New data presented at the Annual Meeting of the American Association for the Study of Liver Diseases (AASLD) in Boston, 2nd to 6th November 2007,  showed that 91% of people with chronic hepatitis B treated with Baraclude® (entecavir) suppressed the amount of hepatitis B virus in their blood, or viral load, to undetectable levels for up to four years. Suppression of viral load to undetectable levels is a measure of antiviral treatment response; sustained viral load suppression is an important goal of chronic hepatitis B treatment.

Those enrolled in the study were e-antigen (HBeAg)-positive and had not previously been treated with an antiviral. HBeAg is a viral protein identified as a marker of active replication of the hepatitis B virus. They were initially treated with Baraclude 0.5 mg daily for two years, and then continued treatment after an interval of no more than 35 days with Baraclude 1 mg daily for up to four years.

Of the 108 people who had their viral load assessed at four years, 98 (91%) had undetectable levels.  Of the ten people who exhibited detectable levels of viral load, only one showed resistance to Baraclude. 

"This is particularly important data, given that the hepatitis B virus tends to develop resistance to many commonly-used anti-viral therapies over the long-term," said Mark Thursz, Professor of Hepatology, Faculty of Medicine, Imperial College London. "Baraclude has now been shown to prevent this occurrence for up to four years in the vast majority of hepatitis B patients."

Safety of Baraclude in this study was consistent with prior experience. Five deaths were reported, none of which were attributed to Baraclude. Twelve percent of people experienced what was classified as a serious adverse event.