Source Hepatology Section, Department of Medicine, Centro de Educación Médica e Investigaciones Clínicas Norberto Quirno 'CEMIC', Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina Centro de Hepatología, La Plata. Prov. de Buenos Aires, Buenos Aires, Argentina Liver Unit, Hospital Provincial del Centenario/Sanatorio Americano, Rosario, Prov. de Santa Fe, Argentina Liver Unit, Hospital Universitario Austral. Pilar. Prov. de Buenos Aires, Buenos Aires, Argentina Liver Unit, Hospital Francisco J. Muñiz. Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina.

Introduction:  Registration studies showed entecavir (ETV) to be effective and safe in NUC-naïve patients with chronic hepatitis B virus (HBV), but its effectiveness in routine clinical practice is unknown.

Materials and methods:  Sixty-nine HBeAg positive and negative NUC naïve chronic HBV patients were treated with ETV for 110 weeks. 63% were HBeAg positive, 16% were cirrhotics, mean HBV-DNA was 7.09 log IU/ml and mean ALT was 157 IU/ml.

Results:  Sixty-one (88%) patients achieved undetectable DNA, with 46%, 77% and 100% virological response rates at week 24, 48 and 96 of treatment, respectively. Thirty-seven (84%) patients in the HBeAg-positive population achieved undetectable DNA, with 67% and 100% virological response rates at week 48 and 96 of treatment, respectively. Twenty-four (96%) patients in the HBeAg-negative population achieved undetectable DNA, with 91% and 100% virological response rates at week 48 and 96 of treatment, respectively. Twenty-three (53%) patients cleared HBeAg and 19 (44%) patients seroconverted to antiHBe positive status; seven (10%) patients cleared hepatitis B surface antigen and five (7%) patients developed antiHBs. At the end of the study, 10 patients successfully stopped therapy: nine HBeAg positive (four developed antiHBs positive) and one HBeAg negative. None of the patients had primary non-response. ETV resistance was not tested. None of the patients developed hepatocellular carcinoma, underwent liver transplantation or died because of liver-related events. No serious adverse events were reported.

Conclusion:  The ETV monotherapy showed high virological response rates, a favourable safety profile for NUC-naive HBeAg-positive and negative patients treated in routine clinical practice.