Apnimed has reported positive results from the MARIPOSA Phase IIb trial of AD109 (aroxybutynin 2.5mg/atomoxetine 75mg) for the treatment of obstructive sleep apnoea (OSA), a serious sleep disorder characterised by partial or complete upper airway closure during sleep.

The dose-finding, double-blind, placebo-controlled, randomised study has enrolled 294 participants with mild to severe OSA across 25 sites in the US.

Treatment-naive participants and a substantial proportion of OSA patients who were unable to tolerate the current standard of care therapy with positive airway pressure devices were eligible for participation in the trial.

Two doses of AD109, two doses of AD504 (a second candidate in an earlier phase of development), and atomoxetine alone were given to participants and compared against a placebo over one month.

The study also included other standard clinical endpoints to measure the improvement of sleep, oxygenation and daytime function of OSA patients.

At both doses tested, AD109 achieved its primary endpoint of a statistically significant reduction of Apnea-Hypopnea Index (AHI4), the standard measure of OSA severity, against placebo (p<0.001 vs. placebo).

AD109 also improved daytime fatigue caused by OSA with statistical significance seen on scales measuring other OSA symptoms, including PROMIS-Sleep Impairment and PROMIS-Sleep Disturbance.

No serious adverse events were observed during the AD109 study with a few unexpected adverse events, including dry mouth, insomnia and nausea.

Apnimed CEO Larry Miller said: “The MARIPOSA results provided the guidance necessary to proceed with our Phase III programme.

“The 2.5mg/75mg dose of AD109 was identified as the optimal dose that we will be taking forward.

“Based on consultation with the US Food and Drug Administration, Apnimed plans to begin two Phase III registration trials in the second half of 2023.”