A new patent settlement allows Axum Therapeutics to put down its sword against potential generic drug makers targeting its narcolepsy drug Sunoshi.
The central nervous system-focused pharmaceutical company announced in a June 3 press release that it had settled with “the only remaining first-to-file generic applicant pending in product litigation related to Axum’s product Sunosi,” ending its longstanding Sunosi intellectual property litigation docket.
The settlement would allow the five companies to sell generic versions of Sunoshi starting September 1, 2040, if Axum secures a period of pediatric exclusivity for the drug. If not, the counterfeit product could be released on March 1, 2040, the company explained. As a result, “no other patent litigation related to Sunosi will remain pending.”
New York-based Axsum said in a recent SEC filing that it brought Alkem Laboratories, Aurobindo Pharma, Hetero Labs, Hikma Pharmaceuticals, Sandoz and Unichem to court in 2023 based on generic Sunosi applications filed by each defendant with the FDA. Since then, Axam has filed a number of separate patent infringement lawsuits against both companies, most recently targeting Aurobindo in a series of lawsuits in February 2026 that continued until late last month.
Unichem first reached a settlement in June 2024, agreeing not to release generic Sansoy products until 2042. Later that year, Axum “reached an agreement” to drop its pending lawsuit against Sandoz after Sandoz withdrew its generic drug application, while Hikma continued to fight until a settlement was reached in 2025, delaying the launch of the generic drug until 2040.
Hetero was also granted a 2040 launch date in a settlement last year, and Alchem also reached a settlement this year.
This leaves Aurobindo as the last potential generic drug maker to turn to Sunoshi. Axum still needs to submit a settlement agreement to the U.S. Federal Trade Commission and the Department of Justice, according to the release.
Analysts at Mizuho Securities wrote in a recent note to clients that the legal update is a “clear victory” and “best-case scenario” for Axum, noting that the company’s stock price changed 5% on the day of the announcement.
Approved in 2019, Sunsoi is a key asset as one of Axsome’s three commercially available products. The company acquired the drug in 2022 after Jazz Pharma determined Axsum was “well-positioned” to secure broad access and sold the treatment in exchange for $53 million and “high-single-digit royalties” on U.S. net sales.
Since then, Axum has been on a mission to expand beyond its original indication to treat excessive daytime sleepiness caused by narcolepsy and obstructive sleep apnea.
Sunosi’s current late-stage studies include two pediatric ADHD trials, a Phase 3 major depressive disorder study, a bulimia nervosa study, and one shift work disorder study. Last year, ADHD trials in adults showed an average reduction in ADHD symptoms of 45% from baseline, paving the way for a series of trials in children and adolescents.
Mizuho analysts assigned mixed chances of success to Axum’s expansion efforts in ADHD, depression, bulimia and shift work disorder, noting that the drug could be a blockbuster if it works for all of them. Analysts estimate that the product’s global peak sales in 2033 will be $233 million, based solely on current metrics.
Last year, Sunsoi’s sales contributed $124.8 million to Axsome’s full-year revenue of $638.5 million, reflecting 32% growth from 2024. The drug is still growing in the first quarter of 2026, generating $33.9, a 34% increase from the same period in 2025.
But it’s Axsome’s 2022 approval of Auvelity that has propelled the company to new heights in recent years. The drug will sell $507.1 million in 2025 for the major depressive disorder indication and is now positioned to reach estimated peak sales of $8 billion thanks to its expansion into the U.S. Alzheimer’s disease drug market in April.
