Vercirnon is an orally bioavailable antagonist of chemokine receptor 9 (CCR9) with an IC50 value of 5.4 nM for inhibition of CCL25-induced calcium mobilization in Molt-4 cells. It is selective for CCR9 over CCR1-12 and CX3CR1-7 (IC50s = >10 μM for all). It also inhibits CCL25-induced Molt-4 chemotaxis in 0.1% BSA/HBSS and in 100% human AB serum (IC50s = 3.5 and 33.4 nM, respectively), as well as chemotaxis of human T cells stimulated by retinoic acid (RA) and mouse and rat thymocytes. Vercirnon binds allosterically to the intracellular side of CCR9 and prevents G protein coupling.
