Final Analysis Comet-2: Cabozantinib (Cabo) Versus Mitoxantrone/Prednisone (Mp) In Metastatic Castration-Resistant Prostate Cancer (Mcrpc) Patients (Pts) With Moderate To Severe Pain Who Were Previously Treated With Docetaxel(D) And Abiraterone (A) And/Or Enzalutamide (E)

141 Background: Cabo inhibits tyrosine kinases including MET and VEGFRs. In a phase 2 study in mCRPC pts, Cabo was associated with improvements in pain, bone scans, measurable disease, and circulating tumor cells. COMET-2 compared the effects of Cabo versus MP on pain palliation in men with progressive mCRPC. Methods: In this double-blind, controlled phase 3 study (NCT01522443), pts with moderate to severe pain and disease progression following D, and A and/or E were randomized 1:1 to receive Cabo (60 mg qd) or MP (12 mg/m2 q3wk and 5 mg bid, resp). All pts were required to have a 7-day average of 4+ pain per Brief Pain Inventory (BPI) item 3 while on an optimized narcotics regimen at baseline. Randomization was stratified by prior cabazitaxel and ECOG performance status. The primary endpoint was pain response (≥30% reduction in BPI item 3) at week 6, confirmed at week 12, without increase in narcotics. The original sample size (N = 246) was selected to achieve at least 90% power to detect an increase in ...