Osimertinib is an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) that binds to certain mutant forms of EGFR (T790M, L858R, and exon 19 deletion) that predominate in non-small cell lung cancer (NSCLC) tumours following treatment with first-line EGFR-TKIs². It exhibits a nine-fold greater affinity for select EGFR-sensitizing and T790M-resistance mutations than to wild-type EGFR¹.