Treatment of migraine is on the cusp of a new era with the development of drugs 
that target the trigeminal sensory neuropeptide calcitonin gene-related peptide 
(CGRP) or its receptor. Several of these drugs are expected to receive approval 
for use in migraine headache in 2018 and 2019. CGRP-related therapies offer 
considerable improvements over existing drugs as they are the first to be 
designed specifically to act on the trigeminal pain system, they are more 
specific and they seem to have few or no adverse effects. CGRP receptor 
antagonists such as ubrogepant are effective for acute relief of migraine 
headache, whereas monoclonal antibodies against CGRP (eptinezumab, fremanezumab 
and galcanezumab) or the CGRP receptor (erenumab) effectively prevent migraine 
attacks. As these drugs come into clinical use, we provide an overview of 
knowledge that has led to successful development of these drugs. We describe the 
biology of CGRP signalling, summarize key clinical evidence for the role of CGRP 
in migraine headache, including the efficacy of CGRP-targeted treatment, and 
synthesize what is known about the role of CGRP in the trigeminovascular system. 
Finally, we consider how the latest findings provide new insight into the 
central role of the trigeminal ganglion in the pathophysiology of migraine.