New Therapies for the Treatment of Idiopathic Nephrotic Syndrome

Abstract

The treatment of children with idiopathic nephrotic syndrome who have multiple relapses or who are steroid-resistant is a difficult issue. Alkylating agents are often proposed but they have several side effects, including gonadal toxicity, which limit their use. Treatment with levamisole may be efficient in steroid-dependent patients, allowing prednisone to be tapered or stopped in approximately 50% of cases. Cyclosporine has proved to be effective in 85% of steroid-dependent patients, but most patients relapse when cyclosporine is tapered or withdrawn. Thus, in these patients, cyclosporine may be required for long periods of time. Conversely, cyclosporine alone is less effective in steroid-resistant patients, as only 28% of these patients respond to the treatment. Cyclosporine in association with prednisone may be a better alternative as, in our experience, 14 out of 31 patients went into remission with such treatment. It should be stressed that response to cyclosporine is better correlated with initial steroid responsiveness than with histological category. Eighteen out of 43 patients with serial renal biopsies developed significant tubulo interstitial lesions which could be attributable to cyclosporine nephrotoxicity. The risk of developing chronic nephrotoxicity appears to be higher in steroid-resistant patients. Cyclosporine nephrotoxicity is not related to the duration of treatment and may develop in patients with normal renal function.