Objective: Patients with IgG4-related disease (IgG4RD) usually require steroid-sparing agents due to relapse with tapering glucocorticoids (GC). We aimed to determine the efficacy and safety of mizoribine (MZR) among IgG4RD patients.
Methods: We retrospectively reviewed records of IgG4RD patients at Immuno-Rheumatology Center in St. Luke's International Hospital, Tokyo, Japan. Patients treated with MZR were classified into the MZR group, and those treated with GC alone or with other immunosuppressants were included in the control group. Disease exacerbation, GC dose, IgG-IgG4 titre and adverse events were evaluated using univariate analyses, including the Kaplan-Meier method. The Cox proportional hazard model was used to evaluate risk factors for disease exacerbation.
Results: A total of 14 and 29 cases were included in the MZR and control group. Multiple organ involvement (three or more organs) was significantly more frequent in the MZR group [10 (71.4%) vs 9 (31.0%), P= 0.021]. Kaplan-Meier analysis revealed a significant reduction inexacerbation in patients with multiple organ involvement (P< 0.001) but not in total (P= 0.42). The adjusted hazard ratios of MZR use and multiple organ involvement for exacerbation were 0.34 (95%CI 0.12-1.01; P = 0.052) and 3.51 (95%CI 1.29-9.51; P= 0.014). The cumulative GC dose (mg per year, interquartile range) tended to be lower in the MZR group [1448 (1003-1642) vs 2179 (1264-3425); P= 0.09].
Conclusion: MZR decreased disease exacerbation among IgG4RD patients with multi-organ involvement and showed a steroid-sparing effect. MZR could be a treatment option for IgG4RD.
Keywords: IgG4-related disease; glucocorticoid; immunosuppressants; mizoribine.
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