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Evaluating clemizole hydrochloride for treating Dravet syndrome

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)

Phase 3 Interventional Epygenix · NCT04462770

This study is testing if clemizole hydrochloride can help children and adults with Dravet syndrome who still have seizures despite taking other medications.

Quick facts

PhasePhase 3
Study typeInterventional
Enrollment150 (estimated)
Ages2 Years and up
SexAll
SponsorEpygenix Industry-sponsored
Locations46 sites (Los Angeles, California and 45 other locations)
Trial IDNCT04462770 on ClinicalTrials.gov

What this trial studies

This multicenter, Phase 3, randomized, double-blind, placebo-controlled study aims to assess the safety and efficacy of clemizole hydrochloride (EPX-100) as an adjunctive therapy for individuals with Dravet syndrome. Participants will undergo a 4-week observational period followed by a 16-week double-blind phase, and an open-label extension lasting up to 156 weeks. The study includes both children and adults who experience seizures that are not fully controlled by existing antiepileptic drugs.

Who should consider this trial

Good fit: Ideal candidates are males and females aged 2 years and older with a clinical diagnosis of Dravet syndrome and documented SCN1A gene mutation.

Not a fit: Patients with known sensitivity or allergy to clemizole hydrochloride or those who have participated in another investigational drug study within the last 90 days may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could significantly reduce the frequency of seizures in patients with Dravet syndrome.

How similar studies have performed: Other studies have shown promise in using adjunctive therapies for Dravet syndrome, but the specific use of clemizole hydrochloride is novel.

Eligibility criteria

Show full inclusion / exclusion criteria 
Key Inclusion Criteria:

1. Male and female participants 2 years and older at time of consent.
2. Participant or parent/legally authorized representative (LAR) willing and able to provide written informed consent, assent (if applicable) prior to initiation of any study related procedures.
3. 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:

1. Known sensitivity, allergy, or previous exposure to clemizole HCl.
2. 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.
3. 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.
4. Concurrent use of lorcaserin. Note: Prior use of lorcaserin is permitted if at least 30 days have passed since the last dose.
5. Concurrent use of fenfluramine.
6. Epilepsy surgery planned during the study or epilepsy surgery within 6 months prior to Screening.

Where this trial is running

Los Angeles, California and 45 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Dravet SyndromeClemizole hydrochlorideConvulsive seizurePediatric epilepsyDravet syndrome
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.