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Study breakdown

Peptibodies: Combining the Best of Peptides and Antibodies Into One Drug

evidence
The takeaway

Peptibodies fuse bioactive peptides with antibody Fc domains, overcoming peptides' stability and clearance problems while retaining their tissue penetration and target specificity.

2 approved peptibodies

Romiplostim and dulaglutide demonstrate the clinical viability of fusing peptides to antibody Fc domains, with dulaglutide becoming one of the best-selling diabetes drugs worldwide.

What the researchers found

Peptibodies (peptide-Fc fusions) overcome key limitations of therapeutic peptides — including low stability, rapid clearance, and poor absorption — by fusing bioactive peptides to the Fc domain of immunoglobulin. This fusion enhances half-life, stability against proteolytic digestion, and overall efficacy while retaining the peptide's advantages of tissue penetration, cellular internalization, and low immunogenicity. Two peptibodies have achieved regulatory approval: romiplostim (EMA/FDA, for thrombocytopenia) and dulaglutide (FDA, a GLP-1 receptor agonist for type 2 diabetes).

Why it matters

Peptides represent an enormous therapeutic opportunity — they can target pathways that small molecules and antibodies cannot. But their short half-lives and instability have limited clinical success. Peptibodies solve this problem elegantly, and their success (particularly dulaglutide/Trulicity, one of the best-selling diabetes drugs) demonstrates the commercial and clinical viability of this approach. As more peptide targets are discovered, the peptibody platform could enable rapid translation to the clinic.

How the study worked

Narrative review covering the intrinsic properties of therapeutic peptides, the technology and production process for peptibodies, and their therapeutic applications across multiple disease areas.

What this study cannot tell us

As a narrative review, this paper does not present original data. The review primarily focuses on approved peptibodies and those in development, but does not provide a systematic assessment of failure rates or challenges encountered in peptibody development. Manufacturing complexity and cost of Fc fusion proteins compared to simple peptides are acknowledged but not deeply explored.

How to read the evidence

This is a narrative review providing an overview of peptibody technology, production, and applications. It synthesizes existing literature rather than presenting new clinical or experimental data.

When this study was published

Published in 2024, this review captures the current state of peptibody technology during a period of rapid growth in peptide-based therapeutics.

The bigger picture

Peptibodies sit at the convergence of two of the largest drug modality classes — peptides and antibodies. As the peptide drug market grows (projected to exceed $50 billion), engineering platforms like peptibodies that solve peptides' inherent pharmacokinetic limitations become increasingly important. The success of dulaglutide demonstrates that peptibodies can become blockbuster drugs, and the platform is likely to yield more approved therapies in the coming years.

Questions still open

  • What peptide-Fc fusion candidates are closest to FDA approval beyond romiplostim and dulaglutide?
  • How does the cost of manufacturing peptibodies compare to producing the peptide and antibody separately?
  • Could peptibody technology be applied to enhance the stability of emerging therapeutic peptides like BPC-157 or thymosin alpha-1?

Common questions

What is a peptibody and how does it work?
A peptibody is a hybrid drug made by attaching a therapeutic peptide to the Fc region of an antibody (the 'tail' portion). The peptide provides the targeted biological activity, while the Fc domain dramatically extends the drug's time in the body by preventing rapid breakdown and clearance. This means less frequent dosing and more consistent drug levels.
What approved drugs are peptibodies?
Two peptibodies are currently approved: romiplostim (Nplate), used to treat low platelet counts, and dulaglutide (Trulicity), a GLP-1 receptor agonist for type 2 diabetes. Dulaglutide in particular has been enormously successful, becoming one of the top-selling diabetes drugs globally thanks to its once-weekly dosing enabled by the Fc fusion technology.

Read the original research

Peptibodies: Bridging the gap between peptides and antibodies.

International journal of biological macromolecules, 278(Pt 2), 134718

Citation

Khezri, Hamidhossein; Mostafavi, Mahdiyeh; Dabirmanesh, Bahareh; Khajeh, Khosro. (2024). Peptibodies: Bridging the gap between peptides and antibodies.. International journal of biological macromolecules, 278(Pt 2), 134718. https://doi.org/10.1016/j.ijbiomac.2024.134718