Key Inclusion Criteria:

          -  Histologically or cytologically confirmed adenocarcinoma of the prostate without pure
             small cell carcinoma

          -  Metastatic, castration-resistant prostate cancer (mCRPC) with PSA value at screening

             ≥4 ng/mLthat has progressed within 6 months prior to screening as defined in the
             protocol

          -  Has received ≥2 lines prior systemic therapy approved in the metastatic and/or
             castration-resistant setting (in addition to androgen deprivation therapy [ADT])
             including at least one second-generation anti-androgen therapy (eg, abiraterone,
             enzalutamide, apalutamide, or darolutamide)

        Key Exclusion Criteria:

          -  Has received treatment with an approved systemic therapy within 3 weeks of dosing or
             has not yet recovered (ie, grade ≤1 or baseline) from any acute toxicities

          -  Has received any previous systemic biologic therapy within 5 half-lives of first dose
             of study therapy

          -  Has received prior PSMA-targeting therapy

          -  Dose Expansion Only: Has had prior anti-cancer immunotherapy

          -  Any condition that requires ongoing/continuous corticosteroid therapy (>10 mg
             prednisone/day or anti-inflammatory equivalent) within 1 week prior to the first dose
             of study therapy

          -  Ongoing or recent (within 5 years) evidence of significant autoimmune disease that
             required treatment with systemic immunosuppressive treatments

          -  Encephalitis, meningitis, neurodegenerative disease (with the exception of mild
             dementia that does not interfere with activities of daily living [ADLs]) or
             uncontrolled seizures in the year prior to first dose of study therapy

          -  Uncontrolled infection with human immunodeficiency virus (HIV), hepatitis B or
             hepatitis C infection; or diagnosis of immunodeficiency

        NOTE: Other protocol defined Inclusion/Exclusion Criteria apply