Cagrilintide vs Petrelintide vs Eloralintide: How Do the New Amylin Peptides Differ?

Amylin has become one of the fastest-moving areas in metabolic peptide research.

Three names now appear repeatedly:

• cagrilintide
• petrelintide
• eloralintide

All three are designed around the amylin pathway.

But they are not the same type of drug.

Cagrilintide and petrelintide are long-acting amylin analogues, while eloralintide is a selective amylin receptor agonist designed to preferentially activate the AMY1 receptor.

That difference could ultimately influence:

• appetite control
• tolerability
• receptor selectivity
• combination strategies
• body composition
• how each compound is used alongside GLP-1 or GIP/GLP-1 therapies

By late 2026, petrelintide and eloralintide had both progressed into Phase 3 development, while cagrilintide had generated extensive late-stage evidence through the CagriSema programme. (Zealand Pharma⁠)

First: What Is Amylin?

Amylin is a naturally occurring peptide hormone released from pancreatic beta cells alongside insulin.

It helps regulate:

• satiety
• meal size
• meal termination
• gastric emptying
• post-meal glucagon

Its role in signalling fullness makes it particularly interesting for obesity research.

The goal of modern amylin drugs is essentially to reproduce or refine this natural signal while making it last long enough for practical treatment.

What Is Cagrilintide?

Cagrilintide is a long-acting amylin analogue developed by Novo Nordisk.

It has become best known as one half of:

CagriSema

which combines:

cagrilintide + semaglutide

or:

amylin + GLP-1

Cagrilintide is therefore currently one of the strongest examples of amylin being used as a partner pathway rather than simply as standalone therapy.

Why Has Cagrilintide Become So Important?

Because CagriSema has now generated large Phase 3 datasets.

Novo Nordisk’s REDEFINE programme includes several thousand participants across trials investigating:

• obesity
• type 2 diabetes
• cardiovascular outcomes
• body composition
• long-term maintenance

The programme includes a 7,000-participant cardiovascular-outcomes study and dedicated trials examining body composition and weight maintenance. (Novo Nordisk⁠)

That gives cagrilintide a very mature clinical evidence base compared with many newer amylin compounds.

What Is Petrelintide?

Petrelintide is another long-acting amylin analogue.

It was previously known as ZP8396.

Zealand Pharma and Roche are developing it as a once-weekly therapy for obesity and overweight.

Unlike cagrilintide, which has become strongly associated with CagriSema, petrelintide is being developed prominently as an amylin-first standalone treatment.

The Phase 3 ZUPREME programme was initiated in September 2026. (Zealand Pharma⁠)

What Did Petrelintide’s Phase 2 Trial Show?

The ZUPREME-1 Phase 2 trial investigated petrelintide in people with obesity or overweight without type 2 diabetes.

The peer-reviewed results were published in The Lancet Diabetes & Endocrinology in 2026. (PubMed⁠)

The trial provided evidence that a long-acting amylin analogue can produce clinically meaningful weight reduction as monotherapy.

That is an important distinction.

It suggests the amylin pathway does not necessarily need GLP-1 activity to produce substantial effects.

What Is Petrelintide Being Combined With?

This is where petrelintide becomes particularly interesting.

Zealand and Roche are also developing a fixed-dose combination involving:

petrelintide + CT-388

CT-388 is Roche’s dual:

GLP-1 + GIP receptor agonist.

That means the combination brings together:

amylin + GLP-1 + GIP

Zealand describes the programme as being aimed at people who may need greater weight-loss efficacy or enhanced glycaemic control beyond amylin monotherapy. (Zealand Pharma⁠)

What Is Eloralintide?

Eloralintide is different again.

Previously known as LY3841136, it is being developed by Eli Lilly as a once-weekly selective amylin receptor agonist.

Lilly states that it is designed to preferentially activate the:

AMY1 receptor. (Lilly⁠)

That means eloralintide is not simply trying to reproduce every aspect of natural amylin signalling equally.

It represents a more selective pharmacological strategy.

Why Might Selective Amylin Signalling Matter?

Amylin interacts with several receptor complexes.

Different receptor subtypes may contribute differently to:

• satiety
• nausea
• food intake
• neural signalling

Researchers are therefore investigating whether selective activation could preserve desirable appetite effects while producing a different tolerability profile.

That is still a hypothesis being tested clinically.

Has Eloralintide Reached Phase 3?

Yes.

The Phase 3 ENLIGHTEN-1 trial is enrolling around 1,980 adults with obesity or overweight without type 2 diabetes.

The study evaluates weekly eloralintide over an extended treatment period. (Lilly Trials⁠)

Lilly is also studying eloralintide in obesity-related conditions such as:

• obstructive sleep apnoea
• osteoarthritis-related knee pain

as well as combination therapy.

What Is EloraTZP?

EloraTZP combines:

eloralintide + tirzepatide

Tirzepatide already activates:

GIP + GLP-1

Eloralintide adds:

amylin signalling

So the combination targets:

amylin + GIP + GLP-1

Lilly now has Phase 3 AMPLIFY trials planned or enrolling for the co-formulation. One Phase 3 study in people with obesity or overweight and type 2 diabetes plans to enrol approximately 1,000 participants. (Lilly Trials⁠)

So What Is the Main Difference Between the Three?

The simplest distinction is:

Cagrilintide

Long-acting amylin analogue

Strongly associated with CagriSema, combining amylin with semaglutide.

Petrelintide

Long-acting human amylin analogue

Being developed prominently as standalone amylin therapy, while also being combined with a GIP/GLP-1 agonist.

Eloralintide

Selective AMY1 receptor agonist

Aims to refine amylin signalling rather than simply broadly mimicking the hormone.

Which One Is Furthest Ahead?

That depends on what is being measured.

Cagrilintide has the largest late-stage combination evidence base through CagriSema.

Petrelintide has entered its own Phase 3 monotherapy programme.

Eloralintide is also in Phase 3 monotherapy research and is progressing into Phase 3 combination studies with tirzepatide.

So rather than one clearly being “ahead”, they are testing different versions of the amylin strategy.

Which Is the Purest Test of Amylin Alone?

Petrelintide and eloralintide are particularly important here.

Petrelintide asks:

How effective can a long-acting amylin analogue be by itself?

Eloralintide asks:

Can selectively targeting a particular amylin receptor produce an improved profile?

Cagrilintide’s biggest late-stage role has instead been as part of a combination with GLP-1.

Which One Has the Strongest Combination Strategy?

All three are relevant.

Cagrilintide:

cagrilintide + semaglutide

Petrelintide:

petrelintide + CT-388

Eloralintide:

eloralintide + tirzepatide

This gives researchers three slightly different combination philosophies.

Why Is This Competition Scientifically Useful?

Because it may finally tell researchers which part of amylin biology actually matters most.

If several amylin drugs produce similar results despite different receptor profiles, broad amylin signalling may be sufficient.

If selective compounds show meaningfully different tolerability or effectiveness, receptor subtype may be more important than previously realised.

The Phase 3 programmes should provide much better answers.

Which One Is Most Similar to Natural Amylin?

Petrelintide is specifically described as a human amylin analogue.

Cagrilintide is also a long-acting amylin analogue.

Eloralintide takes a more selective receptor-targeting approach.

That does not automatically make one more effective or safer.

It simply reflects different drug-design philosophies.

Could These Drugs Replace GLP-1 Treatments?

Possibly for some people, but that has not been established.

Petrelintide’s development is particularly important because it is testing whether amylin monotherapy could become a meaningful alternative.

However, the combination programmes suggest that pharmaceutical developers also believe amylin may be especially powerful alongside incretin treatment.

The eventual landscape may therefore include both:

amylin-only options

and

amylin + incretin combinations.

Why Might Amylin-Only Therapy Be Attractive?

Possible advantages being investigated include:

• different appetite signalling
• potentially different gastrointestinal tolerability
• an alternative to GLP-1
• different effects on eating behaviour
• different body-composition outcomes

But these remain areas for clinical study rather than established advantages across the class.

What About Lean Mass?

This is becoming one of the biggest questions in the entire field.

Large weight losses inevitably involve some reduction in lean tissue as well as fat.

The CagriSema REDEFINE programme now includes dedicated body-composition studies, including the 104-week REDEFINE 8 trial. (Novo Nordisk⁠)

Petrelintide’s developers have also highlighted body composition as an important area of interest.

The question is no longer simply:

How much weight is lost?

It is increasingly:

How much of that loss comes from fat versus lean tissue?

Could Amylin Become a Maintenance Therapy?

Potentially.

The field is beginning to distinguish between:

active weight-loss treatment

and

long-term weight maintenance.

CagriSema has dedicated maintenance research.

Petrelintide could potentially serve as a foundational amylin therapy, with additional incretin activity added only when greater weight reduction is required. Zealand and Roche explicitly describe this type of strategy in their combination development programme. (Zealand Pharma⁠)

This could represent a major change in how obesity treatment is eventually structured.

How Does This Relate to Cagri + Reta?

Cagrilintide has already been studied preclinically alongside retatrutide.

That research asks whether amylin can add additional biological effects even on top of a powerful:

GIP + GLP-1 + glucagon triple agonist.

Petrelintide and eloralintide could theoretically raise similar questions.

But they are not interchangeable.

A positive cagrilintide-retatrutide study does not automatically establish that petrelintide or eloralintide would behave identically when paired with retatrutide.

Each specific combination requires its own research.

Could One Amylin Drug Eventually Win the Whole Market?

Possibly, but the more likely outcome may be that different compounds serve different roles.

For example:

one might be strongest as monotherapy,

another might work particularly well alongside GLP-1,

and another might offer advantages through receptor selectivity.

We will need Phase 3 and eventually real-world data to know.

The Bigger Question: Analogue or Selective Agonist?

This is probably the most interesting scientific contest.

Cagrilintide and petrelintide broadly follow the strategy:

mimic amylin, but make it longer acting.

Eloralintide follows:

identify a particularly useful amylin receptor and target it more selectively.

If selective receptor agonism performs especially well, future amylin medicines may become progressively more targeted.

If not, broader hormone mimicry may remain the preferred approach.

The Bottom Line

Cagrilintide, petrelintide and eloralintide all target the rapidly emerging amylin pathway, but they do so differently.

Cagrilintide is a long-acting amylin analogue with extensive Phase 3 combination evidence through CagriSema. Novo Nordisk’s programme now includes cardiovascular, body-composition and maintenance trials. (Novo Nordisk⁠)

Petrelintide is a long-acting human amylin analogue that entered a registrational Phase 3 programme in September 2026 after successful Phase 2 development. (Zealand Pharma⁠)

Eloralintide is a selective AMY1 receptor agonist now being tested in Phase 3 both alone and, through EloraTZP, alongside tirzepatide. (Lilly⁠)

Together, these programmes are helping answer a much bigger question:

Should the next generation of metabolic medicines broadly reproduce amylin biology — or selectively engineer the most useful parts of it?

The answer could shape the next wave of peptide therapy well beyond GLP-1.

This article is for research and educational purposes only. Several compounds and combinations discussed remain investigational, and no comparison here establishes one therapy as superior or appropriate for individual use.