SURPASS-PEDS published: tirzepatide cuts HbA1c 2.23 percent in youth with type 2 diabetes

Tirzepatide, the drug sold as Mounjaro for type 2 diabetes and Zepbound for obesity, sharply lowered blood sugar and body mass index in children and adolescents with type 2 diabetes in a phase 3 trial published in The Lancet ^[1][2]. The study, called SURPASS-PEDS, is one of the first large randomized tests of a dual GIP/GLP-1 receptor agonist in this age group ^[2].

What the trial tested

Researchers enrolled participants aged 10 to under 18 whose type 2 diabetes was not adequately controlled on metformin, basal insulin, or both ^[2]. The trial ran at 39 sites across eight countries and screened 146 young people between April 12, 2022, and December 27, 2023 ^[2]. Of those, 99 were randomly assigned 1:1:1 to weekly injections of tirzepatide 5 mg (32 participants), tirzepatide 10 mg (33), or placebo (34) ^[2]. Randomization was stratified by age group (14 or younger versus older than 14) and by which diabetes medications participants were already taking ^[2].

The group was 61% female (60 participants) and 39% male (39), with a mean age of 14.7 years and a mean starting HbA1c of 8.04% ^[2]. The main double-blind phase lasted 30 weeks, followed by a 22-week open-label extension in which everyone received tirzepatide ^[2].

The results

At week 30, HbA1c fell by an average of 2.23% in the pooled tirzepatide groups, while it rose by 0.05% on placebo ^[2]. That works out to an estimated treatment difference of -2.28% (95% confidence interval -2.87 to -1.69; p<0.0001) ^[2]. The investigators reported that the blood sugar improvement held up through 52 weeks of tirzepatide treatment ^[2].

Body mass index dropped 7.4% in the 5 mg group and 11.2% in the 10 mg group at 30 weeks, compared with 0.4% in the placebo group ^[2].

On safety, the most common side effects with tirzepatide were gastrointestinal, all rated mild to moderate, and they became less frequent over time ^[2]. Two participants (6%) in the 5 mg group stopped the study drug because of an adverse event ^[2]. The authors wrote that the overall safety profile matched what has been reported in adults, and no deaths occurred during the study ^[2].

The trial was funded by Eli Lilly and Company, the maker of tirzepatide, and several authors are Lilly employees and shareholders ^[2]. Other authors reported consulting fees, grant support, or site-investigator roles with Lilly, Novo Nordisk, and other companies ^[2]. The study is registered as NCT05260021 ^[2]. The Lancet published a correction notice, "Department of Error," on October 4, 2025; the specific content of that correction is not described in these sources ^[2].

Why it matters for patients

Youth-onset type 2 diabetes has historically been harder to treat than the adult form. The authors noted that existing treatment options for young people are limited and have shown lower blood-sugar-lowering efficacy than treatments studied in adults ^[2]. A drop of more than two percentage points in HbA1c from a baseline of about 8% is a large change in this context, and it came alongside meaningful BMI reduction ^[2].

For families of teens with type 2 diabetes, this trial adds randomized evidence about how tirzepatide performs in that age group specifically, rather than extrapolating from adult data. Still, the trial was small — 99 participants — and lasted 52 weeks including the open-label phase, so longer-term effects on growth, puberty, bone health, or diabetes complications were not addressed in what these sources report ^[2].

These sources also do not say whether US regulators have approved or expanded tirzepatide labeling for pediatric type 2 diabetes, or how the drug compares head-to-head with semaglutide in this age group. Those questions are not answered here.

What happens next

The trial is listed as completed ^[2]. The sources do not describe any planned follow-up study, regulatory filing, or label change tied to these results, so any next steps are not yet known from this material. Decisions about treatment for a child or teen with type 2 diabetes are made with a clinician who knows the patient's full history.