title: The efficacy of entecavir therapy in chronic hepatitis B patients with suboptimal response to adevofir.
abstract: BACKGROUND
  An increasing number of patients with chronic hepatitis B (CHB) have experienced treatment failure to adefovir (ADV) and their management poses a growing challenge. Very limited data are available on the efficacy of entecavir (ETV) in patients previously treated with ADV.
  
  
  OBJECTIVE
  To examine the effect of ETV monotherapy on HBV DNA and ALT levels in CHB patients previously treated with ADV, but switched to ETV due to suboptimal response.
  
  
  METHODS
  Study candidates were enrolled from five community gastroenterology clinics in the U.S. Each completed at least 12 months of ETV treatment after being previously treated with ADV and experiencing suboptimal response. Primary and secondary outcome measurements were complete viral suppression (CVS, HBV DNA <100 IU/mL) and biochemical response (BR, ALT < 40 U/L), respectively.
  
  
  RESULTS
  A total of 60 patients were included in this analysis. Twelve were lamivudine (LAM)-experienced and none were LAM-resistant. At time of switch to ETV, no patients had experienced CVS. The CVS rate was 68% after 12 months of ETV therapy. The BR rate was 67% at switch to ETV and 80% after 12 months. There was no significant difference in response rates between LAM-experienced and naïve patients. Among the eight patients with ADV resistance, each achieved CVS after 12 months of ETV therapy and seven achieved BR.
  
  
  CONCLUSIONS
  In patients with suboptimal response to adefovir, complete viral suppression and biochemical response can be achieved in the majority by 12 months after switching to entecavir, including patients with prior exposure to lamivudine and those with adefovir resistance.
authors.affiliation: Department of Medicine, Stanford University Medical Center, Stanford, CA, USA.
authors.forename: E
authors.initials: E
authors.lastname: Sheen
authors.forename: H N
authors.initials: HN
authors.lastname: Trinh
authors.forename: T T
authors.initials: TT
authors.lastname: Nguyen
authors.forename: S T
authors.initials: ST
authors.lastname: Do
authors.forename: P
authors.initials: P
authors.lastname: Tran
authors.forename: H A
authors.initials: HA
authors.lastname: Nguyen
authors.forename: K K
authors.initials: KK
authors.lastname: Nguyen
authors.forename: R T
authors.initials: RT
authors.lastname: Garcia
authors.forename: M H
authors.initials: MH
authors.lastname: Nguyen
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D000328:Adult; D000998:Antiviral Agents / Q000627:therapeutic use*; D024882:Drug Resistance, Viral / Q000187:drug effects*; D004359:Drug Therapy, Combination; D005260:Female; D005500:Follow-Up Studies; D006147:Guanine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D019694:Hepatitis B, Chronic / Q000188:drug therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D063065:Organophosphonates / Q000627:therapeutic use*; D012044:Regression Analysis; D013997:Time Factors; D016896:Treatment Outcome; D019562:Viral Load
chemical_list: D000998:Antiviral Agents; D063065:Organophosphonates; C413685:entecavir; D006147:Guanine; C053001:adefovir; D000225:Adenine