Apnimed cracks sleep apnea puzzle, hits primary goal in phase 2 study

Apnimed started the year by bagging nearly $80 million in extended series C funds and the momentum has kept up, with the sleep-apnea-focused biotech nailing its goals in a phase 2 study.

Patients with obstructed sleep apnea given AD109, an oral combo of aroxybutynin and atomoxetine, had a statistically significant improvement in a measure of condition severity compared to placebo at both of the tested dose levels, according to an announcement Monday. The primary endpoint victory was coupled with improvements in daytime fatigue, investigator Paula Schweitzer, Ph.D., said in a release. 

“For those who cannot tolerate current treatments, AD109 has the potential to be a convenient, oral pill that could improve people’s quality of life both at night and during the day,” Schweitzer said. 

The phase 2 MARIPOSA trial recruited 294 participants who were randomized to receive either two doses of AD109, two doses of AD504, a next-gen candidate in earlier development, atomoxetine alone or placebo. Apnimed recruited patients who were both treatment-naive or who couldn’t tolerate CPAP machines, the current standard of care for sleep apnea. 

Patients given the 2.5-mg/75-mg dose of AD109 had a reduction in AHI4 from 20.5 events per hour to 10.8. AHI4 measures the number of apneas and hypopneas in an hour, moments when breathing stops during sleep. Apnimed says 44% of patients treated with AD109 who completed the study had at least a 50% reduction in AHI4. 

Apnimed also found that AD109-treated patients had statistically significant improvements in daytime function as measured by the PROMIS-Fatigue scale, which was recommended to the company by the FDA. While less substantive, the company also said the med “demonstrated a trend” toward statistical significance on two other scales: PROMIS-Sleep Impairment and PROMIS-Sleep Disturbance. No serious adverse events were reported in the trial. 

Now armed with both the midstage results it was hoping for and a boatload of new cash, Apnimed is racing toward a phase 3 study slated for the second half of the year. The 2.5-mg/75-mg dose will be the regimen used in the trial, following consultations with the FDA in February. 

The planned trial launch date has been slightly pushed back from the company’s previous ETA set out earlier in the year, when Apnimed expected to begin enrolling in the second quarter. The biotech closed a $79.7 million series C extension in January, bringing the total haul for the round to just over $142 million.