Race Impact on Efficacy of Niraparib Plus Abiraterone Acetate and Prednisone in Patients With Homologous Repair Deficient Castration-resistant Prostate Cancer

This study will enroll up to 70 participants, divided into two cohorts of 35 each. Cohort A will include participants self-identified as of black origin, as defined by the FDA Guidance on Collection of Race and Ethnicity Data in Clinical Trials, including those with more than one race, such as pardos. Cohort B will include (1) participants self-identified from Native Indigenous American origins and (2) participants self-identified from White origin who ethnically identify as Latinos, both as per the FDA guidance. The study will consist of five phases: Prescreening for biomarker evaluation, Screening, Treatment, Extension, and Follow-Up. Participants will be assessed during prescreening using the sponsor's required assays or previous results from CLIA-certified labs showing a pathogenic germline or somatic HRR alteration. The combination of niraparib/AA plus prednisone is FDA-approved for treating homologous repair deficient metastatic castration-resistant prostate cancer (HRD mCRPC). Given the benefits of this combination and the lack of representation in previous studies, a placebo-controlled study is deemed unethical. Thus, the study design includes two independent cohorts, both receiving the standard of care treatment. This study aims to provide additional information on the benefits of this therapy in underrepresented populations. Conducted with input from experts in racial inequities, the study results may be shared with participants through a plain language summary. Participants will be fully informed about the study's risks and requirements and will receive new information affecting their participation decision. Consent to participate is voluntary and can be withdrawn at any time without penalty. Written consent will be obtained following regulations and participant preferences.