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Study breakdown

How Peptidomimetics Are Making 'Undruggable' Disease Targets Treatable

evidence
The takeaway

Peptidomimetics — molecules that mimic peptide structure but resist degradation — bridge the gap between small-molecule drugs and biologics, enabling therapeutic targeting of previously 'undruggable' protein-protein interactions.

Targeting the 'undruggable'

Peptidomimetics combine peptide-like binding surfaces with drug-like stability, successfully modulating protein-protein interactions that conventional small molecules and biologics cannot reach

What the researchers found

Peptidomimetics — particularly stapled peptides and macrocyclic peptides — have been successfully applied to target numerous 'undruggable' protein-protein interactions, combining the targeting capability of peptides with improved pharmacokinetic properties through conformational constraint.

Why it matters

Most disease-relevant protein-protein interactions cannot be targeted by conventional small-molecule drugs, creating a vast untapped therapeutic space that peptidomimetics can uniquely address.

How the study worked

Narrative review of chemical approaches for creating conformationally constrained peptidomimetics, focusing on stapled peptides and macrocyclization strategies, with examples of successful biological applications.

What this study cannot tell us

As a 2018 review, it may not cover the most recent advances in peptidomimetic chemistry and clinical development. The review focuses on chemical approaches without detailed discussion of manufacturing, cost, or clinical translation challenges.

How to read the evidence

This is a narrative review covering the chemical and biological aspects of peptidomimetic development. It provides a comprehensive overview of the field but does not present new experimental data.

When this study was published

Published in 2018, this review captured the peptidomimetics field during its transition from academic research to clinical development. The field has continued to advance rapidly since publication.

The bigger picture

Peptidomimetics represent the third wave of drug development — after small molecules and biologics. By occupying the middle ground in size and properties, they can reach therapeutic targets inaccessible to either conventional modality. The concept of 'drugging the undruggable' through constrained peptide-like molecules has moved from academic curiosity to clinical reality, with stapled peptides entering clinical trials for cancer and other diseases. This review captures the field at a pivotal transition from proof-of-concept to therapeutic pipeline.

Questions still open

  • Which peptidomimetic platforms are closest to achieving FDA approval for targeting PPIs?
  • Can AI-driven design accelerate the optimization of peptidomimetic drug candidates?
  • How will peptidomimetics compete with or complement antibody-based approaches for PPI modulation?

Common questions

What is a peptidomimetic?
A peptidomimetic is a molecule designed to mimic the shape and function of a natural peptide, but with chemical modifications that make it more drug-like. These modifications can include backbone changes, cyclization (forming rings), or stapling (adding crosslinks) that resist enzymatic degradation, improve cell entry, and extend the molecule's life in the body — addressing the main weaknesses that prevent natural peptides from being good drugs.
Why are protein-protein interactions so hard to target with drugs?
Protein-protein interaction surfaces are typically large (1,500-3,000 square angstroms), relatively flat, and lack the deep pockets that small-molecule drugs need to bind. It's like trying to use a key on a surface that has no keyhole. Peptidomimetics work because they're large enough to cover a significant portion of these flat surfaces while being structured enough to make specific contacts — like a molecular handshake rather than a key-and-lock mechanism.

Read the original research

Peptidomimetics Targeting Protein-Protein Interactions for Therapeutic Development.

Protein and peptide letters, 25(12), 1076-1089

Citation

Zhang, Gan; Andersen, Jessica; Gerona-Navarro, Guillermo. (2018). Peptidomimetics Targeting Protein-Protein Interactions for Therapeutic Development.. Protein and peptide letters, 25(12), 1076-1089. https://doi.org/10.2174/0929866525666181101100842