To compare the efficacy and safety of tacrolimus and mizoribine in patients with rheumatoid arthritis (RA).
Adult patients with RA with an insufficient response to at least one disease modifying antirheumatic drug (DMARD) were randomized to receive 28 weeks of double-blind treatment with tacrolimus 3 mg once daily or mizoribine 50 mg three times daily. The primary efficacy endpoint was the American College of Rheumatology 20% (ACR20) response. Safety was evaluated by adverse events.
A total of 204 patients were enrolled for study (103 in the tacrolimus group, 101 in the mizoribine group). Significantly more patients receiving tacrolimus achieved an ACR20 response compared with mizoribine (48.5 vs 10.0%, respectively; p = 0.001). Tacrolimus was also superior to mizoribine in ACR50 and ACR70 response rate, tender and painful joint counts, swollen joint counts and patient and physician assessments of pain, disease activity, and patient's physical function assessment based on the Modified Health Assessment Questionnaire (p < 0.001). Adverse events were more frequent in the tacrolimus group than the mizoribine group (65.0 vs 59.4%); however, there were no statistically significant differences between treatment groups.
Tacrolimus improves RA symptoms to a significantly greater extent than mizoribine in patients with RA inadequately controlled with at least one prior DMARD. Tacrolimus has the potential to be a useful and highly effective treatment for RA.