Eli Lilly targets 2027 filing for retatrutide obesity drug

Eli Lilly said it plans to seek regulatory approval for retatrutide, its experimental weekly obesity injection, in the first quarter of 2027 after the drug met goals in two additional phase three studies. The timing pushes back a possible filing that the company had previously indicated could come as soon as this year, as Lilly said it needs more time to compile and confirm manufacturing and quality-control data required by regulators.

The latest results add to the competitive weight-loss drug market, where Lilly and Novo Nordisk are building portfolios around injectable and oral treatments for obesity and diabetes. Some analysts estimate the category could reach about $100 billion in annual sales by the 2030s, while TD Cowen analysts in January projected retatrutide sales of $3.8 billion in 2030.

In one trial, adults with obesity and Type 2 diabetes who received retatrutide lost as much as 20.8% of body weight on average after 80 weeks, equivalent to nearly 50 pounds, according to Lilly. The company said patients in that study also showed improvements in a key measure of blood sugar control.

A separate late-stage trial enrolled adults with severe obesity and established cardiovascular disease, with or without diabetes. Lilly said patients on retatrutide lost up to 22.6% of body weight on average after 80 weeks, or 55.8 pounds, and the company reported reductions in certain cardiovascular risk factors.

Kenneth Custer, president of Lilly Cardiometabolic Health, said in the company’s release that Lilly believes the results give it the evidence needed to pursue global approval for retatrutide as a treatment for obesity, knee osteoarthritis pain and obstructive sleep apnea.

The safety findings were similar across the two studies and earlier retatrutide trials, according to Lilly. The most frequently reported side effects were gastrointestinal, including diarrhea, nausea and constipation, which are also associated with other medicines in the GLP-1 class.

How retatrutide differs from existing drugs

Retatrutide is known as a “triple G” therapy because it targets three hormone pathways: GLP-1, GIP and glucagon. These hormones are involved in appetite, food intake, insulin response and metabolism. By acting on all three, Lilly is seeking a broader metabolic effect than drugs that mimic one or two of the pathways.

Lilly’s Zepbound uses tirzepatide, which mimics GLP-1 and GIP. Novo Nordisk’s Wegovy uses semaglutide, which targets GLP-1. Lilly has also launched Foundayo, an obesity pill, as part of its broader effort to expand beyond its existing injection franchise.

The company has now reported positive results from five late-stage studies of retatrutide. The drug remains under regulatory review only after Lilly submits formal applications, and approval decisions will rest with health authorities that assess the full clinical, manufacturing and quality package.

This story draws on original reporting from CNBC.