connection with your performance of Consulting Services hereunder
         (and, if based on or related to any Confidential Information, within
         one year after termination of such service to the Company Group for any
         reason or for no reason), alone or in conjunction with another or
         others, whether during or out of regular business hours, whether or not
         on the Company Group's premises or with the use of its equipment, and
         whether at the request or upon the suggestion of the Company Group or
         otherwise, will be the sole and exclusive property of the Company
         Group, and you will not publish any of the Inventions without the prior
         written consent of the Company Group. Without limiting the foregoing,
         you also acknowledge that all original works of authorship which are
         made by you (solely or jointly with others) within the scope of your
         services to the Company or which relate to the business of the Company
         Group and which are protectable by copyright are "works made for hire"
         pursuant to the United States Copyright Act (17 U.S.C. Section 101).
         You hereby assign to the Company Group all of your right, title and
         interest in and to all of the foregoing. You further represent that, to
         the best of your knowledge and belief, none of the Inventions will
         violate or infringe upon any right, patent, copyright, trademark or
         right of privacy, or constitute libel or slander against or violate any
         other rights of any person, firm or corporation, and that you will not
         knowingly create any Invention which causes any such violation.

                  (b) COOPERATION. At any time during your service to the
         Company hereunder or after the termination of your service to the
         Company hereunder for any reason or for no reason, you will cooperate
         fully with the Company Group and its attorneys and agents in the
         preparation and filing of all papers and other documents as may be
         required to perfect the Company Group's rights in and to any of such
         Inventions, including, but not limited to, joining in any proceeding to
         obtain letters patent, copyrights, trademarks or other legal rights
         with respect to any such Inventions in the United States and in any and

                                       6
<Page>

         all other countries, provided that the Company Group will bear the
         expense of such proceedings and, if after the termination of your
         services to the Company Group hereunder, shall compensate you at your
         then current per diem rate for your time spent providing such
         cooperation and assistance, as evidenced by time records in reasonable
         detail submitted to the Company. Any patent or other legal right so
         issued to you personally will be assigned by you to the Company Group
         without charge by you.

                  (c) LICENSING AND USE OF INVENTIONS. With respect to any
         Inventions, whenever created, which you have not prepared or originated
         in the performance of your services to the Company Group, but which you
         provide to the Company Group or incorporate in any Company Group
         product or system, you hereby grant to the Company Group a
         royalty-free, fully paid-up, non-exclusive, perpetual and irrevocable
         license throughout the world to use, modify, create derivative works
         from, disclose, publish, translate, reproduce, deliver, perform,
         dispose of, and to authorize others so to do, all such Inventions. You
         will not include in any Inventions you deliver to the Company Group or
         use on its behalf, without the prior written approval of the Company
         Group, any material which is or will be patented, copyrighted or
         trademarked by you or others unless you provide the Company Group with
         the written permission of the holder of any patent, copyright or
         trademark owner for the Company Group to use such material in a manner
         consistent with then-current Company Group policy.

                  (d) PRIOR INVENTIONS. Listed on EXHIBIT 7(d) to this Agreement
         are any and all Inventions in which you claim or intend to claim any
         right, title and interest (collectively, "Prior Inventions"),
         including, without limitation, patent, copyright and trademark
         interests, which to the best of your knowledge will be or may be
         delivered to the Company Group in the course of your service to the
         Company, or incorporated into any Company Group product or system. You
         acknowledge that your obligation to disclose such information is
         ongoing while you perform Consulting Services hereunder.

         8. DISCLOSURE TO FUTURE EMPLOYERS. You will provide, and the Company,
in its discretion, may similarly provide, a copy of the covenants contained in
Sections 5, 6 and 7 of this Agreement to any business or enterprise which you
may, directly or indirectly, own, manage, operate, finance, join, control or in
which you may participate in the ownership, management, operation, financing, or
control, or with which you may be connected as an officer, director, employee,
partner, principal, agent, representative, consultant or otherwise.

         9. RECORDS. Upon termination of your services to the Company Group
hereunder for any reason or for no reason and at any other time requested by the
Company Group, you will deliver to the Company Group any property of the Company
Group which may be in your possession, including products, materials, memoranda,
notes, records, reports, or other documents or photocopies of the same
(regardless of how they are maintained, including whether or not they are in
electronic form).

         10. INSURANCE. While you are performing Consulting Services to the
Company Group hereunder, you shall be solely responsible for securing, paying
for and maintaining any insurances, licenses and/or permits necessary to perform
any of the Consulting Services required under this Agreement, including, but not
limited to, general liability insurance (bodily injury and

                                       7
<Page>

property damage), professional liability insurance and workers' compensation
insurance. Upon request, you will furnish to the Company all applicable
certificates of insurance contemplated by this section.

         11. INDEPENDENT CONTRACTOR STATUS. You and the Company agree that your
Consulting Services are made available to the Company Group on the basis that
you will retain your individual professional status and that your relationship
with the Company Group is that of an independent contractor and not that of an
employee. You acknowledge will not be eligible for any employee benefits, nor
will the Company make deductions from its fees to you for taxes, insurance,
bonds or any other subscription of any kind. The Company will record payments to
you on, and provide to you, an Internal Revenue Service Form 1099, and the
Company will not withhold any employment taxes on your behalf. Payment of all
federal, state and local income, employment and other taxes (including
unemployment insurance, social security taxes and federal, state and local
withholding taxes) are your sole responsibility. You will indemnify and hold
harmless the Company Group and its officers, directors, security holders,
partners, members, employees, agents and representatives against loss, damage,
liability or expense arising from any claim based on your failure to pay any or
all taxes due from you to any applicable taxing authorities.

         12. REPRESENTATIONS AND ACKNOWLEDGEMENTS. You hereby represent and
warrant to the Company that you understand this Agreement, that you enter into
this Agreement voluntarily and that your service to the Company Group under this
Agreement will not conflict with any legal duty owed by you to any other party,
or with any agreement to which you are a party or by which you are bound,
including, without limitation, any non-competition or non-solicitation provision
contained in any such agreement. You will indemnify and hold harmless the
Company Group and its officers, directors, security holders, partners, members,
employees, agents and representatives against loss, damage, liability or expense
arising from any claim based upon circumstances alleged to be inconsistent with
such representation and warranty.

         13. GENERAL.

                  (a) NOTICES. All notices, requests, consents and other
         communications hereunder which are required to be provided, or which
         the sender elects to provide, in writing, will be addressed to the
         receiving party's address set forth above or to such other address as a
         party may designate by notice hereunder, and will be either (i)
         delivered by hand, (ii) sent by overnight courier, or (iii) sent by
         registered or certified mail, return receipt requested, postage
         prepaid. All notices, requests, consents and other communications
         hereunder will be deemed to have been given either (i) if by hand, at
         the time of the delivery thereof to the receiving party, (ii) if sent
         by overnight courier, on the next business day following the day such
         notice is delivered to the courier service, or (iii) if sent by
         registered or certified mail, on the fifth business day following the
         day such mailing is made.

                  (b) ENTIRE AGREEMENT.

                     (i) It is hereby acknowledged that the Company an you have
         entered into an Agreement and Release, dated January 14, 2005 (the
         "Agreement and Release"), arising out of your services to the Company,
         its Affiliates and Predecessors (as such terms

                                       8
<Page>

         are defined therein) during the period prior to the date hereof. The
         Company and you hereby acknowledge and agree that certain provisions of
         the Agreement and Release (E.G., the confidentiality, non-competition,
         non-solicitation and inventions assignment provisions) are
         substantially the same as corresponding provisions of this Agreement,
         except that such provisions of the Agreement and Release are intended
         to be effective and apply to matters arising out of the period of your
         services to the Company, its Affiliates and Predecessors prior to the
         date of this Agreement, and the corresponding provisions of this
         Agreement are intended to be effective and apply to matters arising out
         of the period commencing on the date hereof. The parties agree that
         this Agreement shall not be deemed to supersede the Agreement and
         Release except if, and to the extent that, (A) a provision of this
         Agreement contains substantially equivalent terms to a corresponding
         provision of the Agreement and Release, and (B) the application of such
         provision of this Agreement alone (I.E., without continued
         effectiveness and application of the corresponding provision of the
         Agreement and Release) will provide the same protection to the Company
         Group as would be the case if both the provision in this Agreement and
         the corresponding provision in the Agreement and Release continued to
         be effective and apply. All other terms and provisions of the Agreement
         and Release shall continue in full force and effect.

                     (ii) Subject to subparagraph (i) above, this Agreement,
         together with the other agreements specifically referred to herein,
         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 of any kind not expressly set forth in this Agreement will
         affect, or be used to interpret, change or restrict, the express terms
         and provisions of this Agreement.

                  (c) MODIFICATIONS AND AMENDMENTS. The terms and provisions of
         this Agreement may be modified or amended only by written agreement
         executed by the parties hereto.

                  (d) WAIVERS AND CONSENTS. 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 will be
         deemed to be or will 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 will be effective only in the specific
         instance and for the purpose for which it was given, and will not
         constitute a continuing waiver or consent.

                  (e) ASSIGNMENT. The Company may assign its rights and
         obligations hereunder to any person or entity that succeeds to all or
         substantially all of the Company's business or that aspect of the
         Company's business in which you are principally involved, or to any
         Company Affiliate. You may not assign your rights and obligations under
         this Agreement without the prior written consent of the Company, and
         any such attempted assignment by you without the prior written consent
         of the Company will be void.

                  (f) BENEFIT. All statements, representations, warranties,
         covenants and agreements in this Agreement will be binding on the
         parties hereto and will inure to the

                                       9
<Page>

         benefit of the respective successors and permitted assigns of each
         party hereto. Nothing in this Agreement will be construed to create any
         rights or obligations except between the Company and you, except for
         your obligations to the Company Group as set forth herein, and no
         person or entity (except for a Company Affiliate as set forth herein)
         will be regarded as a third-party beneficiary of this Agreement.

                  (g) GOVERNING LAW. This Agreement and the rights and
         obligations of the parties hereunder will be construed in accordance
         with and governed by the law of the Commonwealth of Massachusetts,
         without giving effect to the conflict of law principles thereof.

                  (h) JURISDICTION, VENUE AND SERVICE OF PROCESS. Any legal
         action or proceeding with respect to this Agreement that is not subject
         to arbitration pursuant to Section 13(i) below will be brought in the
         courts of the Commonwealth of Massachusetts or of the United States of
         America for the District of Massachusetts. By execution and delivery of
         this Agreement, each of the parties hereto accepts for itself and in
         respect of its property, generally and unconditionally, the exclusive
         jurisdiction of the aforesaid courts.

                  (i) ARBITRATION. Any controversy, dispute or claim arising out
         of or in connection with this Agreement, other than a controversy,
         dispute or claim arising under Section 5, 6 or 7 hereof, will be
         settled by final and binding arbitration to be conducted in Boston,
         Massachusetts pursuant to the national rules for the resolution of
         employment disputes of the American Arbitration Association then in
         effect. The decision or award in any such arbitration will be final and
         binding upon the parties and judgment upon such decision or award may
         be entered in any court of competent jurisdiction or application may be
         made to any such court for judicial acceptance of such decision or
         award and an order of enforcement. In the event that any procedural
         matter is not covered by the aforesaid rules, the procedural law of
         Massachusetts will govern. Any disagreement as to whether a particular
         dispute is arbitrable under this Agreement shall itself be subject to
         arbitration in accordance with the procedures set forth herein.

                  (j) WAIVER OF JURY TRIAL. ANY ACTION, DEMAND, CLAIM OR
         COUNTERCLAIM ARISING UNDER OR RELATING TO THIS AGREEMENT THAT IS NOT
         SUBJECT TO ARBITRATION PURSUANT TO SECTION 13(i) ABOVE WILL BE RESOLVED
         BY A JUDGE ALONE AND EACH OF YOU AND THE COMPANY WAIVE ANY RIGHT TO A
         JURY TRIAL THEREOF.

                  (k) SEVERABILITY. The parties intend this Agreement to be
         enforced as written. However, (i) if any portion or provision of this
         Agreement is to any extent declared illegal or unenforceable by a duly
         authorized court having jurisdiction, then the remainder of this
         Agreement, or the application of such portion or provision in
         circumstances other than those as to which it is so declared illegal or
         unenforceable, will not be affected thereby, and each portion and
         provision of this Agreement will be valid and enforceable to the
         fullest extent permitted by law and (ii) if any provision, or part
         thereof, is held to be unenforceable because of the duration of such
         provision, the geographic area covered thereby, or other aspect or
         scope of such provision, the court making such determination will have
         the power to reduce the duration, geographic area of such provision, or
         other aspect or scope of such

                                       10
<Page>

         provision, and/or to delete specific words and phrases
         ("blue-penciling"), and in its reduced or blue-penciled form, such
         provision will then be enforceable and will be enforced.

                  (l) HEADINGS AND CAPTIONS. The headings and captions of the
         various subdivisions of this Agreement are for convenience of reference
         only and will in no way modify or affect the meaning or construction of
         any of the terms or provisions hereof.

                  (m) INJUNCTIVE RELIEF. You hereby expressly acknowledge that
         any breach or threatened breach of any of the terms and/or conditions
         set forth in Section 5, 6 or 7 of this Agreement will result in
         substantial, continuing and irreparable injury to the Company Group.
         Therefore, in addition to any other remedy that may be available to the
         Company Group, the Company Group will be entitled to injunctive or
         other equitable relief by a court of appropriate jurisdiction in the
         event of any breach or threatened breach of the terms of Section 5, 6
         or 7 of this Agreement. The period during which the covenants contained
         in Section 5 will apply will be extended by any periods during which
         you are found by a court to have been in violation of such covenants.

                  (n) NO WAIVER OF RIGHTS, POWERS AND REMEDIES. No failure or
         delay by a party hereto in exercising any right, power or remedy under
         this Agreement, and no course of dealing between the parties hereto,
         will operate as a waiver of any such right, power or remedy of the
         party. No single or partial exercise of any right, power or remedy
         under this Agreement by a party hereto, nor any abandonment or
         discontinuance of steps to enforce any such right, power or remedy,
         will preclude such party from any other or further exercise thereof or
         the exercise of any other right, power or remedy hereunder. The
         election of any remedy by a party hereto will not constitute a waiver
         of the right of such party to pursue other available remedies. No
         notice to or demand on a party not expressly required under this
         Agreement will entitle the party receiving such notice or demand to any
         other or further notice or demand in similar or other circumstances or
         constitute a waiver of the rights of the party giving such notice or
         demand to any other or further action in any circumstances without such
         notice or demand.

                  (o) COUNTERPARTS. This Agreement may be executed in two or
         more counterparts, and by different parties hereto on separate
         counterparts, each of which will be deemed an original, but all of
         which together will constitute one and the same instrument.

                  (p) OPPORTUNITY TO REVIEW. You hereby acknowledge that you
         have had adequate opportunity to review these terms and conditions and
         to reflect upon and consider the terms and conditions of this
         Agreement, and that you have had the opportunity to consult with
         counsel of your own choosing regarding such terms. You further
         acknowledge that you fully understand the terms of this Agreement and
         have voluntarily executed this Agreement.

                                       11
<Page>

         If the foregoing accurately sets forth our agreement, please so
indicate by signing and returning to us the enclosed copy of this Agreement.

                                        Very truly yours,

                                        SYNTA PHARMACEUTICALS CORP.

                                        By: /s/ Safi R. Bahcall
                                            -----------------------------------
                                            Safi R. Bahcall, Ph.D.
                                            President and Chief Executive
                                            Officer

Accepted and Approved:

/s/ Lan Bo Chen                        April 18, 2005
----------------------------------     ----------------------------------
Lan Bo Chen, Ph.D.                     Date

                                       12

<Page>

                                  EXHIBIT 7(d)

                                PRIOR INVENTIONS

                                       13

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