Efficacy and Safety of Efinaconazole 10% Topical Solution for Onychomycosis Treatment in Older Adults

Background: Toenail onychomycosis treatment is challenging, especially in older adults, due to slower nail growth, increased nail thickness, and greater likelihood of concomitant medication use and comorbidities (eg, diabetes, peripheral vascular disease, reduced renal function). Unfortunately, published efficacy and safety data in older adults are limited. Efinaconazole 10% solution has demonstrated efficacy and favorable tolerability in two phase 3 studies and in post hoc analyses of participant sex, ethnicity, age, baseline disease severity, and concurrent diabetes. Here, pooled post hoc analyses were conducted to evaluate efficacy and safety of efinaconazole in participants aged ≥65 years with mild to moderate onychomycosis. Methods: Data were pooled from 2 multicenter, randomized, double-blind, vehicle-controlled phase 3 studies (NCT01008033, NCT01007708) of participants aged 18-70 years with mild to moderate distal lateral subungual onychomycosis affecting ≥1 great toenail. Participants (n=1,655) were randomized (3:1) to topical efinaconazole 10% or vehicle applied once daily for 48 weeks, with a follow-up visit at week 52. Efficacy endpoints included rates of complete cure (0% clinical involvement of target toenail + negative potassium hydroxide [KOH] examination + negative fungal culture), mycologic cure (negative KOH + negative fungal culture), complete/almost complete cure (≤5% clinical involvement + mycologic cure), unaffected new toenail growth (change from baseline in unaffected toenail measurement), and clinical efficacy (<10% clinical involvement) at week 52. Adverse events (AEs) were also assessed. Only participants aged ≥65 years were included in these analyses (n=162 efinaconazole; n=56 vehicle). Results: At week 52, significantly more older adults treated with efinaconazole vs vehicle achieved a complete cure (13.6% vs 3.6%) or a complete/almost complete cure (19.1% vs 5.4%; P<0.05, both). Over half of participants treated with efinaconazole (59.2%) achieved mycologic cure vs 12.5% with vehicle (P<0.001). Least squares mean unaffected new nail growth was significantly greater with efinaconazole vs vehicle (3.9 mm vs 0 mm; P<0.001), and a quarter of participants achieved clinical efficacy with efinaconazole (25.3%) vs 14.3% with vehicle (P<0.05). Most treatment-emergent AEs with efinaconazole were mild to moderate in severity, and discontinuation rates were low (<4.5%), in line with the overall phase 3 populations. Conclusions: Topical efinaconazole 10% solution showed good efficacy and safety in participants aged ≥65 years with mild to moderate onychomycosis, despite possible age-related changes in nail growth. These results were in line with the overall phase 3 populations, demonstrating that efinaconazole is an efficacious treatment for older adults for whom there is a dearth of clinical data. Funding: Ortho Dermatologics