Phase II trial of cisplatin plus prednisone in docetaxel-refractory castration-resistant prostate cancer patients

Background: Docetaxel represents the first-line treatment for castration-resistant prostate cancer (CRPC). New therapeutic options are needed for subsequent lines of therapy in CRPC patients. Methods: Patients with progressive CRPC, pretreated with docetaxel, were enrolled at the Department of Molecular and Clinical Oncology and Endocrinology of University 'Federico II of Naples' from April 2007 to January 2010. Accrued patients received cisplatin at the dose of 75 mg/m² every 3 weeks with daily 10 mg prednisone. Measures of response and progression were defined according to the Prostate Cancer Working Group (PCWG1) criteria. Toxicity was graded according to the Common Toxicity Criteria of the National Cancer Institute, version 3.0. Results: Twenty-five patients were recruited. Median age was 65 years (interquartile range 55-74 years). All patients were evaluable for PSA response and toxicity and thirteen patients (52%) were evaluable for measurable disease. A total of 170 cycles of cisplatin chemotherapy were administered. Median dose intensity corresponded to 96% (range 83.8-98.3%) of the maximum dose intensity that could be delivered. Three patients (12%) presented grade 3-4 neuropathy and ten (40%) presented grade 3-4 neutropenia. Five patients (20%) showed a greater than 50% PSA decline, and three of thirteen patients with measurable disease presented a partial response. Median progression-free survival was 5.6 months (24 weeks; range 15-24). Median survival was 55 weeks (range 46-64; see Fig. 1). Conclusions: Cisplatin plus prednisone appears to represent an active regimen in docetaxel-refractory CRPC with an acceptable toxicity profile. Further investigations in this setting are warranted to confirm these early encouraging findings.