Efficacy of entecavir switch therapy in chronic hepatitis B patients with incomplete virological response to telbivudine

Background: The roadmap concept suggests the use of ontreatment HBV DNA to guide treatment strategy of chronic hepatitis B patients treated by telbivudine. Our aim was to validate the roadmap approach of entecavir switch therapy in patients with incomplete response to telbivudine. Methods: Consecutive chronic hepatitis B patients on telbivudine monotherapy were studied. Incomplete virological response was defined as detectable HBV DNA after 6-12 months of treatment. Maintained virological response was defined as undetectable HBV DNA until the last follow-up. Results: Among the 79 patients on telbivudine, 39 (49%) had undetectable HBV DNA after 6-12 months of telbivudine treatment and 40 (51%) had incomplete virological response. In total, 33 incomplete responders switched to entecavir at 11 months (6-23), and 26 (79%) achieved maintained virological response after 25 months (4-46). Low HBV DNA level before switch therapy was the independent factor associated with maintained virological response to entecavir (P=0.01). A total of 24 of 25 (96%) patients with HBV DNA<2,000 IU/ml, versus 2 of 8 (25%) patients with HBV DNA >= 2,000 IU/ml, had maintained virological response after switching to entecavir. Although rtM204I and/or rtL180M was detected in 3 of 7 patients with incomplete virological response to entecavir, none of the patients with HBV DNA<2,000 IU/ml during telbivudine treatment harboured these amino acid substitutions. Conclusions: Roadmap approach using entecavir switch at month 6-12 among incomplete responders to telbivudine is recommended if the HBV DNA is <2,000 IU/ml at the time of switching.