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Special Protocol Assessment Obtained From FDA For Phase 3 Trial of GVAX Prostate Cancer Vaccine
The SPA is a process that allows for official FDA evaluation of a Phase 3 clinical trial whose data will form the primary basis for an efficacy claim and provides trial sponsors with binding written agreement that the design and analysis of the study are adequate to support a license application submission if the study is performed according to the SPA. The SPA agreement may only be changed by the sponsor company or the FDA through a written agreement, or if the FDA becomes aware of a substantial scientific issue essential to product efficacy or safety.
"We are very pleased to be able to report the agreement we have reached with FDA in our Phase 3 development program," stated Joseph J. Vallner, Ph.D., president and chief operating officer of Cell Genesys. "We look forward to initiating the first Phase 3 clinical trial of GVAX(R) prostate cancer vaccine and are continuing to make good progress toward achieving our goal of beginning this trial by the end of the second quarter. We hope that this product may one day benefit patients with prostate cancer."
"The SPA provides Cell Genesys with a clear pathway toward regulatory submission for our lead product candidate, GVAX(R) prostate cancer vaccine, and we are pleased to have obtained this agreement with the FDA," stated Carol G. Grundfest, vice president, regulatory affairs and project management at Cell Genesys. "FDA worked very closely with us during the entire SPA process, and the dialogue we have had with the agency has been highly productive."
Cell Genesys plans to conduct two Phase 3 clinical trials of GVAX(R) prostate cancer vaccine in hormone-refractory prostate cancer patients with radiologic evidence of metastatic disease. The first trial (VITAL-1 or Vaccine ImmunoTherapy with Allogeneic prostate cancer cell Lines) will enroll chemotherapy naove, asymptomatic patients without cancer-related pain and will compare GVAX(R) vaccine to taxane chemotherapy with respect to survival benefit. The second trial (VITAL-2), which is expected to begin in the late 2004/early 2005 timeframe, will enroll symptomatic patients and will compare GVAX(R) vaccine plus taxane chemotherapy to taxane chemotherapy alone with respect to palliation of bone pain. Both trials will enroll patients with all levels of Gleason scores (a measure of the aggressiveness of prostate cancer) including the highest risk patients.
Preliminary data from an ongoing Phase 2 trial of GVAX(R) prostate cancer vaccine were reported at the June 2003 American Society of Clinical Oncology (ASCO) meeting. The fully enrolled study includes 80 patients with advanced hormone-refractory prostate cancer with evidence of metastasis (spreading) to bone and other sites. Cell Genesys has recently announced that updated results from this trial will be presented at the 2004 ASCO Annual Meeting in June. In addition, in September 2002, the company reported final data from its first Phase 2 multicenter clinical trial of GVAX(R) prostate cancer vaccine in patients with hormone-refractory metastatic prostate cancer including patients with high risk Gleason scores. Thirty-four patients with radiologic evidence of metastases were entered in the trial and received vaccine treatment as their only cancer therapy for up to a six-month period. The combined median survival for both dose groups was 26.2 months. These results compare favorably to the reported median survival for hormone- refractory prostate cancer patients with radiologically documented metastases who are treated with taxane chemotherapy, the most widely used treatment for this patient group, although such a comparison needs to be confirmed in a larger randomized controlled Phase 3 trial such as the trial the company is planning to conduct. The company plans to manufacture GVAX(R) prostate cancer vaccine for Phase 3 trials and potential market launch in its bioreactor manufacturing facility in Hayward, California.
Clinical trials of GVAX(R) cancer vaccines are underway for multiple types of cancer, including prostate cancer, lung cancer, pancreatic cancer, leukemia and myeloma. Cell Genesys' GVAX(R) cancer vaccines are whole-cell vaccines that are designed to stimulate an immune response against the patient's tumor. The vaccines are comprised of tumor cells that have been genetically modified to secrete GM-CSF, an immune stimulatory hormone that plays a key role in stimulating the body's immune response to vaccines. More than 600 patients have been treated in clinical trials with GVAX(R) cancer vaccines to date, and vaccine treatment has been shown to be well tolerated.
Source: Cell Genesys, Inc.