Effectiveness and safety of rituximab for remission maintenance therapy in microscopic polyangiitis and granulomatosis with polyangiitis in Japan: A retrospective multicentre cohort study (J-CANVAS).

OBJECTIVES

Rituximab (RTX) is a standard maintenance therapy for antineutrophil cytoplasmic antibody-associated vasculitis. Its efficacy in Japan remains unclear, where microscopic polyangiitis (MPA) predominates and clinical characteristics differ from Western-dominated randomized controlled trial (RCT) populations.

METHODS

Japanese patients with MPA or granulomatosis with polyangiitis (GPA) enrolled in a nationwide registry were included. Exposure was RTX use during maintenance therapy. The primary endpoint was major relapse-free survival at 104 weeks. The secondary endpoint was any relapse-free survival (major or minor) at 104 weeks. Baseline differences were adjusted using inverse probability of treatment weighting based on key demographic and disease-related covariates.

RESULTS

A total of 389 patients were analysed, with 85 in the RTX group. The RTX group included a higher proportion of GPA cases (37/85 vs. 74/304), resulting in baseline imbalance. After inverse probability of treatment weighting, no major relapses were observed in the RTX group, whereas the major relapse-free survival at 104 weeks was 94.8% in the non-RTX group. The RTX group showed significantly higher any relapse-free survival at 104 weeks (95.4% versus 83.3%; HR for any relapse, 0.27; 95% CI, 0.09-0.74; P = .02).

CONCLUSIONS

Our findings suggest that RTX may be an effective option for remission maintenance in Japanese patients with MPA or GPA.