PLYMOUTH MEETING, Pa. / Dec 02, 2025 / Business Wire / Harmony Biosciences Holdings, Inc. (Nasdaq: HRMY), today announced that it will highlight new open-label extension data from the company’s investigation of EPX-100 (clemizole hydrochloride) in the ongoing Phase 3 ARGUS trial for the treatment of Dravet syndrome at the 2025 American Epilepsy Society (AES) Annual Meeting being held December 5 – December 9, 2025, in Atlanta, GA.

The ARGUS trial is currently enrolling, and more information can be found at argustrial.com.

The posters will be on display on Monday, December 8, from 8:00 am - 2:00 pm ET. Poster presentation details are listed below:

About Clemizole Hydrochloride (EPX-100)

EPX-100, clemizole hydrochloride, is an investigational product under development for the treatment of Dravet syndrome (DS) and Lennox-Gastaut syndrome (LGS). EPX-100 acts by targeting central 5-hydroxytryptamine 2 (5HT-2) receptors to modulate serotonin signaling. EPX-100 is administered orally twice a day in a liquid formulation and has been developed based on a proprietary phenotype-based zebrafish drug screening platform. These scn1Lab mutant zebrafish replicate the genetic etiology and phenotype observed in the majority of individuals with DS. The scn1Lab mutant zebrafish model that expresses voltage gated sodium channels has been used for high-throughput screening of compounds that modulate Nav1.1 in the central nervous system.

About Dravet Syndrome

Dravet syndrome (DS) is a severe and progressive developmental epileptic encephalopathy that causes significant impact on patient functioning. DS begins in the first year of life and is characterized by high seizure frequency and severity, intellectual disability, and an increased risk of sudden unexpected death in epilepsy (SUDEP). Approximately 85% of Dravet syndrome cases are caused by de novo loss-of-function (LOF) mutations in a voltage-gated sodium channel gene, SCN1A. DS has an estimated incidence rate of 1:15,700 in the US.

About Harmony Biosciences

Harmony Biosciences is a pharmaceutical company dedicated to developing and commercializing innovative therapies for patients with rare neurological diseases who have unmet medical needs. Driven by novel science, visionary thinking, and a commitment to those who feel overlooked, Harmony Biosciences is nurturing a future full of therapeutic possibilities that may enable patients with rare neurological diseases to truly thrive. Established by Paragon Biosciences, LLC, in 2017 and headquartered in Plymouth Meeting, Pa., we believe that when empathy and innovation meet, a better future can begin; a vision evident in the therapeutic innovations we advance, the culture we cultivate, and the community programs we foster. For more information, please visit www.harmonybiosciences.com.