IMpower110: Interim overall survival (OS) analysis of a phase III study of atezolizumab (atezo) vs platinum-based chemotherapy (chemo) as first-line (1L) treatment (tx) in PD-L1–selected NSCLC

Abstract

Background: PD-L1/PD-1 inhibitors (CPI) as monotherapy or combined with platinum based doublet chemo (6 bevacizumab) are 1L tx options in metastatic NSCLC, with choice of agent(s) determined by PD-L1 expression. For patients (pts) who may be ineligible for combination therapy, CPI monotherapy remains an attractive tx choice. IMpower110 evaluated atezo as 1L tx in PD-L1-selected pts independent of tumour histology. Methods: IMpower110 enrolled 572 chemo-naive pts with stage IV nonsquamous (nsq) or squamous (sq) NSCLC, PD-L1 expression ! 1% on TC or IC, measurable disease by RECIST 1.1 and ECOG PS 0-1. Pts were randomised 1:1 to receive atezo 1200 mg IV q3w (Arm A) or platinum-based chemo (Arm B; 4 or 6 21-day cycles). Arm B nsq pts received cisplatin (cis) 75 mg/m 2 or carboplatin (carbo) AUC 6 þ pemetrexed 500 mg/m 2 IV q3w; Arm B sq pts received cis 75 mg/m 2 þ gemcitabine (gem) 1250 mg/m 2 or carbo AUC 5 þ gem 1000 mg/m 2 IV q3w. Stratification factors were sex, ECOG PS, histology and tumour PD-L1 status. The primary endpoint of OS is tested hierarchically in wild-type (WT; EGFR/ALK-negative) pts (TC3 or IC3 then TC2/3 or IC2/3 then TC1/2/3 or IC1/2/3). Results: The 3 primary efficacy populations included 554 TC1/2/3 or IC1/2/3 WT pts, 328 TC2/3 or IC2/3 WT pts and 205 TC3 or IC3 WT pts. In the TC3 or IC3 WT population , atezo monotherapy improved median OS by 7.1 mo (HR, 0.595; P ¼ 0.0106) vs chemo (Table); median follow-up was 15.7 mo. The safety population comprised 286 pts in Arm A and 263 pts in Arm B. Treatment-related AEs (TRAEs) and Grade 3-4 TRAEs occurred in 60.5% (Arm A) and 85.2% (Arm B), and 12.9% (Arm A) and 44.1% (Arm B), respectively.