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Focal EpilepsyPhase 2X-TOLENCT03796962

A Study to Evaluate XEN1101 as Adjunctive Therapy in Focal Epilepsy

A Phase 2 study testing XEN1101 in people with Focal Epilepsy, run by Xenon Pharmaceuticals Inc. at 95 sites in 9 countries.

Active, not recruiting

Under way, not looking for participants. Everyone needed has enrolled. The study is still running.

Official record
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Trial summary

The XEN1101 Phase 2 clinical trial is a randomized, double-blind, placebo-controlled study that will evaluate the clinical efficacy, safety and tolerability of increasing doses of XEN1101 administered as adjunctive treatment in adult patients diagnosed with focal epilepsy, followed by an optional open-label extension… Read more about this study

Who is it for?
Ages 18 to 75 years
Conditions the study is for
Focal Epilepsy
What is being tested?
XEN1101
Type of treatment
Pill or oral medicine
Could I receive a placebo?
Yes, some participants may receive a placebo
How many people
325 participants
Where
95 sitesin 9 countries
Study dates
30 Jan 2019to Oct 2030
Phase
Phase 2
Are there results?
Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 to 75 years
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • Be properly informed of the nature and risks of the study and give informed consent in writing, prior to entering the study
  • BMI ≤40 kg/m2
  • Diagnosis (≥2 years) of focal epilepsy according to the International League Against Epilepsy [ILAE] Classification of Epilepsy (2017)
  • Prior neuroimaging within the last 10 years and documentation is available
  • Treatment with a stable dose of 1 to 3 allowable current AEDs for at least one month prior to screening, during baseline, and throughout the duration of the DBP
  • Must be willing to comply with the contraception requirements
  • Males must agree not to donate sperm from the time of the first administration of study drug until 3 months after the last dose. Females must agree not to donate ova from the time of the first administration of study drug until 3 months after the last dose.
  • Able to keep accurate seizure diaries

Who cannot join

  • History of pseudoseizures, psychogenic seizures, primary generalized seizure, or focal aware non-motor seizures only
  • Presence or previous history of Lennox-Gastaut syndrome
  • Seizures secondary to other diseases or conditions
  • History of repetitive seizures within the last 12 months where the individual seizures cannot be counted
  • History of neurosurgery for seizures <1 year prior to enrollment, or radiosurgery <2 years prior to enrollment
  • Schizophrenia and other psychotic disorders, or active suicidal plan/intent in the past 6 months, or a history of suicide attempt in the last 2 years, or more than 1 lifetime suicide attempt
Show all 14Show fewer
  • History or presence of any significant medical or surgical condition or uncontrolled medical illness at screening, or history of cancer within the past 2 years, with the exception of appropriately treated basal cell or squamous cell carcinoma
  • Any clinically significant abnormalities on pre-study physical examination, vital signs, laboratory values or ECG indicating a medical problem that would preclude study participation including but not limited to:
  • History of presence of long QT syndrome; QTcF > 450 msec at baseline; family history of sudden death of unknown cause
  • History of skin or retinal pigment epithelium abnormalities caused by ezogabine
  • Past use of vigabatrin without stable visual fields tested twice over the 12 months after the last dose of vigabatrin (concomitant use of vigabatrin is not allowed)
  • If felbamate is used as a concomitant AED, patients must be taking it for at least 2 years, with a stable dose for 2 months (or no less than 49 days) and acceptable hematology and LFT history and values prior to Screening. If received in the past, felbamate must have been discontinued 2 months (or no less than 49 days) prior to Screening.
  • Have had multiple drug allergies or a severe drug reaction to an AED(s), including dermatological (e.g., Stevens-Johnson syndrome), hematological, or organ toxicity reactions
  • Current use of a ketogenic diet

Trial locations and contacts

95 sites in 9 countries.

95 sites in 9 countries

United States54 sites

  • Dent Neurosciences Research Center

    Amherst, New York, 14226

  • Asheville Neurology Specialists, PA

    Asheville, North Carolina, 28806

  • University of Colorado Hospital Anschutz Outpatient Pavilion

    Aurora, Colorado, 80045

  • Austin Epilepsy Care Center

    Austin, Texas, 78758

  • Mid-Atlantic Epilepsy and Sleep Center

    Bethesda, Maryland, 20817

  • University of Alabama at Birmingham

    Birmingham, Alabama, 35294

  • Consultants in Epilepsy and Neurology, PLLC

    Boise, Idaho, 83702

  • University of Virginia

    Charlottesville, Virginia, 22903

  • Northwestern Medical Group, Department of Neurology

    Chicago, Illinois, 60611

  • UC Gardner Neuroscience Institute

    Cincinnati, Ohio, 45219

  • James W. Aston Ambulatory Care Center

    Dallas, Texas, 75390

  • Miami Valley Hospital

    Dayton, Ohio, 45409

  • Minneapolis Clinic of Neurology, Ltd.

    Golden Valley, Minnesota, 55422

  • Northeast Regional Epilepsy Group

    Hackensack, New Jersey, 07601

  • Hawaii Pacific Neuroscience

    Honolulu, Hawaii, 96817

  • University of Florida Jacksonville

    Jacksonville, Florida, 32209

  • Mayo Clinic Florida

    Jacksonville, Florida, 32224

  • University of Kansas Medical Center

    Kansas City, Kansas, 66160

  • Altman Clinical Translational Research Institute (ACTRI)

    La Jolla, California, 92037

  • Bluegrass Epilepsy Research

    Lexington, Kentucky, 40504

  • Clinical Trials, Inc.

    Little Rock, Arkansas, 72205

  • Institute of Neurology and Neurosurgery at Saint Barnabas

    Livingston, New Jersey, 07039

  • Visionary Investigators Network

    Miami, Florida, 33133

  • Don Clinical Research Center

    Miami, Florida, 33136

  • The Neurology Research Group, LLC.

    Miami, Florida, 33176

  • Strada Patient Care Center

    Mobile, Alabama, 36604

  • Northeast Regional Epilepsy Group

    Morristown, New Jersey, 07960

  • Vanderbilt Epilepsy Clinic

    Nashville, Tennessee, 37232

  • NYU Langone Medical Center/NYU School of Medicine

    New York, New York, 10016

  • Northwell Health - Lenox Hill

    New York, New York, 10075

  • Research Institute of Orlando, LLC

    Orlando, Florida, 32806

  • Hospital of the University of Pennsylvania

    Philadelphia, Pennsylvania, 19104

  • Thomas Jefferson University Comprehensive Epilepsy Center

    Philadelphia, Pennsylvania, 19107

  • Xenoscience, Inc.

    Phoenix, Arizona, 85004

  • Allegheny Neurological Associates

    Pittsburgh, Pennsylvania, 15212

  • Medsol Clinical Research Center

    Port Charlotte, Florida, 33952

  • Providence Neurological Specialties East

    Portland, Oregon, 97213

  • UW Medicine Valle Medical Center

    Renton, Washington, 98055

  • Virginia Commonwealth University

    Richmond, Virginia, 23219

  • Carilion Neurology Clinic

    Roanoke, Virginia, 24016

  • Boston Neuro Research Center

    Russells Mills, Massachusetts, 02747

  • Minnesota Epilepsy Group, P. A.

    Saint Paul, Minnesota, 55102

  • University of Utah Health Clinical Neurosciences Center

    Salt Lake City, Utah, 84132

  • The University of Texas Health Science Center at San Antonio

    San Antonio, Texas, 78229-3900

  • California Pacific Medical Center (CPMC) - Sutter Pacific Epilepsy Program

    San Francisco, California, 94109

  • Maine Medical Partners Neurology

    Scarborough, Maine, 04074

  • University of Washington School of Medicine, Regional Epilepsy Center at Harborview Medical Center

    Seattle, Washington, 98104

  • Georgia Neurology and Sleep Medicine Associate

    Suwanee, Georgia, 30024

  • SUNY Upstate Medical University Institute for Human Performance

    Syracuse, New York, 13210

  • Tallahassee Neurological Clinic

    Tallahassee, Florida, 32308

  • University of South Florida

    Tampa, Florida, 33606

  • University of Toledo Medical Center

    Toledo, Ohio, 43606

  • Winchester Neurological Consultants

    Winchester, Virginia, 22601

  • Five Towns Neuroscience Research

    Woodmere, New York, 11598

Other trials in United States

Spain15 sites

  • Hospital Germans Trias I Pujol

    Badalona, Barcelona, 08916

  • Hospital del Mar

    Barcelona, Barcelona, 08003

  • Hospital Universitario Vall d'Hebron

    Barcelona, Barcelona, 08035

  • Hospital Vithas La Salud

    Granada, Granada, 18008

  • Hospital U. Ramón y Cajal

    Madrid, Madrid, 28034

  • Hospital Ruber Internacional

    Madrid, Madrid, 28036

  • Hospital U. Clínico San Carlos

    Madrid, Madrid, 28040

  • Hospital Universitario Fundacion Jimenez Diaz

    Madrid, Madrid, 28040

  • Hospital Universitario 12 de Octubre

    Madrid, Madrid, 28041

  • Hospital Regional Universitario de Málaga

    Málaga, Málaga, 29010

  • Clínica Universidad Navarra

    Pamplona, Navarre, 31008

  • Hospital Virgen Macarena

    Seville, Andalusia, 41009

  • Centro de Neurologia Avanzada

    Seville, Andalusia, 41013

  • Hospital Universitario y Politécnico La Fe

    Valencia, Valencia, 46026

  • Hospital Clínico Universitario Valladolid

    Valladolid, Valladolid, 47003

Other trials in Spain

Germany9 sites

  • Epilepsiezentrum Berlin-Brandenburg

    Berlin, 10365

  • Bethel Epilepsy Centre

    Bielefeld, 33617

  • Univ.-Klinik Bonn, Klinik und Poliklinik fur Epileptologie

    Bonn, 53127

  • Universitatsklinikym Frankfurt

    Frankfurt, 60528

  • Universitatsklinikum Freiburg, Neurozentrum/Epilepsiezentrum

    Freiburg im Breisgau, 79106

  • University Hospital Munster (UKM)

    Münster, 48149

  • Klinikum Osnabruck

    Osnabrück, 49076

  • Krankenhaus Barmherzige Brueder Regensburg

    Regensburg, 93049

  • University of Tubingen-Dept. of Neurology and Epileptology

    Tübingen, 72076

Other trials in Germany

Italy7 sites

  • IRCCS- Istituto delle Scienze Neurologiche, Bellaria Hospital

    Bologna, Bologna, 40139

  • Dipartimento Scienze Mediche e Chirurgiche, Universita Magna Graecia di Catanzaro

    Catanzaro, Catanzaro, 88100

  • Fondazione IRCCS Istituto Neurologico C. Besta

    Milan, Milano, 20133

  • IRCCS Istituto Neurologico Nazionale C. Mondino

    Pavia, Pavia, 27100

  • Azienda Ospedaliera Universita' Pisana

    Pisa, Pisa, 56124

  • Azienda Ospedaliera "Bianchi-Melacrino-Morelle"di Reggio Calabria

    Reggio Calabria, Reggio Calabria, 89123

  • Policlinico di Roma Umberto I

    Roma, Roma, 00185

Other trials in Italy

United Kingdom4 sites

  • University Hospital of Wales

    Cardiff, Wales, CF14 4XW

  • Institute of Neurological Sciences

    Glasgow, Scotland, G514TF

  • King's College Hospital NHS Foundation Trust

    London, London, SE5 9RS

  • St. George's University Hospitals NHS Foundation Trust

    London, London, SW17 0QT

Other trials in United Kingdom

Canada3 sites

  • London Health Sciences Center

    London, Ontario, N6A 5A5

  • University Health Network-Toronto Western Hospital

    Toronto, Ontario, M5T 2S8

  • Children's and Women's Health Centre of British Columbia (BC Children's Hospital)

    Vancouver, British Columbia, V6H 3V4

Other trials in Canada

Georgia1 site

  • LLC Arensia Exploratory Medicine

    Tbilisi, 0112

Other trials in Georgia

Moldova1 site

  • PMSI Republican Clinical Hospital, ARENSIA Exploratory Medicine

    Chisinau, 2025

Other trials in Moldova

Ukraine1 site

  • Medical Center of Limited Liability Company "Harmoniya Krasy"

    Kyiv, Kyiv Oblast, 01135

Other trials in Ukraine

About this study

Official title: A Randomized, Double-blind, Placebo-controlled, Multicenter Study to Evaluate the Safety, Tolerability and Efficacy of XEN1101 as Adjunctive Therapy in Focal-onset Epilepsy, With an Open-label Extension

The XEN1101 Phase 2 clinical trial is a randomized, double-blind, placebo-controlled study that will evaluate the clinical efficacy, safety and tolerability of increasing doses of XEN1101 administered as adjunctive treatment in adult patients diagnosed with focal epilepsy, followed by an optional open-label extension (OLE).

Read the detailed description

The XEN1101 Phase 2 clinical trial is designed as a randomized, double-blind, placebo-controlled, multicenter study with an optional open-label extension (OLE) to evaluate the clinical efficacy, safety and tolerability of XEN1101 administered as adjunctive treatment in adult patients aged 18 to 75 years diagnosed with focal epilepsy. Approximately 300 patients will be randomized in a blinded manner to one of three active treatment groups or placebo in a 2:1:1:2 fashion (XEN1101 25 mg : 20 mg : 10 mg : Placebo). After screening, patients will have 8 weeks of baseline to assess frequency of seizures, followed by 8 weeks of treatment and a 6-week post treatment follow-up period. In order to be included in the study, patients must already be treated with a stable dose of 1 to 3 allowable current anti-epileptic drugs for at least one month prior to screening, during baseline, and throughout the double-blind portion (DBP) of the study. During the treatment period, patients will be given XEN1101 or placebo once daily in the evening. An OLE will be available to eligible patients who complete the DBP. All patients will receive a 20 mg daily dose of XEN1101 during this extension period.

Conditions
Focal Epilepsy
Being tested
XEN1101
Keywords
Epilepsy
Medical subject headings
Epilepsies, Partial, Epilepsy

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • XEN1101Drug

    Oral dose

Study groups in NCT03796962
Study groupRoleWhat they receive
25 mg XEN1101ExperimentalCapsule filled with 25 mg XEN1101
Receives: Drug: XEN1101
20 mg XEN1101ExperimentalCapsule filled with 20 mg XEN1101
Receives: Drug: XEN1101
10 mg XEN1101ExperimentalCapsule filled with 10 mg XEN1101
Receives: Drug: XEN1101
PlaceboPlacebo comparatorPlacebo capsule
Receives: Drug: XEN1101

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Median Percent Change in Focal Seizure Frequency

    Median percent change in monthly (28 days) focal seizure frequency from baseline to DBP for XEN1101 versus placebo

    Measured: From baseline (8 weeks prior to Day 0) through to the final dose (up to Day 56)

Secondary outcomes (2)

  1. 50% XEN1101 Response Rate

    Responders are defined as patients experiencing ≥50% reduction in monthly (28 days) focal seizure frequency from baseline to DBP

    Measured: From baseline (8 weeks prior to Day 0) through to the final dose (up to Day 56)

  2. Percent Change in Focal Seizure Frequency Over Time

    Percent change from baseline in focal seizure frequency at Month 1 and Month 2 in the DBP

    Measured: From baseline (8 weeks prior to Day 0) through to the final dose (up to Day 56)

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted8 Jan 2019
  2. Study start30 Jan 2019
  3. Primary completion2 Sep 2021
  4. Study completionOct 2030 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 2
Primary purpose
Treatment
Allocation
Randomised
Intervention model
Parallel groups
Masking
Quadruple blind
Who is masked
Participant, Care provider, Investigator, Outcomes assessor
Enrolment
325 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT03796962
Sponsor's protocol ID
XPF-008-201
Other IDs
2018-003221-29, 2023-508681-15-00, 2023, 2018
Acronym
X-TOLE
Status last verified
Oct 2026
First submitted
2 Jan 2019
Last updated
5 Nov 2026
Data monitoring committee
No
FDA-regulated drug
Yes
FDA-regulated device
No

Publications

  • French JA, Porter RJ, Perucca E, Brodie MJ, Rogawski MA, Pimstone S, Aycardi E, Harden C, Qian J, Rosenblut CL, Kenney C, Beatch GN; X-TOLE Study Group. Efficacy and Safety of XEN1101, a Novel Potassium Channel Opener, in Adults With Focal Epilepsy: A Phase 2b Randomized Clinical Trial. JAMA Neurol. 2023 Nov 1;80(11):1145-1154. doi: 10.1001/jamaneurol.2023.3542.

    PubMed 37812429

Questions about this trial

What is this clinical trial studying?

A Phase 2 study testing XEN1101 in people with Focal Epilepsy, run by Xenon Pharmaceuticals Inc. at 95 sites in 9 countries.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 8 inclusion and 14 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: under way, not looking for participants, as of the sponsor's last update on 5 Nov 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 95 sites in United States, Spain, Germany, Italy, United Kingdom and 4 more countries. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

Yes. Results are posted in the registry (first posted 24 Sep 2024). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Median Percent Change in Focal Seizure Frequency (time frame: From baseline (8 weeks prior to Day 0) through to the final dose (up to Day 56)). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT03796962, which also lists 1 linked publication.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 5 Nov 2026.

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