Ribupatide (HRS9531): The GLP-1/GIP Rival From China
Ribupatide delivered 19.2% weight loss in a Chinese Phase 3 trial and is now in global Phase 3 against semaglutide. What the data show — and what they don't.
Medically Reviewed
Reviewed by Dr. James Chen, MD, PhD, FACE on July 27, 2026
Our medical review process ensures clinical accuracy and patient safety.
Ribupatide is a once-weekly injectable dual GLP-1/GIP receptor agonist that has quietly become the most clinically advanced obesity drug in its class outside of Lilly and Novo Nordisk. Developed as HRS9531 by Jiangsu Hengrui Pharmaceuticals in China and licensed to US-based Kailera Therapeutics as KAI-9531, it has already completed a 48-week Phase 3 trial in China, has an NDA filed there, and entered a three-trial global Phase 3 program in January 2026 — one arm of which puts it head-to-head against semaglutide 2.4 mg.
The efficacy figures are large enough to demand attention and unusual enough in their provenance to demand scrutiny. Every efficacy number ribupatide has produced to date comes from trials run in China, in Chinese participants, at doses lower than the ones now being tested worldwide.
What Ribupatide Is and Where It Came From
Ribupatide is a peptide engineered to activate two incretin receptors at once: GLP-1 and GIP. That is the same mechanism as tirzepatide, the molecule behind Mounjaro and Zepbound, and the same mechanism Roche is pursuing with CT-388. It is administered by weekly subcutaneous injection.
The dual-receptor rationale is well established. GLP-1 agonism suppresses appetite and slows gastric emptying; GIP agonism appears to contribute through complementary routes and — more usefully — may soften the gastrointestinal burden that limits how far the GLP-1 arm can be pushed.
Evidence: "GIP receptor agonism enhances the weight-lowering efficacy of GLP-1 through complementary actions on adipose tissue function, nutrient partitioning, and central pathways regulating energy balance, and may also improve the gastrointestinal tolerability of GLP-1 receptor agonism." — Samms RJ, Coghlan MP, Sloop KW. Trends in Endocrinology & Metabolism. 2020;31(6):410-421. DOI: 10.1016/j.tem.2020.02.006
The commercial structure matters for reading the data. Hengrui developed the molecule and ran every trial that has reported efficacy so far. In 2024 it licensed rights outside Greater China to Kailera, a company created around this asset. More than 2,500 participants have received ribupatide across the program, with exposure out to 52 weeks.
The Chinese Phase 3 Result: Up to 19.2% at 48 Weeks
HRS9531-301 randomized 567 Chinese adults with obesity to once-weekly ribupatide at 2 mg, 4 mg, or 6 mg, or to placebo, for 48 weeks. 531 participants completed. Mean baseline body weight was 93 kg.
At the top dose the trial reported mean weight loss of 17.7% under the treatment-regimen estimand — 16.3% after subtracting placebo — and 19.2% under the efficacy estimand, or 17.7% placebo-adjusted. The two numbers answer different questions: the first is how well the drug works when prescribed, counting everyone who was randomized regardless of whether they stayed on it; the second is how well it works in people who actually take it. Cross-trial comparisons are only meaningful when the estimands match, a caveat that gets dropped from nearly every press release in this field.
Responder rates and the shape of the curve
| Outcome (48 weeks, top dose) | Ribupatide |
|---|---|
| Mean weight loss (efficacy estimand) | 19.2% |
| Mean weight loss (treatment-regimen estimand) | 17.7% |
| Placebo-adjusted (efficacy estimand) | 17.7% |
| ≥5% weight loss | 88.0% |
| ≥20% weight loss | 44.4% |
Nearly half of participants at the top dose lost a fifth of their body weight in under a year. The company also reports no plateau at week 48 — the curve was still descending when the trial ended, which means 6 mg has not found its ceiling. Safety was characterized as consistent with the GLP-1 class, with adverse events predominantly mild-to-moderate and gastrointestinal. Dose-level discontinuation rates were not disclosed, which is a meaningful gap for a drug whose entire commercial case rests on tolerability at high doses.
An earlier Phase 2 trial pushed to 8 mg and reported 23.6% weight loss at 36 weeks versus roughly 1.8% on placebo, despite only 12 of those 36 weeks being spent at the top dose. That figure is the one Kailera cites most often, and it is the reason the global program is testing 8 mg and 10 mg rather than stopping at 6 mg.
Does a Chinese Trial Predict a Global One?
This is the question that decides whether ribupatide's numbers survive contact with Western populations, and it deserves a real answer rather than the reflexive assumption that goes both ways in this debate.
Chinese trial participants in these studies weighed a mean of 93 kg at baseline. Participants in SURMOUNT-1, tirzepatide's pivotal global obesity trial, averaged roughly 105 kg. Because weight loss in this class is expressed as a percentage, differences in baseline weight, body composition, and visceral fat distribution can move the headline figure without any difference in the drug.
The empirical record on this is genuinely mixed, which is the useful part. In STEP 6, semaglutide 2.4 mg produced 13.2% mean weight loss at 68 weeks in Japanese and Korean adults.
Evidence: "Estimated mean change in bodyweight from baseline to week 68 was −13·2% with semaglutide 2·4 mg, −9·6% with semaglutide 1·7 mg, and −2·1% with placebo." — Kadowaki T, Isendahl J, Khalid U, et al. Lancet Diabetes & Endocrinology. 2022;10(3):193-206. DOI: 10.1016/S2213-8587(22)00008-0
That is lower than the 14.9% semaglutide 2.4 mg produced in the global STEP 1 trial, not higher. But SURMOUNT-J, tirzepatide's Japanese Phase 3, reported 22.7% at 15 mg over 72 weeks — modestly higher than the 20.9% seen in SURMOUNT-1.
Evidence: "The mean percent change in bodyweight from baseline to week 72 was −17·8% in the tirzepatide 10 mg group and −22·7% in the tirzepatide 15 mg group, compared with −1·7% in the placebo group." — Kadowaki T, et al. Lancet Diabetes & Endocrinology. 2025;13(5):384-396. DOI: 10.1016/S2213-8587(24)00377-2
East Asian trial populations have not systematically inflated percentage weight loss for incretin drugs. The direction of the difference varies by molecule and by trial. That is a mildly favorable read for ribupatide — it removes the easy dismissal — without being evidence that its specific numbers will replicate.
Kailera's own Phase 1 study addressed the pharmacology directly rather than the outcomes. In 49 adults in Australia given a single subcutaneous dose, exposure was similar between participants of Asian and non-Asian descent once adjusted for body weight, and day-29 weight loss reached 5.5% at 3 mg versus 0.4% on placebo. Comparable pharmacokinetics is a necessary condition for the efficacy to translate. It is not a sufficient one.
The KaiNETIC Global Phase 3 Program
Kailera randomized the first participants in KaiNETIC in January 2026. Three trials, all double-blind and placebo-controlled, all running 76 weeks with up to 24 weeks of titration and at least 52 weeks of maintenance dosing, enrolling across North America, Europe, the UK, Oceania, and South America.
| Trial | N (approx.) | Population | Doses | Primary endpoint |
|---|---|---|---|---|
| KaiNETIC-1 | 1,800 | BMI ≥30, or ≥27 with comorbidity; no T2D | 4, 6, 8, 10 mg or placebo | % weight change at week 76 |
| KaiNETIC-2 | 1,700 | BMI ≥27 with type 2 diabetes | 4, 6, 8, 10 mg or placebo | % weight change + HbA1c at week 76 |
| KaiNETIC-3 | 1,200 | BMI ≥35, no T2D | 8, 10 mg, placebo, or open-label semaglutide 2.4 mg | % weight change vs placebo and vs semaglutide |
KaiNETIC-3 is the trial that matters most. Running an active comparator against semaglutide 2.4 mg in participants with BMI ≥35 is a deliberate bet: the sponsor is claiming superiority over the current standard in the population with the most weight to lose, and an open-label arm means the result will be read as definitive if it lands and unignorable if it does not. Lilly took the same risk with SURMOUNT-5 and won.
Evidence: "The mean percentage change in weight at week 72 was −20.2% with tirzepatide and −13.7% with semaglutide." — Aronne LJ, Horn DB, le Roux CW, et al. New England Journal of Medicine. 2025;393(1):26-36. DOI: 10.1056/NEJMoa2416394
A separate Phase 2b is exploring doses up to 20 mg, more than triple the highest dose ever tested in a completed Phase 3.
The Oral Version
Hengrui is also developing ribupatide as a once-daily pill, and the Phase 2 data were presented at ADA 2026. 166 adults with obesity, mean baseline weight 92.6 kg and BMI 33.3, were titrated over eight weeks to 10 mg, 25 mg, or 50 mg daily and followed to week 26.
| Dose | Weight loss at wk 26 | ≥15% weight loss | Nausea | Vomiting |
|---|---|---|---|---|
| 10 mg | 6.9% | 4.8% | 11.9% | 2.4% |
| 25 mg | 12.1% | 38.6% | 22.7% | 11.4% |
| 50 mg | 12.1% | 37.5% | 20.0% | 7.5% |
| Placebo | 2.3% | — | — | — |
Two observations. The dose-response flattens completely between 25 mg and 50 mg — doubling the dose bought nothing but a modest increase in vomiting, which suggests absorption, not receptor engagement, is the binding constraint. And no participant permanently discontinued for a gastrointestinal adverse event, which is a better tolerability signal than the raw nausea percentages imply.
At 12.1% over 26 weeks the oral trails the injection substantially, though it is broadly in the range of the oral small molecules like orforglipron. A peptide taken by mouth faces an absorption problem that a small molecule does not, and this dataset looks like that problem showing up on schedule.
How Ribupatide Fits the Field
| Drug | Receptors | Best reported weight loss | Status |
|---|---|---|---|
| Semaglutide 2.4 mg | GLP-1 | ~14.9% at 68 wks | Approved |
| Tirzepatide 15 mg | GLP-1 + GIP | ~20.9% at 72 wks | Approved |
| Ribupatide 6 mg | GLP-1 + GIP | 19.2% at 48 wks (Ph 3, China) | Global Phase 3 |
| CT-388 24 mg | GLP-1 + GIP (biased) | 22.5% placebo-adj. at 48 wks (Ph 2) | Phase 3 |
| Retatrutide 12 mg | GLP-1 + GIP + glucagon | ~24.2% at 48 wks (Ph 2) | Phase 3 |
Ribupatide's argument is not that it is mechanistically novel — it is not, and mazdutide has already demonstrated that a Chinese-developed incretin drug can reach the market on its home turf. The argument is timeline and dose headroom: a completed Phase 3, an NDA filed, 19.2% at a dose the company considers submaximal, and a global program testing nearly double that dose. If 6 mg produces 19.2% in 48 weeks with no plateau, 10 mg over 76 weeks is a plausible route into the low-to-mid twenties.
The counterargument is that these entries rarely arrive intact. Doses that look tolerable in a 567-person trial routinely produce discontinuation rates in the thousands-of-patients setting that force the label down a notch, and ribupatide has not yet disclosed the dose-level dropout data that would let anyone judge this in advance.
Key Takeaways
Ribupatide delivered up to 19.2% mean weight loss at 48 weeks in a Chinese Phase 3 trial, with 44.4% of top-dose participants losing at least 20% of body weight and no plateau at trial end. An earlier Phase 2 at 8 mg reached 23.6% at 36 weeks. It is the most advanced GLP-1/GIP dual agonist outside Lilly's portfolio.
Every efficacy figure so far comes from China, at doses below those now in global testing. The evidence that East Asian trials systematically overstate this class is weak — STEP 6 came in below its global counterpart while SURMOUNT-J came in above — but "not systematically biased" is a much weaker claim than "will replicate," and the KaiNETIC readouts are what settle it.
What to watch: whether the head-to-head against semaglutide in KaiNETIC-3 delivers separation on the scale SURMOUNT-5 produced; whether 8 mg and 10 mg are tolerable over 76 weeks in Western populations or whether nausea caps the achievable dose; and what the discontinuation rates look like once they are actually published. With a 76-week primary endpoint and first randomization in January 2026, pivotal data are unlikely before 2028. And whatever the number turns out to be, ribupatide will inherit the same unsolved problem as every drug in this class — weight regain after stopping is a feature of the biology, not of any particular molecule.
References
- Samms RJ, Coghlan MP, Sloop KW. How may GIP enhance the therapeutic efficacy of GLP-1? Trends in Endocrinology & Metabolism. 2020;31(6):410-421. DOI: 10.1016/j.tem.2020.02.006
- Kadowaki T, Isendahl J, Khalid U, et al. Semaglutide once a week in adults with overweight or obesity, with or without type 2 diabetes in an east Asian population (STEP 6): a randomised, double-blind, double-dummy, placebo-controlled, phase 3a trial. Lancet Diabetes & Endocrinology. 2022;10(3):193-206. DOI: 10.1016/S2213-8587(22)00008-0
- Kadowaki T, et al. Efficacy and safety of once-weekly tirzepatide in Japanese patients with obesity disease (SURMOUNT-J): a multicentre, randomised, double-blind, placebo-controlled phase 3 trial. Lancet Diabetes & Endocrinology. 2025;13(5):384-396. DOI: 10.1016/S2213-8587(24)00377-2
- Jastreboff AM, Aronne LJ, Ahmad NN, et al. Tirzepatide once weekly for the treatment of obesity (SURMOUNT-1). New England Journal of Medicine. 2022;387(3):205-216. DOI: 10.1056/NEJMoa2206038
- Aronne LJ, Horn DB, le Roux CW, et al. Tirzepatide as compared with semaglutide for the treatment of obesity (SURMOUNT-5). New England Journal of Medicine. 2025;393(1):26-36. DOI: 10.1056/NEJMoa2416394
- Wilding JPH, Batterham RL, Calanna S, et al. Once-weekly semaglutide in adults with overweight or obesity (STEP 1). New England Journal of Medicine. 2021;384(11):989-1002. DOI: 10.1056/NEJMoa2032183
- Jastreboff AM, Kaplan LM, Frías JP, et al. Triple-hormone-receptor agonist retatrutide for obesity — a phase 2 trial. New England Journal of Medicine. 2023;389(6):514-526. DOI: 10.1056/NEJMoa2301972
- Hengrui Pharma and Kailera Therapeutics. Phase 3 obesity trial in China of dual GLP-1/GIP receptor agonist HRS9531 (HRS9531-301); ribupatide clinical data presented at ADA 2026, including oral ribupatide Phase 2 (NCT06841445) and KAI-9531 Phase 1 SAD (NCT07044401); KaiNETIC global Phase 3 program. Company releases — company-reported data, not peer-reviewed.
Last updated: 2026-07-27 Medical review: Dr. James Chen, MD, PhD, FACE
Tags
Written By
Dr. Sarah Mitchell
Medical Director, MD, FACP
Dr. Sarah Mitchell is a board-certified internist specializing in metabolic medicine and weight management. With over 15 years of clinical experience, she has helped thousands of patients achieve sustainable weight loss through evidence-based approaches.
Medical Reviewer
Dr. James Chen
Endocrinologist, MD, PhD, FACE
Dr. James Chen is a fellowship-trained endocrinologist with expertise in diabetes, metabolism, and hormone-related weight disorders. His research on GLP-1 receptor agonists has been published in leading medical journals.
Editorial Standards
This article follows our strict editorial guidelines. All content is based on peer-reviewed research and reviewed by medical professionals. This information is for educational purposes only — always consult your healthcare provider before making medical decisions.