Comparison of steroid-pulse therapy and combined with mizoribine in IgA nephropathy: a randomized controlled trial

Background: The significance of immunosuppressants as an adjunct treatment with corticosteroids for IgA nephropathy (IgAN) has not been well demonstrated. This study was performed to compare two treatment regimens, steroid-pulse therapy or combined with mizoribine (MZR) in progressive IgAN. Methods: Study design was a prospective randomized controlled trial of 40 patients with moderate to severe glomerular injuries who were randomly administered either pulse methylprednisolone followed by a 25-month course of oral prednisolone (P group, n = 20) or in combination with MZR (150 mg/day for 24 months, M + P group, n = 20). The primary endpoint was a reduction of proteinuria by ≥50 % of the baseline value. Secondary endpoints were increased serum creatinine (Cr) by ≥50 %, or a decrease in estimated glomerular filtration rate by ≤50 %. Results: Twenty-five months after the initiation of treatment, urinary protein excretion significantly declined from the median of 0.98 to 0.17 g/gCr in the P group (P < 0.05) and from 1.01 to 0.38 g/gCr in the M + P group (P < 0.05). There was no statistical difference in the serial changes of proteinuria between two groups (P = 0.81). All patients reached the primary endpoint, and the cumulative incidence of the reduction of proteinuria was not significantly different (P = 0.76). No patient reached the secondary endpoint during the 25 months of treatment. Conclusions: Both therapeutic regimens significantly reduced the levels of proteinuria. We could not find the additional effect of MZR in combination with steroid-pulses in this small-scale controlled trial. Steroid-pulse therapy with a 25-month course of oral steroids seems to be effective for progressive IgAN.