OBJECTIVETo evaluate the antiviral activity and safety of entecavir in patients with chronic HBV infection as a preliminarily step in selecting 0.1 mg or 0.5 mg as a better dosage for a further large scale clinical trial.

METHODSThis was a randomized, double-blinded, placebo-controlled and dose-ranging trial of entecavir usage in 212 patients with chronic HBV infection. The patients were randomly assigned to 3 groups: 0.1 mg entecavir (69), 0.5 mg entecavir (72) and, placebo (71) groups and treated for 28 days. The patients were then followed for 56 days without treatment.

RESULTSThe proportion of subjects who achieved the primary endpoint at day 28, with their HBV DNA level decreased >2 log or undetectable, was significantly greater in the entecavir 0.1 mg and 0.5 mg dose groups compared with the placebo group (P < 0.01 for both comparisons). The mean change from baseline in HBV DNA levels at day 28 was greater for entecavir 0.1mg and 0.5 mg groups compared with the placebo group (both P < 0.01). The mean change from baseline in HBV DNA levels at day 28 for entecavir 0.5 mg group was greater than that of the entecavir 0.1 mg group (P < 0.01). During the 56-day post-dosing follow-up phase, the entecavir 0.5 mg group was associated with greater and more sustained suppression of viral replication than the entecavir 0.1 mg group (P < 0.01). There were no clinically meaningful differences in the incidence of any adverse events between the entecavir dosing and the placebo groups.

CONCLUSIONEntecavir at both 0.1 mg and 0.5 mg doses demonstrated superior antiviral activity compared with a placebo. Since the entecavir 0.5 mg dose appears to have greater antiviral activity than the 0.1 mg dose and with a comparable safety and tolerability profile, the 0.5 mg entecavir dose could be used in further trials.