Exploration Of The Utility Of Alkaline Phosphatase Level (Alp) As A Prognostic Factor In Patients With Metastatic Castrate Resistant Prostate Cancer (Mcrpc) Receiving Prechemotherapy Abiraterone Acteate.

e16039 Background: Abiraterone acetate is an androgen biosynthesis inhibitor with proven efficacy in patients with mCRPC treated prior to docetaxel chemotherapy (COU-AA-302 trial PSA PFS 11.1 months [Raj et al New Eng J med 2013] ). In a group of 93 patients, we report an exploratory analysis of rate of rise in alkaline phosphatase on response and survival. 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. ALP rise of u003e100 U/L 3 months pre treatment was explored as a predictive and prognostic factor, both independently and in conjunction with other predictive factors by multivariate analysis. Results: On multivariate analysis ALP rise u003e100 U/L in the three month period prior to dosing was independently prognostic for reduced overall survival (p=0.004). Median 1 year survival for patients without (n=69) or with (n=19) ALP rise was 87% (95% CI 77.8-96.2) and 39% (95...