Throughout the study, safety and tolerability will be assessed by the recording of adverse events, monitoring of vital signs and physical examinations, safety laboratory evaluations, and 12-lead electrocardiograms (ECGs). Subjects will have a safety follow-up visit 30 days after their last dose of study drug. Subjects that have not met any of the discontinuation criteria may be eligible to continue to receive treatment with enzalutamide in Study 9785-CL-0123 upon approval and activation of this study at the participating institution. Subjects who enroll in Study 9785-CL-0123 will not be required to have a safety follow-up visit.