rezafungin rezafungin rezafungin (trade name rezzayo) is an antifungal drug of the echinocandin class. rezafunginclinical datatrade namesrezzayoother namesbiafungin; cd101license data us dailymed: rezafungin identifierscas number1396640-59-7pubchem cid78318119drugbank16310uniig013b5478jkeggd11197chemical and physical dataformulac63h85n8o17+molar mass1226.4 g/mol rezafungin was approved by the food and drug administration in march 2023 for the treatment of candidemia and invasive candidiasis in adults with limited or no alternative treatment options.