Apnimed Expands Portfolio of Oral Pharmacotherapies for Sleep and Breathing Diseases Through Acquisition of Global Rights to Patents Covering Sulthiame, a Differentiated Carbonic Anhydrase Inhibitor

- Apnimed and Shionogi will develop sulthiame within the Shionogi-Apnimed Sleep Science (SASS) Joint Venture for Obstructive Sleep Apnea (OSA) and other sleep-related breathing indications
- Sulthiame has successfully completed extensive Phase 2 studies in Europe and has a mechanism of action that is differentiated from AD109, Apnimed's lead asset for OSA

CAMBRIDGE, Mass., April 25, 2025  /PRNewswire/ -- Apnimed, Inc., a pharmaceutical company building the industry-leading portfolio of first-in-class oral drugs that address the root causes of obstructive sleep apnea (OSA) and other sleep-related breathing diseases, today announced that it has acquired the intellectual property and exclusive global rights to develop and commercialize sulthiame, a differentiated carbonic anhydrase inhibitor, in the broad field of sleep apnea and sleep-related breathing diseases, from Desitin Arzneimittel GmbH. Apnimed will develop sulthiame with Shionogi & Co. Ltd. through their joint venture, Shionogi-Apnimed Sleep Science (SASS). Sulthiame is currently approved for non sleep-related diseases in several regions outside the US, and has completed successful Phase 2 trials for OSA in Europe. Sulthiame has not yet been approved for any use in the US.

"This transaction represents an exciting opportunity to develop a promising new compound for OSA that is designed with a different mechanism of action from our lead program, AD109," commented Larry Miller, MD, Chief Executive Officer of Apnimed. "Sulthiame's differentiated mechanistic design offers the potential to expand the reach of treatment and further accelerate the adoption of oral therapies for OSA."

"We look forward to adding another compelling asset to the SASS pipeline," added John Keller, Ph.D. SVP, R&D Supervisory Unit and Pharmaceutical Technology Research Division, Shionogi & Co. Ltd. "Our Joint Venture, combining the scientific and medical resources of Apnimed and Shionogi, represents the most robust global effort to bring new oral, pharmacologic treatments to patients with OSA."

"Desitin is proud to have contributed to the ongoing clinical development of sulthiame, an investigational compound with compelling Phase 2 efficacy data and a favourable safety profile," said Philipp Bloching, MD, Chief Executive Officer of Desitin. "Sulthiame is now in the best possible hands to successfully complete its development and bring benefits to patients with OSA and other sleep-related breathing indications around the world."

Under the terms of the agreement, Desitin will receive an undisclosed upfront payment, future milestone payments and royalties on future sales. As part of the transaction, SASS will also explore the use of sulthiame in additional sleep and breathing diseases including Obesity Hypoventilation Syndrome (OHS).

About Sulthiame

Sulthiame is an investigational, generally well-tolerated oral carbonic anhydrase inhibitor that is designed to restore breathing stability which is often a contributing mechanism in people with OSA. Sulthiame has successfully completed two Phase 2 trials in over 300 European OSA patients, studied for a duration of up to 3 months. It has been used clinically in non-sleep indications outside the United States and has demonstrated a favorable safety profile, to date.

About Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is a serious, chronic sleep-related breathing disease in which the upper airway repeatedly collapses during sleep, leading to intermittent oxygen deprivation. It can be caused by two overlapping mechanisms: neuromuscular dysfunction during sleep and predisposing anatomic abnormalities. It has been demonstrated that OSA can affect people of all weight classes, ages and genders —there is no single "face" of the disease.  An estimated 80 million people in the United States and 1 billion people worldwide suffer from OSA. 

An individual with OSA can experience hundreds of sleep apnea events in a single night, each one reducing the blood oxygen levels and negatively impacting cellular functions vital to normal health and function. Failure to effectively treat OSA increases the risk of serious long-term health consequences, such as high blood pressure, cardiovascular disease and type 2 diabetes, along with impacts on quality of life, including daytime fatigue and cognitive function. The majority of those diagnosed with OSA refuse, abandon, or underutilize current treatment options. Currently, no available pharmacological treatments directly address the underlying neuromuscular dysfunction that is present in all people with OSA.

About SASS

Shionogi-Apnimed Sleep Science (SASS) is a joint venture of Apnimed Inc. and Shionogi & Co., Ltd. focused on accelerating the discovery, preclinical and clinical development of novel pharmacologic solutions designed to address the complex pathology of sleep apnea and related diseases.

About Apnimed

Apnimed is a privately held clinical-stage pharmaceutical company dedicated to transforming the treatment landscape for sleep-related breathing diseases. We believe the introduction of simple, once-nightly oral drugs has the potential to dramatically expand diagnosis and the reach of treatment for people with OSA. OSA, like other common chronic diseases such as diabetes or hypertension, would benefit from having multiple drugs with differing mechanisms to more fully address the heterogeneity of disease pathophysiology. Apnimed envisions a new era where novel oral therapies simplify intervention, expand the reach of diagnosis and treatment, and help more people get the oxygen and restorative sleep needed to thrive.

Based in Cambridge, Mass., Apnimed is advancing a robust pipeline of oral pharmaceutical product candidates designed to improve oxygenation in individuals living with OSA and other sleep-related breathing disorders. Our lead candidate, AD109, could become the catalyst for a new oral treatment paradigm for OSA that has been historically limited to cumbersome devices or invasive surgeries. AD109 is currently in Phase 3 clinical trials for the treatment of mild, moderate and severe OSA. Apnimed is also developing several therapies as part of its joint venture with Shionogi & Co., Ltd., Shionogi-Apnimed Sleep Science.

AD109 is an investigational once-nightly oral pill that could become the first pharmacological treatment to improve oxygenation during sleep by directly targeting the underlying neuromuscular dysfunction that can cause the upper airway to collapse in people with obstructive sleep apnea (OSA). It is a first-in-class investigational combination of aroxybutynin, a novel antimuscarinic, and atomoxetine, a selective norepinephrine reuptake inhibitor. These compounds are designed to work synergistically to target the neuromuscular root cause of OSA. In a disease characterized by complex and invasive treatment options, AD109 may offer a simple solution to help improve oxygenation and overall health and quality of life for people living with OSA. The AD109 Phase 3 clinical trial program is fully enrolled with topline results expected Q2 and Q3 2025.

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SOURCE Apnimed, Inc.