Synta Announces Results Show Ganetespib Sensitizes Rectal Cancer Cells to Chemoradiotherapy

Phase 1/2 clinical trial of ganetespib with radiation and chemotherapy to initiate by Q1 2012

LEXINGTON, Mass., Nov 10, 2011 (BUSINESS WIRE) -- Synta Pharmaceuticals Corp. (NASDAQ: SNTA) today announced results presented at the Chemotherapy Foundation Symposium showing that ganetespib can sensitize rectal cancer cells to chemoradiotherapy through inhibition of Hsp90.

Ganetespib is a potent inhibitor of heat shock protein 90 (Hsp90) that is structurally unrelated to first-generation, ansamycin-family Hsp90 inhibitors such as 17-AAG, 17-DMAG and IPI-504.

"Rectal cancer is a devastating disease with few effective treatment options. Results of randomized clinical trials involving 5FU, capecitabine, oxaliplatin and radiation have all failed to improve patient outcomes, which is why the ganetespib results presented today are particularly encouraging," said by Bassel F. El-Rayes, M.D., Winship Cancer Institute, Emory University. "These results demonstrate that ganetespib in combination with 5FU and radiation reduces rectal cancer cell colony formation more than 5 FU and radiation alone. Results of additional experiments show that Hsp90 inhibition in rectal cancer is a potential therapeutic target based on the inhibition of key oncoproteins that drive rectal cancer cell growth, such as PI3K, NF-kB, and p-AKT. Ganetespib also induces robust inhibition of HIF-1a and VEGF expression resulting in reduced vascular density in two rectal cancer cell lines. This antiangiogenic effect inhibits blood supply to tumors, which is believed to further contribute to tumor growth arrest and apoptosis. These results, together with the encouraging clinical activity and safety seen with ganetespib in trials involving over 400 patients treated to date, have led to our plans for a Phase 1/2 clinical trial of ganetespib in combination with capecitabine and radiotherapy in rectal cancer. We expect this trial to initiate in early 2012."

"Ganetespib has already shown clear signs of activity as a single agent in a number of cancers, including non-small cell lung cancer, breast cancer, and gastric cancer," said Vojo Vukovic, M.D., Ph.D., SVP and Chief Medical Officer, Synta. "We believe that ganetespib can also enhance the activity of approved agents including docetaxel and bortezomib (VELCADE®); combination trials with these agents are ongoing or initiating. The results presented today suggest that ganetespib could also enhance the activity of chemoradiotherapy. This represents a very large patient population and important medical need."

About Rectal Cancer

According to the American Cancer Society, approximately 40,000 Americans will be diagnosed with rectal cancer in 2011. The 5 year survival rate for Stage IV rectal cancer is estimated to be 6%.

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 diarrhea, which has been manageable with standard supportive care. Information on clinical trials with ganetespib can be found at http://clinicaltrials.gov/ct2/results?term=ganetespib.

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 http://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, 2010 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