Inhibitory assays |
Inhibition of HCV NS3/4A protease activity in reaction mixtures containing MK-5172, vaniprevir, or the reference compounds danoprevir and TMC435 was determined in a time-resolved fluorescence assay. Cell-based HCV replicon assays were conducted in genotype 1b (con1) stable cell line HB1 (26) or a gt2a cell line (JFH) in the presence of either 10% fetal bovine serum (FBS) or 40% normal human serum (NHS). For in vitro resistance selections, 100,000 HB1 cells were seeded into a T162 Z-top flask and cultured in the presence of 0.5 mg/ml G418 and the desired concentration of MK-5172. Cells were cultured for approximately 3 weeks with regular exchanges of medium until sufficient cell death had occurred to enable distinct colonies to form. After expansion, total RNA was isolated, used as a template to generate NS3/4a cDNA, and sequenced using conventional molecular biology techniques. |
Applications |
MK-5172 demonstrated subnanomolar to low-nanomolar EC50s against genotypes 1a, 1b, and 2a. MK-5172 was efficacious across the genetically diverse range of genotype 1 infections encountered in clinical settings with EC50s ranged narrowly between 0.3 and 5.9 nM. In Genotype 1b replicon cells, pre- treatment with MK-5172 resulted in little apparent cell growth and limited recovery of replicon RNA levels. |
Application |
MK-5172 demonstrated low to moderate clearance and a modest half-life in both rat and dog. Oral administration of MK-5172 (1 mg/kg) demonstrated modest bioavailability of 12 to 13%, with moderate plasma exposure in both species. The 24-h trough liver concentrations were 0.2 μM in rat and 1.4 μM in dog (1 mg/kg), yielding exposure multiples of 27- to 200-fold over the serum-adjusted replicon EC50. In chronic-HCV-infected chimpanzees harboring gt1a, gt1b, or gt1a NS3 R155K infections, treatment with MK-5172 (1 mg/kg, b.i.d.) demonstrated efficacy in vivo. |
| 产品描述 |
MK-5172 is a selective inhibitor of Hepatitis C Virus NS3/4a Protease [1].
Hepatitis C (HCV) virus is a member of the Flaviviridae family of viruses in the Hepacivirus genus and encoded by a 9.6-kb positive strand RNA genome [2].
In biochemical assays, MK-5172 inhibited a series of major genotypes and common mutants in a HCV NS3/4A protease enzymatic assay. In a cell-based replicon system, MK-5172 inhibited HCV with EC50 values of 2 nM against genotype 1a, 0.5 nM against genotype 1b, 8 nM against genotype 2a and 13 nM against genotype 3. Also, MK-5172 is effective against HCV genotypes 1a, 2a, 1b, 2b and 3a [2].
Treatment three chronically HCV-infected chimpanzees with a dose of 1 mg/kg twice daily for 7 days, Two of the chimpanzees had wild-type (WT) gt1a or gt1b infections with high viral titers (~106 IU/ml). A third chimpanzee had a modest viral titer (~104 IU/ml) that was gt1a NS3 R155K virus. MK-5172 (1 mg/kg) reduced viral titer of the gt1a (WT) infection to ~100 IU/ml within 2 days and the gt1b infection to 20 IU/ml. The gt1a NS3 R155K-infected chimp experienced a rapid ~2-log reduction in viral titer [2].
References:
[1]. Harper S, McCauley JA, Rudd MT, et al. Discovery of MK-5172, a Macrocyclic Hepatitis C Virus NS3/4a Protease Inhibitor. ACS Med Chem Lett, 2012, 3(4): 332-336.
[2]. Summa V, Ludmerer SW, McCauley JA, et al. MK-5172, a selective inhibitor of hepatitis C virus NS3/4a protease with broad activity across genotypes and resistant variants. Antimicrob Agents Chemother, 2012, 56(8): 4161-4167. |
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