Tirzepatide cuts A1c by 2.28 points in first phase 3 trial in children and teens

In the first phase 3 trial of tirzepatide in young people, the drug lowered A1c by an average of 2.23 percentage points after 30 weeks in children and teens with youth-onset type 2 diabetes, while A1c rose slightly in those taking placebo, researchers reported on Sept. 19, 2025 in The Lancet ^[1].

The trial, called SURPASS-PEDS, screened 146 people and randomly assigned 99 aged 10 to under 18 at 39 sites in eight countries. All had type 2 diabetes that was not adequately controlled with metformin, basal insulin, or both ^[1]. Screening and randomization ran from April 12, 2022, to Dec. 27, 2023 ^[1].

Participants were assigned in equal groups to weekly tirzepatide injections of 5 mg, 10 mg, or placebo — 32, 33, and 34 people respectively ^[1]. Participants, investigators, and the study sponsor did not know who received which treatment during the 30-week double-blind period, which was followed by a 22-week open-label extension in which everyone received tirzepatide ^[1].

Mean age was 14.7 years, 61% of participants were female, and mean A1c at the start was 8.04% ^[1].

At week 30, the two tirzepatide dose groups combined showed an average A1c drop of 2.23 points, compared with a 0.05-point rise on placebo. The estimated treatment difference was -2.28 points (95% CI -2.87 to -1.69; p<0.0001) ^[1]. The researchers wrote that the glycemic effect was sustained up to 52 weeks with tirzepatide treatment ^[1].

Body mass index fell 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].

Gastrointestinal problems were the most common side effects, all mild to moderate in severity, and they became less frequent over time, according to the report ^[1]. Two participants (6%) in the 5 mg group stopped the study drug because of an adverse event ^[1]. The authors said the safety profile matched what has been reported in adults, and no deaths occurred during the study ^[1].

Tirzepatide is a dual GIP and GLP-1 receptor agonist, a different drug class from semaglutide ^[1].

The trial was funded by Eli Lilly, and several authors are Lilly employees and shareholders. Other authors reported consulting for, or serving as trial site investigators for, Lilly and Novo Nordisk ^[1].

Why it matters for patients

Type 2 diabetes that begins in childhood or the teen years tends to behave differently from adult-onset disease, and the report notes that treatment options for young people are limited and have shown lower blood sugar efficacy than options for adults ^[1]. That is the gap this trial was designed to address.

A few limits are worth knowing. The randomized comparison covered 99 people over 30 weeks; longer-term safety and effectiveness in this age group beyond the 52 weeks of the study have not been established ^[1]. The published abstract does not report how many participants were taking insulin, or rates of low blood sugar, and those details are not yet known from the report text.

What regulators will do with the data has not been reported. The results do not by themselves change which medicines are cleared for people under 18, and there is no statement in the published report or the trial's registry record about a filing for a pediatric indication ^[1][2]. The registry entry lists the study as NCT05260021 ^[1][2].

The trial population was small and drawn from eight countries, so the findings may not reflect every patient seen in U.S. clinics. And the study tested tirzepatide only against placebo, not against other diabetes medicines used in young people, so no head-to-head comparison with existing pediatric options is available from this trial ^[1].

What happens next

The trial is listed as completed, with results covering the 30-week blinded period and the 52-week tirzepatide treatment period ^[1][2]. A correction notice about the paper appeared in The Lancet on Oct. 4, 2025, posted online Sept. 25, 2025; the PubMed listing does not describe what the notice corrects ^[1]. Whether the data will be submitted to the FDA or other regulators, and on what timeline, has not been reported ^[1].