A secondary analysis of the STEP TEENS trial, presented at the European Congress on Obesity (ECO 2023) and published in Obesity, demonstrates the significant effects of semaglutide on adolescent weight loss. Led by Dr. Aaron S. Kelly from the University of Minnesota, the study reveals that 45% of the adolescents who received semaglutide managed to achieve weight loss below the clinical cutoff for obesity.
The original STEP TEENS trial, published in the New England Journal of Medicine (NEJM) in 2022, demonstrated the efficacy of semaglutide in promoting weight loss among adolescents. This secondary analysis specifically examined the impact of semaglutide treatment on improvements in body mass index (BMI) categories.
The analysis included adolescents aged 12 to under 18 years with BMI in the highest 5%. Participants were randomized to receive either once-weekly subcutaneous semaglutide 2.4 mg or placebo for 68 weeks, alongside lifestyle counseling. The researchers assessed the proportion of participants who achieved improvements in BMI categories using on-treatment data.
BMI categories were defined as normal weight (BMI ≥5th to <85th percentile), overweight (BMI ≥85th to <95th percentile), obesity class I (OCI; BMI ≥95th percentile), severe obesity class II (OCII), and severe obesity class III (OCIII). OCII and OCIII were determined based on a percentage above the 95th percentile cutoff for obesity.
Out of 201 randomized adolescents, 62 (31%), 69 (34%), and 69 (34%) were classified as OCIII, OCII, and OCI, respectively. Only one participant (0.5%) fell into the overweight category and was excluded from the analysis. At the beginning of the trial, the mean body weight was 107.5 kg, and the mean BMI was 37.0 kg/m2 (OCII).
By week 68, 74% of participants in the semaglutide group achieved improvements of one or more BMI categories compared to 19% in the placebo group. Moreover, 45% of those treated with semaglutide experienced a reduction of ≥2 BMI categories, while only 3% in the placebo group achieved the same. Overall, semaglutide treatment led to a decrease in the proportion of participants classified with OCIII from 37% to 14% after 68 weeks.
At the end of the trial, 45% of participants in the semaglutide arm reached a BMI below the clinical cutoff for obesity, indicating either normal weight or overweight, compared to 12% in the placebo arm.
Dr. Kelly emphasized the clinical effectiveness of semaglutide, stating, “These results underscore the high degree of clinical effectiveness of semaglutide in adolescents with obesity.” He added, “Semaglutide reduced weight to a level below what is defined as clinical obesity in nearly 50% of the teens in our trial, which is historically unprecedented with treatments other than bariatric surgery.”