Background: Cyclosporine A (CyA) has been shown to be effective in membranous nephropathy (MN). However, the optimal dose and the duration of treatment remain controversial issues. We evaluated the efficacy of low-dose CyA alone or combined with corticosteroids as induction and long-term treatment for nephrotic patients with MN.
Methods: In the first part of the study, 51 nephrotic patients with MN were treated either with CyA and prednisolone (n=31) or CyA alone (n=20) for 12 months. Patients who responded with complete remission (CR) or partial remission (PR) were placed on long-term treatment with lower doses of CyA and prednisolone or CyA alone. The mean follow-up of the second part of the study was 26+/-16 months and 18+/-7 months, respectively.
Results: After 12 months of treatment, 26 patients in the combination group and 17 patients in the monotherapy group had a CR or PR of proteinuria (P=NS). Renal function was unchanged in the two groups. During long-term treatment relapses were more frequent in the monotherapy group (47 vs 15%, P<0.05). Daily CyA dose was higher in non-relapsers in both groups (combination 1.4+/-0.5 vs 1.0+/-0.3 mg/kg, P<0.001, monotherapy 1.5+/-0.4 vs 1.1+/-0.2 mg/kg, P<0.003). Relapsers in both groups had lower CyA trough levels (72+/-48 ng/ml) compared with non-relapsers (194+/-80 ng/ml) (P<0.03). Renal function and proteinuria remained stable during the follow-up.
Conclusion: This study suggests that 12-month therapy with CyA (+/-prednisolone) is effective in inducing remission in most nephrotic patients with MN and well-preserved renal function. Longer treatment with lower doses is a useful approach to maintain remission. Relapses occur more frequently in the monotherapy group and usually are associated with CyA trough levels<100 ng/ml.