Treatment of Prostate Cancer

Eligibility Details: Inclusion Criteria: - Be 18 years old at the time the informed consent is signed - Have a histologically or cytologically confirmed adenocarcinoma or poorly differentiated carcinoma of the prostate that is metastatic - Be surgically or medically castrated, with serum testosterone levels of ≤ 50 ng/dL (1.73 nM) - Be eligible for treatment with physician's choice of comparator treatment (abiraterone acetate, enzalutamide or docetaxel) - Experienced disease progression after having received 1 prior next generation androgen receptor-targeted therapy for castration-resistant disease - Have a deleterious mutation in a BRCA1/2 or ATM gene Exclusion Criteria: - Active second malignancy, with the exception of curatively treated non melanoma skin cancer, carcinoma in situ, or superficial bladder cancer - Prior treatment with any PARP inhibitor - Prior treatment with chemotherapy for metastatic castration-resistant prostate cancer - Symptomatic and/or untreated central nervous system metastases - Pre-existing duodenal stent and/or any gastrointestinal disorder or defect that would, in the opinion of the investigator, interfere with absorption of study drug