Avacopan is used as a targeted therapy in the treatment of autoimmune diseases, particularly anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis. It functions by selectively inhibiting the C5a receptor, a key component in the complement system that drives inflammation. By blocking this pathway, avacopan reduces the activation and migration of inflammatory cells, especially neutrophils, thereby limiting tissue damage in small blood vessels. Its primary application is as an adjunct to standard immunosuppressive therapy, allowing for reduced doses of glucocorticoids like prednisone, which are associated with significant side effects. This steroid-sparing effect improves patient outcomes by maintaining efficacy while minimizing long-term complications such as diabetes, osteoporosis, and cardiovascular issues. Avacopan has shown clinical benefit in inducing and maintaining remission in patients with severe forms of vasculitis, offering a more targeted and tolerable treatment approach. It is taken orally, which supports outpatient management and long-term adherence. Ongoing research is exploring its potential in other complement-mediated inflammatory conditions.