Combined cyclosporine and prednisolone therapy using cyclosporine blood concentration monitoring for adult patients with new-onset minimal change nephrotic syndrome: a single-center pilot randomized trial

Minimal change nephrotic syndrome (MCNS) responds well to steroids, but some patients show frequent relapses. Long-term steroid administration leads to various adverse effects. We previously reported the effectiveness in refractory nephrosis patients of administrating microemulsified CyA (ME-CyA) once before meals and setting the target value of the CyA blood concentration at 2 h after ME-CyA administration (C2) to 600-1200 ng/ml. On this trial we evaluate the effectiveness and safety of ME-CyA for suppressing relapse of adult new-onset MCNS patients using C2 monitoring. Adult new-onset MCNS patients were randomly allocated to a ME-CyA + prednisolone group ("CyA + PSL") (n = 11) and a PSL-alone group ("PSL-alone") (n = 10). The drug administration period was 18 months followed by an observation period of 12 months. The duration of remission tended to be longer in CyA + PSL with C2 > 600 ng/ml than in PSL-alone (P = 0.112). The relapse rate up to 18 months was significantly lower in CyA + PSL with C2 > 600 ng/ml than in PSL-alone (P = 0.02). C2 was significantly higher in the patients with no relapse at 18 months than that in the patients with relapse (P = 0.048). In CyA + PSL, the total dose of PSL was significantly reduced compared with PSL-alone (P = 0.002). Cosmetic adverse effects tended to be fewer in CyA + PSL. The combination treatment regimen of ME-CyA and PSL with C2 > 600 ng/ml has potential to be an important treatment option for adult new-onset MCNS patients. However, after ME-CyA dosage reduction and discontinuation, the relapse rate increased. It is thus necessary to establish a better dose-reduction method.