Harmony Biosciences added a potential epilepsy treatment to its new drug candidate pipeline Tuesday with the acquisition of a North Jersey biopharmaceutical company.

Plymouth Meeting-based Harmony (NASDAQ: HRMY) is paying $35 million upfront for Epygenix Therapeutics of Paramus, New Jersey. The agreement also includes potential milestone payments of up to $645 million, with up to $130 million based on development and regulatory milestones, and up to $515 million tied to undisclosed sales targets being achieved.

Shares of Harmony were up 10% in mid-afternoon trading to $32.14. The stock finished the day up 6% at $30.91 per share.

Epygenix’s lead new drug candidate, EPX-100, is in late-stage clinical testing as a potential treatment for two rare types of epilepsy: Dravet Syndrome, which occurs in the first year of life, and Lennox-Gastaut Syndrome, which typically begins during childhood.

EPX-100 holds both orphan drug and rare pediatric disease designations, which provide companies with incentives to develop drug targeting conditions that afflict small patient populations, from the Food and Drug Administration.

Dr. Jeffrey M. Dayno, CEO of Harmony, said the deal for Epygenix gives his Harmony three distinct central nervous system franchises in late-stage development, each with potential peak sale opportunities of $1 billion to $2 billion in the U.S.

Harmony already markets the narcolepsy drug Wakix, a product that generated sales of $582 million in 2023, up 33% from the previous year. Wakix, which produced revenue of $154.6 million during the first quarter of this year, was approved by the FDA in 2019 as a treatment for excessive daytime sleepiness in adults with narcolepsy.

Harmony projects product sales of between $700 million and $720 million this year. The company said Tuesday it intends during the second half of 2024 to seek expanded approval for Wakix as a treatment for idiopathic hypersomnia, a sleep disorder in which a person is excessively sleepy during the day and has trouble waking up from sleep.

Earlier this month, Harmony entered into an exclusive licensing deal, valued at up to $393 million, for the U.S. and Latin American rights to Bioprojet's new drug candidate TPM-1116, a potential narcolepsy therapy. Under the terms of the deal, Harmony is paying Bioprojet of France $25.5 million upfront and up to $127.5 million if product development and regulatory milestones are met plus up to $240 million upon if certain sales milestones are achieved.

Epygenix Therapeutics CEO Alex Yang said in a statement that he believes Harmony's skills in drug development and commercialization will accelerate the full potential of EPX-100 and "make a real difference in the lives" of Dravet and Lennox-Gastaut syndrome families.

Harmony's pipeline also includes ZYN002, a cannabidiol gel in late-stage testing as a potential treatment for fragile X syndrome, an inherited intellectual disability disorder. ZYN002 was originally developed by Devon-based Zynerba, which merged into Harmony in 2023.

Harmony has 246 employees. The company last year posted a profit of $128.9 million.