A 12-week, multicenter, randomized, double-blind, parallel-group, vehicle-controlled trial of adapalene 0.1% (ADAP)/benzoyl peroxide 2.5% (BPO) gel versus the separate components was conducted in 1,670 patients with acne vulgaris. The treatments were administered once daily. The success rate was based on the frequency of patients achieving a "clear" or "almost clear" rating on the Investigator's Global Assessment (IGA). The percentage change in inflammatory lesions, noninflammatory lesions and total lesion counts was also recorded. At endpoint, the success rate was 37.9%, 21.8%, 26.7% and 17.9% in the ADAP/BPO, ADAP, BPO and placebo groups, respectively (P ≤ 0.001). The net beneficial effect of the combination was greater than the sum of the net benefits from ...