<qa>  What is an investigational drug being developed as an intravenous treatment for esophAnidulafungin is an investigational drug being developed as an intravenous treatment for esophageal candidiasis, candidemia and other invasive fungal infections. Anidulafungin is an antifungal agent of the echinocandin class, which targets the fungal cell wall of yeast and other filamentous fungi. 