A Study of ZEN003694 in Patients With Metastatic Castration-Resistant Prostate Cancer

Inclusion criteria

• Males age ≥ 18 years
• Metastatic, castrate resistant, histologically confirmed prostate cancer; surgically castrated or continuous medical castration for ≥ 8 weeks prior to screening
• Serum testosterone < 50 ng/dL determined within 4 weeks of first administration of study drug
• Prior progression on one or more androgen-receptor/androgen-synthesis inhibitor therapies (e.g. abiraterone, enzalutamide, apalutamide, TAK-700 and/or galeterone) by Prostate Cancer Working Group 2 (PCWG2) criteria. Prior progression on bicalutamide/nilutamide/flutamide/ketoconazole alone is not allowed.
• Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1
• Adequate laboratory parameters [absolute neutrophil (ANC), platelets, aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin, creatinine and coagulation parameters] at screening

Exclusion criteria

• Any history of brain metastases or prior seizure or conditions predisposing to seizure activity
• Have previously received an investigational BET inhibitor (including previous participation in this study or Study ZEN003694-002)
• Have received prior systemic anti-cancer therapy or investigational therapy within 2 weeks or five half-lives, whichever is shorter, prior to the first administration of study drug
• Failure to recover to Grade 1 or lower toxicity related to prior systemic therapy (excluding alopecia and neuropathy) prior to study entry
• Radiation therapy within 2 weeks of first administration of study drug
• Have received prior chemotherapy in the metastatic castration-resistant setting (prior chemotherapy in the hormone-sensitive setting is allowed provided last dose was at least 6 months prior to study entry)
• Currently receiving medications known to be strong inducers or inhibitors of CYP3A4 with a narrow therapeutic window. Strong inducers and inhibitors of CYP3A4 with narrow therapeutic ranges must be discontinued at least 7 days prior to the first administration of study drug.