Simeprevir is a potent inhibitor of HCV NS3/4A protease with Ki value of 0.36 nM [1].
The hepatitis C virus (HCV) NS3/4A protease is a serine protease encoded by HCV and is responsible for cleavage at four sites of the HCV polyprotein. It is essential for viral replication [1].
In Huh-7-Rep cells, Simeprevir inhibited HCV replication with EC50 of 7.8 nM [1]. In the Huh7-Luc HCV genotype 1b replicon cell line, Simeprevir inhibited HCV replication with EC50 and EC90 values of 8 nM and 24 nM respectively in a dose dependent way [2].
In ninety-two naive, HCV genotype 1-infected patients, treatment with Simeprevir (50 or 100 mg QD) for 12 or 24 weeks and peginterferon α-2a/ribavirin (PegIFNα-2a/RBV) for 24 or 48 weeks or PegIFN α-2a/RBV for 48 weeks lonely (PR48 group), RNA reductions in the 4 week were -5.2,-5.2 and-2.9 log10IU/mL for Simeprevir 50 mg combined, 100 mg combined and PR48 groups, respectively, which suggested Simeprevir reduced HCV RNA more rapidly and substantially. Also, Simeprevir increased the virologic response rates [3].
References:
[1]. Raboisson P, de Kock H, Rosenquist A, et al. Structure-activity relationship study on a novel series of cyclopentane-containing macrocyclic inhibitors of the hepatitis C virus NS3/4A protease leading to the discovery of TMC435350. Bioorg Med Chem Lett, 2008, 18(17): 4853-4858.
[2]. Lin TI, Lenz O, Fanning G, et al. In vitro activity and preclinical profile of TMC435350, a potent hepatitis C virus protease inhibitor. Antimicrob Agents Chemother, 2009, 53(4): 1377-1385.
[3]. Hayashi N, Seto C, Kato M, et al. Once-daily simeprevir (TMC435) with peginterferon/ribavirin for treatment-na?ve hepatitis C genotype 1-infected patients in Japan: the DRAGON study. J Gastroenterol, 2014, 49(1): 138-147.
