An Open-Label, Phase I, Single-dose Study to Evaluate the Safety, Tolerability, and Pharmacokinetics of Fexofenadine Topical Lotion 1% in Normal Healthy Volunteers

Atopic Dermatitis (AD), or eczema, affects ~230 million individuals worldwide annually, with up to 20% of children and up to 3% of adults affected. The current treatment for mild and moderate forms often involves topical corticosteroids, which have limitations. Fexofenadine is an FDA-approved over-the-counter antihistamine product with a 25-year safety history and the capability to modulate multiple proinflammatory cytokines involved with AD pathophysiology. This study assesses the safety, tolerability, and pharmacokinetic (PK) profile of fexofenadine HCl topical lotion 1.0% (FEX). This open-label Phase I study included 12 healthy males aged 18-45 who received a single application of 11 g of the lotion to cover 54% of their body surface area. Safety, sensorial, and tolerability assessments occurred throughout the study period. Blood sample collection occurred at (0 hours [pre-dose] and at 1, 4, 8, 12, 16, 24, 36, 48, 60, and 72-hours post-dose) after application for assessment of PK. Over 90% of participants reported no adverse reaction or tolerability issue. One participant reported mild topical discomfort involving itch, which was transient and resolved. PK parameters included mean Cmax at 0.995+- 1.758 ng/mL, Tmax at 12.33 +- 6.48 hr, and AUC0-t of 12.44 +- 17.78 ng*hr/mL. The single-dose administration of FEX was safe, well-tolerated, showed limited systemic absorption, and supported once-daily dosing. These observations will serve as the basis for further clinical development.