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

Conditions: Prostatic Neoplasms, Castration-Resistant

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