Isavuconazole

Warning

H302 (33.3%): Harmful if swallowed [Warning Acute toxicity, oral]

P203, P261, P264, P264+P265, P270, P271, P280, P301+P317, P302+P352, P304+P340, P305+P351+P338, P317, P318, P321, P330, P332+P317, P337+P317, P362+P364, P405, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 3 reports by companies from 3 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

J02AC05

J - Antiinfectives for systemic use

QJ - Antiinfectives for systemic use

Isavucoanzole exhibits antifungal activity against most strains of _Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger_, and Mucorales such as _Rhizopus oryzae_ and Mucormycetes species _in vivo_ and _in vitro_. In a cardiac electrophysiology study involving healthy subjects, isavuconazole induced dose-related shortening of the QTc interval but the additive effect of isavuconazole with other QTc-prolonging drug is unknown.

Isavuconazole displays fungicidal actions by disrupting the biosynthesis of ergosterol, which is a key component of fungal cell membrane. It inhibits cytochrome P-450 dependent enzyme lanosterol 14-alpha-demethylase that mediates the conversion of lanosterol to ergosterol. The side arm of of the active isavuconazole molecule allows for greater affinity for the binding pocket in the fungal CYP51 protein by orienting the triazole ring of the molecule to engage with the heme moiety at the bottom of the binding pocket. This explains the wide antifungal spectrum of isavuconazole and possible cross-resistance to other triazoles. As a result of lanosterol 14-alpha-demethylase inhibition, toxic methylated sterol precursors such as 14-α-methylated lanosterol, 4,14-dimethylzymosterol, and 24-methylenedihydrolanosterol alter the function of fungal membrane and accumulate within the fungal cytoplasm. Depletion of ergosterol within the fungal cell membrane leads to decreased structural integrity and function of the cell membrane, inhibited fungal cell growth and replication, and ultimately cell death. Mammalian cell demethylation is less sensitive to isavuconazole inhibition. Mechanism of resistance and reduced susceptibility to isavuconazole arises from mutations in the fungal cyp51A and cyp51B genes coding for the target protein lanosterol 14-alpha-demethylase. Other multiple mechanisms leading to resistance, including changes in sterol profile and elevated efflux pump activity of fungal species, cannot be excluded.