A new once-daily pill has demonstrated a significant reduction in seizures for adults with hard-to-treat focal epilepsy, according to pivotal Phase III results presented at the American Academy of Neurology meeting. The drug, azetukalner, could become the first in its class approved for epilepsy if regulators grant approval later this year.
The X-TOLE2 study involved 374 adults with focal onset seizures who had not achieved control with a median of five prior anti-seizure medications. Participants were given either a 15mg dose, a 25mg dose, or a placebo. After 12 weeks, the higher dose group saw a median 53.2% reduction in monthly seizure frequency, while the lower dose achieved a 34.5% reduction. This compared to a 10.4% reduction in the placebo group. The trial focused on a highly treatment-resistant population, with participants experiencing over 12 seizures per month on average at the study's start.
Azetukalner works by a novel mechanism, acting as a potent KV7 potassium channel opener. It is designed to calm overactive neurons in the brain by facilitating the flow of potassium ions, thereby reducing the excessive electrical firing that causes seizures. Its developers highlight the convenience of a once-daily oral dose that requires no titration. The safety and tolerability profile was reported as consistent with earlier studies.
Navigating a Crowded Market and Historical Concerns
The path to market, however, presents challenges. The focal epilepsy treatment landscape is crowded with established medications. Furthermore, azetukalner belongs to the same drug class as ezogabine (Potiga), a therapy withdrawn from the market in 2017 due to safety concerns. Analysts note that Xenon Pharmaceuticals will need to clearly differentiate its drug's safety profile from that predecessor to gain trust from clinicians and regulators.
Despite these hurdles, the strong efficacy data in a refractory patient population addresses a clear unmet need. The company has indicated it plans to submit a New Drug Application to the U.S. Food and Drug Administration in the third quarter of 2026. If approved, azetukalner would be the first KV7 potassium channel opener available for epilepsy, offering a new option for patients whose seizures are not controlled by current therapies.