<h4>Introduction</h4>Avacopan, a complement 5a receptor (C5aR) antagonist, is a therapeutic option for patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), and is used as a steroid-sparing agent. This evidence concerns the gene C5AR1 and anti-neutrophil cytoplasmic antibody-associated vasculitis.