CAMBRIDGE, Mass., Oct. 24, 2008 (GLOBE NEWSWIRE) -- Infinity Pharmaceuticals, Inc. (Nasdaq:INFI) today announced initiation of a Phase 3 registration trial of IPI-504 (retaspimycin hydrochloride), its lead inhibitor of heat shock protein 90 (Hsp90), in patients with refractory gastrointestinal stromal tumors (GIST). Initiation of the Phase 3 trial of IPI-504 follows promising safety and activity data reported earlier this year from a Phase 1 study in patients with refractory GIST and other soft tissue sarcomas. The trial is expected to be completed within approximately two years, positioning IPI-504 as the potential first-in-class Hsp90 inhibitor.