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Remission Induction Therapy with Rituximab for Microscopic Polyangiitis: A Feasibility Study
Ayako Saito1, Yoichi Takeuchi1, Saeko Kagaya1
1Department of Nephrology, Japanese Red Cross Ishinomaki Hospital.
Abstract:
Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is systemic vascular inflammation. Microscopic polyangiitis (MPA) is a major type of AAV in Japan. MPA often affects the kidneys and lungs, leading to death if untreated. Induction therapy (i.e., initial treatment) for MPA has not been optimized, although methylprednisolone and cyclophosphamide are commonly used. Recently, rituximab (RTX) (a monoclonal antibody against the protein CD20) has also been used to treat refractory AAV. RTX at 375 mg/m2/week for 4 weeks (i.e., the conventional lymphoma dosing schedule) is used, but the optimal dosing schedule is controversial. Indeed, a single-dose of RTX successfully controlled nephrotic syndrome. However, to date, the effectiveness of a single RTX dose in treating MPA has not been fully investigated in Japan. This was a retrospective observational study. Six newly diagnosed patients with MPA were initially treated with methylprednisolone and a single dose of RTX (375 mg/m2). We investigated the patients' clinical features, as well as the efficacy and safety of RTX treatment. All patients attained remission on a tapered prednisolone dose of < 10 mg/day during the first 12 months. One patient relapsed after 12 months whereas another required hospitalization owing to infective spondyloarthritis. Adverse reactions to RTX infusion and late-onset neutropenia were not observed. Therefore, a single-dose treatment with RTX induced remission with few complications, and allowed tapering the prednisolone treatment. We conclude that a single dose of RTX is a promising induction therapy for MPA, reducing the cost associated with multiple doses.
Insights
A single dose of rituximab (RTX) effectively induced remission in microscopic polyangiitis (MPA) patients in Japan, allowing for reduced prednisolone use and fewer complications. This approach shows promise for MPA induction therapy.
Area of Science:
- Nephrology
- Rheumatology
- Immunology
Background:
- Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) encompasses systemic vascular inflammation, with microscopic polyangiitis (MPA) being a prevalent subtype in Japan.
- MPA commonly impacts the kidneys and lungs, posing a significant mortality risk if left untreated.
- Current induction therapy for MPA, often involving methylprednisolone and cyclophosphamide, requires optimization, and the role of rituximab (RTX) in MPA treatment, particularly dosing, remains debated.
Observation:
- This retrospective study evaluated six newly diagnosed MPA patients in Japan treated with methylprednisolone and a single 375 mg/m² dose of RTX.
- Clinical features, efficacy, and safety of this RTX regimen were assessed.
- The study focused on the effectiveness of a single RTX dose, a regimen not extensively studied in Japan for MPA.
Findings:
- All six patients achieved remission within 12 months, with a tapered prednisolone dose below 10 mg/day.
- One patient experienced relapse after 12 months, and another was hospitalized for infective spondyloarthritis.
- No adverse reactions to RTX infusion or late-onset neutropenia were observed, indicating a favorable safety profile.
Implications:
- A single RTX dose demonstrates potential as an effective induction therapy for MPA, facilitating prednisolone dose reduction.
- This regimen offers a promising, potentially cost-effective alternative to multi-dose RTX protocols.
- Further investigation into single-dose RTX for MPA induction therapy is warranted, especially in the Japanese population.
