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Taking people in CzechiaPhase 3

Long-term study of XEN1101 for epilepsy with seizures

Tests XEN1101 long term in people aged 12 or older with epilepsy.

Key facts

Who runs it
Xenon Pharmaceuticals Inc.
Where
Hradec Králové, Prague 5, and Prague 6, CzechiaSee the 3 sitesAlso in 25 other countries, 170 sites
Registry title
An Open-label Study of XEN1101 in Epilepsy
Status
Enrolling by invitation
Phase
Phase 3
People taking part
880 people, planned
Started
25 Apr 2023
Expected to end
Jun 2033
Type of study
Interventional
Treatments tested
  • XEN1101
Record updated
2 November 2026

Who can take part

AI summary

From the trial's eligibility criteria. Machine-read from the registry text on this page, so it can be wrong. The registry text below and the trial team decide who can take part.

The trial is looking for people with focal-onset seizures or primary generalized tonic-clonic seizures who finished an earlier XEN1101 study (X-TOLE2, X-TOLE3 or X-ACKT). It checks long-term safety and effect of XEN1101.

Age
12 years and older
Sex
All sexes can join.
Disease stage
Focal-onset seizures or primary generalized tonic-clonic seizures.
Earlier treatment
Must have finished the double-blind treatment period of study X-TOLE2, X-TOLE3 or X-ACKT without leaving early.

Main reasons for not taking part

  • Met any withdrawal criteria in study X-TOLE2, X-TOLE3 or X-ACKT
  • A medical condition, personal circumstance or ongoing side effect that the investigator sees as an unacceptable risk or that prevents following the protocol
  • Planning to join a study of a different investigational drug or use an experimental device for epilepsy or another condition until 28 days after this study ends

The registry criteria, word for word

Show all 7 criteriaShow less

Who can take part

  • 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
  • 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
  • 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
  • Subject is able to keep accurate seizure diaries

Who cannot take part

  • 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
  • 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
  • Subject met any of the withdrawal criteria while in Study X-TOLE2, X-TOLE3, or X-ACKT

Where in Czechia

Also in 25 other countries, 170 sites

  • MUDr. Helena Hojdíková, Neurologie, s.r.o.Hradec Králové, CzechiaTaking people
  • Fakultni Nemocnice V MotolePrague 5, CzechiaTaking people
  • Forbeli s.r.o.Prague 6, CzechiaTaking people

About the trial

What the trial wants to find out

This study will evaluate the long term safety, tolerability, pharmacokinetics (PK), and efficacy of XEN1101 in subjects with Focal Onset Seizures (FOS) or Primary Generalized Tonic-Clonic Seizures (PGTCS) for the treatment of seizures for up to 6 years.

The group in the trial

  • XEN1101 15 or 25 mg/dayTreatment being tested

    Treatment: XEN1101

Questions to ask the study team

  1. How often do I need to come in, and for how long each time?
  2. Are travel costs paid?
  3. Can I keep my own doctor?
  4. What happens if I want to stop?

Contact the study team: see the registry record → Contacts and Locations

Print a page for my doctor

Data and sources

Registry record
Listed on ClinicalTrials.gov and on the EU's official list of trials (CTIS).
Official title
A Multicenter, Open-label, Long-term, Safety, Tolerability, and Efficacy Study of XEN1101 in Subjects Diagnosed With Epilepsy
Plain-language title
Long-term study of XEN1101 for epilepsy with seizuresGenerated from the registry record. The registry title is the official one.
AI summary
From the trial's eligibility criteria. Read by machine on 12 November 2026.
Record updated
2 November 2026