Effectiveness of entecavir treatment and predictive factors for virologic response.

INTRODUCTION: Entecavir (ETV) is a potent inhibitor of hepatitis B virus (HBV) replication. In patients adherent to treatment, virologic remission rates of > 95 % can be maintained with entecavir at 3-5 years. AIM AND METHODS: A cohort study was performed, including all subjects who received ETV for chronic hepatitis B, in the South- Eastern Romania. We assessed viral response, HBeAg loss and seroconversion, HBsAg loss and seroconversion, biochemical response. Comparison of categorical data was performed by Chi2-test or Fisher´s exact where applicable.
RESULTS: Data from 533 patients were available: predominantly males (64 %), 82.6 % nucleotide naive, 23.1 % HBe-Ag positive, 78.2 % with elevated ALT, 8 % with cirrhosis. The median follow up was 24 months (range 12-48 months). Rate of undetectable HBV DNA increased constantly from year 1 to 3, reaching 91.2 %. Positive predictive factors for virologic response were low score of fibrosis (p-0.006), low level of HBV DNA (p-0.003), while negative predictive factors were: HBe antigen positive status (p-value < 0.001), prior IFN therapy (p 0.015). Virologic rebound was found in 7.8 % (breakthrough in 0.8 %). Rate of HBe Ag loss increases with the therapy duration, reaching 47.83 % in year 3,with two positive predictive factors: Male sex (p = 0.007), and undetectable HBV DNA at 24 weeks (p = 0.002). The percentage of HBs Ag loss was 1.31 %.
CONCLUSIONS: ETV maintained and even increased the high initial response rate (from 78 % to 91.2 %). Low score of fibrosis, low level of HBV DNA, HBe antigen negative status, absence of prior interferon therapy predict a good virologic response. Virologic rebound was found in a higher rate in our population, due probably to a poor drug compliance. Lamivudine-resistant patients usually respond well to ETV, but 15.62 % are non-responders, suspect of Entecavir resistance.