Inclusion Criteria:

   - Men with histologically or cytologically confirmed adenocarcinoma of the prostate

   - Prior treatment with one, and only one, NHT (eg, abiraterone, apalutamide,
   darolutamide, or enzalutamide) for castration-sensitive locally advanced (T3 or T4) or
   mCSPC, M0 CRPC, or mCRPC

   - Surgical or medical castration, with serum testosterone ≤ 50 ng/dL (≤ 1.73 nmol/L) at
   screening

   - Measurable (extrapelvic soft tissue) metastatic disease per Investigator assessment
   defined by at least one of the following: measurable visceral disease (eg, adrenal,
   kidney, liver, lung, pancreas, spleen) per RECIST 1.1; OR measurable extrapelvic
   adenopathy (ie, adenopathy above the aortic bifurcation)

   - Progressive disease at study entry as defined by specific criteria for prostate
   specific antigen (PSA) progression OR soft tissue disease progression in the opinion
   of the Investigator (Note: subjects with bone disease progression alone are not
   eligible)

   - Age ≥ 18 years old or meeting country definition of adult, whichever is older, on the
   day of consent

   - ECOG performance status of 0 or 1

   - Recovery to baseline or ≤ Grade 1 per Common Terminology Criteria for Adverse Events
   (CTCAE) v5 from toxicities related to any prior treatments, unless AE(s) are
   clinically nonsignificant and/or stable on supportive therapy in the opinion of the
   Investigator

   - Adequate organ and marrow function based upon specific laboratory assessments obtained
   within 21 days prior to randomization

   - Understanding and ability to comply with protocol requirements

Exclusion Criteria:

   - Any prior nonhormonal therapy initiated for the treatment of mCRPC

   - Receipt of abiraterone within 1 week; cyproterone within 10 days; or flutamide,
   nilutamide, bicalutamide, enzalutamide, or other androgen-receptor inhibitors within 2
   weeks before randomization

   - Radiation therapy within 4 weeks (2 weeks for bone metastases) prior to randomization
   (subjects with clinically relevant ongoing complications from prior radiation therapy
   are not eligible)

   - Known brain metastases or cranial epidural disease unless adequately treated and
   clinically stable at least 4 weeks prior to randomization

   - Symptomatic or impending spinal cord compression or cauda equina syndrome

   - Concomitant anticoagulation with oral anticoagulants (some specific exceptions apply)

   - Administration of a live, attenuated vaccine within 30 days prior to randomization

   - Systematic treatment with, or any condition requiring, either corticosteroids (>10 mg
   daily prednisone equivalent) or other immunosuppressive medications within 14 days
   prior to randomization

   - Uncontrolled, significant intercurrent or recent illness

   - Major surgery within 4 weeks prior to randomization

   - Corrected QT interval calculated by the Fridericia formula (QTcF) > 480 ms per ECG
   within 21 days before randomization

   - Inability or unwillingness to swallow pills or receive IV administration

   - Previously identified allergy or hypersensitivity to components of the study treatment
   formulations or history of severe infusion-related reactions to monoclonal antibodies

   - Any other active malignancy at time of randomization or diagnosis of another
   malignancy within 2 years prior to randomization that requires active treatment (some
   exceptions apply such as locally curable cancers that have apparently been cured).