1School of Medicine at University of California, San Diego, San Diego, CA, USA.
BACKGROUND & AIM:
Suboptimal viral suppression with adefovir (ADV) poses a challenge in managing chronic hepatitis B (CHB). Few studies have evaluated the efficacy of entecavir (ETV) in ADV-experienced patients. Our aim is to assess treatment effectiveness of ETV in ADV-experienced patients.
ADV-experienced patients switched to ETV were enrolled from six U.S. clinics. Patients completed a median of 24 months of ETV after switch. Patients were categorized into partial responders (detectable HBV DNA at switch) or complete responders (undetectable HBV DNA at switch) to ADV. Primary and secondary outcome measurements were complete viral suppression (CVS, HBV DNA <60 IU/mL) and biochemical response (BR, ALT < 40 U/L), respectively.
A total of 120 patients were included in the analysis (80 ADV partial responders; 40 ADV complete responders). In partial responders, CVS rate was 84% after 24 months of ETV. BR rate was 58% at switch to ETV and increased to 90% after 24 months. All complete responders continued to experience CVS after switch. On multivariate analysis inclusive of age, male gender, ALT level at switch, and history of lamivudine (LAM) exposure, we identified positive HBeAg status before ADV and higher HBV DNA level at time of switch as significant independent negative predictors of CVS. In eight patients with ADV-resistance, seven achieved CVS after 24 months of ETV and all achieved BR.
In ADV-experienced patients, high rates of CVS and BR can be achieved/sustained after switching to ETV, including those with ADV resistance or with prior exposure to LAM.