DISEASE CHARACTERISTICS: Histologically proven metastatic adenocarcinoma of the prostate, defined by: Abnormal CT, MRI, or bone scan and/or Rising prostate specific antigen (PSA) levels (on 3 consecutive occasions over at least 6 weeks) despite hormonal therapy PSA at least 2.0 at study entry No active CNS metastases

PATIENT CHARACTERISTICS: Age: 21 and over Performance status: Karnofsky 60-100% Life expectancy: At least 6 months Hematopoietic: WBC greater than 3,500/mm3 Platelet count greater than 100,000/mm3 No serious hematologic disease Hepatic: SGOT less than 2.0 times upper limit of normal Bilirubin less than 1.5 mg/dL No serious hepatic disease Renal: Creatinine less than 2.0 mg/dL Calcium less than 13.5 mg/dL No serious renal disease Cardiovascular: No active angina No New York Heart Association class III-IV No other serious cardiac disease Pulmonary: No serious respiratory disease Other: No active uncontrolled infection Evidence of pre-existing antimouse antibody at the time of screening

PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: At least 6 weeks since prior cytotoxic chemotherapy Endocrine therapy: At least 6 weeks since prior adrenal hormone inhibitors or corticosteroid therapy Antiandrogen therapy must be discontinued prior to measuring PSA values Luteinizing hormone-releasing hormone analog must be maintained during study OR must be discontinued at least 10 weeks prior to study entry (for 28 day depot preparation) or 24 weeks prior to study entry (for 3 month depot preparation) Radiotherapy: At least 6 weeks since prior radiotherapy Surgery: Not specified