In the mouse model of EGFR-mutated NSCLC, osimertinib had antitumor activity in tumours driven by EGFRL858R mutation comparable to that of afatinib, but it was more effective than afatinib in EGFR double mutants, L858R/T790M or exon 19 del/T790M EGFR [125,148]. This evidence concerns the gene EGFR and non-small cell lung carcinoma.