Echinocandin-Related Peptide
A class of lipopeptide antifungal drugs that inhibit beta-1,3-glucan synthase in fungal cell walls. Rezafungin is a peptide-based antifungal in this class approved for invasive candidiasis. Echinocandins represent peptide-based therapeutics targeting fungal rather than bacterial pathogens.
Technical Context
Echinocandins are cyclic hexapeptides with a fatty acid side chain that inhibit beta-1,3-D-glucan synthase — an enzyme essential for fungal cell wall integrity that has no mammalian counterpart (explaining the favourable safety profile). Rezafungin is a novel long-acting echinocandin (half-life ~133 hours) approved for invasive candidiasis, enabling once-weekly IV dosing vs daily dosing for older echinocandins (caspofungin, micafungin, anidulafungin). Rezafungin's structural modification (a choline ether at the C5 ornithine position) increases stability and extends half-life. The echinocandin class illustrates how peptide-based antifungals can target pathogen-specific pathways (beta-1,3-glucan is absent in human cells) to achieve selective toxicity. Resistance through FKS gene mutations (encoding glucan synthase subunits) is clinically significant in Candida species.