Updated Overall Survival Analysis From IMpower110: Atezolizumab Versus Platinum-Based Chemotherapy in Treatment-Naive Programmed Death-Ligand 1-Selected NSCLC.

Introduction: IMpower110 previously revealed significant overall survival (OS) benefit with atezolizumab versus chemotherapy in patients with treatment-naive EGFR- and ALK-negative (wild type [WT]) metastatic NSCLC with high programmed death-ligand 1 (PD-L1) expression (≥50% on tumor cells [TCs] or ≥10% on tumor-infiltrating immune cells [ICs], per SP142 immunohistochemistry assay; p = 0.0106). We present primary OS analyses in lower PD-L1 expression groups and an updated, exploratory analysis in the high PD-L1 expression group.

Methods: This open-label, phase 3 trial randomized patients with PD-L1 expression on greater than or equal to 1% of TC or IC to receive atezolizumab or platinum-based chemotherapy. The primary end point was OS, hierarchically tested in PD-L1 expression WT subgroups: first the high PD-L1 expression subgroup, then the high-or-intermediate PD-L1 expression subgroup (≥5% on TC or IC), and then the any PD-L1 expression subgroup (≥1% on TC or IC).

Results: The any PD-L1 expression WT population included 554 patients (excluded 18 EGFR- or ALK-positive patients). With 17 months' additional follow-up, OS improvement in the atezolizumab versus chemotherapy arm was not statistically significant in high-or-intermediate PD-L1 expression WT patients (n = 328; hazard ratio = 0.87, 95% confidence interval: 0.66-1.14, p = 0.3091; median = 19.9 versus 16.1 mo), precluding formal OS testing in any PD-L1 expression WT patients. Exploratory analysis in high PD-L1 expression WT patients (n = 205) revealed maintained OS benefit in the atezolizumab arm (hazard ratio = 0.76, 95% confidence interval: 0.54-1.09; median = 20.2 versus 14.7 mo). Updated safety data continued to favor atezolizumab.

Conclusions: Statistical significance for OS was not revealed in the high-or-intermediate expression WT group, and, as a result, OS in the any PD-L1 expression WT group was not formally tested. No new safety signals were found. This updated analysis of IMpower110 supports using atezolizumab in treatment-naive, metastatic WT NSCLC with high PD-L1 expression.