Low-dose metronomic oral cyclophosphamide plus prednisone for castration resistant prostate cancer (CRPC): A retrospective study.

Abstract

e16095 Background: CRPC remains a therapeutic challenge, although in recent years the introduction of new agents has allowed an improvement in overall survival of these patients. In the literature there are few data on the use of cyclophosphamide in this context. The current study was designed to evaluate the efficacy and toxicity of the metronomic oral administration of a combination of cyclophosphamide and prednisone in patients with CRPC, not candidates for docetaxel or after progression to it. Methods: We retrospectively evaluated the medical records of all patients with metastatic CRPC who were treated with prednisone and cyclophosphamide in our institution. Patients had been previously treated with a docetaxel-containing regimen or were not considered candidates for taxanes, because of important comomorbidities or poor Performance Status (PS). Results: Data from 40 patients treated with cyclophosphamide 50 mg/day vo and prednisone 5 mg bid from January 2010 to December 2012 has been analyzed. Baseline characteristics of the patients are listed in the Table. 36 patients were evaluable for efficacy and toxicity. The PSA response rate (RR) was 30%, with partial responses in 7/40 patients. The clinical benefit (stabilization disease + RR) was 52%. Median progression-free survival was 13 weeks (95% CI 13.2 – 14.5). Median overall survival was 46 weeks (95% CI 26.4 – 65.9). The overall 1-year and 2-year survival were 32% and 8 %, respectively. The treatment was safe and well tolerated. Anemia (grade 0-3) was observed in a third of all patients. Conclusions: In this study in patients with a poor prognosis, metronomic oral cyclophosphamide plus prednisone have demonstrated efficacy with excelent tolerance. Oral cyclophosphamide is an interesting alternative to consider in patients non candidates for intravenous chemotherapy. [Table: see text]