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

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.

Key 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.