The PAC1 receptor is a G-protein-coupled receptor that binds with high affinity to pituitary adenylate cyclase-activating polypeptide (PACAP). This ligand-receptor pair is a key mediator in the transmission of pain signals and the pathophysiology of migraine, involved in trigeminovascular activation, neurogenic inflammation, and vasodilation. By antagonizing PAC1, zelminemab is designed to inhibit this pathway and prevent the onset of migraine.