Impact of Lazertinib Dose Modification on Effectiveness and Safety

The primary objective is to evaluate Progression Free Survival (PFS) of the group (160 mg group) in which dose reduction was performed for 12 weeks after the first administration of Lazertinib. The Secondary objectives of this study are as follows. 1. To evaluate Progression-free survival (PFS) of the group maintaining the same dose (240mg group) and the group in which dose reduction was performed (160mg group) for 12 weeks after the first administration of Lazertinib 2. In the group maintaining the same dose (240mg group) and the group in which dose reduction was performed (160mg group) for 12 weeks after the first administration of Lazertinib, Time-to-Treatment Discontinuation(TTD), Objective Response Rate(ORR), Disease Control Rate(DCR), Tumor shrinkage and Overall Survival(OS) is evaluated. 3. In the group maintaining the same dose (240mg group) and the group in which dose reduction was performed (160mg group) for 12 weeks after the first administration of Lazertinib, specific reasons (adverse event name, grade, etc.) according to Lazertinib dose adjustment is evaluated. 4. To evaluate the treatment profile of Lazertinib including duration of treatment, dose adjustment, and reason for discontinuation of treatment. 5. To evaluate the safety of Lazertinib in the 240 mg and 160 mg groups

This study is a prospective multi-center observational study, and 11 institutions will participate to enroll 200 subjects competitively. We will evaluate the efficacy and safety of Lazertinib according to maintenance of the 240mg dose and reduction of the 160mg dose for 12 weeks after the first administration of Lazertinib in non-small cell lung cancer patients confirmed to be T790M mutation-positive after treatment failure with first- or second-generation EGFR-TKIs. The study period is up to 3 years from the date of IRB approval. Follow-up is 2 years from the last subject enrollment, and data will be collected through periodic medical record review during Lazertinib administration for enrolled subjects.