A randomized, single-blind comparison of topical clindamycin + benzoyl peroxide and adapalene in the treatment of mild to moderate facial acne vulgaris.

BACKGROUND: Antibiotics are often combined with other agents to provide topical acne treatments that are effective against both inflammatory and noninflammatory lesions and minimize the development of antibiotic resistance. Retinoids and associated treatments also have anti-inflammatory activity and decrease microcomedo formation. To date, few direct comparisons of these different acne treatments have been conducted.

OBJECTIVES: To compare the clinical effectiveness of two treatments for facial acne: a ready-mixed once-daily gel containing clindamycin phosphate 10 mg mL(-1) + benzoyl peroxide 50 mg mL(-1) (CDP + BPO; Duac; Stiefel, High Wycombe, U.K.) and a once-daily gel containing adapalene 0.1% (ADA; Differin; Galderma, Watford, U.K.).

METHODS: In this assessor-blind, randomized study; 65 patients were treated with CDP + BPO once daily and 65 patients with ADA once daily. The treatment period was 12 weeks and lesion counts, acne grade and global improvement were assessed at weeks 1, 2, 4, 8 and 12.

RESULTS: CDP + BPO showed an earlier onset of action with a faster significant reduction in inflammatory and total lesion counts than ADA. A between-group comparison of the percentage change from baseline showed that CDP + BPO was statistically significantly superior to ADA from week 1 onwards both for inflammatory lesions (P < or = 0.001) and for total lesions (P < or = 0.004). While 76% of inflammatory lesions remained at week 2 for patients using ADA, in contrast, only 55% of inflammatory lesions remained at week 2 in the CDP + BPO group, resulting in a treatment effect of 1.38. Thus CDP + BPO removed 38% more inflammatory lesions than ADA at this timepoint. The trend in favour of CDP + BPO, although less marked, continued to the end of the study. CDP + BPO was better tolerated than ADA, with a greater proportion of ADA-treated patients experiencing treatment-related adverse events. Adjunctive topical or oral agents and their impact on acne were not studied in this trial. Due to product differences, this study could not be double blinded but was only single (assessor) blinded.

CONCLUSIONS: CDP + BPO and ADA are both effective treatments for acne, but CDP + BPO has a significantly earlier onset of action, is significantly more effective against inflamed and total lesions and is better tolerated, which should improve patient compliance.