Infinity Pharmaceuticals, Inc. (IPI) has developed a pipeline of product candidates for multiple cancer indications. The Company’s lead product candidate, retaspimycin hydrochloride (IPI-504) is an intravenously-administered small molecule inhibitor of heat shock protein 90 (Hsp90). Hsp90 is a central component of the cellular chaperone system, which supports and stabilizes 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. In October 2008, the commenced an international Phase III registration study of IPI-504 in patients with refractory gastrointestinal stromal tumors (GIST), based on the activity and safety data from a Phase I trial reported during the year ended December 31, 2008.