Impact of the National Institutes of Health Focal Segmental Glomerulosclerosis (NIH FSGS) clinical trial on the treatment of steroid-resistant FSGS

Idiopathic focal segmental glomerulosclerosis (FSGS) is among the most common, morbid and treatment-resistant conditions faced by nephrologists. While glucocorticoids have traditionally been the mainstay of initial treatment, they induce remission in only a minority of patients. A variety of other immunosuppressants have been utilized against steroid-resistant FSGS, but few have been rigorously examined in well-controlled trials. Recently, the results were published from a National Institutes of Health (NIH)-sponsored multicenter randomized trial comparing cyclosporine (CSA) with a combination of mycophenolate mofetil (MMF) and pulse dexamethasone (DEX) for the treatment of steroid-resistant FSGS. No difference in treatment effectiveness was shown between the two groups, and adverse effects were comparable. This was the largest randomized trial ever undertaken in FSGS, but it was unfortunately underpowered to show clinically relevant differences in response rates. This shortcoming, along with particularities of the study population and outcome measures, makes it challenging to draw definitive conclusions from the trial results. Despite these limitations, the trial does provide valuable insights into treatment strategies for FSGS and offers important lessons for planning future research.