Clindamycin-tretinoin combo effective for acne

July 1, 2005

National Report - Pooled results from two phase 3 clinical trials demonstrate the efficacy and safety of an investigational acne treatment combining clindamycin and tretinoin in a hydrogel base (Velac, Connetics), James J. Leyden, M.D., reported at the 63rd Annual Meeting of the American Academy of Dermatology.

The product contains clindamycin 1 percent and tretinoin 0.025 percent. To achieve solubilization of both active ingredients and assure a good shelf life at room temperature, a novel aqueous hydrogel vehicle was developed.

The combination product was evaluated in two identically designed, 12-week, multicenter controlled studies in which patients were randomized 2:2:2:1 to once-daily application of the combination product (n = 634), clindamycin 1 percent hydrogel (n = 635), tretinoin 0.025 percent hydrogel (n = 635) or vehicle hydrogel (n = 315).

Value borne out "More than 30 years ago, I put forth the concept that the combination of an antibiotic with a retinoid would be more effective than monotherapy with either agent alone, considering that the primary modes of action of each component of the dual regimen address different aspects in the pathophysiology of acne," says Dr. Leyden, professor of dermatology, University of Pennsylvania School of Medicine, Philadelphia.

"The value of combination treatment was underlined by an expert international panel that was brought together to develop consensus recommendations on the treatment of acne (J Amer Acad Dermatol 2003;49(suppl 1):S1-37), and are once again well-illustrated by the results of this study."

"Patients who use this combination can expect that it will be at least as well-tolerated as a topical retinoid alone, but will enjoy the convenience of applying a single product only once a day. In everyday use, we would expect that latter advantage should result in improved compliance that, in turn, should maximize efficacy," he adds.

Patients eligible for participation in the phase 3 study had to be at least 12 years old and have 17 to 40 facial inflammatory lesions and 20 to 150 facial non-inflammatory lesions. Analyses of baseline demographic and clinical characteristics showed no significant differences between groups in age, gender, race or lesion counts.

The pooled population had a mean age of about 19 years, about half were 12 to 16 years old, and they were nearly equally divided by gender. About two-thirds of the participants were Caucasian and about 20 percent were black. Mean total lesion count was about 77, with a 2:1 ratio between non-inflammatory and inflammatory lesions.

Lesion counts reduced Efficacy was also evaluated with an investigator's static global assessment of acne severity, and the results for that endpoint considering proportions of patients achieving "clear" or "almost clear" status also showed statistically significant differences favoring the clindamycin-tretinoin combination over each of its comparators (P < 0.0001). At week 12 in the ITT analysis, 37 percent of patients in the combination gel group had clear or almost clear skin, compared with 27 percent of patients using clindamycin gel, 25 percent of patients in the tretinoin group and 14 percent of the vehicle controls.

The safety review revealed that nearly 90 percent of patients experienced no adverse events. Application site dryness, desquamation, burning, erythema and pruritus were the only events that occurred in >1 percent of patients. Rates for each of those events were ≤2 percent in the vehicle and clindamycin gel groups and somewhat higher in the combination gel and tretinoin groups (3 to 9 percent), but nearly identical in the latter two groups.