What did Novo Nordisk’s STEP Young phase 3 trial find about the effectiveness and safety of once-weekly semaglutide (Wegovy), combined with a reduced-calorie diet and increased physical activity, in 165 children aged 6 to under 12—particularly the proportion who moved below the o

Novo Nordisk’s topline STEP Young results suggest that once-weekly semaglutide plus diet and activity support produced substantially greater BMI improvement than placebo in children aged 6 to under 12 with obesity. The results are promising, but detailed numerical BMI and adverse-event data have not yet been publicly reported. 3

Trial findings

• In the 165-child, randomized, double-blind, placebo-controlled trial, both groups received a reduced-calorie diet and increased physical activity. 4
• At week 68, 40.4% of semaglutide-treated children had moved below the age- and sex-specific obesity threshold, versus 0% on placebo; this result uses the “trial product estimand,” meaning it estimates outcomes assuming adherence to assigned treatment. 3
• More than 85% of participants entered the trial with severe class II or III obesity—pediatric categories corresponding to at least 120% or 140%, respectively, of the 95th BMI percentile for age and sex. 4
• Children received weekly subcutaneous semaglutide, with a maximum dose of 1.7 mg or 2.4 mg determined by their weight at trial entry. 4
• The primary endpoint—percentage change in BMI from baseline to week 68—was met: semaglutide achieved superior BMI reduction versus placebo. Novo Nordisk has not yet released the exact average percentage BMI reduction in the topline announcement. 3

Safety and development

• Novo Nordisk said overall safety and tolerability were consistent with earlier semaglutide studies in adolescents and adults, with no new safety concerns identified. 4
• It also reported no safety concerns relating to linear growth or pubertal development during the trial. 4
• Despite increased off-label use, GLP-1 weight-loss drugs are not approved for obesity in children younger than 12; approved treatment options for this age group remain limited. 3

Context and next steps

• Novo Nordisk estimates that 177 million children aged 5–19 lived with obesity globally in 2025, projected to rise to 228 million by 2040. 4
• Detailed STEP Young results are scheduled for presentation at ObesityWeek in Washington, DC, on November 14–17, 2026. 4
• The company has not stated a specific regulatory-submission date in the available topline release. Any approval for children under 12 would require review by relevant regulators; the reported findings alone do not change Wegovy’s current authorization status for that age group. 13