Olcegepant (BIBN-4096) is an effective and selective non-peptide calcitonin gene-related peptide 1 (CGRP1) receptor antagonist (IC50 of 0.03 nM and Ki of 14.4 pM for human CGRP).

CGRP (human):14.4 pM (ki), CGRP1:0.03 nM

Olcegepant exhibits exceptional efficacy at primate CGRP receptors, demonstrating a high affinity (Ki) of 14.4±6.3 (n=4) pM for human CGRP receptors, surpassing that of the endogenous ligand CGRP and demonstrating a 150-fold greater affinity than the peptidic antagonist CGRP8-37. It competitively antagonizes CGRP-induced concentration-dependent relaxation, effectively reversing CGRP-mediated vasodilation in human cerebral vessels and inhibiting neurogenic vasodilation in a surrogate animal model for migraine pathophysiology. This suggests that Olcegepant, acting as a CGRP receptor antagonist, may be a potential novel abortive treatment for migraines. Its competitive antagonism has also been confirmed in SK-N-MC cells, with its effects observed in isolated human cerebral, coronary, and omental arteries using sensitive myograph techniques[1][2][3].

Pre-treatment with Olcegepant (900 μg/kg) inhibits capsaicin-induced Fos expression in the spinal trigeminal nucleus by 57%, without altering phosphorylated extracellular signal-regulated kinase expression in the trigeminal ganglion. Olcegepant (1-30 μg/kg, i.v.) suppresses CGRP effects on facial blood flow in marmosets and significantly reduces mechanical allodynia in CCI-ION rats (0.3-0.9 mg/kg, i.v.). Additionally, Olcegepant (0.6 mg/kg, i.v.) decreases c-Fos immunolabeled cells and ATF3 transcript upregulation, but not interleukin-6, in the trigeminal ganglion of CCI-ION rats [2][4][5].