PSO-LONG: Design of a Novel, 12-Month Clinical Trial of Topical, Proactive Maintenance with Twice-Weekly Cal/BD Foam in Psoriasis

Background: Psoriasis vulgaris is commonly treated with topical corticosteroids and vitamin D analogues. Although potent and super-potent 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 μg/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 applied twice weekly for up to 52 weeks as proactive maintenance therapy, with the goal of preventing or delaying disease relapse as long as possible while minimizing adverse effects. Methods: Once-daily Cal/BD foam treatment responders from an initial 4-week open-label period were randomized to receive Cal/BD foam or foam vehicle applied to previously cleared plaques twice weekly for up to 52 weeks. In case of relapse, affected subjects in either group received rescue therapy with once-daily Cal/BD foam for 4 weeks on active areas. Thus, the trial (NCT02899962) compared the long-term use of Cal/BD foam in a proactive approach with a conventional, reactive approach. Planned Outcomes: Efficacy endpoints included the time to first relapse, the number of relapse-free days, and the number of relapses during the maintenance phase. Safety assessments included adverse events, incidence of rebound, local safety and tolerability scores, and effects on calcium metabolism and hypothalamic–pituitary–adrenal axis function. Trial registration: ClinicalTrials.gov identifier, NCT02899962.