Harmony Biosciences has agreed to acquire Epygenix Therapeutics and its pipeline of serotonin agonist candidates for rare epileptic disorders, including the pivotal-stage asset EPX-100, in a deal that could be worth up to $680 million."This acquisition builds on our leadership in sleep/wake and neurobehavioural disorders," said Harmony CEO Jeffrey Dayno in a statement Tuesday. Harmony's sole product on the market is Wakix (pitolisant), which was approved in 2019 as a treatment for patients withNarcolepsy, and last year it bought out Zynerba Pharmaceuticals for up to $200 million, gaining a non-euphoric cannabinoid for rare neuropsychiatric disorders such as fragile X syndrome.Dravet readout in 2026The latest the deal "gives us three distinct CNS (central nervous system) franchises in late-stage development, each with a potential US peak sales opportunity of $1 billion - $2 billion," Dayno estimates. It includes a modest $35 million upfront, but could see an additional $130 million in future development and regulatory milestone payments as well as up to $515 million if certain sales targets are met.Epygenix's lead product is EPX-100 (clemizole), a serotonin 5HT2 receptor agonist currently in a registrational Phase II trial as a potential add-on treatment to help control convulsive seizures in paediatric and adult patients with Dravet syndrome. Top-line data are expected in 2026.LGS late-stage trial on deckHarmony also plans to start a Phase III trial of EPX-100 in Lennox-Gastaut syndrome (LGS) in the second half. "The proven mechanism of action of clemizole could potentially offer an improved product profile over currently available treatment options and improve daily functioning" in both Dravet and LGS patients, Harmony said.Epygenix's second investigational compound is EPX-200, an oral 5HT2C agonist that has received orphan drug designations for Dravet and LGS as well. According to the company's website, EPX-200 is an "FDA-approved weight management drug" modulates 5HT signaling pathways and reduced convulsive seizure frequency and/or severity in people with Dravet syndrome in a small-scale clinical trial.Both drugs, along with another early-stage compound EPX-300, are also in early testing for developmental epileptic encephalopathies. EPX-300 is an "FDA-approved antidepressant, anti-anxiety and sleep-inducing insomnia drug" that also targets 5HT signaling, the company wensite says.
