US healthcare company Viatris Inc (Nasdaq:VTRS) announced on Wednesday that it has acquired Aculys Pharma Inc, a Japan-based clinical stage biopharmaceutical company focused on commercialising innovative treatments for neurological conditions.

As part of the transaction, Viatris has acquired exclusive development and commercialisation rights in Japan for pitolisant, a selective/inverse agonist of the histamine H3 receptor. Based on the strength of recent Phase 3 clinical trial results in Japanese patients and the positive benefit-risk profile established globally, Viatris is on track to file for marketing approval from Japan's Ministry of Health, Labour and Welfare (MHLW) for the treatment of excessive daytime sleepiness (EDS) or cataplexy in adult patients with narcolepsy and for the treatment of excessive daytime sleepiness associated with obstructive sleep apnoea syndrome (OSAS) by the end of 2025.

The deal also includes exclusive rights in Japan and certain other markets in the Asia-Pacific region for Spydia Nasal Spray, which was approved in Japan in June 2025 for the treatment of status epilepticus.

This acquisition further expands Viatris' portfolio of innovative products in Japan which includes Effexor for the treatment of generalised anxiety disorder (GAD) which is under regulatory review, selatogrel in Acute MI, Nefecon in IgA nephropathy, and cenerimod in systemic lupus erythematosus (SLE), all of which have pivotal Phase 3 trials currently on going and Tyrvaya in dry eye disease for which a Phase 3 trial is anticipated to start in 2026.

Under the terms of the acquisition agreement, Viatris has made an upfront payment to Aculys Pharma shareholders as consideration for the acquisition, with additional consideration contingent upon the achievement of specified regulatory and commercial milestones, and royalties on net sales.