A Study of Apalutamide (JNJ-56021927, ARN-509) Plus Androgen Deprivation Therapy (ADT) Versus ADT in Participants With mHSPC

This is a randomized (study medication assigned to participants by chance), double-blind (neither the researchers nor the participants know what treatment the participant is receiving), placebo-controlled, multinational, multicenter study of apalutamide in participants with mHSPC. The study consists of 4 Phases: Screening Phase (up to 28 days before randomization), Treatment Phase (28 day treatment cycles until disease progression or the occurrence of unacceptable treatment related toxicity), an End of Treatment Phase (until 30 days after the last dose of study drug), and then a Survival Follow up Phase. In the event of a positive study result and notification of unblinding at either of the interim analyses or at the final analysis, participants in the treatment Phase will have the opportunity to enroll in an Open-label Extension Phase, which will allow participants to receive active drug (apalutamide) for approximately 3 years. Participants who are receiving apalutamide in the Open-label Extension Phase may continue receiving apalutamide in the Long-term Extension (LTE) Phase if they will continue to derive benefit from treatment (based on investigator assessment). Participants' safety will be monitored throughout the study.