XEN1101 (PGTCS)


XEN1101, A Differentiated KV7 Potassium Channel Opener 

We are developing XEN1101, a differentiated Kv7 potassium channel opener, for the treatment of epilepsy, major depressive disorder (MDD), and potentially other neurological disorders.

The Kv7 potassium channel mechanism has been clinically validated with ezogabine, an earlier generation Kv7 opener 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.

About XEN1101 Phase 3 Plans in Primary Generalized Tonic Clonic Seizures (PGTCS)


Xenon plans to initiate a single Phase 3 clinical trial, called X-ACKT, to support potential regulatory submission in PGTCS. This multicenter, randomized, double-blind, placebo-controlled study will evaluate the clinical efficacy and safety of XEN1101 administered as adjunctive treatment in patients with PGTCS. Approximately 160 subjects will be randomized 1:1 for once-daily dosing of XEN1101 (25 mg) or placebo. Eligibility criteria include adults aged 18 to 75 years old taking one to three ASMs with a seizure frequency of ≥3 PGTCS over an 8-week baseline period. After the baseline period to assess seizure frequency and eligibility for randomization, patients will enter a 12-week DBP. There is no titration period. The primary efficacy endpoint is the MPC in monthly PGTCS frequency from baseline through the DBP of XEN1101 compared to placebo. Key secondary endpoints include the proportion of subjects experiencing ≥50% reduction in PGTCS frequency from baseline for XEN1101 versus placebo, seizure freedom and the PGI-C at Week 12. On completion of the DBP in X-ACKT, eligible patients may enter an open-label extension study for up to three years.

For an overview of XEN1101 in PGTCS, please view: Presentation – XEN1101 in Primary Generalized Tonic Clonic Seizures (PGTCS) – June 2022




About Primary Generalized Tonic Clonic Seizures

Seizures are generally described in two major groups: generalized onset seizures and focal onset seizures. Primary generalized seizures initiate in both hemispheres of the brain simultaneously and are the second most common type of seizure experienced by people with epilepsy. PGTCS, also known as grand mal seizures or convulsions, are severe and life-threatening seizures comprised of tonic and clonic phases. Approximately 30% of patients with epilepsy have generalized seizures, which results in a total adult generalized seizure patient population of approximately 0.9 million patients in the U.S., of which at least 0.7 million patients experience PGTCS. Despite the more severe seizure phenotype, fewer ASMs are currently approved to treat PGTCS compared to FOS and approximately 30% of PGTCS patients are considered inadequately managed with initial lines of therapy warranting additional treatment options.