Olcegepant

Sex‐dependent vascular effects of transient receptor potential (TRP) channels and sex dimorphism in migraine are not yet fully characterized. We investigated the differential vasoactive effects of TRP ankyrin 1 (TRPA1), TRP melastatin 3 (TRPM3) and TRP vanilloid 1 (TRPV1) channels, their pharmacological mechanism(s), and localization and expression in human isolated blood vessels.

Agonist responses to cinnamaldehyde (TRPA1), pregnenolone sulfate (PregS, TRPM3) or capsaicin (TRPV1) were analysed using wire myography in segments of human coronary (HCAs) and middle meningeal (HMMAs) arteries from men and women. The mechanisms involved in these responses were investigated using the antagonists/blockers/inhibitors: HC‐030031 (TRPA1), isosakuranetin (TRPM3), capsazepine (TRPV1), olcegepant (calcitonin gene‐related peptide [CGRP] receptor), L‐NAME (nitric oxide synthase [NOS]), indomethacin (cyclooxygenase [COX]), TRAM‐34 + apamin (K+ channels) or MK‐801 (N‐methyl‐d‐aspartate [NMDA] receptor). Fluorescence microscopy, quantitative polymerase chain reaction (qPCR), and western blotting were performed to investigate their location and expression, respectively.

In HCAs and HMMAs, (i) capsaicin‐induced relaxation remained unchanged after the above‐mentioned antagonists/blockers/inhibitors and (ii) cinnamaldehyde‐induced relaxation was blocked by olcegepant. PregS‐induced maximal relaxation was significantly enhanced in isolated arteries from females compared with males and was inhibited after isosakuranetin, MK‐801 or L‐NAME. TRPM3 mRNA and protein expression, along with NMDA protein levels, were higher in arteries from females than males.

Modulation of vascular tone in HCAs and HMMAs by activation of TRPM3 is sex‐dependent, likely involving NMDA receptors. This represents a new therapeutic direction, targeting sex dimorphism in migraine and its related cardiovascular events.

Protease activated receptor 2 (PAR2) is a G-protein coupled receptor expressed in meningeal neurons, fibroblasts and mast cells that may be targeted to treat migraine. MEDI0618, a fully humanized PAR2 monoclonal antibody, engineered to enhance FcRn-dependent recycling and currently in clinical development, was evaluated in human and rodent in vitro assays, in multiple murine in vivo migraine models and in a model of post-traumatic headache.MEDI0618 bound specifically and with high affinity to cells expressing human PAR2 (hPAR2) and prevented matriptase-induced increase in cytosolic calcium. Similarly, MEDI0618 prevented matriptase-induced calcium in primary fibroblasts and microvascular endothelial cells from human dura mater. MEDI0618 had no effect on hPAR1 receptors. Single-cell calcium imaging of acutely dissociated mouse trigeminal ganglion neurons confirmed expression and functionality of mouse PAR2. Studies in vivo used evoked cutaneous allodynia as a surrogate of headache-like pain and, in some experiments, rearing as a measure of non-evoked headache pain. MEDI0618 was administered subcutaneously to C57BL6/J female mice prior to induction of migraine-like pain with (i) systemic nitroglycerin or compound 48/80 (mast cell degranulator); or (ii) with supradural compound 48/80 or an inflammatory mediator (IM) cocktail. To assess possible efficacy against CGRP receptor (CGRP-R)-independent pain, MEDI0618 was also evaluated in the IM model in animals pretreated with systemic olcegepant (CGRP-R antagonist). Migraine-like pain was also induced by inhalational umbellulone, a TRPA1 agonist, in animals primed with restraint stress in the presence or absence of MEDI0618 as well as in a model of post-traumatic headache pain induced by a mild traumatic brain injury.MEDI0618 prevented cutaneous allodynia elicited by systemic nitroglycerin, compound 48/80 and from supradural compound 48/80 and IM. Systemic olcegepant completely blocked periorbital cutaneous allodynia induced by supradural CGRP but failed to reduce IM-induced cutaneous allodynia. In contrast, MEDI0618 fully prevented IM-induced cutaneous allodynia, regardless of pretreatment with olcegepant. Umbellulone elicited cutaneous allodynia only in restraint stress-primed animals, which was prevented by MEDI0618. MEDI0618 prevented the decrease in rearing behaviour elicited by compound 48/80. However, MEDI0618 did not prevent mild traumatic brain injury-related post-traumatic headache measures.These data indicate that MEDI0618 is a potent and selective inhibitor of PAR2 that is effective in human and rodent in vitro cell systems. Further, blockade of PAR2 with MEDI0618 was effective in all preclinical migraine models studied but not in a model of post-traumatic headache. MEDI0618 may represent a novel therapy for migraine prevention with activity against CGRP-dependent and independent attacks.