IMpower150 Final Exploratory Analyses for Atezolizumab Plus Bevacizumab and Chemotherapy in Key NSCLC Patient Subgroups With EGFR Mutations or Metastases in the Liver or Brain

Abstract

Introduction: Final overall survival (OS) analyses are presented for EGFR mutations and liver or brain metastases subgroups in the phase 3 IMpower150 study (NCT02366143) evaluating atezolizumab plus bevacizumab plus carboplatin and paclitaxel (ABCP) or atezolizumab plus carboplatin and paclitaxel (ACP) versus bevacizumab plus carboplatin and paclitaxel (BCP).

Methods: Overall, 1202 patients (intention-to-treat population) with chemotherapy-naive, metastatic, nonsquamous NSCLC were randomized to ABCP, ACP, or BCP. Patients with treated, stable brain metastases were permitted. OS was evaluated in EGFR mutations and baseline liver metastases subgroups; rate and time to development of new brain metastases were evaluated in the intention-to-treat patients.

Results: At data cutoff (September 13, 2019; median follow-up, 39.3 mo), OS improvements were sustained with ABCP versus BCP in sensitizing EGFR mutations (all: hazard ratio [HR] = 0.60; 95% confidence interval [CI]: 0.31-1.14; previous tyrosine kinase inhibitor [TKI]: HR = 0.74; 95% CI: 0.38-1.46) and baseline liver metastases (HR = 0.68; 95% CI: 0.45-1.02) subgroups. ACP did not have survival benefit versus BCP in sensitizing EGFR mutations (all: HR = 1.0; 95% CI: 0.57-1.74; previous TKI: HR = 1.22; 95% CI: 0.68-2.22) or liver metastases (HR = 1.01; 95% CI: 0.68-1.51) subgroups. Overall, 100 patients (8.3%) developed new brain metastases. Although not formally evaluated, an improvement toward delayed time to development was found with ABCP versus BCP (HR = 0.68; 95% CI: 0.39-1.19).

Conclusions: This final exploratory analysis revealed OS benefits for ABCP versus BCP in patients with sensitizing EGFR mutations, including those with previous TKI failures, and with liver metastases, although these results should be interpreted with caution. The impact of ABCP on delaying the development of new brain lesions requires further investigation.

Keywords: Atezolizumab; Bevacizumab; EGFR mutation; IMpower150; Nonsquamous NSCLC.