Outline: This is a randomized study. Patients are randomized to one of two treatment arms. Arm I: Autologous dendritic cell precursors (ADCP) are harvested on weeks 0, 2, and 4. Patients receive APC8015 comprised of ADCP activated with prostatic acid phosphatase-sargramostim (GM-CSF) fusion protein IV over 30 minutes beginning 2 days after each harvest for a total of 3 infusions. Arm II: ADCP are harvested as in arm I. Patients receive unactivated ADCP IV over 30 minutes beginning 2 days after each harvest for a total of 3 infusions. Pain is assessed weekly for up to 3 years or until 4 weeks after objective disease progression. Patients are followed monthly for up to 3 years or until disease progression. At the time of disease progression, patients treated on arm II may receive treatment on Protocol D9903.