SURPASS-PEDS results presented and published

Eli Lilly presented full results from SURPASS-PEDS on September 17, 2025, at the European Association for the Study of Diabetes annual meeting, with simultaneous publication in The Lancet ^[2][3]. It is the first Phase 3 trial of tirzepatide (sold as Mounjaro for type 2 diabetes and Zepbound for obesity) in children and adolescents with type 2 diabetes ^[2].

The trial ran at 39 sites in eight countries — the US, Australia, Brazil, India, Israel, Italy, Mexico and the United Kingdom ^[1][2]. Between April 12, 2022, and December 27, 2023, 146 people were screened and 99 were randomly assigned to tirzepatide 5 mg (32), tirzepatide 10 mg (33) or placebo (34) ^[1]. All were ages 10 to under 18 with diabetes not adequately controlled on metformin, basal insulin or both ^[2]. Participants averaged 14.7 years old, 61% were female, and mean baseline HbA1c was 8.04% with a mean BMI of about 35 kg/m² and mean weight of 96.6 kg (about 213 lb) ^[1][2]. The double-blind period lasted 30 weeks, followed by a 22-week open-label extension in which everyone received tirzepatide ^[1].

The numbers, and why two sets exist

Under the trial's "efficacy estimand" — what would have happened if everyone had stayed on the assigned drug for 30 weeks without rescue medication ^[2] — pooled tirzepatide lowered HbA1c by 2.23% while placebo rose 0.05%, an estimated treatment difference of −2.28% (95% CI −2.87 to −1.69; p<0.0001) ^[1]. Under the "treatment-regimen estimand," which counts everyone regardless of whether they stopped the drug or added rescue medication ^[2], the changes were −2.0% for tirzepatide and −0.2% for placebo ^[2][4]. Mounjaro's FDA label reports the same trial under the treatment-regimen estimand as a least-squares mean difference of −1.8% (95% CI −2.4 to −1.2) ^[7]. Those are different ways of analyzing one dataset, not different trials.

Other 30-week results: 86.1% of the 10 mg group reached an A1C of 6.5% or lower, versus 27.8% on placebo (efficacy estimand) ^[2]. BMI fell 7.4% with 5 mg and 11.2% with 10 mg, versus 0.4% on placebo ^[1][2]. Fasting serum glucose dropped 53.5 mg/dL on 10 mg versus 7.9 mg/dL on placebo ^[2]. Lilly says A1C and BMI improvements continued through 52 weeks ^[2].

The most common side effects were gastrointestinal and all mild to moderate, occurring mainly during dose increases: diarrhea 25% of pooled tirzepatide patients versus 6% on placebo, nausea 20% versus 9%, and vomiting 14% versus 3% ^[2]. Two patients (6%) in the 5 mg group stopped the drug because of an adverse event; none did in the 10 mg group or on placebo ^[1][2]. No severe hypoglycemia and no deaths occurred ^[1][2]. Level 2 low blood sugar (under 54 mg/dL) was reported by 15.4% on tirzepatide versus 5.9% on placebo ^[2]. The Lancet published a correction notice for the paper on September 25, 2025 ^[1].

Why it matters for patients

Youth-onset type 2 diabetes tends to progress faster than adult-onset disease, and options beyond metformin and insulin have been limited ^[2]. This trial is the evidence base that supported expanding tirzepatide's use to younger patients: Lilly said in September 2025 it had submitted the results to global regulators ^[2], and Mounjaro's label now lists an indication for pediatric patients 10 years of age and older with type 2 diabetes, a change dated 12/2025 ^[7]. The label caps the pediatric dose at 10 mg once weekly, versus 15 mg for adults ^[7].

Some limits are worth keeping in mind. The trial enrolled only 99 people, ran 30 weeks blinded and 52 weeks total, and was funded by Lilly ^[1][2]. It measured A1C, BMI and glucose, not long-term complications. Whether the drug is covered for a given child, and at what cost, is not addressed in these sources.

What happens next

No further pediatric trial milestones are named in these sources. Lilly's ongoing tirzepatide studies in chronic kidney disease and obesity-related morbidity and mortality are in adults ^[2]. Mounjaro's label separately added a cardiovascular risk-reduction indication for adults in August 2026 ^[6][7].