Examining the Benefits of the Boron-Based Mechanism of Action and Physicochemical Properties of Tavaborole in the Treatment of Onychomycosis.

Onychomycosis is a fungal infection of the nail primarily caused by the dermatophytes Trichophyton rubrum and Trichophyton mentagrophytes. The topical-based treatment of onychomycosis remains a challenge because of the difficulty associated with penetrating the dense, protective structure of the keratinized nail plate. Tavaborole is a novel small-molecule antifungal agent recently approved in the United States for the topical treatment of toenail onychomycosis. The low molecular weight, slight water solubility, and boron chemistry of tavaborole maximize nail penetration after topical application, allowing for effective targeting of the infection in the nail bed. The efficacy of tavaborole is associated with its novel mechanism of action, whereby it inhibits the fungal leucyl-tRNA synthetase (LeuRS) enzyme. Because LeuRS is an essential component in fungal protein synthesis, inhibition of LeuRS ultimately leads to fungal cell death. Tavaborole is the first boron-based antifungal medication approved for the treatment of mild-to-moderate onychomycosis and presents patients with a new topical option. Previously, ciclopirox and efinaconazole were the only approved topical treatments for onychomycosis. This article details the properties that are at the core of the clinical benefits associated with tavaborole.