MPO-ANCA-positive eosinophilic granulomatosis with polyangiitis complicated by alveolar haemorrhage treated with mepolizumab as an induction therapy: Case report.

Eosinophilic granulomatosis with polyangiitis (EGPA) is a systemic vasculitis preceded by bronchial asthma or allergic sinusitis and accompanied by peripheral blood eosinophilia. Immunosuppressive drugs, such as cyclophosphamide in addition to high-dose glucocorticoids (GCs), are recommended for induction of remission in patients with severe EGPA. Although mepolizumab is widely recognised as remission induction therapy in nonfatal/nonorgan disabling or relapsed/refractory EGPA, its efficacy and safety in induction of remission for severe cases have been ambiguous. In this context, we report a case of myeloperoxidase antineutrophil cytoplasmic antibody-positive severe EGPA in which the patient had a favourable course using mepolizumab as an induction remission therapy. The patient, a 74-year-old man, had myeloperoxidase antineutrophil cytoplasmic antibody-positive severe EGPA with alveolar haemorrhage. High-dose GCs and intravenous cyclophosphamide were started as remission induction therapy. However, after the initiation of intravenous cyclophosphamide, alveolar haemorrhage worsened, and there was development of opportunistic infections, such as aspergillus and cytomegalovirus antigenaemia. Treatment with the antifungal drug voriconazole and the antiviral drug ganciclovir was started for opportunistic infection, and the treatment for EGPA was switched from intravenous cyclophosphamide to mepolizumab. As a result, alveolar haemorrhage improved, GCs were reduced, and the infection also improved. Mepolizumab as remission induction therapy for severe EGPA were thought to be appropriate and effective treatment in this case. However, the efficacy and safety of mepolizumab for this purpose require comprehensive evaluation.