LAUSR

5010Background: The Phase 3 PROSPER trial (NCT02003924) showed a statistically significant improvement in metastasis-free survival (MFS) with enzalutamide (ENZA; n = 933) vs. placebo (PBO; n = 468) in asymptomatic men with M0 CRPC and prostate-specific antigen doubling time ≤10 months. We report the results of the HRQoL and pain evaluations. Methods: Functional Assessment of Cancer Therapy–Prostate (FACT-P) and Brief Pain Inventory, Short Form, were used to assess HRQoL and pain at baseline (BL) and every 16 weeks during treatment. Pain progression was defined as ≥2 points in pain severity items and mean scores increase from BL; HRQoL improvement/deterioration as an increase/decrease from BL using pre-established thresholds for clinically meaningful difference. Time to first confirmed (at two consecutive visits) and unconfirmed HRQoL deterioration/pain progression were assessed using Kaplan-Meier estimates and Cox proportional hazards models under censoring not at random assumption. Results: BL characteri...