Study of mizoribine therapy in elderly patients with membranous nephropathy: comparison with patients not receiving mizoribine.

We have previously reported the results of mizoribine (MZR) treatment for elderly patients with membranous nephropathy (MN). Here, we retrospectively compared these patients with those who had been initially treated with prednisolone (PSL) alone. The subjects were patients with MN aged ≥65 years who were examined between April 2007 and September 2010 and followed for at least 1 year. The median period until the start of treatment in the MZR group (MZR-G) was 60 days. The urinary protein level at the start of MZR treatment was 3.89±2.3 g/gCr. Urinary protein in the group not treated with MZR (N-MZR-G) was 1.0±1.1 g/gCr, showing a tendency to improve in patients with nephrotic syndrome relative to the MZR-G (p=0.055). The PSL dose in the MZR-G versus N-MZR-G at 1 year was 5.7±3.0 versus 6.25±2.5 mg/day, the urinary protein level was 0.19±0.2 versus 0.13±0.1 g/gCr, and the remission rate was 80 versus 75%. In the MZR-G, the total PSL dose at 1 year after the start of MZR treatment was 5,058±1,904 versus 6,649±875 mg in the N-MZR-G. Adverse events occurred in 3/5 patients (60%) in the MZR-G and in 3/4 patients (75%) in the N-MZR-G. Elderly patients with MN who respond poorly to PSL treatment may be treated successfully with MZR.