Clinical Trial of YH25448(Lazertinib) as the First-line Treatment in Patients With EGFR Mutation Positive Locally Advanced or Metastatic NSCLC (LASER301)

PFS was defined as the time from randomization until the date of objective progression or death(by any cause whichever comes first based on investigator assessment using RECIST v1.1 and was used to assess the efficacy of lazertinib compared to the gefitinib).

Time frame: At baseline and every 6 weeks for the first 18 months and then every 12 weeks relative to randomization until progression, assessed up to 29 months per participant.

Population: The full analysis set (FAS), FAS included all randomized participants.

To characterize the pharmacokinetics (PK) of lazertinib.

Time frame: A cerebrospinal fluid (CSF) sample once collected from participants with brain metastases, at Cycle 5 Day 1 or afterward.

The EORTC QLQ-C30 consists of 30 items and measures cancer participants' functioning (health related quality of life (HRQoL)) and symptoms for all cancer types. Questions can be grouped into 5 multi item functional scales (physical, role, emotional, cognitive, and social); 3 multi item symptom scales (fatigue, pain, nausea/vomiting); a 2 item global HRQoL scale; 5 single items assessing additional symptoms commonly reported by cancer participants (dyspnea, loss of appetite, insomnia, constipation, diarrhea) and 1 item on the financial impact of the disease. All of the scales and single-item measures range in score from 0 to 100. A high scale score represents a higher response level. * a high score for a functional scale represents a high / healthy level of functioning * a high score for the global health status / QoL represents a high QoL * but a high score for a symptom scale / item represents a high level of symptomatology / problems

Time frame: Questionnaires completed at Cycle 1 Day1 , Cycle2 Day 1 and then every 6 weeks relative to the randomization date until 28d safety f/u or progression f/u visit(whichever is later).

The EORTC QLQ-LC13 includes questions assessing cough, hemoptysis, dyspnea, site specific pain (symptoms), sore mouth, dysphagia, peripheral neuropathy, and alopecia (treatment related side effects), and pain medication. The items on both measures were scaled and scored using the recommended EORTC procedures. Raw scores were transformed to a linear scale ranging from 0 to 100, with a higher score representing a higher level of functioning or higher level of symptoms. Provided at least half of the items in the scale were completed, the scale score was calculated using only those items for which values existed.

Time frame: Questionnaires completed at Cycle 1 Day1 , Cycle2 Day 1 and then every 6 weeks relative to the randomization date until 28d safety f/u or progression f/u visit(whichever is later).

The EQ-5D comprises the following two questionnaires: * The EQ-5D comprises 5 dimensions of health (mobility, self-care, usual activities, pain/discomfort, anxiety/depression). Each dimension comprises five levels (no problems, slight problems, moderate problem, severe problem, unable/extreme problems). * The EQ VAS records the participants self-rated health status on a vertical graduated (0-100) visual analogue scale. The patient's self-rated health is assessed on a scale from 0 (worst imaginable health state) to 100 (best imaginable health state) by the EQ-VAS.

Time frame: Questionnaires completed at Cycle 1 Day1 , Cycle2 Day 1 and then every 6 weeks relative to the randomization date until 28d safety f/u or progression f/u visit(whichever is later).

The depth of response was defined as the best percent change in the sum of diameters of target lesions in the absense of new lesions or progression of non-target lesions compared to the baseline and was used to further assess the efficacy of lazertinib compared with gefitinib.

Time frame: At baseline and every 6 weeks for the first 18 months and then every 12 weeks relative to randomization until progression.

DCR was defined as the percentage of participants who have a best overall response of CR or PR or SD(SD at \>= 6weeks prior to any PD event) and was used to further assess the efficacy of lazertinib compared with gefitinib.

Time frame: At baseline and every 6 weeks for the first 18 months and then every 12 weeks relative to randomization until progression, assessed up to 29 months per participant.

Population: The full analysis set (FAS), FAS included all randomized participants.

DoR was defined as the time from the date of first documented response(CR or PR) until the date of documented progression or death, whichever comes first and was used to further assess the efficacy of lazertinib compared with gefitinib.

Time frame: At baseline and every 6 weeks for the first 18 months and then every 12 weeks relative to randomization until progression, assessed up to 29 months per participant.

Population: The full analysis set (FAS), FAS included all randomized participants.

ORR was defined as the percentage of participants with measurable disease with at least on visit response of complete response(CR) or Partial response(PR) and it was used to further assess the efficacy of lazertinib compared with gefitinib.

Time frame: At baseline and every 6 weeks for the first 18 months and then every 12 weeks relative to randomization until progression, assessed up to 29 months per participant.

Population: The full analysis set (FAS), FAS included all randomized participants.

OS was defined as the time from the date of randomization until the date of death due to any cause and was used to further assess the efficacy of lazertinib compared with gefitinib.

Time frame: From the randomization to end of study or date of death from any cause, whichever comes first, assessed every 6 weeks. (Up to 29 months per participant.)

Population: The full analysis set (FAS), FAS included all randomized participants.

To characterize the pharmacokinetics (PK) of lazertinib.

Time frame: Blood samples collected from each participant at pre-dose, 1 to 3 hours, and 4 to 6 hours post-dose on Day 1 Cycle 1, Day 1 Cycle 2, Day 1 Cycle 5, Day 1 Cycle 9, and Day 1 Cycle 13.

Time to Response was defined as the time from the date of randomization until the date of first documented response and was used to further assess the efficacy of lazertinib compared with gefitinib.

Time frame: At baseline and every 6 weeks for the first 18 months and then every 12 weeks relative to randomization until progression.