Rezafungin exhibits anti-biofilm properties against fungal biofilms in vitro

<b>Objectives</b><br/>We therefore sought to evaluate the comparative activity of rezafungin (RZF) to caspofungin (CAS) and other antifungal classes against biofilms from a large clinical panel of Candida strains (n=167). <br/><br/><b>Methods</b><br/>Biofilm killing and inhibition was assessed using standard XTT metabolic assessment. Biofilm time kill kinetics was also evaluated using metabolic and viable cell counts. Microscopy was performed to visually assess biofilm inhibition. <br/><br/><b>Results</b><br/>Rezafungin was shown to outperform caspofungin and other antifungals against C. albicans, C. parapsiolosis, C. tropicalis, and Nakoseomyces glabratus (previously called C. glabrata) strains with a heterogenous biofilm phenotype. Assessment of high biofilm forming strains at 0.03 µg/mL concentrations showed that rezafungin killed biofilms to an equal or greater extent than caspofungin. Time-kill studies showed a rapid reduction in metabolism and viable colony forming units by both rezafungin and caspofungin, but with little difference between both compounds. Evaluation of biofilm inhibition characteristics of both compounds showed that rezafungin was marginally more effective than caspofungin, which was corroborated by microscopical analyses. <br/><br/><b>Conclusions</b><br/>Together, these data show that rezafungin is non-inferior to caspofungin in terms of anti-biofilm activity and displays characteristics that suggest it can control biofilms more effectively than caspofungin. Further evaluation is required to establish whether these in vitro effects translate clinically, but the data indicates an opportunity for rezafungin to be used for the clinical management of biofilm related diseases.<br/> <br/>