Ibrexafungerp, a Novel Triterpenoid Antifungal in Development for the Treatment of Mold Infections

Abstract

Molds are ubiquitous in the environment, and immunocompromised patients are at substantial risk of morbidity and mortality due to their underlying disease and the resistance of pathogenic molds to currently recommended antifungal therapies. This combination of weakened-host defense, with limited antifungal treatment options, and the opportunism of environmental molds renders patients at risk and especially vulnerable to invasive mold infections such as Aspergillus and members of the Order Mucorales. Currently, available antifungal drugs such as azoles and echinocandins, as well as combinations of the same, offer some degree of efficacy in the prevention and treatment of invasive mold infections, but their use is often limited by drug resistance mechanisms, toxicity, drug-drug interactions, and the relative paucity of oral treatment options. Clearly, there is a need for agents that are of a new class that provides adequate tissue penetration, can be administered orally, and have broad-spectrum efficacy against fungal infections, including those caused by invasive mold organisms. Ibrexafungerp, an orally bioavailable glucan synthase inhibitor, is the first in a new class of triterpenoid antifungals and shares a similar target to the well-established echinocandins. Ibrexafungerp has a very favorable pharmacokinetic profile for the treatment of fungal infections with excellent tissue penetration in organs targeted by molds, such as the lungs, liver, and skin. Ibrexafungerp has demonstrated in vitro activity against Aspergillus spp. as well as efficacy in animal models of invasive aspergillosis and mucormycosis. Furthermore, ibrexafungerp is approved for use in the USA for the treatment of women with vulvovaginal candidiasis. Ibrexafungerp is currently being evaluated in clinical trials as monotherapy or in combination with other antifungals for treating invasive fungal infections caused by yeasts and molds. Thus, ibrexafungerp offers promise as a new addition to the clinician's armamentarium against these difficult-to-treat infections.