Efficacy and safety of once-weekly semaglutide 2·4 mg in Chinese adults with overweight or obesity (STEP 12): a randomised, double-blind, placebo-controlled, multicentre, phase 3b trial.

BACKGROUND: Semaglutide 2·4 mg is a GLP-1 receptor agonist that reduces bodyweight, and provides other cardiometabolic benefits, among people with a BMI at least 30 kg/m or at least 27 kg/m and with weight-related comorbidities. This trial aimed to evaluate the efficacy, tolerability, and safety of semaglutide 2·4 mg in adults from mainland China and Taiwan with overweight or obesity according to locally defined, BMI thresholds. METHODS: This completed randomised, double-blind, placebo-controlled, multicentre, two-armed, parallel-group, phase 3b trial (STEP 12) was conducted at 19 sites across mainland China and Taiwan. Adults with a BMI of 24-<28 kg/m and at least one weight-related comorbidity, or a BMI of 28-<30 kg/m, with or without type 2 diabetes, were randomly assigned (2:1) to once-weekly subcutaneous semaglutide 2·4 mg or placebo, plus lifestyle intervention, for 44 weeks. Randomisation was performed by the study sponsor using the Randomisation Trial Supplies Management System. Coprimary endpoints were percentage change in bodyweight and the proportion of participants achieving at least 5% bodyweight reduction. Safety was analysed descriptively in all participants who received the trial intervention. Missing data at week 44 were imputed with washout multiple imputation. This study is registered with ClinicalTrials.gov, NCT06041217, and is completed. FINDINGS: Between Sept 15, 2023, and May 7, 2025, of 254 screened participants, 161 (66·5%) of 242 participants were randomly assigned to semaglutide 2·4 mg and 81 (33·5%) to placebo; 121 (50·0%) participants were female, and 47 (19·4%) participants had type 2 diabetes. Bodyweight reduction was greater with semaglutide versus placebo (-12·1% [SE 0·6] vs -2·2% [0·8]; estimated treatment difference -9·9 percentage points [95% CI -11·8 to -8·0]; p<0·0001), with a greater proportion of participants achieving at least 5% bodyweight reduction (80·5% vs 24·4%; odds ratio [OR] 14·8 [95% CI 7·4 to 29·6]; p<0·0001). Adverse events were reported in 141 (87·6%) of 161 participants in the semaglutide 2·4 mg group and 61 (75·3%) of 81 participants in the placebo group, with gastrointestinal disorders being the most common. INTERPRETATION: Semaglutide 2·4 mg provided a superior reduction in bodyweight versus placebo in Chinese adults with overweight or obesity. The safety profile was consistent with the known profile of semaglutide. FUNDING: Novo Nordisk A/S. TRANSLATION: For the Mandarin translation of the abstract see Supplementary Materials section.