What are the recommended first-line treatment options for a patient diagnosed with Microscopic Polyangiitis (MPA)?

For patients diagnosed with Microscopic Polyangiitis (MPA), which is a type of antineutrophil cytoplasmic antibody-associated vasculitis (AAV), the recommended first-line treatment typically involves an induction therapy regimen aimed at achieving remission (Chung et al., 2021; Ahn and Lee, 2023). This induction therapy primarily consists of high-dose glucocorticoids combined with either rituximab or cyclophosphamide (Chung et al., 2021; Ahn and Lee, 2023). The choice between rituximab and cyclophosphamide often depends on factors such as disease severity, patient characteristics, and previous treatment history (Chung et al., 2021). Rituximab is generally preferred for patients with relapsing disease or those for whom cyclophosphamide is contraindicated (Chung et al., 2021). Cyclophosphamide is a highly effective option, particularly for severe, organ-threatening manifestations of the disease (Chung et al., 2021). In cases of severe kidney disease or diffuse alveolar hemorrhage, plasma exchange may also be considered as an adjunctive therapy during the induction phase (Chung et al., 2021).