Efficacy and safety of once-weekly tirzepatide in Japanese participants with type 2 diabetes who have obesity or overweight: Subpopulation analysis of the SURMOUNT-2 trial

Diabetes Obes Metab. 2025 Aug;27(8):4557-4566. doi: 10.1111/dom.16500. Epub 2025 Jun 9.

Abstract

Aim: To assess the efficacy and safety of once-weekly tirzepatide in Japanese participants with obesity and type 2 diabetes (T2D).

Materials and methods: This subpopulation analysis of 41 Japanese participants from three clinical trial sites in the SURMOUNT-2 trial evaluated the efficacy and safety of tirzepatide as an adjunct to lifestyle interventions in adults with body mass index ≥27 kg/m2 and a diagnosis of T2D with glycated haemoglobin ≥7% to ≤10%. Coprimary endpoints were mean percent change in body weight and proportion of participants who achieved ≥5% body weight reduction at week 72. Percent change in body weight was compared between tirzepatide and placebo using a mixed model for repeated measures.

Results: The mean percent change (standard error) in body weight from baseline to week 72 was statistically significantly greater for both tirzepatide 10 mg (p = 0.001) and 15 mg (p = 0.013) compared with placebo: -12.4% (1.8%) and -10.2% (1.8%), respectively, compared with -3.5% (1.8%). At week 72, 85.7% and 78.6% of participants in the tirzepatide 10 mg and 15 mg groups, respectively, had a body weight reduction of ≥5%, versus 46.2% of participants receiving placebo. Reductions in glycemic parameters, waist circumference and systolic blood pressure, as well as numerical improvements in the lipid profile, were also observed with tirzepatide. No new safety concerns were identified.

Conclusions: In Japanese adults with obesity and T2D, once-weekly treatment with tirzepatide (10 or 15 mg) demonstrated significant reductions in body weight compared with placebo, with the safety profile generally consistent with previous studies.

Keywords: Japan; obesity; tirzepatide; type 2 diabetes.

Publication types

  • Randomized Controlled Trial
  • Multicenter Study

MeSH terms

  • Adult
  • Aged
  • Anti-Obesity Agents* / administration & dosage
  • Anti-Obesity Agents* / adverse effects
  • Blood Glucose
  • Body Mass Index
  • Diabetes Mellitus, Type 2* / blood
  • Diabetes Mellitus, Type 2* / complications
  • Diabetes Mellitus, Type 2* / drug therapy
  • Double-Blind Method
  • Drug Administration Schedule
  • East Asian People
  • Female
  • Glycated Hemoglobin / analysis
  • Humans
  • Hypoglycemic Agents* / administration & dosage
  • Hypoglycemic Agents* / adverse effects
  • Japan / epidemiology
  • Male
  • Middle Aged
  • Obesity* / complications
  • Obesity* / drug therapy
  • Overweight* / complications
  • Overweight* / drug therapy
  • Tirzepatide / administration & dosage
  • Treatment Outcome
  • Weight Loss / drug effects

Substances

  • Tirzepatide
  • Glycated Hemoglobin
  • Blood Glucose
  • Anti-Obesity Agents
  • Hypoglycemic Agents

Supplementary concepts

  • Japanese people

Grants and funding