What Is Ribupatide (KAI-9531)? The Dual GIP/GLP-1 Peptide Now in Phase 3

The obesity-treatment pipeline is becoming increasingly crowded with next-generation incretin drugs.

One of the newer names moving rapidly through late-stage development is ribupatide, also known as KAI-9531.

Ribupatide is an investigational once-weekly dual GIP and GLP-1 receptor agonist peptide being developed for obesity and overweight.

What makes it particularly interesting is that the global Phase 3 programme is already fully enrolled — and one of those trials is directly comparing ribupatide with semaglutide. (Kailera Therapeutics⁠)

What Is Ribupatide?

Ribupatide, previously identified as KAI-9531, is an experimental peptide designed to activate two metabolic hormone receptors:

• GIP
• GLP-1

It is being developed by Kailera Therapeutics outside Greater China.

The compound is administered as a once-weekly subcutaneous injection.

Its overall strategy is similar in principle to other dual incretin agonists: combine two complementary hormonal signals within a single molecule.

What Does GLP-1 Do?

GLP-1 is a naturally occurring hormone released from the intestine after food is consumed.

It contributes to:

• appetite regulation
• satiety
• insulin secretion
• blood-glucose control
• slowing of gastric emptying

GLP-1 receptor agonism has already become a major therapeutic strategy in both diabetes and obesity.

What Does GIP Do?

GIP stands for glucose-dependent insulinotropic polypeptide.

It is another incretin hormone released after eating.

GIP contributes to insulin signalling and interacts with several tissues involved in nutrient metabolism.

Combining GIP and GLP-1 receptor activity has become an important area of obesity research because the two signals can potentially produce complementary metabolic effects.

How Does Ribupatide Work?

Ribupatide is designed to activate both the GIP receptor and GLP-1 receptor.

Rather than administering two separate drugs, both activities are engineered into a single peptide molecule.

Researchers are investigating whether this dual-receptor profile can produce substantial weight reduction while maintaining an acceptable tolerability profile.

Is Ribupatide Similar to Tirzepatide?

At the receptor level, yes.

Both ribupatide and tirzepatide target:

GIP + GLP-1

But they are different molecules.

They have different:

• structures
• receptor-activity profiles
• dosing programmes
• pharmacokinetic properties
• clinical-development programmes

Similar receptor targets do not guarantee identical clinical results.

That is why each drug needs to be evaluated independently.

Has Ribupatide Reached Phase 3?

Yes.

Ribupatide has entered a large global Phase 3 programme called KaiNETIC.

In September 2026, Kailera announced that enrolment had been completed across the programme.

The programme consists of three major Phase 3 studies:

• KaiNETIC-1
• KaiNETIC-2
• KaiNETIC-3

Together, they are evaluating ribupatide in more than 4,700 people living with obesity or overweight. (Kailera Therapeutics⁠)

Topline data are currently expected in mid-2028.

What Is KaiNETIC-3?

KaiNETIC-3 is particularly interesting because it is not only comparing ribupatide with placebo.

It is also comparing ribupatide directly with semaglutide.

The Phase 3 study is evaluating adults with obesity who do not have diabetes.

Its primary objective is to determine whether once-weekly ribupatide produces greater percentage body-weight reduction than both semaglutide and placebo. (ClinicalTrials⁠)

That makes this one of the more important upcoming head-to-head obesity trials.

How Large Is KaiNETIC-3?

The trial is enrolling roughly 1,200 to 1,270 participants, depending on the most recent registry update.

Participants receive ribupatide, semaglutide or placebo for approximately 76 weeks. (ClinicalTrials⁠)

The study began in December 2025 and is expected to complete in 2028.

What About People With Type 2 Diabetes?

KaiNETIC-2 is specifically evaluating ribupatide in adults living with obesity or overweight and diabetes.

The European trial record indicates planned enrolment of more than 1,200 participants.

The study is designed to investigate both:

• percentage body-weight change
• change in HbA1c

That will help researchers determine whether ribupatide can influence both body weight and glucose control in people with diabetes. (CTIS.eu⁠)

Are There Already Phase 3 Results?

There are already Phase 3 results from China involving ribupatide for type 2 diabetes.

In August 2026, Hengrui Pharma announced topline results from a Phase 3 study comparing ribupatide with semaglutide 1 mg in adults whose diabetes was inadequately controlled with oral medication.

Both ribupatide doses met the study’s main objective of demonstrating non-inferiority to semaglutide.

The 4 mg ribupatide group produced an average HbA1c reduction of up to approximately 2.78 percentage points, compared with 2.29 percentage points for semaglutide 1 mg. (Hengrui Medicine⁠)

These results relate primarily to glucose control rather than the global obesity programme.

Is Ribupatide Being Tested at Higher Doses?

Yes.

Kailera is also running a separate Phase 2b high-dose study in people with a BMI of 35 or higher without type 2 diabetes.

The trial is evaluating weekly doses of:

• 10 mg
• 13 mg
• 16 mg
• 20 mg

over 48 weeks.

Around 264 participants have been enrolled, with data expected in 2027. (Kailera Therapeutics⁠)

This study is intended to explore whether higher doses can produce greater weight reduction.

Is There an Oral Version of Ribupatide?

Yes, and this makes the programme considerably more interesting.

An oral formulation called ribupatide oral, or KAI-9531-T, is also being developed.

Kailera reported that a Phase 2 obesity study presented in 2026 found average weight reduction of up to approximately 12.1% after 26 weeks with oral doses of 25 mg and 50 mg.

The company reported that the weight-loss curve had not clearly plateaued by week 26. (Kailera Therapeutics⁠)

How Many People Achieved Larger Weight Loss With Oral Ribupatide?

In the same Phase 2 programme, Kailera reported that up to approximately 38.6% of participants achieved at least 15% weight reduction. (Kailera Therapeutics⁠)

Those are encouraging findings.

However, they remain Phase 2 results and need confirmation in larger trials.

Is Oral Ribupatide Moving Into Phase 3?

Yes.

Kailera has reported that its investigational new drug application for oral ribupatide is active with the US FDA.

The company plans to initiate global Phase 3 obesity trials for the oral formulation in the first half of 2027. (Kailera Therapeutics⁠)

That means ribupatide could eventually be developed in both injectable and tablet forms.

Why Is an Oral Dual Agonist Important?

Long-term obesity therapy presents a practical challenge.

Weekly injections work well for many people, but others may prefer tablets.

An effective oral dual agonist could potentially provide:

• greater convenience
• easier long-term use
• an alternative to injections
• different maintenance options

The oral formulation therefore gives ribupatide a broader development strategy than an injectable-only product.

What Were the Side Effects With Oral Ribupatide?

Gastrointestinal effects remain relevant, as they are with many incretin-based therapies.

In the Phase 2 oral study, Kailera reported vomiting in approximately:

• 11.4% of participants receiving 25 mg
• 7.5% receiving 50 mg

The company characterised the overall incidence of gastrointestinal adverse events as relatively low. (Kailera Therapeutics⁠)

Larger Phase 3 trials will provide a more reliable understanding of tolerability.

How Is Ribupatide Different From VK2735?

The two compounds have several similarities.

Both target:

GIP + GLP-1

Both are being developed for obesity.

And both have injectable and oral development programmes.

The difference will ultimately come down to their individual:

• efficacy
• tolerability
• dose requirements
• oral bioavailability
• maintenance potential
• long-term safety

Without direct comparative trials, it would be premature to declare one superior.

How Is Ribupatide Different From Survodutide?

Their second receptor differs.

Ribupatide targets:

GIP + GLP-1

Survodutide targets:

glucagon + GLP-1

This means the two compounds approach obesity through different combinations of metabolic pathways.

How Is Ribupatide Different From Retatrutide?

Retatrutide activates three receptors:

• GIP
• GLP-1
• glucagon

Ribupatide activates two:

• GIP
• GLP-1

Again, the number of receptors targeted does not automatically determine which medicine will perform better.

Receptor balance, potency, tolerability and pharmacokinetics all matter.

Why Is the Semaglutide Comparison Important?

Placebo-controlled trials tell researchers whether a treatment works better than no active drug.

But the obesity market now contains highly effective established therapies.

That means a new treatment increasingly needs to answer another question:

Does it improve on what is already available?

KaiNETIC-3 is attempting to answer that directly by comparing ribupatide against semaglutide.

If ribupatide demonstrates superior average weight reduction with acceptable tolerability, that could significantly influence its future positioning.

Is Ribupatide Approved?

No.

Ribupatide remains an investigational medicine.

It is not currently an established approved obesity treatment outside the clinical-development process.

The global Phase 3 programme still needs to demonstrate long-term efficacy and safety.

What Still Needs to Be Answered?

Important unanswered questions include:

• how much average weight reduction occurs at 76 weeks
• whether ribupatide outperforms semaglutide
• how it compares with other dual agonists
• long-term gastrointestinal tolerability
• cardiovascular outcomes
• effects on lean mass
• whether higher doses provide additional benefit
• whether oral ribupatide can reproduce injectable efficacy
• long-term safety

The Phase 3 results expected in 2028 should answer many of these questions.

Why Is Ribupatide Worth Watching?

Ribupatide is interesting because it is no longer simply an early experimental peptide.

Its global Phase 3 programme is already fully enrolled.

More importantly, the programme includes a direct active comparison against one of the best-known GLP-1 therapies.

That moves the scientific question from:

“Does another GIP/GLP-1 agonist work?”

to:

“Can this particular dual agonist meaningfully outperform established therapy?”

The Bottom Line

Ribupatide, or KAI-9531, is an investigational once-weekly dual GIP/GLP-1 receptor agonist peptide being developed for obesity and metabolic disease.

Its global KaiNETIC Phase 3 programme has completed enrolment across three trials involving more than 4,700 participants, with topline results expected in mid-2028. (Kailera Therapeutics⁠)

Most importantly, KaiNETIC-3 is directly comparing ribupatide against semaglutide and placebo in adults with obesity without diabetes. (ClinicalTrials⁠)

An oral formulation is also progressing, after Phase 2 research reported average weight reduction of up to approximately 12.1% at 26 weeks. (Kailera Therapeutics⁠)

That combination of late-stage injectable development, an oral programme and a direct semaglutide comparison makes ribupatide one of the more important emerging metabolic peptides to watch.

This article is for research and educational purposes only. Ribupatide remains investigational and is not presented as an approved or established treatment.