Antiviral efficacy of lamivudine/adefovir combination therapy in chronic hepatitis b patients with resistance to lamivudine and adefovir consecutively

BACKGROUND/AIMS: The aim of this study was to elucidate the antiviral efficacy of lamivudine (LMV)-adefovir (ADV) combination therapy in chronic hepatitis B patients who showed resistance to LMV and ADV consecutively. METHODS: A retrospective review was performed in eighteen patients with chronic hepatitis B who developed virologic breakthroughs during LMV-ADV sequential mono-therapy and treated with LMV-ADV combination therapy. RESULTS: The median duration of follow up was 17 months (range, 6-27) after the start of LMV-ADV combination therapy. Mean HBV DNA level in log10 IU/mL was 6.08+/-0.95, 4.05+/-1.66, 3.17+/-1.58, 3.18+/-2.16, and 2.35+/-1.52 at 0, 3, 6, 12, and 24 months, respectively. Sixteen patients (88.9%) showed HBV DNA reduction below detection limit (<20,000 IU/mL). HBeAg seroconversion was observed in one patient (7.1%) after 8 months of combination therapy. Virologic breakthrough occurred in only one patient after 21 months of combination therapy. Viral rebound occurred in two patients at 12 months and 14 months of combination therapy. Normalization of serum ALT was achieved in twelve patients (66.7%). Primary non-response was observed in two cases (11.1%). CONCLUSIONS: LMV-ADV combination treatment was effective in 88.9% of patients with resistance to LMV and ADV in a short-term follow up. It may be applied as a bridge therapy until another effective antiviral regimen becomes available.