A new study has shown that some medications used to combat obesity are effective in helping obese or overweight patients lose weight, but that they regain a substantial part of the weight lost quickly when they stop taking them. This would be the case of Zepbound (tirzepatide), a drug developed by Eli Lilly that has recently been approved by the United States Drug Administration (FDA) for the treatment of obesity, and which is under regulatory review for weight control. in Europe.
This is the conclusion of a phase 3 SURMOUNT-4 clinical trial conducted by researchers at Weill Cornell Medicine and NewYork-Presbyterian who have found that people who stopped taking the drug regained much of that weight within a year. Furthermore, the study shows that continuing to take the medication not only promotes additional weight loss, but maintains improvements in metabolic and cardiovascular health.
The results have been published in JAMA Network and have shown that this drug is a great help for people who have health problems related to excess weight, but that it is not a quick solution to lose weight. “Obesity is one of the main causes of many diseases that we spend our time treating in medicine; “Diseases such as hypertension, heart disease, diabetes, and fatty liver disease are caused or aggravated by obesity,” said study senior author Dr. Louis Aronne, Sanford I. Weill Professor of Metabolic Research and director of the Comprehensive Center. of Weight Management, which is part of the Division of Endocrinology, Diabetes and Metabolism at Weill Cornell Medicine. “The fact that we now have drugs that are proving effective is exciting and gratifying,” he adds.
Treat obesity as a chronic disease
Tirzepatide is marketed under the name Zepbound and Mounjaro, and belongs to a new class of drugs called GLP-1 receptor agonists that were developed to treat type 2 diabetes and that, in addition to controlling blood sugar, also caused loss of weight, so pharmaceutical companies created specific formulations to help patients lose weight.
The good results obtained in a phase 3 clinical trial carried out in 2022 in which treatment with this drug caused a 20% decrease in patients’ weight over 72 weeks convinced the FDA to authorize Zepbound to treat excess weight in patients with a BMI (body mass index) of 30 or more, or those with a BMI of 27 and over and health problems such as high blood pressure or cholesterol levels.
To test the long-term effects of the slimming drug, the SURMOUNT-4 trial was launched, which was carried out in 70 locations in Argentina, Brazil, Taiwan and the United States between March 2021 and May 2023. Participants took a maximum dose tolerated of tirzepatide for 36 weeks, which produced the expected weight reduction of 20.9% with improvements in blood pressure, blood sugar and lipid levels.
“People feel much better when they lose weight, but they also need to realize that this may require them to continue taking the medication long-term.”
Subsequently, 670 participants were randomly assigned to continue tirzepatide for an additional year (52 weeks) or switch to placebo. Those who continued on tirzepatide lost an additional 5.5% compared to the placebo group, which regained 14% of their weight.
The placebo group still weighed almost 10% less than at the start of the trial, but the improvements in cardiometabolic risk factors had been reversed. Compared with placebo, tirzepatide was associated with significant improvements in BMI, lipid levels, diabetes indicators, and blood pressure. “Those who took the placebo regained about half the weight they had lost,” Dr. Aronne said. “While those who continued the medication lost another 5%, their overall weight loss was around 25%.”
The findings indicate that people may need to continue taking tirzepatide to maintain weight loss. “If you stop taking the medication, you regain the weight. There is no doubt that will happen,” Dr. Aronne said. But that shouldn’t be surprising. “Obesity is a chronic disease, like diabetes or high blood pressure. Therefore, it must be treated chronically.”
“People feel a lot better when they lose this kind of weight, so they are very excited about these treatments. But they should also realize that this may require them to continue taking the medication long-term,” says Dr. Aronne. Therefore, more studies are needed to evaluate the risks and benefits associated with these medications in the long term, especially considering the potential for their use throughout life.
