Because of its promising performance in clinical trials, osimertinib has been approved to treat NSCLC patients with EGFR activating mutations (e.g., exon 19 deletion and exon 21 point mutation L858R) as a frontline therapy or those progressed from 1st or 2nd generation EGFR-TKIs due to EGFR T790M mutation as a second-line treatment option [2, 3]. The gene discussed is EGFR; the disease is non-small cell lung carcinoma.