Novo Nordisk Reports First STEP Young Phase 3 Data: Semaglutide Reduced BMI in Children Aged 6 to 11 With Obesity

Novo Nordisk said on September 7, 2026 that it had first results from STEP Young, a Phase 3 trial evaluating once-weekly subcutaneous semaglutide combined with a reduced-calorie diet and increased physical activity in children aged 6 to under 12 years old with obesity. The randomized, double-blind, placebo-controlled, multinational trial enrolled 165 children, more than 85% of whom had class II or III severe obesity at baseline. Participants were randomized to semaglutide, dosed up to a maximum of 1.7 mg or 2.4 mg weekly depending on baseline weight, or matching placebo, with both arms also receiving lifestyle counseling.

The trial met its primary endpoint of superior BMI reduction at week 68 for semaglutide compared with placebo. Based on the trial product estimand, which estimates the treatment effect if all children had adhered to treatment, 40.4% of children on semaglutide were no longer classified as having obesity at week 68, compared with none of the children on placebo. Supportive endpoints were assessed out to 104 weeks. Novo Nordisk said the trial was conducted to fulfill post-marketing regulatory requirements.

Ania M. Jastreboff, professor of medicine and pediatrics at Yale and director of the Yale Obesity Research Center, said in the company's announcement: "Childhood obesity is particularly concerning due to both immediate and enduring impacts on health, including a strong predilection to adult obesity and increased risk for the early emergence of obesity-related complications. Most of the children in the STEP Young trial were classified as having severe (class II or III) obesity at baseline, yet treatment with semaglutide resulted in a BMI percentile category below the obesity threshold in approximately 40% of the children within about a year of treatment."

Martin Holst Lange, Novo Nordisk's chief scientific officer and head of research and development, said: "For children living with obesity and their families, health challenges can begin early and affect wellbeing throughout life. As a pioneer in paediatric obesity medicine, we are encouraged by the positive STEP Young results and semaglutide's potential to help children living with obesity who need medical treatment, alongside lifestyle changes, to better manage their obesity."

Novo Nordisk described the overall safety and tolerability profile observed in STEP Young as consistent with previous pediatric and adult semaglutide and liraglutide trials, with no new safety concerns identified and no safety signals related to growth or pubertal development. The company did not disclose detailed adverse-event rates or a breakdown of specific side effects in the topline announcement, and said full results, including detailed safety data, will be presented at ObesityWeek 2026, the Obesity Society's annual meeting, scheduled for November 14 to 17 in Washington, D.C.

Semaglutide is currently FDA-approved as Wegovy for chronic weight management in adolescents aged 12 and older with obesity, following the earlier STEP TEENS trial, and as Ozempic and Rybelsus for type 2 diabetes in adults. It is not currently approved anywhere for weight management in children under 12. The STEP Young topline figures are corporate-announced results that have not yet been peer-reviewed or presented in full at a scientific meeting, and Novo Nordisk's announcement did not include a timeline for any regulatory filing covering this younger age group. The findings describe outcomes observed in this trial population and are not treatment or dosing guidance; any decision about pediatric obesity care should be made with a qualified clinician.