Synta Pharmaceuticals Initiates Phase 1/2 Clinical Trial of STA-9090 in Hematologic Malignancies

Third trial of novel, synthetic small molecule Hsp90 inhibitor

LEXINGTON, Mass.--(BUSINESS WIRE)--Mar. 17, 2009-- Synta Pharmaceuticals Corp. (NASDAQ: SNTA), a biopharmaceutical company focused on discovering, developing, and commercializing small molecule drugs to treat severe medical conditions, today announced that the first patient has been treated in a Phase 1/2 clinical study of STA-9090, a novel heat shock protein 90 (Hsp90) inhibitor, in hematologic malignancies. This is the third clinical study to be initiated on STA-9090, a synthetic, small molecule Hsp90 inhibitor with a novel chemical structure that is unrelated to the ansamycin class of Hsp90 inhibitors, including 17-AAG.

“Hsp90 is recognized as a target with exciting potential for cancer therapy because of its critical role in maintaining the function of a number of cancer-promoting proteins,” said James Barsoum, Ph.D., Senior Vice President, Research, Synta. “We and our collaborators have been encouraged by results both from our preclinical data and our ongoing Phase 1 trials in solid tumor cancers. In preclinical models, we have seen potent activity in cancers that have become resistant to kinase inhibitors such as imatinib (Gleevec(R)), erlotinib (Tarceva(R)), and sunitinib (Sutent(R)), and, importantly, substantially improved safety and potency compared to the first-generation, ansamycin family of Hsp90 inhibitors, including activity in models resistant to 17-AAG. The collected data suggest hematologic malignancies are a particularly good choice for the clinical development of STA-9090.”

The open-label Phase 1/2 study in patients with hematologic malignancies is designed to identify the recommended dose of STA-9090 for further study in a hematologic population, based on a twice-weekly intravenous dosing schedule, and to characterize its safety and efficacy profile in this patient population.

Additional trials for STA-9090, in additional indications, are planned for later this year. Results from preclinical models, as well as results from ongoing Phase 1 trials, are expected to be presented at scientific and medical meetings before the end of the year.

About STA-9090

In addition to the study announced today in hematologic malignancies, Synta is currently conducting two Phase 1 clinical studies of STA-9090 both in solid tumors; one utilizing a weekly dose schedule and the other a twice-weekly dose schedule.

In preclinical studies, STA-9090 has shown the ability to inhibit multiple kinases with comparable potency to, and a broader activity profile than specific kinase inhibitors such as imatinib, erlotinib, and sunitinib. In addition, STA-9090 has shown potency 10 to100 times greater than the ansamycin family of Hsp90 inhibitors such as 17-AAG, as well as activity against a wider range of kinases. In in vivo models, STA-9090 has shown strong efficacy in a wide range of cancer types, including cancers resistant to Gleevec and Tarceva.

About Hsp90

Hsp90 is an emerging therapeutic target of interest for the treatment of cancer. It is responsible for the maturation and function of numerous signaling proteins – known as ‘client proteins’ – that are associated with cancer cell survival and proliferation. Many cancers result from specific mutations in, or aberrant expression of, these client proteins. Examples of cancer-associated client proteins of Hsp90 include c-KIT in gastrointestinal stromal tumors, epidermal growth factor receptor (EGFR) in lung cancer, and BCR-ABL in chronic myelogenous leukemia. In preclinical studies, inhibiting Hsp90 causes the degradation of these proteins and cancer cell death. Inhibiting Hsp90 has also proven effective in killing cancer cells that have developed resistance to targeted therapies such as kinase inhibitors.

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, progress and plans 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, 2007 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