title: Resistance analysis of the hepatitis C virus NS3 protease inhibitor asunaprevir.
abstract: Asunaprevir (BMS-650032) is a potent hepatitis C virus (HCV) NS3 protease inhibitor demonstrating efficacy in alfa interferon-sparing, direct-acting antiviral dual-combination regimens (together with the NS5A replication complex inhibitor daclatasvir) in patients chronically infected with HCV genotype 1b. Here, we describe a comprehensive in vitro genotypic and phenotypic analysis of asunaprevir-associated resistance against genotypes 1a and 1b using HCV replicons and patient samples obtained from clinical studies of short-term asunaprevir monotherapy. During genotype 1a resistance selection using HCV replicons, the primary NS3 protease substitutions identified were R155K, D168G, and I170T, which conferred low- to moderate-level asunaprevir resistance (5- to 21-fold) in transient-transfection susceptibility assays. For genotype 1b, a higher level of asunaprevir-associated resistance was observed at the same selection pressures, ranging from 170- to 400-fold relative to the wild-type control. The primary NS3 protease substitutions identified occurred predominantly at amino acid residue D168 (D168A/G/H/V/Y) and were associated with high-level asunaprevir resistance (16- to 280-fold) and impaired replication capacity. In asunaprevir single-ascending-dose and 3-day multiple-ascending-dose studies in HCV genotype 1a- or 1b-infected patients, the predominant pre-existing NS3 baseline polymorphism was NS3-Q80K. This substitution impacted initial virologic response rates in a single-ascending-dose study, but its effects after multiple doses were more ambiguous. Interestingly, for patient NS3 protease sequences containing Q80 and those containing K80, susceptibilities to asunaprevir were comparable when tested in an enzyme assay. No resistance-associated variants emerged in these clinical studies that significantly impacted susceptibility to asunaprevir. Importantly, asunaprevir-resistant replicons remained susceptible to an NS5A replication complex inhibitor, consistent with a role for asunaprevir in combination therapies.
authors.affiliation: Bristol-Myers Squibb, Research and Development, Wallingford, Connecticut, USA. Fiona.mcphee@bms.com
authors.forename: Fiona
authors.initials: F
authors.lastname: McPhee
authors.forename: Jacques
authors.initials: J
authors.lastname: Friborg
authors.forename: Steven
authors.initials: S
authors.lastname: Levine
authors.forename: Chaoqun
authors.initials: C
authors.lastname: Chen
authors.forename: Paul
authors.initials: P
authors.lastname: Falk
authors.forename: Fei
authors.initials: F
authors.lastname: Yu
authors.forename: Dennis
authors.initials: D
authors.lastname: Hernandez
authors.forename: Min S
authors.initials: MS
authors.lastname: Lee
authors.forename: Susan
authors.initials: S
authors.lastname: Chaniewski
authors.forename: Amy K
authors.initials: AK
authors.lastname: Sheaffer
authors.forename: Claudio
authors.initials: C
authors.lastname: Pasquinelli
mesh_terms: D000293:Adolescent; D000328:Adult; D000998:Antiviral Agents / Q000627:therapeutic use*; D045744:Cell Line, Tumor; D024882:Drug Resistance, Viral / Q000235:genetics; D005260:Female; D005838:Genotype; D006526:Hepatitis C / Q000188:drug therapy / Q000235:genetics / Q000821:virology; D006801:Humans; D007546:Isoquinolines / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009842:Oligopeptides / Q000627:therapeutic use; D011480:Protease Inhibitors / Q000627:therapeutic use*; D013449:Sulfonamides / Q000627:therapeutic use*; D017361:Viral Nonstructural Proteins / Q000037:antagonists & inhibitors*; D055815:Young Adult; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
chemical_list: D000998:Antiviral Agents; D007546:Isoquinolines; D009842:Oligopeptides; D011480:Protease Inhibitors; D013449:Sulfonamides; D017361:Viral Nonstructural Proteins; C084422:NS3 protein, hepatitis C virus; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases; C486464:telaprevir; C571889:asunaprevir