Effect of Immunosuppression in IgA Nephropathy

IgA nephropathy (IgAN) is the most common glomerulonephritis worldwide, leading to end stage renal disease (ESRD) in up to 30 to 40% of patients with in a few decades after diagnosis. Several therapeutic options have been used in clinical practice. However, no treatments can completely stop the progression of IgAN. Given the pathogenic mechanism of IgAN, many researchers have tried to treat patients with IgAN using immunosuppression such as corticosteroids. To date, there have been conflicting results on the effects of immunosuppression in IgAN. Earlier studies from Italian groups showed that corticosteroid treatment significantly attenuated kidney function decline and decreased the development of ESRD. Since then, the beneficial effects of corticosteroids have generally been accepted for treatment of IgAN particularly in patients with high degree of proteinuria \> 1.0 g/day despite maximal conservative care during 3 to 6 months. However, a recent interventional study by German group, known as the Supportive Versus Immunosuppressive Therapy for the Treatment of Progressive IgA Nephropathy (STOP-IgAN) trial, showed that immunosuppressive treatment in addition to intensive supportive care did not significantly improve renal outcome and resulted in more treatment-related side effects. Moreover, the Therapeutic Evaluation of Steroids in IgA Nephropathy Global (TESTING) study, another randomized controlled study from China, was early terminated because of safety concern related to corticosteroids. Interestingly, the primary composite outcome occurred significantly less in the methylprednisolone group as compared to the placebo group despite more serious adverse events in the former group. With this background in mind, we designed a multicenter prospective randomized controlled open-label trial; a step-wise therapeutic approach with corticosteroids or add-on cyclophosphamide therapy in IgAN patients with persistent proteinuria who have preserved eGFR of ≥ 30 ml/min/1.73 m