Semaglutide brought 40.4% of children below the obesity BMI threshold, according to top-line results from the phase 3 STEP Young clinical trial.
Once-weekly subcutaneous
At 68 weeks, 40.4% of semaglutide-treated participants had a BMI below the age- and sex-specific obesity threshold, compared with 0% receiving placebo, according to an announcement from Novo Nordisk.¹
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The findings are top-line results and have not yet been reported in a peer-reviewed publication. Novo Nordisk said detailed data will be presented at ObesityWeek 2026 in November.
STEP Young was a randomized, double-blind, placebo-controlled, multinational trial involving 165 children with obesity. Participants received semaglutide at a maximum weekly dose of 1.7 mg or 2.4 mg, determined by baseline weight, or placebo. Both groups also received a reduced-calorie diet and increased physical activity.¹
The primary end point was percentage change in BMI from baseline through week 68. Although the company stated that the trial met this end point, it did not disclose the magnitude of BMI change, between-group treatment difference, confidence interval, or statistical significance in the announcement.
Improvement in BMI classification was a confirmatory secondary end point. Obesity was defined as BMI at or above the 95th percentile for age and sex using CDC growth charts. Class II and class III obesity were defined as BMI at least 120% and 140% of the 95th percentile, respectively. More than 85% of participants had class II or III obesity at baseline.¹
Supportive end points include anthropometric measures, cardiovascular risk factors, glucose metabolism, and body composition in a dual-energy x-ray absorptiometry subgroup. Assessments are planned at weeks 68 and 104.
Childhood obesity is associated with cardiometabolic abnormalities, psychosocial morbidity, and persistence of obesity into adulthood.²,³ Current pediatric guidance recommends intensive, family-centered health
Semaglutide is a glucagon-like peptide-1 receptor agonist that mimics endogenous GLP-1 activity involved in glucose regulation, appetite, and body weight. It has been studied across type 2 diabetes, obesity, cardiovascular disease, heart failure, chronic kidney disease, and other cardiometabolic conditions. STEP Young was conducted as part of postmarketing requirements for the semaglutide clinical development program, according to Novo Nordisk.¹
The company characterized overall safety and tolerability as consistent with earlier adult and pediatric studies of semaglutide and liraglutide and reported no new safety concerns, including signals involving growth or pubertal development. However, adverse-event frequencies, discontinuation rates, gastrointestinal events, and serious adverse events were not provided.
Interpretation therefore remains limited by the top-line nature of the disclosure, the modest sample size, and the absence of detailed efficacy and safety results. Longer follow-up will be important to determine durability, effects on cardiometabolic outcomes, consequences of treatment discontinuation, and safety during growth and puberty. The findings do not by themselves establish a new regulatory indication for children aged 6 to younger than 12 years.
