We report the case of a 54-year-old woman with antineutrophilic cytoplasmic antibody-negative eosinophilic granulomatosis with polyangiitis presenting with mononeuritis multiplex, intestinal hemorrhage, cardiomyopathy, fever, and worsening asthma symptoms. She was initially treated with steroids and cyclophosphamide but eventually required rituximab to control a vasculitis flare. However, her asthmatic symptoms did not improve, despite attaining vasculitis remission. Symptoms abated only after the treatment transition to mepolizumab. After a 1-year interval, there were no further episodes of asthma exacerbation and no requirement for systemic steroid therapy. This report reinforces the use of rituximab for induction and maintenance of remission in patients with eosinophilic granulomatosis with polyangiitis and predominant vasculitic manifestations, whereas mepolizumab demonstrated better control of the persistent eosinophilic manifestations, ensuing sustained remission and improved quality of life.