RALEIGH, N.C. - Topical clindamycin phosphate 1.2%/tretinoin 0.025% gel was found to be significantly less irritating than benzoyl peroxide 2.5%/adapalene 0.1% gel was during the first 3 weeks of acne therapy, according to a double-blind, randomized, split-face comparative trial.
However, it should be noted that at all times, study participants scored their irritation as moderate or less with both medications. “Both products are pretty well tolerated. Nevertheless, looking at patient outcomes, clindamycin/tretinoin [Ziana]does seem to be less irritating than benzoyl peroxide/adapalene [Epiduo], which could be of clinical significance because it might [affect] patient compliance,” noted Dr. Renato Goreshi of the department of dermatology at the Oregon Health and Science University, Portland.
He presented a double-blind study involving 24 patients with mild to moderate facial acne at the annual meeting of the Society for Investigative Dermatology. All were white, and most were in their mid-20s.
Participants applied clindamycin/tretinoin to one side of their face and benzoyl peroxide/adapalene to the other side once daily for 3 weeks. They kept a daily record scoring burning/stinging and itching on a 0-3 scale. In addition, investigators measured transepidermal water loss and conducted Investigator’s Global Assessments of dryness/scaling and erythema at baseline and weekly thereafter.
The primary study outcome was transepidermal water loss, a reliable and validated measure of epidermal barrier disruption. Transepidermal water loss was significantly greater at weeks 1, 2, and 3 on the benzoyl peroxide/adapalene–treated side of the face.
The benzoyl peroxide/adapalene–treated side also scored threefold higher on the patients’ self-assessed rating of burning/stinging, and twice as high on itching.
“This isn’t entirely surprising, since in studies in atopic dermatitis we also see that there’s a correlation between higher transepidermal water-loss scores and increased pruritus, which is what we saw here,” Dr. Goreshi said.
The difference in composite irritancy scores was larger in the first half of the study than in the second half, when scores headed toward convergence.
Investigators found no significant difference between the two products in erythema or dryness/scaling.
There was also no significant difference between the two topical agents in terms of reduction of acne lesion counts. However, one wouldn’t expect to see significant differences during this short of a study, which was designed to look at irritancy, not efficacy, Dr. Goreshi noted.
The study was funded by Medicis, which markets Ziana.