Viatris Inc., a global healthcare leader, has announced the acquisition of Aculys Pharma, Inc., a clinical-stage biopharmaceutical company based in Tokyo that focuses on developing and commercializing innovative therapies for neurological disorders. The acquisition grants Viatris the rights to develop and commercialize pitolisant and Spydia®, two advanced assets in the Central Nervous System (CNS) therapy area—further expanding the company’s innovative portfolio in Japan.
As part of the agreement, Viatris obtained exclusive development and commercialization rights in Japan for pitolisant, a selective/inverse agonist of the histamine H3 receptor. Supported by positive Phase 3 clinical results in Japanese patients and a well-established global benefit-risk profile, Viatris plans to file for marketing approval with Japan’s Ministry of Health, Labour and Welfare (MHLW) by the end of 2025. The application will seek approval for pitolisant in the treatment of excessive daytime sleepiness (EDS) or cataplexy in adults with narcolepsy, as well as EDS associated with obstructive sleep apnea syndrome (OSAS).
The deal also provides Viatris with exclusive rights in Japan and select Asia-Pacific markets for Spydia® Nasal Spray, which received approval in June 2025 in Japan for the treatment of status epilepticus—a breakthrough in acute seizure management.
“The acquisition of Aculys Pharma leverages our deep commercial infrastructure in Japan and longstanding expertise in CNS, positioning us to bring these innovative treatments to more patients in need,” said Corinne Le Goff, Chief Commercial Officer, Viatris. “The addition of pitolisant and Spydia to our portfolio of innovative products is strategically aligned with our commitment to grow in areas where we can make the greatest impact and is a great example of our business development strategy designed to complement our core strengths in markets across the world.”
This acquisition adds to Viatris’ growing pipeline of innovative therapies in Japan, which already includes:
Effexor for generalized anxiety disorder (GAD), currently under regulatory review,
Selatogrel for acute myocardial infarction (MI),
Nefecon for IgA nephropathy,
Cenerimod for systemic lupus erythematosus (SLE) — all in pivotal Phase 3 trials, and
Tyrvaya for dry eye disease, with a Phase 3 study anticipated to begin in 2026.
Terms of the Transaction
Under the acquisition agreement, Viatris has made an upfront payment to Aculys Pharma shareholders as part of the consideration. Additional payments will be contingent on achieving predefined regulatory and commercial milestones, along with royalties on future net sales.
This strategic acquisition reinforces Viatris’ commitment to neuroscience innovation and strengthens its position in Japan’s and Asia-Pacific’s CNS markets, enabling broader access to novel treatments for patients with sleep and seizure disorders.