A phase II Hoosier Oncology Group study of vinorelbine and estramustine phosphate in hormone-refractory prostate...

The purpose was to evaluate the combined anti-microtubular regimen of vinorelbine and estramustine phosphate (EMP) in hormone refractory prostate cancer.

Weekly vinorelbine 20 mg/m2 (or 15 mg/m2 if a history of prior pelvic radiotherapy) was combined with EMP at 280 mg orally tds for 3 days (the day before, the day of and the day after vinorelbine infusion). After 8 weeks of therapy the combination was given every other week.

From February 1998 to February 1999, 23 men were enrolled with a median age of 69 years (range 50-83 years). The median prostate-specific antigen (PSA) at entry was 160 ng/ml (range 0-802 ng/ml). A median of 13 weeks of therapy was administered and the median follow-up was 14.8 months. Eleven patients (48%) had lower extremity edema requiring diuretic therapy, two (9%) had grade 2 granulocytopenia and four patients [17%; 95% confidence interval (CI) 5% to 39%] had a thromboembolic episode. There was no treatment-related mortality. Fifteen of 21 patients (71%; 95% CI 49% to 89%) had at least a 50% decrease in the PSA for at least 2 months with a median time to serologic progression of 3.5 months (range 0.75-10.5 months). One of eight patients (12.5%; 95% CI 0% to 53%) with measurable disease had a confirmed partial response. The estimated median survival was 15.1 months and the actual one year overall survival was 71% (95% CI 51% to 88%).

Weekly vinorelbine with short course oral EMP is an active regimen as evaluated by rate of PSA response, time to progression and median survival. However, the toxicities of EMP, even when given as a short course, are still problematic.