Rituximab for Adults With Multi-Drug Resistant Focal Segmental Glomerulosclerosis: A Case Series and Review of the Literature

BACKGROUND: Adults with primary focal segmental glomerulosclerosis (FSGS) are frequently resistant to multiple immunosuppressive agents, which is associated with ongoing complications of nephrotic syndrome and a high risk of progression to end-stage renal disease (ESRD). Rituximab, a monoclonal antibody against the B cell CD20 antigen, has shown some preliminary evidence in treating nephrotic syndrome. OBJECTIVES: Describe the usage and the efficacy of rituximab for adults with FSGS in British Columbia (BC) (Canada) and perform a literature review of multi-immunosuppressive drug resistant FSGS in adult patients treated with rituximab to estimate the overall response rate. DESIGN: Case series report and a literature review. PATIENTS: For the case-series, all BC patients who received rituximab for a diagnosis of primary FSGS were included. The literature review included all cases of immunosuppressive-resistant FSGS patients treated with rituximab. We excluded transplant and pediatric patients in both groups. METHODS: We describe all cases of adults with native-kidney FSGS resistant to conventional immunosuppressive medications from our provincial health database who were treated with rituximab from 2014 to 2018. A review of the existing literature was performed via PubMed, MEDLINE, and Embase using the following keywords: rituximab, focal segmental glomerulosclerosis, and FSGS up to August 2019. RESULTS: We characterize four immunosuppressive-resistant FSGS patients who were treated with rituximab as part of our provincial program, all of whom showed a response to rituximab with a sustained remission. We found 29 specific cases in the literature of adults with native-kidney FSGS treated with rituximab after being resistant to other immunosuppressive medications, of whom 15 cases showed a response to rituximab. This has increased the total response rate from 15/29 (52%) to 19/33 (58%). LIMITATIONS: Literature on this topic is coming predominantly from case series. Prospective trials are needed to confirm efficacy, tolerability, and duration of remission. CONCLUSIONS: Due to the low number of currently reported cases and variable response rates, these four cases provide critical data to generate a more accurate understanding of the role of rituximab in adults with resistant FSGS. Adding these results to the confirmed literature cases of multiple-immunosuppressive-resistant FSGS patients treated with rituximab results in a total remission rate of 19/33 cases.