(UroToday.com) Metastatic castration resistant prostate cancer (mCRPC) continues to be driven by androgen signaling, but this patient population has heterogeneous responses to second-generation androgen pathway inhibitors. Apalutamide, an androgen receptor antagonist, and abiraterone acetate, and androgen synthesis inhibitor, have somewhat distinct mechanisms of action and efficacy in mCRPC. The ACIS trial (NCT02257736) was designed to study is the combination of these two therapies, termed androgen annihilation, as first-line therapy in mCRPC.