A multicentre, single-blind, randomized comparison of a fixed clindamycin phosphate/tretinoin gel formulation (Velac) applied once daily and a clindamycin lotion formulation (Dalacin T) applied twice daily in the topical treatment of acne vulgaris.

Background: A successful phase III pilot study compared the efficacy and safety of a fixed clindamycin 1%/tretinoin 0.025% gel formulation (CTG; Velac gel) applied once daily and a clindamycin 1% lotion formulation (CLN; Dalacin T lotion) applied twice daily in the treatment of moderate to severe acne vulgaris.

Objectives: We aimed to follow up this study.

Methods: The two treatment regimens were compared in a multicentre, single-blind, randomized 12-week investigation of patients with moderate to severe acne vulgaris.

Results: At week 12, the mean percentage reduction in non-inflamed lesions (open and closed comedones) was greater in the CTG group compared with the CLN group (P = 0.05). Absolute reductions in open and closed comedones were also greater in the CTG group, consistent with the comedolytic activity of tretinoin. There was a significantly greater absolute reduction in inflamed lesions (pustules, papules and nodules) from baseline to both end-point (last observed efficacy outcome; P = 0.043) and week 12 (P = 0.018) in the CTG group compared with the CLN group. Evaluation of the calculated overall acne severity score, considering all five lesion subtypes, demonstrated a significantly greater mean percentage reduction in the CTG group compared with the CLN group, both at end-point (P = 0.01) and at week 12 (P < 0.01). The more subjective assessment of overall acne severity according to the Cook scale also demonstrated a significantly greater mean reduction in the CTG group than the CLN group after 12 weeks of therapy (P = 0.007). CTG had a more rapid effect on the onset of improvement compared with CLN; a 50% reduction in total lesion counts by day 60 was found in 77% of patients on CTG compared with 56% receiving CLN (P = 0.003). This was largely due to the reduction in open comedone counts (P = 0. 0006). For all other variables, CTG was at least as effective as CLN. Both treatments were well tolerated.

Conclusions: A single daily topical application of Velac gel was superior to Dalacin T lotion applied twice daily in reducing overall acne scores, and was faster acting. The simpler dosing regimen of Velac gel and its rapid effect are likely to have a positive effect on both patient compliance and cost.