Exhibit 10.28

RESTRICTED STOCK AGREEMENT

AGREEMENT made this 6th day of October 2003, between Infinity Pharmaceuticals,
Inc., a Delaware corporation (the “Company”), and Julian Adams (the
“Participant”).

For valuable consideration, receipt of which is acknowledged, the parties hereto
agree as follows:

1. Purchase of Shares. The Company shall issue and sell to the Participant and
the Participant shall purchase from the Company, subject to the terms and
conditions set forth in this Agreement and in the Company’s 2001 Stock Incentive
Plan (the “Plan”), an aggregate of 750,000 shares (the “Shares”) of common
stock, $.0001 par value per share (“Common Stock”) of the Company at a price of
$0.38 per share (the “Option Price”), purchasable as set forth in and subject to
the terms and conditions of this Agreement and the Plan.

The aggregate purchase price for the Shares shall be paid by the Participant by
delivery of a promissory note (the “Note”) of the Participant in the form
attached hereto as Exhibit A (except that the aggregate par value of the Shares
shall be paid by the Participant by check payable to the Company). Upon receipt
of payment by the Company for the Shares, the Company shall issue to the
Participant one or more certificates in the name of the Participant for that
number of Shares purchased by the Participant. The Participant agrees that the
Shares shall be subject to the Purchase Option set forth in Section 2 of this
Agreement and the restrictions on transfer set forth in Sections 4 and 5 of this
Agreement.

2. Purchase Option.

(a) In the event that the Participant ceases to be employed by the Company for
any reason or no reason, with or without cause, prior to October 6, 2007, the
Company shall have the right and option (the “Purchase Option”) to purchase from
the Participant, for a sum equal to the Option Price per share, any shares then
subject to the Purchase Option. All of the Shares shall be subject to the
Purchase Option prior to October 6, 2004. On October 6, 2004, one-fourth (l/4th)
of such Shares will no longer be subject to the Purchase Option and at the end
of each full month thereafter, one forty-eighth (l/48th) of such Shares shall no
longer be subject to the Purchase Option until such time as all of such Shares
are no longer subject to the Purchase Option. The Shares that are subject to the
Purchase Option are referred to hereon as the “Unvested Shares” and the Shares
that are no longer subject to the Purchase Option are referred to hereby as the
“Vested Shares.”

(b) Notwithstanding paragraph (a) above, in the event that the Participant’s
employment is terminated by the Company without Cause (as defined below) or the
Participant resigns for Good Reason (as defined below), then, subject to the
Participant entering into a severance agreement and general release of claims,
in a form acceptable to the Company,, the Participant shall be deemed to have
completed an additional six (6) months of employment for purposes of calculating
the number of Shares that remain subject to the Purchase Option.

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(c) As used herein, “Cause” for termination shall be deemed to exist upon
(a) good faith finding by the Board of Directors of the Company of (i) failure
of the Participant to perform his material duties as an employee of the Company
in a manner acceptable to the Company, which failure continues for a period of
more than thirty (30) days after the Company has provided the Participant with
notice thereof has been provided to you in writing by the Company, setting forth
in reasonable detail the nature of such failure or (ii) the commission by the
Participant of acts of dishonesty; gross negligence or misconduct; or (b) the
conviction of the Participant of, or the entry of a pleading of guilty or nolo
contendere by the Participant to, any felony or any crime involving extortion,
dishonesty, or theft.

(d) As used herein, “Good Reason” for resignation shall be deemed to exist if
the Participant resigns due to (a) a material diminution in the Participant’s
job responsibilities or titles or (b) the Company materially breaching an
employment contract with the Participant, including the Offer Letter between the
Company and the Participant dated August 19, 2003.

3. Exercise of Purchase Option and Closing.

(a) The Company may exercise the Purchase Option by delivering or mailing to the
Participant (or his estate), in accordance with Section 10(e) within 90 days
after the termination of the employment of the Participant with the Company, a
written notice of exercise of the Purchase Option. Such notice shall specify the
number of Shares to be purchased. If and to the extent the Purchase Option is
not so exercised by the giving of such a notice within such 90-day period, the
Purchase Option shall automatically expire and terminate effective upon the
expiration of such 90-day period.

(b) Within 10 days after his receipt of the Company’s notice of the exercise of
the Purchase Option pursuant to subsection (a) above, the Participant (or his
estate or any escrow agent) shall tender to the Company at its principal offices
the certificate or certificates representing the Shares which the Company has
elected to purchase, duly endorsed in blank by the Participant or with duly
endorsed stock powers attached thereto, all in form suitable for the transfer of
such Shares to the Company. Upon its receipt of such certificate or
certificates, the Company shall pay the aggregate Option Price therefor in the
form of a check or by canceling indebtedness owed by the Participant to the
Company, or any combination thereof.

(c) After the time at which any Shares are required to be delivered to the
Company for transfer to the Company pursuant to subsection (b) above, the
Company shall not pay any dividend to the Participant on account of such Shares
or permit the Participant to exercise any of the privileges or rights of a
stockholder with respect to such Shares, but shall, in so far as permitted by
law, treat the Company as the owner of such Shares.

(d) In the event that, due to the sale (whether by foreclosure or otherwise),
transfer, assignment or other disposition of the Shares (other than pursuant to
the Company’s exercise of the Purchase Option), including, without limitation, a
sale by the Company or any assignee of the Shares pursuant to the terms of the
Note (each, a “Sale Event”), the Company is unable to exercise the Purchase
Option with respect to any Shares for which the Purchase Option has not
terminated (the “Repurchase Shares”), the Participant agrees to pay the Company,
as liquidated damages, a sum, if any, by which the market value of the
Repurchase Shares (as

 

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determined by such Sale Event) exceeds the aggregate Option Price paid for the
Repurchase Shares (the “Damage Amount”).

(e) The Option Price may be payable, at the option of the Company, in
cancellation of all or a portion of any outstanding indebtedness of the
Participant to the Company or in cash (by check) or both.

(f) The Company shall not purchase any fraction of a Share upon exercise of the
Purchase Option, and any fraction of a Share resulting from a computation made
pursuant to Section 2 of this Agreement shall be rounded to the nearest whole
Share (with any one-half Share being rounded upward).

4. Restrictions on Transfer.

(a) The Participant shall not sell, assign, transfer, pledge, hypothecate or
otherwise dispose of, by operation of law or otherwise (collectively “transfer”)
any Shares, or any interest therein, that are subject to the Purchase Option,
except that the Participant may (i) transfer such Shares to or for the benefit
of any spouse, domestic partner sharing the same household as the Participant,
sibling, child or grandchild, or to a trust for the benefit of the Participant
or any of such family member’s benefit (an “Approved Relative”), provided that
such Shares shall remain subject to this Agreement (including without limitation
the restrictions on transfer set forth in this Section 4, the Purchase Option,
and the right of first refusal set forth in Section 5) and such permitted
transferee shall, as a condition to such transfer, deliver to the Company a
written instrument confirming that such transferee shall be bound by all of the
terms and conditions of this Agreement, (ii) transfer such Shares as part of the
sale of all or substantially all of the shares of capital stock of the Company
(including pursuant to a merger or consolidation), provided that, in accordance
with the Plan, the securities or other property received by the Participant in
connection with such transaction shall remain subject to this Agreement, or
(iii) pledge to the Company pursuant to the Note such Shares to secure payment
of part or all of the purchase price of such Shares.

(b) The Participant shall not transfer any Shares, or any interest therein, that
are no longer subject to the Purchase Option, except in accordance with
Section 5 below.

5. Right of First Refusal.

(a) If the Participant proposes to transfer any Shares that are no longer
subject to the Purchase Option, then the Participant shall first give written
notice of the proposed transfer (the “Transfer Notice”) to the Company. The
Transfer Notice shall name the proposed transferee and state the number of such
Shares he proposes to transfer (the “Offered Shares”), the price per share and
all other material terms and conditions of the transfer.

(b) For 30 days following delivery to the Company of such Transfer Notice, the
Company shall have the option to purchase all (but not less than all) of the
Offered Shares at the price and upon the terms set forth in the Transfer Notice,
hi the event the Company elects to purchase all of the Offered Shares, it shall
give written notice of such election to the Participant within such 30-day
period. Within 10 days after delivery to the Participant of such notice, the
Participant shall tender to the Company at its principal offices the certificate
or certificates

 

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representing the Offered Shares, duly endorsed in blank by the Participant or
with duly endorsed stock powers attached thereto, all in form suitable for
transfer of the Offered Shares to the Company. Promptly following receipt of
such certificate or certificates, the Company shall deliver or mail to the
Participant a check in payment of the purchase price for the Offered Shares;
provided that if the terms of payment set forth in the Transfer Notice were
other than cash against delivery, the Company may pay for the Offered Shares on
the same terms and conditions as were set forth in the Transfer Notice; and
provided further that any delay in making such payment shall not invalidate the
Company’s exercise of its option to purchase the Offered Shares.

(c) If the Company does not elect to acquire all of the Offered Shares, the
Participant may, within the 30-day period following the expiration of the option
granted to the Company under subsection (b) above, transfer the Offered Shares
to the proposed transferee, provided that such transfer shall not be on terms
and conditions more favorable to the transferee than those contained in the
Transfer Notice. Notwithstanding any of the above, all Offered Shares
transferred pursuant to this Section 5 shall remain subject to this Agreement
(including without limitation the restrictions on transfer set forth in
Section 4 and the right of first refusal set forth in this Section 5) and such
transferee shall, as a condition to such transfer, deliver to the Company a
written instrument confirming that such transferee shall be bound by all of the
terms and conditions of this Agreement.

(d) After the time at which the Offered Shares are required to be delivered to
the Company for transfer to the Company pursuant to subsection (b) above, the
Company shall not pay any dividend to the Participant on account of such Offered
Shares or permit the Participant to exercise any of the privileges or rights of
a stockholder with respect to such Shares, but shall, in so far as permitted by
law, treat the Company as the owner of such Offered Shares.

(e) The following transactions shall be exempt from the provisions of this
Section 5:

(i) a transfer of Shares to or for the benefit of any Approved Relatives, or to
a trust established solely for the benefit of the Participant and/or Approved
Relatives;

(ii) any transfer pursuant to an effective registration statement filed by the
Company under the Securities Act of 1933, as amended (the “Securities Act”); and

(iii) the sale of all or substantially all of the shares of capital stock of the
Company (including pursuant to a merger or consolidation),

provided, however, that in the case of a transfer pursuant to clause (i) above,
such Shares shall remain subject to this Agreement (including without limitation
the restrictions on transfer set forth in Section 4 and the right of first
refusal set forth in this Section 5) and such transferee shall, as a condition
to such transfer, deliver to the Company a written instrument confirming that
such transferee shall be bound by all of the terms and conditions of this
Agreement.

 

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(f) The Company may assign its rights to purchase Offered Shares in any
particular transaction under this Section 5 to one or more persons or entities.

(g) The provisions of this Section 5 shall terminate upon the earlier of the
following events:

(i) the closing of the sale of shares of Common Stock in an underwritten public
offering pursuant to an effective registration statement filed by the Company
under the Securities Act; or

(ii) the sale of all or substantially all of the capital stock, assets or
business of the Company, by merger, consolidation, sale of assets or otherwise
(other than a merger or consolidation in which all or substantially all of the
individuals and entities who were beneficial owners of the Common Stock
immediately prior to such transaction beneficially own, directly or indirectly,
more than 75% of the outstanding securities entitled to vote generally in the
election of directors of the resulting, surviving or acquiring corporation in
such transaction).

(h) The Company shall not be required (i) to transfer on its books any of the
Shares which shall have been sold or transferred in violation of any of the
provisions set forth in this Agreement, or (ii) to treat as owner of such Shares
or to pay dividends to any transferee to whom any such Shares shall have been so
sold or transferred.

6. Agreement in Connection with Public Offering.

The Participant agrees, in connection with the initial underwritten public
offering of the Company’s securities pursuant to a registration statement under
the Securities Act, (i) not to sell, make short sale of, loan, grant any options
for the purchase of, or otherwise dispose of any shares of Common Stock held by
the Participant (other than those shares included in the offering) without the
prior written consent of the Company or the underwriters managing such initial
underwritten public offering of the Company’s securities for a period of 180
days from the effective date of such registration statement, and (ii) to execute
any agreement reflecting clause (i) above as may be requested by the Company or
the managing underwriters at the time of such offering.

7. Restrictive Legends.

All certificates representing Shares shall have affixed thereto legends in
substantially the following form, in addition to any other legends that may be
required under federal or state securities laws:

“The shares of stock represented by this certificate are subject to restrictions
on transfer and an option to purchase set forth in a certain Restricted Stock
Agreement between the corporation and the registered owner of these shares (or
his predecessor in interest), and such Agreement is available for inspection
without charge at the office of the Secretary of the corporation.”

 

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“The shares represented by this certificate have not been registered under the
Securities Act of 1933, as amended, and may not be sold, transferred or
otherwise disposed of in the absence of an effective registration statement
under such Act or an opinion of counsel satisfactory to the corporation to the
effect that such registration is not required.”

8. Investment Representations.

The Participant represents, warrants and covenants as follows:

(a) The Participant is purchasing the Shares for his own account for investment
only, and not with a view to, or for sale in connection with, any distribution
of the Shares in violation of the Securities Act, or any rule or regulation
under the Securities Act.

(b) The Participant has had such opportunity as he has deemed adequate to obtain
from representatives of the Company such information as is necessary to permit
him to evaluate the merits and risks of his investment in the Company.

(c) The Participant has sufficient experience in business, financial and
investment matters to be able to evaluate the risks involved in the purchase of
the Shares and to make an informed investment decision with respect to such
purchase.

(d) The Participant can afford a complete loss of the value of the Shares and is
able to bear the economic risk of holding such Shares for an indefinite period.

(e) The Participant understands that (i) the Shares have not been registered
under the Securities Act and are “restricted securities” within the meaning of
Rule 144 under the Securities Act; (ii) the Shares cannot be sold, transferred
or otherwise disposed of unless they are subsequently registered under the
Securities Act or an exemption from registration is then available; (iii) in any
event, the exemption from registration under Rule 144 will not be available for
at least one year and even then will not be available unless a public market
then exists for the Common Stock, adequate information concerning the Company is
then available to the public, and other terms and conditions of Rule 144 are
complied with; and (iv) there is now no registration statement on file with the
Securities and Exchange Commission with respect to any stock of the Company and
the Company has no obligation or current intention to register the Shares under
the Securities Act.

9. Withholding Taxes; Section 83(b) Election.

(a) The Participant acknowledges and agrees that the Company has the right to
deduct from payments of any kind otherwise due to the Participant any federal,
state or local taxes of any kind required by law to be withheld with respect to
the purchase of the Shares by the Participant or the lapse of the Purchase
Option.

(b) The Participant has reviewed with the Participant’s own tax advisors the
federal, state, local and foreign tax consequences of this investment and the
transactions contemplated by this Agreement. The Participant is relying solely
on such advisors and not on

 

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any statements or representations of the Company or any of its agents. The
Participant understands that the Participant (and not the Company) shall be
responsible for the Participant’s own tax liability that may arise as a result
of this investment or the transactions contemplated by this Agreement. The
Participant understands that it may be beneficial in many circumstances to elect
to be taxed at the time the Shares are purchased rather than when and as the
Company’s Purchase Option expires by filing an election under Section 83(b) of
the Code with the I.R.S. within 30 days from the date of purchase.

THE PARTICIPANT ACKNOWLEDGES THAT IT IS THE PARTICIPANT’S SOLE RESPONSIBILITY
AND NOT THE COMPANY’S TO FILE TIMELY THE ELECTION UNDER SECTION 83(b), EVEN IF
THE PARTICIPANT REQUESTS THE COMPANY OR ITS REPRESENTATIVES TO MAKE THIS FILING
ON THE PARTICIPANT’S BEHALF.

10. Miscellaneous.

(a) No Rights to Employment. The Participant acknowledges and agrees that the
vesting of the Shares pursuant to Section 2 hereof is earned only by continuing
service at the will of the Company (not through the act of being hired or
purchasing shares hereunder). The Participant further acknowledges and agrees
that the transactions contemplated hereunder and the vesting schedule set forth
herein do not constitute an express or implied promise of continued engagement
as an employee or consultant for the vesting period, for any period, or at all.

(b) Severability. The invalidity or unenforceability of any provision of this
Agreement shall not affect the validity or enforceability of any other provision
of this Agreement, and each other provision of this Agreement shall be severable
and enforceable to the extent permitted by law.

(c) Waiver. Any provision for the benefit of the Company contained in this
Agreement may be waived, either generally or in any particular instance, by the
Board of Directors of the Company.

(d) Binding Effect. This Agreement shall be binding upon and inure to the
benefit of the Company and the Participant and their respective heirs,
executors, administrators, legal representatives, successors and assigns,
subject to the restrictions on transfer set forth in Sections 4 and 5 of this
Agreement.

(e) Notice. All notices required or permitted hereunder shall be in writing and
deemed effectively given upon personal delivery or five days after deposit in
the United States Post Office, by registered or certified mail, postage prepaid,
addressed to the other party hereto at the address shown beneath his or its
respective signature to this Agreement, or at such other address or addresses as
either party shall designate to the other in accordance with this Section 10(e).

(f) Pronouns. Whenever the context may require, any pronouns used in this
Agreement shall include the corresponding masculine, feminine or neuter forms,
and the singular form of nouns and pronouns shall include the plural, and vice
versa.

 

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(g) Entire Agreement. This Agreement and the Plan constitute the entire
agreement between the parties, and supersedes all prior agreements and
understandings, relating to the subject matter of this Agreement.

(h) Amendment. This Agreement may be amended or modified only by a written
instrument executed by both the Company and the Participant.

(i) Governing Law. This Agreement shall be construed, interpreted and enforced
in accordance with the internal laws of the State of Delaware without regard to
any applicable conflicts of laws.

(j) Participant’s Acknowledgments. The Participant acknowledges that he or she:
(i) has read this Agreement; (ii) has been represented in the preparation,
negotiation, and execution of this Agreement by legal counsel of the
Participant’s own choice or has voluntarily declined to seek such counsel;
(iii) understands the terms and consequences of this Agreement; (iv) is fully
aware of the legal and binding effect of this Agreement; and (v) understands
that the law firm of Hale and Dorr LLP, is acting as counsel to the Company in
connection with the transactions contemplated by the Agreement, and is not
acting as counsel for the Participant.

11. Delivery of Certificates. The Participant authorizes the Company, on his or
her behalf, to hold the stock certificates representing the Shares until the
latest of:

 

  (i) the date on which the Shares are no longer subject to the Purchase Option;

 

  (ii) the closing of an initial underwritten public offering of the Company’s
securities pursuant to an effective registration statement filed by the Company
under the Securities Act;

 

  (iii) a sale of all or substantially all of the capital stock, assets or
business of the Company, by merger, consolidation, sale of assets or otherwise;
or

 

  (iv) the date which is no later than thirty days (30) after the date on which
the Participant ceases to be employed by the Company,

provided that, if Participant has paid the purchase price of the Shares pursuant
to a Note issued to the Company, the Company shall hold such Shares until
payment of the Note in full as pledgee under the Note and not on behalf of the
Participant pursuant to this Section 11.

12. Escrow. The Participant shall execute Joint Escrow Instructions in the form
attached hereto as Exhibit B simultaneously with the execution hereof. The Joint
Escrow Instructions shall be delivered to the person named by the Company to
serve as escrow agent thereunder. The Participant shall simultaneously deliver
to such escrow agent a stock assignment in the form attached hereto as Exhibit C
duly endorsed in blank and hereby instructs the Company to deliver to such
escrow agent, on behalf of the Participant, the certificate(s) evidencing the
Shares issued hereunder; provided that, if Participant is paying for part or all
of the Option Price for the Shares by delivering a Note to the Company then, in
accordance with the terms of the Note, the Participant shall irrevocably
instruct the Company, as pledgee under such Note, to deliver to the escrow agent
the certificate(s) evidencing the Shares issued hereunder

 

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which have been pledged as collateral for payment in full of the Note and the
related blank stock assignment(s), and the Joint Escrow Instructions shall
become effective only upon such deposit.

IN WITNESS WHEREOF, the parties hereto have executed this Agreement as of the
day and year first above written.

 

INFINITY PHARMACEUTICALS, INC. By:  

/s/ Steven H. Holtzman

Name:

 

Steven H. Holtzman

Title:

 

President and CEO

PARTICIPANT

/s/ Julian Adams

(Signature)

Julian Adams

Print Name

Address:  

280 Newbury St # 5

 

Boston, MA 02116

 

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