Virologic response and resistance to adefovir in patients with chronic hepatitis B

Scott K. Fung, Hee Bok Chae, Robert J. Fontana, Hari Conjeevaram, Jorge Marrero, Kelly Oberhelman, Munira Hussain, Anna S F Lok

Research output: Contribution to journalArticlepeer-review

301 Scopus citations


Background: The incidence and risk factors for adefovir-resistant HBV have not been clearly defined. Aims: To characterize the virologic response to adefovir, to determine the rate of adefovir resistance and to explore factors associated with initial virologic response (IVR) and adefovir resistance. Methods: All hepatitis B patients who received adefovir for ≥6 months at our center were prospectively monitored for virologic response and adefovir resistance. Results: Forty three patients were included; mean treatment duration was 18 months (range 6-45). Thirty four (79%) patients had prior lamivudine. IVR was observed in 44% patients and associated with higher pretreatment ALT (P=0.05) and the absence of HBeAg (P=0.02). Six (14%) patients were found to have adefovir-resistant mutations. The cumulative probability of genotypic resistance to adefovir at month 24 was 22%. Patients with adefovir resistance were more likely to have been switched from lamivudine to adefovir monotherapy (P=0.01), to be older (P=0.04), and to be infected with HBV genotype D (P=0.02). Conclusions: Roughly 50% of patients failed to achieve IVR on adefovir. The cumulative probability of adefovir resistance at 2 years was 22%. Our data suggest that combination of lamivudine and adefovir may prevent emergence of adefovir resistance in patients with lamivudine-resistant HBV.

Original languageEnglish (US)
Pages (from-to)283-290
Number of pages8
JournalJournal of Hepatology
Issue number2
StatePublished - Feb 2006


  • Adefovir
  • Antiviral resistance
  • Hepatitis B
  • Lamivudine

ASJC Scopus subject areas

  • Hepatology


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