IgA Nephropathy: A European Perspective in the Corticosteroid Treatment

Abstract

Background: IgA nephropathy (IgAN) is detected in Europe in 22% of glomerular diseases diagnosed by biopsy. The frequency of IgAN as cause of ESRD in Europe has increased in the last decades, accounting for 35% of young and adult transplanted patients. These data justify the interest for risk factors and a possible therapeutic approach. Summary: Insight into a European perspective of IgAN was allowed by the multicenter study VALIGA, on 1,147 patients, almost all Caucasians, with follow-up of 4.7 years. The predictive value of mesangial hypercellularity (M), segmental sclerosis (S), tubular atrophy interstitial fibrosis (T) as independent biomarkers of progression was validated. Endocapillary hypercellularity was predictive of increased follow-up proteinuria. Two groups of patients selected by a propensity score to perfectly match for histologic features (MEST) and clinical data treated with renin-angiotensin system blockers (RASBs) and corticosteroids, or RASBs alone were compared and a beneficial effect of corticosteroids in addition to RASB was found in patients with proteinuria > 1 g/day, with an initial eGFR < 50 mL/min/1.73 m². On the contrary, the STOP-IgAN RCT found that immunosuppressive therapy in addition to optimal supportive care did not provide substantial kidney-related benefits in European patients with IgAN, because there was no difference in the rate of decrease in eGFR, although corticosteroid/immunosuppressive therapy induced complete remission of proteinuria more frequently than supportive care alone. The NEFIGAN trial evaluated a targeted release formulation of budesonide (TRF budesonide) delivering the drug in the distal ileum. TRF budesonide, additionally to optimized RAS blockade, reduced proteinuria and maintained eGFR in IgAN patients, suggesting a reduced risk of future progression to ESRD. Key Messages: In Europe, there is a reasoned search of a balanced approach to corticosteroid therapy for patients with IgAN, with particular attention to selecting the patients at risk of progression while limiting the unwanted systemic adverse events.