Axsome Therapeutics has reached a settlement with the only remaining first-to-file generic applicant involved in pending product litigation related to its narcolepsy treatment Sunosi, bringing an end to the company’s remaining patent litigation concerning the drug.
According to a June 3 announcement from the company, no patent litigation relating to Sunosi remains pending following the settlement.
Under the settlement agreements reached with generic drug manufacturers, five companies will be allowed to market generic versions of Sunosi beginning on September 1, 2040, if Axsome obtains pediatric exclusivity for the product. If pediatric exclusivity is not granted, generic entry may begin on March 1, 2040.
Axsome initiated legal proceedings in 2023 against Alkem Laboratories, Aurobindo Pharma, Hetero Labs, Hikma Pharmaceuticals, Sandoz and Unichem after the companies filed applications with the U.S. Food and Drug Administration seeking approval for generic versions of Sunosi. The company subsequently pursued separate patent infringement actions against the firms. The most recent litigation involved Aurobindo Pharma and continued through the end of May 2026 following legal exchanges that began in February.
Unichem became the first company to settle with Axsome in June 2024. Under that agreement, Unichem agreed not to launch its generic Sunosi product until 2042. Later in 2024, Axsome reached an agreement to dismiss pending litigation against Sandoz after Sandoz revoked its generic drug application. Hikma Pharmaceuticals continued its legal challenge until reaching a settlement in 2025 that delayed generic entry until 2040.
Hetero Labs also received a 2040 launch date through a settlement reached in 2025, while Alkem Laboratories secured the same launch timing through a settlement completed in 2026. Aurobindo remained the last generic manufacturer with pending litigation related to Sunosi before the latest agreement was reached.
Axsome said the settlement agreement must still be submitted to the U.S. Federal Trade Commission and the Department of Justice.
Commenting on the outcome, analysts at Mizuho Securities described the legal update as a “clear win” and a best-case scenario for Axsome. The analysts also pointed to a 5% movement in the company’s shares on the day the settlement was announced.
Sunosi was approved in 2019 and is one of Axsome’s three marketed products. The company acquired the treatment from Jazz Pharma in 2022 after Jazz determined that Axsome would be well positioned to ensure broad access to the medicine. Under the transaction, Jazz received $53 million and a high single-digit royalty on U.S. net sales.
Since acquiring the drug, Axsome has sought to expand Sunosi beyond its original indication of excessive daytime sleepiness associated with narcolepsy or obstructive sleep apnea. Current late-stage development programs include two pediatric ADHD studies, a phase 3 trial in major depressive disorder, a study in binge eating disorder, and a study in shift work disorder. Last year, an ADHD trial in adults produced a 45% mean reduction from baseline in ADHD symptoms.
Sunosi generated $124.8 million in sales during 2025 and contributed to Axsome’s total annual revenue of $638.5 million. According to the information provided, those sales reflected 32% growth from 2024. In the first quarter of 2026, the product generated $33.9 million in revenue, a 34% increase compared with the same period in 2025.
While Sunosi remains one of Axsome’s marketed products, the company’s antidepressant Auvelity generated $507.1 million in sales during 2025 for major depressive disorder. The drug also received an expansion into the U.S. Alzheimer’s disease agitation market in April and is now positioned for estimated peak sales of $8 billion.
Axsome has announced the resolution of the final patent dispute involving Sunosi, a treatment used for excessive daytime sleepiness associated with certain sleep disorders.
Axsome Strengthens Sunosi Market Position
By resolving the remaining patent litigation, Axsome has eliminated a major source of uncertainty surrounding future competition for Sunosi.
