Novel therapies for membranous nephropathy: focus on rituximab

Idiopathic membranous nephropathy (IMN) is the most frequent cause of nephrotic syndrome in adults and may progress to end-stage kidney disease in 30 to 40% of patients over 5 to 15 years. Until recently, the only therapeutic options were based on the use of non-specific immunosuppressants that, however, do not appreciably ameliorate patient and kidney outcome compared to placebo or no treatment. They also have a significant toxicity that may offset the benefits of proteinuria reduction. Thus, more specific and less toxic treatments are needed. Availability of rituximab, a chimeric monoclonal antibody targeting the CD20 antigen on B cells, offered a novel, selective and safer treatment for the disease. Rituximab depletes precursors of aberrant plasma cells, with secondary inhibition of the neoformation of autoantibodies possibly involved in the pathogenesis of the disease. Other treatments have been recently introduced in clinical practice that will hopefully help improve outcomes of the subset of patients with progressive disease.