Safety and antiviral activity of emtricitabine (FTC) for the treatment of chronic hepatitis B infection: a two-year study

BACKGROUND/AIMS: The aim of this study was to evaluate long term safety and antiviral activity of different doses of emtricitabine given once daily to patients chronically infected with hepatitis B. METHODS: Eligible patients were randomized in a double-blind, parallel study to evaluate 25, 100 or 200 mg once daily doses of emtricitabine for 48 weeks. Patients were then followed for an additional 48 weeks on open-label 200 mg emtricitabine. Serum HBV DNA, ALT, and hepatitis B serology were measured at regular intervals over the 2 years. Resistance surveillance was performed after 1 and 2 years on viremic samples, i.e. > 4700 copies/mL. RESULTS: Emtricitabine was well tolerated and produced a dose proportional antiviral response. After 2 years, 53% of the patients had serum HBV DNA < or = 4700 copies/mL, 33% seroconverted to anti-HBe and 85% had normal ALT. Eighteen percent of the patients who had received 200 mg emtricitabine for 2 years developed resistance mutations. CONCLUSIONS: Emtricitabine was well tolerated and demonstrated a potent antiviral response for up to 2 years in patients with chronic hepatitis B infection. Based on these data, 200 mg emtricitabine once daily was chosen as the optimal dose for future hepatitis B studies.