2 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 utility of Hsp90 and Hedgehog pathway inhibition to treat cancer; the ability of IPI-504 to be the first-to-market Hsp90 inhibitor; future clinical trial activity for IPI-504; the presentation of clinical data for IPI-504; the achievement of annual clinical objectives; estimates of 2008 financial performance; and the expectation that Infinity will have cash to support its current operating plan into 2010. • 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, or that any preclinical data will be replicated in clinical trials. 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. FDA 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; 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 which 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. | 
