Experimental weight-loss drug shows big improvement for sleep apnea in two trials

An experimental weight-loss drug significantly reduced breathing interruptions in people with obstructive sleep apnea, according to the results of two clinical trials. The research was published in The New England Journal of Medicine.

The drug is retatrutide, made by Eli Lilly. It is being evaluated in phase 3 TRIUMPH trials as a potential treatment for obesity and related metabolic conditions. The drug has not been approved by the US Food and Drug Administration (FDA).

According to the National Sleep Foundation, obstructive sleep apnea affects more than 50 million Americans, and about 80% of cases are undiagnosed.

The two phase 3 randomized trials included 691 adults with moderate-to-severe sleep apnea and a body mass index of at least 27. Participants received once-weekly injections of retatrutide at doses of 4, 9 or 12 milligrams, or a placebo, and were followed for 80 weeks.

The trials included 243 participants without type 2 diabetes and 448 with the condition.

The researchers measured changes in the apnea-hypopnea index (AHI), which counts breathing interruptions per hour of sleep. Participants who received retatrutide lost between 12% and nearly 20% of their body weight and experienced significantly fewer breathing interruptions than those who received a placebo.

About 68% of participants experienced more than a 50% improvement in sleep apnea symptoms, regardless of whether they had type 2 diabetes.

Hypoxic burden — the severity and duration of low-oxygen episodes caused by breathing disruptions during sleep — fell by about 75% among participants without type 2 diabetes and 65% among those with the condition, the study said.

Study co-author Dr Virend Somers, a cardiologist and professor of medicine at Mayo Clinic in Rochester, Minnesota, said sleep apnea is often under-diagnosed and under-treated. He said this is a very exciting time in treating sleep apnea patients.

Somers said sleep apnea is associated with a higher risk of heart attacks, strokes, high blood pressure and atrial fibrillation. In the trial, participants experienced reductions in several cardiovascular risk factors, including systolic blood pressure, LDL cholesterol, systemic inflammation and neck circumference.

Somers also said retatrutide improved several diabetes-related measures. In participants without diabetes, insulin levels fell by more than 50%. Among those with type 2 diabetes, 40% progressed from diabetes to prediabetes and another 40% no longer met the criteria for diabetes, according to the researcher.

According to Somers, the condition completely resolved in about 25% of participants without diabetes and 15% of those with type 2 diabetes.

The study included participants who were using CPAP machines and those who were not. Somers said CPAP use generally declined during the study.

Dr Wendy Troxel, a RAND senior behavioral scientist in Utah who was not involved in the study, said CPAP remains the frontline treatment for sleep apnea. She said she hoped greater awareness of treatment options may encourage more people to get screened and seek treatment.

The researchers emphasized that the findings do not mean patients should stop using CPAP or other prescribed treatments. Additional research is needed to determine retatrutide's long-term safety and effectiveness for sleep apnea. The FDA has warned that unauthorized versions of retatrutide have been illegally marketed and sold online for weight loss.