IPI-504 (retaspimycin hydrochloride) is a novel anti-chaperone agent that potently and selectively inhibits heat shock protein 90 (Hsp90) inhibitor. IPI-504 has shown activity as a single agent in its lead indication, refractory gastrointestinal stromal tumors (GIST), and has been generally well tolerated with an acceptable side-effect profile. Additionally, in non-small cell lung cancer (NSCLC), Infinity has reported preliminary evidence of biological activity in a heavily pretreated population of patients.

Based on the activity and safety of Infinity’s Phase 1 study of IPI-504 in patients with refractory GIST as reported at the 2008 ASCO Annual Meeting, Infinity plans to initiate an international Phase 3 registration trial of IPI-504 in refractory GIST under a Special Protocol Assessment agreement and pursuant to scientific advice from the European Medicines Evaluation Agency. Data from clinical trials with IPI-504 are available in the publication archive. Details on the anticipated Phase 3 trial of IPI-504 in patients with refractory GIST are available at www.clinicaltrials.gov.

Infinity has a broad clinical development program underway for IPI-504 targeting several major cancers for which there is a high unmet need.
IPI-504 also holds promise in combination as a complement to existing therapies for the treatment of a broad range of tumor types. In addition to the planned Phase 3 registration study of IPI-504 in patients with refractory GIST, IPI-504 is being studied in the Phase 2 portion of a Phase 1/2 trial in patients with NSCLC and a Phase 1 trial in combination with docetaxel.

Infinity is also developing an oral inhibitor of Hsp90, IPI-493, which is in a Phase 1 clinical trial in patients with advanced solid tumors.

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

IPI-504 and IPI-493 are being jointly developed by Infinity and AstraZeneca/MedImmune.