Novo Nordisk and Eli Lilly Release Dueling Weight-Loss Drug Data at Milan Diabetes Conference

Since Eli Lilly published its retatrutide trial results on September 29 showing patients lost up to 25% of body weight, the obesity drug fight has moved to a stage in Milan, Italy. At the 62nd Annual Meeting of the European Association for the Study of Diabetes on September 30, Novo Nordisk and Eli Lilly both released new data aimed squarely at each other's products.

Novo Nordisk announced results from its OCTANE study, an analysis of 194 patients on the Ro telehealth platform who switched from weekly injections, either Novo's Wegovy or Lilly's Zepbound, to Novo's newer once-daily Wegovy pill. According to Novo's own press release, patients who stayed on the pill for three months lost an additional 4.1% of body weight on average, or about 8.8 pounds, from a starting weight of roughly 221.6 pounds.

The company says the share of patients classified as having obesity (a BMI of 30 or higher) fell from 87.1% to 65.5% over that three-month window. Novo's chief scientific officer, Martin Holst Lange, told CNBC the company now sees "a clear preference for orals" among patients, pointing to people who travel and don't want to refrigerate weekly shots.

Novo itself flagged the limits of that claim. The company's own release states plainly that "real-world studies evaluate associations and cannot determine causality," and lists several weaknesses: data pulled from routine telehealth visits with inconsistent timing, self-reported patient outcomes subject to bias, and a design that only counted patients who stuck with treatment, which can skew results toward people already doing well. CNBC's reporting included the same caveats. This is a company-funded analysis of its own drug, presented by the company, not an independent or peer-reviewed clinical trial.

Eli Lilly did not sit quietly. According to Ynet News, Lilly told the Milan conference its injection Mounjaro beats Wegovy on weight loss, and that its new pill, orforglipron, sold as Foundayo, outperforms Novo's oral semaglutide. Novo countered by touting Ozempic's cardiovascular benefits for diabetes patients.

The head-to-head numbers are more complicated than either company's press release suggests. Ynet reported that in the SURMOUNT-5 trial of 751 adults, Mounjaro produced 20.2% average weight loss after 72 weeks versus 13.7% for standard-dose Wegovy. But Novo has since rolled out a higher dose, Wegovy HD, at three times the original strength. Lilly claims Mounjaro still wins against that higher dose too, but Ynet noted the two drugs were never tested directly against each other; Lilly combined data from two separate trials to make that comparison. When researchers narrowed the comparison to only the period patients actually stayed on treatment, the gap shrank substantially, from roughly 4.5 percentage points down to 1.8, according to Ynet's review of the data.

Cross-trial comparisons are a well-known way to make a drug look better than a true head-to-head study would show. Anyone reading a company's own "we beat the competitor" headline should ask whether the comparison came from one trial or a stitched-together one.

Meanwhile, actual regulatory approvals are moving separately from the marketing battle. The British Heart Foundation notes that in 2026, the UK approved both the Wegovy pill and Foundayo for weight management, with Wegovy's pill dosing starting at 1.5 mg and scaling up to 25 mg. Retatrutide, despite its blockbuster trial numbers, still has not received FDA approval in the United States, a point Ars Technica's coverage of the September 29 trial results made clear.

Novo also used the Milan conference to preview data on CagriSema, an experimental combination drug the company says reduces "food noise," or persistent thoughts about eating, according to reporting picked up by Romanian outlet Goldring. Novo says CagriSema is anticipated to launch in early 2027, though no regulatory approval has been announced for that drug either.

No independent, peer-reviewed head-to-head trial has directly compared Mounjaro against Wegovy HD, or Foundayo against the Wegovy pill, under identical conditions. Until one exists, patients and doctors are left comparing marketing claims built from different trials, different patient populations, and, in Novo's OCTANE case, a company-run analysis of its own product with acknowledged selection bias. The next data points to watch are whichever company runs a true randomized comparison rather than combining separate studies after the fact.