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Taking people in FinlandPhase 3

Tests XEN1101 against placebo for focal-onset seizures

Tests XEN1101 added to usual treatment in adults with focal-onset seizures.

Key facts

Who runs it
Xenon Pharmaceuticals Inc.
Where
Kuopio, FinlandSee the siteAlso in 20 other countries, 101 sites
Registry title
A Randomized Study of XEN1101 Versus Placebo in Focal-Onset Seizures (X-TOLE3)
Status
Recruiting
Phase
Phase 3
People taking part
360 people, planned
Started
9 May 2023
Expected to end
Mar 2028
Type of study
Interventional, 3 groupsOne group gets a placebo (a dummy treatment), for comparison.
Treatments tested
  • XEN1101
  • Placebo
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 adults who have had focal epilepsy for at least 2 years and still have seizures despite taking other seizure medicines.

Age
18 years or older
Sex
All sexes can join
Disease stage
Focal epilepsy diagnosed for at least 2 years, with seizures not fully controlled after at least 2 adequate seizure medicines (ASMs).
Earlier treatment
Must have tried at least 2 ASMs at adequate doses without lasting seizure freedom. Must be on a stable dose of 1 to 3 allowed ASMs for at least one month before screening.

Main reasons for not taking part

  • Brain wave test (EEG) showing a pattern that does not fit focal seizures
  • Only focal aware non-motor seizures, psychogenic non-epileptic seizures, primary generalized seizures, or developmental and epileptic encephalopathy such as Lennox-Gastaut syndrome
  • Seizures caused by drug or alcohol use, infection, tumour, or progressive brain or nervous system disease
  • Status epilepticus or repeated seizures in the past 12 months that cannot be counted individually
  • Brain surgery for seizures less than 1 year ago, or radiosurgery less than 2 years ago

The registry criteria, word for word

Show all 10 criteriaShow less

Who can take part

  • 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

Who cannot take part

  • Previously documented electroencephalogram which shows any pattern not consistent with focal etiology of seizures
  • History of neurosurgery for seizures <1 year prior to Visit 1, or radiosurgery <2 years prior to enrollment
  • History of focal aware non-motor seizures only, non-epileptic psychogenic seizure, primary generalized seizure, developmental and epileptic encephalopathy, including Lennox-Gastaut syndrome
  • Seizures secondary to drug or alcohol use, ongoing infection, neoplasia, demyelinating disease, degenerative neurological disease, metabolic illness, progressive structural lesion, encephalopathy, or progressive central nervous system (CNS) disease
  • History of status epilepticus or repetitive seizures within the 12-month period preceding Visit 1 where the individual seizures cannot be counted
  • Any medical condition or personal circumstance that, in the opinion of the investigator, exposes the subject to unacceptable risk by participating in the study or prevents adherence to the protocol

Where in Finland

Also in 20 other countries, 101 sites

  • Kuopio University HospitalKuopio, FinlandTaking people

About the trial

What the trial wants to find out

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.

The 3 groups in the trial

  • XEN1101 25 mg/dayTreatment being tested

    Treatment: XEN1101

  • XEN1101 15 mg/dayTreatment being tested

    Treatment: XEN1101

  • PlaceboPlacebo, for comparison

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 Randomized, Double-blind, Placebo-Controlled, Multicenter Phase 3 Study to Evaluate the Safety, Tolerability, and Efficacy of XEN1101 as Adjunctive Therapy in Focal-Onset Seizures
Plain-language title
Tests XEN1101 against placebo for focal-onset 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