Lazertinib Versus Gefitinib Tyrosine Kinase Inhibitors in Treatment-Naíve Patients With EGFR-Mutated Advanced NSCLC: Analysis of the Asian Subpopulation in LASER301

Introduction: Lazertinib is a third-generation central nervous system–penetrant tyrosine kinase inhibitor targeting mutant EGFR in NSCLC. Lazertinib exhibited improved efficacy versus gefitinib in the LASER301 study; this subset analysis compared lazertinib with gefitinib among Asian patients. Methods: The phase 3 LASER301 study evaluated lazertinib efficacy and safety in treatment-naive patients with EGFR-mutated (exon 19 deletion or L858R) locally advanced or metastatic NSCLC. Patients were randomized one-to-one and received either lazertinib or gefitinib. The primary end point was investigator-assessed progression-free survival using Response Evaluation Criteria in Solid Tumors version 1.1. Secondary end points included overall survival, objective response rate, duration of response, and safety. Results: Between February 13, 2020, and July 29, 2022, among 258 patients of Asian descent, the median progression-free survival was significantly longer with lazertinib than gefitinib (20.6 versus 9.7 mo; hazard ratio: 0.46; 95% confidence interval [CI]: 0.34–0.63, p < 0.001), and the benefit was consistent across predefined subgroups (exon 19 deletion, L858R, baseline central nervous system metastases). Objective response rate and disease control rates were similar between treatment groups. The median duration of response was 19.4 months (95% CI: 16.6–24.9) versus 9.6 months (95% CI: 6.9–12.4) in the lazertinib versus gefitinib group. Adverse event rates in Asian patients were comparable with the overall LASER301 population. Adverse events leading to discontinuation in the lazertinib and gefitinib groups were 13% and 12%, respectively. Conclusions: In LASER301, efficacy and safety results in Asian patients were consistent with the overall population. Lazertinib exhibited better efficacy than gefitinib in Asian patients with a tolerable safety profile.