Targeting CGRP for the Prevention of Migraine and Cluster Headache: A Narrative Review.

Calcitonin-gene-related peptide (CGRP), a neuropeptide broadly distributed in neuronal and non-neuronal regions throughout the body, plays a fundamental role in migraine and cluster headache (CH) pathophysiology. CGRP functional blockade alleviates neurogenic inflammation and reduces pain pathway sensitization. Two types of CGRP function-blocking modalities, monoclonal antibodies (MAbs), and small molecules (gepants), have been designed to target the CGRP ligands and CGRP receptors. In this narrative review, we summarized the latest clinical trials on gepants and CGRP function-blocking MAbs for migraine and CH prevention. At the time of writing, newer gepants are currently under Federal Drug Administration (FDA) review for migraine management, but there is no study yet on the usage of gepants for CH. Erenumab, fremanezumab, and galcanezumab have been approved by the FDA for migraine prevention while eptinezumab is under FDA review. CGRP MAbs are as effective as and more tolerable than conventional migraine preventives. For CH prevention, galcanezumab has shown some promising findings and was recently approved for use in episodic cluster prevention. CGRP function-blocking therapy not only demonstrates high efficacy and superior safety profile, but also improves headache frequency and quality of life. Convenient monthly dosing for the MAbs can further improve medication adherence, hence better headache control. With CGRP function-blocking therapy showing efficacy even in individuals who failed other preventives, it has become an exciting new therapeutic option in the field of migraine and CH.