STOCK RESTRICTION AGREEMENT

Exhibit 10.29

Attached hereto is a form of stock restriction agreement by and among the Registrant and each of the below-named persons. The stock restriction agreement by and among the Registrant and each of the below-named persons is substantially identical in all material respects to such form, except with respect to the details that are set forth below.

The number of shares and the exercise or purchase price of each of the awards listed in the table below is presented after giving effect to the business combination between Discovery Partners International, Inc. (“Discovery Partners”) and Infinity Pharmaceuticals, Inc. (“IPI”) in accordance with the terms of the Agreement and Plan of Merger among Discovery Partners, Darwin Corp, a wholly owned subsidiary of Discovery Partners (“Darwin Corp.”), and IPI dated as of April 11, 2006, pursuant to which IPI merged with and into Darwin Corp. and became a wholly owned subsidiary of Discovery Partners and Discovery Partners changed its name to Infinity Pharmaceuticals, Inc. In addition, the number of shares and the exercise or purchase price of each of the awards listed in the table below is presented after giving effect to the Registrant’s 1-for-4 reverse stock split, which became effective on September 12, 2006.

(1) Subject to a right of repurchase, which right lapses, or “vests” in equal monthly installments over four years, beginning as of January 31, 2003

(3) Subject to a right of repurchase, which right lapses, or “vests” in equal monthly installments over four years, beginning as of January 31, 2004.

STOCK RESTRICTION AGREEMENT

AGREEMENT made this ____ day of ____ 200_, between Infinity Pharmaceuticals, Inc., a Delaware corporation (the “Company”), and Steven H. Holtzman (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 ________ shares (the “Shares”) of common stock, $.0001 par value per share (“Common Stock”) of the Company at a price of $____ 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 in any capacity by the Company for any reason or no reason, with or without cause, prior to __________, the Company shall have the right and option (the “Purchase Option”) to purchase from the Participant, for a sum of $____ per share (the “Option Price”), some or all of the Unvested Shares (as defined below).

“Unvested Shares” means the total number of Shares multiplied by the Applicable Percentage at the time the Purchase Option becomes exercisable by the Company. The “Applicable Percentage” shall be 100% less 2.08333% for each month of employment completed by the Participant with the Company from and after ___________, and (ii) zero on or after ___________.

(b) In the event that the Participant’s employment with the Company is terminated by reason of death or disability, the Purchase Option shall lapse to all of the Unvested Shares for which the Purchase Option would otherwise become exercisable. For this purpose, “disability” shall mean the inability of the Participant, due to a medical reason, to carry out his duties as an employee of the Company for a period of six consecutive months.

(c) For purposes of this Agreement, the Participant shall be deemed employed by the Company if he is an employee, consultant, advisor or member of the Board of Directors of the Company or of a parent or subsidiary of the Company.

- 10 -

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 therefore 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 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).

- 11 -

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. In the event the Company elects to pur