Novo Nordisk (NYSE:NVO) said on Monday that 40.4% of children with obesity who received once-weekly semaglutide in its phase 3 STEP Young trial achieved a body mass index below the obesity threshold after 68 weeks.
The study enrolled 165 children aged 6 to under 12 with obesity. Participants received either semaglutide or placebo alongside lifestyle interventions that included a reduced-calorie diet and increased physical activity.
None of the children in the placebo group achieved a BMI below the obesity threshold during the same period, according to the company.
STEP Young trial meets primary endpoint
Novo Nordisk said the trial met its primary endpoint by demonstrating a greater reduction in BMI among children receiving semaglutide compared with placebo.
At the beginning of the study, more than 85% of participants were classified as having class II or class III severe obesity, corresponding to a BMI of at least 35 or 40, respectively, in adults.
Children received a maximum semaglutide dose of either 1.7 mg or 2.4 mg depending on their baseline weight. The treatment was administered by subcutaneous injection once a week.
“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,” said Ania M. Jastreboff, Professor of Medicine and Pediatrics at Yale and Director of the Yale Obesity Research Center.
Novo Nordisk reports no new safety concerns
Novo Nordisk said the safety and tolerability profile observed in STEP Young was consistent with previous paediatric and adult studies involving semaglutide and liraglutide.
The company reported no new safety concerns and said no safety issues related to growth or pubertal development were identified.
An estimated 177 million children aged 5 to 19 were living with obesity in 2025, with projections indicating the figure could reach 228 million by 2040.
Novo Nordisk plans to present detailed results from STEP Young at The Obesity Society’s ObesityWeek 2026 annual meeting, scheduled for November 14-17 in Washington, D.C.