( SOUTH SAN FRANCISCO Calif. April 17...)Cell Genesys Reports GVAX Immunotherapy for Prostate Cancer Induces,a Broad, Patient-Specific Antibody Response,Health

SOUTH SAN FRANCISCO, Calif., April 17, 2007 /PRNewswire-FirstCall/ -- Cell Genesys, Inc. today reported immune response data from two previously conducted Phase 2 clinical trials of GVAX immunotherapy for prostate cancer. Evaluation of antibody responses in patients with advanced prostate cancer from these studies shows that the GVAX cell-based immunotherapy induces antibody responses to a broad array of prostate cancer- associated antigens, including some not previously known to be associated with prostate cancer. In addition, the antibody responses to this non patient- specific product were predominantly patient-specific and unique from patient to patient, indicating the potential advantage of a cell-based multi-antigen product such as GVAX to generate the broadest and most relevant immune response. Serological analysis of gene expression (SEREX) technology was also used to identify target antigens involved in response to the immunotherapy. More than 148 proteins to which antibody responses were induced were identified and many of these proteins had not been identified previously as prostate cancer-associated antigens. These findings were presented today by Dr. Thomas Harding and colleagues from Cell Genesys at the annual meeting of the American Association for Clinical Research being held in Los Angeles, CA.

GVAX immunotherapy for prostate cancer is currently being studied both as a single agent and in combination with docetaxel chemotherapy in two Phase 3 clinical trials targeted to enroll approximately 1200 patients with metastatic hormone-refractory prostate cancer (HRPC). This ongoing Phase 3 program is supported by the median survival results from two, independent, multi-center Phase 2 clinical trials. Cell Genesys recently reported final, updated results from its second multi-center Phase 2 trial of GVAX immunotherapy for prostate cancer, which evaluated escalating doses of the immunotherapy in
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