Poziotinib treatment in intractable NSCLC: Epidermal growth factor receptor and human epidermal growth factor receptor 2 exon 20 insertion mutation disease

Nearly 4% of all patients with non-small-cell lung cancer (NSCLC) harbour epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2) exon 20 mutations, lacking efficient response to pan-HER tyrosine kinase inhibitors (TKIs) (afatinib, lapatinib, neratinib or dacomitinib). Exon 20 of EGFR and HER2 contains two major regions, the α-C helix (residues 762–766 in EGFR and 770–774 in HER2) and the loop after the α-C helix (residues 767–774 in EGFR and 775–783 in HER2).