Zepbound Outperforms Wegovy in Weight Loss Trial

On December 4, 2024, Eli Lilly & Co. announced that its new GLP-1 weight-loss drug, Zepbound, has demonstrated superior efficacy compared to its competitor, Wegovy, in a recent clinical trial. The study, funded by Eli Lilly, was conducted to assist healthcare providers and patients in making informed treatment decisions regarding obesity medications.

The trial's results indicated that Zepbound helped patients achieve significantly greater weight loss compared to those who received Wegovy. Dr. Leonard Glass, Lilly's senior vice president of global medical affairs at Cardiometabolic Health, expressed excitement over the findings. He emphasized that Zepbound facilitated 47% more relative weight loss than Wegovy.

The study involved 751 obese and overweight adults from across the United States. Participants were randomly assigned to receive one of the two highest doses of either Zepbound or Wegovy. According to the study results, patients who received weekly injections of Zepbound lost an average of 20.2% (50.3 pounds) of their body weight after 72 weeks. In contrast, those on Wegovy saw an average weight loss of 13.7% (33.1 pounds).

Notably, this is the first randomized clinical trial directly comparing these two rival weight-loss drugs. However, the results have not yet undergone peer review. Previous research had already suggested that Zepbound outperforms Wegovy in terms of weight loss, but this earlier research was based on existing data rather than new trials.

Despite the differences in weight loss outcomes between the two drugs, experts agree that both deliver remarkable results. Dr. Susan Spratt, an endocrinologist and senior medical director for the Population Health Management Office at Duke Health, noted that although Zepbound provided greater weight loss, both drugs produced impressive results. She described the extent of weight loss achieved with both drugs as "astounding."

Dr. Christopher McGowan, a gastroenterologist who runs a weight-loss clinic in North Carolina, highlighted that the side effects of Zepbound and Wegovy are similar. However, his patients often report better tolerance with Zepbound. Common side effects for both drugs include abdominal pain, nausea, and vomiting. Novo Nordisk, the manufacturer of Wegovy, did not comment on the findings.

Zepbound contains tirzepatide, which is also the active ingredient in Lilly's diabetes drug Mounjaro. Wegovy, on the other hand, contains semaglutide, the same drug used in Novo Nordisk's diabetes drug Ozempic. Both medications mimic a hormone that helps reduce food intake and appetite. Additionally, tirzepatide mimics a second hormone called GIP, which is believed to enhance the body's ability to break down sugar and fat.

Dr. Spratt mentioned the importance of further research to compare the impact of these drugs on health outcomes beyond weight loss. For instance, Wegovy has been shown to reduce the risk of heart disease in individuals with obesity, while Zepbound has demonstrated potential as a treatment for obstructive sleep apnea.

Dr. McGowan emphasized that weight loss is not the only consideration for patients when choosing a weight-loss drug. Factors such as cost, availability, and insurance coverage play significant roles in the decision-making process. He noted that very few patients have the luxury of being selective about their treatment due to these constraints.

In summary, the recent clinical trial has highlighted the superior weight-loss efficacy of Zepbound compared to Wegovy, providing valuable information for healthcare providers and patients in managing obesity treatment. However, as with any medical treatment, various factors must be considered when making a decision, including side effects, health outcomes, and accessibility.