Lymph nodes greater than or equal to 1.5cm (short axis) are considered measurable disease bone disease progression defined by greater than or equal 2 new lesions on bone scan at Screening, or less than or equal 28 days of C1D1 7. Have received abiraterone and/or enzalutamide. Subject must have received either abiraterone or enzalutamide for greater than or equal to 12 weeks. Other second generation CYP17 inhibitors/androgen receptor antagonists including but not limited to TAK-700 (orteronel), TOK-001 (galeterone) may have been taken in place of abiraterone and ARN-509 (apalutamide) may have been taken in place of enzalutamide.