title: von Willebrand factor antigen: a novel on-treatment predictor of response to antiviral therapy in chronic hepatitis C genotypes 1 and 4.
abstract: BACKGROUND
  Levels of von Willebrand factor antigen (vWF-Ag) increase during combination antiviral therapy of chronic hepatitis C (CHC). The present study investigates the association between these changes in vWF-Ag levels and response to treatment.
  
  
  METHODS
  Changes in levels of vWF-Ag on antiviral combination treatment in 184 patients with CHC genotype 1 or 4 infections were measured prospectively and effect on response was studied.
  
  
  RESULTS
  High on-treatment levels of vWF-Ag were associated with relapse (P<0.01) and low on-treatment levels with sustained virological response (SVR). Receiver operating characteristic curve analysis showed that vWF-Ag levels of <300% at week 12 of therapy have a positive predictive value (PPV) of 78% for SVR. In early virological response (EVR) patients, the PPV of vWF-Ag levels <300% at week 12 was 74%. An even higher PPV of 88% in complete EVRs (undetectable HCV RNA at week 12) was observed for the same cutoff value at week 12.
  
  
  CONCLUSIONS
  On-treatment levels of vWF-Ag can be utilized as an additional predictive marker for response to antiviral therapy. This is especially relevant in EVR patients because EVR alone only has a PPV of 58-72% on SVR, which increased to 74%, when factoring in vWF-Ag levels <300% at week 12, and to 88% in complete EVRs; therefore, measurement of vWF-Ag levels at week 12 is helpful. EVR patients that are above the cutoff values for vWF-Ag that make SVR very probable might profit from an extension of therapy to 72 weeks.
authors.affiliation: Institution Department of Gastroenterology and Hepatology, Medical University Vienna, Austria.
authors.forename: Sibylle
authors.initials: S
authors.lastname: Pramhas
authors.forename: Monika
authors.initials: M
authors.lastname: Homoncik
authors.forename: Peter
authors.initials: P
authors.lastname: Ferenci
authors.forename: Arnulf
authors.initials: A
authors.lastname: Ferlitsch
authors.forename: Thomas
authors.initials: T
authors.lastname: Scherzer
authors.forename: Alfred
authors.initials: A
authors.lastname: Gangl
authors.forename: Markus
authors.initials: M
authors.lastname: Peck-Radosavljevic
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000998:Antiviral Agents / Q000627:therapeutic use*; D004359:Drug Therapy, Combination; D005260:Female; D005838:Genotype; D019698:Hepatitis C, Chronic / Q000188:drug therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012008:Recurrence; D012254:Ribavirin / Q000008:administration & dosage* / Q000627:therapeutic use*; D014841:von Willebrand Factor / Q000276:immunology* / Q000378:metabolism
chemical_list: D000998:Antiviral Agents; C029417:Von Willebrand antigen; D014841:von Willebrand Factor; D012254:Ribavirin