Combination adapalene-benzoyl peroxide for acne vulgaris is more effective than either therapy alone, according to the results of a new analysis.
The therapy reduced total lesion count after 12 weeks, regardless of a patient's initial number of lesions, according to Dr. Steven R. Feldman of the department of dermatology at Wake Forest University, Winston-Salem, N.C., and his colleagues.
Dr. Steven R. Feldman
The investigators pooled data from three multicenter, randomized clinical trials of similar design, totaling 3,853 patients. The three studies had four treatment groups (combination, adapalene only, benzoyl peroxide [BPO] only, and a gel vehicle).
The study investigators defined three subgroups based on lesion count: lowest 25%, middle 50%, and highest 25%. They found that efficacy of adapalene-benzoyl relative to its gel vehicle increased with number of lesions (J. Amer. Acad. Dermatol. 2011 [doi:10.1016/j.jaad.2010.03.036]).
Also, "adapalene-BPO was significantly more efficacious, compared with the monotherapies and vehicle in percent reduction of inflammatory, noninflammatory, and total lesions," the investigators wrote. "The superior efficacy of adapalene-BPO was also confirmed in all lesion count subgroups."
Total lesion counts in the three subgroups treated with combination therapy were reduced by 19%, 26%, and 29%, respectively.
The patients were aged 12 years or older and had 20-50 inflammatory lesions and 30-100 noninflammatory lesions on their face. Although 495 patients dropped out of the study, they were proportionally distributed among the three subgroups.
As for adverse events, tolerability was similar across all lesion count subgroups, with events being highest at week 1. The most common side effect was dry sin.
Dr. Feldman said in an interview that by subtracting the effect of the gel vehicle, he could more clearly determine the effect of the drug itself, since the study did not incorporate a placebo. However, he added, in clinical practice what is important is the full effect of the drug for the patient, aided by the gel vehicle.
He concluded that because the combination therapy showed similar overall improvement in the low- and high-lesion count groups, topical drugs are a viable first option even for severe acne cases. In addition, studies show that combination therapies simplify treatment for the patient and increase likelihood of adherence.
The study received funding from Galderma. Dr. Feldman disclosed receiving grant funding from Galderma, as well as serving as a speaker, investigator, and consultant for the pharmaceutical company. All of the other investigators for this study also disclosed relationships with Galderma.