Eleven patients with chronic HBV infection (8 HBeAg positive), and persistent viral replication after a mean of 24 months of Adefovir (ADV) monotherapy (range 9–42 months) were switched to Entecavir (ETV) monotherapy either with 0.5 or 1mg daily and retrospectively analyzed for changes in HBV viral load (log10 IU/ml). Mean exposure to ETV was 11.5 months (range 4–24 months). Differences were checked for significance using student’s t-test.
The average viral load during the preceding 21 months of ADV therapy was 3.98 (±1.63) log10, the average viral load after switching to ETV was 2.24 (±1.59) log10, thus resulting in an average decline of 1.75 (±1.95) log10 (p=0.014). The average viral load at the time of switching to ETV was 4.84 (±1.40) log10, which declined subsequently to 1.83 (±1.72) log10 with an average decline between switch and end of current follow-up of 3.01 (±1.90) log10 (p=0.0004). The average log10 decline 6 months after switching to ETV (n=10) was 2.14 (±1.54) log10 (p=0.001).
The viral load of 9/11 patients declined to below 10.000 copies/ml (3.3 log10) after a mean treatment period with ETV of 11.5 months, while 7/11 patients were below this viral load level already 6 months after switching to ETV. The viral load of 5/11 patients declined to below 300 copies (1.8 log10) under ETV therapy, with 1/11 patients showing a viral load below 300 copies after 6 months under ETV treatment (1/11 HBV DNA negative). 4/11 patients showed a further decline to undetectable HBV-DNA levels under continuing ETV therapy.
Conclusion:
In this retrospective analysis switching to ETV in incomplete responders to ADV monotherapy resulted in a significant further decline of HBV DNA viral load of 3.01 log10 IU/ml with 4/11 patients showing undetectable HBV DNA levels after a mean treatment time of 11.5 months. These data suggest that ETV may present a useful salvage therapy for chronic HBV patients with an incomplete response to ADV therapy.
Adefovir - Entecavir - Hepatitis B - switching
