Efficacy and Safety of a Fixed-Dose Combination Gel with Adapalene 0.1% and Clindamycin 1% for the Treatment of Acne Vulgaris (CACTUS): A Randomized, Controlled, Assessor-Blind, Phase III Clinical Trial

Abstract Background Combination therapy is required for the treatment of moderate acne vulgaris. However, patient compliance in applying multiple topical formulations is poor. Objective To assess the efficacy and safety of a fixed-dose combination gel with adapalene 0.1% and clindamycin 1% (adapalene-clindamycin) relative to adapalene 0.1% monotherapy and clindamycin 1% monotherapy in patients with moderate facial acne vulgaris. Methods This was a randomized, controlled, assessor-blind, phase III study conducted in patients with moderate facial acne vulgaris. Results A total of 1617 patients were enrolled. At week 12, patients in the adapalene–clindamycin gel treatment group showed a significant reduction in the percentage change from baseline in total lesion count (− 66.85%), compared with adapalene alone (− 50.82%) or clindamycin gel alone (− 57.61%). The difference in the least square means of the adapalene–clindamycin gel group and adapalene group, or clindamycin gel group was − 16.08% (95% CI − 19.95% to − 12.21%) and − 9.38% (95% CI − 13.25% to − 5.51%;), respectively. At week 12, 19.28% of participants who received adapalene–clindamycin gel achieved at least 2-grade improvement in IGA, versus 7.74% with adapalene gel (OR 3.05, 95% CI 1.93, 4.80) and 14.77% with clindamycin gel (OR 1.42, 95% CI 0.97, 2.07). The study also achieved all its secondary endpoints. Adverse event rates were mostly mild to moderate and comparable across the three treatment groups. Conclusion Adapalene 0.1%–clindamycin 1% combination gel is well tolerated and demonstrated superior efficacy over 0.1% adapalene gel monotherapy and 1% clindamycin gel monotherapy for the treatment of moderate acne vulgaris. Trial Registration ClinicalTrials.gov identifier NCT03615768.