Update: Xenon Shares Fall on Pause in Enrollment for Depression Studies

06:54 AM EDT, 09/18/2026 (MT Newswires) -- (Updates with the latest share moves and details in the headline, first and second paragraph.) Xenon Pharmaceuticals (XENE) shares fell nearly 26% in premarket trading Friday after the company paused enrollment of new patients in studies for major depressive disorder and bipolar depression. The company said late Thursday it was voluntarily pausing enrollment after observing neuropsychiatric adverse events. The pause is expected to be temporary, and patients already enrolled will remain in the studies as the company evaluates potential dosing modifications. Separately, Xenon submitted a new drug application for azetukalner in focal seizures to the US Food and Drug Administration. The submission is based on positive clinical data from two global, randomized, double-blind, placebo-controlled trials, including the phase 2b X-TOLE and phase 3 X-TOLE2 studies. All four doses of azetukalner across the studies demonstrated a statistically significant reduction from baseline in monthly seizure frequency versus placebo. The drug was generally well tolerated, with a consistent safety profile, according to the company. Ongoing phase 3 X-TOLE3 and X-ACKT studies are enrolling patients with focal seizures and primary generalized tonic-clonic seizures, respectively, to support expansion across seizure types and global regions.