Osimertinib, an irreversible, orally administered EGFR-TKI, was initially approved by the FDA in 2015 and was intended for use only as an adjuvant therapy after tumor resection in adult NSCLC patients with EGFR exon 19 deletions or exon 21 L858 mutations. Here, EGFR is linked to non-small cell lung carcinoma.