Randomized, Observer-Blind, Split-Face Study to Compare the Irritation Potential of 2 Topical Acne Formulations Over a 14-Day Treatment Period

This randomized, observer-blind, split-face study assessed the irritation potential and likelihood of continued use of clindamycin phosphate 1.2%–benzoyl peroxide (BPO) 2.5% gel or adapalene 0.1%–BPO 2.5% gel once daily over a 14-day treatment period in 21 participants (11 males; 10 females) with acne who were 18 years or older. Investigator clinical assessment (erythema and dryness) and self-assessment (dryness and burning/stinging) were performed at baseline and each study visit (days 1–14) using a 4-point scale (0=none; 3=severe). Transepidermal water loss (TEWL) and corneometry measurements were performed at baseline and days 3, 5, 7, 9, 11, and 14. Lesions were counted at baseline and on day 14. Participant satisfaction questionnaires were completed on days 7 and 14. At the end of the study, investigators reported none or only mild erythema in 86% (18/21) of participants treated with clindamycin phosphate 1.2%–BPO 2.5% gel compared with 62% (13/21) of participants treated with adapalene 0.1%–BPO 2.5% gel. No severe erythema was reported with clindamycin phosphate 1.2%–BPO 2.5% gel. Adapalene 0.1%–BPO 2.5% gel was prematurely discontinued due to severe erythema in 1 participant on day 5 and a second participant on day 9. Additionally, 2 more participants reported severe erythema on day 14. Mean erythema scores were 0.9 (mean change from baseline, 0.7) with clindamycin phosphate 1.2%–BPO 2.5% gel and 1.4 (mean change from baseline, 1.3) with adapalene 0.1%–BPO 2.5% gel on day 14 (P<.05 for days similar results were seen with dryness. mean scores change from baseline and respectively self-assessment tewl corneometry underscored the investigator clinical assessment. participant preference likelihood of continued usage was greater clindamycin phosphate gel. use efficacy treatment acne influenced by potential product to cause irritation preferences. more pronounced severe adapalene undoubtedly as a result participants preferred gel likely continue product.>