Levamisole in steroid-sensitive nephrotic syndrome of childhood: the lost paradise?

Among the different drugs used for sparing steroids in steroid-sensitive nephrotic syndrome (SSNS) with frequent relapses and steroid dependency, levamisole is the least toxic and the least expensive. However, it is neither approved for this indication nor widely used in Europe. This may be explained by the difficulty in obtaining levamisole in some countries and the lack of good quality evidence for its effectiveness. Evidence is limited to three clinical trials that all suffered from methodological limitations. Statistical synthesis of these trials showed that levamisole reduces the risk of a relapse during treatment (relative risk 0.60, 95% confidence interval 0.45-0.79). From the available information, no conclusions can be drawn on the steroid-sparing effect, the long-term efficacy, and safety, as well as possible differences in efficacy in different subgroups of SSNS patients. The confirmation of a favorable effect of levamisole on the reduction of the frequency of relapses and on sparing steroids in an adequately powered, double-blind, placebo-controlled, randomized, multi-center clinical trial will promote consensus on the place of levamisole in the treatment of SSNS of childhood. Follow-up should be at least 1 year to evaluate long-term efficacy and side effects. If the results of such a clinical trial confirm the beneficial effects of levamisole in nephrotic syndrome, this may allow registration for this indication and interest companies other than Jansen-Cilag, which only recently has decided to stop its production.