Abiraterone in heavily pretreated patients with metastatic castrate-resistant prostate cancer.

The aim of this study was to evaluate the activity and tolerability of abiraterone acetate in patients with metastatic castrate-resistant prostate cancer treated previously with more than three lines of chemotherapy. Patients received 1 g of abiraterone acetate (administered as four 250 mg tablets) orally once daily with prednisone at a dose of 5 mg orally twice daily. The primary endpoint was prostate-specific antigen (PSA) response. From August 2011 to January 2013, 36 patients were enrolled. PSA response was observed in 22 patients (61.1%, 95% confidence interval: 0.41-0.81). The median time to PSA progression was 7.3 months and after a median follow-up of 10.1 months, all patients were alive. The treatment was generally well tolerated; side effects secondary to mineralocorticoid excess resulting from blockade of CYP17 were largely controlled with prednisone. Abiraterone acetate seems to be an effective and well-tolerated treatment option for patients with metastatic castrate-resistant prostate cancer irrespective of the number of chemotherapy lines administered previously.