Synta Pharmaceuticals Corp. a biopharmaceutical company focused on discovering, developing, and commercializing small molecule drugs to treat severe medical conditions, has achieved operational milestones triggering $15 million in payments from GlaxoSmithKline (GSK) under its collaboration agreement for the development and commercialization of elesclomol. Elesclomol is an investigational first-in-class oxidative stress inducer that triggers apoptosis (programmed cell death) in cancer cells. Elesclomol is currently being studied in combination with paclitaxel in an on-going Phase 3 clinical trial (SYMMETRYSM) in metastatic melanoma. Synta also recently initiated a Phase 1/2 clinical trial of elesclomol in combination with docetaxel in hormone refractory metastatic prostate cancer with trials in other indications planned for 2009. Elesclomol is not yet approved for any indication in any market. Under the terms of the collaborative agreement with GSK, Synta is eligible for a total of $585 million in pre-commercial milestone payments. These miletsones are related to operational progress, clinical progress, or regulatory filings and outcomes in melanoma and other cancer indications: $145 million in melanoma-related operational and regulatory milestones, including: $25 million for milestones achieved and announced previously; $10 million for milestones achieved and announced today; $10 million for additional milestones expected prior to completion of enrollment; $25 million upon meeting the primary endpoint or agreement to file for regulatory approval; and $75 million in potential milestone payments for melanoma regulatory filings and approvals. * $440 million in milestone payments for clinical and regulatory progress in other cancer indications, including; $5 million in milestones announced today. In addition to the above pre-commercial milestone payments, Synta is eligible for $300 million in sales milestones, 40-50% share of operating profits in the United States, and double-digit royalties on sales outside the United States. Synta has earned a total of $120 million in payments from GSK to date, including the $80 million up front payment in 2007 and the $40 million to date in 2008. As previously announced, Synta expects to complete enrollment in the Phase 3 SYMMETRY trial in January or February of 2009 and conduct the primary endpoint analysis for progression- free survival shortly thereafter. Collaboration with GlaxoSmithKline In October 2007, Synta and GSK entered into a collaboration agreement for elesclomol. Under the terms of the agreement, the companies will jointly develop and commercialize elesclomol in the U.S. and GSK will have exclusive responsibility for development and commercialization of elesclomol outside the U.S. Synta and GSK are working closely together to further the clinical development of elesclomol as well as prepare for the manufacture and commercial launch of elesclomol.