Molecular Pathogenesis and Targeted Therapies in Eosinophilic Granulomatosis with Polyangiitis: An Updated Review

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare systemic vasculitis characterized by asthma, eosinophilia, and necrotizing inflammation of small- to medium-sized vessels. Accumulating evidence indicates that EGPA is a polygenic and heterogeneous disorder comprising distinct antineutrophil cytoplasmic antibody (ANCA)-defined endotypes with divergent genetic backgrounds, immune pathways, and clinical phenotypes. Its pathogenesis reflects the convergence of epithelial-alarmin signaling, type 2 inflammation, eosinophil effector mechanisms, and B-cell/autoantibody responses, with myeloperoxidase (MPO)-ANCA serving as a hallmark of the vasculitic subset. Recent advances in genomics, immunology, and multi-omics profiling have uncovered biomarkers and molecular circuits sustaining disease activity and guiding therapeutic stratification. The identification of the interleukin (IL)-5-eosinophil axis, epithelial-derived alarmins, and B-cell/IgG4 networks as central pathogenic nodes has enabled the development of targeted biologic therapies that are redefining treatment paradigms. Benralizumab (anti-IL-5Rα) has recently been approved for EGPA following the phase 3 head-to-head MANDARA trial, which demonstrated non-inferiority to mepolizumab in achieving remission (BVAS = 0 with ≤4 mg/day prednisone equivalent) at weeks 36 and 48. These results, together with the established efficacy of mepolizumab, inform practical selection between IL-5 and IL-5Rα blockade and support glucocorticoid-sparing approaches. A structured literature search (2015-2025) was conducted in PubMed, Scopus, and Web of Science to identify recent advances in epidemiology, genetics, biomarkers, and targeted therapies for EGPA. This updated review integrates molecular insights, clinical endotypes, and therapeutic innovations to outline current evidence and future precision-medicine strategies aimed at improving long-term patient outcomes.