Avacopan is primarily used in the treatment of autoimmune diseases, particularly anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis. It works by selectively inhibiting the complement C5a receptor, which plays a key role in the inflammatory response. By blocking this receptor, avacopan helps reduce inflammation and tissue damage caused by the immune system's overactivity. This makes it a valuable therapeutic option for managing severe cases of vasculitis, often in combination with other immunosuppressive therapies. Its targeted mechanism of action offers a more precise approach to controlling inflammation while potentially minimizing broader immune suppression.