TYK MEDICINES-B (02410) has announced that the New Drug Application (NDA) for its investigational Class 1 new drug, TY-9591 tablets (Edotinib Mesylate Tablets), has been accepted for review by the Center for Drug Evaluation (CDE) of the National Medical Products Administration (NMPA). TY-9591 tablets are a deuterated derivative of Osimertinib, offering high bioavailability and effective brain penetration. The NDA seeks approval for the first-line treatment of adult patients with locally advanced or metastatic non-small cell lung cancer (NSCLC) who have EGFR exon 19 deletion (19DEL) or exon 21 (L858R) substitution mutations, and who also have central nervous system (CNS) metastases. Data from Phase I (TYKM1601101) and Phase II (TYKM1601201) clinical studies have preliminarily demonstrated excellent intracranial and systemic response rates in NSCLC patients with brain metastases, indicating significant clinical benefits and addressing an unmet medical need. Furthermore, data from the key Phase II clinical study (TYKM1601202) confirmed its superior efficacy, showing better intracranial response rates and clinical benefits compared to Osimertinib. TY-9591 tablets hold substantial clinical value for treating EGFR-mutated lung cancer patients with brain metastases. As a deuterated compound of Osimertinib, TY-9591 tablets demonstrate clearer clinical value and advantages in terms of chemical structure, pharmacological effects, clinical efficacy and safety, and resistance mechanisms, offering significant improvements in disease prognosis.