Efficacy of low-dose tacrolimus added to methotrexate in patients with rheumatoid arthritis in Japan: a retrospective study

The aim of this study was to assess if low-dose tacrolimus is efficacious for the treatment of rheumatoid arthritis (RA) when combined with methotrexate (MTX). The clinical courses of 32 RA patients who received tacrolimus plus MTX were analyzed retrospectively. Disease activity and clinical response were evaluated by DAS28 (disease activity score of 28 joints) and EULAR (European League Against Rheumatism) response criteria. Tacrolimus was started at 1 mg/day in five patients, 1.5 mg/day in 24 patients, and three mg/day in 3 patients. At six months, tacrolimus was continued at 1-2 mg/day in 27 of 32 patients, but was discontinued in five cases who showed no or inadequate response. Of the 32 patients, 47% were evaluated as having a moderate or good response at one month of tacrolimus therapy, and 72% at six months. No serious adverse events were observed. Our results suggest that the addition of tacrolimus at low dose to MTX for the treatment of patients with moderately active RA appears to be highly efficacious. Further studies are required for the appropriate use of this expensive immunosuppressant in the treatment of RA.