Cabozantinib Versus Mitoxantrone-prednisone in Symptomatic Metastatic Castration-resistant Prostate Cancer: A Randomized Phase 3 Trial with a Primary Pain Endpoint.

Background: Bone metastases in patients with metastatic castration-resistant prostate cancer (mCRPC) are associated with debilitating pain and functional compromise.

Objective: To compare pain palliation as the primary endpoint for cabozantinib versus mitoxantrone-prednisone in men with mCRPC and symptomatic bone metastases using patient-reported outcome measures.

Design, Setting, And Participants: A randomized, double-blind phase 3 trial (COMET-2; NCT01522443) in men with mCRPC and narcotic-dependent pain from bone metastases who had progressed after treatment with docetaxel and either abiraterone or enzalutamide.