An Open-label Study of XEN1101 in Epilepsy

Launched by XENON PHARMACEUTICALS INC. · Feb 7, 2023

Keywords

ClinConnect Summary

This is a long-term, open-label extension study called X-TOLE4, asking how safe and tolerable XEN1101 is when used for epilepsy over up to 3 years, and how it works in the body and on seizures after previous trials. It’s not a new drug test against a placebo; all participants receive XEN1101, and researchers will track safety (adverse events), how the drug behaves in the body, and whether seizures stay under control or improve over time. The study will include up to about 880 people with focal onset seizures or a specific type of generalized seizure who completed prior trials and did not leave early. Participants take XEN1101 once daily, usually at 15 mg or 25 mg depending on age and weight, with the goal of keeping a daily seizure diary for at least 80% of days. Visits start soon after entry (2 and 4 weeks, then at 13 weeks), then every 13 weeks in the first year and every 26 weeks thereafter, with an 8-week follow-up after stopping the medication. The trial is currently enrolling by invitation and involves many sites around the world.

Key goals include safety and tolerability (the main focus), plus several measures of efficacy over time: change in monthly seizure rate, the share of people who have at least a 50% reduction in seizures, and improvements in overall severity and quality of life (as reported by clinicians and by patients). Eligibility is for anyone 12 years and older of any sex who previously completed the earlier studies and can reliably keep seizure diaries. Because this is an open-label, long-term study with no control group, results will come after many months of data collection (with completion expected in 2028). The study is sponsored by Xenon Pharmaceuticals and overseen by a data monitoring committee, with sites across multiple countries.

Gender

ALL

Eligibility criteria

• Inclusion Criteria:
• • 1. Subject must be properly informed of the nature and risks of the study and give informed consent in writing prior to entering the study (for adult subjects) and for adolescent subject's parent/legal guardian and subject gives informed consent or assent in writing prior to entering the study.
• • 2. Subject must have successfully completed the double-blind treatment period (DBP) and have not terminated early from Study X-TOLE2, X-TOLE3, or X-ACKT, met all eligibility requirements, and had no important protocol deviations (in the opinion of the sponsor) or adverse events (AEs) (in the opinion of the investigator) that would preclude the subject's entry into the long-term extension study.
• • 3. In the opinion of the investigator, the subject is able to understand verbal and written instructions and will adhere to all study schedules and requirements.
• • 4. Subject is able to keep accurate seizure diaries.
• Exclusion Criteria:
• • 1. Subject met any of the withdrawal criteria while in Study X-TOLE2, X-TOLE3, or X-ACKT.
• • 2. Subject has any medical condition, personal circumstance, or ongoing AE (from Study X-TOLE2, X-TOLE3, or X-ACKT) that, in the opinion of the investigator, exposes the subject to unacceptable risk by participating in the study, or prevents adherence to the protocol.
• • 3. Subject is planning to enter a clinical study with a different investigational drug or planning to use any experimental device for treatment of epilepsy or any other medical condition during the study and until 28 days after completion of this study.