Efficacy and safety of mufemilast in patients with Behçet's syndrome: a phase 2 randomised clinical trial.

Abstract

This study aimed to evaluate the efficacy and safety of mufemilast, a novel small-molecule selective phosphodiesterase 4 (PDE4) inhibitor, in patients with Behçet's syndrome (BS). Patients diagnosed with BS according to the International Diagnostic (Classification) Criteria for Behçet's Disease 2013 and with active oral ulcers were eligible. Patients were randomly assigned to mufemilast (45 mg or 60 mg) or placebo, administered orally twice daily for 12 weeks. The primary endpoint was the area under the curve (AUC) for the number of oral ulcers from baseline to week 12. Safety was measured in all patients who received at least 1 dose of the study drug (ClinicalTrials: NCT04609397). Ninety patients were randomly assigned to the mufemilast 45 mg, 60 mg, or placebo groups (29, 31, and 30, respectively). The least-squares mean difference in AUC_0-12 for oral ulcers between the 45 mg and 60 mg groups and the placebo was -104.8 (95% CI, -156.3 to -53.2; P < .001) and -142.5 (95% CI, -192.4 to -92.7; P < .001), respectively. The visual analogue pain scores and time to ulcer-free remission were significantly improved with mufemilast (P < .001). PDE4-related side effects were transient and resolved spontaneously, and discontinuation rates were low (7% for 45 mg, 7% for 60 mg, and 3% for placebo). No serious adverse events were reported related to the drug. Among patients with oral ulcers associated with BS, mufemilast significantly reduced the number of oral ulcers, improved pain scores, and induced significantly more ulcer-free remissions compared with placebo, with an acceptable safety profile.