Nephrotoxicity of once-daily cyclosporine A in minimal change nephrotic syndrome

Although once-daily cyclosporine (CsA) therapy may have greater nephrotoxic-sparing effects than standard twice-daily therapy, little information is available in children with steroid-dependent minimal change nephrotic syndrome (MCNS) regarding histological analysis after long-term once-daily administration. A prospective study of the clinical efficacy and comparison between pre- and post-treatment renal biopsy findings in ten children (mean age, 8.8 years) with steroid-dependent MCNS who were administered once-daily CsA therapy for more than 24 months (mean +/- SD, 30 +/- 3.7) was performed in Saitama Children's Medical Center. Administration of once-daily CsA therapy (mean dose, 2.8 +/- 0.6 mg/kg/day; mean C2 levels, 670 +/- 64 ng/ml) resulted in a significant reduction in the median relapse rate from 4.6 to 0.2 times per year, and five patients did not experience a relapse of NS. Furthermore, mean threshold of prednisolone dose significantly reduced from 1.2 to 0.02 mg/kg on alternate days. However, two patients showed evidence of chronic CsA nephrotoxicity (CsAN). Once-daily CsA therapy appears to be effective in children with steroid-dependent MCNS. However, follow-up renal biopsies should be performed to investigate the presence of CsAN after more than 24 months of treatment with once-daily regimen as well as with the conventional twice-daily regimen.