BACKGROUND: Roflumilast is a targeted inhibitor of phosphodiesterase (PDE)-4 and has been approved for treatment of severe chronic obstructive pulmonary disease for more than a decade. Generic versions are available in the United States. PDE-4 is involved in the psoriasis pathogenesis, but the efficacy and safety of oral roflumilast in patients with psoriasis have not previously been studied.

METHODS: A company-independent, multicenter, randomized, double-blind, placebo-controlled trial (ClinicalTrials.govNCT04549870). Patients were randomized 1:1 to receive monotherapy with oral roflumilast 500 μg once daily or placebo. At week 12, placebo patients were switched to open-label roflumilast through week 24. The primary endpoint was a 75% or greater reduction from baseline in the psoriasis area and severity index (PASI75) at week 12.

FINDINGS: In all, 46 patients were randomized (roflumilast, n = 23; placebo, n = 23). At week 12, significantly more patients in the active arm achieved PASI75 (8 of 23 patients [35%]) vs. placebo (0 of 23 patients [0%], with a difference vs. placebo of 8 [35%] patients, 95% CI: 3 [13%]-13 [57%] patients) (p = 0.014). At week 24, 15 (65%), 10 (44%), 5 (22%), and 2 (9%) of patients treated with roflumilast from week 0 had PASI50, PASI75, PASI90, and PASI100 responses (key secondary endpoints), respectively. The most prevalent, drug-related adverse events in both treatment groups were transient gastrointestinal symptoms, weight-loss, headache, and insomnia. A total of three patients (roflumilast n = 2; placebo, n = 1) discontinued therapy due to adverse events.

INTERPRETATION: Oral roflumilast was efficacious and safe in treating moderate-to-severe plaque psoriasis over 24 weeks. With generic versions available, this drug may represent an inexpensive and convenient alternative to established systemic psoriasis treatments.

FUNDING: Financial support was received from Herlev and Gentofte Hospital, University of Copenhagen, and independent grants from private foundations in Denmark. No pharmaceutical company, including the market authorization holder of roflumilast, was involved in the study at any point.