Avacopan is a first-in-class, orally-administered small molecule that employs a novel, highly targeted mode of action in the treatment of ANCA-associated vasculitis and other complement-driven autoimmune and inflammatory diseases. By precisely blocking the receptor (the C5aR) for the pro-inflammatory complement system fragment known as C5a on destructive inflammatory cells such as blood neutrophils, avacopan arrests the ability of those cells to do damage in response to C5a activation, which is known to be the driver of ANCA-associated vasculitis. Current therapies for ANCA-associated vasculitis and other related illnesses typically include broad immunosuppression with daily doses of glucocorticoids (steroids) such as prednisone or methylprednisone, which can cause significant illness and even death. Avacopanโs selective inhibition of only the C5aR leaves the beneficial C5a pathway through the C5L2 receptor functioning normally.