Children received a maximum semaglutide dose of either 1.7 mg or 2.4 mg, depending on their weight at the start of the trial. (Source: File)About four in 10 children with obesity, who received once-weekly semaglutide, were no longer classified as having obesity after 68 weeks, according to topline results from a phase 3 trial released by drugmaker Novo Nordisk.The STEP Young trial, which involved 165 children aged 6 to under 12 years, found that 40.4% of children treated with semaglutide moved below the obesity threshold, compared with none in the placebo group. The trial met its primary endpoint, showing a greater reduction in body mass index (BMI) among children receiving semaglutide.Importantly, the drug was studied alongside lifestyle modification. Both the semaglutide and placebo groups followed a reduced-calorie diet and increased physical activity throughout the 68-week trial.More than 85% of the children enrolled had class II or class III severe obesity at the start of the study. In children, obesity is assessed using age- and sex-specific BMI percentiles rather than adult BMI cut-offs because children are still growing. Obesity is defined as a BMI at or above the 95th percentile for age and sex.Ania M. Jastreboff, MD, PhD, a Yale University obesity researcher and paediatric endocrinologist and director of the Yale Obesity Research Center, said childhood obesity is concerning because of its immediate and long-term effects, including the risk of obesity-related complications emerging earlier in life.“Most of the children in the STEP Young trial were classified as having severe (class II or III) obesity at baseline,” Jastreboff said, adding that treatment with semaglutide resulted in about 40% moving below the obesity threshold within roughly a year.Jastreboff is an adult and paediatric endocrinologist whose work focuses on obesity medicine and weight management. She is the founding director of the Yale Obesity Research Center and a professor of medicine and paediatrics at Yale School of Medicine.Story continues below this adChildhood obesity can be associated with cardiovascular risk factors as well as depression, eating disorders and bullying. It also tends to persist into adulthood, when obesity-related complications can emerge earlier and more severely, according to the company’s release.“For children living with obesity and their families, health challenges can begin early and affect wellbeing throughout life,” said Martin Holst Lange, executive vice president, chief scientific officer and head of research and development at Novo Nordisk. He said the company was encouraged by the results and the potential of semaglutide, alongside lifestyle changes, to help children who require medical treatment to manage obesity.The company said the overall safety and tolerability of semaglutide in the trial were consistent with findings from previous paediatric and adult studies. No new safety concerns were identified, including concerns related to growth or pubertal development.The STEP Young trial was a randomised, double-blind, placebo-controlled, multinational study. Children received a maximum semaglutide dose of either 1.7 mg or 2.4 mg, depending on their weight at the start of the trial. The primary endpoint was the change in BMI from baseline to week 68, while a key secondary endpoint assessed improvement in BMI classification.Story continues below this adDetailed results from the study are expected to be presented at the Obesity Week 2026 in Washington DC from November 14 to 17.