Semaglutide cut teen BMI 16.1 percent in STEP TEENS, supporting Wegovy approval for ages 12 and up

The STEP TEENS trial found that weekly semaglutide injections reduced mean BMI by 16.1 percent in adolescents with obesity over 68 weeks, while adolescents taking a placebo saw their BMI rise 0.6 percent ^[1]. Investigators presented the results in November 2022 at ObesityWeek 2022, and the data supported the FDA's expansion of the Wegovy label to patients 12 and older, which Novo Nordisk announced in the first days of January 2023 ^[1].

The trial was a double-blind, randomized, placebo-controlled study of 201 adolescents with obesity ^[1]. Participants received a 2.4 mg subcutaneous semaglutide injection once a week or a placebo, and both groups also received behavioral lifestyle therapy focused on healthy diet and exercise ^[1]. The primary endpoint was mean percentage change in BMI at week 68 ^[1].

A supportive secondary endpoint measured how many adolescents lost at least 5 percent of their BMI: 77 percent of those taking semaglutide reached that threshold, compared with 20 percent of those taking placebo ^[1].

The expanded label makes Wegovy the first injectable antiobesity prescription medication approved for pediatric patients ^[1]. It covers adolescents 12 years or older whose starting BMI is at or above the 95th percentile for their age and sex, and the label advises using the drug along with a reduced-calorie meal plan and increased physical activity ^[1].

Obesity affects about 1 in 5 US adolescents between the ages of 12 and 19, and it is influenced by genetics along with socioeconomic and environmental factors, not willpower alone ^[1]. "The prevalence of teen obesity in the U.S. continues to rise, affecting teens and their families. Now, more than ever, we need new options to support teens," said Aaron S. Kelly, PhD, co-director of the Center for Pediatric Obesity Medicine at the University of Minnesota. "This FDA approval offers an additional tool to address this serious, chronic, progressive disease" ^[1].

Kathleen Dungan, MD, an endocrinologist in the Division of Endocrinology, Diabetes and Metabolism at The Ohio State University Wexner Medical Center, said semaglutide "is one of the most effective treatments available for either condition, outside of bariatric surgery," and noted evidence that it may reduce the risk of developing diabetes and may be particularly useful for people with prediabetes ^[1]. Ibiye Owei, MD, an assistant professor at Texas Tech University Health Sciences Center, described the mechanism: the drug makes people feel full sooner and suppresses appetite, partly by slowing emptying of the stomach ^[1].

Why it matters for patients

Injectable GLP-1 medications for weight management were previously approved only for adults, so this expansion gives families of adolescents 12 and older a treatment option studied specifically in that age group, with 68 weeks of trial data behind it ^[1].

The trial tested the drug alongside lifestyle therapy, so the results reflect semaglutide plus behavioral support rather than the medication alone ^[1]. The study did not establish what happens when treatment stops, and weight change after stopping semaglutide in adolescents has not been reported. Tolerability details, including how many adolescents stopped treatment because of side effects, also have not been reported. Cost and insurance coverage for adolescents have not been disclosed.

Obesity is described in the trial coverage as a serious, chronic, progressive disease that requires long-term management to prevent problems such as high blood pressure, high cholesterol and type 2 diabetes ^[1].

What happens next

The STEP TEENS results were presented in November 2022, and the Wegovy label expansion was announced in early January 2023 ^[1]. Whether longer-term adolescent data, including what happens after treatment is stopped, will be reported has not been disclosed.