Onychomycosis is a fungal infection of the fingernails and toenails that results in thickening, discoloration, splitting of the nails and lifting of the nail from the nail bed. The disease is caused by dermatophytes and has a high incidence within the general population, especially among older individuals. Present treatment options include both oral and topical drugs, with oral therapies giving better outcomes; however, neither of these treatment options provides high cure rates that are durable. The difficulty in treating onychomycosis results from the deep-seated nature of the infection within the nail unit (nail plate, nail bed and surrounding tissue) and the inability of drugs to effectively reach all sites. Ongoing drug development activities have focused on novel delivery technologies to facilitate penetration of existing antifungal drugs through the nail plate and on the discovery of inherently penetrable antifungals. AN-2690 represents an oxaborole antifungal that is designed to penetrate the nail plate and is showing promising results in clinical trials.