Clinical efficacy and safety comparison of adapalene gel and tretinoin gel in the treatment of acne vulgaris: Europe and U.S. multicenter trials

Background: Adapalene is a new chemical entity that exhibits tretinoin-like activities in the terminal differentiation process. Objective: We evaluated a dose range effect of two concentrations of adapalene gel as acne treatment and compared adapalene 0.1% gel with tretinoin 0.025% gel in the treatment of acne patients in two large multicenter studies. Methods: Multicenter, investigator-masked, parallel group studies including 89 acne patients in the dose range study and 591 patients in the concurrent controlled studies were conducted. Results: Adapalene gel 0.1% was significantly more effective in treating acne lesions than 0.03% adapalene gel. Adapalene gel 0.1% was significantly more effective than 0.025% or tretinoin gel in one study and of the same effectiveness in the other study. Adapalene gel was always better tolerated than tretinoin gel. Conclusion: Adapalene 0.1% gel is a safe and effective treatment of acne vulgaris. (J Am Acad Dermatol 1997;36:S126-34.)