October 29, 2008

Infinity Announces Expansion of Phase 2 Clinical Study Evaluating IPI-504 in Advanced Non-Small Cell Lung Cancer

CAMBRIDGE, Mass., Oct. 29, 2008 (GLOBE NEWSWIRE) -- Infinity Pharmaceuticals, Inc. (Nasdaq:INFI) today announced that it has met pre-specified criteria to expand both arms of its ongoing Phase 2 clinical trial evaluating IPI-504 (retaspimycin hydrochloride), its lead heat shock protein 90 (Hsp90) inhibitor, in patients with advanced non-small cell lung cancer (NSCLC).

The study is designed to evaluate IPI-504 as a monotherapy in patients with Stage IIIb/IV NSCLC whose tumors have relapsed or become refractory to prior treatment with a tyrosine kinase inhibitor. Initially, the study enrolled a total of 20 patients in two equal groups: one group with known epidermal growth factor receptor (EGFR) mutations and one group with wild-type EGFR. At least one patient in each arm met the criteria to trigger the expansion phase of the study by achieving extended stable disease during treatment with IPI-504. The study will now enroll an additional 19 patients in each arm for a total of 58 patients. Infinity anticipates publishing the Phase 2 results at an appropriate medical conference in mid-2009.

"Improving outcomes for patients with non-small cell lung cancer will require medicines with new mechanisms of action. Entering the expansion phase of this trial is an important step forward for IPI-504," said Lecia Sequist, M.D., M.P.H., of the hematology-oncology division at Massachusetts General Hospital and lead investigator for the study. "The expansion of both arms of the trial could help us determine better treatment options for patients with multiple underlying genetic mutations."

"We are encouraged by the positive activity seen to date in patients with advanced non-small cell lung cancer," noted Scott Gettinger, M.D., Assistant Professor of Medicine at the Yale School of Medicine. "The ongoing expansion phase of this study will enable us to learn as much as possible about the potential of IPI-504 in this setting."

This Phase 2 study is currently enrolling patients at eight sites, with additional sites expected to open shortly. Additional information regarding the trial is available at www.clinicaltrials.gov.

IPI-504 is also being evaluated in the RING (Retaspimycin hydrochloride IN GIST) trial, an international Phase 3 registration study of IPI-504 in patients with refractory gastrointestinal stromal tumors, and in a Phase 1b trial in combination with docetaxel in patients with solid tumors. Additional clinical studies of IPI-504 are anticipated to begin by early 2009.

Furthermore, Infinity recently announced the initiation of a Phase 1 clinical study of IPI-493, its oral Hsp90 inhibitor, in patients with advanced solid tumors.

Targeting Heat Shock Protein 90 (Hsp90) and the Chaperone System

Hsp90 is a central component of the cellular chaperone system - a system that supports and stabilizes a number of cancer-causing proteins such as c-Kit, EGFR, and HER2, enabling multiple forms of cancer to thrive. Inhibition of the Hsp90 chaperone knocks out this critical source of support for cancer cells, leading to tumor growth inhibition and cancer cell death. Anti-chaperone therapy via inhibition of Hsp90 may represent a significant yet currently unaddressed strategy for treating patients with cancer. Infinity is developing two proprietary anti-chaperone agents in collaboration with AstraZeneca, IPI-504 (i.v.) and IPI-493 (oral), which have shown potent and selective inhibition of Hsp90 in preclinical studies.

About Infinity Pharmaceuticals, Inc.

Infinity is an innovative cancer drug discovery and development company seeking to discover, develop, and deliver to patients best-in-class medicines for the treatment of cancer and related conditions. Infinity combines proven scientific expertise with a passion for developing novel small molecule drugs that target emerging cancer pathways. Infinity's two most advanced programs in Hsp90 inhibition and Hedgehog signaling pathway inhibition are evidence of its innovative approach to oncology drug discovery and development. For more information on Infinity, please refer to the company's website at http://www.infi.com.

Forward Looking Statements

This press release contains forward-looking statements within the meaning of The Private Securities Litigation Reform Act of 1995. These statements involve risks and uncertainties that could cause actual results to be materially different from historical results or from any future results expressed or implied by such forward-looking statements. Such forward-looking statements include statements regarding the potential utility of IPI-504, IPI-493, and other drugs targeting the Hsp90 chaperone to treat cancer; the timetable for publication of data from the NSCLC trial; the opening of additional clinical trial sites; and future clinical trial activity for IPI-504. Such statements are subject to numerous factors, risks, and uncertainties that may cause actual events or results to differ materially from the company's current expectations. For example, there can be no guarantee that any product candidate Infinity is developing will successfully complete necessary preclinical and clinical development phases. In particular, management's expectations could be affected by risks and uncertainties relating to: results of clinical trials and preclinical studies, including subsequent analysis of existing data and new data received from ongoing and future studies; the content and timing of decisions made by the U.S. Food and Drug Administration and other regulatory authorities, investigational review boards at clinical trial sites, and publication review bodies; Infinity's ability to enroll patients in its clinical trials; Infinity's dependence on its collaboration with AstraZeneca; the results and timing of clinical trials conducted by third parties on other Hsp90 inhibitors; Infinity's ability to obtain additional funding required to conduct its research, development, and commercialization activities; unplanned cash requirements and expenditures; and Infinity's ability to obtain, maintain, and enforce patent and other intellectual property protection for any product candidates it is developing. These and other risks that may impact management's expectations are described in greater detail under the caption "Risk Factors" included in Infinity's quarterly report on Form 10-Q for the quarter ended June 30, 2008, as filed with the Securities and Exchange Commission on August 6, 2008. Further, any forward-looking statements contained in this press release speak only as of the date hereof, and Infinity expressly disclaims any obligation to update any forward-looking statements, whether as a result of new information, future events, or otherwise.

This news release was distributed by GlobeNewswire, www.globenewswire.com

 CONTACT: Infinity Pharmaceuticals, Inc.          Monique Allaire          617-453-1105          [email protected]          http://www.infi.com