Safety and Efficacy of Aminolevulinic Acid 10% Topical Gel versus Aminolevulinic Acid 20% Topical Solution Followed by Blue-light Photodynamic Therapy for the Treatment of Actinic Keratosis on the Face and Scalp: A Randomized, Double-blind Study

Abstract

Objective: Photodynamic therapy (PDT) using 10% 5-aminolevulinic acid (ALA) gel (GEL) has been shown to be highly effective for treating actinic keratosis (AK) but has only been studied using red-light activation. The goal of this study was to compare GEL and a 20% ALA solution (SOL) using blue-light activation under typical clinical conditions. Design: This double-blind, split-face study randomized subjects to GEL or SOL application to contiguous 25cm 2 fields containing 4 to 8 AK lesions on either side of the face or scalp (no curettage, 1-hour incubation, no occlusion) followed by blue light exposure (1,000 seconds, 417nm, 10J/cm 2 ). Participants: Forty adult subjects were treated on either the face (n=20) or scalp (n=20). Measurements: Primary outcomes included change in baseline AK lesions. Secondary outcomes included local skin reaction (LSR) scores and visual analog scale (VAS) pain scores. Results: Lesions treated with GEL were 97.1 percent cleared at Day 84 versus 94.9 percent for lesions treated with SOL ( p <0.001 vs. baseline); additionally, 86.8 percent of areas treated with GEL and 78.9 percent of areas treated with SOL showed 100-percent clearance ( p <0.001 vs. baseline). Mean VAS pain scores were minimal for the SOL and the GEL (25.4 vs. 28.5 and 16.1 vs. 19.3, respectively; p =nonsignificant). At three days after the first and second treatments, more significant LSRs were noted in areas treated with SOL, including erythema, crusting, and scaling/dryness. There were no significant adverse events observed. Conclusion: GEL was equivalent to SOL for clearing AK lesions on the face and scalp with blue-light PDT; however, SOL caused significantly more local skin reactions