High-dose Intermittent Administration of Mizoribine in Rheumatoid Arthritis Patients responded poorly to Methotrexate ―Comparing with daily administration of Mizoribine.―

Abstract

    To investigate the effectiveness of high-dose intermittent additive administration of mizoribine (MZB), 36 outpatients with RA who had insufficient responses to methotrexate (MTX) were enrolled in this study. 25 patients received additional use of MZB 300 mg once or twice a week (Group A). 11 other patients were treated with 100 or 150 mg/day of MZB concomitantly (Group B). We compared Group A with Group B in DAS28 (CRP) as the primary efficacy endpoint of this study. The response rate (good＋moderate) of DAS28 (CRP) was 44.0% in group A and 18.2% in B group at 3-4 months after MZB treatment. Group A demonstrated a significantly higher rate of improving anemia. The frequency of adverse effects and the abnormal test values of the 2 groups was low rate and not different. In patients with a CRP improvement rate of over 30％ at 2-4 months after the start of treatment, the rate of continuation of MZB after 12 months was 64.7% in group A and 62.5% in group B, showing that high rates of continuation were maintained. Concomitant therapy of MZB 300 mg twice a week to RA patients who responded poorly to MTX is a useful treatment with minimal adverse effects.