MOS118 Nasal Spray Shows Safety in Phase 1 Sleep Apnea Study

Mosanna Therapeutics has shared positive Phase 1 safety results for its MOS118 nasal spray, supporting its advancement into studies for obstructive sleep apnea. The investigational nighttime spray was well tolerated across all dose cohorts with no serious adverse events reported following both single and multiple doses in healthy volunteers. These findings clear the path for the next stage of testing in OSA patients.

The Phase 1 MOSAIC study was a randomized, double-blind, placebo-controlled evaluation with an integrated single-ascending-dose and multiple-ascending-dose design. It enrolled 32 healthy adult volunteers across four sequential dose cohorts. Safety monitoring was comprehensive, including continuous 12-lead electrocardiogram telemetry with matched pharmacokinetic assessments, nasal examinations, and local-tolerance assessments. The study evaluated the safety, tolerability, and pharmacokinetics of MOS118.

Mechanism Targets Airway Neuromuscular Control

MOS118 is an investigational, locally acting, nighttime nasal spray designed to treat obstructive sleep apnea by restoring natural neuromuscular control of the upper airway during sleep. It is a small-molecule pan-potassium channel inhibitor formulated as a microparticle suspension for intranasal administration at bedtime, intended to be retained at nasal and upper-pharyngeal target tissues to limit systemic exposure.

The spray aims to address impaired neuromuscular control. Pressure-sensing nerves in the nasal and upper airway detect negative pressure during inhalation and signal upper-airway dilator muscles to activate. This natural protective response, known as the negative pressure reflex, becomes less responsive during sleep in people with OSA. MOS118 is designed to sensitize sensory nerve endings, amplifying this reflex and restoring dilator muscle activity. David A. Weber, PhD said: "MOS118 is designed to restore the body’s natural reflex for maintaining an open airway during sleep with a simple, locally acting nasal spray."

Next Steps: Seven-Day Study in OSA Patients

Following the positive results, Mosanna will next evaluate the safety and tolerability of nightly dosing of MOS118 over seven days in 24 patients with OSA. The Phase 1 MOSAIC study is being conducted in the United States under an FDA-cleared Investigational New Drug application for MOS118.

High Unmet Need in OSA Treatment Landscape

Obstructive sleep apnea is a chronic disorder where the upper airway repeatedly narrows or collapses during sleep, interrupting breathing, reducing oxygen levels, and fragmenting sleep. These repeated disruptions are associated with broader health risks, including hypertension and cardiovascular disease. An estimated 80 million adults in the United States have OSA, but fewer than 25 million are diagnosed.

Treatment has long relied on continuous positive airway pressure machines, dental appliances, or surgery. Many diagnosed patients decline CPAP or are unable to use it consistently. While recent advances in pharmacotherapy are expanding the options, a need remains for convenient therapies that act directly on the physiology responsible for airway collapse. Mosanna Therapeutics will next evaluate the safety and tolerability of nightly dosing of MOS118 over seven days in 24 patients with OSA.