TWO CASES OF MPO-ANCA-POSITIVE EGPA WITH CHRONIC RHINOSINUSITIS SHOWING DIFFERENT RESPONSES TO MEPOLIZUMAB

Abstract

Eosinophilic granulomatosis with polyangiitis (EGPA) is a systemic vasculitis associated with chronic rhinosinusitis (CRS) and bronchial asthma. Mepolizumab, an anti-IL-5 monoclonal antibody, has been used in the treatment of EGPA. We report two cases of MPO-ANCA-positive EGPA with CRS that exhibited differing responses to mepolizumab. In Case 1, nasal symptoms persisted despite mepolizumab treatment, and CRS recurred early after endoscopic sinus surgery (ESS). In contrast, Case 2 developed EGPA following dupilumab administration, but nasal symptoms improved with mepolizumab and remained well controlled. These cases suggest that the efficacy of mepolizumab for CRS in ANCA-positive EGPA varies among patients. Even in cases that respond well to treatment, recurrence may still occur, underscoring the importance of continuous follow-up in close collaboration with internal medicine specialists.