Safety and efficacy of mizoribine in patients with connective tissue diseases other than rheumatoid arthritis

Effectiveness and safety of Mizoribine for the treatment of IgG4-related Disease: A Retrospective Cohort Study

OBJECTIVE

Patients with IgG4-Related Disease (IgG4RD) usually require steroid-sparing agents due to relapse with tapering glucocorticoids (GC). The aim of this study was to determine the efficacy and safety of Mizoribine (MZR) among IgG4RD, which inhibits inosine monophosphate dehydrogenase, a rate-limiting enzyme in the de novo pathway of purine synthesis.

METHODS

We retrospectively reviewed records of IgG4RD patients at the Immuno-Rheumatology Center in St. Luke's International Hospital, Tokyo, Japan. Patients were classified into the MZR combination group, and those treated with GCs 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 exacerbation.

RESULTS

A total of 14 and 29 cases were included in the MZR combination and control groups, respectively. Multiple organ involvement (≥3 organs) was significantly more frequent in the MZR combination treatment group (10 [71.4%] vs 9 [31.0%], p= 0.021). Kaplan-Meier analysis revealed a significant reduction in exacerbation 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[0.12-1.01] (p= 0.052), and 3.51[1.29-9.51] (p= 0.014). The cumulative GC dose tended to be lower in the MZR combination group (1448[1003, 1642] vs 2179[1264, 3425]; p= 0.09).

CONCLUSION

MZR showed a significant steroid-sparing effect and decrease in exacerbation among IgG4RD patients with multi-organ involvement. MZR could be a treatment option for IgG4RD.

Mizoribine is as Effective as Methotrexate for the Treatment of Polymyalgia Rheumatica: A Retrospective Case Series Analysis

Objectives

This study aims to evaluate the efficacy and safety of mizoribine (MZR) as a steroid-sparing agent compared to methotrexate (MTX) in the treatment of polymyalgia rheumatica in elderly patients.

Patients and methods

Twenty-four patients (9 males, 15 females; mean age 71.7 years; range 50 to 86 years) diagnosed with polymyalgia rheumatica between April 1998 and August 2014, who received prednisone in combination with either MTX or MZR, were included. We collected the data on the cumulative prednisone dose that patients received within 48 weeks after MTX or MZR and its side effect profile.

Results

There were 10 patients in the MTX group and 14 in the MZR group. The cumulative prednisone dose over 0-48 weeks was 2272±396 mg in the MTX group and 1907±241 mg in the MZR group, which was not significantly different (p=0.41). In terms of side effects, in the MTX group, three patients experienced a transient elevation in liver enzymes, and one patient developed gastrointestinal symptoms that led to MTX withdrawal. In the MZR group, one patient was hospitalized due to pneumonia that led to MZR withdrawal.

Conclusion

Mizoribine was non-inferior to MTX in terms of steroid-sparing effects on polymyalgia rheumatica. Also, MZR tended to have fewer side effects than MTX.