In the treatment of acne, no single topical agent acts on all major 4 pathophysiologic mechanisms of it. Combination treatment with agents of different modes of action produces better outcomes than monotherapy, and a fixed-dose combination
of adapalene (ADA) 0.1%/benzoyl peroxide (BPO) 2.5% gel was recently developed. Though its superior efficacy to monotherapy
of either drug alone has been reported in many articles,1 most studies were conducted in Western countries, and there has been no article regarding Asian population. To investigate the efficacy and safety of ADA/BPO gel in Asian acne patients and to compare it with ADA gel, we conducted a 12-week, split-face, observer-blinded, comparison study of ADA/BPO gel and ADA gel for Korean acne patients. The study protocol was approved
by the Pusan National University Hospital Institutional Review Board (No. 2010046), and all participants provided written
informed consents before entering the study. The treatment efficacy was evaluated at weeks 0, 1, 2, 4, 8, and 12, by counting the lesions, taking photographs, and rating subjective satisfaction
and adverse reactions. Twenty-seven subjects were enrolled in the study, and 4 subjects discontinued: 3 were lost to follow-up and 1 was voluntarily withdrawn. The remaining 23 patients completed the study, and their baseline characteristics and the summary of study results are noted in Table 1 and Figure 1.
All patients showed a progressive decline in the number of inflammatory
and noninflammatory lesions, and the decrease was more remarkable in ADA/BPO-treated side at the end of study (P<.001). Not only the decrement of absolute lesion counts, but also the patient proportion classified as much improved were significantly superior in the ADA/BPO-treated group (P=.023). Though more patients complained about local irritations during early treatment in ADA/BPO-treated group, all symptoms were tolerable and the prevalence of irritation did not differ between both sides (P>.05). This irritation decreased with time and resolved within 6 weeks.
ADA binds to epidermal retinoic acid receptor γ and has not only anticomedogenic, comedolytic, anti-inflammatory activities, but also immunomodulatory activity by decreasing Toll-like receptor
2 expression, increasing CD1d expression, and decreasing interleukin-10 expression.1 The main action of BPO is its antibacterial
effect on Propionibacterium acnes by generating reactive oxygen species, and it can be used with less concern about antibiotic
resistance.2 The synergistic activity of aforementioned 2 agents has been reported in many Western articles, and its nega-