Cell Genesys Announces Encouraging Results from Phase 1/2 Trial of GVAX Immunotherapy for Prostate Cancer in Recurrent Disease
Friday April 11, 8:30 am ET
SOUTH SAN FRANCISCO, Calif.--(BUSINESS WIRE)--Cell Genesys, Inc. (Nasdaq:CEGE - News) today announced data from a completed Phase 1/2 clinical trial (G-9802) of GVAX immunotherapy for prostate cancer in men with recurrent prostate cancer who had not yet received treatment with hormone replacement therapy following relapse after prostate cancer surgery and/or radiation therapy. Data from the trial, which enrolled 19 patients, indicate that GVAX immunotherapy for prostate cancer results in a statistically significant increase in median PSA (prostate-specific antigen) doubling time as well as the formation of prostate cancer-associated antibodies in 79 percent of patients who received GVAX immunotherapy. These data will be presented today by Kristen Hege, M.D., vice president of Clinical Research and Development at Cell Genesys, at the annual meeting of the Tumor Vaccine and Cell Therapy Working Group being held in San Diego, California, in conjunction with the American Association for Cancer Research (AACR) annual meeting.
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Data from the trial indicate a favorable increase in PSA doubling time from 28.7 weeks before receiving GVAX immunotherapy to 57.1 weeks after receiving the product (p=0.0095). In addition, 16 patients (84 percent) experienced a decline in PSA slope, a potential measure of the rate of disease progression, after receiving GVAX immunotherapy (p=0.018). PSA levels in eight of 19 patients (42 percent) remained stable during the six-month treatment period, with a median time to PSA progression of 9.7 months. Additionally, analysis of patient sera taken before and after receiving GVAX immunotherapy showed that 15 of the 19 patients (79 percent) developed new or enhanced antibody responses against either PC-3 or LNCaP, the two prostate cancer cell lines that comprise GVAX immunotherapy for prostate cancer. The product was generally well tolerated, with the most common side effects being injection site reactions in most patients and mild flu-like symptoms in some patients. No dose-limiting toxicities were observed.
“These data suggest that GVAX immunotherapy for prostate cancer may have clinical activity for men with early stage, recurrent prostate cancer,” stated Robert J. Dow, MBChB, senior vice president of Medical Affairs and chief medical officer of Cell Genesys. “We are now planning a larger randomized trial to further examine the potential application of GVAX immunotherapy in this patient population and also look forward to learning more from a study currently under way that is evaluating the product in combination with docetaxel as a preoperative therapy in men with high-risk prostate cancer.”
The multicenter, open-label, Phase 1/2 clinical trial reported on today was designed to evaluate the safety and activity of GVAX immunotherapy for prostate cancer in men with early stage, recurrent prostate cancer. All of the 19 enrolled had non-castrate (hormone-sensitive) prostate cancer with PSA recurrence following prostatectomy and/or radiation therapy, and no radiologic evidence of metastases. Patients were administered an initial dose of GVAX immunotherapy for prostate cancer followed by bi-weekly injections for a six-month period. Patients were monitored for an additional six months following the last injection for adverse events, PSA response, changes in PSA kinetics, and the induction of prostate cancer-associated antibodies. Long term safety monitoring was conducted and at a median follow up of six years, 17 of the 19 patients remained alive.
The results reported today build upon the previously reported findings in an initial study (G-9705) of GVAX immunotherapy for prostate cancer in patients with early stage, non-castrate disease. These results, which were published in the July 2006 issue of Clinical Cancer Research showed that 16 (76 percent) of the 21 patients enrolled in the trial had a statistically significant decline in PSA slope after receiving GVAX immunotherapy for prostate cancer compared to the five patients who did not (p<0.001). Prostate cancer-associated antibodies were also induced in these patients. The patients in this initial study received GVAX immunotherapy for only an eight-week period. The patients in the G-9802 study received GVAX immunotherapy for up to six months, which is the same period of time being employed in the ongoing Phase 3 trials of GVAX immunotherapy for prostate cancer.
About GVAX Immunotherapy for Prostate Cancer
GVAX immunotherapy for prostate cancer is a whole-cell, non patient-specific product designed to present the immune system with a broad spectrum of tumor antigens and stimulate an immune response against the patient's tumor. GVAX immunotherapy for prostate cancer is comprised of two prostate tumor cell lines that have been modified to secrete GM-CSF (granulocyte-macrophage colony-stimulating factor), an immune stimulatory protein that plays a key role in stimulating the body's immune response, and then irradiated for safety. Cell Genesys, in partnership with Takeda Pharmaceutical Company Limited, is currently evaluating GVAX immunotherapy for prostate cancer in two Phase 3 clinical trials, VITAL-1 and VITAL-2, for the treatment of advanced stage, hormone-refractory prostate cancer. In 2007, the VITAL-1 trial completed enrollment with 626 patients and in January 2008, Cell Genesys announced that the Independent Data Monitoring Committee (IDMC) had completed a pre-planned interim analysis for VITAL-1 and recommended that the study continue. The company currently estimates that there will be sufficient events to trigger the final analysis for VITAL-1 in the second half of 2009. Patients are continuing to be enrolled in the VITAL-2 trial at approximately 100 clinical trial sites located in North America and Europe. Cell Genesys is targeting the completion of enrollment for VITAL-2 with approximately 600 patients in the first half of 2009 and expects that there will be sufficient events to trigger the pre-planned interim analysis in the same time frame. GVAX immunotherapy for prostate cancer is currently being manufactured in Cell Genesys’ bioreactor manufacturing facility, a facility that is capable of producing the product during commercialization.
About Cell Genesys
Cell Genesys is focused on the development and commercialization of novel biological therapies for patients with cancer. The company is currently pursuing two clinical stage product platforms – GVAX® cancer immunotherapies and oncolytic virus therapies. Ongoing clinical trials include Phase 3 trials of GVAX immunotherapy for prostate cancer, which is being developed in partnership with Takeda Pharmaceutical Company Limited, Phase 2 trials of GVAX immunotherapies for pancreatic cancer and for leukemia, and a Phase 1 trial of CG0070 oncolytic virus therapy for bladder cancer. Cell Genesys continues to hold an equity interest in its former subsidiary, Ceregene, Inc., which is developing gene therapies for neurodegenerative disorders. Cell Genesys is headquartered in South San Francisco, CA and has its principal manufacturing operation in Hayward, CA. For additional information, please visit the company’s website at www.cellgenesys.com.
Forward-Looking Statement
Statements made herein about the company, other than statements of historical fact, including statements about the progress, results, findings and timing of the company's clinical trials and preclinical programs and the nature of product pipelines are forward-looking statements and are subject to a number of uncertainties that could cause actual results to differ materially from the statements made, including risks associated with the success of clinical trials and research and development programs, the regulatory approval process for clinical trials, competitive technologies and products, patents, continuation of corporate partnerships and the need for additional financings. For information about these and other risks which may affect Cell Genesys, please see the company's reports on Form 10-Q, 10-K, and 8-K and other reports filed from time to time with the Securities and Exchange Commission. The company assumes no obligation to update the forward-looking information in this press release.
Contact:
Cell Genesys, Inc.
Susan Ferris, 650-266-3200
Investor Relations
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Source: Cell Genesys, Inc.
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