LAUSR

165Background: This phase 4, multicenter, single-arm, open-label study evaluated the efficacy and safety of ENZA in patients (pts) with progressing mCRPC previously treated with Abi. Methods: All pts maintained castration therapy with luteinizing hormone-releasing hormone for the duration of the trial or had a bilateral orchiectomy. Pts were required to have progressive disease at study entry and ≥ 24 weeks of Abi treatment prior to receiving 160 mg/day ENZA. Prior chemotherapy was allowed. The primary end point was radiographic progression-free survival (rPFS). The secondary end points were overall survival (OS), prostate-specific antigen (PSA) response, and time to PSA progression. Safety was also assessed. Results: A total of215 pts were enrolled; 214 were treated with ENZA (median age, 73 years). The analysis was performed on data up to 48 weeks after the last pt started ENZA treatment. Median duration of prior Abi therapy was 54 weeks. The median duration of ENZA treatment was 5.7 months: 12 months i...