Another perk of weight-loss drugs? Eli Lilly's Zepbound may alleviate sleep apnea, too

• GLP-1 drugs were originally developed to treat type 2 diabetes.
• Drugmakers are discovering the injections may also aid weight loss, heart issues, and sleep apnea.
• Some scientists suspect the reason might have something to do with how GLP-1s improve inflammation.

Another new indication for injectable GLP-1 drugs: better sleep.

On Wednesday, drugmaker Eli Lilly announced positive results from a large, phase-3 clinical trial, testing Zepbound (the drug name for tirzepatide) as a treatment for sleep apnea.

In this yearlong trial of 469 people, patients with moderate to severe sleep apnea experienced, on average, roughly 27-30 fewer apnea events per hour of sleep when they took weekly injections of Zepbound, according to the company. Zepbound users also lost, on average, nearly a fifth of their body weight (18%) while on the drug.

Eli Lilly, which analysts say may be on pace to become the first trillion-dollar drug company soon, is expecting to submit these results to the US Food and Drug Administration by mid-year. The company will disclose the full data at the American Diabetes Association conference in June.

If the FDA green-lights this use, tirzepatide could be approved for moderate to severe sleep apnea patients with obesity in a year or two.

Ozempic and Mounjaro: not just for diabetes and weight loss anymore

GLP-1 drugs first emerged roughly 15 years ago to treat type 2 diabetes and help control blood sugar. But in recent years, as the drugs have gotten more powerful and easier to use, doctors and patients have started to discover that they can also help promote significant weight loss by helping people feel fuller and more satisfied with less food.

Already, GLP-1 drugs have been indicated for the treatment of:

• Obesity

• Heart disease

In clinical trials, GLP-1 drugs have also shown some promise for treating other conditions, including:

• Non-alcoholic fatty liver disease

• Addiction

• Depression

• Parkinson's and Alzheimer's

• Cancer

These breakthroughs may be tied to the gut-brain connection

Some people point to the way that weight loss can help out with many of the above conditions, saying the impacts of GLP-1 drugs on such a diverse array of health issues may just be a side effect of better weight control. But researchers who study and develop these drugs suspect that there's something bigger at play.

Recent research suggests that GLP-1 injections, which mimic hormones we produce naturally in our gut, may be having a positive effect on inflammation, which is a key driver of many diseases. Dr. Daniel Drucker, one of the pioneers of GLP-1 drugs, and a professor of medicine at the University of Toronto, suspects GLP-1s are chiefly acting on the brain, which regulates our immune system in various (and often poorly understood) ways.

"We noticed that GLP-1 reduces inflammation in many different places: in the heart, in blood vessels, in the liver, in many organs," he recently told Dr. Eric Topol on his "Ground Truths" podcast.

"So that really led us to the question, well, how does it work and affect all these organs where we don't see a lot of the receptors? And that's where we landed on the brain."