Enfumafungin Derivative MK-3118 Shows Increased In Vitro Potency against Clinical Echinocandin-Resistant Candida Species and Aspergillus Species Isolates

ABSTRACT MK-3118 is as an orally active new antifungal in the early stage of clinical development that inhibits the biosynthesis of β-(1,3)-glucan. We evaluated the in vitro activity of this compound against wild-type and echinocandin-resistant (ER) isolates containing mutations in the FKS gene(s) of Candida spp. and Aspergillus spp. MK-3118 demonstrated enhanced efficacy for most C. albicans and C. glabrata ER isolates relative to caspofungin, with decreased MICs and half-maximal inhibitory concentrations (IC 50 s).