Highlights
– Weekly subcutaneous eloralintide (an amylin receptor agonist) produced dose‑dependent mean weight loss of 9.4% to 20.9% at 48 weeks versus 0.4% with placebo in a randomized phase 2 trial (n=263).
– Dose‑escalation strategies (eg, 6→9 mg) were associated with large weight loss (≈19.9%) and lower discontinuation due to adverse effects compared with forced higher‑dose starts.
– Secondary benefits included reductions in waist circumference, lipids, hs‑CRP, and small A1c declines in a non‑diabetes population; gastrointestinal adverse events and fatigue were the most common side effects.
Background and Unmet Need
Obesity is a leading global driver of cardiometabolic disease, disability, and health‑care costs. Pharmacotherapy has increasingly become a pillar of management for patients with obesity who do not achieve adequate weight loss with lifestyle measures. Glucagon‑like peptide‑1 (GLP‑1) receptor agonists and the dual GLP‑1/GIP agonist tirzepatide have demonstrated robust weight‑loss efficacy, but gaps remain: not all patients respond or tolerate these agents, and additional mechanisms may provide additive or alternative benefit.
Amylin is a 37‑amino‑acid peptide co‑secreted with insulin by pancreatic beta cells in response to nutrient intake. It slows gastric emptying, suppresses postprandial glucagon secretion, and promotes satiety through central nervous system pathways. Pharmacologic amylin receptor agonism is therefore a plausible strategy to reduce energy intake and body weight; pramlintide, an earlier amylin analog, was used adjunctively in diabetes with modest weight effects. Newer long‑acting amylin agonists are being developed to provide weekly dosing and greater potency, both alone and combined with incretin agonists. Eloralintide is a weekly amylin receptor agonist developed by Eli Lilly that recently completed a phase 2 randomized trial reported at Obesity Week 2025 and published in the Lancet.
Study Design
The trial was a 48‑week, multicenter, double‑blind, randomized, placebo‑controlled phase 2 study conducted at 46 US research centers. The randomized cohort included 263 adults with BMI ≥30 kg/m2 or BMI ≥27 kg/m2 plus at least one weight‑related comorbidity; individuals with diabetes were excluded. Baseline mean age was 49 years, mean BMI was 39.1 kg/m2, and 78% of participants were female.
Participants were randomized to one of seven arms: placebo; eloralintide 1 mg, 3 mg, 6 mg, or 9 mg once weekly for 48 weeks; or two titration strategies that reached higher doses (3→6→9 mg and 6→9 mg escalations). The primary efficacy estimand was mean percent change in body weight from baseline to week 48. Secondary endpoints included categorical weight‑loss thresholds, waist circumference, BMI category shifts, body composition (subset with DEXA), cardiometabolic markers (A1c, lipids, hs‑CRP), and health‑related quality of life (SF‑36v2). Safety was assessed through adverse event reporting, discontinuations, and serious adverse events, with an additional 10‑week safety follow‑up after treatment ended.
Key Results
Primary efficacy: weight loss
At week 48 the mean percent body‑weight reduction (efficacy estimand) was greater with all eloralintide doses versus placebo (placebo −0.4%). Observed mean percent weight reductions ranged from 9.4% with 1 mg to 20.9% with the 9 mg dose. The two dose‑escalation arms achieved substantial losses: 19.9% for the 6→9 mg group and 16.4% for the 3→9 mg group. These results indicate a clear dose‑response and demonstrate that titration to higher target doses can yield large, clinically meaningful weight loss.
Categorical outcomes and body composition
Weight‑loss thresholds were notable: in the 6→9 mg titration group, 92% of participants achieved ≥10% weight loss; the 9 mg fixed‑dose group achieved ≥10% in 81% of participants. Reductions in waist circumference reached as much as 17.1 cm (~6–7 inches) in the 6→9 mg escalation group. BMI reductions paralleled percent weight loss (range 3.7 to 7.8 BMI units across doses versus 0.2 with placebo). In the three groups receiving 9 mg at any point, 78%–80% of participants shifted to a lower clinically defined BMI category, compared with 21% with placebo.
Among a DEXA‑scanned subset, the majority of weight loss was attributable to fat mass rather than lean mass — an important consideration for functional outcomes and metabolic health.
Cardiometabolic and patient‑reported outcomes
Eloralintide produced modest improvements in glycemic markers (A1c decreased by up to 0.38 percentage points in the 6 mg group versus −0.13 in placebo). Lipid profiles improved across doses — reductions in total cholesterol, LDL cholesterol, and non‑HDL cholesterol were greater than with placebo, and HDL increased with eloralintide. High‑sensitivity C‑reactive protein (hs‑CRP) was reduced by up to 64% from elevated baseline levels, consistent with anti‑inflammatory effects accompanying weight reduction. Most treatment groups (except 1 mg) showed improvements in physical functioning on SF‑36v2 at 48 weeks.
Safety and tolerability
Overall, 81% of participants on eloralintide reported ≥1 adverse event versus 71% on placebo; serious adverse event rates were similar (5% vs 6%). Adverse events leading to treatment discontinuation occurred in 10% of eloralintide recipients overall (notably 21% in the 6 mg fixed‑dosing arm) versus 8% with placebo. Gastrointestinal adverse events were the most commonly reported: nausea occurred in 32.7% of eloralintide participants (13.5% placebo), vomiting in 8.2% (none in placebo), and constipation and diarrhea in approximately 15% each (placebo rates 5.8% and 9.6%, respectively). Fatigue was reported more frequently with eloralintide (26.9%) than placebo (11.5%), and was highest in the 6→9 mg group (45.8%).
Importantly, arms that used stepwise dose escalation (eg, 3→9 mg and 6→9 mg) showed lower rates of nausea and discontinuation compared with the fixed 6 mg start, indicating that gradual up‑titration improves tolerability without compromising efficacy. Most adverse events were mild to moderate; there were no deaths reported in the trial.
Expert Commentary and Context
Eloralintide’s magnitude of weight loss — up to ~21% at the highest dose — places amylin agonism in the higher echelon of pharmacologic obesity therapies, comparable in some arms to results reported for GLP‑1 and dual agonists in late‑phase trials. The physiologic rationale is compelling: amylin regulates satiety and gastric emptying via distinct receptors and central circuits, potentially offering complementary mechanisms to GLP‑1 receptor agonists. The development of long‑acting weekly amylin agonists may therefore expand therapeutic options, either as monotherapy for patients who cannot tolerate GLP‑1 agents or as combination therapy to enhance efficacy and mitigate adverse effects.
However, several caveats should guide interpretation. This was a phase 2 trial with a relatively small sample (n=263), a high proportion of female participants (78%), and exclusion of patients with diabetes — limiting generalizability. Longer‑term durability of weight loss beyond 48 weeks, cardiovascular safety, and effects in diverse clinical populations remain unknown. Head‑to‑head comparisons vs established agents and combination trials (eg, amylin + GLP‑1) will be required to define optimal use cases. The tolerability profile, dominated by GI symptoms and fatigue, resembles that of other centrally active appetite‑suppressing agents; the data here indicate that titration strategies mitigate these events and improve adherence.
From a mechanistic and translational perspective, the preferential loss of fat mass and favorable changes in waist circumference and inflammatory markers are clinically meaningful and suggest potential downstream benefits for metabolic risk; however, whether these translate to improved cardiovascular outcomes will require targeted outcome trials.
Limitations
Key limitations include the phase 2 design and sample size, demographic skew toward women, exclusion of patients with diabetes, short post‑treatment follow‑up for assessing weight regain, and lack of cardiovascular outcomes or formal comparisons against existing standard agents. The published report (Lancet / Obesity Week 2025) did not provide long‑term safety or pregnancy data. Finally, details on the trial registry number and the full dataset for subgroup and per‑protocol analyses were not provided in the conference release.
Clinical Implications and Next Steps
Eloralintide adds an amylin‑based mechanism to the pharmacologic armamentarium for obesity and may be particularly useful for patients who do not respond to or tolerate GLP‑1 receptor agonists, or as part of combination regimens to exploit complementary mechanisms. Clinicians should remain attentive to gastrointestinal adverse effects and consider structured titration to improve tolerability. Pending phase 3 data, longer‑term safety information, and comparisons with current standards of care, eloralintide should be considered an investigational option with promising efficacy but unresolved long‑term benefit‑risk balance.
Future research priorities include: larger, more diverse phase 3 trials; head‑to‑head and combination trials with GLP‑1/GIP agonists; dedicated cardiovascular and renal outcome studies; real‑world tolerability and adherence assessments; and mechanistic studies to define central vs peripheral effects and the relative contribution of reduced intake versus altered energy expenditure.
Funding and ClinicalTrials.gov
The trial was conducted by investigators reporting support from Eli Lilly, the developer of eloralintide. The investigators presented results at The Obesity Society’s Obesity Week 2025 and reported simultaneous publication in the Lancet. A clinicaltrials.gov registration number was not specified in the conference materials referenced here; readers should consult the published Lancet report and the trial registry for protocol and registration details when available.
Conclusion
Weekly eloralintide produced large, dose‑dependent weight loss over 48 weeks in a phase 2 randomized trial, with meaningful improvements in waist circumference, body composition, lipids, and inflammatory markers. Tolerability was acceptable overall and improved with stepwise dose escalation. These results support further development in phase 3 programs and raise the possibility that amylin receptor agonists could become an important addition to obesity pharmacotherapy, pending confirmation of long‑term safety, durability, and comparative effectiveness.
References and Further Reading
– Investigator presentation at The Obesity Society, Obesity Week 2025 (Eloralintide phase 2 results) and simultaneous publication in the Lancet (2025). Please refer to the published Lancet article for full trial details and citation.
– Review articles on amylin physiology and pharmacology, clinical practice guidelines on medical management of obesity, and recent trials of GLP‑1 and dual agonists provide broader context for the potential role of amylin receptor agonists in obesity care.
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A clinical office scene in soft clinical lighting: a diverse group of middle‑aged adults (predominantly women) in casual activewear look at a tablet held by a clinician that displays a clear descending weight curve and body silhouette icons; a scale and measuring tape visible in the background; color palette cool blues and whites; photographic realism, shallow depth of field emphasizing the tablet screen.
