Retatrutide's ADA data add sleep apnea, knee pain and diabetes benefits

Eli Lilly presented detailed Phase 3 results for retatrutide, an experimental once-weekly injection, at the American Diabetes Association's 86th Scientific Sessions in New Orleans on June 6, 2026. The data package covered weight loss, blood sugar, knee osteoarthritis pain and obstructive sleep apnea from two trials, TRIUMPH-1 and TRANSCEND-T2D-1 ^[1][2].

Retatrutide is a "triple G" molecule: it activates receptors for GLP-1, GIP and glucagon in a single drug ^[2]. That is one more target than tirzepatide (Mounjaro/Zepbound), which hits GLP-1 and GIP. Retatrutide is investigational and legally available only to people enrolled in Lilly's clinical trials ^[1].

What the weight and complication data showed

TRIUMPH-1 randomized 2,339 adults with obesity or overweight to retatrutide 4 mg, 9 mg, 12 mg or placebo for 80 weeks, and included two "basket" sub-trials for knee osteoarthritis pain and for moderate-to-severe obstructive sleep apnea ^[1].

Average weight loss was 70.3 lbs (28.3%) on 12 mg, 64.4 lbs (25.9%) on 9 mg and 47.2 lbs (19.0%) on 4 mg ^[1]. Among people on 12 mg, 65.3% ended with a BMI below 30 — no longer meeting the BMI definition of obesity — and 33.3% reached a BMI below 25 ^[1]. In a pre-specified extension, 532 participants who started with a BMI of 35 or higher and continued to 104 weeks on 12 mg lost an average of 85.0 lbs (30.3%) ^[1].

In the knee osteoarthritis group, WOMAC pain scores fell by up to 4.3 points, or 73.1%, from a baseline of 6.0 on a 0–10 scale ^[1][2]. In the sleep apnea group, the apnea-hypopnea index dropped by up to 36.1 events per hour, a 60.6% reduction from a baseline of 58.6 events per hour ^[1][2]. Lilly's already-approved tirzepatide product, Zepbound, carries an approval for obstructive sleep apnea ^[2].

TRANSCEND-T2D-1 enrolled 537 adults with type 2 diabetes not taking diabetes medications, for 40 weeks. A1C fell by up to 2.0 percentage points from a baseline of 7.9%, with up to 90% of participants getting below 7.0%, up to 85% at or below 6.5%, and up to 46% below 5.7% — the threshold for normal blood sugar ^[1]. Weight loss on 12 mg averaged 36.6 lbs (16.8%) and had not plateaued at 40 weeks ^[1]. Those results were published simultaneously in The Lancet ^[1][2].

Side effects

Stomach and gut side effects were common and dose-related. In TRIUMPH-1, nausea occurred in 28.6%, 38.4% and 42.4% of the 4 mg, 9 mg and 12 mg groups versus 14.8% on placebo; vomiting in 10.6%, 22.8% and 25.3% versus 4.8% ^[1]. Dysesthesia — abnormal skin sensations — was reported by 5.1%, 12.3% and 12.5% versus 0.9% on placebo, and urinary tract infections by 7.5%, 8.8% and 8.4% versus 5.3% ^[1]. Lilly said these were generally mild to moderate and most resolved during treatment. Discontinuation because of side effects was 4.1%, 6.9% and 11.3% versus 4.9% on placebo ^[1].

In the diabetes trial, discontinuation rates were 2.2%, 4.5% and 5.1% versus 0.0% on placebo ^[1]. Reuters reported that 2% of diabetes patients on the lowest dose had a major adverse cardiovascular event, and that such events were not necessarily caused by the drug, based on the Lancet publication ^[2].

Why it matters for patients

Retatrutide cannot be prescribed today. Nothing in these announcements changes what is available at the pharmacy, and Lilly has not disclosed a filing or approval date in these sources — that timing is not yet known ^[1].

What the data do suggest is where the category may be heading: a single drug tested against several obesity-related conditions at once, rather than treating each separately ^[1]. For people weighing options now, the comparison points are drugs already approved, including semaglutide and tirzepatide products. These trials were placebo-controlled, not head-to-head against Wegovy or Zepbound, so they do not establish that retatrutide works better than existing drugs ^[1].

What happens next

The TRIUMPH program began in 2023, spans four global registrational trials and has enrolled more than 5,800 participants, with more results expected over the next year ^[1]. The TRANSCEND-T2D program began in 2024, covers three trials and more than 2,050 participants, also with results anticipated within a year ^[1]. Additional Phase 3 studies are testing retatrutide in chronic low back pain, cardiovascular and kidney outcomes, and fatty liver disease ^[1].