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Entecavir (Baraclude) Less Effective for Patients with Multidrug-Resistant Hepatitis B


The nucleoside analog antiviral drug entecavir (Baraclude) was minimally effective against hepatitis B virus (HBV) that had already developed resistance to lamivudine (Epivir-HBV) and adefovir (Hepsera), researchers reported in the October 2011 Journal of Viral Hepatitis. Patient who achieved good early response, however, can do well if they stay on entecavir.

Korean researchers looked at the long-term outcome of switching to entecavir for chronic hepatitis B patients who had developed multidrug resistance after sequential therapy using lamivudine and adefovir.

The study included 33 patients with HBV infection who showed evidence of active viral replication (HBV DNA > 105 copies/mL) or a history of treatment failure with lamivudine/adefovir sequential therapy between April 2007 and July 2009. Participants were treated with 1.0 mg/day entecavir for at least 48 weeks and some for 96 weeks.


  • 66.7% of entecavir-treated patients experienced alanine aminotransferase (ALT) normalization at 48 weeks.
  • 24.2% achieved undetectable HBV DNA at 48 weeks.
  • Initial HBV viral load was the only factor significantly associated with undetectable HBV DNA after 48 weeks on entecavir, with lower viral load predicting better response.
  • At 96 weeks, 77.8% of participants experienced ALT normalization.
  • The proportion with undetectable viral load fell to 16.7% at 96 weeks.
  • 21.2% of patients experienced viral breakthrough by week 48, rising to 78.9% by week 96.
  • Participants who achieved HBV DNA < 4 log copies/mL at 48 weeks maintained similar viral load and normal ALT through 96 weeks.

Based on these findings, the researchers concluded, "Entecavir monotherapy for 96 weeks was not efficacious for patients with lamivudine/adefovir-resistant HBV. The initial HBV DNA level was the only predictive factor for antiviral efficacy."

However, they continued, "patients who achieved a HBV DNA level of < 4 log10 copies/mL with a normal ALT level at 48 weeks should maintain, rather than stop, entecavir therapy."

Investigator affiliations: Department of Internal Medicine, National Health Insurance Corporation Ilsan Hospital; Department of Internal Medicine, Ilsan Paik Hospital, Inje University College of Medicine, Goyang, Korea.



MS Kwak, JW Choi, JS Lee, et al. Long-term efficacy of entecavir therapy in chronic hepatitis B patients with antiviral resistance to lamivudine and adefovir. Journal of Viral Hepatitis 18(10): e432-e438 (abstract). October 2011.