Findings highlight use of once-weekly injection to expand potential options for weight reduction, A1C control, knee osteoarthritis, and obstructive sleep apnea

NEW ORLEANS, June 6, 2026 /PRNewswire/ -- First-ever type 2 diabetes and obesity phase 3 study results for retatrutide, a novel glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide 1(GLP-1), and glucagon triple hormone receptor agonist, were announced today. The findings demonstrated positive outcomes in people living with obesity and type 2 diabetes, as well as improvements in major complications, including obstructive sleep apnea and knee osteoarthritis pain and were presented today as a symposium at the 2026 Scientific Sessions of the American Diabetes Association® (ADA) in New Orleans.

Approximately 90% of people with type 2 diabetes also live with overweight or obesity. For many people living with type 2 diabetes, achieving both A1C control (a key measure of average blood glucose (blood sugar) levels and meaningful weight loss remains a significant gap, underscoring the need for additional treatment options that address both conditions simultaneously. Retatrutide is designed to target three naturally occurring hormones— GIP, GLP-1, and glucagon—to help reduce appetite, improve insulin response, increase energy use, and promote fat metabolism.

Data from the TRANSCEND-T2D-1 and TRIUMPH-1 trials follow positive landmark phase 2 data for retatrutide.

TRANSCEND-T2D-1: Novel Triple Hormone Agonist Shows Average Weight Loss of 36.6 Pounds in Patients with Type 2 Diabetes

The phase 3 TRANSCEND-T2D-1 trial, also simultaneously published in The Lancet, evaluated the safety and efficacy of monotherapy with retatrutide in adults with recent-onset type 2 diabetes who had inadequate glycemic control (A1C between ≥7.0% and ≤9.5%) despite diet and exercise alone and without the use of other diabetes medications. The randomized, double-blind, placebo-controlled trial included 537 participants with recent-onset type 2 diabetes (mean 2.5 years) and a BMI of ≥23 kg/m². Over 40 weeks, participants were randomly assigned to receive a once-weekly injection of 4 mg, 9 mg, or 12 mg of retatrutide, or placebo.

Findings demonstrated that retatrutide achieved strong glucose control, significant improvements in A1C, and substantial weight reduction. Participants experienced up to a 2% reduction in A1C and a 16.8% (average loss of 36.6 lbs.) reduction in body weight. Retatrutide also showed improvements across key cardiovascular risk factors, including LDL cholesterol (often known as "bad" cholesterol), triglycerides (fats in the blood associated with heart disease), and blood pressure. Adverse events were low, similar to those of GLP-1 receptor agonists already in use, with no new reported safety concerns. The weight loss observed in the trial did not reach its maximum magnitude by the end of 40 weeks.

"It is well established that weight reduction with currently available medications is often less for people living with type 2 diabetes compared to those without diabetes. As no other trial has reported this magnitude of weight loss, this novel treatment retatrutide has the potential to meaningfully improve the lives of newly diagnosed individuals with type 2 diabetes through life-changing weight and blood glucose management," said Harpreet Singh Bajaj, MD, MPH, lead author of the study. "The magnitude of weight loss observed with retatrutide has the potential to slow disease progression and reshape how we treat and manage type 2 diabetes."

Study authors noted that additional longer-term phase 3 trials are underway investigating the efficacy and safety of retatrutide versus semaglutide, a GLP-1 receptor agonist over 80 weeks (TRANSCEND-T2D-2), as well as retatrutide versus placebo in combination with insulin in individuals with chronic kidney disease over one year (TRANSCEND-T2D-3). 

Weekly Injection at Highest Dose Demonstrates Average of 28.3% Weight Loss at 80 weeks in Patients with Obesity

The phase 3 TRIUMPH-1Obesity trial evaluated the safety and efficacy of retatrutide on weight reduction and health in adults with obesity or overweight. The randomized, placebo-controlled trial included 2,339 participants with obesity, including a subset of participants with knee osteoarthritis and/or obstructive sleep apnea. Participants were randomly assigned to receive a once-weekly injection of 4, 9, and 12 mg retatrutide, or placebo for 80 weeks.

For the primary endpoint, participants taking retatrutide 9 mg and 12 mg lost an average of 64.4 lbs (25.9%) and 70.3 lbs (28.3%), respectively. Those taking the 4 mg dose of retatrutide, with just a single dose escalation step, lost an average of 47.2 lbs (19.0%), while 65.3% of participants taking retatrutide 12 mg achieved a BMI <30, falling under the threshold for obesity at 80 weeks. Additionally, retatrutide showed significant improvements from baseline across certain cardiovascular risk factors, including triglycerides, systolic blood pressure and high-sensitivity C-reactive protein (hsCRP).

"Affecting nearly half of Americans, obesity is a chronic neurometabolic disease which is associated with over two hundred obesity-related conditions. Effectively treating obesity provides the opportunity to dramatically improve health over a lifetime. Treatment with retatrutide, the first triple hormone receptor agonist in phase 3 of development for obesity, resulted in substantial weight reduction with nearly two thirds of participants reaching targets below the obesity threshold," said Ania M. Jastreboff, MD, PhD, professor at Yale, lead author of the study. "Importantly, in addition to significant weight reduction, treatment with retatrutide resulted in improvements in health outcomes – from decreased knee pain to fewer sleep disturbances, to clear improvements in cardiometabolic measures; effectively treating obesity meaningfully impacts the overall health of people living with obesity."

Study authors noted that additional phase 3 trials investigating the impact and safety of retatrutide in people with obesity and type 2 diabetes (TRIUMPH-2), as well as obesity and cardiovascular disease (TRIUMPH-3), are underway.

Research Presentation Details
Results of First Phase 3 Study of Retatrutide, a GIP, GLP-1, and Glucagon Receptor Agonist in Patients with T2D (TRANSCEND-T2D-1)

• Harpreet Singh Bajaj, MD, MPH
• Symposium: Unlocking the Next Frontier in Treatment of Obesity and Type 2 Diabetes with Retatrutide: A Triple Agonist, Activating the GIP, GLP-1 and Glucagon Receptors (TRANSCEND-T2D-1 and TRIUMPH-1 Results)
• Saturday, June 6 from 1:55-2:15 p.m. CT
• Ernest N. Morial Convention Center, Greater Hall A (Level 1)

Results of First Phase 3 Study of Retatrutide, a GIP, GLP-1, and Glucagon Receptor Agonist in Patients with Obesity (TRIUMPH-1)

• Ania M. Jastreboff, MD, PhD
• Symposium: Unlocking the Next Frontier in Treatment of Obesity and Type 2 Diabetes with Retatrutide: A Triple Agonist, Activating the GIP, GLP-1 and Glucagon Receptors (TRANSCEND-T2D-1 and TRIUMPH-1 Results)
• Saturday, June 6 from 2:15-2:35 p.m. CT
• Ernest N. Morial Convention Center, Greater Hall A (Level 1)

About American Diabetes Association's 2026 Scientific Sessions 
The ADA's 2026 Scientific Sessions, the world's largest scientific meeting focused on diabetes research, prevention, and care, will be held in New Orleans, LA, from June 5-8. Thousands of leading physicians, scientists, and healthcare professionals from around the world are expected to convene both in person and virtually to unveil cutting-edge research, treatment recommendations, and advances toward a cure for diabetes. Attendees will receive exclusive access to thousands of original research presentations and take part in provocative and engaging exchanges with leading diabetes experts. Join the Scientific Sessions conversation on social media using #ADASciSessions.

About American Diabetes Association 
The American Diabetes Association (ADA) is the nation's leading voluntary health organization fighting to end diabetes and helping people thrive. This year, the ADA celebrates 85 years of driving discovery and research to prevent, manage, treat, and ultimately cure diabetes—and we're not stopping. There are over 155 million Americans living with diabetes or prediabetes. Through advocacy, program development, and education, we're fighting for them all. To learn more or to get involved, visit us at diabetes.org or call 1-800-DIABETES (800-342-2383). Join us in the fight on Facebook (American Diabetes Association), Spanish Facebook (Asociación Americana de la Diabetes), LinkedIn (American Diabetes Association), and Instagram (@AmDiabetesAssn). To learn more about how we are advocating for everyone affected by diabetes, visit us on X (@AmDiabetesAssn). (@AmDiabetesAssn). To learn more about how we are advocating for everyone affected by diabetes, visit us on X (@AmDiabetesAssn). 

Media contact: press@diabetes.org 

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SOURCE American Diabetes Association