Novo Nordisk unveiled results from the STEP UP clinical trial at the European Congress on Obesity in Istanbul on Tuesday, reporting that the higher 7.2 mg dose of semaglutide marketed as Wegovy produced large average weight reductions in adults living with obesity who do not have type 2 diabetes.
The randomized study compared semaglutide at 7.2 mg and 2.4 mg against placebo over a 72-week treatment period in more than 1,400 participants. Those assigned to the 7.2 mg dose lost an average of 21% of their total body weight. For the average participant in the trial, who started at 113 kg, that percentage corresponded to roughly a 23 kg loss. Participants randomized to the 2.4 mg dose lost about 17.5% of total body weight over the same period, while the placebo group lost 2.4%.
The trial team also examined response patterns early in treatment. Investigators defined early responders as individuals who achieved at least 15% body weight loss during the first 24 weeks. Under that definition, about 27% of those on the 7.2 mg dose qualified as early responders, compared with 21% of those on 2.4 mg and 3% in the placebo arm. Among early responders, the mean reduction in body weight reached 27.7% by week 72.
A focused body composition analysis conducted in a subset of 55 participants found that the majority of the weight lost with semaglutide was attributable to reductions in fat mass. That analysis indicated 84% of the total weight loss was fat. Abdominal visceral fat declined by more than 30% in participants receiving semaglutide. By contrast, muscle mass decreased by only 10% relative to baseline in this subgroup, and assessments of muscle quality signaled improvement as measured by the amount of fat within muscle tissue.
Functional muscle performance was evaluated using a 30-second sit-to-stand test. Results showed maintenance of functional muscle strength during weight loss: test performance was comparable between participants treated with semaglutide and those receiving placebo both before and after the study period.
The STEP UP findings provide detailed data on dose-dependent weight loss, early response patterns, and changes in body composition and muscle function among adults with obesity without type 2 diabetes. The analysis highlights a greater average weight reduction with the 7.2 mg dose compared with the 2.4 mg dose across the 72-week trial period.
Contextual note - The body composition results were derived from a small subset of participants, and the early responder analysis used a predefined 24-week threshold for defining early response.