PLYMOUTH MEETING, PA — Harmony Biosciences Holdings, Inc. (Nasdaq: HRMY) reported new late-stage clinical data showing its experimental epilepsy drug EPX-100 delivered sharp and sustained seizure reductions in patients with Dravet syndrome, reinforcing the company’s push to expand its neurology pipeline.
The company said initial open-label extension data from its Phase 3 ARGUS trial showed a median reduction of about 50 percent in countable motor seizures over 28 days among patients who received EPX-100 for at least six months. Half of those participants achieved seizure reductions of 50 percent or more, a benchmark often used to gauge meaningful clinical benefit in epilepsy studies.
The findings will be presented Monday, December 8, at the American Epilepsy Society Annual Meeting in Atlanta. They come as Harmony prepares for a topline data readout from the ARGUS trial in 2026, a potential inflection point for the company’s epilepsy franchise.
EPX-100, also known as clemizole hydrochloride, was generally well tolerated in patients treated for more than two years, with some approaching three years of exposure. The most common adverse events were seizures, fever, and upper respiratory infections. Harmony said there were no significant gastrointestinal side effects and no need for additional laboratory monitoring, factors that could differentiate the therapy in a crowded and demanding treatment landscape.
Chief Medical and Scientific Officer Kumar Budur said the data are especially notable given the severity of Dravet syndrome, a rare and life-threatening childhood epilepsy marked by frequent seizures and limited treatment options. He said the results support continued development of EPX-100 as Harmony advances toward its next major clinical milestone.
EPX-100 targets serotonin signaling through 5-HT2 receptors and is administered orally twice a day in liquid form. The drug is also being tested in Lennox-Gastaut syndrome, another severe and drug-resistant epilepsy, in the Phase 3 LIGHTHOUSE trial. Both studies are global, randomized, and placebo-controlled.
For investors, the update highlights Harmony’s strategy to build beyond its existing commercial portfolio by developing therapies for rare neurological disorders with high unmet medical need. Positive late-stage data could position EPX-100 as a future growth driver if regulatory approvals follow.
For the latest news on everything happening in Chester County and the surrounding area, be sure to follow MyChesCo on Google News and MSN.