A Post-Marketing Evaluation of Avacopan Safety with a Focus on Hepatic Adverse Events

Background

Avacopan, an oral complement C5a receptor inhibitor, has been shown to help patients with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) achieve and sustain remission with reduced glucocorticoid exposure and associated toxicity. As of January 20, 2026, estimated global post-marketing exposure exceeded 25,000 patient-years. Hepatic adverse events (AEs), predominantly liver enzyme elevations observed during clinical development, remain an important post approval safety risk. Since approval, vanishing bile duct syndrome (VBDS), a rare but serious complication of drug induced liver injury (DILI) has been reported with avacopan use. This analysis evaluated Amgen's global safety database data to characterize hepatic adverse event reports associated with avacopan, including VBDS.