Positive response to Icotinib in metastatic lung adenocarcinoma with acquiring EGFR Leu792H mutation after AZD9291 treatment: a case report

BACKGROUND: Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) have been emerged as the standard selection in non-small cell lung cancer (NSCLC) patients with EGFR sensitive mutations. However, primary or acquired resistance to EGFR-TKIs seems inevitable, especially to third-generation TKIs, which has appeared absence of effective solutions so far. CASE PRESENTATION: Here we reported a NSCLC patient with EGFR sensitive mutation of deletion within EGFR exon 19, who had been resistant to icotinib and AZD9291 successively after a period of 18 months response duration. Next-generation sequencing (NGS) technique using plasma sample suggested an acquired EGFR Leu792H mutation, rather than C797S one. Interestingly, the patient obtained another 8 months of disease-free duration with symptoms greatly relieved after repeating icotinib administration. The overall survival of the patient has been thirty-six months and still in the extension. CONCLUSION: The presentation of the case may provide some selective therapeutic thoughts for NSCLC patients with acquired EGFR Leu792H mutation suffering resistance to the third-generation TKIs.