To evaluate the efficacy and safety of low-dose rituximab (LD-RTX) for remission induction in patients with ANCA-associated vasculitis (AAV).

Patients with AAV who received RTX between 2006 and 2025 at Chinese PLA General Hospital were retrospectively reviewed. Low-dose RTX was defined as either 500mg or 375mg/m² administered at day 0 and 14, while all other RTX regimens were categorized as non-standard doses. Baseline demographic, clinical, and laboratory data were collected. The primary outcome was remission at 6 months, defined as a BVAS of 0. Secondary outcomes included remission at 3 months, changes in ANCA levels, peripheral B-cell counts, and adverse events during follow-up.

A total of 87 patients were included. Baseline demographic, clinical, and laboratory characteristics were comparable between the two groups. Remission rates at 3 and 6 months were significantly higher in the LD-RTX group than in the NS-RTX group (32/43, 74.4% vs 4/40, 10.0% and 38/43, 88.4% vs 7/40, 17.5%, respectively; both P < 0.001). Median ANCA titre decreased from 200.0 at baseline to negative by 6 months in the LD-RTX group, whereas it remained detectable at 37.5 in the NS-RTX group. Median B-cell level decreased from 0.73% to 0.01% in the LD-RTX group. Adverse events occurred in 13.6% of patients in the LD-RTX group and 23.8% in the NS-RTX group (P = 0.274).

LD-RTX regimen is more effective than NS-RTX regimen for remission induction in AAV and no significant increase in adverse events.