SURPASS-CN-MONO published, completing tirzepatide's China registration package

A study called SURPASS-CN-MONO has been published, reporting results from a phase 3 trial of tirzepatide used alone, without other diabetes drugs, in 206 adults in China with early type 2 diabetes.^[1] Tirzepatide is sold in the United States as Mounjaro for diabetes and Zepbound for weight management. The trial is described as completing tirzepatide's China registration package, though the study itself does not detail what regulatory steps remain.^[1]

The trial ran for 40 weeks at 29 centers in China. Patients had not taken any diabetes medication in the prior 90 days. They were randomly split into four groups: once-weekly tirzepatide at 5 mg, 10 mg, or 15 mg, or a placebo.^[1] Group sizes were 52, 51, 52, and 51 patients.^[1]

At week 40, average blood sugar control, measured by HbA1c, dropped by 2.17, 2.06, and 2.15 percentage points in the 5 mg, 10 mg, and 15 mg groups, compared with just 0.13 points in the placebo group.^[1] That means tirzepatide lowered HbA1c by 1.93 to 2.04 percentage points more than placebo, depending on dose, and the difference was statistically significant at every dose.^[1]

Weight loss followed a similar pattern. Patients on 5 mg and 10 mg tirzepatide lost about 6.0 and 6.1 kilograms (roughly 13 to 13.5 pounds) more than the placebo group, while those on the highest dose, 15 mg, lost 9.7 kilograms (about 21 pounds) more than placebo, which itself averaged a 1.0-kilogram loss.^[1] All differences were statistically significant.^[1]

The most common side effects were gastrointestinal, a pattern seen in earlier tirzepatide trials.^[1] Notably, none of the tirzepatide groups had clinically significant low blood sugar, defined as a blood glucose reading under 54 mg/dL, or severe hypoglycemia.^[1] The study's authors, who work for Eli Lilly, the drug's maker and funder of the trial, concluded that the safety profile matched prior tirzepatide studies.^[1]

Why it matters for patients

This trial was conducted in China, not the United States, and enrolled people with early type 2 diabetes who had not yet started any diabetes medication.^[1] The results add to the body of evidence supporting tirzepatide's effects on blood sugar and weight when used by itself, without background insulin or other diabetes drugs.^[1] For US patients already using Mounjaro or Zepbound, or considering them, this trial does not change current US labeling or dosing. It is one more data point showing consistent effects across different patient populations, since the drug has mostly been studied in trials outside China until now.

The absence of clinically significant hypoglycemia is a practical detail for anyone weighing GLP-1/GIP therapies against other diabetes drugs that carry a higher risk of dangerously low blood sugar.^[1] Still, gastrointestinal side effects, the most commonly reported issue in this trial, remain a known tradeoff that patients report with tirzepatide in other markets as well.^[1]

What happens next

The source does not specify a timeline for Chinese regulatory approval or say whether US labeling changes are expected as a result of this trial.^[1] The study was funded by Eli Lilly, and its registration number is listed as NCT05963022.^[1] Details on any further regulatory action, in China or elsewhere, are not yet known from the published report.