NCT05716100 · Xenon Pharmaceuticals Inc.
A Randomized Study of XEN1101 Versus Placebo in Focal-Onset Seizures (X-TOLE3)
What this study is about
The X-TOLE3 Phase 3 clinical trial is a randomly assigned, where neither patients nor doctors know which treatment is given, compared against an inactive treatment study that will evaluate the clinical effectiveness, safety and how well patients handle the treatment of XEN1101 administered as adjunctive therapy in focal-onset seizures.
View original scientific description
The X-TOLE3 Phase 3 clinical trial is a randomized, double-blind, placebo-controlled study that will evaluate the clinical efficacy, safety and tolerability of XEN1101 administered as adjunctive therapy in focal-onset seizures.
Interventions
DRUG
XEN1101
XEN1101 Capsules
DRUG
Placebo
Placebo Capsules
Primary outcome measures
Median percent change (MPC) in focal seizure frequency from baseline to DBP for XEN1101 versus placebo.
Time frame: From baseline through to the double blind period (week 12).
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Be properly informed of the nature and risks of the study and give informed consent in writing, prior to entering the study
- Diagnosis (≥2 years) of focal epilepsy according to the International League Against Epilepsy (ILAE) Classification of Epilepsy (2017). Subject must have had adequate trials of at least 2 ASMs, which were given (and tolerated) at adequate therapeutic doses, without achieving sustained seizure freedom.
- Treatment with a stable dose of 1 to 3 allowable current ASMs for at least one month prior to screening, during baseline, and throughout the duration of the DBP
- Able to keep accurate seizure diaries
Exclusion criteria
- Previously documented electroencephalogram which shows any pattern not consistent with focal etiology of seizures.
- History of focal aware non-motor seizures only, non-epileptic psychogenic seizure, primary generalized seizure, developmental and epileptic encephalopathy, including Lennox-Gastaut syndrome.
- Seizures se
Where
- Little Rock, Arkansas
- Downey, California
- Los Angeles, California
- Orange, California
- Gulf Breeze, Florida
- Jacksonville, Florida
- Boise, Idaho
- Springfield, Illinois
- Bethesda, Maryland
- Detroit, Michigan
- Hackensack, New Jersey
- Woodmere, New York
And 7 more locations — see the full list below.
Collaborators
Worldwide Clinical Trials
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced May 14, 2026 · Source of record for eligibility and locations