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JAMA Intern Med 2021; doi: 10.1001/jamainternmed.2021.0366 Received: 23.3.2021; Editorial decision: 9.4.2021 Nephrol Dial Transplant (2021) 36: 1349–1351 doi: 10.1093/ndt/gfab013 Advance Access publication 4 February 2021 Younger children treated with rituximab for nephrotic syndrome are at higher risk of adverse events Camille Laroche 1,2 , Dominique Lemieux 1,3 , Philippe Sylvestre 1 , Anne-Laure Lapeyraque 1,2,4, and Adrien Flahault 1,4, 1 University of Montreal, Montreal, Canada, 2 Department of Pediatrics, Division of Nephrology, Sainte-Justine University Hospital, Montreal, Canada, 3 Department of Pharmacy, Sainte-Justine University Hospital, Montreal, Canada and 4 Sainte-Justine University Hospital Research Center, Montreal, Canada *These authors contributed equally to this work as joint last author.Correspondence to: Anne-Laure Lapeyraque; E-mail: anne- laure.lapeyraque.hsj@ssss.gouv.qc.ca and Adrien Flahault; E-mail: adrien.flahault@umontreal.ca Rituximab is efficient to prevent relapse in pediatric steroid- dependent nephrotic syndrome (SDNS). Although rituximab tolerance is usually reported as good in clinical trials [1–7], the rate of severe adverse events (SAEs) differs considerably be- tween studies, ranging from 3% to 33%, suggesting disparities in SAE reporting. One study has shown that the median age of patients presenting with agranulocytosis after rituximab treat- ment for nephrotic syndrome (NS) was younger than those who did not [8]. In this single-center retrospective study, we aimed to determine risk factors associated with occurrence of adverse events following rituximab in children with SDNS. Detailed methods are provided in the Supplementary file. Briefly, we retrospectively reviewed the charts of all patients aged <18years who had received rituximab for SDNS between November 2007 and September 2019 in our institution. Patients were seen in the Nephrology clinic at least once a month after their treatment. Our main objective was to assess rituximab safety in our cohort. Information on SAEs [Grade 3, severe but not immediately life-threatening; Grade 4, life- threatening; and Grade 5, death, according to the Common Terminology Criteria for Adverse Events (CTCAE)] [9] was collected in patients’ charts. We performed a survival analysis to assess risk factors associated with SAEs and relapses. V C The Author(s) 2021. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved. 1349 RESEARCH LETTER Downloaded from https://academic.oup.com/ndt/article/36/7/1349/6128516 by guest on 23 September 2022