Key Inclusion Criteria:

          -  Men (> 18 years of age) with histologically or cytologically confirmed adenocarcinoma
             or poorly differentiated adenocarcinoma of the prostate without neuroendocrine
             differentiation with HRD deficiency by CTC-HRD assay and/or deleterious germline or
             somatic mutation in BRCA1 or BRCA2; mCRPC measurable disease and/or bone disease. •
             PSA progression with > 3 rising PSA levels with > 1 week between determinations and a
             screening PSA > 2 μg/L (2 ng/mL).

          -  Must be surgically or medically castrated with serum testosterone levels of < 1.73
             nmol/L (50 ng/dL), must have received > 1 prior androgen receptor-targeted therapy,
             and must have received > 1 taxane-based therapy.

          -  mCRPC with 1 or 2 of the following:

          -  Measurable disease per RECIST v1.1

          -  Bone disease

          -  CTC-HRD+ or BRCA1/2 mutation

          -  PSA progression (PCWG3 criteria)

          -  ≥1 androgen receptor-targeted therapy (eg, abiraterone acetate/prednisone or
             enzalutamide) for mCRPC with progressive disease

          -  ≥1 taxane for metastatic prostate cancer

          -  Prior sipuleucel-T and checkpoint inhibitors"

        Key Exclusion Criteria:

          -  Chemotherapy, hormonal therapy, biologic therapy, radionuclide therapy, immunotherapy,
             investigational agent, anticancer Chinese medicine, or herbal remedies ≤ 5 half-lives
             if the half-life is known, ≤ 14 days if not known, before start of study treatment

          -  Continued treatment with a bisphosphonate or denosumab is allowed, if administered at
             a stable dose > 28 days before start of study treatment

          -  Radiotherapy ≤ 21 days (≤ 14 days, if single fraction of radiotherapy) before start of
             study treatment

          -  Prior treatment for prostate cancer with any of the following:

               -  poly ADP ribose polymerase (PARP) inhibitor

               -  Platinum

               -  Cyclophosphamide

               -  Mitoxantrone

        NOTE: Other protocol defined Inclusion/Exclusion criteria may apply.