SURMOUNT-CN reports China obesity trial results in JAMA

A new clinical trial called SURMOUNT-CN found that tirzepatide, the drug sold in the US as Mounjaro and Zepbound, led to significant weight loss in Chinese adults with obesity or overweight over 52 weeks. The results, published in JAMA, showed average weight reductions of 13.6% with the 10-mg dose and 17.5% with the 15-mg dose, compared with 2.3% for placebo ^[1].

The study enrolled 210 adults across 29 centers in China between September 2021 and December 2022 ^[1]. Participants had a body mass index (BMI) of 28 or higher, or 24 or higher with at least one weight-related health condition, not including diabetes ^[1]. They were randomly split into three groups: 70 people received 10 mg of tirzepatide weekly, 71 received 15 mg, and 69 received placebo, all alongside lifestyle counseling ^[1]. The average participant was 36 years old and weighed about 92 kilograms (roughly 202 pounds) at the start, with an average BMI of 32.3 ^[1].

By week 52, 87.7% of people on the 10-mg dose and 85.8% of those on the 15-mg dose lost at least 5% of their body weight, compared with just 29.3% of those on placebo ^[1]. The differences between each tirzepatide dose and placebo were statistically significant ^[1]. Most side effects were gastrointestinal, described as mild to moderate, and fewer than 5% of participants stopped treatment because of side effects ^[1]. Of the 210 people enrolled, 201 (95.7%) completed the trial ^[1].

An erratum was later issued correcting errors in the paper's figure, results section, and end matter, though the specific corrections are not detailed in the source material reviewed here ^[1]. Two published commentaries accompanying the study description the findings as meaningful evidence for treating obesity in China, one calling it a signal with implications for the broader global obesity epidemic ^[1].

Why it matters for patients

This trial adds tirzepatide data from a Chinese population to a drug already approved and widely used in the United States under the brand names Mounjaro and Zepbound. The weight-loss percentages in this study are in a similar range to what US-based tirzepatide trials have shown in other populations, though this article's sources do not include a direct numerical comparison to US trial results.

For US patients, the study is a reminder that tirzepatide's effects have now been tested in multiple populations and settings, which can help doctors and regulators understand how consistent the drug's benefits and risks are across different groups of people. The side effect pattern found here, mostly gastrointestinal and mostly mild to moderate, matches what has been reported in other tirzepatide research, though this source does not compare discontinuation rates directly to other trials.

It's not yet known from these sources whether this specific trial will directly affect tirzepatide's approval status, labeling, or availability in the US. The trial was conducted to support regulatory needs in China, and the sources do not say whether the U.S. Food and Drug Administration has reviewed or plans to review this data.

What happens next

The trial was registered with the identifier NCT05024032, but the sources here do not specify further steps, such as regulatory filings in China or elsewhere, that may follow this publication ^[1]. Readers interested in how this data might affect future guidance or labeling in the US will need to watch for separate FDA actions, which are not addressed in the available sources.