[CAS NO. 541503-81-5]  Vicriviroc Malate

Vicriviroc binds with higher affinity to CCR5 versus SCH-C (SCH-351125) in competition binding assays with K value of 0.8 nM versus 2.6 nM. Vicriviroc is nearly 6-fold less active than SCH-C (IC50 = 5.8 μM versus 1.1 μM) in attenuating hERG current among voltage-clamped L929 cells, indicating a reduced potential for cardiac effects. Vicriviroc inhibits MIP-1α induced migration of Ba/F3 cells stably expressing recombinant human CCR5, with IC50 of 0.91 nM. In U-87-CCR5 cells, Vicriviroc inhibits intracellular calcium release induced by the ligand RANTES with IC50 of 16 nM, while Vicriviroc treatment alone does not stimulate the release of calcium. Vicriviroc inhibits GTPγS binding to the membranes from HTS-hCCR5 cells induced by RANTES, with IC50 of 4.2 nM. Vicriviroc displays potent antiviral activity against a panel of 30 R5-tropic HIV-1 isolates representing diverse genetic clades, with EC50 values ranging from 0.04 nM to 2.3 nM, and EC90 from 0.45 nM to 18 nM, being more potent (2- to 40-fold) than SCH-C. Vicriviroc is also highly active against a Clade G Russian isolate RU570 with EC90 of 16 nM, which is resistant to inhibition by SCH-C (EC90 > 1 μM). Vicriviroc could target an early step in the viral life cycle prior to reverse transcription and virion maturation, the targets of reverse transcriptase inhibitor and protease inhibitor, respectively. Consistent with the selectivity for CCR5, Vicriviroc is not active against viruses capable of using the CXCR4 coreceptor (R5/X4 or X4 tropic) for infection.