Final Analysis Data and Exploratory Biomarker Analysis of a Randomized Phase 2 Study of Osimertinib Plus Bevacizumab Versus Osimertinib Monotherapy for Untreated Patients With Nonsquamous NSCLC Harboring EGFR Mutations: The WJOG9717L Study

Introduction: EGFR tyrosine kinase inhibitors have been the standard treatment for patients with NSCLC who have sensitive EGFR mutations. This study revealed final analysis survival data, biomarkers, and resistance mechanisms of osimertinib plus bevacizumab or osimertinib monotherapy in previously untreated patients with advanced EGFR-positive nonsquamous NSCLC.

Methods: We previously reported the primary results of a randomized, open-label, phase 2 study comparing osimertinib plus bevacizumab with osimertinib monotherapy for this population. In this exploratory analysis using tissue and plasma samples, we evaluated gene profiles at baseline and disease progression or the last dose using targeted deep sequencing.

Results: The median progression-free survival (PFS) by the blinded independent central reviewer was 22.1 months for the osimertinib plus bevacizumab arm and 20.2 months for the osimertinib arm (hazard ratio [HR] = 0.864, 95% confidence interval [CI]: 0.549-1.359). The 3-year overall survival was not different between the two arms (osimertinib plus bevacizumab: 57.1%; osimertinib monotherapy: 65.0%; HR 1.271, 95% CI: 0.727-2.223). A total of 94 patients had assessable plasma samples at baseline, and 40 had assessable pretreatment tissue samples. EGFR mutations (76.6%) and TP53 mutations (44.7%) were detected in plasma samples at baseline. In patients with plasma TP53 mutations (n = 42), the median PFS by blinded independent central reviewer was 19.8 months for the osimertinib plus bevacizumab arm and 20.2 months for the osimertinib arm (HR = 1.107, 95% CI: 0.534-2.297).

Conclusions: There was also no significant difference in the PFS between the two arms, even in patients with TP53 mutations.