Efficacy and safety of add-on tacrolimus versus leflunomide in rheumatoid arthritis patients with inadequate response to methotrexate

Aim: To investigate the efficacy and safety of tacrolimus (TAC) versus leflunomide (LEF) when combined with methotrexate (MTX) in rheumatoid arthritis (RA) patients. Method: This was a 24-week multi-center, double-blind, randomized, non-inferiority study targeting RA patients with moderate to severe Disease Activity Score of 28 joints (DAS28 > 3.2) who showed inadequate response to MTX. Patients were randomized into TAC or LEF (add-on to MTX) groups. Initial daily doses of TAC and LEF were 1.5 and 10 mg, respectively, for 4 weeks and then doubled until the end of the study. The primary endpoint was DAS28 comparison at 24 weeks. Results: Eighty-seven patients were screened in 10 centers and 75 patients were randomized into two groups. Baseline demographics were comparable between TAC + MTX and LEF + MTX groups. The TAC + MTX group was non-inferior to the LEF + MTX group in terms of DAS28 at 24 weeks (mean difference of DAS28: −0.1812, 95% confidence interval: −0.8073, 0.4450). There was a greater number of adverse events in the LEF + MTX group (66 in LEF + MTX and 49 in TAC + MTX). Six patients presented with transaminitis in the LEF + MTX group compared with two patients in the TAC + MTX group. Conclusion: The efficacy of TAC combined with MTX was non-inferior to LEF + MTX. It had a reasonable safety profile in RA patients with moderate to severe disease activity (http://cris.nih.go.kr; KCT0000781).