Abiraterone Acetate in Patients with Advanced Castrate Resistant Prostate Cancer: Initial Real Life Experience in 2 Cancer Units

Introduction : Abiraterone Acetate (AA) improves outcome of patients with castrate resistant prostate cancer (CRPC) and is currently recommended for chemo-naA¯ve patients and after progression on chemotherapy. We reviewed our initial experience with the use of AA in these patients. Patients and Methods : Forty six consecutive CRPC patients were treated with AA 1000 mg/day and prednisolone 5 mg twice daily in 2 cancer centres in England and Saudi Arabia. Treatment was continued until disease progression or unacceptable toxicity. Patients achieving prostate specific antigen decline (PSA) ≥ 50% were considered as marker responders. Results : Median age was 76 (52-91) years. 28 and 18 patients received AA in pre-chemotherapy and post-chemotherapy setting respectively. PSA marker response was achieved in 56.1% (23/41) assessable patients. Objective radiological response rate was seen in 31.6% (6/19) and stable disease in 15.8% (3/19) assessable patients. After a median follow up of 20 months, median time to PSA progression was 12 months (95% CI: 9.5-14.5) and median overall survival was not reached (mean = 21 months, 95% CI: 18-24.5). Toxicity was assessed in 18 patients. All grades adverse events of special interest were hypokalaemia (22%) and hypertension (11%). Conclusion : In daily clinical practice, AA is an effective treatment for patients with CRPC. It produces meaningful marker and objective responses, marker progression free survival and OS that are comparable to those reported in clinical trials. Monitoring of blood pressure and serum potassium is recommended.