Migraine is a highly disabling neurological pain disorder in which management is frequently problematic. Most abortive and preventative treatments employed are classically non-specific, and their efficacy and safety and tolerability are often unsatisfactory. Mechanism-based therapies are, therefore, needed. Calcitonin gene-related peptide (CGRP) is recognized as crucial in the pathophysiology of migraine, and new compounds that target the peptide have been increasingly explored in recent years. First tested were CGRP receptor antagonists; they proved effective in acute migraine treatment in several trials, but were discontinued due to liver toxicity in long-term administration.
Therapeutic agents that block the calcitonin gene–related peptide (CGRP) signaling pathway are a highly anticipated and promising new drug class for migraine therapy, especially after reports that small-molecule CGRP-receptor antagonists are efficacious for both acute migraine treatment and migraine prevention. Using XenoMouse technology, we successfully generated AMG 334, a fully human monoclonal antibody against the CGRP receptor. Here we show that AMG 334 competes with [125I]-CGRP binding to the human CGRP receptor, with a Ki of 0.02 nM. AMG 334 fully inhibited CGRP-stimulated cAMP production with an IC50 of 2.3 nM in cell-based functional assays (human CGRP receptor) and was 5000-fold more selective for the CGRP receptor than other human calcitonin family receptors, including adrenomedullin, calcitonin, and amylin receptors.
Migraine is a highly prevalent headache disease that typically affects patients during their most productive years. Despite significant progress in understanding the underlying pathophysiology of this disorder, its treatment so far continues to depend on drugs that, in their majority, were not specifically designed for this purpose. The neuropeptide calcitonin gene-related peptide (CGRP) has been indicated as playing a critical role in the central and peripheral pathways leading to a migraine attack.
Migraine is a complex disorder of the brain that is common and highly disabling. As understanding of the neural pathways has advanced, and it has become clear that the vascular hypothesis does not explain the disorder, new therapeutic avenues have arisen. One such target is calcitonin gene-related peptide (CGRP)-based mechanisms. CGRP is found within the trigeminovascular nociceptive system widely from the trigeminal ganglion to second-order and third-order neurons and in regulatory areas in the brainstem.
Calcitonin gene-related peptide (CGRP) is a 37-amino-acid neuropeptide whose involvement in migraine pathophysiology is well established. Originally migraine was believed to be a disease of the vasculature, but research has highlighted this to be a disease of the brain with CGRP playing an important role. While targeting CGRP using small molecule antagonists against the receptor has been effective, long-term use of these agents has not been possible due to safety concerns and/or formulation challenges.
Migraine is a neurological disorder that manifests as a debilitating headache associated with altered sensory perception. The neuropeptide calcitonin gene-related peptide (CGRP) is now firmly established as a key player in migraine. Clinical trials carried out during the past decade have proved that CGRP receptor antagonists are effective for treating migraine, and antibodies to the receptor and CGRP are currently under investigation. Despite this progress in the clinical arena, the mechanisms by which CGRP triggers migraine remain uncertain.
In The Lancet Neurology, David Dodick and colleagues1 introduce monoclonal antibodies into the specialty of primary headache therapy. They report findings from a randomised, placebo-controlled, double-blind, phase 2 clinical trial of LY2951742, a neutralising humanised monoclonal antibody against calcitonin gene-related peptide (CGRP), for migraine prevention. The subcutaneous administration of LY2951742 once every 2 weeks reduced the mean number of migraine headache days per 28-day period between baseline and weeks 9–12 (primary endpoint; least-squares mean difference −1·2, 90% CI −1·9 to −0·6; p=0·0030) in a population with a high frequency of migraine; the antibody was also superior to placebo in several secondary endpoints after 12 weeks of treatment.