Our GVAX immunotherapy for prostate cancer is a non patient-specific product comprised of two genetically-modified prostate cancer cell lines. We intend to develop and manufacture this immunotherapy as an “off-the-shelf” pharmaceutical for use after hormonal therapy for advanced-stage prostate cancer. Prostate cancer is the second leading cause of cancer death in men in the United States, with approximately 30,000 men dying each year from the disease. When a man is diagnosed with early-stage prostate cancer, he is treated with either a prostatectomy (surgical removal of the prostate) or radiation therapy. If the patient relapses, he is treated with hormone therapy to suppress testosterone in order to reduce the growth of the tumor. When the hormone therapy fails, the patient may or may not be treated with chemotherapy depending upon whether the disease has spread, or metastasized, to other parts of the body. We have designed our Phase 3 clinical trials to evaluate whether GVAX immunotherapy for prostate cancer can benefit patients who have ceased responding to (become refractory to) hormone therapy and have metastatic disease.

We have completed five Phase 1 and Phase 2 clinical trials of our GVAX immunotherapy for prostate cancer in approximately 200 patients with various stages of recurrent prostate cancer, and the immunotherapy has had a favorable safety profile in each trial. These clinical trials include two Phase 2 clinical trials in hormone-refractory prostate cancer patients with radiologic evidence of metastatic disease (“metastatic HRPC”), which is the target population for our current Phase 3 trials. These trials were designed to evaluate the safety and efficacy of the immunotherapy, as well as dosing regimens for Phase 3 clinical trials.

In September 2002, we reported final data from our first Phase 2 multicenter clinical trial of the prostate cancer immunotherapy in metastatic HRPC. Thirty-four patients were entered in the trial and were assigned to receive either low dose (24 patients) or high dose (10 patients) of the immunotherapy 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 previously published median survival for Taxotere® (docetaxel) chemotherapy in combination with prednisone. This Taxotere regimen is approved by the FDA for the treatment of patients with this stage of prostate cancer and is now the currently approved standard of care. Our ongoing Phase 3 program is designed to confirm this potential survival benefit for GVAX immunotherapy for prostate cancer.

Updated data from the second Phase 2 clinical trial were presented at the February 2006 American Society of Clinical Oncology (ASCO) Prostate Cancer Symposium. The fully enrolled study includes 80 HRPC patients with evidence of metastasis (spreading) to the bone and other sites. Patients enrolled in this Phase 2 clinical trial, which evaluated escalating doses of the cancer immunotherapy, were monitored for safety and for evidence of clinical activity induced by the immunotherapy. The results to date for the 22 patients who received a dose comparable to that being employed in our ongoing Phase 3 trials indicate that the median survival has not yet been reached for these 22 patients, and the estimated Kaplan-Meier median survival is expected to meet or exceed 29.1 months based on the patients still in follow-up. Four patients have withdrawn consent to further follow-up and thus were censored in the analysis.

Data from a Phase 1 clinical trial of GVAX immunotherapy for prostate cancer, administered in combination with ipilimumab (MDX-010), a fully human antibody to CTLA-4 being jointly developed by Medarex and Bristol-Myers Squibb were presented at the February 2007 ASCO Prostate Cancer Symposium. Twelve patients with advanced prostate cancer have completed dosing to date, including six patients who received the combination therapy at the therapeutic doses currently being evaluated in both GVAX and ipilimumab Phase 3 clinical trials. Antitumor activity was observed in five of these six patients, including greater than 50% reductions in prostate-specific antigen (PSA) levels that were maintained in four of these patients for at least six months with two patients having greater than 95% reductions. Moreover, clinical evidence of antitumor activity was observed in three of the five PSA responders. All five patients with PSA declines experienced immune-mediated endocrine deficiencies which were similar in type to those previously reported for ipilimumab and were successfully treated with standard hormone replacement therapy. This dose-escalation combination trial is currently expected to enroll a total of approximately 25 to 30 patients.

We are conducting two Phase 3 clinical trials of GVAX immunotherapy for prostate cancer in metastatic HRPC. The first Phase 3 clinical trial (VITAL-1) commenced in July 2004 and compares GVAX immunotherapy for prostate cancer to Taxotere chemotherapy administered with prednisone with respect to survival benefit in metastatic HRPC patients who are asymptomatic with respect to cancer-related pain. The VITAL-1 trial is designed to demonstrate superior survival in the patients receiving GVAX cancer immunotherapy compared to patients receiving Taxotere plus predinsone therapy and is expected to enroll approximately 600 patients. The second Phase 3 clinical trial, referred to as the VITAL-2 trial, commenced in June 2005 and compares GVAX immunotherapy for prostate cancer plus Taxotere chemotherapy to Taxotere chemotherapy plus prednisone with respect to survival benefit in metastatic HRPC patients with cancer-related pain. We expect to enroll approximately 600 patients in the VITAL-2 trial. VITAL-1 and VITAL-2 are both being conducted in the United States, Canada and Europe.

We received a Special Protocol Assessment, or SPA, from the FDA for VITAL-1 in May 2004 and for VITAL-2 in May 2005. Under this procedure, a sponsor may seek the FDA’s agreement on the design and analysis of a clinical trial intended to form the primary basis of an effectiveness claim. If the FDA agrees in writing, its agreement may not be changed after the trial begins except in limited circumstances, such as the FDA determining that a substantial scientific issue essential to determining the safety or effectiveness of the product was identified after the trial had begun. If the outcome of the trial is successful, the sponsor will ordinarily be able to rely on it as the basis for approval with respect to effectiveness. While we have received FDA’s agreement on a SPA for each of our two Phase 3 trials assessing GVAX immunotherapy for prostate cancer, there can be no assurance that these trials will have successful outcomes or that we will ultimately receive approval for this product. We currently manufacture GVAX immunotherapy for prostate cancer for Phase 3 clinical trials in our Hayward, California manufacturing facility, which operates in accordance with cGMP regulations, and plan to manufacture product for the potential market launch of this immunotherapy in the same facility. We have recently begun to develop a strategy to achieve optimal reimbursement for GVAX immunotherapy for prostate cancer and have conducted preliminary market research for this product.

In May 2006 the FDA granted Fast Track designation for GVAX immunotherapy for prostate cancer. Fast track designation, which was mandated by the FDA Modernization Act of 1997, can potentially facilitate development and expedite the review of Biologics License Applications ("BLAs"). Fast track designation is reserved for products that demonstrate the potential to treat a serious or life-threatening condition and demonstrate the potential to address unmet medical needs for that condition.

(The data referenced in the preceding paragraphs represent the most recently announced data pertaining to this program.)

Please visit the Patient Information section of this site to learn more about clinical trials currently open for enrollment.