Retatrutide sleep apnea benefit was larger without diabetes in the TRIUMPH OSA trials

Two phase 3 trials of retatrutide sleep apnea treatment, published online in the New England Journal of Medicine on 21 October, found that Eli Lilly's weekly triple agonist cut breathing interruptions during sleep well beyond placebo. The trials enrolled 691 adults with moderate to severe obstructive sleep apnea and overweight or obesity, with or without type 2 diabetes. The effect was larger in people without diabetes. Retatrutide stays in phase 3 on our board, with a US filing for weight management planned by Lilly for early 2027.

How the TRIUMPH OSA trials were designed

The two studies were nested inside Lilly's larger TRIUMPH basket trials, which test the drug for several conditions at once. TRIUMPH 1 OSA enrolled 243 people without diabetes, and TRIUMPH 2 OSA enrolled 448 people with type 2 diabetes. Everyone had a body mass index of at least 27 and moderate to severe obstructive sleep apnea, a condition in which the upper airway collapses again and again during sleep. Participants were randomised to one of three weekly doses or to placebo for 80 weeks. The main measure was the apnea hypopnea index, or AHI, which counts pauses and shallow breaths per hour of sleep. At baseline the average AHI was 58.6 and 55.9 events per hour, which is well into the severe range.

The primary comparison used only the two higher doses against placebo. The authors applied a hybrid estimand: for people whose dropout or treatment change suggested the drug had failed, results were modelled as if they had stayed on it, while other changes were counted as they happened. Because that method can flatter a drug, the paper also reports a plain intention to treat analysis, and the two sets of numbers turned out to be very close. The trials were funded by Lilly, and six of the twelve named authors are company employees. The first author is Ronald Grunstein of the Woolcock Institute of Medical Research in Sydney, with sleep researchers from the Mayo Clinic, Harvard Medical School and UC San Diego among the coauthors.

Retatrutide sleep apnea results by trial

In TRIUMPH 1 OSA, AHI fell by 22.9, 34.3 and 31.7 events per hour on the low, middle and high doses, against 9.9 on placebo. That gives placebo adjusted reductions of 13.0, 24.4 and 21.9 events per hour. In TRIUMPH 2 OSA, among people with diabetes, the falls were 19.2, 24.7 and 25.4 events per hour against 10.3 on placebo, or 8.9, 14.4 and 15.1 after subtracting placebo. All confidence intervals stayed clear of zero. The middle dose did at least as well as the high dose in the first trial, a pattern the abstract reports without comment. In the people without diabetes, the middle dose removed about 24 more breathing events an hour than placebo, from a starting point near 59.

In the people without diabetes, the middle dose removed about 24 more breathing events an hour than placebo, from a starting point near 59.

Weight loss, the key secondary end point, tracked the same split. People without diabetes lost 12.5 to 22.2 percent of body weight on retatrutide, and people with diabetes lost 12.1 to 18.5 percent, against 4.8 and 5.6 percent on placebo. Weight loss is the most likely driver of the airway benefit, and the people with diabetes lost less weight in these trials, which fits their smaller AHI gains. Gizmodo reported that in one of the trials more than half of treated people saw their apnea resolve or fall to the mild range, and that many no longer needed a positive airway pressure machine. Those details are not in the abstract we checked. The most common side effects were gastrointestinal, as in the rest of the retatrutide programme.

What the result changes for retatrutide

On its own, the retatrutide sleep apnea readout does not move the molecule; it adds a second condition to a filing that was already coming. The parent TRIUMPH 1 trial, published in the same journal on 29 September, reported weight loss of up to 25.0 percent at 80 weeks in 2,339 adults with obesity, alongside the sleep apnea and knee osteoarthritis substudies. The diabetes trial, TRIUMPH 2, appeared in The Lancet on 10 October. Our earlier retatrutide kidney trial story covered the mechanistic kidney work that sits beside these trials. Pharmacy Times reported in July that Lilly plans to file for approval in the first quarter of 2027. Sleep apnea data of this size could support a labelled indication alongside weight management.

There is a clear precedent. Gizmodo notes that Lilly's tirzepatide, a dual GIP and GLP 1 agonist, won FDA approval for obstructive sleep apnea in late 2024, which means regulators already accept AHI reduction as the basis for a label in this disease. Retatrutide adds a third target, the glucagon receptor, which Lilly is testing for extra weight and liver effects. Cross trial comparisons of AHI are risky, though, because baseline severity, follow up length and estimands differ. Gizmodo also points out that roughly a quarter of people with sleep apnea do not have overweight or obesity, and a weight loss drug is unlikely to help them. The NEJM sleep apnea paper did not test that group at all.

Limits and what to watch next

Several limits shape how far the retatrutide sleep apnea data reach. The trials covered moderate to severe disease in people with a BMI of 27 or more, so mild apnea and lean patients are outside the evidence. AHI is a count of events, not a direct measure of daytime sleepiness, blood pressure or heart risk, and the abstract does not report those outcomes. Results for each dose are given, but the abstract offers no breakdown by sex, age or baseline severity. The 80 week horizon also leaves open what happens to breathing if people stop the drug and regain weight, which these trials were not built to test. None of this weakens the main finding. It defines where the finding applies.

For the board, the checkpoints are regulatory. The first is the US filing Lilly has signalled for early 2027, and whether it includes sleep apnea from the start or adds it later. The second is the full paper's secondary results on sleepiness and oxygen levels, which will matter to sleep physicians more than the headline count. The third is safety at scale, because a triple agonist that includes glucagon has to show that heart rate and other effects stay acceptable over years. Readers can follow every incretin molecule by stage on our tracker. Our note on why stage moves differ explains why a positive readout like this leaves retatrutide in the same column.

Conclusion

The retatrutide sleep apnea trials show large, consistent cuts in breathing events over 80 weeks, with bigger gains in people without diabetes and weight loss as the likely driver. The evidence covers moderate to severe disease in people with excess weight and comes from Lilly funded trials. Retatrutide stays in phase 3, and the next checkpoint is the filing Lilly plans for early 2027. This story is research news, not medical advice.