Tavaborole 5% Topical Solution for the Treatment of Toenail Onychomycosis in Pediatric Patients: Results from a Phase 4 Open-Label Study

Background: This study was designed to evaluate the safety, tolerability, pharmacokinetics (PK), and efficacy of tavaborole in pediatric patients. Study Design: In this open-label, single-arm study, pediatric patients (aged 6 to <17 years) with distal subungual onychomycosis affecting ≥20% of the target great toenail applied tavaborole once daily to all affected toenails (2 drops/great toenail, 1 drop/other toenail) for 48 weeks. In addition, a maximal-use subgroup (aged 12 to <17 years) applied tavaborole to all 10 toenails and ≤2 mm of surrounding skin for the first 28 days. Results: Treatment-emergent adverse events (TEAEs) were reported by 55.6% of patients; the most frequently reported (≥5% of patients) were nasopharyngitis, contusion, sinusitis, and vomiting. Most TEAEs and local treatment reactions (LTRs) were mild or moderate and considered unrelated to treatment. There was 1 serious AE (severe appendicitis, considered unrelated to treatment) and there were no deaths, discontinuations because of AEs, or dose adjustments because of AEs. The most frequently reported LTRs were erythema and scaling. The incidence of LTRs diminished over time. Tavaborole was absorbed systemically, and plasma concentrations were measurable. The PK parameters determined in this study under maximal-use conditions indicate that steady state was achieved within the study period. For efficacy, 8.5% of patients achieved complete cure (clear nail and negative mycology [negative fungal culture and negative potassium hydroxide wet mount]) at week 52, and 14.9% achieved complete/almost complete cure at week 52 (clear or almost clear nail [≤5% dystrophic or discolored distal toenail plate] and negative mycology). Conclusion: Tavaborole was well tolerated in this pediatric population, and safety, PK, and efficacy profiles were comparable with those in adults. Trial registration: ClinicalTrials.gov identifier: NCT03405818 J Drugs Dermatol. 2019;18(2):190-195.