Leflunomide in psoriatic arthritis: results from a large European prospective observational study.

To determine the "real-world" clinical effectiveness and safety of leflunomide in patients with psoriatic arthritis (PsA). This prospective, multinational 24-week observational study involved adult patients with active PsA who initiated treatment with leflunomide. Patients were evaluated at baseline, 12 weeks, and 24 weeks. The primary outcome was response as assessed by the Psoriatic Arthritis Response Criteria (PsARC) in patients with pre- and posttreatment data. A modified PsARC response analysis included patients with joint counts, but no severity scores. Other effectiveness evaluations included global assessments, fatigue, pain, skin disease, dactylitis, and nail lesions. All patients were evaluated for safety. A total of 514 patients were enrolled in this study (mean age 50.7 years, mean disease duration 6.1 years). In the primary effectiveness analysis, 380 (86.4%) of 440 patients (95% confidence interval 82.8%-89.4%) achieved a PsARC response at 24 weeks. Significant improvements were observed in tender and swollen joint scores and counts, patient and physician global assessments, fatigue, pain, skin disease, dactylitis, and nail lesions. The discontinuation rate was 12.3%. Ninety-eight adverse drug reactions occurred in 62 (12.1%) patients; 3 drug reactions were serious (2 increased liver enzymes, 1 hypertensive crisis). Leflunomide is an effective and well-tolerated option for PsA in daily clinical practice, with beneficial effects on peripheral arthritis and on other PsA manifestations, including pain, fatigue, dactylitis, and skin disease.