A great long-term project A trial of the weight-loss drug Wegovy (semaglutide) found that people tended to lose weight during the first 65 weeks on the drug (about a year and three months), but then reached a plateau or “set point.” . But that early weight loss was usually maintained for up to four years as long as people continued taking the weekly injections.
The results, published Monday in Nature Medicine, come from a new analysis of data from the SELECT trial, which was designed to look at the drug’s effects on cardiovascular health. The multicenter, double-blind, randomized, placebo-controlled trial specifically enrolled people with existing cardiovascular disease who were also overweight or obese but did not have diabetes. In total, the trial included 17,604 people from 41 countries. Seventy-two percent of them were men, 84 percent were white, and the average age was about 62 years old.
Last year, researchers published the primary results of the trialwhich showed that semaglutide reduced participants’ risk of heart attacks, strokes, and deaths related to cardiovascular disease. by 20 percent in the span of just over three years.
In the new analysis with even longer follow-up of the same participants, the researchers focused on their weight loss trajectories and endpoints. People taking semaglutide saw their weight decline steadily over the first 65 weeks of treatment, then plateau. However, the initial weight loss was maintained during 208 weeks (four years) of follow-up. On average, people taking the drug lost 10.2 percent of their weight, while the placebo group lost only 1.5 percent. That amounts to a treatment difference of 8.7 percent.
That weight loss is less than what has been seen in other semaglutide trials. In 2021, researchers published a study in The New England Journal of Medicine showing that people who took the drug lost 14.9 percent of their weight, while those who took a placebo lost 2.4 percent.a treatment difference of 12.5 percent.
Researchers behind the SELECT trial, which was funded by Wegovy’s maker Novo Nordisk, speculate that the different trial designs may explain the difference in weight loss. The earlier trial was designed to study weight loss in people who were specifically trying to lose weight and who also tended to be younger than those in the SELECT trial. In addition to semaglutide treatment, the previous trial included other lifestyle interventions to help with weight loss. Participants in the SELECT trial, on the other hand, were not specifically seeking to lose weight and did not receive any additional lifestyle interventions to lose weight.
Still, the researchers observed clinically significant weight loss in both sexes and across all body sizes and geographic regions. Of people who received semaglutide, 52.4 percent moved into a lower body mass index category during the trial, compared with only 15.7 percent of the placebo group. And in the semaglutide group, the proportion of people with obesity fell from 71 percent to 43.3 percent, while in the placebo group the proportion fell from 71.9 percent to 67.9 percent.
The study has limitations, notably that it primarily enrolled older white men. Therefore, the findings on weight loss may not be generalizable. However, the authors conclude that the study supports the broad use of semaglutide in people with cardiovascular disease who are also overweight or obese. The next question researchers will have to address is how long people will need to continue taking the effective but currently expensive drug.
This story originally appeared on Ars Technique.