The efficacy of entecavir therapy in chronic hepatitis B patients with suboptimal response to adevofir

Background An increasing number of patients with chronic hepatitis B (CHB) have experienced treatment failure to adefovir (ADV) and their management poses a growing challenge. Very limited data are available on the efficacy of entecavir (ETV) in patients previously treated with ADV. Aim To examine the effect of ETV monotherapy on HBV DNA and ALT levels in CHB patients previously treated with ADV, but switched to ETV due to suboptimal response. Methods Study candidates were enrolled from five community gastroenterology clinics in the U. S. Each completed at least 12 months of ETV treatment after being previously treated with ADV and experiencing suboptimal response. Primary and secondary outcome measurements were complete viral suppression (CVS, HBV DNA <100 IU/mL) and biochemical response (BR, ALT <40 U/L), respectively. Results A total of 60 patients were included in this analysis. Twelve were lamivudine (LAM)-experienced and none were LAM-resistant. At time of switch to ETV, no patients had experienced CVS. The CVS rate was 68% after 12 months of ETV therapy. The BR rate was 67% at switch to ETV and 80% after 12 months. There was no significant difference in response rates between LAM-experienced and naive patients. Among the eight patients with ADV resistance, each achieved CVS after 12 months of ETV therapy and seven achieved BR. Conclusions In patients with suboptimal response to adefovir, complete viral suppression and biochemical response can be achieved in the majority by 12 months after switching to entecavir, including patients with prior exposure to lamivudine and those with adefovir resistance.