NOVO NORDISK Semaglutide Trial in Children Aged 6 to 11 Hits Endpoint
In the STEP Young phase 3 trial, 40.4% of children treated with semaglutide were no longer classified as having obesity after 68 weeks, versus none on placebo.
Novo Nordisk (NVO) said its STEP Young phase 3 trial met its primary endpoint, showing superior reduction in body mass index at week 68 for children aged 6 to under 12 treated with once-weekly subcutaneous semaglutide compared with placebo. Both arms also received a reduced-calorie diet and increased physical activity throughout the trial. The company announced the topline results on 7 September 2026 from its headquarters in Bagsværd, Denmark.
The headline finding was that 40.4% of children on semaglutide were no longer classified as having obesity at week 68, against 0% in the placebo group. That figure is based on the trial product estimand, which models the treatment effect if all children adhered to treatment, and on CDC sex- and age-specific BMI growth charts, under which obesity in children is defined as a BMI at or above the 95th percentile.
The starting point was severe. More than 85% of the children had class II or class III obesity at baseline, corresponding to a BMI at or above 35 and 40 in adults. The randomised, double-blind, placebo-controlled, multinational trial enrolled 165 children, who received a maximum dose of either 1.7 mg or 2.4 mg of semaglutide depending on their weight at the start.
On safety, the company said overall safety and tolerability were consistent with earlier paediatric and adult trials of semaglutide and liraglutide, with no new safety concerns identified. It added that no safety concerns were found for growth or pubertal development, a central question in this age group.
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 of Yale, director of the Yale Obesity Research Center.
Martin Holst Lange, executive vice president, chief scientific officer and head of Research & Development, described the company as a pioneer in paediatric obesity medicine and said the results point to semaglutide's potential in children who need medical treatment alongside lifestyle changes.
The trial was run under regulatory authorities' post-marketing requirements for the semaglutide phase 3 development programme, following earlier phase 3 results with semaglutide 2.4 mg in adults and adolescents. Semaglutide is already marketed as Wegovy, Ozempic and Rybelsus.
Novo Nordisk cited an estimated 177 million children aged 5 to 19 living with obesity in 2025, projected to reach 228 million by 2040, in a group where few clinically tested and approved treatments exist. Detailed results are to be presented at ObesityWeek 2026 in Washington DC from 14 to 17 November.
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