Cyclic Peptides: A Gold Mine Between Small Molecules and Antibodies for Drug Development

Over 40 cyclic peptide drugs are clinically approved, with macrocyclization strategies addressing the stability and cell permeability challenges that limit linear peptides.

Jing, Xiaoshu et al.·Medicinal research reviews·2020·n/a (review)Review
RPEP-04889Reviewn/a (review)2020RETHINKTHC RESEARCH DATABASErethinkthc.com/research

Quick Facts

Study Type
Review
Evidence
n/a (review)
Sample
N=N/A (review)
Participants
N/A (literature review)

What This Study Found

Cyclic peptides offer a middle ground between small molecule drugs and large biologics. Their ring structure gives them better cell permeability and metabolic stability compared to linear peptides, while still allowing them to bind large protein surfaces that small molecules cannot reach.

More than 40 cyclic peptide drugs have reached clinical approval, most derived from natural products. Newer approaches including rational design, mRNA display, phage display, and DNA-encoded libraries are creating cyclic peptides against targets that nature never addressed.

The review covers multiple macrocyclization strategies including disulfide bonds, lactam bridges, hydrocarbon stapling, and click chemistry, each with different trade-offs in terms of stability, permeability, and ease of synthesis.

Key Numbers

40+ clinically approved cyclic peptide drugs; multiple macrocyclization strategies surveyed

How They Did This

This is a comprehensive literature review covering cyclic peptide drug development, including approved drugs, clinical candidates, and discovery platforms. It surveys macrocyclization chemistry, structure-activity relationships, and in vitro evolution methods.

Why This Research Matters

Many important disease targets involve protein-protein interactions that small molecule drugs cannot disrupt. Cyclic peptides can reach these targets while being more stable and cell-permeable than linear peptides.

This review provides a roadmap of current strategies, helping researchers choose the right approach for their specific target.

The Bigger Picture

Many important disease targets are 'undruggable' by small molecules but too expensive to target with antibodies. Cyclic peptides fill this gap, and the field is accelerating with new discovery platforms, improved cyclization chemistry, and better understanding of cell permeability rules.

What This Study Doesn't Tell Us

As a review article, this does not present new experimental data. The strategies described vary widely in their stage of development, from approved drugs to early-stage concepts.

The review may not capture the most recent advances published after its completion.

Questions This Raises

  • ?Which macrocyclization strategy produces the best cell permeability?
  • ?Can cyclic peptides achieve oral bioavailability consistently?
  • ?What are the manufacturing cost advantages over antibodies?

Trust & Context

Key Stat:
40+ approved cyclic peptide drugs already on the market, with the field rapidly expanding through new discovery platforms
Evidence Grade:
Not applicable (comprehensive review). Summarizes clinical data across dozens of approved drugs and ongoing research.
Study Age:
Published in 2020. The cyclic peptide drug pipeline has continued to grow substantially since this review.
Original Title:
A gold mine for drug discovery: Strategies to develop cyclic peptides into therapies.
Published In:
Medicinal research reviews, 40(2), 753-810 (2020)
Database ID:
RPEP-04889

Evidence Hierarchy

Meta-Analysis / Systematic Review
Randomized Controlled Trial
Cohort / Case-Control
Cross-Sectional / ObservationalSnapshot without intervening
This study
Case Report / Animal Study

Summarizes existing research on a topic.

What do these levels mean? →

Frequently Asked Questions

What makes cyclic peptides different from regular drugs?

Cyclic peptides are protein-like molecules bent into a ring shape. This makes them more stable than straight peptides and gives them larger binding surfaces than traditional small-molecule drugs, allowing them to block interactions that other drugs cannot reach.

Are cyclic peptide drugs expensive?

Currently more expensive than small-molecule pills but much cheaper than antibody drugs. Manufacturing costs are decreasing as production technology improves.

Read More on RethinkPeptides

Cite This Study

RPEP-04889·https://rethinkpeptides.com/research/RPEP-04889

APA

Jing, Xiaoshu; Jin, Kang. (2020). A gold mine for drug discovery: Strategies to develop cyclic peptides into therapies.. Medicinal research reviews, 40(2), 753-810. https://doi.org/10.1002/med.21639

MLA

Jing, Xiaoshu, et al. "A gold mine for drug discovery: Strategies to develop cyclic peptides into therapies.." Medicinal research reviews, 2020. https://doi.org/10.1002/med.21639

RethinkPeptides

RethinkPeptides Research Database. "A gold mine for drug discovery: Strategies to develop cyclic..." RPEP-04889. Retrieved from https://rethinkpeptides.com/research/jing-2020-a-gold-mine-for

Access the Original Study

Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.

This study breakdown was produced by the RethinkPeptides research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.