Efpeglenatide: long-acting GLP-1 receptor agonist research overview

Efpeglenatide is a long-acting, once-weekly GLP-1 receptor agonist originally developed by Hanmi Pharmaceutical of South Korea. It is notable in the GLP-1 pharmacology landscape for two reasons: its participation in the AMPLITUDE-O cardiovascular outcomes trial — which demonstrated significant reduction in major adverse cardiovascular events in adults with type 2 diabetes at high cardiovascular risk — and its complex development history, which saw rights licensed to Sanofi in 2015 and returned to Hanmi in 2020. As of 2026, efpeglenatide remains under active development by Hanmi, with phase 3 obesity trials completed or ongoing and Korean regulatory filings in progress. It is not approved by the FDA or EMA.

What is efpeglenatide?

Efpeglenatide (INN; development code HM11260C) is a synthetic GLP-1 receptor agonist peptide based on the exendin-4 scaffold — the same peptide backbone underlying exenatide — conjugated to an IgG4-Fc fragment via a linker to extend its plasma half-life and enable once-weekly subcutaneous dosing. The exendin-4 sequence is a 39-amino acid peptide originally isolated from the venom of the Gila monster (Heloderma suspectum); it shares approximately 50% sequence homology with native human GLP-1 and is a full agonist at the GLP-1 receptor but is not subject to DPP-4 cleavage at the same rate as native GLP-1. The IgG4-Fc fusion extends efpeglenatide's half-life to approximately 6–7 days, allowing once-weekly administration.

Hanmi Pharmaceutical initially licensed efpeglenatide to Sanofi in 2015, and Sanofi conducted the AMPLITUDE-O cardiovascular outcomes trial. In 2020, Sanofi returned the rights to Hanmi, citing strategic realignment. The molecule returned to Hanmi's pipeline, where it has since been pursued in obesity indications in addition to type 2 diabetes. Phase 3 obesity trials have been conducted in South Korea, and Hanmi filed for Korean regulatory approval in late 2025. A US FDA approval pathway is not confirmed as of May 2026; Hanmi has expressed interest in a US filing, pending further development milestones.

Mechanism of action

Efpeglenatide is a GLP-1 receptor (GLP-1R) full agonist. Upon binding GLP-1R — a class B G protein-coupled receptor — efpeglenatide activates adenylate cyclase, elevates intracellular cAMP in pancreatic beta cells, and stimulates glucose-dependent insulin secretion while suppressing glucagon in hyperglycemic conditions. Central GLP-1R activation in the hypothalamus and nucleus tractus solitarius suppresses appetite and reduces caloric intake. Efpeglenatide also slows gastric emptying, which reduces postprandial glucose excursions and contributes to early satiety.

The exendin-4 backbone confers DPP-4 resistance superior to that of native GLP-1 analogs at the N-terminus (native GLP-1 is rapidly cleaved at position 2 by DPP-4; exendin-4 has a distinct N-terminal sequence that reduces this cleavage). The IgG4-Fc fusion further extends circulating half-life through FcRn-mediated recycling, analogous to the mechanism used by IgG antibodies. This dual protection against rapid clearance enables the once-weekly dosing schedule observed in AMPLITUDE-O and the obesity phase 3 program.

What the research shows

The pivotal AMPLITUDE-O trial (A Phase 3 Study of Efpeglenatide in Adults with Obesity and/or Type 2 Diabetes) was a multicenter, randomized, double-blind, placebo-controlled cardiovascular outcomes trial (CVOT) enrolling 4,076 adults with type 2 diabetes who had either a history of cardiovascular disease or chronic kidney disease plus at least one additional cardiovascular risk factor. Participants were randomized 1:1:1 to efpeglenatide 4 mg weekly, efpeglenatide 6 mg weekly, or placebo, in addition to standard of care. The trial was published by Gerstein et al. in the New England Journal of Medicine in 2021 (PMID 34010525).

The primary endpoint — a composite of major adverse cardiovascular events (MACE: cardiovascular death, non-fatal myocardial infarction, non-fatal stroke) — occurred in 7.0% of the efpeglenatide group versus 9.2% of the placebo group over a median follow-up of 1.81 years (hazard ratio 0.73; 95% CI 0.58–0.92; P<0.001 for non-inferiority; P=0.007 for superiority) [1]. This demonstrated both cardiovascular safety and a significant cardiovascular benefit, making efpeglenatide one of the GLP-1 agonists with a positive CVOT at the time of publication.

A secondary composite renal outcome (decline in eGFR or macroalbuminuria) occurred in 13.0% of the efpeglenatide group versus 18.4% of placebo (HR 0.68; 95% CI 0.57–0.79; P<0.001) [1]. A post-hoc dose-response analysis published in Circulation in 2023 (PMID 36802715) explored the cardiovascular effect across the 4 mg and 6 mg doses and found consistent benefit at both. These cardiorenal findings mirror outcomes seen with other approved GLP-1 agonists in CVOT settings (LEADER for liraglutide, SUSTAIN-6 for semaglutide) and are consistent with a class effect.

In the obesity development program, Hanmi's phase 3 trial in Korean adults with obesity demonstrated meaningful body weight reductions. At 40 weeks of an ongoing 64-week trial, 79.4% of participants achieved ≥5% weight loss, 49.5% achieved ≥10%, and 19.9% achieved ≥15%. A 30% weight reduction was reported in a subset of participants at the highest doses in some analyses. These results formed the basis for Hanmi's Korean regulatory submission in late 2025 and the launch of a commercialization task force in April 2026.

Pharmacokinetics

Efpeglenatide is administered subcutaneously once weekly. Its plasma half-life is approximately 6–7 days, enabled by the IgG4-Fc fusion — the Fc fragment engages neonatal Fc receptor (FcRn)-mediated recycling, preventing lysosomal degradation and re-releasing the compound into circulation. This pharmacokinetic mechanism differs from the fatty-acid acylation used by semaglutide and liraglutide (which extend half-life through albumin binding). Steady-state plasma concentrations are typically achieved after 4–5 weeks of weekly dosing. In AMPLITUDE-O, the doses of 4 mg and 6 mg weekly were the evaluated clinical doses.

Because efpeglenatide is a peptide conjugate (not a small molecule), it is not metabolized by CYP450 enzymes. Clearance occurs primarily via proteolytic degradation of the peptide component and FcRn-cycling turnover. Renal impairment has less effect on efpeglenatide clearance than on shorter-acting GLP-1 agonists like exenatide, given the dominant role of non-renal clearance pathways. Full pharmacokinetic parameters are described in the AMPLITUDE-O design paper (Gerstein et al., design paper, PubMed PMID 33026143) and associated clinical pharmacology documents from the Sanofi development period.

Common research dose ranges

Not medical advice. These are ranges reported in research literature, not personalized recommendations. Consult your physician.

In AMPLITUDE-O, the evaluated weekly subcutaneous doses were 4 mg and 6 mg. In the obesity phase 3 program conducted in South Korea, higher doses were investigated consistent with the greater dose requirements seen in obesity trials across the GLP-1 class. Efpeglenatide is not FDA-approved and has no US approved prescribing information. All dose ranges cited here derive solely from published investigational trial protocols and should not be interpreted as clinical guidance. Researchers should consult primary trial publications and ClinicalTrials.gov registry entries for the relevant protocol doses.

Storage and handling

Efpeglenatide is an Fc-fusion peptide administered via subcutaneous injection. Like other injectable GLP-1 agonist peptides, it requires refrigerated storage at 2–8 °C and should be protected from freezing and light. Once in use, specific in-use stability conditions would be defined in the approved labeling upon regulatory approval. Research-grade material should be handled per the supplier's certificate of analysis, with lyophilized powder stored at −20 °C and reconstituted solutions stored at 2–8 °C; single freeze-thaw cycles should be minimized to preserve bioactivity.

What efpeglenatide is NOT

Efpeglenatide is not exenatide. While both are based on the exendin-4 peptide scaffold, exenatide (Byetta, Bydureon) is a direct analog of exendin-4 without the IgG4-Fc fusion; Byetta requires twice-daily injection and Bydureon is a once-weekly microsphere formulation. Efpeglenatide's Fc-fusion is a distinct molecular engineering approach that changes its pharmacokinetics, immunogenicity profile, and molecular weight substantially. Efpeglenatide is not dulaglutide, which is a different GLP-1 peptide (GLP-1 analog, not exendin-4 based) fused to an IgG4-Fc by a different linker design (see the published dulaglutide guide on this platform). Efpeglenatide is not semaglutide or liraglutide; these agents use fatty-acid acylation rather than Fc-fusion for half-life extension and employ GLP-1 analog sequences rather than the exendin-4 backbone.

The rights history of efpeglenatide is sometimes misrepresented. Sanofi did not develop efpeglenatide independently — it licensed the compound from Hanmi, conducted AMPLITUDE-O, and returned rights to Hanmi in 2020. Hanmi is the original developer and current holder of all rights to efpeglenatide. There is no Sanofi commercialization pathway for this compound.

Frequently asked questions

Is efpeglenatide FDA-approved?

No. As of May 2026, efpeglenatide is not approved by the FDA or EMA. It is under development by Hanmi Pharmaceutical with Korean regulatory filings initiated in late 2025. US approval is not confirmed.

What did AMPLITUDE-O prove?

AMPLITUDE-O demonstrated that efpeglenatide significantly reduced the risk of major adverse cardiovascular events (MACE) compared to placebo in adults with type 2 diabetes at high cardiovascular risk (HR 0.73; P=0.007 for superiority). It also showed significant renal protection. This was a superiority finding, not just non-inferiority [PMID 34010525].

Why did Sanofi return rights to Hanmi?

Sanofi cited changes in its business strategy and portfolio prioritization when it returned efpeglenatide rights to Hanmi in 2020 — before AMPLITUDE-O's results were published. The return was a strategic decision, not a reflection of the drug's efficacy or safety profile.

How does efpeglenatide differ structurally from dulaglutide?

Both efpeglenatide and dulaglutide use IgG4-Fc fusion for half-life extension. However, efpeglenatide uses an exendin-4 peptide backbone (50% GLP-1 sequence homology), while dulaglutide uses a modified GLP-1 analog backbone (>90% GLP-1 sequence homology). This results in different receptor binding kinetics and immunogenicity profiles.

Is efpeglenatide available for research use?

Efpeglenatide is not commercially available for clinical use in the US or EU as of May 2026. Research-grade material may be available from specialized peptide synthesis vendors as an investigational compound. All research use outside approved clinical trials requires appropriate regulatory and institutional oversight.

References

1. Gerstein HC, et al. Cardiovascular and Renal Outcomes with Efpeglenatide in Type 2 Diabetes. N Engl J Med. 2021;385(10):896–907. PMID 34010525. https://pubmed.ncbi.nlm.nih.gov/34010525/

2. Gerstein HC, et al. Design and baseline characteristics of the AMPLITUDE-O cardiovascular outcomes trial of efpeglenatide. PubMed PMID 33026143. https://pubmed.ncbi.nlm.nih.gov/33026143/

3. Lam CSP, et al. Exploring the Relationship Between Efpeglenatide Dose and Cardiovascular Outcomes in Type 2 Diabetes: Insights from the AMPLITUDE-O Trial. Circulation. 2023. PMID 36802715. https://pubmed.ncbi.nlm.nih.gov/36802715/

4. Gerstein HC, et al. Efpeglenatide and Clinical Outcomes With and Without Concomitant SGLT-2 Inhibition in Type 2 Diabetes: Exploratory Analysis of AMPLITUDE-O. PMID 34775781. https://pubmed.ncbi.nlm.nih.gov/34775781/

5. Hanmi Pharmaceutical: Phase 3 clinical trial results of efpeglenatide in obesity. Korea Herald, 2024. https://m.koreaherald.com/article/2642578