Enhancing the therapeutic potential of peptide toxins.

INTRODUCTION: Peptide toxins are potent and often exquisitely selective probes of the structure and function of ion channels and receptors, and as such are of significant interest to the pharmaceutical and biotech industries as both therapeutic leads and pharmacological tools. Their progression as clinical candidates, however, faces many of the challenges that are common to peptide drugs generally. Areas covered: The attributes of peptide toxins as therapeutic leads are outlined, as well as some of the limiting factors that have hampered the clinical development of many promising candidates. Strategies to overcome or circumvent these limitations are described, and their applications to peptide toxins from cone snails, sea anemones and scorpions are exemplified. Expert opinion: Peptide toxins have exceeded their promise as valuable pharmacological tools but have yet to yield the anticipated bounty of therapeutic leads. As the number of new peptides identified in venom transcriptomes and proteomes expands rapidly, screening approaches that capture those with genuine therapeutic potential are required, along with methods for enhancing the stability, pharmacokinetics and pharmacodynamics of these peptides.