XEN1101, A Differentiated KV7 Potassium Channel Modulator for the Treatment of Epilepsy

We are developing XEN1101, a differentiated Kv7 potassium channel modulator, for the treatment of epilepsy and potentially other neurological disorders.

The Kv7 potassium channel mechanism has been clinically validated with ezogabine, an earlier generation Kv7 modulator that was approved by the FDA as an adjunctive treatment for adults with focal seizures with or without secondary generalization. XEN1101’s unique composition is chemically designed to improve upon potency, selectivity and pharmacokinetics, or PK, of ezogabine, and is not expected to have ezogabine’s composition-specific tissue pigmentation effects.

Clinical Development

Based on the encouraging Phase 1 and Phase 1b TMS data, we have initiated a Phase 2b clinical trial with XEN1101. Designed as a randomized, double-blind, placebo-controlled, multicenter study, a Phase 2b clinical trial (called the X-TOLE study) is ongoing to evaluate the clinical efficacy, safety, and tolerability of XEN1101 administered as adjunctive treatment in approximately 300 adult patients with focal epilepsy. The primary endpoint is the median percent change in monthly focal seizure frequency from baseline compared to treatment period of active versus placebo. Xenon is in close collaboration with each of the XEN1101 clinical sites in North America and Europe, taking specific direction from their respective clinical guidelines as they relate to new patient screening and randomization in the context of the COVID-19 pandemic. Xenon is expanding the X-TOLE clinical trial to include new sites in both existing and new jurisdictions to support increased patient screening. It is anticipated that patient randomization will be completed in the first half of 2021, with topline data anticipated in the third quarter of 2021, dependent upon ongoing patient enrollment rates. In addition, Xenon expects to support the initiation of a Phase 2 proof-of-concept clinical trial examining XEN1101 in a non-epilepsy indication within the first half of 2021.

Phase 1
Phase 2
Phase 3


for Epilepsy

About Focal Seizures

A focal seizure is localized within the brain and can either stay localized or spread to the entire brain, which is typically categorized as a secondary generalized seizure. Focal seizures are the most common type of seizure experienced by people with epilepsy. The treatment of an individual patient with focal seizures is currently focused on reduction of seizure frequency, with seizure freedom as the ultimate goal. Focal seizures (simple, complex and secondary generalized tonic-clonic) account for approximately 60% of seizures (GlobalData Report 2017) of which approximately 33% are considered resistant to current treatments (Epilepsy Foundation). It is estimated that the addressable population in the United States could include approximately 460,000 adults and 70,000 pediatric patients with focal epilepsy.