Synta Announces Review of Ganetespib Results in Lung Cancer Presented at IASLC 12th Annual Targeted Therapies for the Treatment of Lung Cancer Meeting

–Review of GALAXY Trial progress suggests Phase 2b stage likely to complete as planned–

–Combination trial of ganetespib and crizotinib in ALK+ lung cancer to initiate shortly–

LEXINGTON, Mass.--(BUSINESS WIRE)--Feb. 29, 2012-- Synta Pharmaceuticals Corp. (NASDAQ: SNTA) today announced that a review of ganetespib results in non-small cell lung cancer (NSCLC) was presented by Dr. Suresh Ramalingam, Associate Professor, Chief of Thoracic Oncology and Director of Medical Oncology, Emory University, at the International Association for the Study of Lung Cancer (IASLC) 12th Annual Targeted Therapies for the Treatment of Lung Cancer Meeting. Results showed that ganetespib is active in non-small cell lung cancer; has a favorable safety profile as a monotherapy or in combination with docetaxel; shows evidence of synergy with docetaxel in preclinical models; and has pronounced single-agent clinical activity in ALK+ lung cancer, which is believed to be complementary to, rather than competitive with, direct ALK kinase inhibitors such as crizotinib.

Ganetespib is a potent inhibitor of heat shock protein 90 (Hsp90) that is structurally unrelated to first-generation, ansamycin-family Hsp90 inhibitors. Ganetespib is being evaluated in over 20 clinical trials either ongoing or currently initiating, with the most advanced clinical trial being the Phase 2b/3 GALAXY trial evaluating ganetespib with docetaxel vs. docetaxel alone in patients with advanced NSCLC who have progressed on first-line therapy. A global trial evaluating single-agent ganetespib in approximately 100 patients with ALK+ NSCLC who have not been previously treated with an ALK inhibitor is in the process of initiating.

“The GALAXY trial has enrolled over 100 patients to date,” said Dr. Ramalingam, the Principal Investigator of the trial. “The safety profile has been favorable, consistent with previously reported results, suggesting that the first-stage, Phase 2b portion of the trial will complete as planned. Ganetespib is well differentiated from first-generation, 17-AAG analog compounds by its chemical structure and by the absence of dose-limiting liver toxicities reported with the 17-AAG family. Ganetespib also differs from other, synthetic, second-generation Hsp90 inhibitors by the absence of commonly occurring, dose-limiting eye toxicity reported with some of those compounds. The safety and efficacy profile of ganetespib strongly support further evaluation of this novel agent in combination therapy with a variety of other anti-cancer agents, including taxanes and certain targeted agents such as crizotinib.”

Enrollment of the 240-patient Phase 2b portion of the GALAXY is expected to complete in Q2. Interim results, including landmark PFS, response rate, and disease control rates are expected in Q2; final progression-free survival results, as well as overall survival results, are expected in the second half of 2012.

During a panel session at the meeting, it was noted that ganetespib and crizotinib activity in ALK+ NSCLC are likely to be complementary, rather than competitive, due to their distinct mechanisms of action. Crizotinib, like other ALK inhibitors, inhibits the function of ALK by binding to the ALK protein itself; ganetespib blocks the activation of ALK by targeting its dependence on the Hsp90 chaperone. Ganetespib specifically, and Hsp90 inhibition generally, have been shown to be active in numerous models of ALK+ NSCLC for which the cancer cells have mutated and become resistant to treatment with crizotinib. At the panel session, it was announced that an investigator-sponsored trial evaluating the combination of ganetespib and crizotinib in ALK+ NSCLC patients is expected to initiate shortly.

About Ganetespib

Ganetespib (formerly STA-9090) is a potent, synthetic, small-molecule inhibitor of heat shock protein 90 (Hsp90). Hsp90 is a molecular chaperone required for the proper folding and activation of many cancer-promoting proteins, and is recognized as a key facilitator of cancer cell growth and survival. In preclinical experiments, ganetespib has shown activity in multiple tumor models both as a single agent and in combination with certain widely used cancer agents. Ganetespib is currently being evaluated in a broad range of cancer clinical trials. In these trials, ganetespib has shown clinical activity in heavily pretreated patients and has been well tolerated to date with no evidence of severe liver or common ocular toxicities seen with other Hsp90 inhibitors. The most common adverse event seen to date has been transient, mild or moderate diarrhea, which has been manageable with standard supportive care. Information on clinical trials with ganetespib can be found at www.clinicaltrials.gov.

About the Phase 2b/3 GALAXY TrialTM in NSCLC

The Phase 2b/3 trial is evaluating treatment with ganetespib and docetaxel vs. docetaxel alone, with 1:1 randomization, in patients with Stage IIIB or IV NSCLC who have completed one prior systemic therapy for advanced disease. The first stage, Phase 2b portion, will assess efficacy as measured by progression-free survival in approximately 240 patients, with co-primary endpoints for the ITT population and the subpopulation with KRAS mutation. Results from this stage will also be used to inform the choice of patient subpopulation, by biomarker or other disease characteristic for the second stage, Phase 3 portion. The second stage may enroll between 400 and 600 patients. Interim results from the first-stage portion of the trial are expected in Q2 2012. More information on the trial can be found at www.clinicaltrials.gov.

About Non-small Cell Lung Cancer

Lung cancer is the leading cause of cancer-related mortality in the United States, with over 226,000 new cases and 160,000 deaths estimated in 2012 according to the American Cancer Society. The five year survival rate for advanced-staged lung cancer is approximately 4%. Approximately 85% of all lung cancers are classified as non-small cell. Estimates for the global incidence of ALK+ NSCLC range from 40,000 to 70,000 new cases per year.

About Synta Pharmaceuticals

Synta Pharmaceuticals Corp. is a biopharmaceutical company focused on discovering, developing, and commercializing small molecule drugs to extend and enhance the lives of patients with severe medical conditions, including cancer and chronic inflammatory diseases. Synta has a unique chemical compound library, an integrated discovery engine, and a diverse pipeline of clinical- and preclinical-stage drug candidates with distinct mechanisms of action and novel chemical structures. All Synta drug candidates were invented by Synta scientists using our compound library and discovery capabilities. For more information, please visit www.syntapharma.com.

Safe Harbor Statement

This media release may contain forward-looking statements about Synta Pharmaceuticals Corp. Such forward-looking statements can be identified by the use of forward-looking terminology such as "will", "would", "should", "expects", "anticipates", "intends", "plans", "believes", "may", "estimates", "predicts", "projects", or similar expressions intended to identify forward-looking statements. Such statements, including statements relating to the timing, developments and progress of our clinical and preclinical programs, reflect our current views with respect to future events and are based on assumptions and subject to risks and uncertainties that could cause actual results to differ materially from those expressed or implied by such forward-looking statements, including those described in "Risk Factors" of our Form 10-K for the year ended December 31, 2011 as filed with the Securities and Exchange Commission. Synta undertakes no obligation to publicly update forward-looking statements, whether because of new information, future events or otherwise, except as required by law.

Source: Synta Pharmaceuticals Corp.

Synta Pharmaceuticals Corp.
Rob Kloppenburg, 781-541-7125