Background: Psoriasis vulgaris is commonly treated with topical corticosteroids and vitamin D analogues. Although potent and superpotent topical corticosteroids are very effective at clearing psoriasis, with short-term reactive treatment durations, symptoms usually recur after treatment discontinuation, necessitating long-term disease management strategies. A foam formulation of calcipotriol and betamethasone dipropionate (Cal/BD foam), consisting of calcipotriol 50 lg/g and betamethasone dipropionate 0.5 mg/g, is approved for the daily treatment of psoriasis for up to 4 weeks. Here, we describe a clinical trial protocol for evaluating the long-term safety and efficacy of twice-weekly Cal/BD foam as a proactive topical maintenance therapy for plaque psoriasis for up to 52 weeks. Objective: The aim of this trial was to evaluate the safety and efficacy of Cal/BD foam when Digital Features To view digital features for this article, go to