Treatments and/or Procedures

Study Criteria

Inclusion Criteria:

  -  Histologic confirmation of adenocarcinoma of the prostate without small cell features

  -  Current evidence of metastatic disease documented by either bone lesions on
     radionuclide bone scan and/or soft tissue lesions on computerized tomography/magnetic
     resonance imaging (CT/MRI)

  -  Eastern Cooperative Oncology Group (ECOG) performance status 0-1

  -  Ongoing androgen deprivation therapy (ADT) with a gonadotropin-releasing hormone
     (GnRH) analogue or bilateral orchiectomy

  -  Documented prostate cancer progression per Prostate Cancer Working Group (PCWG3)
     criteria within 6 months prior to screening

  -  Chemotherapy-naïve for metastatic castration-resistant prostate cancer (mCRPC), with 1
     to 2 prior second generation hormonal therapies in the recurrent non-metastatic
     setting and/or metastatic setting, and no more than 1 second generation hormonal
     therapy in the mCRPC setting. Must have progressed during or after second generation
     hormonal therapy or have documented intolerance to second generation hormonal therapy

  -  Participants must meet one of the following criteria regarding tissue submission:
     Sufficient tumor samples from a newly obtained ("fresh") biopsy (obtained during
     screening); or archival tumor tissue in the form of formalin-fixed paraffin-embedded
     (FFPE) block or unstained tumor tissue slides. For participants with bone-only disease
     or inaccessible soft tissue lesions or if the biopsy procedure would pose an
     unacceptable clinical risk for the participant, submission of tumor tissue obtained
     from a fresh biopsy is not required.

  -  Men must agree to follow specific methods of contraception, if applicable

Exclusion Criteria:

  -  Active brain metastases

  -  Active, known, or suspected autoimmune disease

  -  Condition requiring systemic treatment with corticosteroids (> 10 mg daily prednisone
     equivalent) or other immunosuppressive medications within 14 days of start of study
     treatment. Inhaled or topical steroids or adrenal replacement steroid doses are
     permitted in the absence of active autoimmune disease

  -  Prior treatment with an anti-PD-1, anti-PD-L1, anti-PD-L2, anti-CTLA-4 antibody, or
     any other antibody or drug specifically targeting T-cell co-stimulation or checkpoint
     pathways

  -  Prior treatment with docetaxel or other chemotherapy for mCRPC. Prior docetaxel for
     metastatic castration-sensitive prostate cancer is permitted if at least 12 months
     have elapsed from last dose of docetaxel

Other protocol-defined inclusion/exclusion criteria apply