Real-world clinical evidence of lazertinib use in acquired EGFR T790M mutated non-small cell lung cancer

Background: Lazertinib is a third generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) designed to overcome EGFR T790M mutation. Currently, lazertinib is approved for usage in the acquired EGFR T790M mutation population based on promising clinical and safety profiles. In this study, we evaluated the clinical outcomes of lazertinib in acquired EGFR T790M mutated non-small cell lung cancer (NSCLC) patients in a real-world clinical setting.Methods: Clinical outcomes of 103 patients treated with lazertinib, from July 2021 to August 2022, for NSCLC with acquired EGFR T790M mutation were retrospectively analyzed. EGFR T790M mutation was confirmed using either a cell-free EGFR test (48.5%) or a tissue-based test (51.5%).Results: The median follow-up duration was 11.4 months (95% CI: 10.4-13.1), and 58.3% of patients remained on treatment at the time point of data analysis. The objective response rate was 72.8%. The median progression-free survival (PFS) was not reached, and the PFS rates at 6 and 12 months were 81.7% and 65.1%, respectively. The median PFS in a subgroup treated with lazertinib based on T790M-positive tissue was significantly longer than that in a subgroup treated based on T790M-positive plasma (not reached vs. 14.5 months) (hazard ratio, 0.43; 95% confidence interval, 0.21-0.87). Related to adverse events, there was no treatment-related mortality. However, the lazertinib dose was adjusted in 39 patients (37.9%), including 10 patients (9.7%) with permanent discontinuation. Peripheral sensory-motor related adverse events were observed in 65 patients (63.1%) (paresthesia: n=58; muscle cramping: n=24), leading to dose reduction and permanent discontinuation in 17 (16.5%) and 5 (4.9%) patients, respectively. There was no difference in PFS between the groups with and without dose-adjustment (P=0.40).Conclusions: Our result demonstrates the real-world clinical efficacy of lazertinib in acquired EGFR T790M mutation. Although dose reduction due to adverse events was not uncommon, it did not impair clinical efficacy of lazertinib.