Myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA)-positive vasculitis frequently affects the kidney and the lung, with alveolar hemorrhage being fatal. Whereas aggressive immunosuppressive therapies are conventionally used, recent studies have shown the beneficial effect of avacopan, a C5a antagonist, as an alternative to glucocorticoids for ANCA-associated vasculitis (AAV). In patients with pulmonary hemorrhage and severe respiratory failure, however, neither the efficacy of avacopan nor the contribution of this drug to early withdrawal of glucocorticoids is fully qualified. Here, we report a case of AAV presenting with alveolar hemorrhage requiring aggressive ventilatory support in which we experienced the favorable effect of early use of avacopan. A 31-year-old man was referred to our hospital because of a two-week history of blood sputum and positive MPO-ANCA. His respiratory failure deteriorated rapidly, necessitating both mechanical ventilation and extracorporeal membrane oxygenation. A combination therapy with glucocorticoids and rituximab was initiated and avacopan was started on hospital day 8, which resulted in successful remission within six months of admission (Birmingham Vasculitis Activity Score version 3 = 0), and the beneficial effect was sustained for at least 6 months following the discontinuation of glucocorticoid withdrawal (day 156). Thus, avacopan, in combination with immunosuppressives, may not only help suppress the disease activity of AAV but also facilitate early withdrawal of glucocorticoids even in case of life-threatening respiratory failure.
Keywords: ANCA-associated vasculitis; Avacopan; Extracorporeal membrane oxygenation; Microscopic polyangiitis; Prednisolone; Pulmonary hemorrhage.
© 2026. The Author(s).