The
triazole class of antifungal drugs comprises first-line agents for the treatment of several invasive
fungal diseases.
Isavuconazole is a novel broad-spectrum
triazole agent. Here we summarize its characteristics and compare it with the currently available
antifungal agents.
Isavuconazole is administered as a
prodrug, and it is water soluble. Oral and intravenous formulations are available. Its intravenous formulation does not contain
cyclodextrin, which is an advantage over
voriconazole, considering the potential for nephrotoxicity of
cyclodextrin. As with other
azoles,
isavuconazole requires a loading dose. Due to its prolonged half-life, a once-a-day regimen is possible. Considering that
isavuconazole shares the same mechanism of action with the other
triazoles, cross-resistance is an important concern in the class. Tolerability and safety profiles are favorable, and no serious adverse events have been consistently reported. Significant interactions with drugs metabolized by
cytochrome P450 are expected to occur, especially with substrates and inducers of the
CYP3A4 enzyme.
Isavuconazole has in vitro activity against most medically important fungi, including species of Candida, Aspergillus, and Cryptococcus. It has some activity against the agents of
mucormycosis. Clinical data regarding
isavuconazole remain limited because ongoing trials have not yet been completed or published.
Isavuconazole has the potential to become first-line
therapy for invasive
aspergillosis. It also has the potential for use in the context of antifungal prophylaxis,
salvage therapy, or in combination regimens. Results of clinical trials are ultimately expected in order to adequately position
isavuconazole in the current antifungal armamentarium.