title: Clinical Resistance to Velpatasvir (GS-5816), a Novel Pan-Genotypic Inhibitor of the Hepatitis C Virus NS5A Protein.
abstract: Velpatasvir (VEL, GS-5816) is a novel pan-genotypic hepatitis C virus (HCV) nonstructural protein 5A (NS5A) inhibitor with activity against genotype 1 (GT1) to GT6 HCV replicons. In a phase 1b 3-day monotherapy study, patients treated with a 150-mg dose of GS-5816 had a mean maximal HCV RNA decline of ≥3.3 log10 IU/ml in GT1a, -1b, -2, -3, and -4. This report characterizes virologic resistance to VEL in these patients. NS5A resistance-associated substitutions (RASs) were detected by deep sequencing (1% cutoff) pretreatment in 22/70 patients, i.e., 10/35 (29%) patients with GT1a, 1/8 (13%) with GT1b, 4/8 (50.0%) with GT2, 5/17 (29.4%) with GT3, and 2/2 (100.0%) with GT4. In GT1a and GT3 patients, pretreatment RASs were associated with a slightly reduced HCV RNA response compared to that of patients without pretreatment RASs; among patients with GT1b, GT2, and GT4, no significant difference in response was observed in those with or without pretreatment RASs. Following treatment, the pattern of emergent RASs was more complex for GT1a than for the other genotypes. In GT1a, substitutions emerged at positions M28, Q30, L31, P32, H58, E92, and Y93, with the most prevalent substitutions at positions Y93, M28, and L31. RASs were observed at two positions in GT1b and GT2 (Y93 and L31), three positions in GT3 (Y93, L31, and E92), and four positions in GT4 (L28, M31, P32L, and Y93). RASs that were present pretreatment persisted through the 48-week follow-up period; however, RASs emerging during treatment were more likely to decline both in prevalence and in frequency within the viral population during follow-up. (This study has been registered at ClinicalTrials.gov under registration no. NCT01740791.).
authors.affiliation: Texas Liver Institute, University of Texas Health Science Center, San Antonio, Texas, USA.
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Lawitz
authors.affiliation: Gilead Sciences, Foster City, California, USA Hadas.Dvory-Sobol@Gilead.com.
authors.forename: Hadas
authors.initials: H
authors.lastname: Dvory-Sobol
authors.affiliation: Gilead Sciences, Foster City, California, USA.
authors.forename: Brian P
authors.initials: BP
authors.lastname: Doehle
authors.affiliation: Gilead Sciences, Foster City, California, USA.
authors.forename: Angela S
authors.initials: AS
authors.lastname: Worth
authors.affiliation: Gilead Sciences, Foster City, California, USA.
authors.forename: John
authors.initials: J
authors.lastname: McNally
authors.affiliation: Gilead Sciences, Foster City, California, USA.
authors.forename: Diana M
authors.initials: DM
authors.lastname: Brainard
authors.affiliation: Gilead Sciences, Foster City, California, USA.
authors.forename: John O
authors.initials: JO
authors.lastname: Link
authors.affiliation: Gilead Sciences, Foster City, California, USA.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Miller
authors.affiliation: Gilead Sciences, Foster City, California, USA.
authors.forename: Hongmei
authors.initials: H
authors.lastname: Mo
mesh_terms: D019943:Amino Acid Substitution; D000998:Antiviral Agents / Q000627:therapeutic use*; D002219:Carbamates / Q000627:therapeutic use*; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D024882:Drug Resistance, Viral / Q000235:genetics*; D015870:Gene Expression; D005838:Genotype; D016174:Hepacivirus / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D019698:Hepatitis C, Chronic / Q000188:drug therapy* / Q000821:virology; D006576:Heterocyclic Compounds, 4 or More Rings / Q000627:therapeutic use*; D006801:Humans; D009154:Mutation; D012367:RNA, Viral / Q000037:antagonists & inhibitors / Q000235:genetics*; D017361:Viral Nonstructural Proteins / Q000037:antagonists & inhibitors / Q000235:genetics*; D012324:RNA-Dependent RNA Polymerase; D001562:Benzimidazoles; D001578:Benzopyrans
chemical_list: D000998:Antiviral Agents; D002219:Carbamates; D006576:Heterocyclic Compounds, 4 or More Rings; D012367:RNA, Viral; D017361:Viral Nonstructural Proteins; C087036:NS-5 protein, hepatitis C virus; D012324:RNA-Dependent RNA Polymerase; C000604171:velpatasvir; D001562:Benzimidazoles; D001578:Benzopyrans