This is a randomized (study drug assigned by chance), double-blind (neither the Investigator nor the participant know the treatment) placebo-controlled and multicenter (when more than 1 hospital or medical school team work on a medical research study) study to determine if participants with chemotherapy-naive mCRPC will benefit from the addition of apalutamide to AAP compared with AAP alone. The study consists of 3 phases: Screening phase; Treatment phase, and Follow-up phase. At the final analysis, the study will be unblinded. After the Independent Data Monitoring Committee (IDMC) review and the sponsor's subsequent decision participants will be offered to receive treatment either in the Open-Label Extension Phase or the Long-Term Extension Phase of study. Participants' safety will be monitored throughout the study.
