In a 30‑week trial, tirzepatide dramatically lowered blood sugar (about 2.2% drop in HbA1c) and cut body weight (7‑11% reduction in BMI) in teens with type‑2 diabetes, with effects staying strong for a year. Side effects were mainly mild stomach issues that got better over time, and the safety looked similar to what’s seen in adults.

Current treatment options for youth-onset type 2 diabetes are limited and have demonstrated lower glycaemic efficacy than those for adult-onset type 2 diabetes. We aimed to assess the safety and efficacy of tirzepatide, a glucose-dependent insulinotropic polypeptide and GLP-1 receptor agonist, compared with placebo in youth-onset type 2 diabetes. We conducted a phase 3, double-blind, placebo-controlled, multicentre (39 sites), multinational (eight countries) trial over 30 weeks, followed by an open-label extension for 22 weeks in which all participants received tirzepatide. Participants aged 10 to <18 years with youth-onset type 2 diabetes inadequately controlled with metformin and/or basal insulin were randomly assigned (1:1:1) to receive tirzepatide 5 mg, 10 mg, or placebo administered by subcutaneous injection with a single-dose pen. Randomisation was stratified by age group (≤14 years or >14 years) and antihyperglycaemic medication use (metformin, basal insulin, or both). All participants, investigators, and the sponsor were masked to treatment assignment during the 30-week double-blind period. The primary endpoint was change in glycated haemoglobin (HbA_1c) from baseline to week 30. Data from all participants who received at least one dose of study drug were used to analyse efficacy and safety. This completed trial is registered with ClinicalTrials.gov (NCT05260021). Between April 12, 2022, and Dec 27, 2023, 146 participants were screened, of whom 99 (60 [61%] female, 39 [39%] male; mean age 14·7 years [SD 1·8]; mean baseline HbA_1c 8·04% [1·23]) were randomly assigned to tirzepatide 5 mg (n=32), tirzepatide 10 mg (n=33), or placebo (n=34). At week 30, tirzepatide was superior to placebo in reducing HbA_1c, with a mean reduction of 2·23% in the pooled tirzepatide group versus an increase of 0·05% in the placebo group (estimated treatment difference -2·28%; 95% CI -2·87 to -1·69; p<0·0001). Glycaemic efficacy was sustained up to 52 weeks with tirzepatide treatment. Tirzepatide also resulted in significant reductions in BMI of 7·4% and 11·2% for the 5 mg and 10 mg groups, respectively, compared with 0·4% in the placebo group at 30 weeks. The most common adverse events with tirzepatide treatment were gastrointestinal, all mild to moderate in severity, and decreased over time. Two (6%) patients in the tirzepatide 5 mg group discontinued study drug due to an adverse event. The safety profile of tirzepatide was consistent with that reported in adults. No deaths were reported during the study period. Tirzepatide demonstrated significant improvements in glycaemic control and BMI compared with placebo. These effects were sustained over 1 year. Eli Lilly and Company.