ClinicalTrials.gov record NCT04462770

A Study of EPX-100 (Clemizole Hydrochloride) in Participants With Dravet Syndrome

Record copied from ClinicalTrials.gov: Oct 10, 2026AI summaries generated: Aug 25, 2026

A 20-Week Multicenter, Randomized, Double-Blind, Placebo-Controlled Trial of EPX-100 (Clemizole Hydrochloride) as Adjunctive Therapy in Children and Adult Participants With Dravet Syndrome (ARGUS Trial)

StatusRecruitingThe study is currently enrolling participants. Only the study team can say whether a particular person can join.
Study typeInterventionalA study in which researchers assign participants to one or more interventions, such as a drug, procedure, device, behavioural programme or other approach, to measure their effects.
PhasePhase 3A later-stage study, usually with more participants, designed to give stronger evidence about how well a treatment works and how safe it is. It often compares the treatment with standard care or a placebo, and results may support an application for approval.
Age2 years old and older
SexAll
LocationArgentina, Brazil, Canada, Georgia, Hungary, India, Poland, Spain, United Kingdom, United States
AI summaryWhat this study is about, in plain languageShow ▾Hide ▴

AI-written from the registry record, not the study's own wording. May contain errors or omissions. Check the registry text on this page and the original record ↗ before acting on it.

This Phase 3 trial evaluates clemizole hydrochloride (EPX-100) added to standard anti-seizure medicines in children and people with Dravet syndrome. After a 4-week observational baseline, participants are randomized for 16 weeks to receive EPX‑100 or placebo in a triple-masked, parallel design. Those who finish the double-blind period may continue in an open-label extension to receive clemizole for up to 3 years.

What it is studying. The study is testing whether adding clemizole hydrochloride (EPX-100) to a participant's existing anti-seizure medicines changes the frequency of countable motor seizures and to record the drug's safety and side-effect profile.

What the researchers hope to learn. Scientifically, the trial aims to evaluate clemizole hydrochloride (EPX-100) as adjunctive therapy in Dravet syndrome by measuring changes in countable motor seizures per 28 days, the proportion of participants with ≥50% seizure reduction, number of seizure-free days, clinician and caregiver global impression scores, changes in all seizures and rescue anti-epileptic drug use, and the incidence of treatment-emergent adverse events.

What this study is about

The study's own summary, as published on ClinicalTrials.gov. Underlined terms have a short explanation.

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

Interventions being studied

Being studied in this trial does not mean the treatment or procedure is approved or available for this condition.

Drug
  • Clemizole HCl
  • Placebo

Eligibility

The criteria exactly as listed on ClinicalTrials.gov. Only the study team can say whether they apply to you.

Inclusion criteria

  • Male and female participants 2 years and older at time of consent.
  • Participant or parent/legally authorized representative (LAR) willing and able to provide written informed consent and assent (if applicable) prior to initiation of any study related procedures.
  • Clinical diagnosis of DS. Participants must have seizures which are not completely controlled by AEDs with the following criteria:
  • Onset of seizures prior to 18 months of age,
  • Normal development at onset,
  • History of at least one type of countable motor seizure (CMS),
  • Brain MRI without cortical malformation (not including mild atrophy associated with the natural progression of DS),
  • Genetic mutation of the SCN1A gene must be documented.
  • Key

Exclusion criteria

  • Known sensitivity, allergy, or previous exposure to clemizole HCl.
  • Exposure to any investigational drug or device <90 days prior to screening or plans to participate in another drug or device trial at any time during the study.
  • Seizures secondary to illicit drug (this includes concomitant use of tetrahydrocannabinol [THC] and nonprescription cannabidiol preparations) or alcohol use, infection, neoplasm, demyelinating disease, degenerative neurological disease, or central nervous system disease deemed progressive, metabolic illness, or progressive degenerative disease.
  • Concurrent use of lorcaserin. Note: Prior use of lorcaserin is permitted if at least 30 days have passed since the last dose.
  • Concurrent use of fenfluramine.
  • Epilepsy surgery planned during the study or epilepsy surgery within 6 months prior to Screening.

Study description and what participation involves

The study's detailed description, as published on ClinicalTrials.gov.

Detailed description from the registry

This is a global, multicenter, randomized, double-blind, placebo-controlled study to evaluate the safety and efficacy of clemizole hydrochloride as adjunctive therapy in children and adult participants with DS. The study consists of a 4-week Observational Period, a 16-week Double-Blind (DB) Period and an Open-Label Extension (OLE) Period.

AI summaryWhat participation may involve, in plain languageShow ▾Hide ▴

AI-written from the registry record, not the study's own wording. May contain errors or omissions. Check the registry text on this page and the original record ↗ before acting on it.

Participants begin with a 4-week observational (baseline) period, then enter a 16-week double-blind period and are randomly assigned to receive either clemizole HCl oral solution or placebo. Those who complete the double-blind period may choose to join an open‑label extension and receive clemizole HCl for up to 3 years. During the study participants will take the study medicine by mouth, have their countable motor seizures tracked, and clinicians will complete brief global-impression ratings of change. The registry record does not list any especially invasive procedures (for example, lumbar puncture or bone‑marrow biopsy).

How the study is structured. This is a randomized, triple-masked (participants, caregivers, and study staff blinded), placebo-controlled, parallel-group Phase 3 drug trial. It includes a 4-week observational baseline, a 16-week double-blind period where participants receive either oral clemizole solution or matching oral placebo, and an optional open-label extension during which eligible participants may receive clemizole for up to 3 years.

Questions you could ask

These questions are suggestions for a conversation with the study team or your own clinician, not advice.

  • The registry lists this study under Dravet Syndrome. Does it apply to my diagnosis?
  • Some participants receive a placebo. How is that decided, and what happens for placebo-group participants when the study ends?
  • The listed sites are in Argentina, Brazil, Canada, Georgia, Hungary, India, Poland, Spain, United Kingdom, United States. Is any of them reachable for me, and does the study help with travel?
  • Which of the eligibility criteria would need to be checked with tests before I could join?

More on CDKL5 deficiency disorder

This trial is also listed on this site under Dravet syndrome.

Clinical trials22 trials listed for CDKL5 deficiency disorderEvery trial the registry lists for CDKL5 deficiency disorder, with recruitment status, phase and sites, updated from ClinicalTrials.gov.See all trials →Research updatesWhat changed in CDKL5 deficiency disorder researchLatest monthly update: September 2026. Includes: EEG background changes. New research summarized each month in plain language, with links to every source paper.Read the latest update →

Important dates

Study start
Sep 15, 2020
Primary completion
April 2027 (estimated)
Study completion
May 2029 (estimated)
Target enrollment
150 participants (estimated)
Last updated on registry
Sep 15, 2026
Data verified
Oct 10, 2026

Sponsor and research team

The lead sponsor funds and oversees the trial. A pharmaceutical or biotech company sponsor typically means the study is testing that company's drug or device; a hospital, university, or government agency usually indicates investigator-initiated or publicly funded research.

Lead sponsor
Epygenix
Collaborators
  • Harmony Biosciences Management, Inc.

Central study contact

If you're interested in participating, the central contact can answer general questions about the study — including eligibility requirements and how to find a recruiting site near you. Actual eligibility is determined by the site's medical team.

Participating sites (68)

  • University of Alabama at BirminghamRecruiting

    Birmingham, Alabama, 35233 · United States

  • Arkansas Children's HospitalRecruiting

    Little Rock, Arkansas, 72202 · United States

  • Children's Hospital of Los AngelesTerminated

    Los Angeles, California, 90027 · United States

  • University of California IrvineRecruiting

    Orange, California, 92868 · United States

  • UCSF Medical CenterTerminated

    San Francisco, California, 94158 · United States

  • Yale School of Medicine - Yale-New Haven HospitalRecruiting

    New Haven, Connecticut, 06511 · United States

    • Aline Herlopian, MD
  • The Nemours FoundationTerminated

    Wilmington, Delaware, 19803 · United States

  • Rare Disease Research FLTerminated

    Kissimmee, Florida, 34746 · United States

  • Pediatric Neurology and Epilepsy SpecialistsRecruiting

    Winter Park, Florida, 32789 · United States

  • Clinical Integrative Research Center of Atlanta (CIRCA)Withdrawn

    Atlanta, Georgia, 30328 · United States

Terms used on this page · explanations by MedicalUpdates.ai

randomized
Participants are assigned to the study groups by chance, like a coin toss, rather than chosen by the doctor or the participant. This is done so the groups are comparable.
double-blind
Two types of people involved in the study do not know which intervention a participant is receiving. The ClinicalTrials.gov record specifies who is masked, for example participants, care providers, investigators or outcome assessors.
placebo-controlled
A study design in which one group receives a placebo so that the study treatment's effects can be compared with no active treatment.
legally authorized representative
A person who is legally allowed to make decisions, including consent to research, on behalf of someone who cannot consent for themselves.
written informed consent
The process of explaining a study, including its risks and what participation involves, so that a person can decide freely whether to take part. Consent is usually documented in writing, and a participant can choose to leave the study later.
assent
A child's or dependent adult's agreement to take part, given alongside the formal consent of a parent or legal representative.
MRI
A scan that uses magnets and radio waves, not X-rays, to make detailed pictures of the inside of the body. Some implants and metal objects mean a person cannot have one.
investigational drug
A treatment that is being tested and has not been approved for this use. It may be approved for a different condition. Being studied does not mean it works or is available outside the study.
prior to screening
The checks done before enrolment to see whether a person qualifies, such as tests, scans or a review of medical history.
Key Inclusion Criteria
The conditions a person must meet to be considered for the study, for example a confirmed diagnosis, an age range or a test result.
Key Exclusion Criteria
The conditions that rule a person out even if they meet the inclusion criteria, for example other illnesses, certain medicines or pregnancy.
Observational
A study in which researchers do not assign participants to a treatment or other intervention. They observe or measure what happens, which may include study visits, tests, questionnaires or a review of medical records.
Open-Label Extension
A continuation study in which participants who completed an earlier study can keep receiving the treatment, usually with everyone knowing what they are given.

The study record on this page is reproduced from ClinicalTrials.gov, a database of the U.S. National Library of Medicine, where it was submitted by the study sponsor. MedicalUpdates.ai does not own this content, is not affiliated with or endorsed by ClinicalTrials.gov, NIH, or the U.S. Government, and does not verify the record. Plain-language notes, the glossary and the questions above are added by this site; text in the boxes marked "AI summary" was written by an AI model and may contain errors. Registry records change over time. Check the original record for the current version and discuss eligibility or participation with a qualified healthcare professional.

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