Original Research

Lack of Significant Anti-inflammatory Activity With Clindamycin in the Treatment of Rosacea: Results of 2 Randomized, Vehicle-Controlled Trials

Author and Disclosure Information

Rosacea is a chronic inflammatory skin disease of the face. The objective of the studies described here was to evaluate the efficacy of clindamycin in the treatment of rosacea. Two multicenter, randomized, vehicle-controlled, phase 2 studies were conducted in participants with moderate to severe rosacea. Study A was a 12-week dose-comparison, 5-arm, parallel group comparison of clindamycin cream 1% or vehicle once or twice daily and clindamycin cream 0.3% once daily. Study B was a 2-arm comparison of twice daily clindamycin gel 1% versus vehicle gel. A total of 629 participants (study A, N=416; study B, N=213) were randomized. The results of these studies indicated that clindamycin cream 0.3% and 1% and clindamycin gel 1% were no more effective than the vehicle in the treatment of moderate to severe rosacea, suggesting clindamycin has no intrinsic anti-inflammatory activity in rosacea.

Practice Points

  • Clindamycin cream 0.3% and 1% and clindamycin gel 1% were no more effective than their respective vehicles in the treatment of moderate to severe rosacea.
  • Clindamycin may have no intrinsic anti-inflammatory activity in rosacea.


 

References

Rosacea is a chronic inflammatory skin disease characterized by central facial erythema with or without intermittent papules and pustules (described as the inflammatory lesions of rosacea). Although twice-daily clindamycin 1% solution or gel has been used in the treatment of acne, few studies have investigated the use of clindamycin in rosacea.1,2 In one study comparing twice-daily clindamycin lotion 1% with oral tetracycline in 43 rosacea patients, clindamycin was found to be superior in the eradication of pustules.3 A combination therapy of clindamycin 1% and benzoyl peroxide 5% was found to be more effective than the vehicle in inflammatory lesions and erythema of rosacea in a 12-week randomized controlled trial; however, a definitive advantage over US Food and Drug Administration-approved topical agents used to treat papulopustular rosacea was not established.4,5 Two further studies evaluated clindamycin phosphate 1.2%-tretinoin 0.025% combination gel in the treatment of rosacea, but only 1 showed any effect on papulopustular lesions.6-8 The objective of the studies reported here was to evaluate the efficacy and safety of clindamycin in the treatment of patients with moderate to severe rosacea.

Methods

Study Design

Two multicenter (study A, 20 centers; study B, 10 centers), randomized, investigator-blinded, vehicle-controlled studies were conducted in the United States between 1999 and 2002 in accordance with the Declaration of Helsinki, International Conference on Harmonisation Good Clinical Practice guidelines, and local regulatory requirements. The studies were reviewed and approved by the respective institutional review boards, and all participants provided written informed consent.

In study A, moderate to severe rosacea patients with erythema, telangiectasia, and at least 8 inflammatory lesions were randomized to receive clindamycin cream 1% or vehicle cream once (in the evening) or twice daily (in the morning and evening) or clindamycin cream 0.3% once daily (in the evening) for 12 weeks (1:1:1:1:1 ratio). All study treatments were supplied in identical tubes with blinded labels.

In study B, patients with moderate to severe rosacea and at least 8 inflammatory lesions were randomized in a 1:1 ratio with instructions to apply clindamycin gel 1% or vehicle gel to the affected areas twice daily (morning and evening) for 12 weeks.

Efficacy Evaluation

Evaluations were performed at baseline and weeks 2, 4, 8, and 12 on the intention-to-treat population with the last observation carried forward.

Efficacy assessments in both studies included inflammatory lesion counts (papules and pustules) of 5 facial regions--forehead, chin, nose, right cheek, left cheek--counted separately and then combined to give the total inflammatory lesion count (both studies), as well as improvement in the investigator global rosacea severity score (0=none/clear; 1=mild, detectable erythema with ≤7 papules/pustules; 2=moderate, prominent erythema with ≥8 papules/pustules; 3=severe, intense erythema with ≥10 to <50 papules/pustules; 3.5 [study A] or 4 [study B]=very severe, intense erythema with >50 papules/pustules). In study B, the proportion of participants dichotomized to success (a score of 0 [none/clear] or 1 [mild/almost clear]) or failure (a score of ≥2) on the 5-point investigator global rosacea severity scale at week 12 was evaluated. In study A, investigator global improvement assessment at week 12, based on photographs taken at baseline, was graded on a 7-point scale (from -1 [worse], 0 [no change], and 1 [minimal improvement] to 5 [clear]). In both studies, erythema severity was graded on a 7-point scale in increments of 0.5 (from 0=no erythema to 3.5=very severe redness, very intense redness). Skin irritation also was graded as none, mild, moderate, or severe.

Safety Evaluation

Safety was assessed by the incidence of adverse events (AEs).

Statistical Analysis

Studies were powered assuming 60% reduction in inflammatory lesion counts with active and 40% with vehicle, based on historical data from a prior study with metronidazole cream 0.75% versus vehicle; 64 participants were required in each treatment group to detect this effect using a 2-sided t test (&#945;=.017). Pairwise comparisons (clindamycin vs respective vehicle) were performed using the Cochran-Mantel-Haenszel test for combined lesion count percentage change.

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