title: Rescue therapy for lamivudine-resistant chronic hepatitis B: comparison between entecavir 1.0 mg monotherapy, adefovir monotherapy and adefovir add-on lamivudine combination therapy.
abstract: OBJECTIVE
  There have been no reports comparing the therapeutic results of adefovir (ADV) and entecavir (ETV) rescue therapy for patients with lamivudine (LAM)-resistant chronic hepatitis B (CHB). We aimed to compare the cumulative efficacy and resistance of ETV 1.0 mg monotherapy, ADV monotherapy and ADV add-on LAM combination therapy in LAM-refractory patients.
  
  
  METHODS
  One hundred and four patients were included in the following three treatment groups; group 1 (n = 24), LAM was switched to ETV (1.0 mg once a day); group 2 (n = 44), LAM was switched to ADV (10 mg once a day); and group 3 (n = 36), ADV was added to LAM (10 mg once a day).
  
  
  RESULTS
  After 6 months of rescue treatment, alanine aminotransferase normalization was observed in 75.0%, 65.9% and 74.3% of patients receiving ETV monotherapy, ADV monotherapy and ADV add-on therapy, respectively. A significantly higher log(10)HBV-DNA drop at 6 months occurred in the ADV add-on group compared with the ETV group. The rate of HBV-DNA polymerase chain reaction undetectability (<300 copies/mL) 6 months after initiation of ETV monotherapy, ADV monotherapy and ADV add-on therapy was 33.3%, 27.3% and 68.6%, respectively (P = 0.003). The cumulative HBeAg seroconversion rate was significantly higher in ADV add-on/ADV monotherapy groups compared with the ETV monotherapy group (P = 0.022). Viral breakthrough and genotypic resistance were detected in six (25.0%) and six (13.6%) patients in the ETV and ADV monotherapy groups, whereas no cases of genotypic resistance were detected in ADV add-on group 24 months after initiation of antiviral treatment (P < 0.01).
  
  
  CONCLUSIONS
  Adefovir add-on treatment in patients with LAM-resistant CHB suppresses HBV replication more effectively than ETV or ADV monotherapy. Additionally, no genotypic resistance was detected in the ADV add-on group.
authors.affiliation: Department of Internal Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University, Jongro-Ku, Seoul, Korea. hongjoo3.kim@samsung.com
authors.forename: Hong Joo
authors.initials: HJ
authors.lastname: Kim
authors.forename: Jung Ho
authors.initials: JH
authors.lastname: Park
authors.forename: Dong Il
authors.initials: DI
authors.lastname: Park
authors.forename: Yong Kyun
authors.initials: YK
authors.lastname: Cho
authors.forename: Chong Il
authors.initials: CI
authors.lastname: Sohn
authors.forename: Woo Kyu
authors.initials: WK
authors.lastname: Jeon
authors.forename: Byung Ik
authors.initials: BI
authors.lastname: Kim
mesh_terms: D000225:Adenine / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives*; D000328:Adult; D000410:Alanine Transaminase / Q000097:blood; D000998:Antiviral Agents / Q000008:administration & dosage* / Q000009:adverse effects; D015415:Biomarkers / Q000097:blood; D004279:DNA, Viral / Q000097:blood; D024882:Drug Resistance, Viral / Q000235:genetics; D004359:Drug Therapy, Combination; D005260:Female; D005838:Genotype; D006147:Guanine / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives*; D006513:Hepatitis B e Antigens / Q000097:blood; D006515:Hepatitis B virus / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development / Q000276:immunology; D019694:Hepatitis B, Chronic / Q000175:diagnosis / Q000188:drug therapy*; D006801:Humans; D019259:Lamivudine / Q000008:administration & dosage* / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D063065:Organophosphonates / Q000008:administration & dosage* / Q000009:adverse effects; D056910:Republic of Korea; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome; D019562:Viral Load; D014779:Virus Replication / Q000187:drug effects
chemical_list: D000998:Antiviral Agents; D015415:Biomarkers; D004279:DNA, Viral; D006513:Hepatitis B e Antigens; D063065:Organophosphonates; D019259:Lamivudine; C413685:entecavir; D006147:Guanine; C053001:adefovir; D000410:Alanine Transaminase; D000225:Adenine