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Lennox Gastaut SyndromePhase 3NCT05066217

An Efficacy and Safety Study of Clemizole HCl in Patients With Lennox-Gastaut Syndrome

A Phase 3 study testing Clemizole HCl in people with Lennox Gastaut Syndrome, run by Epygenix at 71 sites in 10 countries.

Recruiting

Looking for participants now. Contact the study team or a site below to ask about taking part.

Sites and contacts
Official record
Search all trials

Trial summary

This is a multicenter, Phase 3, randomized, double-blind, placebo-controlled study designed to evaluate the efficacy and safety of clemizole HCL (EPX-100) as adjunctive therapy in children and adult participants with Lennox-Gastaut syndrome (LGS). Read more about this study

Who is it for?
Ages 2 to 55 years
Conditions the study is for
Lennox Gastaut Syndrome
What is being tested?
Clemizole HCl
Type of treatment
Pill or oral medicine
Could I receive a placebo?
Yes, some participants may receive a placebo
How many people
260 participants
Where
71 sitesin 10 countries
Study dates
9 Apr 2025to 1 Nov 2029
Phase
Phase 3
Are there results?
Not yet: the study is under way

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 2 to 55 years
  • All sexes
  • No healthy volunteers
  • Child, Adult

Who may be able to join

  • Males or females, ages ≥2 to ≤55 years, at the time of Screening.
  • Participant/parent/legal authorized representative (LAR) willing and able to give written informed consent/assent.
  • Diagnosis of LGS, including:
  • Evidence of at least one type of countable major motor seizure.
  • History of electroencephalogram (EEG) consistent with LGS (abnormal background activity, and one of the following: 1) slow spike-wave discharges [<2.5 Hz], or 2) paroxysmal fast activity during sleep).
  • Abnormal cognitive development.
  • Onset of seizures at 11 years of age or younger.

Who cannot join

  • Known sensitivity, allergy, or previous exposure to clemizole HCl.
  • Known history of long QT syndrome or any significant history of a serious abnormality of the electrocardiogram (ECG) (e.g., recent myocardial infarction, clinically significant arrhythmia).
  • Family history of sudden cardiac death, unexplained death, or death from a primary dysrhythmia potentially associated with QT prolongation in any family member.
  • Seizures secondary to illicit drug or alcohol use, infection, neoplasm, demyelinating disease, degenerative neurological disease, or progressive central nervous system disease, metabolic illness, recent anoxic episode within the last 6 months requiring resuscitation, or progressive degenerative disease or any other condition, which in the opinion of the investigator, could affect seizure control.
  • Epilepsy surgery planned during the study or epilepsy surgery within 6 months prior to Screening.
  • Concomitant use of fenfluramine.
  • Prior or concomitant use of lorcaserin.

Trial locations and contacts

71 sites in 10 countries. Contact the study team or a site near you to ask about taking part.

Juby Philip contact

(302) 559-4320

clinicaltrials@harmonybiosciences.com

Cindy Sandy contact

(317) 258-7262

clinicaltrials@harmonybiosciences.com

71 sites in 10 countries

United States22 sites, 17 recruiting

  • Atrium Health STRIVE Research

    Charlotte, North Carolina, 28207

    Jessica Lindley, Jessica.Lindley@atriumhealth.org

    Ravi Singh, MD

    Recruiting

  • On-Site Clinical Solution

    Charlotte, North Carolina, 28211

    Ludny Saintil, 800-785-3150 ext. 198, ludny.santil@thermofischer.com

    Robert Nahouraii

    Recruiting

  • Re:Cognition Health

    Chicago, Illinois, 60611

    Antonio Iglesias, MD, 312-971-3318, aiglesias@re-cognitionhealth.com

    Antonio Iglesias, MD

    Recruiting

  • Children's Health Specialty Center

    Dallas, Texas, 75235

    Charuta Joshi

    Recruiting

  • Henry Ford Hospital

    Detroit, Michigan, 48202

    Active, not recruiting

  • Duke University Medical Center

    Durham, North Carolina, 27705

    Muhammad Zafar, MD, muhammad.zafar@duke.edu

    Muhammad Zafar, MD

    Recruiting

  • UTHealth Houston

    Houston, Texas, 77030

    Antoinette Bernal-Tent, 713-500-7105, Antoinette.BernalTent@uth.tmc.edu

    Mary Koenig, MD

    Recruiting

  • Arkansas Children's Hospital

    Little Rock, Arkansas, 72202

    Active, not recruiting

  • Norton Children's Medical Center

    Louisville, Kentucky, 40202

    Madeline McGinty-Holmes, 502-629-5568, madeline.mcginty-holmes@louisville.edu

    Jaime Shoup, MD

    Recruiting

  • Tekton Research

    Marlboro, New Jersey, 07746

    Aimee Kinlan, 626-218-8294, aimee.kinlan@tektonresearch.com

    Amor Mehta, MD

    Recruiting

  • University of Miami Miller School of Medicine

    Miami, Florida, 33136

    Brett Alonso Cardenas, 305-243-3100, bac301@med.miami.edu

    Kamil Detyniecki, MD

    Recruiting

  • PPD Virtual-Science 37, Inc.

    Morrisville, North Carolina, 27560

    Victoria Taylor, 615-707-9148, victoria.taylor@science37.com

    Antonio Iglesias, MD

    Recruiting

  • NYU Comprehensive Epilepsy Center - BRANY - PPDS

    New York, New York, 10016-4852

    Dana Price

    Recruiting

  • Weill Cornell Medicine/New York Presbyterian Hospital

    New York, New York, 10021

    Lundy Santil, 800-785-3150 ext. Ext. 198, ludny.saintil@thermofisher.com

    Asim Shahid, los9075@med.cornell.edu

    Recruiting

  • Children's Nebraska

    Omaha, Nebraska, 68114

    Sookyong Koh, MD, PhD, 773-929-4445, skoh@childrensnebraska.org

    Sookyong Koh

    Recruiting

  • UC Irvine Medical Center

    Orange, California, 92868

    Active, not recruiting

  • AdventHealth Innovation Tower

    Orlando, Florida, 32804

    Holly Skinner, DO

    Recruiting

  • Rare Disease Research

    Orlando, Florida, 34746

    Suspended

  • Children's Hospital of Philadelphia

    Philadelphia, Pennsylvania, 19104

    Eric Marsh, MD

    Recruiting

  • Minnesota Epilepsy Group, P.A.

    Roseville, Minnesota, 55102

    Sarah Ellis, MD, 651-377-8319, sellis@mnepilepsy.net

    Stephanie Ahrens, MD

    Recruiting

  • Clinical Neurosciences Center

    Salt Lake City, Utah, 84132

    Angela Peters, MD

    Recruiting

  • Pediatric Neurology and Epilepsy Specialists

    Winter Park, Florida, 32789

    Active, not recruiting

Other trials in United States

China18 sites, 18 recruiting

  • Peking University First Hospital - Changqiao Campus

    Beijing, 100034

    Yuwu Jiang

    Recruiting

  • Peking University First Hospital - Daxing Campus

    Beijing, 100034

    Yuwu Jiang

    Recruiting

  • Beijing Children's Hospital, Capital Medical University - PIN

    Beijing, 100045

    Hui Xiong

    Recruiting

  • The First Hospital of Jilin University

    Changchun, 130021

    Jianmin Liang

    Recruiting

  • Xiangya Hospital Central South University

    Changsha, Hunan, 410008

    Jing Peng

    Recruiting

  • Hunan Children's Hospital

    Changsha, 410007

    Sai Yang

    Recruiting

  • West China Second University Hospital, Sichuan University - Huaxi Campus

    Chengdu, 610041

    Rong Luo

    Recruiting

  • Chengdu Women's and Children's Central Hospital

    Chengdu, 610073

    Li Yan

    Recruiting

  • Children's Hospital of Chongqing Medical University

    Chongqing, 400014

    Li Jiang

    Recruiting

  • The Second Affiliated Hospital of Guangzhou Medical University

    Guangzhou, 510260

    Xiaorong Liu

    Recruiting

  • The Affiliated Hospital of Guizhou Medical University

    Guiyang, 550004

    Rong Ai

    Recruiting

  • Qilu Hospital of Shandong University

    Jinan, 250012

    Baomin Li

    Recruiting

  • Jiangxi Provincial Children's Hospital

    Nanchang, 330006

    Yong Chen

    Recruiting

  • Children's Hospital of Shanghai

    Shanghai, Shanghai Municipality, 200062

    Simei Wang

    Recruiting

  • Shenzhen Children's Hospital

    Shenzhen, 518000

    Dezhi Cao

    Recruiting

  • Wuhan Children's Hospital

    Wuhan, 430015

    Dan Sun

    Recruiting

  • The Second Affiliated Hospital of Xi'an Jiaotong University

    Xi'an, 710004

    Lin Yang

    Recruiting

  • Xuzhou Children's Hospital

    Xuzhou, 221006

    Xiaoming Liu

    Recruiting

Other trials in China

Italy7 sites, 7 recruiting

  • Azienda Ospedaliera Universitaria Renato Dulbecco - AO Mater Domini

    Catanzaro, 88100

    Antonio Gambardella

    Recruiting

  • Azienda Ospedaliero Universitaria A Meyer

    Florence, 50139

    Renzo Guerrini

    Recruiting

  • IRCCS Azienda Ospedaliera Metropolitan

    Genoa, Liguria, 16132

    Flavio Villani

    Recruiting

  • IRCCS Istituto Giannina Gaslini

    Genoa, Liguria, 16147

    Maria Margherita Mancardi

    Recruiting

  • Fondazione IRCCS Istituto Neurologico Carlo Besta

    Milan, 20133

    Giuseppe Didato

    Recruiting

  • Fondazione Istituto Neurologico Nazionale Casimiro Mondino IRCCS

    Pavia, 27100

    Elena Tartara

    Recruiting

  • IRCCS Istituto Neurologico Mediterraneo Neuromed

    Pozzilli, Molise, 86077

    Alfredo D'Aniello

    Recruiting

Other trials in Italy

Spain6 sites, 6 recruiting

  • Hospital de La Santa Creu i Sant Pau

    Barcelona, 08025

    Alba Sierra-Marcos

    Recruiting

  • Hospital Universitario Vall d'Hebron - PPDS

    Barcelona, 08035

    Manuel Toledo Argany

    Recruiting

  • Hospital Infantil Universitario Niño Jesus - PIN

    Madrid, 28009

    Victor Soto Insuga

    Recruiting

  • Hospital Regional Universitario de Malaga - Hospital General

    Málaga, 29010

    Pedro Serrano

    Recruiting

  • Hospital Universitario de Navarra

    Pamplona, 31008

    Sergio Aguilera Albesa

    Recruiting

  • Centro de Neurologia Avanzada

    Seville, 41013

    Juan Jesús Rodríguez Uranga, MD

    Recruiting

Other trials in Spain

India5 sites, 5 recruiting

  • Royal Institute of Child Neurosciences

    Ahmedabad, Gujarat, 380054

    Nitish Vora

    Recruiting

  • Aster Malabar Institute of Medical Sciences Ltd

    Calicut, Kerala, 673016

    Smilu Mohanlal

    Recruiting

  • Yashoda Hospitals Hitec City

    Hyderabad, Andhra Pradesh, 500081

    Lokesh Lingappa

    Recruiting

  • Nizams Institute of Medical Sciences

    Hyderabad, Andhra Pradesh, 500082

    Surya Prabha Turaga

    Recruiting

  • Saachi Children Hospital

    Surat, Gujarat, 395002

    Ritesh Shah

    Recruiting

Other trials in India

Serbia4 sites, 4 recruiting

  • Childrens University Hospital

    Belgrade, 11000

    Dimitrije Nikolic

    Recruiting

  • Mother and Child Health Care Institute of Serbia Dr Vukan Cupic

    Belgrade, 11000

    Biljana Vucetic Tadic

    Recruiting

  • University Clinical Center Nis

    Niš, 18 000

    Tatjana Tosic

    Recruiting

  • Children and Youth Health Care Institute of Vojvodina

    Novi Sad, 21000

    Tatjana Redzek Mudrinic

    Recruiting

Other trials in Serbia

Poland3 sites, 3 recruiting

  • Centrum Medyczne Plejady Magdalena Celinska

    Krakow, Lesser Poland Voivodeship, 30-363

    Marta Zolnowska, MD

    Recruiting

  • Neurosphera

    Warsaw, Masovian Voivodeship, 02-829

    Beata Zwolinska

    Recruiting

  • Premium Clinic Wrocław Centrum Medyczne

    Wroclaw, Lower Silesian Voivodeship, 50-414

    Monika Sluzewska-Niedzwiedz

    Recruiting

Other trials in Poland

Romania3 sites, 3 recruiting

  • Centrul National Clinic De Recuperare Neuropsihomotorie Copii Robanescu-Padure

    Bucharest, 041408

    Madalina Leanca

    Recruiting

  • Emergency University Hospital

    Bucharest, 050098

    Ioana Raluca Mindruta

    Recruiting

  • Sf. Maria Children Emergency Clinical Hospital Iasi

    Iași, 700309

    Ioana Grigore

    Recruiting

Other trials in Romania

Turkey (Türkiye)2 sites, 2 recruiting

  • Eskisehir Osmangazi Universitesi Saglik Uygulama ve Arastirma Hastanesi

    Odunpazari, Eskişehir, 26040

    Kursat Carman

    Recruiting

  • Karadeniz Teknik Universitesi Farabi Hastanesi

    Ortahisar, 61080

    Ali Cansu

    Recruiting

Other trials in Turkey (Türkiye)

Hungary1 site, 1 recruiting

  • Debreceni Egyetem Klinikai Kozpont Nagyerdei Campus

    Debrecen, Hajdú-Bihar, 4032

    Monika Bessenyei

    Recruiting

Other trials in Hungary

About this study

Official title: Multicenter, Randomized, Double-blind, Placebo-controlled Trial of Clemizole HCl as Adjunctive Therapy in Patients With Lennox-Gastaut Syndrome

This is a multicenter, Phase 3, randomized, double-blind, placebo-controlled study designed to evaluate the efficacy and safety of clemizole HCL (EPX-100) as adjunctive therapy in children and adult participants with Lennox-Gastaut syndrome (LGS).

Read the detailed description

This is a multicenter, Phase 3, randomized, double-blind, placebo-controlled study designed to evaluate the efficacy and safety of clemizole HCl as adjunctive therapy in children and adult participants with LGS.

The study will consist of an Observational Period, a Double-Blind (DB) Period, and an optional Open-Label Extension (OLE) Period.

Being tested
Clemizole HCl, Placebo
Keywords
Lennox Gastaut Syndrome, Lennox-Gastaut Syndrome, LGS, Clemizole HCl, Seizure
Medical subject headings
Lennox Gastaut Syndrome, Seizures

What participants receive

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

  • Clemizole HClDrug

    Also called EPX-100

    Clemizole HCl will be administered as an oral solution.

  • PlaceboDrug

    Placebo will be administered as an oral solution.

Study groups in NCT05066217
Study groupRoleWhat they receive
PlaceboPlacebo comparatorParticipants will receive their first dose of study drug following randomization.
Receives: Drug: Placebo
Double-blind clemizole HClExperimentalParticipants will receive their first dose of study drug following randomization.
Receives: Drug: Clemizole HCl
Open-label clemizole HClExperimentalEligible participants who complete the DB Period will have the option to continue in the OLE Period, during which they will receive clemizole HCl for up to 3 years.
Receives: Drug: Clemizole HCl

What is being measured

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

  1. Percent Change in CMMS-28

    Percent change in CMMS-28 from the Baseline Period through the end of the DB Period

    Measured: From Baseline Period up to 16 weeks

Secondary outcomes (10)

  1. Proportion of Participants with ≥50% Reduction in CMMS-28

    Proportion of participants with ≥50% reduction in CMMS-28 from the Baseline Period through the end of the DB Period

    Measured: From Baseline Period up to 16 weeks

  2. Percent Change in CMMS-28 Seizure-free Days

    Percent change in CMMS-28 seizure-free days from the Baseline Period through the end of the DB Period

    Measured: From Baseline Period up to 16 weeks

  3. Clinical Global Impression of Change (CGI-C) Score

    CGI-C score at the end of the DB Period

    Measured: Week 16

  4. Caregiver Global Impression of Change (CaGI-C) Score

    CaGI-C score at the end of the DB Period

    Measured: Week 16

  5. Caregiver Global Impression of Change in Seizure Intensity/Duration (CaGI-CSID) Score

    CaGI-CSID score at the end of the DB Period

    Measured: Week 16

  6. Change in Quality of Life Inventory (QI)-Disability Score

    Change in QI-disability score from Baseline to the end of the DB Period

    Measured: From Baseline Period up to 16 weeks

  7. Percent Change per 28 Days in the Number of Seizure Free Days

    Percent change per 28 days in the number of seizure-free days (based on all seizure types) from the Baseline Period through the end of the DB Period

    Measured: From Baseline Period up to 16 weeks

  8. Percent Change in CMMS-28

    Percent change in CMMS-28 from the Baseline Period through the end of the DB Maintenance Phase only

    Measured: From Baseline Period up to 12 weeks

  9. Proportion of Participants with ≥50% Reduction in CMMS-28

    Proportion of participants with ≥50% reduction in CMMS-28 from the Baseline Period through the end of the DB Maintenance Phase only

    Measured: From Baseline Period up to 12 weeks

  10. Incidence of Treatment-Emergent Adverse Events (TEAEs)

    Incidence of TEAEs will be compared among the treatment groups

    Measured: From the first dose administration of study drug up to end of the study, approximately up to 172 weeks

Timeline

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

  1. First posted4 Oct 2021
  2. Study start9 Apr 2025
  3. Primary completion1 Nov 2026 (estimated)
  4. Study completion1 Nov 2029 (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 3
Primary purpose
Treatment
Allocation
Randomised
Intervention model
Parallel groups
Model description
Patients are randomized 1:1 to clemizole HCl (EPX-100) or placebo.
Masking
Triple blind
Who is masked
Participant, Care provider, Investigator
Enrolment
260 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT05066217
Sponsor's protocol ID
EPX-100-003
Status last verified
Oct 2026
First submitted
23 Sep 2021
Last updated
9 Oct 2026
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
No

Questions about this trial

What is this clinical trial studying?

A Phase 3 study testing Clemizole HCl in people with Lennox Gastaut Syndrome, run by Epygenix at 71 sites in 10 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 7 inclusion and 7 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: looking for participants now, as of the sponsor's last update on 9 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 71 sites in United States, China, Italy, Spain, India and 5 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 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.

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

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

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

Contact Juby Philip ((302) 559-4320, clinicaltrials@harmonybiosciences.com), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Percent Change in CMMS-28 (time frame: From Baseline Period up to 16 weeks). 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 NCT05066217.

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 9 Oct 2026.

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