Practice patterns of rituximab for primary membranous nephropathy 2021 in Japan: a web-based survey of board-certified nephrologists.

BACKGROUND: Although rituximab (RTX) is recommended by kidney disease improving global outcomes as one of the standard therapies for primary membranous nephropathy (pMN), given the constraint of insurance coverage, it is not clear how the drug is used in Japan.

METHODS: This cross-sectional study was conducted via a web-based survey between November and December 2021. The participants were certified nephrologists and recruited through convenience sampling. Experience with RTX for pMN was compared to experience with RTX for minimal change nephrotic syndrome (MCNS). Reasons for withholding RTX for pMN, even when it is indicated, were also investigated. Furthermore, the proportion difference in RTX experience was analyzed.

RESULTS: Responses from 380 nephrologists across 278 facilities were analyzed. RTX was used for pMN by 83 (21.8%), which was less than the 181 (47.6%) who had used RTX for MCNS (ratio of proportions: 0.46). RTX use for pMN was more frequent in facilities performing 41-80 and 81 or more kidney biopsies annually (vs. none) and by physicians with experience in anti-PLA2R antibody measurement. RTX administration for pMN was covered by insurance for 56 (67.5%), was facility-paid for 10 (12.0%), and was copaid by patients for 6 (7.2%). The most common reason for withholding RTX for pMN was difficulty in ensuring financing (146, 79.3%).

CONCLUSIONS: RTX use for pMN is less common than for MCNS but not infrequent. Treatment with RTX was more frequent in biopsy-intensive facilities, and it was fully paid by the facility or patient in one-fifth of cases.