Phase 3 Study of XEN1101 as an Add-On Treatment for Primary Generalized Tonic-Clonic Seizures in Patients Aged 12 and Older

What this Trial Is About

Researchers are studying the use of XEN1101 as an additional treatment for people aged 12 years and older who have primary generalized tonic-clonic seizures PGTCS associated with generalized epilepsy. This Phase 3, multicenter, randomized, double-blind, placebo-controlled trial aims to assess the clinical effectiveness, safety, and tolerability of XEN1101 when added to existing anti-seizure medications. Participants are currently taking 1 to 3 anti-seizure medications and have had probable or possible PGTCS for at least one year. Participants will be randomly assigned to receive either XEN1101 or a placebo. Those aged 18 years and older will receive a 25 mg daily dose of XEN1101 or placebo. Participants aged 12 to under 18 years may receive 15 mg, 25 mg, or placebo daily. The study includes a baseline period lasting up to 9.5 weeks to track seizure frequency, followed by a 12-week double-blind treatment period where participants will take the assigned capsules once daily with an evening meal. After completing this period, participants can join an open-label extension study for continued XEN1101 treatment or enter an 8-week post-treatment follow-up if they do not enroll. During the study, participants will keep accurate seizure diaries and attend scheduled visits to monitor their health and response to treatment. Researchers will evaluate changes in monthly seizure frequency as the main outcome. Additional assessments will track safety, tolerability, and other measures throughout the treatment and follow-up periods. Overall participation may last several months, including baseline assessment, treatment, possible extension, and follow-up phases.

A Study to Evaluate XEN1101 as Adjunctive Therapy in Primary Generalized Tonic-Clonic Seizures