Obinutuzumab for membranous nephropathy: a systematic review using pooled case-level extraction analysis

Obinutuzumab has increasingly been used in patients with PLA2R-associated membranous nephropathy (MN). However, reported outcomes vary substantially across studies due to heterogeneity in patient selection, response definitions, and follow-up duration. This study aimed to synthesize case-level extraction analysis to better characterize response patterns and factors influencing remission rates. MEDLINE, Web of Science, SCOPUS, and grey literature were systematically searched. Case-level extraction analysis from eligible case reports and case series were synthesized to evaluate clinical and immunological remission. Eighty-nine patients from 19 publications were included. Most patients (64%) were reported from China. During a median follow-up of 12 months, overall clinical and immunological remission rates were 83% and 88.7%, respectively. Complete remission was numerically less frequent in patients refractory to prior immunosuppressive therapy compared with those who had previously responded (23.5% vs. 61.5%; nominal p = 0.012). Clinical remission appeared more common among patients followed for at least 12 months (92.6% vs. 75%; nominal p = 0.026). Geographic variation in reported outcomes was noted and appeared to be influenced by differences in follow-up duration and publication type. Adverse events were inconsistently reported; when reported, they were predominantly mild to moderate. This descriptive case-level extraction analysis is consistent with previous small series reporting relatively high clinical remission rates for obinutuzumab in PLA2R-associated MN. The observed remission rates may be influenced by prior treatment responsiveness and duration of follow-up.