Original articleThe efficacy of abiraterone acetate in treating Taiwanese chemo-refractory metastatic castration-resistant prostate cancer patients

ObjectiveTo evaluate the efficacy of abiraterone acetate in combination with prednisolone in Taiwanese men with metastatic castrate-resistant prostate cancer (mCRPC) who failed docetaxel-based chemotherapy.Materials and methodsIn this single-arm, open label study, 30 mCRPC patients with prostate specific antigen (PSA) progression after docetaxel chemotherapy were enrolled. All patients were treated with abiraterone acetate 1000 mg once daily and prednisolone 5 mg twice daily. The primary end-point was PSA response rate (defined as proportion of patients achieving a PSA decline of ≥50%). Secondary end-points were overall survival and time-to-PSA progression.ResultsAmong 28 patients who received one or more cycles of treatment, 15 (53.6%) men achieved PSA response [95% confidence interval (CI) 33.9-72.5]. The median time-to-PSA progression was 5.5 months (95% CI 3.1-7.9). The median interval from stopping abiraterone to death was 3.4 months (95% CI 0.1-21.0), and the median overall survival was 19.2 months (95% CI 13.0-25.4). The PSA responders had better overall survival compared with PSA nonresponders, in both univariate (log rank test, p = 0.007) and multivariate (Cox regression, p = 0.001; relative risk: 0.31; 95% CI: 0.12-0.76) analysis. Both a high Gleason score (≥8) and viscera involvement did not have an unfavorable response to abiraterone treatment.ConclusionA combination of abiraterone acetate and prednisolone can improve the overall survival in Taiwanese mCRPC patients who fail prior docetaxel chemotherapy.