Lilly's Foundayo Pill Shrinks Sleep Apnea Severity in Obesity Trial, With FDA Filing Planned

What the studies measured and how they were run

Lilly ran two independent late-stage studies that tracked the apnea hypopnea index, or AHI, which tallies hourly breathing disruptions to gauge OSA severity and whether treatment works.

One study enrolled 363 participants who could not or chose not to use positive airway pressure devices, or PAP. The other enrolled 349 who had been on PAP for at least three months at screening and kept using it during the trial.

In both, those assigned to Foundayo started at a small dose and stepped up every four weeks to different top doses, with results assessed at 52 weeks.

The headline results

In the non-PAP group, Foundayo users saw a reduction of 21.1 AHI events each hour by week 52, compared with a 4.8-event decline on placebo. That group also saw a 43.8% overall AHI decrease compared with 6.3% on placebo, and 31.5% achieved either remission or a shift down to mild OSA based on the prespecified criteria.

Among participants continuing PAP alongside Foundayo, AHI dropped by 18.3 events per hour at the 52-week mark, versus a 5.5-event decrease on placebo. Overall AHI fell by about 27.5% for Foundayo versus 3% for placebo, and 19.6% achieved remission or mild OSA.

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Foundayo also reduced the sleep apnea specific hypoxic burden - the depth and duration of overnight oxygen drops - by 55.9% without PAP and by 45.8% with PAP. Beyond breathing metrics, the pill trimmed body weight by roughly 11% across groups at 52 weeks and lowered an inflammation marker.

Safety profile and next steps

Lilly said safety and tolerability were broadly in line with earlier studies of the pill. Gastrointestinal issues such as nausea, diarrhea, constipation and vomiting were the most frequent side effects, typically mild to moderate and similar to other GLP-1 medicines.

Drug discontinuation due to side effects occurred in about 12% on Foundayo versus 3.8% on placebo in the non PAP group, and 6.8% on Foundayo versus 0.6% on placebo among those using PAP. The company intends to file these results with the FDA by year end as it pursues U.S. clearance of a once-daily pill for moderate to severe OSA in adults who have obesity or are overweight.

Why it matters for the market

OSA stems from narrowed or blocked airways during sleep, leading to oxygen dips and blood pressure spikes linked to hypertension, heart failure and stroke. It affects nearly 1 billion adults worldwide, including 80 million Americans ages 20 and up, and most have never been diagnosed. Options are limited beyond PAP devices, though Lilly's Zepbound injection became the first medication cleared in the U.S. for OSA in December 2024. Foundayo now joins GLP-1 treatments showing potential in this condition.

"Foundayo is already making a difference for people living with obesity, and with plans to submit these results to the FDA by the end of the year, we could have the opportunity to help people living with OSA," said Dr. Thomas Seck, Lilly Cardiometabolic Health's senior vice president for product development.

The bottom line: Lilly is pursuing an additional label for a pill that is already on the market, with 52-week data that cut core sleep apnea measures and added weight loss and inflammatory benefits. For your portfolio, that is a fresh potential revenue stream in a large, underdiagnosed condition, if regulators agree.

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