title: Significance of serum ribavirin concentration in combination therapy of interferon and ribavirin for chronic hepatitis C.
abstract: OBJECTIVE
  The purpose of this clinical retrospective cohort study was to determine the most suitable ribavirin concentration on combination therapy of interferon (IFN)-ribavirin.
  
  
  METHODS
  Entry criteria were serum HCV-RNA level >/=100 KIU/ml, HCV-genotype 1b, chronic hepatitis, and initial combination treatment of IFN-alpha-2b (6 million units daily for 2 weeks and then 3 times weekly for 6 weeks) and ribavirin (600-800 mg/day) for 8 weeks without stopping or decreasing the dosage of IFN and/or ribavirin. Sixty-eight consecutive patients who satisfied the above criteria were given maintenance therapy for another 16 weeks.
  
  
  RESULTS
  A sustained virological response (SVR) rate of 25.0% (17/68) was seen in all subjects. The SVR rate was 44.0% (11/25) in the high ribavirin group with a serum ribavirin concentration of >/=3,000 ng/ml at 8 weeks after initiation of combination therapy. SVR was significantly dependent at a serum ribavirin level of >/=3,000 ng/ml (p = 0.005). The incidence of discontinuations and dose modifications for combination therapy in patients having a serum ribavirin concentration of >/=3,500 ng/ml 8 weeks after initiation of therapy was 57.1% (4/7). This value was statistically higher than that in patents with <3,500 ng/ml (p = 0.033).
  
  
  CONCLUSIONS
  Our results showed that the most suitable serum ribavirin concentrations are from 3,000 to 3,500 ng/ml 8 weeks after initiation of combination therapy.
authors.affiliation: Department of Gastroenterology, Toranomon Hospital, Toranomon, Minato-ku, Tokyo, Japan. es9y-ars@asahi-net.or.jp
authors.forename: Yasuji
authors.initials: Y
authors.lastname: Arase
authors.forename: Kenji
authors.initials: K
authors.lastname: Ikeda
authors.forename: Akihito
authors.initials: A
authors.lastname: Tsubota
authors.forename: Fumitaka
authors.initials: F
authors.lastname: Suzuki
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Satoshi
authors.initials: S
authors.lastname: Saitoh
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Norio
authors.initials: N
authors.lastname: Akuta
authors.forename: Takashi
authors.initials: T
authors.lastname: Someya
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Hosaka
authors.forename: Hitomi
authors.initials: H
authors.lastname: Sezaki
authors.forename: Mariko
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Kumada
mesh_terms: D000328:Adult; D000368:Aged; D004359:Drug Therapy, Combination; D005260:Female; D019698:Hepatitis C, Chronic / Q000097:blood / Q000188:drug therapy*; D006801:Humans; D000077190:Interferon alpha-2; D016898:Interferon-alpha / Q000008:administration & dosage / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D012367:RNA, Viral / Q000097:blood; D011994:Recombinant Proteins; D012189:Retrospective Studies; D012254:Ribavirin / Q000008:administration & dosage / Q000097:blood* / Q000627:therapeutic use*
chemical_list: D000077190:Interferon alpha-2; D016898:Interferon-alpha; D012367:RNA, Viral; D011994:Recombinant Proteins; D012254:Ribavirin