A drug approved to treat obesity in adults and teens is safe and effective for use in kids as young as 6 when combined with diet and exercise, a small new study shows.

Liraglutide lowered body mass, slowed weight gain and improved health markers in kids ages 6 through 11, according to research presented Tuesday at a medical conference and published in the New England Journal of Medicine.

Based on the results of the trial, drugmaker Novo Nordisk has asked U.S. regulators to expand use of the medication for kids in that age group, a company spokesperson said Tuesday. If approved, the drug would be the first authorized to treat the most common type of obesity that affects more than 20% of U.S. kids ages 6 through 11, according to the U.S. Centers for Disease Control and Prevention.

“To date, children have had virtually no options for treating obesity,” said Dr. Claudia Fox, a pediatric obesity expert at the University of Minnesota who led the study. “They have been told to ‘try harder’ with diet and exercise."

Side effects were common among those given the drug, particularly gastrointestinal effects such as nausea, vomiting and diarrhea. And experts said doctors and parents would need to carefully consider those risks and the lack of data about the long-term use of such drugs in young kids.

“Having a medication for that age group, if approved, would be a really nice tool to have, but we're also going to have to be careful about how widely we start using it," said Dr. Melissa Crocker, a pediatric obesity specialist at Boston Children's Hospital who wasn't involved in the study. “And I would answer that differently at 6 than I would at 11.”

Liraglutide is in a class of so-called GLP-1 drugs that include blockbuster medications like Wegovy and Mounjaro. The medications mimic hormones that affect appetite, feelings of fullness and digestion. It’s taken as a daily injection and is approved under the brand name Victoza to treat diabetes in adults and children ages 10 and older and as Saxenda to treat obesity in adults and children ages 12 to 17.

The new study, paid for by Novo Nordisk, included 82 children with a mean age of 10 and a baseline weight of about 155 pounds (70 kilograms). The average starting BMI was 31, above the threshold for childhood obesity. More than half the children had obesity-related health problems such as insulin resistance, asthma or early puberty. The results were presented at the annual meeting of the European Association for the Study of Diabetes in Madrid.

In the trial, 56 children received daily injections of up to 3 milligrams of liraglutide for nearly 13 months, while 26 got dummy medications. The kids were followed for six months afterward.

All the children received individual counseling to help them follow a plan that called for a healthy diet and 60 minutes a day of moderate to high-intensity exercise.

Researchers found that kids who took the drug for more than a year reduced their body mass index -- a measure of height and weight that can account for a child’s natural growth – by 5.8%. Children who received the dummy medication saw their BMI increase by 1.6%.

At the same time, children who received the drug slowed weight gain to 1.6% of their body weight during that period, compared with a 10% gain for those who got sham drugs.

The study found that 46% of kids who got the drug lowered their BMI by at least 5%, an amount that has been linked to improvements in health problems tied to obesity. In kids who received placebo, 9% met that mark. Lower measures of blood pressure and blood sugar were detected in children who received the drug, researchers noted.

Side effects, mostly mild to moderate, were reported in nearly 90% of both groups of participants. Gastrointestinal side effects including nausea and vomiting were reported in 80% of kids who received the drug, compared with 54% who received sham medications. Serious side effects were reported in seven children using liraglutide and two who took placebo. Six participants taking the drug left the trial because of the side effects, while no one taking placebo stopped treatment.

In the six-month follow-up, children in both groups who stopped treatment increased BMI and gained weight, the study found. The trial has been extended to include more treatment and follow up, with results expected in 2027.

Fox receives research funding from Novo Nordisk and drugmaker Eli Lilly paid directly to her institution. Those companies are also conducting trials with more powerful weekly injections of Novo's Wegovy and Lilly's Zepbound in kids as young as 6.

Dr. Alaina Vidmar, a pediatric obesity specialist at Children's Hospital Los Angeles who wasn't involved in the new study, said she has used liraglutide off-label to treat young kids and would welcome approval of the drug to increase flexibility and access.

The drug treats the underlying physiology of obesity, which is a complex, chronic disease that can occur at any age. Early use can prevent obesity and life-threatening health problems from extending into the teen years — and adulthood.

“We want these kids to have long, healthy lives,” Vidmar said. “The sooner that we can start, the more likely we can stop them from getting early onset diabetes, early onset heart disease, sleep apnea, all of those things. Doing nothing is not the right answer.”

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