SURPASS-PEDS published: first phase 3 tirzepatide results in children and teens

Results from SURPASS-PEDS, the first phase 3 trial of tirzepatide in children and adolescents, were published in The Lancet. In 99 participants aged 10 to under 18 with youth-onset type 2 diabetes, pooled tirzepatide lowered HbA1c by 2.23 percentage points at 30 weeks, while HbA1c rose by 0.05 points in the placebo group ^[1].

The estimated treatment difference was -2.28 percentage points (95% CI -2.87 to -1.69; p<0.0001) ^[1]. Tirzepatide is the dual GIP and GLP-1 receptor agonist sold as Mounjaro for type 2 diabetes and Zepbound for weight management in adults.

What the trial did

SURPASS-PEDS was a randomized, double-blind, placebo-controlled trial run at 39 sites in eight countries. It had a 30-week double-blind period followed by a 22-week open-label extension in which everyone received tirzepatide ^[1]. Participants had youth-onset type 2 diabetes that was not adequately controlled with metformin, basal insulin, or both, and were assigned 1:1:1 to tirzepatide 5 mg, tirzepatide 10 mg, or placebo by subcutaneous injection using a single-dose pen ^[1]. Randomization was stratified by age group (14 years or younger versus older than 14) and by which diabetes medications participants were already taking ^[1].

Between April 12, 2022 and December 27, 2023, 146 people were screened and 99 were randomly assigned: 32 to tirzepatide 5 mg, 33 to tirzepatide 10 mg, and 34 to placebo ^[1]. Sixty (61%) were female and 39 (39%) male. Mean age was 14.7 years, and mean baseline HbA1c was 8.04% ^[1]. The trial is registered as NCT05260021 and is listed as completed ^[1][2].

The numbers

Beyond the HbA1c result, BMI 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 ^[1]. The authors report that glycemic benefit was sustained through 52 weeks of tirzepatide treatment ^[1].

On safety, the most common adverse events with tirzepatide were gastrointestinal. All were described as mild to moderate in severity and decreased over time ^[1]. Two participants (6%) in the 5 mg group stopped the study drug because of an adverse event ^[1]. No deaths were reported during the study period, and the investigators wrote that the overall safety profile was consistent with what has been reported in adults ^[1].

The trial was funded by Eli Lilly and Company, and several authors are Lilly employees and shareholders; other authors reported consulting or site-investigator relationships with Lilly and Novo Nordisk ^[1]. A correction notice for the paper was published in The Lancet on October 4, 2025; the specific contents of that correction are not described in the sources available here ^[1].

Why it matters for patients

Youth-onset type 2 diabetes has historically been harder to treat than the adult form. The authors note that existing options for young people are limited and have shown lower glycemic efficacy than adult treatments ^[1]. A roughly 2.3-point HbA1c advantage over placebo is a large effect in that context, and it came alongside meaningful BMI reduction.

Still, this is a small trial. Ninety-nine participants across three groups is far fewer than the thousands enrolled in adult SURPASS studies, which limits how much it can say about uncommon side effects ^[1]. The double-blind comparison lasted 30 weeks, with another 22 weeks of open-label follow-up, so longer-term effects on growth, bone, or cardiovascular outcomes in this age group are not addressed by these data.

Importantly, these sources do not state whether any regulator, including the FDA, has approved tirzepatide for people under 18 with type 2 diabetes, or whether Lilly has filed for such an expansion. That remains unknown based on what is available here. Publication of a phase 3 trial is a research milestone, not a labeling change.

What happens next

The trial itself is complete, with enrollment having closed in December 2023 and results now peer-reviewed and published ^[1]. Whether these data lead to a pediatric indication, and on what timeline, is not reported in the sources. Families weighing options for a child or teen with type 2 diabetes would need to discuss the findings and their limits with the clinician managing that care.