A clinical-stage biotech betting that the future of sleep apnea isn't a machine strapped to your face - it's a nasal spray you take at bedtime.
Mosanna Therapeutics is a clinical-stage biotechnology company with a deceptively simple pitch: treat obstructive sleep apnea with a spray instead of a machine. Founded in 2022 and run out of Redwood City, California, with a second office in the Swiss pharma hub of Basel, the company emerged from stealth in June 2025 with an $80 million Series A and a lead drug called MOS118.
Obstructive sleep apnea, or OSA, is one of the most common - and most undertreated - chronic conditions in the world. An estimated 80 million-plus Americans and close to a billion people globally stop breathing repeatedly through the night as the soft tissue of the upper airway collapses. The standard of care, continuous positive airway pressure (CPAP), works when it is worn. The problem is that a large share of patients abandon the mask.
Mosanna's argument is that the field has been solving the wrong problem. Rather than treating apnea as a plumbing failure to be forced open with pressurized air, the company treats it as a neuromuscular signaling problem - a reflex that quietly switches off during sleep. Its goal is to switch it back on with a once-nightly dose delivered through the nose.
The company is not yet generating revenue. Like most biotech at this stage, it runs on venture capital and is measured by clinical milestones rather than sales. What it has assembled is a syndicate of well-known life-science investors and a management team that has taken specialty drugs to FDA approval before.
"No one has sleep apnea while awake, because our bodies instinctively keep the airway open."
The insight at the center of Mosanna is a paradox worth sitting with: no one experiences sleep apnea while awake. When you are conscious, the body runs a continuous, unnoticed safety loop. As you breathe, pressure-sensing nerves in the upper airway detect negative pressure and signal the brain's respiratory center, which tells the dilator muscles of the throat to tighten and hold the airway open. Physiologists call this the negative pressure reflex.
During sleep, that reflex weakens. In people with OSA, the muscles relax too far, the airway narrows or collapses, and breathing pauses - dozens or hundreds of times a night. The evidence that the reflex matters is direct: when researchers numb those airway nerves with lidocaine, snoring and apnea get worse and muscle activity drops.
MOS118, Mosanna's lead candidate, is designed to do the opposite. It is a first-in-class small molecule pan-K+ (potassium) channel inhibitor formulated as a microparticle suspension and sprayed into the nose at bedtime. By activating the pressure-sensing nerves in the nasopharynx, it aims to keep the negative pressure reflex firing through the night - restoring upper airway muscle tone and reducing apnea and hypopnea episodes without a mask, an implant or surgery.
A single nightly dose of MOS118, delivered as a nasal microparticle suspension.
The pan-K+ channel inhibitor stimulates pressure-sensing nerves in the nasopharynx.
The negative pressure reflex fires, raising tone in the upper airway dilator muscles.
The airway stays open, reducing apnea and hypopnea episodes during sleep.
Ultimately, the tens of millions of people living with obstructive sleep apnea - many undiagnosed, many more diagnosed but unable to tolerate their treatment. Near-term, Mosanna's stakeholders are clinical trial participants, sleep physicians and the regulators who will judge MOS118. No product is on the market yet.
CPAP and oral appliances are effective on paper but suffer from real-world adherence gaps - masks are uncomfortable, noisy and hard to sleep with. Untreated OSA is an independent risk factor for hypertension, cardiovascular disease, stroke and daytime impairment. Mosanna targets the adherence gap with something patients might actually keep using: a spray.
Sleep apnea care today is dominated by hardware - pressure machines, implants and appliances - plus a first wave of drugs. Mosanna is one of the few players approaching the airway topically, through the nose. The chart below sketches the current landscape (illustrative comparison of approach, not market share).
Its competitors keep the airway open from the outside (CPAP, oral appliances), by wiring it (Inspire-style hypoglossal nerve stimulation), or with systemic oral drugs (such as Apnimed's AD109, and the weight-loss GLP-1s now studied in OSA). Mosanna is distinct in delivering a targeted small molecule topically to the airway itself to reactivate a specific reflex - aiming for the convenience of a nasal spray with the biology of a nerve-targeted drug.
A microparticle-suspension nasal spray, engineered for a single bedtime dose that works through the night.
A first-in-class small molecule pan-K+ channel inhibitor that activates nasopharyngeal pressure-sensing nerves.
In clinical development and advancing toward Phase 2, funded by the 2025 Series A. Not yet approved.
Mosanna is a venture-backed clinical-stage biopharma. It funds discovery and trials through equity, aiming to advance MOS118 toward approval and commercialization while expanding a pipeline of airway therapeutics. The Series A was co-led by a deep bench of life-science investors:
"MOS118 is the first therapy with the potential to restore the body's natural airway reflex with the simplicity of a nasal spray."
Daniela Begolo · Managing Director, EQT Life Sciences"We look forward to partnering with him and the Mosanna team to deliver on the promise of this life-changing sleep apnea treatment."
Jeni Lee · Partner, Pivotal bioVenture Partners30+ years in biotech. Former President & CEO of Otonomy, where he led the company's IPO and the FDA approval of OTIPRIO. Prior CEO roles at MacuSight and Oculex Pharmaceuticals.
Founded Mosanna Therapeutics in 2022 to pursue a pharmaceutical approach to sleep apnea built on the airway's negative pressure reflex.
Former President of the American Academy of Sleep Medicine and Harvard Medical School faculty, with 290+ published papers on sleep disorder physiology.
35+ years leading global drug development, with contributions to approvals including Rilutek, Arixtra and venlafaxine.
40+ years in pharma and 30+ in regulatory and quality assurance; former SVP at Otonomy.
25+ years in biotech, including former CEO of Vtesse and 11 years at MedImmune as EVP of Operations.
The company is established to pursue a pharmaceutical approach to obstructive sleep apnea built on the negative pressure reflex.
The lead pan-K+ channel inhibitor is developed as a microparticle-suspension nasal spray targeting nasopharyngeal nerves.
Mosanna emerges from stealth, closes an $80M Series A, and appoints David Weber as President & CEO to drive MOS118 toward Phase 2.
It is a clinical-stage biotech developing MOS118, a bedtime nasal spray designed to treat obstructive sleep apnea by restoring the body's natural airway reflex instead of using a mechanical device like CPAP.
MOS118 is a small molecule pan-K+ channel inhibitor delivered as a nasal spray. It activates pressure-sensing nerves in the nasopharynx, triggering the negative pressure reflex that increases upper airway muscle tone and reduces apnea and hypopnea episodes.
Mosanna closed an $80 million Series A in June 2025, co-led by Pivotal bioVenture Partners, EQT Life Sciences, Forbion, Broadview Ventures and Norwest, with participation from Forty51 Ventures, Supermoon Capital and HTGF.
David Weber, Ph.D., serves as President and CEO. He has more than 30 years in biotech and previously led Otonomy through its IPO and the FDA approval of OTIPRIO. The company was founded in 2022.
No. MOS118 is still in clinical development and is advancing toward Phase 2. It is not yet approved or commercially available.