A Phase 2 Efficacy and Safety Study of Niraparib in Men with Metastatic Castration-Resistant Prostate Cancer and DNA-Repair Anomalies

The purpose of this study is to assess the efficacy, safety, and pharmacokinetics of
niraparib in men with metastatic castration-resistant prostate cancer (mCRPC) and
deoxyribonucleic acid (DNA) repair anomalies.

Inclusion Criteria:

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

- Received a taxane-based chemotherapy for the treatment of metastatic prostate cancer
with evidence of disease progression on or after treatment, or discontinued from a
taxane-based chemotherapy due to an adverse event

- Received a second-generation or later androgen receptor (AR)-targeted therapy (for
example, abiraterone acetate plus prednisone, enzalutamide, apalutamide) for the
treatment of metastatic prostate cancer with evidence of disease progression or
non-metastatic castration-resistant prostate cancer with evidence of subsequent
metastasis

- Biomarker-positive by at least one of the following criteria: (a) Biallelic
deoxyribonucleic acid (DNA)-repair anomaly based on a sponsor validated blood or
tissue assay; (b) Germline pathogenic Breast Cancer gene (BRCA) 1 or BRCA2 by any test
(somatic local results must be confirmed as positive by the sponsor-validated assay
before dosing)

- 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