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A new study found people takeing the GLP-1 Zepbound had fewer symptoms of sleep apnea. River Rock Photos/Getty Images
  • People with obesity who received the weight-loss drug Zepbound had fewer obstructive sleep apnea events, or episodes of stopped breathing during sleep.
  • The research by drug maker Eli Lilly included people who used a CPAP machine to treat their obstructive sleep apnea, and those who didn’t.
  • Experts say the breathing-related benefits seen in these studies are due to weight lost by people receiving Zepbound over the course of a year.

People with obesity experienced relief from obstructive sleep apnea — or episodes of stopped breathing during sleep — while taking anti-obesity drug Zepbound (tirzepatide), drugmaker Eli Lilly announced Apr. 17.

The results come from two yearlong clinical trials of over 400 adult patients with obstructive sleep apnea, the most common type of sleep-related breathing disorder, one that affects millions of Americans and often goes undiagnosed.

In people with obstructive sleep apnea, the upper airway becomes blocked, which causes brief pauses in breathing while asleep. This can lead to daytime fatigue, headaches and other short-term symptoms, as well as an increased risk of cardiovascular disease, diabetes and mental health changes.

The results of the studies have not been published in a peer-reviewed journal, but will be presented at the American Diabetes Association’s 84th Scientific Sessions in June, the company said.

However, the results “are significant enough to warrant utilizing medications to help people lose weight, so that their sleep apnea improves,” said Christine Ren-Fielding, MD, division chief of bariatric surgery at NYU Langone and director of the NYU Langone Weight Management Program.

She was not involved in the new studies.

Tirzepatide, sold under the brand name Zepbound, was approved by the Food and Drug Administration (FDA) for chronic weight management in November 2023. The agency previously approved the drug under the brand name Mounjaro for the treatment of type 2 diabetes.

Like Novo Nordisk’s Ozempic and Wegovy, tirzepatide belongs to a class of drugs known as GLP-1 receptor agonists. Tirzepatide also targets another hormone known as GIP, making it a dual-acting drug.

Participants in the new studies had obesity and moderate-to-severe obstructive sleep apnea, which means having 15 or more episodes per hour of stopped breathing during each night.

People with central sleep apnea were excluded from the study. This form of sleep apnea occurs when the brain doesn’t properly send signals to the muscles that control breathing.

One of the new studies involved people who were unwilling or unable to use a continuous positive airway pressure (CPAP) machine, a commonly prescribed device for treating sleep apnea. Participants were randomly assigned to receive either weekly injections of tirzepatide or an non-acting placebo.

After one year, people receiving tirzepatide had an average of 27.4 fewer apnea events per hour, compared to an average reduction of 4.8 events per hour for those in the placebo group.

The other study included people who were using a CPAP machine and planned on continuing to use it throughout the study. Half of the participants received tirzepatide and the other half received a placebo.

In the tirzepatide group, people had an average of 30.4 fewer apnea events per hour, compared to an average reduction of six events per hour in the placebo group.

In both studies, participants lost around 20% of their body weight

Current treatments for sleep apnea target the symptoms of this condition — stopped breathing — but tirzepatide addresses the underlying cause, blockages in the airway that result in breathing pauses during sleep.

There is a strong correlation between gaining weight and the risk of developing obstructive sleep apnea, explained Ren-Fielding, due to fat deposits in the neck and tongue. This can lead to the tongue blocking the flow of air during sleep, especially when lying on your back.

As a result, people are woken repeatedly throughout the night. Over time, obstructive sleep apnea “can cause serious cardiac disease and serious neurologic problems, in terms of mental awareness and falling asleep easily during the day,” Ren-Fielding said.

In addition, “sleep apnea can worsen obesity,” she said, “because people who get a terrible night’s sleep may use sugary products or caffeinated products to keep themselves awake during the day, which can lead to weight gain.”

Marijane Hynes, MD, associate clinical professor of medicine at the George Washington University School of Medicine and Health Sciences in Washington, D.C., who was not involved in the new research, said the improvements in sleep apnea symptoms among people who received Zepbound were due to them losing weight.

“For many, but not all, patients, weight loss helps improve sleep apnea,” she told Healthline. For example, “a 10% weight loss decreases obstructive sleep apnea by [around] 11 events per hour.”

Other treatments that lead to significant weight loss — such as bariatric surgery and endoscopic sleeve gastroplasty — can also relieve sleep apnea symptoms.

“With surgical weight loss, within a few months of the surgery, we see that patients no longer need their CPAP device, and they’re sleeping better and feeling better,” said Mir Ali, MD, bariatric surgeon and medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center in Fountain Valley, Calif.

These benefits remain as long as they keep the weight off.

“Obstructive sleep apnea is primarily due to obesity, so if they are able to maintain the weight loss, they will keep the beneficial effects — resolving sleep apnea, and improving diabetes and high blood pressure, etc,” said Ali, who was not involved in the new research.

Another possible effect of the new studies will be changes in the labeling of Zepbound by the FDA, said Ren-Fielding, “allowing people with sleep apnea to be prescribed this medication.”

Most participants in the two studies would have already been eligible for Zepbound for chronic weight managment. But many insurers have been hesitant to cover this drug — and other GLP-1s — when used solely for weight loss.

This is partly due to the high cost of the drug. The list price for Zepbound is about $1,000 a month, although people with insurance coverage for the drug will likely pay less. Eli Lilly also offers a savings card that allows people without insurance to get the drug for $550 a month.

In its release, Eli Lilly said it plans to submit an application to the FDA and to regulatory agencies in other countries seeking approval of the drug for treating sleep apnea in people with obesity.

This approval “would add another indication to the medication to make it easier for people to get it covered by insurance,” said Ali.

In addition, “it’s good to have more evidence to be able to say to patients, ‘If you lose weight, all these things will improve,’” he said, including sleep apnea symptoms.

In two clinical trials, people with obesity who received weight-loss drug Zepbound saw a greater average reduction in sleep apnea events over the course of a year, compared to people who received a non-acting placebo.

One study included people who were being treated for obstructive sleep apnea with a continuous positive airway pressure (CPAP) machine. The other study included people who were unwilling or unable to use this commonly prescribed device for treating sleep apnea.

Experts say the apnea-related benefits were due to the weight lost by participants while on Zepbound. In both studies, people taking the drug lost about 20% of their body weight over a year.