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

Inclusion Criteria:

1. Males age ≥ 18 years

2. Metastatic, castrate resistant, histologically confirmed prostate cancer; surgically
castrated or continuous medical castration for ≥ 8 weeks prior to screening

3. Serum testosterone < 50 ng/dL determined within 4 weeks of first administration of
study drug

4. 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.

5. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1

6. Adequate laboratory parameters [absolute neutrophil (ANC), platelets, aspartate
aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin, creatinine
and coagulation parameters] at screening

Exclusion Criteria:

1. Any history of brain metastases or prior seizure or conditions predisposing to seizure
activity

2. Have previously received an investigational BET inhibitor (including previous
participation in this study or Study ZEN003694-002)

3. 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

4. Failure to recover to Grade 1 or lower toxicity related to prior systemic therapy
(excluding alopecia and neuropathy) prior to study entry

5. Radiation therapy within 2 weeks of first administration of study drug

6. 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)

7. 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.