Co-occurring EGFR p.E709X Mutation Mediates Primary Resistance to the Third-Generation EGFR-TKIs in EGFR p.G719X-Mutant Patients with Advanced NSCLC

Clin Cancer Res. 2024 Jun 14;30(12):2636-2646. doi: 10.1158/1078-0432.CCR-23-3302.

Abstract

Purpose: The current National Comprehensive Cancer Network (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 4,228 treatment-naïve patients with lung cancer who underwent targeted next-generation sequencing (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%), exerted a detrimental effect on outcomes in patients treated with third-generation EGFR-TKI [G719X/E709X vs. G719X; objective response rate (ORR): 0.00% vs. 47.62%, P < 0.001; mPFS: 7.18 vs. 14.2 months, P = 0.04, respectively]. Conversely, no significant difference was found in the treatment efficacy of afatinib between EGFR p.G719X/E709X and EGFR p.G719X patients (G719X/E709X vs. G719X; ORR: 71.43% vs. 56.67%, P = 0.99; mPFS: 14.7 vs. 15.8 months, P = 0.69, respectively). In vitro experiments elucidated a resistant drug sensitivity and poor inhibition of EGFR phosphorylation in Ba/F3 cells expressing EGFR p.G719A/E709K mutation upon the third-generation EGFR-TKI treatment.

Conclusions: Co-occurring EGFR p.E709X mutation mediated primary resistance to the third-generation EGFR-TKIs in EGFR p.G719X-mutant patients but remained sensitive to afatinib. A personalized treatment strategy should be undertaken based on the coexisting EGFR p.E709X mutation status.

Publication types

  • Multicenter Study

MeSH terms

  • Acrylamides / pharmacology
  • Acrylamides / therapeutic use
  • Adult
  • Afatinib / pharmacology
  • Afatinib / therapeutic use
  • Aged
  • Aged, 80 and over
  • Aniline Compounds / pharmacology
  • Aniline Compounds / therapeutic use
  • Carcinoma, Non-Small-Cell Lung* / drug therapy
  • Carcinoma, Non-Small-Cell Lung* / genetics
  • Carcinoma, Non-Small-Cell Lung* / pathology
  • Cell Line, Tumor
  • Drug Resistance, Neoplasm* / genetics
  • ErbB Receptors* / antagonists & inhibitors
  • ErbB Receptors* / genetics
  • Female
  • High-Throughput Nucleotide Sequencing
  • Humans
  • Lung Neoplasms* / drug therapy
  • Lung Neoplasms* / genetics
  • Lung Neoplasms* / pathology
  • Male
  • Middle Aged
  • Mutation*
  • Protein Kinase Inhibitors* / pharmacology
  • Protein Kinase Inhibitors* / therapeutic use
  • Retrospective Studies

Substances

  • ErbB Receptors
  • Protein Kinase Inhibitors
  • EGFR protein, human
  • Afatinib
  • Aniline Compounds
  • Acrylamides