Efinaconazole solution in the treatment of toenail onychomycosis: a phase 2, multicenter, randomized, double-blind study.

Onychomycosis is a common nail infection that is difficult to treat successfully. The prevalence increases with age and is associated with diabetes. Oral treatments are limited by drug interactions and potential hepatotoxicity; topical treatments, by modest efficacy.We investigated the efficacy and safety of a solution using a novel topical triazole antifungal, efinaconazole, in distal lateral subungual onychomycosis (DLSO).Multicenter, randomized, double-blind, vehicle-controlled phase 2 study in mild to moderate toenail DLSO (n=135). Subjects randomized (2:2:2:1 ratio) to receive efinaconazole 10% solution (with or without semiocclusion), efinaconazole 5% solution, or vehicle, once daily for 36 weeks, with one 4-week posttreatment follow-up (week 40). Efficacy assessments included complete cure, mycologic cure, clinical efficacy, and other assessments of overall treatment effectiveness. No efficacy variables were designated as primary.At follow-up, complete cure was numerically higher in all active groups (16%-26%) compared with vehicle (9%). Mycologic cure rates with efinaconazole 10% semiocclusion, efinaconazole 10%, and efinaconazole 5% were 83%, 87%, and 87%, respectively. Efinaconazole 10% (with or without semiocclusion) demonstrated significantly greater clinical efficacy and treatment effectiveness when compared with vehicle (P=.0088 and .0064; .0056 and .0085, respectively, for both efinaconazole 10% groups). Adverse events were generally similar and mild. Local-site reactions were restricted to few subjects and did not differ meaningfully from those produced by vehicle.This study provided evidence that once-daily efinaconazole 10% solution (with or without semiocclusion) applied topically for 36 weeks was more effective than vehicle in treating DLSO and was well tolerated. Based on these results, efinaconazole 10% solution was chosen for the phase 3 development program.