Efficacy and safety of low-dose rituximab as induction therapy for antineutrophil cytoplasmic antibody-associated vasculitis with renal involvement: a Chinese case series

Background Rituximab (RTX) is a standard therapy for antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). However, the most frequently used dose may lead to severe adverse effects (SAEs). We explored the efficacy and safety of low-dose RTX in Chinese patients with AAV. Methods A total of 22 Chinese patients diagnosed with AAV with renal involvement, including 8 treated with low-dose RTX (400 mg of RTX total over 4 weeks) and 14 treated with cyclophosphamide (CYC), were evaluated. The baseline clinical and pathological data and laboratory parameters during follow-up at months 1, 3, 6, and 12 were collected retrospectively. Results The baseline data showed no significant differences between the two groups. The median peripheral CD19 + cell counts in the RTX group decreased from 315.0/μL to 1.5/μL at 2 weeks, and to 2.5/μL at 1 month after the first dose. The median SCr level decreased from 267.8 μmol/L before treatment to 151.45 μmol/L at 1 month, 132.75 μmol/L at 3 months, 123.2 μmol/L at 6 months, and 151.9 μmol/L at 12 months in RTX-treated patients. The improvements in renal function, proteinuria, and ANCA titre were not significantly different between the two groups. The SAE rate was significantly lower in the RTX group (one SAE of pneumonia) compared with the CYC group. Conclusions This is the first report that low-dose RTX could be effective for the treatment of Chinese patients with AAV with renal involvement.