A JNJ-56021927 (ARN-509; Apalutamide) QT/QTc Study

This is an open-label (a study in which the drug, procedure is known to participant and
investigator), multicenter, Phase 1b study to investigate the effect of apalutamide on
ventricular repolarization at a dose level of 240 milligram (mg daily). Approximately 42
participants with high-risk non-metastatic prostate cancer (NM-CRPC), defined as having a
prostate specific antigen (PSA) doubling time less than or equal to (<=) 10 months, or
participants with metastatic CRPC will be enrolled. The study consists of a 28-day Screening
Phase, a Treatment Phase and a Follow-up Phase. In the Treatment Phase the study drug will be
administrated in cycles of 28 days and the participants will be monitored for safety
(including cardiac safety) and pharmacokinetics of the study drug. Adverse Events will be
monitored throughout the study and in the Follow-up Phase until 30 days after the last dose
of study drug. All participants will continue on study until disease progression, withdrawal
of consent, lost to follow-up, the occurrence of unacceptable toxicity, the participant is no
longer receiving clinical benefit in the opinion of the investigator, or termination of the
study by the sponsor. Upon discontinuation of study drug, the participants will return for an
End-of-Treatment (EoT) visit no later than 30 days after their last dose. The end of the
study is defined as 30 days after the last participants' last dose of study drug.

Inclusion Criteria:

- Eastern Cooperative Oncology Group (ECOG) performance status score of 0 or 1

- Adenocarcinoma of the prostate; either non-metastatic castrate resistant prostate
cancer (NM-CRPC) with high risk disease (defined as PSA Doubling time equal or less
than (<=) 10 months) or metastatic CRPC

- Be surgically or medically castrated with testosterone levels of less than (<) 50
nanogram per deciliter

- If treated with a gonadotropin releasing hormone analog (ie, patient who has not
undergone bilateral orchiectomy), then this therapy must have been initiated at least
4 weeks prior to Cycle 1 Day 1 and must be continued throughout the study

- Electrocardiogram (ECG) showing a QT interval corrected for heart rate, using
Fridericia formula (QTcF) <= 470 milliseconds (based on the average of a triplicate
ECG set collected during the screening visit)

- Left ventricular ejection fraction (LVEF) of more than 45% as determined by multiple
uptake gated acquisition (MUGA) or echocardiography at the screening visit

Exclusion Criteria:

- Abnormal cardiac function at screening

- Known brain metastases

- Has received an investigational drug within 4 weeks, or within a period < 10 times the
drug's half-life, whichever is longer, of Cycle 1 Day 1

- Has received chemotherapy or immunotherapy for the treatment of prostate cancer within
4 weeks of Cycle 1 Day 1

- Prior treatment with enzalutamide and apalutamide

- Use of therapies that must be discontinued or substituted within at least 4 weeks
prior to Cycle 1 Day 1 including medications to lower seizure threshold,
inducing/inhibiting metabolizing enzymes or prolonging the QT interval

- History or condition that may predispose to seizures, or evidence of severe or
unstable angina, myocardial infarction, symptomatic congestive heart failure, arterial
or venous thromboembolic events within 12 months prior to Cycle 1 Day 1, New York
Heart Association (NYHA) Class II to IV heart disease