A Study to Compare Tenofovir DF Versus the Combination of Emtricitabine Plus Tenofovir DF for the Treatment of Chronic Hepatitis B in Patients With Normal Alanine Aminotransferase (ALT)

Study Summary

The main objective of the study was to evaluate the antiviral activity of tenofovir disoproxil fumarate (tenofovir DF) monotherapy versus emtricitabine (FTC) plus tenofovir DF combination therapy for the treatment of chronic hepatitis B (HBV) in participants in the immune tolerant phase of HBV infection. The efficacy of tenofovir DF monotherapy versus FTC plus tenofovir DF combination therapy was evaluated for suppression of the virus (decrease in HBV DNA), serological response (generation of antibodies to the virus), biochemical response (changes in liver enzymes), and the development of drug-resistant mutations. The safety and tolerability of both tenofovir DF monotherapy and FTC plus tenofovir DF were evaluated by routine monitoring for adverse events and changes in laboratory parameters. Participants were randomized in a 1:1 ratio to receive tenofovir DF monotherapy or FTC plus tenofovir DF. All subjects were to continue on blinded study medication until the last subject reached Week 192. Participants who permanently discontinued study drug (on or before Week 192) were followed for a 24-week treatment-free follow-up period, or until initiation of alternative HBV therapy, whichever occurred first. Subjects who discontinued study drug on or after Week 48 because of hepatitis B surface antigen (HBsAg) loss or seroconversion to antibody to hepatitis B surface antigen (anti-HBs), however, were to have returned for their regularly scheduled through Week 192 and every 16 weeks thereafter until the last subject reached Week 192.

Primary Outcome

The percentage of participants with HBV DNA \< 400 copies/mL at Week 192 was analyzed. Participants with missing data were considered to have failed to achieve the criteria for evaluation.

Interventions

• DRUG Placebo
• DRUG Tenofovir DF
• DRUG FTC