TYK MEDICINES-B (02410) announced that the interim analysis results from the pivotal Phase II ESAONA study for its self-developed drug, TY-9591 (mesylate edotinib tablets), versus osimertinib in the first-line treatment of EGFR-mutant non-small cell lung cancer (NSCLC) patients with brain metastases, were presented as a late-breaking abstract "LBA" oral report at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting. While EGFR tyrosine kinase inhibitors (TKIs) have significantly improved survival for NSCLC patients with sensitive EGFR mutations, their efficacy remains limited for those with brain metastases, which severely threaten life, health, and quality of life. TY-9591 is a novel third-generation EGFR-TKI that demonstrated favorable intracranial efficacy and safety in two earlier clinical studies (NCT04204473, NCT05146219). The ESAONA study is an open-label, multicenter, randomized controlled pivotal Phase II clinical trial designed to evaluate the efficacy and safety of edotinib compared to osimertinib as a first-line treatment for EGFR classical mutation NSCLC patients with brain metastases. Enrolled patients were randomized in a 1:1 ratio to either the edotinib group (160mg QD) or the osimertinib group (80mg QD), stratified by EGFR mutation subtype (19Del or L858R) and the number of intracranial lesions (>3 or ≤3). The primary endpoints of the study include intracranial objective response rate (iORR) and intracranial progression-free survival (iPFS) as assessed by blinded independent central review (BICR) per RECIST v1.1 criteria. Secondary endpoints include iORR and iPFS assessed by investigators (INV) per RECIST v1.1 and RANO-BM criteria, as well as ORR, PFS, intracranial duration of response (iDoR), overall survival (OS), and safety evaluated by both BICR and INV. As of the data analysis cutoff date of December 15, 2025, the median follow-up time in the study was 19.12 months. A total of 224 patients were enrolled (111 in the edotinib group, 113 in the osimertinib group), with balanced and comparable baseline characteristics between the two groups.