title: Clinical relevance of the HCV protease inhibitor-resistant mutant viral load assessed by ultra-deep pyrosequencing in treatment failure.
abstract: BACKGROUND
  The detection of low frequency mutants in patients with hepatitis C virus (HCV) receiving direct-acting antivirals (DAAs) is still debated. The clinical relevance of the mutant viral load has not yet been evaluated.
  
  
  OBJECTIVE
  To assess the viral load of resistance associated variants (RAVs) in patients at different time points, including the baseline, virological failure and one year after the cessation of therapy.
  
  
  METHODS
  The study included 22 patients who were previously treated with protease inhibitors (PI) (with telaprevir and boceprevir). For each patient, three time points were assessed using ultra-deep pyrosequencing (UDPS).
  
  
  RESULTS
  Baseline mutations were observed in 14/22 patients (64%). At virological failure, RAVs were detected in 18/22 patients (82%). Persistent RAVs were observed in four HCV GT 1a patients (18%). Persistence mutations were found only in HCV GT 1a patients. The baseline relative V36M, R155K, R155T and A156T mutation load of patients with persistent RAVs was significantly higher (P<0.001) than those of patients without persistent RAVs.
  
  
  CONCLUSIONS
  The UDPS follow-up analysis demonstrated that the presence of BOC or TLP-RAVs persist one year after therapy cessation only in HCV GT 1a patients. The relative mutant viral load should be considered prior to any PI based re-treatment. This concept of the baseline mutation viral load must be validated using current therapy and must be validated on a larger cohort.
authors.affiliation: Laboratoire Alphabio, Marseille, France; CRCM, Immunity and Cancer, Inserm, U1068; Institut Paoli-Calmettes; Aix-Marseille Université, UM 105; CNRS, UMR7258, F-13009 Marseille, France.
authors.forename: Sofiane
authors.initials: S
authors.lastname: Mohamed
authors.affiliation: Département d'hépato-gastroenterologie, Hôpital Saint Joseph, Marseille, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Bourliere
authors.affiliation: Département d'hépato-gastroenterologie, Hôpital Saint Joseph, Marseille, France.
authors.forename: Souad
authors.initials: S
authors.lastname: Benali
authors.affiliation: Département d'hépato-gastroenterologie, Hôpital Saint Joseph, Marseille, France.
authors.forename: Valerie
authors.initials: V
authors.lastname: Oules
authors.affiliation: Département d'hépato-gastroenterologie, Hôpital Saint Joseph, Marseille, France.
authors.forename: Paul
authors.initials: P
authors.lastname: Castellani
authors.affiliation: Laboratoire Alphabio, Marseille, France.
authors.forename: Hacène
authors.initials: H
authors.lastname: Khiri
authors.affiliation: Laboratoire Alphabio, Marseille, France.
authors.forename: Claire
authors.initials: C
authors.lastname: Camus
authors.affiliation: Laboratoire Alphabio, Marseille, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Penaranda
authors.affiliation: Hôpital Européen, Marseille, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Chiche
authors.affiliation: Advanced Biological Laboratories (ABL), Luxembourg, Luxembourg.
authors.forename: Dimitri
authors.initials: D
authors.lastname: Gonzalez
authors.affiliation: Advanced Biological Laboratories (ABL), Luxembourg, Luxembourg.
authors.forename: Chalom
authors.initials: C
authors.lastname: Sayada
authors.affiliation: CRCM, Immunity and Cancer, Inserm, U1068; Institut Paoli-Calmettes; Aix-Marseille Université, UM 105; CNRS, UMR7258, F-13009 Marseille, France.
authors.forename: Daniel
authors.initials: D
authors.lastname: Olive
authors.affiliation: Laboratoire Alphabio, Marseille, France; Hôpital Européen, Marseille, France. Electronic address: philippe.halfon@alphabio.fr.
authors.forename: Philippe
authors.initials: P
authors.lastname: Halfon
mesh_terms: D000328:Adult; D000368:Aged; D000998:Antiviral Agents / Q000494:pharmacology / Q000627:therapeutic use*; D024882:Drug Resistance, Viral; D005260:Female; D005838:Genotype; D016174:Hepacivirus / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D019698:Hepatitis C, Chronic / Q000188:drug therapy* / Q000821:virology; D059014:High-Throughput Nucleotide Sequencing; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009842:Oligopeptides / Q000494:pharmacology / Q000627:therapeutic use; D011392:Proline / Q000031:analogs & derivatives / Q000494:pharmacology / Q000627:therapeutic use; D011480:Protease Inhibitors / Q000494:pharmacology / Q000627:therapeutic use*; D012189:Retrospective Studies; D017211:Treatment Failure; D019562:Viral Load
chemical_list: D000998:Antiviral Agents; D009842:Oligopeptides; D011480:Protease Inhibitors; C486464:telaprevir; C512204:N-(3-amino-1-(cyclobutylmethyl)-2,3-dioxopropyl)-3-(2-((((1,1-dimethylethyl)amino)carbonyl)amino)-3,3-dimethyl-1-oxobutyl)-6,6-dimethyl-3-azabicyclo(3.1.0)hexan-2-carboxamide; D011392:Proline
keywords: HCV; Mutant viral load; Protease inhibitors; Ultra-deep pyrosequencing