Positive results from Phase 2 clinical trial for STA-9090 in Stage IIIB and Stage IV patients with NSCLC

May 25 2010

Synta Pharmaceuticals Corp. (NASDAQ: SNTA) today announced that clinical activity seen in the first stage of its trial for STA-9090 in Stage IIIB and Stage IV patients with non-small cell lung cancer (NSCLC), support advancing to the second stage of the trial. This result was achieved in the first pre-defined patient cohort to complete enrollment. STA-9090 is a potent small molecule Hsp90 inhibitor with a novel chemical structure that has shown strong activity in a broad range of solid tumor and hematologic cancer models including lung, prostate, colon, breast, gastric, pancreatic, melanoma, AML, and CML.

“It is particularly encouraging that the pre-specified efficacy criteria have been achieved so early with this patient population”

"It is particularly encouraging that the pre-specified efficacy criteria have been achieved so early with this patient population," said Vojo Vukovic, M.D., Ph.D., Senior Vice President and Chief Medical Officer, Synta Pharmaceuticals. "The level of tumor shrinkage and disease control seen following treatment with STA-9090 as a single agent, as well as the favorable safety profile, suggest promising potential for STA-9090 in NSCLC. We are excited to advance to the second stage of this trial, and expect to discuss additional details and results later this year."

STA-9090 is currently being evaluated in eight ongoing clinical trials, including Phase 2 trials in NSCLC, gastrointestinal stromal tumors, colon cancer, gastric cancer, and AML. Synta expects a total of up to 15 trials for STA-9090 by the end of 2010 and is targeting initiating one or more Phase 3 registration trials for STA-9090 in 2011.

Preliminary results from the Phase 1 solid tumor trials for STA-9090 will be presented at the 2010 American Society for Clinical Oncology (ASCO) Annual Meeting June 4-8.

Scientific Background for STA-9090 in NSCLC

Emerging evidence supports the view of non-small cell lung cancer as a group of malignant diseases driven by distinct genetic abnormalities. Hsp90 is recognized as a potential therapeutic target in NSCLC due to its role in regulating numerous oncogenes that are believed to play an important role in the cause and development of NSCLC.

Earlier this year, results were presented by Synta collaborators at the Dana-Farber Cancer Institute showing that STA-9090 potently inhibited cell proliferation in 24 out of 24 human NSCLC lines tested, irrespective of EGFR, HER2 or KRAS mutational status, including models highly resistant to treatment, such as the EGFR T790M mutation. Analysis of protein expression showed that STA-9090 causes substantial down-regulation of client proteins relevant to lung cancer growth and proliferation including AKT, EGFR, MET, HER2, CDK4, and RAF1.⁽¹⁾

Also presented recently were results showing that STA-9090 enhanced the activity of agents commonly used to treat advanced lung cancer, including the taxanes paclitaxel and docetaxel; erlotinib (Tarceva®); and bevacizumab (Avastin®).⁽²⁾

Study Design in NSCLC

The open-label, multi-center Phase 2 study is designed to evaluate the efficacy and safety of STA-9090 in patients with stage IIIB or IV non-small cell lung cancer who have received prior treatment with either an approved tyrosine kinase inhibitor or chemotherapy. The trial is enrolling up to approximately 70 patients in a two-stage design. Patients are stratified into three cohorts based on certain genetic characteristics of their cancer. STA-9090 is administered as an intravenous infusion once per week for three consecutive weeks, followed by a one week rest period (four week cycle); patients continue on treatment until disease progression. The primary objective of the trial is to assess efficacy based on progression-free survival; additional objectives include assessing tumor response rates, overall survival, safety, and the impact of treatment with STA-9090 on certain biomarkers.