Despite recent advances in both diagnosis and prevention, the incidence of
invasive fungal infections continues to rise. Available
antifungal agents to treat
invasive fungal infections include
polyenes,
triazoles, and
echinocandins. Unfortunately, individual agents within each class may be limited by spectrum of activity, resistance, lack of oral formulations, significant adverse event profiles, substantial
drug-drug interactions, and/or variable pharmacokinetic profiles.
Isavuconazole, a second-generation
triazole, was approved by the US Food and Drug Administration in March 2015 and the European Medicines Agency in July 2015 for the treatment of adults with invasive
aspergillosis (IA) or
mucormycosis. Similar to
amphotericin B and
posaconazole,
isavuconazole exhibits a broad spectrum of in vitro activity against yeasts, dimorphic fungi, and molds.
Isavuconazole is available in both oral and intravenous formulations, exhibits a favorable safety profile (notably the absence of QTc prolongation), and reduced
drug-drug interactions (relative to
voriconazole). Phase 3 studies have evaluated the efficacy of
isavuconazole in the management of IA,
mucormycosis, and
invasive candidiasis. Based on the results of these studies,
isavuconazole appears to be a viable treatment option for patients with IA as well as those patients with
mucormycosis who are not able to tolerate or fail
amphotericin B or
posaconazole therapy. In contrast, evidence of
isavuconazole for
invasive candidiasis (relative to comparator agents such as
echinocandins) is not as robust. Therefore,
isavuconazole use for
invasive candidiasis may initially be reserved as a step-down oral option in those patients who cannot receive other
azoles due to tolerability or spectrum of activity limitations. Post-marketing surveillance of
isavuconazole will be important to better understand the safety and efficacy of this agent, as well as to better define the need for
isavuconazole serum concentration monitoring.