An experimental obesity drug significantly reduced breathing interruptions in people with obstructive sleep apnoea, according to results from two phase three trials published in the New England Journal of Medicine.
Retatrutide, developed by Eli Lilly, was tested in 691 adults with moderate-to-severe obstructive sleep apnoea who were overweight or obese. Participants received a weekly injection of the drug at doses of 4mg, 9mg or 12mg, or a placebo, and were followed for 80 weeks. ([nejm.org](https://www.nejm.org/doi/full/10.1056/NEJMoa2611477?utm_source=openai))
The study included 243 people without type 2 diabetes and 448 who had the condition. Researchers found that retatrutide produced substantially greater reductions in the apnoea–hypopnoea index (AHI) — the average number of breathing interruptions per hour of sleep — than the placebo.
Among participants without diabetes, AHI fell by an average of 34.3 events per hour with the 9mg dose and 31.7 with the 12mg dose, compared with 9.9 among those given the placebo. In the group with type 2 diabetes, the corresponding reductions were 24.7 and 25.4 events per hour, compared with 10.3 for the placebo group. ([nejm.org](https://www.nejm.org/doi/full/10.1056/NEJMoa2611477?utm_source=openai))
Participants taking retatrutide also lost between about 12% and 20% of their body weight, depending on the dose and trial group. Around 68% experienced an improvement of more than 50% in their sleep apnoea symptoms, regardless of whether they had diabetes.
The researchers also recorded a marked fall in hypoxic burden — the severity and duration of periods when oxygen levels drop during sleep. It decreased by about 75% in participants without diabetes and 65% in those with type 2 diabetes.
Retatrutide remains an investigational treatment
Retatrutide is a triple hormone receptor agonist that acts on GIP, GLP-1 and glucagon pathways. It remains an investigational medicine and has not been approved by the US Food and Drug Administration or authorised for routine use as a treatment for sleep apnoea. ([nejm.org](https://www.nejm.org/doi/full/10.1056/NEJMoa2611477?utm_source=openai))
The most common side effects reported in the trials were gastrointestinal problems. The researchers said further studies would be needed to assess the drug’s long-term safety and whether the improvements translate into fewer heart attacks, strokes and other cardiovascular events.
Sleep apnoea is associated with high blood pressure, atrial fibrillation, heart attacks and strokes. Participants in the trials also recorded improvements in measures including systolic blood pressure, LDL cholesterol, systemic inflammation and neck circumference.
Dr Virend Somers, a cardiologist at the Mayo Clinic and a co-author of the research, said the scale of the benefit among people with type 2 diabetes was unexpected. He said the findings suggested that retatrutide could eventually provide benefits beyond reducing disrupted breathing during sleep.
However, experts stressed that the results do not mean patients should stop using continuous positive airway pressure machines or other prescribed treatments. CPAP remains the standard first-line treatment for obstructive sleep apnoea, and retatrutide is not currently available as an approved alternative.
The FDA has separately warned that unauthorised products containing retatrutide are being marketed online, including items falsely labelled as being for research use or not for human consumption. The agency says retatrutide cannot legally be used in compounded medicines and warns that products sold outside regulated channels may contain the wrong ingredients, harmful substances or no active ingredient at all. ([fda.gov](https://www.fda.gov/drugs/drug-alerts-and-statements/fdas-concerns-unapproved-glp-1-drugs-used-weight-loss?2485ce93_page=2&utm_source=openai))
