Drugmaker Eli Lilly is claiming victory in the battle of weight loss drugs, now one of the most competitive and lucrative areas of the pharmaceutical industry. It says the SURMOUNT-5 clinical trial showed that its obesity drug, Zepbound (tirzepatide), was more effective than rival Novo Nordisk's Wegovy (semaglutide).
According to Lilly, the trial revealed that Zepbound achieved a 47% greater relative weight loss compared to Wegovy. On average, participants using Zepbound lost 20.2% of their body weight, while those on Wegovy lost 13.7%.
The SURMOUNT-5 trial was a phase 3b open-label study involving adults with obesity or who were overweight, and who also had at least one weight-related medical condition but did not have diabetes.
The trial's primary objective was to demonstrate Zepbound's superiority in weight loss over 72 weeks. It involved 751 participants across the U.S. and Puerto Rico, randomized to receive either Zepbound or Wegovy.
"Given the increased interest around obesity medications, we conducted this study to help health care providers and patients make informed decisions about treatment choice," said Dr. Leonard C. Glass, senior vice president of global medical affairs at Lilly Cardiometabolic Health.
Glass said Zepbound has a unique status as the only FDA-approved dual GIP and GLP-1 receptor agonist for obesity treatment. This mechanism, he said, helps regulate appetite and manage weight effectively, offering a new approach for patients struggling with obesity.
The trial also reported that 31.6% of Zepbound users achieved at least a 25% reduction in body weight, compared to 16.1% for Wegovy users.
Taking on Ozempic
Zepbound and Wegovy compete with Novo Nordisk’s diabetes drug, Ozempic, that has also been shown to be an effective weight-loss tool. While many physicians are generally supportive of weight loss drugs, they point out that they can cause serious side effects and might not be appropriate for everyone.
Dr. Michael Snyder, a bariatric surgeon at Denver Center for Bariatric Surgery, said he supports the appropriate use of these drugs. However, he points out the drugs appear to be most effective for patients who also make lifestyle changes.
The most common side effects for both Zepbound and Wegovy are reportedly gastrointestinal issues that are generally mild to moderate in severity.