Calcitonin gene-related peptide (CGRP) receptor antagonists: Investigations of a pyridinone template

Calcitonin gene-related peptide (CGRP) receptor antagonists: Heterocyclic modification of a novel azepinone lead

In our efforts to identify orally bioavailable CGRP receptor antagonists, we previously discovered a novel series of orally available azepinone derivatives that unfortunately also exhibited the unwanted property of potent time-dependent human CYP3A4 inhibition. Through heterocyclic replacement of the indazole ring, we discovered a series of heterocycle derivatives as high-affinity CGRP receptor antagonists. Some of them showed reasonable oral exposures, and the imidazolone derivatives that showed good oral exposure also exhibited substantially reduced time-dependent CYP3A4 inhibition. Several compounds showed strong in vivo efficacy in our marmoset facial blood flow assay with up to 87% inhibition of CGRP-induced activity. However, oral bioavailability generally remained low, emphasizing the challenges we and others encountered in discovering clinical development candidates for this difficult Class B GPCR target.

Identification of Small-Molecule Positive Modulators of Calcitonin-like Receptor-Based Receptors

Class B G protein-coupled receptors are highly therapeutically relevant but challenges remain in identifying suitable small-molecule drugs. The calcitonin-like receptor (CLR) in particular is linked to conditions such as migraine, cardiovascular disease, and inflammatory bowel disease. The CLR cannot act as a cell-surface receptor alone but rather must couple to one of three receptor activity-modifying proteins (RAMPs), forming heterodimeric receptors for the peptides adrenomedullin and calcitonin gene-related peptide. These peptides have extended binding sites across their receptors. This is one reason why there are few small-molecule ligands that can modulate these receptors. Here we describe small molecules that are able to positively modulate the signaling of the CLR with all three RAMPs but are not active at the related calcitonin receptor. These compounds were selected from a β-arrestin recruitment screen, coupled with rounds of medicinal chemistry to improve their activity. Translational potential is shown as the compounds can positively modulate cAMP signaling in a vascular cell line model. Binding experiments do not support an extracellular domain binding site; however, molecular modeling reveals potential allosteric binding sites in multiple receptor regions. These are the first small-molecule positive modulators described for the CLR:RAMP complexes.

Calcitonin gene-related peptide receptor antagonists for the treatment of migraine: a patent review

BACKGROUND

Migraine is a debilitating headache disorder which affects approximately 12% of the general population and is the cause of significant loss of productivity (i.e., lost time from work or school) for those afflicted. The current standard of care, the 5-HT(1B/1D) agonists known as triptans, is contraindicated in patients with cardiovascular disease due to their inherent vasoconstrictive activity; thus, there is a need to develop an alternative therapy for the treatment of the disorder.

OBJECTIVE

This article reviews patent publications related to the use of small molecule calcitonin gene-related peptide (CGRP) receptor antagonists for the treatment of migraine that have appeared in the literature within the past decade. The commentary is supplemented by information presented in journal articles and focuses on the activity of several major pharmaceutical companies in the field.

CONCLUSION

Two small molecule CGRP receptor antagonists, olcegepant and telcagepant, have been shown to be clinically efficacious in the treatment of migraine, and thus provide validation of this novel therapeutic mechanism.

Inhibition of calcitonin gene-related peptide function: a promising strategy for treating migraine

The neuropeptide calcitonin gene-related peptide (CGRP) is implicated in the underlying pathology of migraine. Serum levels of CGRP, which are elevated during a migraine attack, have been reported to return to normal with alleviation of pain. In addition, CGRP administration has been shown to cause a migraine-like headache in susceptible individuals. Importantly, CGRP receptors are found on many cell types within the trigeminovascular system that are thought to play important roles in controlling inflammatory and nociceptive processes. Based on these findings, it was proposed that blockage of CGRP receptor function and, hence, the physiological effects of CGRP would be effective in aborting a migraine attack. This review will summarize key preclinical data that support the therapeutic potential of using CGRP receptor antagonists or molecules that bind CGRP within the context of current neurovascular theories on migraine pathology.

Discovery of (R)-4-(8-fluoro-2-oxo-1,2-dihydroquinazolin-3(4H)-yl)-N-(3-(7-methyl-1H-indazol-5-yl)-1-oxo-1-(4-(piperidin-1-yl)piperidin-1-yl)propan-2-yl)piperidine-1-carboxamide (BMS-694153): a potent antagonist of the human calcitonin gene-related peptide receptor for migraine with rapid and efficient intranasal exposure

Calcitonin gene-related peptide (CGRP) has been implicated in the pathogenesis of migraine. Early chemistry leads suffered from modest potency, significant CYP3A4 inhibition, and poor aqueous solubility. Herein, we describe the optimization of these leads to give 4 (BMS-694153), a molecule with outstanding potency, a favorable predictive toxicology profile, and remarkable aqueous solubility. Compound 4 has good intranasal bioavailability in rabbits and shows dose-dependent activity in validated in vivo and ex vivo migraine models.