Infinity Initiates Phase I Clinical Trial of IPI-504 for Multiple Myeloma

CAMBRIDGE, Mass. -- Infinity Pharmaceuticals, Inc. today announced the initiation of a phase I clinical trial of IPI-504, the company's Heat Shock Protein 90 (Hsp90) inhibitor and lead investigational anticancer agent. Research shows that inhibition of Hsp90 forces cancer cells to "commit suicide" through a process of programmed cell death or apoptosis. IPI-504 is initially being developed as a potential treatment for patients with multiple myeloma and will subsequently be developed for additional hematologic cancers and solid tumor indications.

This open-label safety assessment phase I trial of IPI-504 will evaluate the potential anti-tumor activity and the tolerability of various doses in subjects with relapsed or relapsed, refractory multiple myeloma. Initial subjects in the study are being treated at St. Vincent's Comprehensive Cancer Center in New York under the direction of Sundar Jagannath M.D.

"We are excited and encouraged to begin our first clinical trial of IPI- 504 and look forward to further exploring its use as a single agent and in combination with other chemotherapeutic agents to attack cancer cell survival," said Julian Adams, Ph.D., Chief Scientific Officer, Infinity. "A key advantage of the compound relative to other Hsp90 inhibitors is its intravenous administration to patients using a simple water-based formulation."

IPI-504 is an innovative and proprietary small molecule compound specifically designed to attack a cancer cell's machinery for maintaining protein homeostasis, the process by which cells continue the orderly formation and destruction of proteins. Infinity presented preclinical data on IPI-504 during the 96th Annual Meeting of the American Association for Cancer Research held in Anaheim, California in April 2005. In vitro studies demonstrate that IPI-504 binds to Hsp90 more tightly than 17-AAG. In addition, IPI-504 acting as a sole agent shows potent cytotoxic activity against multiple myeloma cells which are resistant to current therapies including bortezomib-resistant cells. When examined in vivo, IPI-504 demonstrated a 71% reduction in multiple myeloma tumor growth relative to controls in a preclinical xenograft model. It was also found to decrease serum Immunoglobulin lambda chain concentrations (similar to M protein in the human disease), enabling monitoring of disease burden with a surrogate marker. Furthermore, in vivo reduction in tumor growth was also observed in several other human xenograft models, including models of breast, prostate and ovarian cancer.