Definition

An orally bioavailable inhibitor of complement factor D (FD; CFD), a serine protease that cleaves complement factor B, with potential complement system inhibiting activity. Upon administration, vemircopan targets, binds to and blocks the activity of FD, and thereby inhibits cleavage of complement factor B into Ba and Bb in the alternative pathway of the complement cascade. This inhibits FD-mediated signaling and activation of the alternative complement pathway (ACP), blocks complement-mediated hemolysis in paroxysmal nocturnal hemoglobinuria (PNH) and prevents ACP-induced tissue damage. FD plays a key role in the activation of the ACP.