Xenon's Azetukalner Slashes Seizure Frequency by Over 50% in Landmark Trial

Xenon Pharmaceuticals has announced positive results from its X-TOLE2 study of azetukalner in patients with focal onset seizures (FOS). The drug showed a significant reduction in seizure frequency, marking a key milestone for the company. Financial updates and ongoing clinical trials were also highlighted in its first-quarter 2026 report. The X-TOLE2 study met its primary goal, with patients on the 25 mg dose seeing a 53.2% median reduction in monthly FOS frequency. Those on the 15 mg dose experienced a 34.5% decrease, compared to placebo. The 25 mg group achieved a placebo-adjusted reduction of 42.7%, the highest efficacy recorded in a pivotal FOS trial, according to the company.

Enrollment continues in two other Phase 3 studies for azetukalner: X-TOLE3 for FOS and X-ACKT for primary generalised tonic-clonic seizures (PGTCS). The X-TOLE3 trial is expected to complete recruitment outside Japan by the end of 2026. Additionally, Phase 3 trials for azetukalner in major depressive disorder (MDD) and bipolar depression (BPD) are still accepting participants.

Beyond epilepsy, Xenon is advancing early-stage pain programmes targeting NaV1.7 and KV7. Phase 1 studies for these are set to wrap up in the second half of 2026. A separate NaV1.1 programme for epilepsy is also in development, with IND-enabling studies underway.

The company plans to submit a New Drug Application (NDA) for azetukalner in FOS to the U.S. FDA in the third quarter of 2026. Xenon will also present at three investor conferences during the second quarter of the year. The X-TOLE2 results position azetukalner as a promising treatment for focal onset seizures. With multiple Phase 3 trials progressing and an NDA submission planned, Xenon continues to expand its pipeline. The company’s focus remains on epilepsy, pain management, and mood disorders.