Pain control and delay in time to skeletal-related events (SREs) in patients with metastatic castration-resistant prostate cancer (mCRPC) treated with abiraterone acetate (AA): Long-term follow-up.

183 Background: In study COU-AA-301, the androgen biosynthesis inhibitor AA significantly increased overall survival in mCRPC post-docetaxel (D) in both interim and updated analyses at 552 and 775 events, respectively. Interim data also showed a significant benefit of AA on patient (pt) reported pain. We present long-term outcomes of the effect of AA on pain and SREs. Methods: In this international randomized double blind study of AA (1 g QD) + prednisone (P) (5 mg BID) vs placebo + P in mCRPC post-D, pain was assessed at baseline and each treatment cycle until treatment discontinuation using the BPI-SF questionnaire. Palliation/progression of pain intensity (P-INT) and pain interference (P-INF) were evaluated using a priori definitions. P-INT palliation was defined as ≥ 30% improvement in pt reported “worst pain in last 24 h” (on 0-10 numerical rating scale) durable for ≥ 28 d without increased analgesic use (by WHO criteria) in eligible pts (those with significant baseline pain). Conversely, P-INT progr...