Long-term Adefovir (Hepsera) plus Emtricitabine (Emtriva) vs Adefovir Monotherapy for Chronic Hepatitis B

Antiviral therapy with nucleoside/nucleotide analog agents is effective against chronic hepatitis B virus (HBV) infection, but long-term efficacy is limited by the emergence of drug resistant virus. As reported in the May 2008 Journal of Hepatology, researchers from the University of Hong Kong conducted a trial to determine the efficacy of adefovir dipivoxil (Hepsera) plus emtricitabine (Emtriva) combination therapy in patients with chronic hepatitis B. Adefovir is currently approved for this indication; emtricitabine is approved for the treatment of HIV, but is still under investigation for HBV.

In this study, 30 previously untreated hepatitis B "e" antigen (HBeAg) positive patients were randomly assigned to either combination adefovir plus emtricitabine (n=14) or adefovir monotherapy (n=16) for 96 weeks. HBV DNA was measured by polymerase chain reaction. Treatment was stopped in those who achieved HBeAg seroconversion.

Results

At 96 weeks, the median decrease in HBV DNA was greater in the combination therapy group compared with the adefovir monotherapy group (5.30 vs 3.98 log10 copies/mL; P = 0.05).

• More patients in the combination therapy group achieved alanine aminotransferase (ALT) normalization and HBV DNA < 300 copies/mL compared with the monotherapy group (78.6% vs 37.5%; P = 0.03).

• However, the rate of HBeAg seroconversion at week 96 was similar in the 2 groups (14.3% vs 25.0%; P = non-significant).

• No adefovir or emtricitabine resistance was detected at week 96.

• Among patients with HBeAg seroconversion, 50.0% experienced post-treatment relapse.

Based on these findings, the study authors concluded, "Combination [adefovir] plus [emtricitabine] resulted in more potent suppression of HBV DNA over 96 weeks of therapy."

4/18/08

Reference

C-K Hui, H-Y Zhang, S Bowden, and others. 96 weeks combination of adefovir dipivoxil plus emtricitabine vs. adefovir dipivoxil monotherapy in the treatment of chronic hepatitis B. Journal of Hepatology 48(5): 714-720. May 2008.