title: Changes in hepatitis C viral load during first 14 days can predict the undetectable time point of serum viral load by pegylated interferon and ribavirin therapy.
abstract: OBJECTIVE
  In the treatment of chronic hepatitis C, pegylated interferon (PEG-IFN) and ribavirin combination therapy must be continued for an adequate duration to improve the rate of sustained virological response. We attempted to predict the time point at which serum hepatitis C virus (HCV) RNA are undetectable during combination therapy.
  
  
  METHODS
  Patients with HCV genotype 1b were enrolled in a model preparation (n = 35) and a validation group (n = 70). All patients received PEG-IFN-α-2b/ribavirin combination therapy for at least 48 weeks, and serological samples were screened a minimum of 17 times during the therapy. Serum HCV RNA were measured by the Abbott RealTime HCV assay. Using the HCV dynamics model described by Neumann et al., we used multiple linear regression analysis to select factors that affected the undetectable time point.
  
  
  RESULTS
  Difference in viral load between weeks 1 and 2 was the only predictive factor for the undetectable time point of serum HCV RNA (r(2)  = 0.67, P < 0.0005), and we derived the following prediction equation: undetectable time point (week) = 13.495 × (viral load at day 14 [log IU/mL] - viral load at day 7 [log IU/mL]) + 25.456. The equation was applicable to the validation group.
  
  
  CONCLUSIONS
  We created a formula for predicting the undetectable time point from viral load measurements early in PEG-IFN-α-2b/ribavirin combination therapy. An early response reflects sensitivity to therapy, and the estimation of an undetectable time point would be useful for determining the optimal duration of treatment for chronic hepatitis C patients.
authors.affiliation: Division of Gastroenterology and Hepatology, Musashino Red Cross Hospital, Tokyo, Japan Abbott Molecular, Des Plaines, Illinois, USA.
authors.forename: Jun
authors.initials: J
authors.lastname: Itakura
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Asahina
authors.forename: Nobuharu
authors.initials: N
authors.lastname: Tamaki
authors.forename: Itsuko
authors.initials: I
authors.lastname: Hirayama
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Yasui
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Tanaka
authors.forename: Mitsuaki
authors.initials: M
authors.lastname: Sato
authors.forename: Ken
authors.initials: K
authors.lastname: Ueda
authors.forename: Teiji
authors.initials: T
authors.lastname: Kuzuya
authors.forename: Kaoru
authors.initials: K
authors.lastname: Tsuchiya
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Nakanishi
authors.forename: Masayuki
authors.initials: M
authors.lastname: Kurosaki
authors.forename: Gretchen S
authors.initials: GS
authors.lastname: Gabriel
authors.forename: George J
authors.initials: GJ
authors.lastname: Schneider
authors.forename: Namiki
authors.initials: N
authors.lastname: Izumi