Clinical Trial Designs for Topical Antifungal Treatments of Onychomycosis and Implications on Clinical Practice

Abstract

There currently are 3 topical agents approved by the US Food and Drug Administration (FDA) to treat onychomycosis: tavaborole, efinaconazole, and ciclopirox. The phase 3 clinical trial designs for these treatments and their notable differences make it difficult for clinicians to interpret the data into clinical practice. For example, the primary end point predominantly used to assess efficacy in all the trials is complete cure, defined as no involvement of the nail plus mycologic cure; also, a notable number of patients fail to achieve a complete cure despite clear improvement in the nail. Despite close similarities in the end points and overall design of the clinical trials used for these agents, differences in design are notable, including the age range of participants, the range of mycotic nail involvement, the presence/absence of tinea pedis, and the nail trimming/debridement protocols used. The differences in clinical trial designs for the 3 FDA-approved topical agents and the lack of head-to-head studies makes efficacy interpretation and comparison inappropriate. This article reviews the phase 3 clinical trials that led to FDA approval of these agents, focusing on their similarities and differences.