Steroid-sensitive nephrotic syndrome: an evidence-based update of immunosuppressive treatment in children

Nephrotic syndrome is one of the most common paediatric glomerular diseases, with an incidence of around two per 100,000 children per year. Corticosteroids are the mainstay of treatment, with 85%-90% of children going into remission with an 8-week course of treatment. Unfortunately, nephrotic syndrome follows a relapsing and remitting course in the majority, with 90% relapsing at least once. About half will progress to frequently relapsing nephrotic syndrome (FRNS) or steroid-dependent nephrotic syndrome (SDNS). Different initial steroid regimens have been evaluated since the first trials in Europe and America in the 1960s. Most trials have been designed to evaluate the optimal duration of the initial therapy, rather than different cumulative doses of corticosteroid, or the management of relapses. Until recently, these data suggested that an initial treatment duration of up to 6 months reduced the number of children developing a relapse, without evidence of increased steroid toxicity. Recently, three large, well-designed randomised control trials were published, which demonstrated no significant reduction in risk of relapse or of developing FRNS by extended treatment compared with 2 or 3 months. While there are few trial data to guide the treatment of individual relapses in steroid-sensitive nephrotic syndrome (SSNS), there is some evidence that a short course of corticosteroid therapy during upper respiratory tract infection may prevent relapse. In patients with FRNS or SDNS who continue to relapse despite low-dose alternate-day steroids a number of non-corticosteroid, steroid-sparing immunosuppressive agents (cyclophosphamide, ciclosporin, tacrolimus, mycophenolate mofetil, levamisole, rituximab) have been shown to reduce the risk of relapse and of FRNS. However, there are limited head-to-head data to inform which agent should be preferred. In this article, we review recent data from randomised trials to update paediatricians on the current evidence supporting interventions in SSNS.