An Efficacy and Safety Study of Niraparib in Men With Metastatic Castration-Resistant Prostate Cancer and DNA-Repair Anomalies

This is a multicenter and open-label (participants and researchers are aware of the treatment
that participants are receiving) study that consists of 4 phases; a Prescreening Phase for
biomarker evaluation only, a Screening Phase, a Treatment Phase (Cycle 1 Day 1 and will
continue until the study drug is discontinued), and a Follow-up Phase (every 3 months after
end of treatment visit). Participants will be monitored for safety during the study period,
and up to 30 days after the last dose of study drug.

Inclusion Criteria:

- Histologically confirmed prostate cancer (mixed histology is acceptable, with the
exception of the small cell pure phenotype, which is be excluded)

- Received at least 1 line of taxane-based chemotherapy for the treatment of metastatic
castration-resistant prostate cancer (mCRPC) with documented evidence of disease
progression prior to enrollment

- Received at least 1 line of androgen receptor (AR)-targeted therapy (for example
{e.g.}, abiraterone acetate plus prednisone, enzalutamide, apalutamide) for treatment
of mCRPC with documented evidence of disease progression prior to enrollment

- Biomarker-positive for deoxyribonucleic acid (DNA)-repair anomalies

- Progression of metastatic prostate cancer in the setting of castrate levels of
testosterone or history of bilateral orchiectomy at study entry

Exclusion Criteria:

- Prior treatment with a poly (adenosine diphosphate [ADP] ribose) polymerase (PARP)
inhibitor

- Prior platinum-based chemotherapy for the treatment of prostate cancer

- Known history or current diagnosis of myelodysplastic syndrome (MDS)/acute myeloid
leukemia (AML)

- Symptomatic or impending cord compression

- Symptomatic brain metastases