New study boosts Lilly in GLP-1 weight loss fight

Eli Lilly’s tirzepatide has outperformed Novo Nordisk’s semaglutide in an extensive observational study regarding weight loss outcomes. The study, which was published in JAMA Internal Medicine, suggests that tirzepatide may offer superior benefits for weight reduction compared to semaglutide. This observation sets the stage for the results of an ongoing head-to-head clinical trial comparing these two prominent GLP-1 agonists.

Tirzepatide is the active compound in Eli Lilly's diabetes medication Mounjaro and the obesity drug Zepbound. It distinguishes itself by not only functioning as a GLP-1 agonist but also by activating the body’s GIP receptors. On the other hand, Novo Nordisk’s semaglutide, which is sold under the brand names Ozempic for diabetes and Wegovy for obesity, solely mimics the GLP-1 hormone.

The study analyzed electronic health records of 41,222 overweight or obese adults over a period from May 2022 to September 2023. The findings revealed that patients treated with tirzepatide were significantly more likely to achieve substantial weight loss compared to those who received semaglutide.

To break down the numbers, 81.8% of individuals on tirzepatide lost at least 5% of their body weight within a year of starting treatment. In contrast, only 66.5% of patients on semaglutide accomplished the same level of weight loss. More impressive, 42.3% of the tirzepatide group lost 15% or more of their body weight within the same timeframe, compared to just 18.1% of those on semaglutide.

At the six-month mark, the study indicated that patients on tirzepatide experienced an average weight reduction of 10.1%, whereas semaglutide patients saw an average loss of 5.8%. This difference became even more pronounced after one year, with tirzepatide users losing an average of 15.3% of their body weight, compared to an 8.3% reduction for those on semaglutide.

These findings highlight tirzepatide's potential as a more effective treatment for weight loss, providing greater benefits than semaglutide over both short and long-term periods. This could have significant implications for the ongoing debate over the most effective GLP-1 based therapies for weight management and diabetes treatment.

As we await the results of the direct head-to-head clinical trial, this study sets a promising precedent for tirzepatide’s effectiveness in weight reduction. The anticipation now builds to see whether the head-to-head trial will corroborate these observational study results, potentially cementing tirzepatide's position as the superior weight loss drug between the two GLP-1 heavyweights.