title: Effect of switching to tenofovir with emtricitabine in patients with chronic hepatitis B failing to respond to an adefovir-containing regimen.
abstract: BACKGROUND
  In patients with chronic hepatitis B, long-term use of lamivudine is limited by resistance mutations. Adefovir dipivoxil has a very low rate of resistance, but there have been recent reports describing resistance mutations. Tenofovir disoproxil fumarate and emtricitabine show potent activity against wild-type and lamivudine-resistant hepatitis B virus.
  
  
  METHODS
  We describe a series of seven HIV-seronegative patients who failed to achieve undetectable hepatitis B viral DNA on adefovir. No lamivudine resistance testing was performed. The antiviral regimen was changed to tenofovir (300 mg daily) and emtricitabine (200 mg daily). Variables collected included levels of hepatitis B viral DNA by polymerase chain reaction, alanine and aspartate aminotransferase, hepatitis B e antigen and hepatitis B e antibody.
  
  
  RESULTS
  The median hepatitis B viral DNA level while on adefovir was 430,000 copies/ml with a median fall in hepatitis B viral DNA levels of 2.0 log10 copies/ml. Patients were on adefovir for a median period of 10 months before a change in regimen to tenofovir and emtricitabine. This regimen change resulted in a median fall in hepatitis B viral DNA levels of 3.0 log10 copies/ml (range, 2-4) after a median treatment duration of 23 months (range, 14-28). All patients (100%) had achieved undetectable hepatitis B viral DNA levels following combination therapy. Anti-hepatitis B e seroconversion occurred in one patient. No change in serum creatinine was observed during therapy, and no significant adverse events were reported.
  
  
  CONCLUSIONS
  In patients failing to respond to adefovir monotherapy or an adefovir-containing regimen for chronic hepatitis B virus, a combination of tenofovir and emtricitabine resulted in undetectable hepatitis B viral DNA levels without any renal toxicity. Tenofovir, in combination with emtricitabine, may be an alternative treatment for those with detectable hepatitis B viral DNA on adefovir.
authors.affiliation: Department of Medicine, Division of Liver Diseases, Mount Sinai School of Medicine, New York, New York 10029, USA.
authors.forename: Stephanie A
authors.initials: SA
authors.lastname: Santos
authors.forename: Alison J
authors.initials: AJ
authors.lastname: Uriel
authors.forename: James S
authors.initials: JS
authors.lastname: Park
authors.forename: Jennifer
authors.initials: J
authors.lastname: Lucas
authors.forename: Damaris
authors.initials: D
authors.lastname: Carriero
authors.forename: David
authors.initials: D
authors.lastname: Jaffe
authors.forename: Douglas T
authors.initials: DT
authors.lastname: Dieterich
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D000328:Adult; D000998:Antiviral Agents / Q000627:therapeutic use*; D004279:DNA, Viral / Q000097:blood; D003841:Deoxycytidine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D024882:Drug Resistance, Viral; D004359:Drug Therapy, Combination; D000068679:Emtricitabine; D005260:Female; D006515:Hepatitis B virus / Q000302:isolation & purification; D019694:Hepatitis B, Chronic / Q000188:drug therapy* / Q000821:virology; D006801:Humans; D008297:Male; D008875:Middle Aged; D063065:Organophosphonates / Q000627:therapeutic use*; D011446:Prospective Studies; D000068698:Tenofovir; D016896:Treatment Outcome
chemical_list: D000998:Antiviral Agents; D004279:DNA, Viral; D063065:Organophosphonates; D003841:Deoxycytidine; C053001:adefovir; D000068698:Tenofovir; D000068679:Emtricitabine; D000225:Adenine