After gaining positive topline data from its phase 3 trial, Xenon Pharmaceuticals is preparing to submit a New Drug Application to the FDA in Q3 2026 for its oral drug, azetukalner, to treat focal onset seizures (FOS).
Azetukalner is a novel, potent, Kv7 potassium channel opener in clinical development for epilepsy, major depressive disorder (MDD), and bipolar depression (BPD). It works by opening potassium channels in the nervous system to prevent excessive neuronal firing, which is a major contributor of epilepsy, MDD, BPD, and similar disorders. If approved, azetukalner would be the only KV7 potassium channel opener available for the treatment of epilepsy.
In the X-TOLE2 study, a 25 mg dose led to a -53.2% median percent change (MPC) from baseline to week 12 in monthly FOS frequency and a 15 mg dose to -34.5%, whereas the placebo only led to a change of -10.4%. The 25 mg dose group outperformed the phase 2b X-TOLE study, while the placebo-adjusted MPC over eight weeks was -34.6%. The safety and tolerability profile in the phase 3 study was similar previous clinical trials.