Study Description:  The purpose of this study is to evaluate the effectiveness of study drug, niraparib in combination with abiraterone acetate and prednisone (AA-P) compared to AA-P plus placebo. This study will assess efficacy and safety of niraparib in combination with AA-P for the treatment of participants with metastatic prostate cancer.

Eligibility:

Inclusion Criteria:

• Adult Males (Age ≥ 18 years)
  • Positive for DNA-repair gene defects (DRD) status
    • Please reach out to study coordinator for testing
• Prior treatment with a poly adenosine diphosphate ribose polymerase (PARP) inhibitor
• Systemic therapy such as enzalutamide, apalutamide, or darolutamide; certain types of chemotherapy, or more than 4 months of abiraterone acetate plus prednisone [AA-P] after surgical or medical castration; or AA-P treatment for some other disease
• Symptomatic brain metastases
• History or current diagnosis of myelodysplastic syndrome (MDS)/acute myeloid leukemia (AML)
• Other prior cancers (exceptions: treated basal cell or squamous cell skin cancer, some bladder cancers, or any other cancer in complete remission) 2 years before start of the study, or malignancy that currently requires active therapy
• Uncontrolled pain or other medical conditions

• Metastatic disease documented by bone scan, computed tomography (CT) or magnetic resonance imaging (MRI)
• Metastatic prostate cancer with testosterone levels less than or equal to  50 ng/dL
• Able to continue hormone therapy during the study if not surgically castrated

   

  Exclusion Criteria:

• • Prior treatment with a poly adenosine diphosphate ribose polymerase (PARP) inhibitor
  • Systemic therapy such as enzalutamide, apalutamide, or darolutamide; certain types of chemotherapy, or more than 4 months of abiraterone acetate plus prednisone [AA-P] after surgical or medical castration; or AA-P treatment for some other disease
  • Symptomatic brain metastases
  • History or current diagnosis of myelodysplastic syndrome (MDS)/acute myeloid leukemia (AML)
  • Other prior cancers (exceptions: treated basal cell or squamous cell skin cancer, some bladder cancers, or any other cancer in complete remission) 2 years before start of the study, or malignancy that currently requires active therapy
  • Uncontrolled pain or other medical conditions