Prognostic Factors For Patients With Metastatic Castrate-Resistant Prostate Cancer (Mcrpc) Receiving Abiraterone Acetate Prechemotherapy.

e16054 Background: Abiraterone acetate is an androgen biosynthesis inhibitor which has shown response in patients with mCRPC treated prior to docetaxel chemotherapy ( Raj et al New Eng J med 2013). Prognostic factors have limited data. Methods: Retrospective review was undertaken of patients with mCRPC treated with abiraterone 1g daily pre-chemotherapy. Response was defined as u003e 50% reduction in PSA. PFS and OS were assessed. Established prognostic factors in mCRPC were explored. Results: 93 patients were identified. Median age was 73 years (55-90). Treatment was discontinued in 3/93 patients due to diarrhoea, one permanently. Dose reductions to 500mg od were seen in 2/93 (1: hypertension; 1 skin reaction) with biochemical response maintained. 42 /86 (49%) assessable patients had a PSA response to abiraterone ≥50% 44/86 (51%) patients have not yet progressed Median PFS is 208 days (95% CI 135-281) 18/93 patients have died. Median survival is not reached. Median 1 year survival is 76.2% (95% CI 86.6 - 65.8...