Xenon Pharmaceuticals Inc. has announced new data from its ongoing clinical development in epilepsy, including interim 48-month results from the X-TOLE open-label extension (OLE) study of azetukalner in patients with focal onset seizures. According to the company, participants treated for 48 months or longer experienced a monthly reduction in seizure frequency of 90.9%, with 38% achieving at least one year of seizure freedom. The new data suggest that long-term use of azetukalner may enable patients to attain and regain extended periods of seizure freedom, including in those with difficult-to-treat disease. These results, along with multiple real-world studies on the burden of depression and anti-seizure medication titration in epilepsy, are being presented at the American Epilepsy Society Annual Meeting (AES 2025), held from December 5-9, 2025, in Atlanta, Georgia. Additionally, new pre-clinical research in Dravet syndrome was presented, indicating potential for improved motor function through Na V 1.1 potentiation.