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Harmony Biosciences to Present New Open-Label Extension Data from Phase 3 ARGUS Trial at the 2025 American Epilepsy Society Annual Meeting

Key Takeaway: Harmony Biosciences will present new open-label extension data from its Phase 3 ARGUS trial for EPX-100 at the 2025 American Epilepsy Society Annual Meeting. The trial focuses on the treatment of Dravet syndrome, a severe form of epilepsy. The presentation is scheduled for December 8, 2025, in Atlanta, GA.
Price reaction · baseline $35.51 (2025-12-01 close) · hit pre-market · clean, no other HRMY news in the window
day 0 close · peak
+1.4%

Market Sentiment Analysis

POSITIVE FACTORS

  • New data from the Phase 3 ARGUS trial is being presented.
  • EPX-100 shows promise for treating Dravet syndrome.
  • Harmony Biosciences is committed to addressing unmet medical needs.

BiopharmaWatch Analysis

From our catalyst data and publicly available data · not financial advice
Best trade, last catalyst
+43%
120-day peak, hindsight
Typical move
3.4%
average across 4 past catalysts
Lead asset
Clemizole
Phase 3 · Lennox Gastaut Syndrome

Full Press Release Details

PLYMOUTH MEETING, Pa.--(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 atargustrial.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:
Abstract Title: EPX-100 as Adjunctive Therapy in Patients With DravetSyndrome: Preliminary Results From the Open-Label Extension Phase of the ARGUS Study
Poster #: 3.353
Presentation: Monday, December 8, from 12:00 pm – 1:45 pm ET
Abstract Title: A Drug-Drug Interaction Study of EPX-100 (Clemizole Hydrochloride) With Clinical Probe Substrates for Selected CYP Enzymes
Poster #: 3.359
Presentation: Monday, December 8, from 12:00 pm – 1:45 pm ET
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. Thesescn1Labmutant zebrafish replicate the genetic etiology and phenotype observed in the majority of individuals with DS. Thescn1Labmutant 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 SyndromeDravet 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 BiosciencesHarmony 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 visitwww.harmonybiosciences.com.

Frequently Asked Questions

What is the focus of the Phase 3 ARGUS trial?

The Phase 3 ARGUS trial investigates EPX-100 for treating Dravet syndrome.

When will the new data be presented?

The new data will be presented on December 8, 2025.

What is EPX-100?

EPX-100, or clemizole hydrochloride, is an investigational treatment for Dravet syndrome.

Where will the AES Annual Meeting be held?

The AES Annual Meeting will take place in Atlanta, GA.

Last updated: Dec 2, 2025