Hsp90 and IPI-504

IPI-504 is Infinity’s proprietary small molecule therapeutic drug candidate that, in preclinical studies, potently and selectively inhibited Hsp90, thereby killing cancer cells. Hsp90 is an emerging therapeutic target of interest for the treatment of cancer. Proteins are the mainstay of structural and signaling elements of all cells. Hsp90 functions to stabilize and maintain the activity of proteins in the cancer cell, thereby allowing a cancer cell to survive despite an abundance of misfolded and unstable proteins. Inhibition of Hsp90 has broad therapeutic potential for the treatment of patients with solid tumors and blood-related cancers, including cancers that are resistant to other drugs.

IPI-504 preferentially targets and accumulates in tumor tissues, sparing healthy tissues. In preclinical studies it has demonstrated a broad potential to treat certain cancers as both a single agent as well as in combination with existing anti-cancer drugs. The water-based formulation of IPI-504 is easy to deliver as an intravenous infusion. Infinity is currently conducting two Phase 1 clinical trials with intravenous formulations of IPI-504. In July 2005, Infinity initiated the first of these Phase 1 clinical trials in refractory multiple myeloma. In December 2005, Infinity initiated the second Phase 1 clinical trials with IPI-504 in refractory gastrointestinal stromal tumors (GIST). Infinity has also begun developing an oral formulation of IPI-504, which if successful, could be a more convenient route of administration for cancer therapy.