Background: Recent clinical trials have shown antitumor activity with the combination of docetaxel plus estramustine phosphate (EMP) in the treatment of patients with androgen independent prostate carcinoma (AIPC). However, the most commonly employed treatment schedules with EMP have been associated with significant gastrointestinal, cardiovascular, and thromboembolic toxicity. The authors hypothesized that the therapeutic index of the combination of docetaxel plus EMP for patients with prostate carcinoma could be enhanced by reducing the incidence and severity of EMP-associated toxicity, which could be accomplished by shortening the duration of exposure to EMP. To preserve the therapeutic synergism between docetaxel and EMP, they designed a regimen employing higher doses of oral EMP administered on the day of the docetaxel infusion.
Methods: From June 1, 1998 through September 28, 2000, 42 patients with AIPC were registered to receive docetaxel (70 mg/m2 intravenously over 1 hour) and EMP (280 mg orally every 6 hours x 5 doses) every 21 days, up to a maximum of 6 cycles. Dexamethasone was administered prior to docetaxel and coumadin 2 mg orally every day was taken during the study treatment period. Patient characteristics included a median age of 68 years, a median Eastern Cooperative Oncology Group performance status of 1, a median prostate specific antigen (PSA) level at study entry of 110.5 ng/mL, and a median of 2 prior hormonal manipulations. Ten patients (25%) had received prior chemotherapy, and 14 patients (33%) had received prior palliative radiation therapy.
Results: Forty patients were evaluable for response and toxicity. Eighteen patients (45%; 95% confidence interval, 29-62%) had a decline > 50% in PSA level that lasted > 4 weeks with a median time to PSA progression and a median duration of PSA response of approximately 4.0 months. Four of 20 patients (20%) had partial soft tissue responses. Ten of 17 symptomatic patients (59%) had improvement in pain. The median survival for all patients was 13.5 months. The most prominent Grade 3 and 4 toxicities were reversible myelosuppression and fatigue. Nausea, emesis, diarrhea, and peripheral edema were minimal. No thromboembolic or hepatic complications were seen.
Conclusions: Docetaxel plus 1 multidose day of oral EMP was active in patients with AIPC and was associated with an acceptable toxicity profile. Overall, the therapeutic index of this regimen compared favorably with regimens that employed a longer administration of EMP.
Copyright 2002 American Cancer Society.