Lazertinib and Chemotherapy Combination in EGFR-mutant NSCLC Patients Without ctDNA Clearance After lead-in Lazertinib Monotherapy

Lazertinib is an oral third-generation irreversible tyrosine kinase inhibitor (TKI) that has proved to selectively inhibit EGFR-TKI sensitizing mutations (exon 19 deletion or exon 21 L858R) and be effective in patients with central nervous system (CNS) metastases. However, all patients eventually experience disease progression. For patients with MRD, lazertinib plus cytotoxic anticancer drug can prolong the duration of response or even induce complete cure, indicating this combined treatment strategy is considered the safest and most effective. The objective of this phase 2 prospective two-arm clinical trial is to evaluate the safety and efficacy of lazertinib alone or in combination with cytotoxic chemotherapy in EGFR-mutant (exon 19 deletion or exon 21 L858R) NSCLC patients without ctDNA clearance after lead-in lazertinib. If anticancer drugs are used only for patients with MRD, the risk of resistance development will decrease, improving PFS. Hypothesis: to evaluate the efficacy defined as the PFS rate of lazertinib alone or in combination with a cytotoxic anticancer drug in EGFR-mutant NSCLC patients without ctDNA clearance after lead-in lazertinib monotherapy.