Phase II trial of estramustine phosphate and oral etoposide in patients with hormone-refractory prostate cancer

There is a need for active agents with a better safety profile than docetaxel, yet good activity, for patients with hormone-refractory prostate cancer (HRPC). We carried out a phase II trial to determine the activity and safety of estramustine plus oral etoposide in HRPC.

Patients were given estramustine (280 mg twice daily) and etoposide (100 mg/day, days 1-21) in 28-day cycles until disease progression or unacceptable toxicity. Primary end points were overall response rate and safety, as determined by prostate-specific antigen (PSA) levels and lesion assessment.

From November 2001 to February 2007, 75 patients were enrolled. All patients were assessable for safety; 17 (22.6%) had grade 3/4 toxicity. PSA response was assessable in 69, 14 of whom had a >50% reduction in PSA. Of 10 patients with one or more measurable lesions, two (20%) had partial response and two (20%) disease stabilization. Overall, median time to progression was 4.4 months (range 1 week-43 months); median survival was 23 months (range 3 weeks-64+ months).

Estramustine plus etoposide is active and has a manageable safety profile in patients with HRPC. In asymptomatic patients with nonaggressive disease this combination could be useful to delay the start of more demanding treatments.