Icotinib, an effective treatment option for patients with lung adenocarcinoma harboring compound EGFR L858R and A871G mutation

Summary Compound epidermal growth factor receptor ( EGFR ) mutations are defined as double or multiple independent mutations of the EGFR tyrosine kinase domain (TKD), in which an EGFR -tyrosine kinase inhibitor (TKI)-sensitizing mutation is identified together with a mutation of unclarified clinical significance. Lung adenocarcinoma with compound EGFR mutation shows poor clinical response to EGFR -TKIs. Kobayashi et al. reported a non-small-cell lung cancer (NSCLC) patient whose tumor had EGFR exon21 L858R/A871G mutation presented rapid disease progression to erlotinib. However, in this case, we present an EGFR exon21 L858R/A871G mutation patient exerted significant benefit to icotinib, another first-generation EGFR -TKI, indicating that different EGFR -TKIs have diversiform sensitive sites and therapeutic effects, consistent mutation sites might achieve heterogeneous benefits from different EGFR -TKIs. Our case report provides promising EGFR -TKI for clinical treatment with EGFR exon21 L858R/A871G mutation in NSCLC. More dedicated efforts are needed to clarify their biologic effects on disease course and drug responsiveness.