Olcegepant (BIBN-4096) is a potent and selective non-peptide antagonist of the calcitonin gene-related peptide 1 (CGRP1) receptor with IC₅₀ of 0.03 nM and K_i of 14.4 pM for human CGRP^[1][2]. IC50 & Target: IC50: 0.03 nM (CGRP1)^[1]
Ki: 14.4 pM (hCGRP)^[2] In Vitro: Olcegepant possesses higher affinity for the human CGRP receptor than the endogenous ligand CGRP and 150-fold higher affinity compared to the peptidic antagonist CGRP8-37. Olcegepant reverses CGRP-mediated vasodilation in human cerebral vessels and inhibits neurogenic vasodilation in a surrogate animal model of migraine pathophysiology^[1]. Olcegepant (BIBN4096BS) is extremely potent at primate CGRP receptors exhibiting an affinity (K_i) for human CGRP receptors of 14.4±6.3 (n=4) pM^[2]. Several lines of evidence suggest that a calcitonin-gene related peptide (CGRP) receptor antagonist may serve as a novel abortive migraine treatment. Olcegepant (BIBN4096BS) exhibits competitive antagonism at the CGRP receptor present in SK-N-MC cells. Isolated human cerebral, coronary, and omental arteries are studied with a sensitive myograph technique. CGRP induces a concentration-dependent relaxation that is antagonized by Olcegepant in a competitive manner^[3]. In Vivo: Olcegepant (BIBN4096BS) in doses between 1 and 30 μg/kg (i.v.) inhibits the effects of CGRP, released by stimulation of the trigeminal ganglion, on facial blood flow in marmoset monkeys^[2]. Pre-treatment with Olcegepant (900 μg/kg) inhibits the capsaicin-induced expression of Fos throughout the spinal trigeminal nucleus by 57%. In contrast, the expression of phosphorylated extracellular signal-regulated kinase in the trigeminal ganglion is not changed by Olcegepant pre-treatment^[4]. Olcegepant (0.3 to 0.9 mg/kg, i.v.) markedly reduces mechanical allodynia in CCI-ION rats. Olcegepant (0.6 mg/kg, i.v.) significantly reduces the number of c-Fos immunolabeled cells in spinal nucleus of the trigeminal nerve and upregulation of ATF3 transcript (a marker of neuron injury) but not that of interleukin-6 in trigeminal ganglion of CCI-ION rats^[5].