AD109 reduced apnea-hypopnea index versus placebo in a phase 3 trial of adults with OSA unable or unwilling to use CPAP.
A once-nightly oral combination of aroxybutynin and atomoxetine reduced obstructive sleep apnea (OSA) severity in adults unable or unwilling to use continuous positive airway pressure (CPAP), according to phase 3 SynAIRgy trial results presented at the 2026 American Thoracic Society International Conference and scheduled for publication in the American Journal of Respiratory and Critical Care Medicine.1,2
“These results provide encouraging evidence that targeting neuromuscular dysfunction can translate into meaningful clinical outcomes, aligning with our evolving understanding of the disease biology,” first author Patrick John Strollo, MD, a sleep medicine physician at the University of Pittsburgh Medical Center, said in a press release.2
The investigational therapy, AD109, combines aroxybutynin and atomoxetine and is designed to improve upper airway neuromuscular tone during sleep, addressing pharyngeal airway collapse through a pharmacologic rather than device-based approach. If approved, it would enter a treatment landscape still dominated by CPAP, oral appliances, weight management, positional therapy, and selected surgical or neurostimulation approaches.3,4
Key Facts
SynAIRgy was a randomized phase 3 trial conducted over 6 months at 69 sites in the United States and Canada. Investigators enrolled 646 adults with mild to severe OSA who either could not tolerate CPAP or refused CPAP. According to the released trial summary, patients assigned to AD109 had an approximately 44% reduction in apnea-hypopnea index (AHI), compared with an 18% reduction among those receiving placebo.1,2
Additional sleep-related oxygenation measures also favored AD109. The release reported improvements in oxygen desaturation index and hypoxic burden, along with higher overall blood oxygen levels during sleep. More than 40% of treated patients improved by at least 1 OSA disease severity category, and 18% achieved what investigators described as complete disease control.2 The summary did not provide absolute baseline or follow-up AHI values, confidence intervals, or detailed subgroup estimates.
From a safety standpoint, adverse events were described as generally mild and expected for the drug components. The most commonly reported events were dry mouth, nausea, insomnia, and difficulty urinating. However, approximately 21% of patients discontinued therapy because of adverse effects, a rate that will be important for clinicians to weigh when full peer-reviewed data are available.2
OSA is a common chronic sleep-related breathing disorder associated with intermittent hypoxemia, sleep fragmentation, daytime symptoms, and cardiometabolic comorbidity. Global prevalence estimates vary by definition and population, but epidemiologic work has suggested a substantial number of adults have clinically relevant OSA, including many who remain undiagnosed or untreated.3 For symptomatic adults, CPAP remains a central evidence-based treatment, with guideline recommendations supporting positive airway pressure for excessive sleepiness, impaired sleep-related quality of life, and comorbid hypertension in appropriate patients.4
Clinical adoption of CPAP is often limited by adherence, comfort, mask fit, nasal symptoms, and patient preference. Non-CPAP approaches may be appropriate for selected patients, but efficacy varies by anatomy, disease severity, body weight, and phenotype.4 In that context, an oral drug that improves physiologic measures of OSA could address an important gap, particularly for patients declining or not tolerating device-based therapy. Still, the available summary does not establish comparative effectiveness against optimized CPAP, mandibular advancement devices, weight-loss interventions, or hypoglossal nerve stimulation.
AD109 has received US Food and Drug Administration Fast Track designation for OSA, according to the release. Apnimed has submitted a new drug application to the FDA, and the company expects a potential Prescription Drug User Fee Act target action date in the first quarter of 2027, contingent on FDA acceptance of the application for review.2
The main near-term questions are whether the full trial publication confirms durable benefit across clinically relevant subgroups, how discontinuation affects real-world use, and whether changes in AHI and nocturnal oxygenation translate into improvements in symptoms, function, cardiovascular outcomes, or long-term adherence. For now, AD109 remains investigational, and CPAP continues to be the reference standard for most adults requiring active OSA treatment.
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