Eli Lilly’s experimental drug retatrutide delivers significant weight loss and blood sugar improvements in phase 3 trials, potentially transforming treatment for obesity and type 2 diabetes, with regulatory approval sought in 2027.
Retatrutide, an experimental obesity and diabetes drug being developed by Eli Lilly, has delivered striking weight-loss and blood-sugar results in late-stage trials, according to data presented at the European Association for the Study of Diabetes meeting and published in The Lancet. In one phase 3 study, adults with type 2 diabetes, overweight or obesity who received the highest dose lost an average of 22.5kg, or 20.8% of body weight, over 80 weeks.
The strongest response came among participants with more severe obesity, defined in the report as a body-mass index of 35 or above. In that group, the highest dose was linked to average weight loss of 27.5kg, equal to 23.4% of body weight. By the end of the trial, people taking the top dose had, on average, moved below the obesity threshold of a body-mass index of 30.
Eli Lilly says retatrutide works as a once-weekly triple hormone receptor agonist, acting on GIP, GLP-1 and glucagon receptors at the same time. The company is studying it in phase 3 trials and says it is not yet available for public use. In a separate announcement, Lilly reported similarly strong results in another pivotal trial involving adults with severe obesity and established cardiovascular disease, where the highest dose produced average weight loss of 55.8lb, or 22.6%, over 80 weeks.
The drug also showed meaningful effects on diabetes control and markers tied to heart health. According to the report, higher doses cut average HbA1c, a measure of long-term blood sugar, by about 1.5% to 1.6%, with as many as 40% of participants reaching normal glucose levels. The study also found lower triglycerides, reduced non-HDL cholesterol, a smaller waistline and a sharp fall in C-reactive protein, a marker of inflammation. Side-effects were mostly mild to moderate and eased over time, with diarrhoea, nausea, constipation, reduced appetite and vomiting among the most common. Lilly said it plans to seek US regulatory approval in the first quarter of 2027.
Disclaimer: This content is for informational purposes only and is not intended to be a substitute for professional medical judgment, advice, diagnosis, or treatment.
