Remission Induction Therapy with Rituximab for Microscopic Polyangiitis: A Feasibility Study

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/m 2 /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/m 2 ). 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.

The Efficacy and Safety of Rituximab in ANCA-Associated Vasculitis: A Systematic Review

“…Moreover, another study investigated low-dose RTX therapy as an induction regimen and showed that low-dose RTX therapy was effective in refractory AAV patients, which has a beneficial effect because of the expensive price [ 87 ]. Satio et al [ 88 ] investigated a single dose of 375 mg/m 2 and confirmed that a single dose of RTX is effective in MPA and was associated with decreasing economical damage. However, Moog et al [ 89 ] showed that a single dose of RTX combined with other immunosuppressive therapies is not as effective as a licensed RTX therapy regimen.…”

Improvement of Alveolar Hemorrhaging in an Elderly and Renally Impaired Patient with Relapsing Anti-neutrophil Cytoplasmic Autoantibody-associated Vasculitis by Single Infusion of Rituximab

“…For the induction of remission of AAV, it is common to administer RTX at a dose of 375 mg/m 2 every week for 4 consecutive weeks or 1,000 mg twice every 2 weeks ( 6 ). Regarding the number of administrations and dosage of RTX, single infusion of RTX was effective not only at a dose of 375 mg/m 2 but also at a dose of 500 mg/body for remission induction of AAV ( 4 , 7 ).…”

“…The efficacy of RTX at 500 mg, the dosage that was decided in order to reduce the risk of infections, was investigated and compared with that of azathioprine as maintenance treatment of AAV patients; RTX showed a better outcome than azathioprine ( 8 ). The risk of infection with RTX may be lower with a single infusion of RTX than at the normal dose ( 7 , 9 ). In our case, B-cell depletion was achieved with a single dose of RTX at 500 mg and was maintained for six months.…”

Mast cells and primary systemic vasculitides

“…Rituximab has shown positive results for people with certain types of vasculitides, including microscopic polyangiitis and Wegener's granulomatosis . Rituximab is a synthetic antibody that selectively reduces the number of B cells circulating in the blood, and it helps to decrease inflammation without the use of steroids.…”

“…Wegener's granulomatosis. 81,82 Rituximab is a synthetic antibody that selectively reduces the number of B cells circulating in the blood, and it helps to decrease inflammation without the use of steroids. A humanized anti-human IL-6 receptor antibody tocilizumab has been successfully used and in eight cases of refractory large-vessel vasculitis and CGA.…”