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

August 19, 2026 updated by: Epygenix

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).

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

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.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
260

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 3

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • China
      • Beijing, China, 100045
        • Recruiting
        • Beijing Children's Hospital, Capital Medical University - PIN
        • Principal Investigator:
          • Hui Xiong
      • Beijing, China, 100034
        • Recruiting
        • Peking University First Hospital - Changqiao Campus
        • Principal Investigator:
          • Yuwu Jiang
      • Beijing, China, 100034
        • Recruiting
        • Peking University First Hospital - Daxing Campus
        • Principal Investigator:
          • Yuwu Jiang
      • Changchun, China, 130021
        • Recruiting
        • The First hospital of Jilin University
        • Principal Investigator:
          • Jianmin Liang
      • Changsha, China, 410007
        • Recruiting
        • Hunan Children's Hospital
        • Principal Investigator:
          • Sai Yang
      • Chengdu, China, 610041
        • Recruiting
        • West China Second University Hospital, Sichuan University - Huaxi Campus
        • Principal Investigator:
          • Rong Luo
      • Chengdu, China, 610073
        • Recruiting
        • Chengdu Women's and Children's Central Hospital
        • Principal Investigator:
          • Li Yan
      • Chongqing, China, 400014
        • Recruiting
        • Children's Hospital of Chongqing Medical University
        • Principal Investigator:
          • Li Jiang
      • Guangzhou, China, 510260
        • Recruiting
        • The Second Affiliated Hospital of Guangzhou Medical University
        • Principal Investigator:
          • Xiaorong Liu
      • Guiyang, China, 550004
        • Recruiting
        • The Affiliated Hospital of Guizhou Medical University
        • Principal Investigator:
          • Rong Ai
      • Jinan, China, 250012
        • Recruiting
        • Qilu Hospital of Shandong University
        • Principal Investigator:
          • Baomin Li
      • Nanchang, China, 330006
        • Recruiting
        • Jiangxi Provincial Children's Hospital
        • Principal Investigator:
          • Yong Chen
      • Shenzhen, China, 518000
        • Recruiting
        • Shenzhen Children's Hospital
        • Principal Investigator:
          • Dezhi Cao
      • Wuhan, China, 430015
        • Recruiting
        • Wuhan Children's Hospital
        • Principal Investigator:
          • Dan Sun
      • Xi'an, China, 710004
        • Recruiting
        • The Second Affiliated Hospital of Xi'an Jiaotong University
        • Principal Investigator:
          • Lin Yang
      • Xuzhou, China, 221006
        • Recruiting
        • Xuzhou Children's Hospital
        • Principal Investigator:
          • Xiaoming Liu
  • Italy
      • Catanzaro, Italy, 88100
        • Recruiting
        • Azienda Ospedaliera Universitaria Renato Dulbecco - AO Mater Domini
        • Principal Investigator:
          • Antonio Gambardella
      • Florence, Italy, 50139
        • Recruiting
        • Azienda Ospedaliero Universitaria A Meyer
        • Principal Investigator:
          • Renzo Guerrini
      • Milan, Italy, 20133
        • Recruiting
        • Fondazione IRCCS Istituto Neurologico Carlo Besta
        • Principal Investigator:
          • Giuseppe Didato
    • Molise
      • Pozzilli, Molise, Italy, 86077
        • Recruiting
        • IRCCS Istituto Neurologico Mediterraneo Neuromed
        • Principal Investigator:
          • Alfredo D'Aniello
  • Poland
    • Lesser Poland Voivodeship
      • Krakow, Lesser Poland Voivodeship, Poland, 30-363
        • Recruiting
        • Centrum Medyczne Plejady Magdalena Celinska
        • Principal Investigator:
          • Marta Zolnowska, MD
    • Masovian Voivodeship
      • Warsaw, Masovian Voivodeship, Poland, 02-829
        • Recruiting
        • Neurosphera
        • Principal Investigator:
          • Beata Zwolinska
  • Romania
      • Bucharest, Romania, 050098
        • Recruiting
        • Emergency University Hospital
        • Principal Investigator:
          • Ioana Raluca Mindruta
      • Bucharest, Romania, 041408
        • Recruiting
        • Centrul National Clinic De Recuperare Neuropsihomotorie Copii Robanescu-Padure
        • Principal Investigator:
          • Madalina Leanca
      • Iași, Romania, 700309
        • Recruiting
        • Sf. Maria Children Emergency Clinical Hospital Iasi
        • Principal Investigator:
          • Ioana Grigore
  • Serbia
      • Belgrade, Serbia, 11000
        • Recruiting
        • Mother and Child Health Care Institute of Serbia Dr Vukan Cupic
        • Principal Investigator:
          • Biljana Vucetic Tadic
      • Niš, Serbia, 18 000
        • Recruiting
        • University Clinical Center Nis
        • Principal Investigator:
          • Tatjana Tosic
      • Novi Sad, Serbia, 21000
        • Recruiting
        • Children and Youth Health Care Institute of Vojvodina
        • Principal Investigator:
          • Tatjana Redzek Mudrinic
  • Spain
      • Barcelona, Spain, 08025
        • Recruiting
        • Hospital De La Santa Creu I Sant Pau
        • Principal Investigator:
          • Alba Sierra-Marcos
      • Barcelona, Spain, 08035
        • Recruiting
        • Hospital Universitario Vall d'Hebron - PPDS
        • Principal Investigator:
          • Manuel Toledo Argany
      • Madrid, Spain, 28009
        • Recruiting
        • Hospital Infantil Universitario Niño Jesus - PIN
        • Principal Investigator:
          • Victor Soto Insuga
      • Málaga, Spain, 29010
        • Recruiting
        • Hospital Regional Universitario de Malaga - Hospital General
        • Principal Investigator:
          • Pedro Serrano
      • Pamplona, Spain, 31008
        • Recruiting
        • Hospital Universitario de Navarra
        • Principal Investigator:
          • Sergio Aguilera Albesa
      • Seville, Spain, 41013
        • Recruiting
        • Centro de Neurologia Avanzada
        • Principal Investigator:
          • Juan Jesús Rodríguez Uranga, MD
  • United States
    • Arkansas
      • Little Rock, Arkansas, United States, 72202
        • Active, not recruiting
        • Arkansas Children's Hospital
    • California
      • Orange, California, United States, 92868
        • Active, not recruiting
        • UC Irvine Medical Center
    • Florida
      • Miami, Florida, United States, 33136
        • Recruiting
        • University of Miami Miller School of Medicine
        • Principal Investigator:
          • Kamil Detyniecki, MD
        • Contact:
      • Orlando, Florida, United States, 32804
        • Recruiting
        • AdventHealth Innovation Tower
        • Principal Investigator:
          • Holly Skinner, DO
      • Orlando, Florida, United States, 34746
        • Suspended
        • Rare Disease Research
      • Winter Park, Florida, United States, 32789
        • Active, not recruiting
        • Pediatric Neurology and Epilepsy Specialists
    • Illinois
      • Chicago, Illinois, United States, 60611
        • Recruiting
        • Re:Cognition Health
        • Contact:
        • Principal Investigator:
          • Antonio Iglesias, MD
    • Kentucky
      • Louisville, Kentucky, United States, 40202
        • Recruiting
        • Norton Children's Medical Center
        • Contact:
        • Principal Investigator:
          • Jaime Shoup, MD
    • Michigan
      • Detroit, Michigan, United States, 48202
        • Active, not recruiting
        • Henry Ford Hospital
    • Minnesota
      • Roseville, Minnesota, United States, 55102
        • Recruiting
        • Minnesota Epilepsy Group, P.A.
        • Contact:
        • Principal Investigator:
          • Stephanie Ahrens, MD
    • Nebraska
      • Omaha, Nebraska, United States, 68114
        • Recruiting
        • Children's Nebraska
        • Contact:
        • Principal Investigator:
          • Sookyong Koh
    • New Jersey
      • Marlboro, New Jersey, United States, 07746
        • Recruiting
        • Tekton Research
        • Principal Investigator:
          • Amor Mehta, MD
        • Contact:
    • New York
      • New York, New York, United States, 10021
      • New York, New York, United States, 10016-4852
        • Recruiting
        • NYU Comprehensive Epilepsy Center - BRANY - PPDS
        • Principal Investigator:
          • Dana Price
    • North Carolina
      • Charlotte, North Carolina, United States, 28211
        • Recruiting
        • On-Site Clinical Solution
        • Contact:
        • Principal Investigator:
          • Robert Nahouraii
      • Charlotte, North Carolina, United States, 28207
      • Durham, North Carolina, United States, 27705
        • Recruiting
        • Duke University Medical Center
        • Contact:
        • Principal Investigator:
          • Muhammad Zafar, MD
      • Morrisville, North Carolina, United States, 27560
        • Recruiting
        • PPD Virtual-Science 37, Inc.
        • Principal Investigator:
          • Antonio Iglesias, MD
        • Contact:
    • Pennsylvania
      • Philadelphia, Pennsylvania, United States, 19104
        • Recruiting
        • Children's Hospital of Philadelphia
        • Principal Investigator:
          • Eric Marsh, MD
    • Texas
      • Houston, Texas, United States, 77030
        • Recruiting
        • UTHealth Houston
        • Contact:
        • Principal Investigator:
          • Mary Koenig, MD
    • Utah
      • Salt Lake City, Utah, United States, 84132
        • Recruiting
        • Clinical Neurosciences Center
        • Principal Investigator:
          • Angela Peters, MD

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

14 years and older (Child, Adult)

Accepts Healthy Volunteers

No

Description

Key Inclusion Criteria:

  1. Males or females, ages ≥2 to ≤55 years, at the time of Screening.
  2. Participant/parent/legal authorized representative (LAR) willing and able to give written informed consent/assent.

  3. 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.

Key Exclusion Criteria:

  1. Known sensitivity, allergy, or previous exposure to clemizole HCl.
  2. 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).
  3. Family history of sudden cardiac death, unexplained death, or death from a primary dysrhythmia potentially associated with QT prolongation in any family member.
  4. 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.
  5. Epilepsy surgery planned during the study or epilepsy surgery within 6 months prior to Screening.
  6. Concomitant use of fenfluramine.
  7. Prior or concomitant use of lorcaserin.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Placebo Comparator: Placebo
Participants will receive their first dose of study drug following randomization.
Drug: Placebo
Placebo will be administered as an oral solution.
Experimental: Double-blind clemizole HCl
Participants will receive their first dose of study drug following randomization.
Drug: Clemizole HCl
Clemizole HCl will be administered as an oral solution.
Other Names:
  • EPX-100
Experimental: Open-label clemizole HCl
Eligible 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.
Drug: Clemizole HCl
Clemizole HCl will be administered as an oral solution.
Other Names:
  • EPX-100

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Percent Change in CMMS-28
Time Frame: From Baseline Period up to 16 weeks
Percent change in CMMS-28 from the Baseline Period through the end of the DB Period
From Baseline Period up to 16 weeks

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Proportion of Participants with ≥50% Reduction in CMMS-28
Time Frame: From Baseline Period up to 16 weeks
Proportion of participants with ≥50% reduction in CMMS-28 from the Baseline Period through the end of the DB Period
From Baseline Period up to 16 weeks
Percent Change in CMMS-28 Seizure-free Days
Time Frame: From Baseline Period up to 16 weeks
Percent change in CMMS-28 seizure-free days from the Baseline Period through the end of the DB Period
From Baseline Period up to 16 weeks
Clinical Global Impression of Change (CGI-C) Score
Time Frame: Week 16
CGI-C score at the end of the DB Period
Week 16
Caregiver Global Impression of Change (CaGI-C) Score
Time Frame: Week 16
CaGI-C score at the end of the DB Period
Week 16
Caregiver Global Impression of Change in Seizure Intensity/Duration (CaGI-CSID) Score
Time Frame: Week 16
CaGI-CSID score at the end of the DB Period
Week 16
Change in Quality of Life Inventory (QI)-Disability Score
Time Frame: From Baseline Period up to 16 weeks
Change in QI-disability score from Baseline to the end of the DB Period
From Baseline Period up to 16 weeks
Percent Change per 28 Days in the Number of Seizure Free Days
Time Frame: From Baseline Period up to 16 weeks
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
From Baseline Period up to 16 weeks
Percent Change in CMMS-28
Time Frame: From Baseline Period up to 12 weeks
Percent change in CMMS-28 from the Baseline Period through the end of the DB Maintenance Phase only
From Baseline Period up to 12 weeks
Proportion of Participants with ≥50% Reduction in CMMS-28
Time Frame: From Baseline Period up to 12 weeks
Proportion of participants with ≥50% reduction in CMMS-28 from the Baseline Period through the end of the DB Maintenance Phase only
From Baseline Period up to 12 weeks
Incidence of Treatment-Emergent Adverse Events (TEAEs)
Time Frame: From the first dose administration of study drug up to end of the study, approximately up to 172 weeks
Incidence of TEAEs will be compared among the treatment groups
From the first dose administration of study drug up to end of the study, approximately up to 172 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Epygenix

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Harmony Biosciences Management, Inc.

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Director: Amit Ray, MD, Harmony Biosciences Management, Inc.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
April 9, 2025

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
November 1, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
November 1, 2029

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
September 23, 2021

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 23, 2021

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
October 4, 2021

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
August 21, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 19, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
August 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • EPX-100-003

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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