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Updated May 2026 · ClinicalTrials.gov

RECRUITINGPhase 3INTERVENTIONAL

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

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

An Efficacy and Safety Study of Clemizole HCl in Patients With Lennox-Gastaut Syndrome (NCT05066217) is a Phase 3 interventional studying Lennox Gastaut Syndrome, sponsored by Epygenix. RECRUITING as of the most recent ClinicalTrials.gov update. Talk to your doctor before contacting the trial site.

Important: This information is not medical advice. Talk to your doctor about whether a clinical trial is right for you.

About This Trial

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).

What Stage of Research Is This?

Phase 3 trials confirm efficacy and safety in large patient groups (often 300–3,000+) and form the evidence base for an FDA approval submission. For Lennox Gastaut Syndrome, Phase 3 studies typically randomize participants between the investigational treatment and either a placebo or current standard of care. A successful Phase 3 result is the threshold most treatments need to clear before regulatory approval.

This trial is currently recruiting participants. The sponsor has registered the study with ClinicalTrials.gov as actively enrolling, which means new applicants who meet the eligibility criteria can be considered for screening. Trial status can change between updates — confirm current recruiting status with the study contact before traveling for a screening visit.

Target enrollment of 260 participants puts this in the typical range for a Phase 2-style efficacy study or a moderate Phase 3 trial in a focused Lennox Gastaut Syndrome subpopulation. At this scale, the study has enough statistical power to detect a clear treatment effect but is not the largest cohort in the field.

Who May Be Eligible (Plain English)

Key Who May Qualify: 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 willing to sign a consent form/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 Who Should NOT Join This Trial: 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. Always talk to your doctor about whether this trial is right for you.

These are translations of the protocol\'s inclusion and exclusion criteria, simplified for patients and caregivers. The original clinical text appears below. Eligibility is ultimately confirmed by the trial site\'s screening process — this summary is a starting point for a conversation with your doctor, not a final determination.

Original Eligibility Criteria

View original clinical language
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.

Treatments Being Tested

DRUG

Clemizole HCl

Clemizole HCl will be administered as an oral solution.

DRUG

Placebo

Placebo will be administered as an oral solution.

Locations (20)

Trial sites listed on ClinicalTrials.gov for this study. Site activation status can vary — confirm with the specific site before traveling for a screening visit.

Arkansas Children's Hospital
Little Rock, Arkansas, United States
UC Irvine Medical Center
Orange, California, United States
UCI Center for Innovative Health Therapies
Orange, California, United States
Nemours Children's Health
Wilmington, Delaware, United States
Rare Disease Research
Kissimmee, Florida, United States
University of Miami Miller School of Medicine
Miami, Florida, United States
Pediatric Neurology and Epilepsy Specialists
Winter Park, Florida, United States
Re:Cognition Health
Chicago, Illinois, United States
Norton Children's Medical Center
Louisville, Kentucky, United States
Henry Ford Hospital
Detroit, Michigan, United States
Minnesota Epilepsy Group, P.A.
Roseville, Minnesota, United States
Children's Nebraska
Omaha, Nebraska, United States
Neurology Center for Epilepsy and Seizures
Marlboro, New Jersey, United States
Tekton Research
Marlboro, New Jersey, United States
Weill Cornell Medicine/New York Presbyterian Hospital
New York, New York, United States
Atrium Health STRIVE Research
Charlotte, North Carolina, United States
On-Site Clinical Solution
Charlotte, North Carolina, United States
Duke University Medical Center
Durham, North Carolina, United States
PPD Virtual-Science 37, Inc.
Morrisville, North Carolina, United States
UTHealth Houston
Houston, Texas, United States

How to Talk to Your Doctor About This Trial

Bring the printable summary of this trial — including the NCT ID (NCT05066217), the sponsor (Epygenix), and the key eligibility criteria — to your next appointment. Your doctor can review the inclusion and exclusion criteria against your medical history, lab values, and current treatments to assess whether you are likely to qualify. They can also help you weigh whether trial participation makes sense alongside your existing care plan.

Useful questions to walk through together: What does the trial protocol require beyond standard care? How long is the active treatment phase, and how long is follow-up? Are there study visits at sites I can reach? Who pays for the trial-specific procedures, and who pays for standard-of-care portions? See our 25 questions to ask about clinical trials guide for a more complete checklist.

Authoritative Sources

The official record for this trial lives on ClinicalTrials.gov — the federal registry maintained by the National Library of Medicine at NIH. For background on how this trial fits into the FDA approval pathway, see the FDA drug approval process. For oncology-specific guidance for patients considering trials, the National Cancer Institute publishes patient-oriented overviews. International trial registries are aggregated by the WHO ICTRP.

Frequently Asked Questions

What is the NCT05066217 clinical trial studying?

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). The full protocol is registered on ClinicalTrials.gov and includes the primary outcome measures, eligibility criteria, and study endpoints.

Who can participate in NCT05066217?

Eligibility for this trial depends on the specific inclusion and exclusion criteria set by the sponsor. The plain-English summary above translates the most important criteria into accessible language; the official clinical text is preserved in the collapsible section underneath. Whether you fit any specific trial is a medical decision your doctor needs to confirm — bring the trial information to your treating physician for a full review against your medical history.

How do I contact the trial site for NCT05066217?

Contact information registered with ClinicalTrials.gov is shown in the sidebar of this page. Before reaching out, confirm with your treating physician that this trial is appropriate for your situation. The trial site will then walk you through the screening process to determine final eligibility.

Is participating in a clinical trial safe?

Clinical trials in the United States are regulated by the FDA and overseen by Institutional Review Boards (IRBs) that review the protocol for safety. Risk varies by trial — Phase 1 studies test new treatments in humans for the first time, while Phase 3 trials use treatments that have already passed earlier safety screening. The informed consent document for any specific trial details the known risks and what to expect. Discuss those risks with your physician before deciding whether to participate.

Where can I verify the data on this page?

Every detail on this page comes directly from the ClinicalTrials.gov API. Click "View on ClinicalTrials.gov" in the sidebar to see the official, unmodified record. The federal record is always authoritative; this page is a structured presentation with a plain-English eligibility translation. For background on how clinical trials are regulated, see the FDA drug approval process documentation.

How This Page Is Built

Every field on this page is pulled directly from the ClinicalTrials.gov API v2 — no estimates, no proxies. The plain-English eligibility translation is generated from the original protocol text and reviewed for fidelity to the underlying clinical criteria. The original clinical text remains visible in the collapsible section above so users and clinicians can verify the translation. Read the full methodology for the data pipeline and known limitations.

Source: ClinicalTrials.gov API v2 record for NCT05066217. Maintained by the National Library of Medicine at NIH. Public domain. Cite as: "TrialFinderData. NCT05066217. Data: ClinicalTrials.gov."

Medical disclaimer: This page is informational, not medical advice. Talk to your doctor about whether a clinical trial is right for you.

Last updated 2026-05-08 · Data from ClinicalTrials.gov.