Afatinib, an effective treatment for patient with lung squamous cell carcinoma harboring uncommon EGFR G719A and R776C co-mutations

Abstract

Background: Epidermal growth factor receptor (EGFR) is a crucial driven gene in non-small cell lung cancer (NSCLC), and the EGFR mutation rate in lung squamous cell carcinoma (SCC) is only 3 ~ 6.92%. Uncommon EGFR mutations, such as S768I, L861Q and G719X, accounting for approximately 15% of NSCLC harboring EGFR mutation. Afatinib, a second-generation EGFR-tyrosine kinase inhibitor (TKI), has been approved for NSCLC harboring uncommon mutations by the FDA in 2018. In our report, the lung SCC patient harboring uncommon compound EGFR mutation (G719A and R776C) benefited from afatinib.

Case presentation: A case of a lung SCC patient harboring uncommon compound EGFR mutation (G719A and R776C) benefited from afatinib, and new MYC amplification was detected by next-generation sequencing (NGS) after disease progression.

Conclusions: This case first identified a patient with lung squamous cell carcinoma harboring uncommon compound EGFR mutation (G719A and R776C) benefited from afatinib and achieved 11 months of progression-free survival (PFS). Then, new MYC amplification was detected after disease progression, indicating that MYC amplification may be one of the reasons for afatinib resistance.