Use of avacopan in granulomatosis with polyangiitis with predominant gastrointestinal and kidney involvement.

Avacopan, an oral C5a receptor 1 antagonist, is approved as a glucocorticoid-sparing option for remission induction in antineutrophil cytoplasmic antibody-associated vasculitis. Since April 2026, its marketing authorisation is undergoing regulatory review by the US Food and Drug Administration and the European Medicines Agency. We report the case of a middle-aged man with granulomatosis with polyangiitis (GPA) presenting with severe gastrointestinal involvement complicated by recurrent bleeding and bowel perforations together with rapidly progressive glomerulonephritis. Despite rituximab and high-dose glucocorticoids, disease activity progressed. Avacopan was introduced as adjunctive therapy during critical illness. Its initiation was temporally associated with multi-organ recovery and enabled rapid corticosteroid withdrawal, with no evidence of hepatotoxicity. This case illustrates real-world use of avacopan in a severe multisystem GPA phenotype with gastrointestinal involvement and adds to the accumulating post-marketing clinical experience being evaluated in ongoing regulatory assessments of this agent.