title: Low risk of adefovir resistance in lamivudine-resistant chronic hepatitis B patients treated with adefovir plus lamivudine combination therapy: two-year follow-up.
abstract: OBJECTIVE
  We studied the long-term efficacy (median follow-up of 28 months) of adefovir (ADV) in combination with lamivudine (LAM) in 132 LAM-resistant Japanese patients with chronic genotype C-dominant hepatitis B virus (HBV) infection.
  
  
  METHODS
  The viral response (undetectable HBV-DNA by PCR assay) and the predictor of viral response were evaluated. The emergence of ADV-resistant mutants was investigated during the combination therapy.
  
  
  RESULTS
  The cumulative probability of viral response was 69% at 12 months, and 81% at 24 months. Multivariate analysis identified baseline HBe antigen status (P=0.0001), aspartate aminotransferase level (AST) (P=0.001) and HBV-DNA level (P=0.002) as determinants of viral response to treatment. At the beginning of ADV therapy, substitutions at rtA181 (rtA181T and rtA181S) were identified in 3 patients (2.3%). In the remaining 129 patients, the rtM204 mutants were identified at baseline, and two (1.6%) of the 129 patients developed new ADV-resistant mutants; one was rtA181S and another was rtA181T plus rtN236T mutation.
  
  
  CONCLUSIONS
  Adefovir and lamivudine combination therapy effectively suppressed viral replication and maintained the efficacy well in LAM-resistant patients with chronic HBV infection. Genotypic analysis indicated that the emergence of ADV-resistant mutants is rare, at least over a period of 2 years, in patients with combination therapy.
authors.affiliation: Department of Hepatology, Toranomon Hospital, 2-2-2 Toranomon, Minato-ku, Tokyo 105-8470, Japan. h-ooga@mx1.harmonix.ne.jp
authors.forename: Hiromi
authors.initials: H
authors.lastname: Yatsuji
authors.forename: Fumitaka
authors.initials: F
authors.lastname: Suzuki
authors.forename: Hitomi
authors.initials: H
authors.lastname: Sezaki
authors.forename: Norio
authors.initials: N
authors.lastname: Akuta
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Kawamura
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Hosaka
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Saitoh
authors.forename: Yasuji
authors.initials: Y
authors.lastname: Arase
authors.forename: Kenji
authors.initials: K
authors.lastname: Ikeda
authors.forename: Sachiyo
authors.initials: S
authors.lastname: Watahiki
authors.forename: Satomi
authors.initials: S
authors.lastname: Iwasaki
authors.forename: Mariko
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Kumada
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D000998:Antiviral Agents / Q000494:pharmacology / Q000627:therapeutic use*; D004279:DNA, Viral / Q000097:blood; D004305:Dose-Response Relationship, Drug; D024882:Drug Resistance, Viral / Q000235:genetics*; D004359:Drug Therapy, Combination; D005260:Female; D005500:Follow-Up Studies; D005838:Genotype; D006515:Hepatitis B virus / Q000235:genetics; D019694:Hepatitis B, Chronic / Q000188:drug therapy* / Q000235:genetics*; D006801:Humans; D019259:Lamivudine / Q000494:pharmacology / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009154:Mutation / Q000235:genetics; D063065:Organophosphonates / Q000494:pharmacology / Q000627:therapeutic use*; D012307:Risk Factors; D016896:Treatment Outcome; D014779:Virus Replication / Q000187:drug effects
chemical_list: D000998:Antiviral Agents; D004279:DNA, Viral; D063065:Organophosphonates; D019259:Lamivudine; C053001:adefovir; D000225:Adenine