The first late-stage trial of a GLP-1 drug in young children with obesity showed the treatment helped lower body mass index. But the findings also raise questions about whether obesity medications, some of which are currently approved for teenagers, should also be given to children at such a young age.
The 56-week trial tested Novo Nordisk’s Saxenda, the predecessor of Wegovy, coupled with lifestyle interventions in children ages 6 to 12. It found that those given daily injections of the drug, also called liraglutide, experienced a 5.8% decrease in BMI, compared with a 1.6% increase in the placebo group. Blood pressure and blood sugar levels also improved more in children receiving the drug.
The study, which enrolled 82 participants, also found that when children stopped taking Saxenda, their BMI started rising again, suggesting that children need to stay on medication to continue to experience the effects on weight as they grow, according to data presented Tuesday at the annual meeting of the European Association for the Study of Diabetes in Madrid and published in the New England Journal of Medicine.
Additionally, children on the drug experienced a higher rate of side effects, particularly gastrointestinal issues like nausea and vomiting that are commonly seen with the class of GLP-1 medications. Among those on the treatment, 12% experienced a serious adverse event, and 11% discontinued treatment due to side effects. That’s compared with 8% and none, respectively, in the placebo group.
The drugmakers behind GLP-1 medicines have been rapidly testing their treatments in a range of disease areas and populations. Novo has already asked regulators to expand Saxenda’s label to children as young as 6, contingent on the results of this trial, and the company is testing Wegovy, a stronger GLP-1, in that age group as well. Eli Lilly is also studying its obesity treatment Zepbound in children.
The argument for treating children is that staving off obesity earlier on can help prevent downstream health problems. “We now have a viable treatment option for children who have obesity, for whom lifestyle therapy is simply insufficient,” said lead author Claudia Fox, co-director of the Center for Pediatric Obesity Medicine at University of Minnesota Medical School.
But some doctors are concerned about potential dangers of giving medications to children so young, and noted there’s a lack of data on whether long-term use of drugs could affect development and puberty or cause other side effects. The authors of the new study said they saw similar changes in markers of growth such as height, bone age, and puberty status between the treatment and placebo groups. They’re continuing to collect data in an ongoing open-label extension study that is expected to end in January 2027.
There’s also concern that a drug that affects food intake could raise the risk of eating disorders in children. The researchers said they did not monitor for eating disorders in the trial and children with a diagnosis of bulimia were not allowed to enroll.
In an interview, Martin Lange, Novo’s head of development, said he so far hasn’t seen evidence of the drug affecting children’s growth and development, but “our commitment is to investigate our drugs in all populations where we get approved, so that would be part of our commitment to continue to to assess that.”
Even before this new data on young children, experts were already conflicted on how to address obesity in teenagers. Last year, the American Academy of Pediatrics issued recommendations that obesity drugs may be considered for kids 12 and older with obesity.
Meanwhile, the U.S. Preventive Services Task Force concluded that existing evidence was “inadequate” to recommend obesity drugs, including Saxenda, for children and adolescents, citing the small number of studies and limited data on long-term treatment harms. Instead, the USPSTF came down on the side of intensive behavioral interventions, not obesity medications.
The new findings are likely to stir even greater debate. On one hand, some doctors not involved with the study pointed to rising rates of obesity in children and argued that lifestyle interventions haven’t been enough to help.
“Right now we encourage lifestyle changes, so diet and activity, but that’s really hard for some people to achieve success,” said Olga Gupta, a pediatric endocrinologist at Duke University who wasn’t involved in the study. “I view medications as a tool in the toolbox.”
Gupta said it was notable that in the trial of young children, the drug appeared to have a greater effect than a previous study in teenagers — almost double the BMI difference. The researchers of the trial said this implies there may be advantages to treating obesity at an earlier age.
Melanie Cree, a pediatric endocrinologist at Children’s Hospital Colorado, said: “Obesity predicts obesity. So the thought is, if you can interrupt the cycle earlier, you treat the obesity earlier and younger so that they come into adolescence in a healthier place.”
Other doctors not involved with the study are wary of immediately turning to medications for young children.
Bob Siegel, director of the Center for Better Health and Nutrition at Cincinnati Children’s Hospital, favors starting with intensive lifestyle changes in diet and exercise, given the lifetime ahead for 6-year-olds and the limited knowledge about long-term medication use.
“You’re talking about a child 7 years of age. If you get them into the normal range or desirable range for BMI, one can expect that child on average to live another 70, 80 years to be on a GLP-1 or similar medication for that length of time,” he said in an interview. “I mean, we just don’t know what the long-term consequences of that are.”
Melissa Crocker, clinical chief of endocrinology at Boston Children’s Hospital, expressed concerns about the potential effects on mental health when using medications.
“If we tell a child that they need to take an injectable medication every day, it sets up a sense that the child must be sick and something is wrong with them,” she said. “While eating disorders are more common in adolescents, we still need to be mindful of this risk and other negative mental health outcomes in younger children who can’t usually understand why we are worried about their weight and aren’t able to assent to the use of medications.”
It’s a delicate line between preventing downstream physical effects of obesity and potentially harming the mental health of children already living with stigma for their body size, she said.
“We need to help people feel comfortable in various body shapes and sizes while still keeping an eye on metabolic health. It is particularly tricky when we can’t know for sure what medical complications any individual will face as a product of their weight,” she said.
Fox thinks of the families, too.
“I feel for parents whose children are heavy and they’ve been told over and over again that the quote unquote cure to their children’s body size is getting them to the park more.”
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