Phase II Trial of Atezolizumab As First-Line or Subsequent Therapy for Patients With Programmed Death-Ligand 1–Selected Advanced Non–Small-Cell Lung Cancer (BIRCH)

PurposeBIRCH was designed to examine the efficacy of atezolizumab, a humanized anti–programmed death-ligand 1 (PD-L1) monoclonal antibody, in advanced non–small-cell lung cancer (NSCLC) across lines of therapy. Patients were selected on the basis of PD-L1 expression on tumor cells (TC) or tumor-infiltrating immune cells (IC).Patients and MethodsEligible patients had advanced-stage NSCLC, no CNS metastases, and zero to two or more lines of prior chemotherapy. Patients whose tumors expressed PD-L1 using the SP142 immunohistochemistry assay on ≥ 5% of TC or IC (TC2/3 or IC2/3 [TC or IC ≥ 5% PD-L1–expressing cells, respectively]) were enrolled. Atezolizumab 1,200 mg was administered intravenously every 3 weeks. Efficacy-evaluable patients (N = 659) comprised three cohorts: first line (cohort 1; n = 139); second line (cohort 2; n = 268); and third line or higher (cohort 3; n = 252). The primary end point was independent review facility–assessed objective response rate (ORR; Response Evaluation Criteria in Soli...