Current definition of remission in eosinophilic granulomatosis with polyangiitis (EGPA) and future perspectives

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare systemic vasculitis for which achieving remission is the primary therapeutic goal. Historically, remission in EGPA was defined by the absence of active vasculitis, typically a Birmingham Vasculitis Activity Score (BVAS) of 0. However, this definition is insufficient as it overlooks the significant morbidity associated with long-term glucocorticoid (GC) therapy. Recent evidence highlights that even low-dose GCs carry substantial risks, challenging the traditional acceptance of remission on GC. This review summarizes the evolution of the remission concept in EGPA, highlighting the paradigm shift seen in recent pivotal clinical trials for biologics, which have incorporated stringent GC dose thresholds (e.g., prednisone ≤4 mg/day) into their primary endpoints. This reflects a growing consensus that minimizing GC exposure is a crucial component of a successful treatment outcome. Further, this review explores potential future components for remission criteria, such as organ-specific activity measures and patient-reported outcomes.