Back to the Future: Therapies for Idiopathic Nephrotic Syndrome

Background: Roughly 20-40% of individuals with idiopathic nephrotic syndrome will fail to respond to standard therapies and have a high risk of progression to end stage kidney disease (ESKD). In the last 50 years, no new therapies have been approved specifically for the treatment of these individuals with recalcitrant disease. Summary: Recent in vitro, translational, and clinical studies have identified novel targets and pathways that not only expand our understanding of the complex pathophysiology of proteinuric disease but also provide an opportunity to challenge the tradition of relying on histologic classification of nephrotic diseases to make treatment decisions. Key Messages: The traditional methods of directing the care of individuals with nephrotic syndrome by histological classification or deciding second line therapies on the basis of steroid-responsiveness may soon yield customizing therapies based on our expanding understanding of molecular targets. Important non-immunologic mechanisms of widely used immunosuppressive therapies may be just as important in palliating proteinuric disease as proposed immunologic functions.