A next-generation drug causes dramatic weight loss. Here’s how much.

Retatrutide is the first of Lilly’s obesity drugs that activates three hormone receptors - GLP-1 to suppress appetite, GIP to enhance insulin secretion and glucagon to aid fat burning - earning it the nickname “triple G.” In previous trials, it has been shown to boost weight loss well beyond Lilly’s and its Danish rival’s other drugs.

NEW YORK -- Eli Lilly said on Thursday its experimental obesity drug helped patients lose more than 28 per cent of their weight over a year and a half in a key trial that allows the company to seek regulatory approval and potentially launch the next-generation drug next year.

The results were in line with Wall Street expectations and could make retatrutide the most powerful weight-loss drug in the booming obesity treatment market, where Lilly is competing with Novo Nordisk.

Analysts had previously raised concerns about the drug’s side effects after earlier trial data showed patients had experienced dysesthesia, a rare abnormal skin sensation. The latest data appeared to ease some of those worries, with fewer patients reporting dysesthesia.

Shares of Lilly rose one per cent in morning trading. Novo shares were down 0.7 per cent by 1330 GMT.

In the late-stage trial in patients with obesity but not diabetes, those receiving the highest 12 milligram of retatrutide lost an average of 28.3 per cent of their weight over 80 weeks, while more than 45 per cent of participants lost at least 30 per cent, a level of efficacy the company said rivals bariatric surgery.

“That’s really a threshold that’s historically been associated with bariatric surgery,” Kenneth Custer, Eli Lilly’s president of cardiometabolic health, said in an interview. “To have that available in a medicine is a pretty big deal.”

Custer said the company hopes to launch the drug next year.

Lilly’s currently approved injection, Zepbound, and Novo’s Wegovy have shown weight loss of roughly 15 per cent to 20 per cent in different trials, while Lilly’s oral obesity pill candidate has delivered about 11 per cent weight loss.

Improved safety

Investors have been keenly focused on safety and other side effects of weight-loss drugs in development. In the trial, incidents of dysesthesia, an abnormal skin sensation, occurred in 12.5 per cent of patients on the 12 mg dose, compared with 20.9 per cent of patients on the highest dose in the December trial result. About 11 per cent of patients on the top dose discontinued due to adverse events.

“Slightly lower weight loss is countered with improved safety profile,” BMO Capital Markets analysts said in a note. “We view retatrutide’s significantly improved discontinuation rate and rates of dysesthesia as a positive that is likely to improve uptake when eventually commercialized.”

When asked about side effects, Custer said the drug’s profile was broadly consistent with other GLP-1 medicines.

In a previous trial published in December, retatrutide helped patients with obesity and osteoarthritis of the knee lose an average of 28.7 per cent of their weight over 40 weeks and reduce knee pain. In March, Lilly said another trial showed the drug helped reduce blood sugar levels and lose an average of 15.3 per cent of their weight.

Lilly said patients who continued treatment for a full two years in the latest trial lost just over 30 per cent of their body weight on average.

“This is the figure that most impresses us, given it confers a level of efficacy previously unheard of and is substantially better than even Lilly’s own tirzepatide,” Citi analyst Geoff Meacham said, referring to the blockbuster drug Lilly sells as Mounjaro and Zepbound.

(Reporting by Chris Prentice in New York and Christy Santhosh in Bengaluru; Editing by Caroline Humer and Leroy Leo)