STEP 12: Semaglutide 2.4 mg in Chinese and Taiwanese Adults with Overweight or Obesity

The STEP trial program has generated most of the placebo-controlled evidence behind semaglutide’s weight-management research profile, but the earlier trials in that program were conducted almost entirely in North American and European populations using the WHO’s standard BMI ≥30 kg/m² threshold for obesity. STEP 12, published this month in The Lancet Diabetes & Endocrinology, is the first STEP-program trial run specifically in mainland China and Taiwan, and it uses BMI thresholds calibrated to those populations rather than importing the Western cutoff wholesale.

Trial design, briefly

STEP 12 was a randomised, double-blind, placebo-controlled, phase 3b trial conducted at 19 sites across mainland China and Taiwan. Because East Asian populations tend to reach comparable metabolic risk at lower BMI than Western populations, the trial enrolled adults using locally defined thresholds: a BMI of 24 to under 28 kg/m² with at least one weight-related comorbidity, or a BMI of 28 to under 30 kg/m², with or without type 2 diabetes. Participants were randomly assigned 2:1 to once-weekly subcutaneous semaglutide 2.4 mg or placebo, both alongside a lifestyle intervention, for 44 weeks. Coprimary endpoints were percentage change in bodyweight and the proportion of participants reaching at least 5% bodyweight reduction. The trial is registered at ClinicalTrials.gov (NCT06041217) and has completed.

What the trial found

Of 254 people screened, 242 were randomised — 161 to semaglutide and 81 to placebo. Half the participants were female, and about one in five had type 2 diabetes at baseline. Bodyweight reduction was substantially greater with semaglutide than placebo: -12.1% versus -2.2%, an estimated treatment difference of -9.9 percentage points (95% CI -11.8 to -8.0; p<0.0001). On the second coprimary endpoint, 80.5% of the semaglutide group reached at least 5% bodyweight reduction versus 24.4% on placebo (odds ratio 14.8; 95% CI 7.4 to 29.6). Adverse events were more common in the semaglutide arm (87.6% versus 75.3%), with gastrointestinal disorders the most frequently reported category — consistent with the safety pattern already established for semaglutide and for GLP-1 receptor agonists as a drug class more broadly.

Why the population matters

A large share of the existing semaglutide efficacy data was generated in trial populations screened against a BMI ≥30 kg/m² cutoff, which doesn’t map cleanly onto how obesity-related metabolic risk presents in East Asian populations — health authorities in the region have generally used lower BMI thresholds precisely because comorbidity risk rises earlier on the BMI scale. STEP 12 is notable less for its topline effect size, which lands in a similar range to earlier STEP trials, and more for confirming that effect size holds up when the enrollment criteria themselves are adjusted to reflect regional risk thresholds rather than applying a Western-derived cutoff to a different population.

What this means for ongoing research

STEP 12 was funded by Novo Nordisk, semaglutide’s manufacturer, which is standard for phase 3b registrational-style trials and is disclosed in the published paper. Like the rest of the STEP program, this is population-level trial data collected under close clinical supervision over a fixed 44-week window — it describes average outcomes in a controlled research setting, not a personal treatment prediction. Semaglutide remains available as an FDA-approved prescription medication under the Ozempic and Wegovy brand names; the research-grade material referenced on this site is a separate, unapproved-source item supplied strictly for use by licensed and trained professionals operating within their applicable regulations.

Further reading

• Guo L, Bao X, Huang KC, et al. “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.” The Lancet Diabetes & Endocrinology, 2026. PubMed: 42575111 · doi.org/10.1016/S2213-8587(26)00133-6