Safety and Overall Survival Data in Docetaxel-Refractory Patients Enrolled in the Satraplatin SPARC Trial Being Presented at 2009 ASCO Genitourinary Cancers Symposium
Improvement in overall survival seen in subset of patients refractory to docetaxel
MARTINSRIED/MUNICH, Germany & PRINCETON, N.J.--(BUSINESS WIRE)--Feb 27, 2009 - <!-- cpurl -->GPC Biotech<!-- /cpurl --> AG (Frankfurt Stock Exchange: GPC, NASDAQ: GPCB) today announced that data from the double-blind, randomized <!-- ppurl -->satraplatin<!-- /ppurl --> Phase 3 trial, the SPARC trial (Satraplatin and Prednisone Against Refractory Cancer) are being presented at the 2009 American Society for Clinical Oncology (ASCO) Genitourinary Cancers Symposium in Orlando, Florida. The SPARC trial evaluated satraplatin plus <!-- ppurl -->prednisone<!-- /ppurl --> versus placebo plus prednisone in 950 patients with androgen-independent or castrate-refractory prostate cancer (CRPC) who had progressed after initial chemotherapy. The data being presented today are the result of pre-specified exploratory analyses of the SPARC trial, and they show an improvement in overall survival in a subset of patients refractory to <!-- ppurl -->docetaxel<!-- /ppurl -->.
Of the 950 patients in the SPARC trial, 488 received first-line docetaxel. As there is no universally accepted definition of docetaxel-refractory CRPC patients, two definitions were adopted based on the literature: R1) disease progression while on docetaxel or within 100 days of the last docetaxel dose; and R2) disease progression while on docetaxel or within 50 days of the last docetaxel dose. Both R1 and R2 patients were randomized to the SPARC trial within 100 days of receiving their last docetaxel dose.
When stratified and adjusted for the three pre-specified prognostic factors which showed statistically significant imbalances between the two treatment arms (lactate dehydrogenase, hemoglobin and alkaline phosphatase), there was a positive trend toward better overall survival for the patients treated with satraplatin observed in the following three groups: 1) in those patients who had progressed after receiving docetaxel - hazard ratio 0.78 (95% CI: 0.61, 0.99); 2) in the R1 group - hazard ratio 0.65 (95% CI: 0.47, 0.90) and 3) in the R2 group - hazard ratio 0.69 (95% CI: 0.49, 0.96).
“There are currently no approved treatment options for advanced prostate cancer patients once they become refractory to docetaxel. Thus, there is an urgent need for new therapies for these patients,” said Daniel Petrylak, M.D., Associate Professor of Medicine at Columbia University College of Physicians & Surgeons, Director of the Genitourinary Oncology Program at New York-Presbyterian Hospital/Columbia, and one of the principal investigators of the SPARC trial. “I am encouraged by the positive trends in overall survival observed in patients refractory to docetaxel when adjusted for significant prognostic factors, along with the treatment's safety profile. These findings warrant additional testing in prospectively designed trials in docetaxel-refractory CRPC patient populations.”
Safety findings in the SPARC trial were consistent with previous clinical studies involving satraplatin. Myelosuppression (decrease in the production of blood cells by the bone marrow) was the most common adverse reaction associated with satraplatin therapy, with 98.9% of patients in the satraplatin arm experiencing myelosuppression of any grade. A total of 22.6% of patients in the satraplatin arm experienced grade 3 or 4 thrombocytopenia; 14.5% had grade 3 or 4 leucopenia; 22.3% had grade 3 or 4 neutropenia and 11.9% experienced grade 3 or 4 anemia. Gastrointestinal toxicities of any grade were the most frequent non-hematological adverse events (occurring in 59.5% of the patients receiving satraplatin). A total of 7.8% of patients in the satraplatin arm experienced grade 3 or 4 gastrointestinal (GI) toxicities, including nausea, vomiting, diarrhea and constipation. The incidence of grade 3 or 4 GI toxicities for the docetaxel-refractory groups was 12.5% in the R1 group and 13.3% in the R2 group. In addition, 5.1% of patients in the satraplatin arm in the SPARC trial experienced grade 3 or 4 fatigue/asthenia and 4.3% experienced grade 3 or 4 infections.
Satraplatin, an investigational drug, is a member of the platinum family of compounds. Platinum-based drugs are a critical part of modern chemotherapy treatments and are used to treat a wide variety of cancers. All platinum drugs currently on the market require intravenous administration. Satraplatin is an oral compound that clinical trial patients are able to take at home. GPC Biotech has a license agreement with Yakult Honsha Co. Ltd. under which Yakult has exclusive commercialization rights to satraplatin for Japan. GPC Biotech is currently talking with Yakult regarding further development and registrational efforts for satraplatin. GPC Biotech in-licensed satraplatin from Spectrum Pharmaceuticals, Inc.
About GPC Biotech
GPC Biotech AG is a publicly traded biopharmaceutical company focused on developing anti-cancer drugs. The Company currently has two programs in clinical development: satraplatin, an oral platinum compound and RGB-286638, a multi-targeted protein kinase inhibitor. On February 18, 2009 the Company announced plans to combine its business with <!-- cpurl -->Agennix<!-- /cpurl -->, Incorporated, a privately-held biotechnology company located in Houston, Texas. Agennix is developing oral <!-- ppurl -->talactoferrin<!-- /ppurl -->, a product candidate that is currently in Phase 3 trials for non-small cell lung cancer. GPC Biotech AG is headquartered in Martinsried/Munich (Germany) and has a wholly owned U.S. subsidiary in Princeton, New Jersey. For additional information, please visit GPC Biotech's Web site at www.gpc-biotech.com.
This press release contains forward-looking statements, which express the current beliefs and expectations of the management of GPC Biotech, including statements about the efficacy and safety of satraplatin. Such statements are based on current expectations and are subject to risks and uncertainties, many of which are beyond our control, that could cause future results, performance or achievements to differ significantly from the results, performance or achievements expressed or implied by such forward-looking statements. Actual results could differ materially depending on a number of factors, and we caution investors not to place undue reliance on the forward-looking statements contained in this press release. Satraplatin may not be approved for marketing in a timely manner, if at all. We direct you to GPC Biotech's Annual Report on Form 20-F for the fiscal year ended December 31, 2007 and other reports filed with the U.S. Securities and Exchange Commission for additional details on the important factors that may affect the future results, performance and achievements of GPC Biotech. Forward-looking statements speak only as of the date on which they are made and GPC Biotech undertakes no obligation to update these forward-looking statements, even if new information becomes available in the future.
Satraplatin has not been approved by the FDA in the U.S., the EMEA in Europe or any other regulatory authority and no conclusions can or should be drawn regarding its safety or effectiveness. Only the relevant regulatory authorities can determine whether satraplatin is safe and effective for the use(s) being investigated.
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Posted: February 2009