Lilly Eyes Zepbound Label Expansion After Clearing Phase III Sleep Apnea Study

 Lilly Biotechnology Center in San Diego, CA

Pictured: Eli Lilly's biotechnology center in San Diego, California/iStock, JHVEPhoto

Eli Lilly on Wednesday released topline data from the Phase III SURMOUNT-OSA study, which showed that its top-selling weight-loss drug Zepbound (tirzepatide) substantially improved obstructive sleep apnea symptoms in patients.

The pharma will submit these data to the FDA and other global health regulatory agencies by mid-year, according to Lilly’s announcement. Tirzepatide has previously earned the FDA’s Fast Track designation for moderate-to-severe obstructive sleep apnea (OSA).

More than 20 million adults in the U.S. suffer from moderate-to-severe OSA and the vast majority of these cases are undiagnosed and thus untreated, Jeff Emmick, senior vice president of product development at Lilly, said in a statement.

If approved in this indication, tirzepatide could address this unmet medical need, Emmick added, noting that “while there are pharmaceutical treatments for the excessive sleepiness associated with OSA, tirzepatide has the potential to be the first pharmaceutical treatment for the underlying disease.”

SUMOUNT-OSA is a randomized, double-blinded and placebo-controlled study of 469 participants with OSA and obesity. The trial was divided into two main parts: the first focused on patients who were unable or unwilling to use positive airway pressure (PAP), while the second included those who were on and planned to stay on PAP during the duration of the study.

At 52 weeks, patients in the first part of the study saw a mean reduction of 27.4 events per hour in the apnea-hypopnea index (AHI), which measures OSA severity and refers to how many times the patient’s breathing is restricted or blocked per hour of sleep. In placebo counterparts, AHI dropped by 4.8 events per hour.

A similar trend was reported in the second part of the study, with tirzepatide-treated patients reaching a mean AHI reduction of 30.4 events per hour while placebo comparators only showing an average decrease of 6.0 events per hour.

In both parts of the study, tirzepatide treatment triggered greater weight loss versus placebo.

In terms of safety, tirzepatide’s adverse event profile in SURMOUNT-OSA was consistent with what had been established in prior trials. The most common side effects were gastrointestinal in nature and were mild to moderate in severity.

Wednesday’s readout adds to the ever-expanding list of diseases that GLP-1 receptor agonists appear to be effective against.

Last month, the FDA approved Novo Nordisk’s Wegovy (semaglutide) to lower the risk of cardiovascular death, heart attack and stroke in overweight and obese adult patients with cardiovascular disease. A few days earlier, Novo released data from the Phase III FLOW study showing that semaglutide can also significantly preserve kidney health in type 2 diabetes patients with chronic kidney disease.

In February 2024, Boehringer Ingelheim’s obesity hopeful survodutide demonstrated strong potential for metabolic dysfunction-associated steatohepatitis in a Phase II study.

Tristan Manalac is an independent science writer based in Metro Manila, Philippines. Reach out to him on LinkedIn or email him at or

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