Tokyo, Japan, October 16, 2025 – Aculys Pharma, Inc. (“Aculys”), a clinical stage biopharmaceutical company focused on commercializing innovative treatments for neurological conditions, today announced that Viatris Inc. (Nasdaq: VTRS) has completed its acquisition of Aculys.
Guided by a core philosophy of “Catalyst to Access” and a core mission to address the challenges of drug lag and loss in Japan, Aculys sourced, developed, and obtained approval for innovative medicines in the therapeutic area of central nervous system.
Aculys’ portfolio consists of two products: Spydia® Nasal Spray (diazepam), approved in Japan in June 2025 for the treatment of status epilepticus, and pitolisant, a selective/inverse agonist of the histamine H3 receptor. Viatris has said it is on track to file for marketing approval from the Ministry of Health, Labour and Welfare (MHLW) of Japan for pitolisant for the treatment of excessive daytime sleepiness (EDS) or cataplexy in adult patients with narcolepsy and for the treatment of EDS associated with obstructive sleep apnea syndrome (OSAS) by the end of 2025.
■Terms of the Transaction
Under the terms of the acquisition agreement, Viatris has made an upfront payment to Aculys shareholders as consideration for the acquisition, with additional consideration contingent upon the achievement of specified regulatory and commercial milestones, and royalties on net sales. Hidemasa Tanigaki, who had been serving as CEO of Aculys, will take on an advisory role supporting the transition of Spydia®- and pitolisant-related activities to Viatris.
“Our growth to date has been made possible through the unwavering support of patients, their families, healthcare professionals, partner companies, and all who have stood by us. The acquisition by Viatris represents a significant milestone in advancing our mission to deliver innovative treatments to more patients.” said Hidemasa Tanigaki, former CEO of Aculys.
BT Slingsby, former Co-Chairman of the Board and Co-Founder of Aculys, added:
“Aculys Pharma was launched with the vision of addressing a drug loss in Japan and Asia – specifically, the absence of globally approved treatments for patients in the region. As a medical doctor and co-founder, I am proud of the role Aculys has played in bringing forward these new medicines for patients and their families and would like to thank everyone who has supported us through this remarkable journey.”
■About Pitolisant
Pitolisant is an antagonist/inverse agonist that selectively binds to the histamine H3 receptor, an autoreceptor located in the presynaptic region of the histamine-containing neurons in the human brain that plays a critical role in regulating sleep and wake rhythm. The drug was approved by the European Medicines Agency (EMA) for the treatment of narcolepsy with or without cataplexy in 2016 and for the treatment of excessive daytime sleepiness (EDS) associated with OSAS in 2021. In 2019, the U.S. Food and Drug Administration (FDA) approved pitolisant under the brand name Wakix® for the treatment of EDS associated with narcolepsy and cataplexy associated with narcolepsy in 2020. As of September 2024, pitolisant had obtained regulatory approval in 38 countries including the U.S. and the EU for the treatment of narcolepsy, and in 29 countries in the EU for the treatment of OSAS.
Positive Pivotal study results in Japanese patients were recently achieved in both narcolepsy and OSAS. In the narcolepsy Phase 3 trial, the primary endpoint of improvement in EDS compared to a placebo group using the Epworth Sleepiness Scale (ESS) was met. Statistically significant difference in ESS was observed between the two groups. Furthermore, the key secondary endpoint of the frequency of cataplexy attacks showed a suppression effect comparable to that observed in prior global Phase 3 trials. No serious adverse effects were noted, and the safety and tolerability results were consistent with global clinical trials.
The OSAS Phase 3 trial evaluated the effect of pitolisant in Japanese patients with OSAS who were experiencing residual EDS despite treatment with CPAP therapy. At the end of the 12-week treatment period, patients receiving pitolisant scored lower on the ESS used to measure EDS compared to those in the placebo group and this difference was statistically significant (p=0.007). Additionally, safety and tolerability were consistent with results from global clinical studies.
■About Spydia® (diazepam)
In Japan, Aculys Pharma received marketing approval for Spydia® Nasal Spray 5 mg, 7.5 mg, and 10 mg for the treatment of status epilepticus in June 2025. This is the first intranasal anti-seizure medication approved in Japan for the treatment of status epilepticus or seizures with potential progression to status epilepticus in patients 2 years or older. It is also the first rescue medication approved for adults for out-of-hospital use.
This drug was developed by Neurelis, Inc. in the US and Aculys Pharma obtained exclusive development and commercialization rights in Japan and certain markets in the Asia-Pacific region, including Australia, Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, New Zealand, Philippines, South Korea, Thailand and Vietnam. In 2020, the FDA approved diazepam nasal spray under the brand name Valtoco® for the acute treatment of intermittent, stereotypic episodes of frequent seizure activity that are distinct from a usual seizure pattern in patients with epilepsy aged 6 years and older. In April 2025, the FDA extended the indication to include patients aged 2 years and older. Diazepam has been used for approximately 60 years in Japan, primarily in injectable form as a treatment for epileptic seizures.
■About Viatris
Viatris (Nasdaq: VTRS) is a global healthcare company uniquely positioned to bridge the traditional divide between generics and brands, combining the best of both to more holistically address healthcare needs globally. With a mission to empower people worldwide to live healthier at every stage of life, we provide access at scale, currently supplying high-quality medicines to approximately 1 billion patients around the world annually and touching all of life’s moments, from birth to the end of life, acute conditions to chronic diseases. With our exceptionally extensive and diverse portfolio of medicines, a one-of-a-kind global supply chain designed to reach more people when and where they need them, and the scientific expertise to address some of the world’s most enduring health challenges, access takes on deep meaning at Viatris. We are headquartered in the U.S., with global centers in Pittsburgh, Shanghai and Hyderabad, India. Learn more at viatris.com and investor.viatris.com, and connect with us on LinkedIn, Instagram, YouTube and X.
■About Aculys Pharma, Inc.
Aculys Pharma is a clinical stage biopharmaceutical company that is pioneering ways to eliminate drug lag/drug loss in Japan and is working to resolve social issues related to neurological and psychiatry diseases. Its corporate name was created from the philosophy of serving as a “Catalyst to Access.” Aiming to act as a bridge for innovative medical care in the field of neuropsychiatry, Aculys Pharma develops and commercializes novel pharmaceuticals introduced from the US and European countries and provides innovations for better medical care to patients, their families, healthcare professionals, and society. Aculys Pharma is based in Tokyo, Japan, and was founded by Catalys Pacific.
Information concerning pharmaceutical products (compound under development) contained herein is not intended as advertising or as medical advice, but for disclosure of management information.