Fifteen patients with previously untreated metastatic prostate cancer were treated on a pilot trial with a combination of maximal androgen blockade plus intermittent cytotoxic therapy after androgen priming to stimulate cell division. Androgen blockage was carried out using a gonadotropin-releasing hormone analog (leuprolide) plus a nonsteroidal antiandrogen (flutamide). Carboplatin (CBDCA) (800 mg/m2) was given intravenously every 28 days, preceded for 3 days and followed for 3 days by androgen treatment with fluoxymesterone (5 mg orally twice a day), during which time flutamide was discontinued. Three patients (20%) achieved a complete response (CR), and eight patients (53.3%) achieved a partial response (PR). Four patients (26.7%) had stable disease (SD). The median progression-free survival (PFS) time was 31 months. Nine of 15 patients (60%) remain alive with a median follow-up time of 42+ months (range, 22 to 54 months). Grade 4 thrombocytopenia and Grades 3 or 4 leukopenia were experienced in 87% and 80% of patients, respectively, requiring dose reductions of CBDCA in 85% of the cycles. Six of 15 patients experienced a flare in bone pain with androgen priming. There were no associated spinal cord compressions; however, exclusion of impending spinal cord compression was required before entrance on study.