Researchers of a recent study evaluated the efficacy and safety of osimertinib in patients with stage IV non-small-cell lung cancer who had uncommon EGFR mutations, specifically exon 18 G719X, exon 20 S768I, or exon 21 L861Q mutations. The results showed that osimertinib had an objective response rate of 47%, with patients experiencing partial response, stable disease, or progressive disease. The median progression-free survival was 10.5 months, and the median overall survival was 13.8 months. The most common adverse events included diarrhea, fatigue, anorexia, weight loss, and dyspnea. The trial demonstrated that osimertinib showed activity in patients with these uncommon EGFR mutations, suggesting its potential as a treatment option for this subgroup of patients.

Reference: Villaruz LC, Wang X, Bertino EM, et al. A single-arm, multicenter, phase II trial of osimertinib in patients with epidermal growth factor receptor exon 18 G719X, exon 20 S768I, or exon 21 L861Q mutations. ESMO Open. 2023;8(2):101183. doi: 10.1016/j.esmoop.2023.101183.