Cho JH, Lim SH, An HJ, et al. - Researchers sought to assess the efficacy and safety of osimertinib in patients with non–small-cell lung cancer (NSCLC) harboring uncommon epidermal growth factor receptor (EGFR) mutations via performing a multicenter, single-arm, open-label, phase II study in Korea. From March 2016 to October 2017, they included 37 patients (Median age: 60 years; 22 (61%) were male) who had histologically confirmed metastatic or recurrent NSCLC harboring EGFR mutations other than the exon 19 deletion, L858R and T790M mutations, and exon 20 insertion. Osimertinib was provided as first-line therapy to 61% of the patients. The identified mutations were G719X (n = 19; 53%), followed by L861Q (n = 9; 25%), S768I (n = 8; 22%), and others (n = 4; 11%). Objective response rate of 50% was reported (18 of 36 patients; 95% CI, 33% to 67%). Outcomes revealed favorable activity profile of osimertinib with manageable toxicity in patients with NSCLC harboring uncommon EGFR mutations.