Adapalene-benzoyl peroxide once-daily, fixed-dose combination gel for the treatment of acne vulgaris: a randomized, bilateral (split-face), dose-assessment study of cutaneous tolerability in healthy participants.

Combination therapy is an effective approach to simultaneously target multiple pathogenic factors of acne. International consensus guidelines recommend the use of topical retinoids and benzoyl peroxide (BPO) for acne treatment. These drugs are often prescribed as a free combination without any safety concern associated with antibiotic use. A 3-week, randomized, controlled, investigator-blinded, single-center, bilateral (split-face), dose-assessment study was conducted comparing the cutaneous tolerability of 2 adapalene-BPO fixed-dose combination products versus various concentrations of BPO monotherapy applied once daily. Sixty healthy participants were randomized to one of the following treatment groups: adapalene 0.1%-BPO 2.5% combination product versus BPO 2.5% monotherapy; adapalene 0.1%-BPO 2.5% combination product versus BPO 5% monotherapy; adapalene 0.1%-BPO 5% combination product versus BPO 5% monotherapy; and adapalene 0.1%-BPO 5% combination product versus BPO 10% monotherapy. Assessments included total sum score (TSS) of irritation signs/ symptoms (erythema, scaling/desquamation, dryness, pruritus, stinging/burning) averaged over all postbaseline visits, individual irritation signs/symptoms (worst score), and adverse events. The overall cutaneous tolerability profile of the adapalene 0.1%-BPO 2.5% combination product was better than the combination with BPO 5% and similar to BPO 2.5% or 5% monotherapy. The combination product with BPO 5% induced significantly more irritation than BPO 5% monotherapy (P < .001) or BPO 10% monotherapy (P = .001). In conclusion, the new fixed-dose adapalene 0.1%-BPO 2.5% combination product provided the best overall cutaneous tolerability profile relative to BPO monotherapy.