Eloralintide

What is Eloralintide?#

Eloralintide (LY3841136) is a selective, long-acting amylin receptor agonist developed by Eli Lilly and Company for the treatment of obesity. It is a modified analog of human amylin -- a 37-amino acid peptide hormone co-secreted with insulin from pancreatic beta cells -- conjugated to a C20 fatty diacid that enables once-weekly subcutaneous administration.

What distinguishes eloralintide from earlier amylin-based therapies is its selectivity. While pramlintide (the only approved amylin analog) and cagrilintide (Novo Nordisk) activate both amylin and calcitonin receptors non-selectively, eloralintide was engineered to preferentially activate the AMY1 receptor with 12-fold selectivity over the calcitonin receptor. This selectivity profile may account for the favorable gastrointestinal tolerability observed in clinical trials, as calcitonin receptor activation is associated with nausea.

In a 48-week phase 2 trial published in The Lancet (Billings et al., 2025), eloralintide produced dose-dependent weight reductions of 9.5% to 20.1% in adults with obesity or overweight, with the highest doses approaching the efficacy of leading GLP-1 receptor agonists through a completely distinct mechanism.

Mechanism of Action#

Amylin is a neuroendocrine hormone that acts primarily through receptors in the area postrema and hypothalamus to regulate energy homeostasis. Amylin receptors are heterodimeric complexes composed of the calcitonin receptor (CTR) core paired with receptor activity-modifying proteins (RAMPs), generating three receptor subtypes: AMY1R (CTR+RAMP1), AMY2R (CTR+RAMP2), and AMY3R (CTR+RAMP3).

Eloralintide's mechanism involves several coordinated pathways:

• Satiety signaling: Activates amylin receptors in the area postrema, a circumventricular organ that senses circulating hormones and relays satiety signals to the nucleus of the solitary tract and hypothalamus
• Food intake reduction: Reduces meal size through promotion of meal-ending satiation, leading to decreased caloric intake
• Hypothalamic regulation: Indirectly activates hypothalamic histamine H1 receptors in the ventromedial hypothalamus, contributing to appetite suppression
• Energy expenditure: Preclinical evidence suggests amylin receptor activation increases energy expenditure through central mechanisms
• Receptor selectivity: 12-fold selectivity for AMY1R over CTR and 11-fold over AMY3R, potentially reducing calcitonin receptor-mediated nausea
• Body composition: Preclinical data show preferential fat mass loss with reduced loss of lean mass compared with non-selective amylin analogs

The amylin pathway is mechanistically independent of the GLP-1 and GIP pathways exploited by semaglutide and tirzepatide, making eloralintide a candidate for combination therapy to achieve additive or synergistic weight loss.

Clinical Development#

Eloralintide has progressed through a structured clinical development program:

• Phase 1 (Proof of Concept): Two Phase 1 studies in healthy volunteers and participants with obesity demonstrated dose-proportional pharmacokinetics, weight loss of 2.6-11.3% at 12 weeks, and favorable GI tolerability (PMID: 41559929, 41109426)
• Phase 2 (Lancet 2025): 48-week, 263-patient trial demonstrated dose-dependent weight loss of 9.5-20.1% vs 0.4% placebo across six dose arms (PMID: 41207310)
• Phase 3 (ENLIGHTEN Program): Multiple Phase 3 trials initiated, including ENLIGHTEN-4 (NCT07282600) evaluating eloralintide in adults with obesity/overweight and knee osteoarthritis. Additional Phase 3 trials for obesity monotherapy enrolling in 2026
• Combination studies: Phase 2 trial evaluating eloralintide in combination with tirzepatide is ongoing

Important Considerations#

Eloralintide is an investigational medication not yet approved by any regulatory authority. Key considerations include:

• All efficacy data are from Phase 1 and Phase 2 trials; Phase 3 confirmatory results are pending
• The Phase 2 trial excluded patients with type 2 diabetes, so efficacy in this population is not yet established
• Nausea and fatigue are dose-dependent and more common at higher doses, though slower titration reduces their incidence
• The 48-week Phase 2 trial may not reflect long-term weight maintenance outcomes
• Eloralintide does not address the broader metabolic dysfunction targeted by incretin-based therapies (e.g., glucose-dependent insulin secretion)

Key Research Findings#

Eloralintide Phase 2 Trial (Lancet), published in Lancet (Billings LK et al., 2025; PMID: 41207310):

• Mean weight loss ranged from 9.5% (1 mg) to 20.1% (9 mg) compared with 0.4% for placebo at 48 weeks
• All six active treatment arms met the primary endpoint of superior weight reduction versus placebo
• Improvements observed in waist circumference, blood pressure, lipid profiles, glycemic control, and inflammatory markers
• Nausea was the most common adverse event (11-64% depending on dose), with fatigue as the second most common

Eloralintide Discovery to Clinical Proof of Concept, published in Molecular Metabolism (Briere DA et al., 2025; PMID: 41109426):

• Demonstrated 12-fold selectivity for AMY1R over calcitonin receptor
• Preclinical comparison showed less nausea (conditioned taste avoidance) and better quality of weight loss (preferential fat loss) than cagrilintide

Related Reading#

• Eloralintide research studies and evidence
• Eloralintide dosing protocols
• Eloralintide side effects profile
• Cagrilintide research guide
• Tirzepatide research guide
• Semaglutide research guide