RATIONALE: Vaccines may make the body build an immune response to kill tumor cells. It is not yet known if vaccine therapy is effective for prostate cancer.

PURPOSE: Randomized phase III trial to determine the effectiveness of vaccine therapy in treating patients who have metastatic prostate cancer that has not responded to hormone therapy.

OBJECTIVES: I. Compare the time to progression, time to development of disease-related pain, and incidence of grade 3 or worse treatment-related adverse events in patients with asymptomatic metastatic hormone refractory adenocarcinoma of the prostate treated with APC8015 versus control infusion. II. Compare response rate and duration of response in these patients.

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.

PROJECTED ACCRUAL: A total of 120 patients (80 in arm I and 40 in arm II) will be accrued for this study.

• Biological: prostatic acid phosphatase-sargramostim fusion protein
• Biological: sipuleucel-T
• Procedure: in vitro-treated peripheral blood stem cell transplantation
• Procedure: peripheral blood stem cell transplantation

• Small EJ, Schellhammer PF, Higano CS, Redfern CH, Nemunaitis JJ, Valone FH, Verjee SS, Jones LA, Hershberg RM. Placebo-controlled phase III trial of immunologic therapy with sipuleucel-T (APC8015) in patients with metastatic, asymptomatic hormone refractory prostate cancer. J Clin Oncol. 2006 Jul 1;24(19):3089-94.
• Higano CS, Schellhammer PF, Small EJ, Burch PA, Nemunaitis J, Yuh L, Provost N, Frohlich MW. Integrated data from 2 randomized, double-blind, placebo-controlled, phase 3 trials of active cellular immunotherapy with sipuleucel-T in advanced prostate cancer. Cancer. 2009 Aug 15;115(16):3670-9.

DISEASE CHARACTERISTICS: Histologically proven hormone refractory adenocarcinoma of the prostate that is asymptomatic Must have soft tissue and/or bony metastases No visceral organ metastases (e.g., liver, lung, brain) or cytologically positive effusions (e.g., pleural effusions or ascites) At least 25% of tumor cells staining positive for prostatic acid phosphatase by immunohistochemistry PSA at least 5 ng/mL Tumor progression after hormonal therapy No cancer related pain and no regular requirement for analgesics

PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0 or 1 Life expectancy: At least 16 weeks Hematopoietic: WBC at least 2,000/mm3 Absolute neutrophil count at least 1,000/mm3 Platelet count at least 100,000/mm3 Hemoglobin at least 9.0 g/dL Hepatic: Bilirubin no greater than 2 times upper limit of normal (ULN) ALT and AST no greater than 5 times ULN Hepatitis B surface antigen and hepatitis C antibody negative Renal: Creatinine no greater than 2.0 mg/dL Other: HIV1, HIV2, and HTLV-1 negative No active bacterial, viral, or fungal infection No other malignancy except: Basal cell or squamous cell skin cancer within the past 3 years OR Stage I or II other cancers within the past 5 years No psychologic, familial, sociologic, geographic, or other medical condition that would preclude study

PRIOR CONCURRENT THERAPY: Biologic therapy: No prior biologic therapy Chemotherapy: No more than 1 prior chemotherapy regimen Endocrine therapy: See Disease Characteristics More than 1 year since prior corticosteroids except replacement systemic steroids and inhaled, intranasal, or topical corticosteroids No concurrent antiandrogen therapy Concurrent LHRH agonists allowed Radiotherapy: No prior radiopharmaceutical therapy At least 4 weeks since other prior radiotherapy and recovered Surgery: At least 4 weeks since prior surgery and recovered Other: No concurrent herbal therapy Concurrent bisphosphonates allowed if started at least 30 days before enrollment and continued for duration of study