Co-occurring EGFR p.E709X mutation Mediates Primary Resistance to the Third-generation EGFR-TKIs in EGFR p.G719X-mutant Patients with Advanced NSCLC
Abstract. Purpose: Current NCCN guidelines recommend afatinib or osimertinib as the preferred first-line treatment strategy for patients with advanced NSCLC harboring EGFR p.G719X mutation. However, in the absence of head-to-head trials comparing afatinib with osimertinib in EGFR p.G719X mutant patients, it is unclear which regimen is the preferred treatment option. Experimental Design: A large cohort of 4228 treatment-naïve patients with lung cancer who underwent targeted NGS testing was screened for EGFR p.G719X mutation. A multicenter cohort involving 68 EGFR p.G719X-mutant patients with advanced NSCLC and NGS profiling was retrospectively enrolled to evaluate clinical responses to afatinib(n=37) and the third-generation EGFR-TKIs(n=31). Ba/F3 cells stably expressing the EGFR p.G719A mutation were created to investigate the response to EGFR-TKIs in vitro. Results: Concurrent EGFR p.E709X mutations, being the most frequent co-occurring EGFR mutation in EGFR p.G719X-mutant NSCLC(~30%)