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Xenon Xenon Announces Azetukalner NDA Submission to FDA for Focal Seizures and Provides Update on Psychiatry Clinical Program September 17 , 2026 • New Drug Application for azetukalner in focal seizures submitted to U.S. Food and Drug Administration ; X - TOLE3 and X - ACKT continue to enroll focal seizure and PGTCS patients , respectively • Enrollment in X - NOVA2 study in MDD completed with approximately 360 total patients ; topline data readout expected Q1 2027 • The Company has voluntarily initiated a temporary pause of enrollment of new patients in ongoing psychiatry studies ; patients currently enrolled in the ongoing studies remain active • Conference call today at 4:30 pm ET VANCOUVER , BC and BOSTON , MA , Sept. 17 , 2026 ( GLOBE NEWSWIRE ) -- Xenon Pharmaceuticals Inc. ( Nasdaq : XENE ) , a neuroscience - focused biopharmaceutical company dedicated to drug discovery , clinical development , and commercialization of life - changing therapeutics for patients in need , today announced it has submitted a New Drug Application ( NDA ) for azetukalner in focal seizures ( FS ) to the U.S. Food and Drug Administration ( FDA ) . The NDA submission is based on positive clinical data from two global , randomized , double - blind , placebo - controlled trials for azetukalner in focal seizures , including the Phase 2b X - TOLE study and Phase 3 X - TOLE2 study . Across the two studies , treatment with all four doses of azetukalner demonstrated a statistically significant reduction from baseline in monthly seizure frequency compared with placebo , and azetukalner was generally well - tolerated with a consistent safety profile observed in both studies . These safety results are comparable with the long - term safety observed in the X - TOLE open label extension ( OLE ) study , with the entire epilepsy program generating more than 1,500 patient - years of safety and exposure data . " We are very pleased to announce completion of the NDA submission for azetukalner in focal seizures in epilepsy . Azetukalner has the potential to deliver much needed innovation to treat people living with focal seizures , with strong efficacy , a differentiated mechanism of action that may enable rational polytherapy , once - daily dosing with no dose adjustments for other antiseizure medications , and a consistent and generally well - tolerated safety profile , " said lan Mortimer , President and CEO of Xenon . " This is a significant milestone for Xenon as we continue to work toward the potential of our first approval and launch and becoming a fully integrated neuroscience company . " The ongoing Phase 3 X - TOLE3 and X - ACKT studies of azetukalner in focal seizures and primary generalized tonic - clonic seizures ( PGTCS ) , respectively , continue to enroll patients to support expansion of use across seizure types and global regions . In addition , the Company announced today that it has implemented a voluntary pause on enrollment for new patients in its ongoing clinical studies in major depressive disorder ( MDD ) and bipolar depression ( BPD ) , following an analysis of neuropsychiatric adverse events in these studies . Participants currently enrolled in the randomized controlled psychiatry studies and associated OLE studies will continue on study . The observed events , the rate of these events and their severity , are consistent with the known safety and tolerability profile of azetukalner and its mechanism ; however , such adverse events had not previously been seen in the Phase 2 X - NOVA clinical study in MDD . The enrollment pause is being implemented as a precautionary measure by Xenon in consultation with its Data Safety Monitoring Board ( DSMB ) and is expected to be temporary . Xenon is working to evaluate potential dosing modifications to help mitigate these adverse events . This voluntary action does not impact ongoing epilepsy studies . X - NOVA2 enrollment has reached approximately 80 % of its initial target of 450 patients , which is sufficiently powered to demonstrate a clinically meaningful change in the study's primary endpoint of HAM - D17 . The Company plans to complete the six - week dosing period for patients currently enrolled in the trial and unblind the data . Topline data for X - NOVA2 are now expected in Q1 2027 . " We remain very confident in the product profile of azetukalner as a potential new treatment option for patients with epilepsy based on strong efficacy and safety data and a consistent safety profile across over 1,500 patient - years of data , " said Chris Kenney , Chief Medical Officer of Xenon . " For potential expansion in psychiatry , we would like to evaluate whether modifying the dose regimen may help enhance azetukalner's tolerability profile in this indication . Completing the X - NOVA2 study will help assess the efficacy and tolerability of azetukalner in MDD , which will provide important data to guide us in the future clinical development in psychiatry indications . " Conference Call Information Xenon will host a conference call and webcast today at 4:30 pm Eastern Time ( 1:30 pm Pacific Time ) to discuss the azetukalner NDA submission and provide an update on the psychiatry clinical programs . A listen - only webcast can be accessed on the Investors section of the Xenon website , with a replay available following the event . Participants can access the conference call by