Hengrui and Kailera report 19.2% weight loss at 48 weeks for dual GLP-1/GIP drug HRS9531
The results add another late-stage dual GLP-1/GIP candidate, but the drug is not approved in the US and no head-to-head comparison with marketed obesity medicines has been reported.
On November 4, 2025, Hengrui Pharma and Kailera Therapeutics presented additional Phase 3 data at ObesityWeek 2025 showing that HRS9531, an investigational once-weekly injectable dual GLP-1/GIP receptor agonist, produced a mean weight loss of 19.2% at the 6 mg dose over 48 weeks, with no plateau in weight loss and a safety profile described as consistent with other GLP-1-based treatments [1].
The trial, called GEMINI-1 (NCT06396429), was run by Hengrui in China. It enrolled 567 adults age 18 and older with obesity (BMI of at least 28) or overweight (BMI of at least 24) plus at least one weight-related health condition, and without diabetes. Mean starting body weight was 93 kg (205 lb). Participants were randomly assigned in equal groups to once-weekly injections of HRS9531 at 2 mg, 4 mg, 6 mg, or placebo for 48 weeks; 531 participants completed the trial. The study met both of its co-primary endpoints, the companies said [1].
The companies reported results two ways. Under one analysis method, mean weight loss was 11.2% at 2 mg, 17.4% at 4 mg, and 19.2% at 6 mg, compared with 1.4% for placebo. Under a second method that counts participants regardless of whether they stayed on treatment, the figures were 10.7%, 16.4%, and 17.7%, again compared with 1.4% for placebo [1].
Looking at thresholds, 68.1% of participants on 2 mg, 88.0% on 4 mg, and 85.7% on 6 mg lost at least 5% of their body weight. Among those on 6 mg, 44.4% lost at least 20% [1]. The companies also reported improvements in blood pressure, lipids, measures of insulin resistance, and hsCRP, a marker of inflammation [1].
Most treatment-emergent side effects were mild to moderate and gastrointestinal, the companies said. Permanent discontinuation because of side effects was low: 0.7% (1 participant) at 2 mg, 0.7% (1 participant) at 4 mg, 1.4% (2 participants) at 6 mg, and 0% on placebo [1].
Hengrui has submitted a marketing application to China's National Medical Products Administration for chronic weight management in adults, and the filing has been accepted for review [1]. In an earlier Phase 2 trial, the 8 mg dose produced 23.6% mean weight loss (21.7% when adjusted for placebo) at week 36, also with no plateau [1].
Why it matters for patients
HRS9531 is not approved anywhere, including the United States, and is not available outside clinical trials. The Chinese filing has been accepted for review, not cleared, so no decision has been disclosed [1].
Like tirzepatide (Mounjaro, Zepbound), HRS9531 targets both the GLP-1 and GIP receptors, the same two-hormone approach used by one of the most effective obesity drugs on the US market [1]. Another late-stage candidate in that class could eventually mean more competition in a category where supply, insurance coverage, and price have shaped access.
How HRS9531 compares with semaglutide (Ozempic, Wegovy, Rybelsus) or tirzepatide is not known. No head-to-head trial against either drug has been reported, so the 19.2% figure cannot be lined up directly against results from other trials, which used different designs, populations, and analysis methods [1].
The GEMINI-1 results come from adults in China without diabetes, so whether they carry over to a broader population, including people with type 2 diabetes, has not been established [1].
Nothing has been disclosed about US pricing, insurance coverage, or a US filing timeline [1].
What happens next
Kailera, which holds rights to develop the drug outside Greater China as KAI-9531, says it plans to start a global Phase 3 program by the end of 2025. That program includes three trials: one in adults with a BMI above 30, or above 27 with at least one other condition, and without type 2 diabetes; one in adults with a BMI above 27 and type 2 diabetes; and one in adults with a BMI above 35 and without type 2 diabetes [1].
The global trials will test maintenance doses of 8 mg and 10 mg and at least 52 weeks of maintenance dosing, longer and higher than what was studied in GEMINI-1 [1].
"We're excited to start our global Phase 3 program by year-end to evaluate both higher doses and longer treatment durations to unlock the full potential of KAI-9531," said Ron Renaud, president and chief executive officer of Kailera [1]. Hong Chen, head of the metabolism department at Hengrui Pharma, said the company believes HRS9531 "has the potential to make a meaningful difference in the lives of people living with obesity" [1].
More than 2,000 patients have received HRS9531 across Phase 1, Phase 2, and Phase 3 trials in China to date, according to the companies [1].
Sources
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