A Study of Atezolizumab (Anti-PD-L1 Antibody) in Combination With Enzalutamide in Participants With Metastatic Castration-Resistant Prostrate Cancer (mCRPC) After Failure of an Androgen Synthesis Inhibitor And Failure of, Ineligibility For, or Refusal of a Taxane Regimen
Condition: Prostatic Neoplasms, Castration-Resistant
MeSH terms: Prostatic Neoplasms; Prostatic Neoplasms, Castration-Resistant
Intervention: Atezolizumab; Enzalutamide
Intervention description: Atezolizumab will be administered at a fixed dose of 1200 milligrams (mg), intravenous (IV) infusion on Day 1 of each 21-day cycle.; Enzalutamide capsules will be administered orally at a dose of 160 mg daily.
Intervention MeSH terms: Atezolizumab
Phase: Phase 3
Study type: Interventional
Primary purpose: Treatment
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Enrollment: 772.0
Sex: Male
Minimum age: 18 Years
Healthy volunteers: No

Summary:

      This Phase III, multicenter, randomized, open-label study will evaluate the safety and
      efficacy of atezolizumab (anti-programmed death-ligand 1 [anti-PD-L1] antibody) in
      combination with enzalutamide compared with enzalutamide alone in participants with mCRPC
      after failure of an androgen synthesis inhibitor (e.g., abiraterone) and failure of,
      ineligibility for, or refusal of a taxane regimen. Participants will be randomized to one of
      the two treatment arms (atezolizumab in combination with enzalutamide, and enzalutamide
      alone) in a 1:1 ratio (experimental to control arm) in global randomized phase. Participants
      will receive treatment until investigator-assessed confirmed radiographic disease progression
      per Prostate Cancer Working Group 3 (PCWG3) criteria or unacceptable toxicity.
    

Eligibility criteria:

        Inclusion Criteria:

          -  Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1

          -  Life expectancy greater than or equal to (>/=) 3 months

          -  Histologically confirmed adenocarcinoma of the prostate

          -  Known castrate-resistant disease with serum testosterone level less than or equal to
             (</=) 50 nanograms per deciliter (ng/dL) with prior surgical castration or ongoing
             androgen deprivation for the duration of the study

          -  Progressive disease prior to screening by PSA or imaging per PCWG3 criteria during or
             following the direct prior line of therapy in the setting of medical or surgical
             castration

          -  One prior regimen/line of a taxane-containing regimen for mCRPC or refusal or
             ineligibility of a taxane-containing regimen

          -  Progression on a prior regimen/line of an androgen synthesis inhibitor for prostate
             cancer

          -  Availability of a representative tumor specimen from a site not previously irradiated
             that is suitable for determination of programmed death-ligand 1 (PD-L1) status via
             central testing

          -  Adequate hematologic and end organ function

        Exclusion Criteria:

          -  Prior treatment with enzalutamide or any other newer hormonal androgen receptor
             inhibitor (e.g., apalutamide, ODM-201)

          -  Treatment with any approved anti-cancer therapy, including chemotherapy,
             immunotherapy, radiopharmaceutical or hormonal therapy (with the exception of
             abiraterone), within 4 weeks prior to initiation of study treatment

          -  Treatment with abiraterone within 2 weeks prior to study treatment

          -  Structurally unstable bone lesions suggesting impending fracture

          -  Known or suspected brain metastasis or active leptomeningeal disease

          -  Major surgical procedure other than for diagnosis within 4 weeks prior to initiation
             of study treatment or anticipation of need for a major surgical procedure during the
             course of the study

          -  Active or history of autoimmune disease or immune deficiency

          -  Prior allogeneic stem cell or solid organ transplantation

          -  History of idiopathic pulmonary fibrosis, organizing pneumonia (e.g., bronchiolitis
             obliterans), drug-induced pneumonitis, or idiopathic pneumonitis, or evidence of
             active pneumonitis on screening chest computed tomography (CT) scan

          -  Positive human immunodeficiency virus (HIV) test, active tuberculosis, active
             hepatitis B virus (HBV) or hepatitis C virus (HCV) infection

          -  Prior treatment with cluster of differentiation (CD)137 agonists or immune checkpoint
             blockade therapies, including anti Cytotoxic T Lymphocyte-Associated 4 (CTLA4),
             anti-programmed death 1 (PD-1), and anti-PD-L1 therapeutic antibodies

          -  Treatment with systemic immunostimulatory agents within 4 weeks or five half-lives of
             the drug, whichever is shorter, prior to initiation of study treatment

          -  Treatment with systemic immunosuppressive medication within 2 weeks prior to
             initiation of study

          -  History of seizure or any condition that may predispose to seizure within 12 months
             prior to study treatment, including history of unexplained loss of consciousness or
             transient ischemic attack