IPI-504 (retaspimycin hydrochloride) is a novel potent and selective heat shock protein 90 (Hsp90) chaperone inhibitor. Hsp90 chaperone inhibition represents a promising strategy for addressing a broad range of solid and hematologic cancers.

During the American Society of Clinical Oncology Annual Meeting held in June 2010, Infinity reported final data from a Phase 2 clinical trial of IPI-504 in patients with NSCLC, which showed an objective response rate of 7% in the overall study population of 78 patients: 10% in patients who were EGFR wild-type, 4% in those with EGFR mutations, and 12% among KRAS wild-type patients. Among the patients with oncogenic anaplastic lymphoma kinase (ALK) gene rearrangements, there was a 67% response rate, with two of three patients experiencing partial responses and the third patient experiencing a 24% disease reduction, all three of whom received IPI-504 for at least six months. IPI-504 was generally well tolerated in this study. Validation of these findings is ongoing in an investigator-sponsored trial (IST) at Massachusetts General Hospital by Dr. Lecia Sequist, the principal investigator of the Phase 2 study.

Infinity is continuing to evaluate patients in a Phase 1b clinical trial of IPI-504 in combination with Taxotere® (docetaxel) that is currently focused on patients with advanced NSCLC.

Infinity has several issued U.S. patents broadly covering, among other things, IPI-504 and other related molecules potentially useful for treating cancer. These patents include composition of matter, pharmaceutical composition, method of treatment and synthetic method claims.