Efinaconazole 10% solution is used for the topical treatment of onychomycosis of the toenails (tinea unguium, ringworm of the nail) caused by Trichophyton rubrum or T. mentagrophytes.
Safety and efficacy of topical efinaconazole for the treatment of onychomycosis were evaluated in 2 multicenter, double-blind, randomized, vehicle-controlled, phase 3 studies that included 1655 adults 18-70 years of age who had 20-50% clinical involvement of affected toenails without dermatophytomas or lunula (matrix) involvement. Efinaconazole 10% solution or vehicle solution was applied to affected toenails once daily for 48 weeks. Primary efficacy end point was complete cure (0% clinical involvement of target toenails plus negative potassium hydroxide [KOH] microscopic examination and negative fungal culture) at week 52 (i.e., 4 weeks after discontinuance). Secondary efficacy end points included complete or almost complete cure (5% or less involvement of affected target toenail and negative KOH microscopic examination and negative fungal culture) and mycologic cure (negative KOH microscopic examination and negative fungal culture) at week 52. Efinaconazole was superior to vehicle solution in the topical treatment of onychomycosis in both studies. Complete cure rate for efinaconazole versus vehicle solution was 17.8 versus 3.3% in study 1 and 15.2 versus 5.5% in study 2. Complete or almost complete cure rate for efinaconazole versus vehicle solution was 26.4 versus 7% in study 1 and 23.4 versus 7.5% in study 2. Mycologic cure rate for efinaconazole versus vehicle solution was 55.2 versus 16.8% in study 1 and 53.4 versus 16.9% in study 2.
Onychomycosis is a fungal infection of the nails generally caused by dermatophytes (usually T. rubrum or T. mentagrophytes), but sometimes caused by nondermatophytic fungi (e.g., Acremonium, Aspergillus, Candida albicans, Fusarium, Scopulariopsis, Scytalidium). Onychomycosis of the toenails frequently involves several nails, and many patients also have tinea pedis (athlete's foot), especially dry-type (moccasin-type) tinea pedis. Left untreated, onychomycosis may result in progressive destruction and deformity of affected nails and possibly may lead to more widespread cutaneous involvement with spread to other digits and body areas. Selection of the most appropriate regimen for treatment of onychomycosis depends on the severity and extent of nail involvement, organisms involved, reported cure rates, adverse effects, drug interactions, cost, and patient and clinician preference. Onychomycosis generally is treated using an oral antifungal (e.g., itraconazole, terbinafine) and adjunctive physical modalities (nail trimming, aggressive debridement, nail avulsion) with or without a topical antifungal. Use of a topical antifungal alone (e.g., ciclopirox) with adjunctive physical modalities generally has been associated with lower cure rates, possibly because of poor patient compliance with the lengthy duration of treatment and poor drug penetration through the nail plate. Although topical antifungals with improved nail penetration are now available for treatment of onychomycosis (e.g., efinaconazole, tavaborole), additional study is needed to evaluate the comparative efficacy and safety of these antifungals and other topical antifungals or oral antifungals used for treatment of onychomycosis.