Synta Announces Ganetespib Program Updates

First Patient Enrolled in Phase 2 Portion of GANNET53 Study of Ganetespib in Ovarian Cancer

Phase 2 GALAXY-1 Trial of Ganetespib in NSCLC Published in Annals of Oncology

LEXINGTON, Mass.--(BUSINESS WIRE)--Jun. 2, 2015-- Synta Pharmaceuticals Corp. (NASDAQ:SNTA) today announced updates to its clinical program for Ganetespib, a next-generation inhibitor of the chaperone protein Hsp90. Ganetespib is currently being studied in several large, randomized studies, including the Phase 3 GALAXY-2 trial in non-small cell lung cancer, as well as a number of other investigator-sponsored studies in various malignancies, including acute myeloid leukemia, breast cancer and ovarian cancer.

The Company announced today that the first patient has been enrolled in the Phase 2 portion of the GANNET53 study, a randomized, pan-European study evaluating the combination of ganetespib and paclitaxel vs. paclitaxel alone in over 200 patients with metastatic, predominantly p53 mutant, platinum-resistant ovarian cancer. Enrollment in the Phase 2 portion follows the successful completion of Phase 1, the results of which were recently presented at the 2015 American Society of Clinical Oncology Annual Meeting in Chicago. The Phase 1 data demonstrated that the combination of ganetespib 150 mg/m² with paclitaxel 80 mg/m² once weekly for 3 out of 4 weeks was generally well tolerated, with no dose limiting toxicities, and was therefore chosen for the randomized phase 2 trial. GANNET53 is sponsored by Innsbruck Medical University in Austria and funded by the European Commission.

“The Phase 1 portion of GANNET53 has established the feasibility and tolerability of combining ganetespib and paclitaxel, and we eagerly look forward to the enrollment of, and results from the randomized Phase 2 portion of this trial.” said Professor Nicole Concin of the Innsbruck Medical University in Austria and the GANNET53 trial Principal Investigator. “We are very excited about a recent scientific insight into the relationship of p53 gain-of-function mutations which are the molecular hallmark of aggressive, high-grade serous ovarian carcinoma, and Hsp90 inhibition leading to tumor cell death in vitro and significant tumor control and prolonged survival in a novel p53 mutant mouse model. This unique mechanism of action and encouraging preclinical data support our choice of the ganetespib combination in an effort to optimize treatment for women with platinum-resistant ovarian cancer.”

The Company also announced today that results from the Phase 2 GALAXY-1 trial, a global, randomized, multi-center study designed to identify the patients with advanced non-small cell lung cancer (NSCLC) most likely to benefit from second-line treatment with ganetespib in combination with docetaxel versus docetaxel alone, have been published in the journal Annals of Oncology. As previously announced, a pre-specified stratification factor analysis demonstrated that patients diagnosed with advanced non-small cell lung adenocarcinoma more than six months prior to study entry derived the most benefit from combination treatment, leading to the selection of this population for the ongoing Phase 3 GALAXY-2 trial. Based on current projections and statistical assumptions, the first interim overall survival (OS) analysis of GALAXY-2 is on track to occur in the second half of 2015, and the second interim and final OS analyses will be conducted in 2016. The GALAXY-1 publication is available online here.

“We are pleased to see the GALAXY-1 findings published in the Annals of Oncology and look forward to understanding how outcomes from this trial translate to the ongoing, pivotal Phase 3 GALAXY-2 trial,” said Dr. Suresh Ramalingam, M.D., Professor, Hematology & Medical Oncology, and Director, Division of Medical Oncology, of the Winship Cancer Institute of Emory University, and a principal investigator of the GALAXY program. “Ganetespib’s unique mechanism of action has the potential to play an important role in the evolving treatment landscape in lung cancer. I look forward to the outcome of GALAXY-2.”

“We remain highly encouraged by the progress of the ganetespib program across a broad spectrum of malignancies and grateful to our collaborating investigators for their strong, ongoing support for what is today the most advanced, next generation inhibitor of Hsp90,” said Chen Schor, President and Chief Executive Officer of Synta. “We look forward to several transformative milestones on the horizon, both for ganetespib and our lead HDC candidate, STA-12-8666.”

About Ganetespib

Ganetespib, an investigational drug candidate, is a selective inhibitor of heat shock protein 90 (Hsp90), a molecular chaperone which controls the folding and activation of a number of client proteins that drive tumor development and progression. Many solid and hematologic tumors are dependent on Hsp90 client proteins including proteins involved in “oncogene addiction” (ALK, HER2, mutant BRAF and EGFR, androgen receptor, estrogen receptor, and JAK2); proteins involved in resistance to chemotherapy and radiation therapy (ATR, BCL2, BRCA1/2, CDK1/4, CHK1, survivin, and WEE1); proteins involved in angiogenesis (HIF-1alpha, VEGFR, PDGFR, and VEGF); and proteins involved in metastasis (MET, RAF, AKT, MMPs, HIF-1alpha, and IGF-1R). In preclinical models, inhibition of Hsp90 by ganetespib results in the inactivation, destabilization, and eventual degradation of these cancer-promoting proteins. Ganetespib is being evaluated in trials in lung cancer, breast cancer, and other tumor types. 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 these trials can be found at www.clinicaltrials.gov. Ganetespib has received Fast Track designation from FDA for second-line treatment of non-small cell lung adenocarcinoma in combination with docetaxel.

About Synta Pharmaceuticals

Synta Pharmaceuticals Corp. is an innovative, agile biopharmaceutical company focused on research, development and commercialization of novel oncology medicines that have the potential to change the lives of cancer patients. Synta’s lead oncology drug candidate, ganetespib, a novel heat shock protein 90 (Hsp90) inhibitor, is currently being evaluated in several clinical trials including the pivotal GALAXY-2 Phase 3 trial in non-small cell lung cancer. Building on its extensive expertise in the science of Hsp90, Synta also has a novel proprietary Hsp90 inhibitor Drug Conjugate (HDC) small molecule drug development program. IND enabling studies have commenced for the first clinical candidate from the HDC program, STA-12-8666, and preclinical evaluation of additional HDC candidates is ongoing. 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 relationship between p53 mutations and Hsp90 inhibition, the potential role of ganetespib in the evolving lung cancer treatment landscape, upcoming transformative milestones for ganetespib and STA-12-8666 and the anticipated timing for the interim and final analyses from the GALAXY-2 trial, reflect Synta’s 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, 2014 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.

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