A Safety Study of JNJ-56021927 in Participants With Metastatic Castration-Resistant Prostate Cancer

This is a Phase 1, multicenter, open-label (participants will know the identity of study drug received) study in participants with Metastatic Castration-Resistant Prostate Cancer (mCRPC). The study consists of 4 parts: Screening (28 days before study commences on Day 1), pharmacokinetic week (PK), Continuous daily dosing, Extension and Safety follow-up period. In PK week participants will receive a single oral capsule of JNJ-56021927 at a dose of 240 milligram (mg) on Day 1 and will be monitored for 1 week. After Week 1, in continuous daily dosing period, participants will receive continuous daily therapy at the same dose for 4 weeks (Cycle 1). After Cycle 1 participants, who will not meet the criteria for discontinuation listed such as progressive disease (PD) or unacceptable toxicity, will continue in safety follow-up period and will receive continuous daily therapy at the same dose up to cycle 13. Primarily dose limiting toxicity (DLT) will be evaluated. Participants' safety will be monitored throughout.