Lilly's Quintuple Agonist (Poster 2839-LB, ADA 2026): Five Receptors, One Molecule
TL;DR: Eli Lilly’s quintuple agonist (GLP-1/GIP/glucagon/amylin/calcitonin) outperformed retatrutide in preclinical rat data; ADA 2026, June 7.
What is the quintuple agonist presented at ADA 2026?
On 7 June 2026, during the ADA 86th Scientific Sessions in New Orleans, researchers from the Indiana Biosciences Research Institute (with research support from Eli Lilly) presented Poster 2839-LB: a long-acting peptide compound designated VRX-0075 that simultaneously activates five metabolic receptors in a single molecule — the GLP-1 receptor, GIP receptor, glucagon receptor, amylin receptor, and calcitonin receptor.[1]
The significance is structural: where retatrutide (LY3437943) — Eli Lilly’s own Phase 3 triple agonist targeting the GLP-1/GIP/glucagon axis — already represents a step beyond the dual-agonist tirzepatide, VRX-0075 adds two further receptor pathways (amylin and calcitonin) to produce what is currently the broadest-spectrum single-peptide metabolic agonist reported in the peer-reviewed conference literature.[2]
In obese rat models, VRX-0075 induced greater body-weight reduction than retatrutide at an equivalent molar dose, with no observable toxicology findings in a non-regulatory setting. Its half-life in rats was approximately 50% longer than semaglutide, a pharmacokinetic profile consistent with once-weekly dosing in humans if clinical development were to proceed.[1]
What are the five receptor targets and what does each one do?
Understanding VRX-0075 requires understanding the function of each receptor pathway it engages. The first three are the same as those targeted by retatrutide; the final two are what make VRX-0075 distinct.
1. GLP-1 Receptor (GLP-1R)
The glucagon-like peptide-1 receptor mediates insulin secretion in a glucose-dependent manner, reduces glucagon secretion, slows gastric emptying, and activates satiety circuits in the hypothalamus. It is the primary target of semaglutide (Ozempic/Wegovy) and the shared anchor of every GLP-1-class agent in clinical development.
2. GIP Receptor (GIPR)
The glucose-dependent insulinotropic polypeptide receptor potentiates post-prandial insulin release and is expressed in adipose tissue, bone, and brain. Dual GIP/GLP-1 agonism (as in tirzepatide) has been shown in Phase 3 to produce greater weight loss than GLP-1 alone, partly attributed to GIPR-mediated effects on energy expenditure and adipocyte biology.
3. Glucagon Receptor (GCGR)
The glucagon receptor drives hepatic glucose output and energy expenditure, particularly in brown adipose tissue. Adding glucagon receptor agonism to GLP-1/GIP is Lilly’s key mechanistic bet with retatrutide — glucagon increases energy expenditure independently of food intake, which may explain the deeper weight loss seen with triple vs dual agonism in Phase 3 comparisons.
4. Amylin Receptor (AmyR)
Amylin is co-secreted with insulin from pancreatic beta cells. It regulates gastric emptying, suppresses post-meal glucagon, and activates satiety centres in the brainstem (area postrema). Amylin receptor agonism appears to produce complementary satiety signalling that is additive to GLP-1-class effects on food intake. Lilly’s separate amylin agonist eloralintide — currently in Phase 2 — demonstrated approximately 20% body-weight reduction as monotherapy and additive effects in combination with tirzepatide in preclinical models at ADA 2026.
5. Calcitonin Receptor (CTR)
The calcitonin receptor is closely related to the amylin receptor — amylin acts through receptor complexes containing the calcitonin receptor core plus receptor activity-modifying proteins (RAMPs). Calcitonin receptor engagement has been implicated in energy balance, bone metabolism, and central satiety effects. VRX-0075 was benchmarked against cagrilintide (an amylin/calcitonin dual agonist in development) for potency at this receptor, and matched it in cell-based assays.[1]
In vitro, VRX-0075 showed potency comparable to retatrutide at the GLP-1, GIP, and glucagon receptors, and potency comparable to cagrilintide (Novo Nordisk’s clinical amylin agonist, part of the CagriSema combination) at the amylin and calcitonin receptors. This dual receptor-class equivalence in a single molecule is the core pharmacological claim of the Poster 2839-LB presentation.[1]
What did Poster 2839-LB report at ADA 2026?
Model: Diet-induced obese rat model. Compound: VRX-0075, a long-acting single-peptide molecule targeting five metabolic receptors. Primary comparison: VRX-0075 vs retatrutide at equivalent molar doses. Key result: VRX-0075 induced greater body-weight reduction than retatrutide with no observable toxicology findings in a non-regulatory setting. Half-life: Approximately 50% longer than semaglutide in the rat model, suggesting compatibility with weekly dosing. In vitro: Potency comparable to retatrutide at GLP-1R/GIPR/GCGR; potency comparable to cagrilintide at AmyR/CTR. Developer: Indiana Biosciences Research Institute (research support: Eli Lilly and Company).
Important note: This is a conference poster presenting preclinical (rodent) data. It has not been peer-reviewed as a full journal article. The results describe pharmacological effects in an animal model only; no human efficacy or safety data exist for VRX-0075. 2839-LB is a conference programme identifier, not a compound name.
Source: ResearchGate abstract: 2839-LB · Indiana Biosciences Research Institute / ADA 2026
The poster sits in the context of Lilly’s broader metabolic pipeline. At the same ADA 2026 meeting, Lilly also presented Poster 3082-LB showing that eloralintide (its selective long-acting amylin receptor agonist, currently in Phase 2 clinical trials) produced additive weight-loss effects when combined with tirzepatide in diet-induced obese rats — complementary evidence that amylin pathway engagement on top of GLP-1-class dual or triple agonism generates measurable preclinical benefit beyond the incretin axis alone.[3]
VRX-0075 can therefore be understood as a single-molecule attempt to combine the triple-G agonism of retatrutide with the amylin and calcitonin receptor engagement that eloralintide achieves as a standalone agent — the difference being that VRX-0075 does this in one peptide rather than two co-administered compounds.
How does the quintuple agonist fit the GLP-1-class agonist progression?
The incremental expansion of receptor targeting in the GLP-1 class is one of the defining themes of metabolic pharmacology research in the 2020s. Each generation has outperformed the previous in head-to-head or phase-matched comparisons.
| Agent | Receptors | Stage (June 2026) | Best weight data (molar dose) | Developer |
|---|---|---|---|---|
| Semaglutide 2.4 mg | GLP-1R | Approved (FDA / MHRA) | −14.9% (68 wks, STEP 1) | Novo Nordisk |
| Tirzepatide 15 mg | GLP-1R + GIPR | Approved (FDA / MHRA) | −20.9% (72 wks, SURMOUNT-1) | Eli Lilly |
| Retatrutide 12 mg | GLP-1R + GIPR + GCGR | Phase 3 / pre-NDA | −28.3% (80 wks, TRIUMPH-1) | Eli Lilly |
| CagriSema (cagrilintide + sema) | GLP-1R + AmyR/CTR | Phase 3 (NDA submitted) | −22.7% (68 wks, REDEFINE 1) | Novo Nordisk |
| VRX-0075 (Poster 2839-LB) | GLP-1R + GIPR + GCGR + AmyR + CTR | Preclinical only | > retatrutide in rats* | Indiana Biosciences / Lilly-funded |
* Preclinical (obese rat) data only; no human data. Cross-trial comparisons are confounded by species, dose, and duration differences. Table for contextual research reference only.
The table illustrates a key principle in receptor pharmacology research: each additional receptor target in the GLP-1 class has, to date, produced superior metabolic effects in matched comparisons. Whether this pattern extends from rodent preclinical models to humans, and at what cost in tolerability, remains to be established for VRX-0075 if it enters clinical development.[2]
Why amylin + calcitonin adds to triple-G agonism
The GLP-1/GIP/glucagon triple-agonist axis (retatrutide) is thought to work through at least three partially independent mechanisms: GLP-1-mediated satiety and insulin potentiation, GIPR-mediated adipose and energy effects, and GCGR-mediated energy expenditure. Adding amylin receptor engagement introduces a fourth pathway — brainstem-mediated satiety signalling that appears to be additive to hypothalamic GLP-1 signalling, acting through distinct neural circuits. The calcitonin receptor, closely coupled to the amylin receptor through RAMP-containing complexes, may extend these effects. At least conceptually, the five pathways of VRX-0075 target satiety signalling from multiple anatomical and molecular angles simultaneously.
What is the development status and when might clinical trials start?
As of June 2026, VRX-0075 is an early-stage preclinical research compound. No Investigational New Drug (IND) application, Phase 1 clinical trial registration, or regulatory pre-submission meeting has been publicly announced. The ADA 2026 poster represents a first public disclosure of the compound in the scientific literature.
It is worth noting that Lilly’s near-term clinical focus remains on retatrutide, for which an NDA (New Drug Application) is targeted Q4 2026 based on the TRIUMPH-1 (obesity) and TRANSCEND-T2D-1 (type 2 diabetes) Phase 3 datasets presented at ADA 2026. The quintuple agonist work represents parallel basic research rather than an imminent pipeline pivot. See the retatrutide FDA approval timeline guide for context on where the Phase 3 compound sits in the regulatory process.
GLP-1-class compounds available for in vitro receptor research
VRX-0075 is not commercially available as a research reagent and is not supplied by Velox Peptides. Researchers studying incretin receptor pharmacology, multi-receptor agonism, or metabolic peptide biology have access to the following HPLC-verified research-grade compounds through Velox Peptides, for use strictly as in vitro research reagents:
Retatrutide and tirzepatide are supplied as research reagents only. They are not medicines and have not been evaluated by the MHRA or FDA for use in our products. Not for human or veterinary use. See our Research Use Policy and MHRA Statement.
For researchers contextualising VRX-0075 within the broader incretin literature, the following guides provide relevant background:
- Retatrutide: triple agonist mechanism of action — how the GLP-1/GIP/glucagon axis is engaged and why three receptors may outperform two
- Is retatrutide a GLP-1 receptor agonist? — receptor class taxonomy and mechanistic distinctions
- Retatrutide vs tirzepatide vs semaglutide — comparison of published Phase 3 data across the three generations of incretin agonism
- Elecoglipron SOLSTICE & VISTA (ADA 2026) — the oral small-molecule GLP-1 RA approach as counterpoint to multi-receptor peptide strategies
References
- Indiana Biosciences Research Institute / Eli Lilly. 2839-LB: A Long-Acting Quintuple Agonist for the GLP-1, GIP, Glucagon, Amylin, and Calcitonin Receptors Induces Greater Weight Loss than Retatrutide in Obese Rats. Poster presented at: ADA 86th Scientific Sessions; 7 June 2026; New Orleans, LA. researchgate.net (abstract)
- Chemical & Engineering News. Not just GLP-1: Peptide-drug conjugate hits 5 obesity targets. C&EN, April 2026. cen.acs.org
- Eli Lilly. The Selective Amylin Analog, Eloralintide, Enhanced Weight-Loss Efficacy When Combined With Tirzepatide in Diet-Induced Obese Rats. Poster 3082-LB, ADA 86th Scientific Sessions, June 2026. lilly.com
- Eli Lilly. Lilly’s triple agonist, retatrutide, drove substantial improvements in weight, A1C, knee osteoarthritis pain, and obstructive sleep apnea. Press release, June 2026. investor.lilly.com
- Eloralintide: Lilly Amylin Drug Hits 20% Weight Loss. The Peptide Catalog, 2026. thepeptidecatalog.com
Frequently Asked Questions
What is the Lilly quintuple agonist presented at ADA 2026?
VRX-0075 is a long-acting quintuple agonist targeting five receptors simultaneously: the GLP-1 receptor, GIP receptor, glucagon receptor, amylin receptor, and calcitonin receptor. Preclinical data were presented as Poster 2839-LB at the American Diabetes Association 86th Scientific Sessions (7 June 2026, New Orleans) by researchers from the Indiana Biosciences Research Institute, with research support from Eli Lilly. As of June 2026, VRX-0075 has not entered human clinical trials and is not an approved compound.
How does VRX-0075 compare to retatrutide?
In obese rat models, VRX-0075 induced greater body-weight reduction than retatrutide at the same molar dose, with no observable toxicology findings in a non-regulatory setting. In cell-based receptor assays, it showed in vitro potency comparable to retatrutide at the GLP-1, GIP, and glucagon receptors, while also matching the potency of cagrilintide at the amylin and calcitonin receptors. These are preclinical results; cross-species translation to humans has not been established. Retatrutide is currently in Phase 3 trials with an NDA targeted Q4 2026.
What are the five receptors targeted by VRX-0075?
The five receptors are: (1) GLP-1 receptor — satiety and insulin potentiation; (2) GIP receptor — post-prandial insulin release and adipose regulation; (3) glucagon receptor — energy expenditure and hepatic glucose output; (4) amylin receptor — gastric emptying, brainstem satiety signalling, glucagon suppression; and (5) calcitonin receptor — closely related to amylin receptor, implicated in energy balance and central satiety. The amylin and calcitonin receptor targets are what distinguish VRX-0075 from retatrutide.
Is VRX-0075 available for research or clinical use?
No. VRX-0075 is a preclinical compound. No clinical trials have been announced. It is not approved by the FDA, MHRA, or any regulatory authority and is not available as a research reagent. Velox Peptides does not supply VRX-0075. Researchers studying GLP-1-class receptor agonism for in vitro work can access retatrutide (GLP-1/GIP/glucagon triple agonist) and tirzepatide (GLP-1/GIP dual agonist) as HPLC-verified research reagents from Velox Peptides for laboratory use only.
How does the quintuple agonist relate to Lilly’s eloralintide programme?
Eli Lilly has a separate clinical amylin programme centred on eloralintide, a selective long-acting amylin receptor agonist in Phase 2 trials. At ADA 2026 (Poster 3082-LB), preclinical data showed eloralintide combined with tirzepatide produced additive weight-loss effects in obese rats. VRX-0075 can be understood as a single-molecule approach combining retatrutide-like triple-G agonism with amylin/calcitonin receptor engagement — packaging in one peptide what the combination of retatrutide plus eloralintide would require two compounds to achieve.