Sutimlimab reduces intravascular and extravascular hemolysis in CAD by inhibiting C1s. CAD results from monoclonal IgM antibodies that target carbohydrate antigens on the surface of red blood cells, leading to complement fixation. Early IgM-induced complement activation can lead to extravascular hemolysis by facilitating macrophage engagement or can lead to intravascular hemolysis by proceeding to terminal complement activation and membrane attack complex (MAC) formation. Sutimlimab inhibits early complement activation by targeting C1s, thereby protecting cells from complement-mediated extravascular and intravascular hemolysis. Professional illustration by Patrick Lane, ScEYEnce Studios.