Phase I and II studies of the allogeneic prostate cancer vaccine have been performed in patients with metastatic prostate cancer. One is a Phase I trial of CG1940 alone and one is a phase I/II trial of CG1940 and CG8711 using the AAV GM-CSF vaccine cells. These trials are currently in progress to evaluate safety and time to progression by PSA and bone scan. In these trials the vaccines are administered at dose levels of 5 x 10^7, 1 x 10^8, 2 x 10^8, or 3 x 10^8 cells every 2 or 4 weeks for 3 to 12 vaccinations and a 5 x 10^8 cell prime vaccination followed by a 3 x 10^8 cell boost vaccination every 2 weeks for a total of 13 vaccinations. Preliminary analysis of the 12 patients enrolled in the phase I trial shows one patient with stable disease. Eighty patients have been enrolled in the phase II trial. Sixty-five of these patients in the phase II trial have been followed for a median of 4 months. One of these patients had a partial PSA response, and 10 maintained stable PSAs. Follow-up bone scans were obtained in 33 patients. One patient showed improvement in metastatic lesions on his bone scan, and 12 patients maintained stable disease on bone scans. ICTP was assayed at Treatment 1, Treatment 4, and at the First Follow-Up Visit in fifteen patients. The ICTP level decreased in five patients (33%) of whom two had undetectable levels after vaccine treatment. This normalization of osteoclast activity suggests a novel mechanism of immunotherapy in metastatic prostate cancer.