Significance of serum ribavirin concentration in combination therapy of interferon and ribavirin for chronic hepatitis C.
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.
Arase
Yasuji
Y
Department of Gastroenterology, Toranomon Hospital, Toranomon, Minato-ku, Tokyo, Japan. es9y-ars@asahi-net.or.jp
Ikeda
Kenji
K
Tsubota
Akihito
A
Suzuki
Fumitaka
F
Suzuki
Yoshiyuki
Y
Saitoh
Satoshi
S
Kobayashi
Masahiro
M
Akuta
Norio
N
Someya
Takashi
T
Hosaka
Tetsuya
T
Sezaki
Hitomi
H
Kobayashi
Mariko
M
Kumada
Hiromitsu
H
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*
D000077190:Interferon alpha-2; D016898:Interferon-alpha; D012367:RNA, Viral; D011994:Recombinant Proteins; D012254:Ribavirin