title: Tenofovir rescue therapy in chronic hepatitis B patients who failed previous nucleoside analogue treatment.
abstract: BACKGROUND
  Tenofovir (TDF) is considered as the first line therapy for chronic hepatitis B. This study presents the results of TDF monotherapy in patients who failed previous nucleoside analogue treatment.
  
  
  METHODS
  The study included 29 patients treated with TDF 245 mg once daily for 18 months after lamivudine monotherapy (LAM arm: n = 15) or sequential therapy with lamivudine and entecavir (LAM → ETV arm: n = 14). The previous antiviral therapy was discontinued due to lack of efficacy. All patients had HBV DNA between 2.1 and 8.23 log10 IU/ml and 15 were HBeAg-positive, while 45% of patients had increased ALT activity. Undetectable HBV DNA (<20 IU/ml) at months 3, 6, 12 and 18 was the primary endpoint in the study, while HBeAg/HBsAg loss/seroconversion and ALT normalisation were secondary endpoints.
  
  
  RESULTS
  Primary nonresponse to TDF was not observed. HBV DNA was undetectable in 80, 80, 80 and 93% in LAM arm and 50, 71, 86 and 86% in LAM → ETV arm patients, at 3, 6, 12 and 18 months of TDF therapy, respectively. One patient achieved anti-HBeAg seroconversion. 86.5% of patients had normal ALT activity at the end of the study. The baseline HBV DNA load, HBeAg status and the length of the duration of TDF therapy appeared significantly associated with the response to the therapy. HBV DNA clearance occurred faster in HBeAg-negative patients than in those positive for HBeAg.
  
  
  CONCLUSIONS
  TDF is an effective antiviral medication in patients with previous exposure to LAM or LAM and ETV. Final proportion of patients who achieved undetectable HBV DNA and had normal ALT activity in both arms, was similar.
authors.affiliation: Department of Infectious Diseases and Hepatology, Faculty of Medicine, Nicolaus Copernicus University in Toruń, ul. Św. Floriana 12, 85 030, Bydgoszcz, Poland. d.kozielewicz@wsoz.pl.
authors.forename: Dorota
authors.initials: D
authors.lastname: Kozielewicz
authors.affiliation: Department of Infectious Diseases and Hepatology, Faculty of Medicine, Nicolaus Copernicus University in Toruń, ul. Św. Floriana 12, 85 030, Bydgoszcz, Poland. w.halota@wsoz.pl.
authors.forename: Waldemar
authors.initials: W
authors.lastname: Halota
authors.affiliation: Department of Theoretical Foundations of Biomedical Sciences and Medical Computer Science, Faculty of Pharmacy, Nicolaus Copernicus University in Toruń, ul Jagiellońska 13-15, 85 067, Bydgoszcz, Poland. mpiszcz@cm.umk.pl.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Wietlicka-Piszcz
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000998:Antiviral Agents / Q000008:administration & dosage*; D004279:DNA, Viral / Q000032:analysis; D004334:Drug Administration Schedule; D005260:Female; D006515:Hepatitis B virus / Q000235:genetics / Q000302:isolation & purification; D019694:Hepatitis B, Chronic / Q000188:drug therapy* / Q000821:virology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D000068698:Tenofovir / Q000008:administration & dosage*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000998:Antiviral Agents; D004279:DNA, Viral; D000068698:Tenofovir
keywords: Antiviral therapy; Chronic hepatitis B; Entecavir resistance; Lamivudine resistance; Tenofovir disoproxil fumarate