In vitro activity: Elbasvir shows potent activity against genotype 1a and 1b replicons, with EC90 of 0.006 nM for both the wild-type 1a_H77 and 1b_con1 replicons. Elbasvir inhibits genotype 3 replicons with EC90 of 0.12 nM. Elbasvir (0.06 nM, 0.6 nM, and 6 nM) demonstrates dose-dependent suppression of resistant genotype 1a replicons, illustrated by the reductions in colony counts at higher doses. Elbasvir is highly potent against HCV replicons bearing NS5A sequences from GT1a, -1b, -2a(31L), -3a, -4a, -5a, and -6, with EC50s in the low-picomolar range.

Kinase Assay: Elbasvir is a HCV NS5A inhibitor which prevents hepatitis C viral RNA replication and virion assembly with median EC50 values ranging from 0.2 to 3600 pmol/L, based on genotypes.

Cell Assay: Elbasvir (formerly known as MK-8742; MK8742; trade name Zepatier) is a potent NS5A (nonstructural protein 5A) inhibitor with anti-HCV (hepatitis C virus) activities against different HCV genotypes.