A prospective phase-II trial of biweekly docetaxel plus androgen deprivation therapy in patients with previously-untreated metastatic castration-naïve prostate cancer.

INTRODUCTION: The aim of this prospective phase II study was to evaluate the efficacy and safety of biweekly docetaxel plus androgen-deprivation therapy (ADT) in patients with metastatic castration-naïve prostate cancer (mCNPC).

PATIENTS AND METHODS: Patients with histologically-proven, previously-untreated mCNPC received ADT plus docetaxel, 40 mg/m2. Docetaxel was repeated every 2 weeks, up to 12 cycles. Endpoints included castration-resistant prostate cancer (CRPC)-free survival, prostate-specific antigen (PSA) response, and safety.

RESULTS: A total of 42 patients were registered and analyzed for final outcomes. Of the 42 patients, 36 (86%) completed the 12 planned cycles of docetaxel plus ADT. During a median follow up of 25 months, all but two patients (95%) achieved a PSA response with a nadir PSA level of 0.42 ng/ml (range 0.01-1280.87). The median CRPC-free survival was 26.4 months (95% confidence interval [CI] 20.9-32.0) with a one-year CRPC-free rate of 79% (33 patients, 95% CI 66-91). Multivariable analysis revealed that the performance status of the Eastern Cooperative Oncology Group 0 was independently associated with longer CRPC-free survival (hazard ratio [HR] 0.27, 95% CI 0.07-0.99). The most common adverse events of any grade were anemia (95%), followed by nail changes (33%), fatigue (29%), and oral mucositis (26%). Severe (grade 3 or higher) adverse events were infrequent: pneumonitis (n = 2), diarrhea (n = 1), and neutropenia (n = 1).

CONCLUSION: Our results suggest that biweekly docetaxel plus ADT is feasible, and clinical efficacy does not seem to be compromised compared to a standard triweekly docetaxel 75 mg/m2 plus ADT regimen.