Infinity Pharmaceuticals, Inc. (NASDAQ: INFI) today announced the closing of an underwritten public offering of its common stock, at a price of $40.00 per share, by existing shareholders Beacon Company and Rosebay Medical Company L.P., including shares that were transferred to Beacon and Rosebay by Purdue Pharma L.P., an associated company of Beacon and Rosebay. The total number of shares of common stock sold was 11,416,565, composed of 10,000,000 shares of common stock initially sold and an additional 1,416,565 shares of common stock sold pursuant to the exercise of the underwriters' over-allotment option. 5,708,282 shares of common stock were sold by Beacon and 5,708,283 shares of common stock were sold by Rosebay. Immediately following the closing, Beacon, Rosebay and Purdue will not hold any shares of Infinity. Infinity did not sell any shares or receive any proceeds from the offering, and the total number of shares of its outstanding common stock has not changed as a result of the offering.

The joint book-running managers for the offering were Morgan Stanley & Co. LLC and J.P. Morgan Securities LLC.

The securities described above were offered pursuant to an effective shelf registration statement that was previously filed with the Securities and Exchange Commission (SEC). The final prospectus supplement and accompanying prospectus related to this offering may be obtained free of charge by visiting the Securities and Exchange Commission's website at www.sec.gov, or by contacting:

Morgan Stanley & Co. LLC     J.P. Morgan Securities LLC
Attn: Prospectus Department c/o Broadridge Financial Solutions
180 Varick Street, 2nd Floor 1155 Long Island Avenue
New York, NY 10014 Edgewood, NY 11717
Phone: 866-718-1649 Phone: 866-803-9204

Email: prospectus@morganstanley.com

This press release does not constitute an offer to sell or a solicitation of an offer to buy the securities in this offering, nor shall there be any sale of these securities, in any state or other jurisdiction in which such offer, solicitation or sale would be unlawful prior to the registration or qualification under the securities laws of any such state or other jurisdiction.

About Infinity Pharmaceuticals, Inc.

Infinity is an innovative drug discovery and development company seeking to discover, develop and deliver to patients best-in-class medicines for diseases with significant unmet need. Infinity combines proven scientific expertise with a passion for developing novel small molecule drugs that target emerging disease pathways. Infinity's programs focused on the inhibition of phosphoinositide-3-kinase and heat shock protein 90 are evidence of its innovative approach to drug discovery and development.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of The Private Securities Litigation Reform Act of 1995 that are based on current expectations, forecasts and assumptions that involve risks and uncertainties. Forward-looking statements include statements regarding Infinity's expectations, beliefs, intentions or strategies regarding the future, and can be identified by forward-looking words such as "anticipate," "believe," "could," "continue," "estimate," "expect," "intend," "may," "should," "will," and "would" or similar words. Important factors could cause actual results to differ materially from these forward-looking statements, including market conditions as well as risks and uncertainties associated with Infinity's business, including those risks and uncertainties described in "Risk Factors" in the final prospectus supplement, and in "Risk Factors" and elsewhere in Infinity's annual report on Form 10-K for the year ended December 31, 2012, each of which has been filed with the SEC, as well as in other filings that Infinity periodically makes with the SEC. Any forward-looking statements contained in this press release speak only as of the date hereof, and Infinity anticipates that subsequent events and developments will cause its views to change. While Infinity may elect to update these forward-looking statements at some point in the future, Infinity expressly disclaims any obligation to update any forward-looking statements, whether as a result of new information, future events or otherwise.

Infinity Pharmaceuticals, Inc.
Jaren Irene Madden, 617-453-1336
Jaren.Madden@infi.com
http://www.infi.com