Efinaconazole 10% solution: a new topical treatment for onychomycosis: contact sensitization and skin irritation potential.

BACKGROUND Onychomycosis is a chronic condition that often requires long-term management to eradicate the causative fungus, allow a healthy nail to grow, and prevent relapse. As a successful outcome depends highly on patient adherence with treatment, a low risk of periungual skin irritation with topical medication is clinically relevant. OBJECTIVES To study the potential for efinaconazole 10% solution and its corresponding vehicle to induce delayed contact skin sensitization and evaluate its skin irritation potential. METHODS Efinaconazole 10% solution and its vehicle were studied in 239 healthy volunteers for the potential to induce contact skin sensitization. This included a series of induction, challenge, and re-challenge phases. An additional 21-day cumulative irritation study was undertaken in 35 healthy volunteers to compare three concentrations of efinaconazole (1%, 5%, and 10%), vehicle, and positive/negative controls. RESULTS There was no evidence of induced contact sensitization under occlusive, semi-occlusive, and open (open rub-in) applications of efinaconazole 10% solution. Efinaconazole 1%, 5%, and 10% solutions have mean cumulative irritancy indices of 1.12, 1.26, and 1.18, respectively, where a range of >0 to ≤1 is classified as "mildly irritating." RESULTS were comparable to vehicle (1.04). CONCLUSION Efinaconazole 10% solution did not cause contact sensitization and induced only minimal skin irritation in the studies completed.