Con: STOP immunosuppression in IgA nephropathy.

A comprehensive supportive therapy approach constitutes the mainstay treatment of IgA nephropathy (IgAN) patients. In our recent Supportive versus immunosuppressive Therapy Of Progressive IgA Nephropathy (STOP-IgAN) trial, we systematically selected for patients at high risk of a progressive disease course and evaluated the effect of immunosuppression, combined with supportive care, on renal end points in these patients. There was a higher rate of full clinical remission and transient proteinuria reduction in immunosuppressed patients. However, deterioration of renal function (i.e. number of patients with an estimated glomerular filtration rate (eGFR) decrease of at least 15 mL/min over the 3-year trial phase) was remarkably slow in both groups, compared with previous studies, and was not slowed further by adding immunosuppression to supportive care. Here, we address several concerns raised on the design and interpretation of our trial. In our randomized patients, we confirmed a lower baseline proteinuria to be predictive of clinical remission in IgAN. However, the observed transient drop in proteinuria in the immunosuppressed patients did not translate into an improved overall renal outcome in these patients. Although longer follow-up would be desirable, there was not even a trend for the eGFR course to diverge between our two treatment arms during the trial phase. Finally, it is important to note that we excluded specific infrequent patient groups during our run-in phase. Therefore, IgAN patients with a rapidly progressing course and those with persistent proteinuria >3.5 g/day would require further evaluation regarding potential benefits of immunosuppressive therapies.