Estramustine and vinblastine for patients with progressive androgen-independent adenocarcinoma of the prostate

A phase II trial was performed to assess antitumor activity and toxicity of estramustine and vinblastine in 31 consecutive patients with androgen-independent prostate cancer. All patients presented with disease progression following castrate serum testosterone levels of less than 50 ng/dl and were treated for 6 consecutive weeks with three daily 140-mg doses of oral estramustine and vinblastine at 6 mg/m2 weekly by intravenous bolus. Prostate specific antigen (PSA) levels decreased by greater than 50% from baseline in 13 (46%; 95% confidence intervals, 27%–66%) of 28 evaluable patients. Patients who demonstrated a greater than 50% reduction in PSA had a longer delay in time to disease progression. Nonhematologic toxicity was mild, predominantly gastrointestinal. Hematologic toxicity was apparent in 13 patients with grade III granulocytopenia and in 7 patients with grade IV granulocytopenia. No patient was admitted to the hospital for neutropenic fever. Estramustine and vinblastine is a well-tolerated combination. This combination and the clinical significance of this decline in PSA warrants further investigation.