After randomization into the study, subjects will then be eligible to enroll into a separate extension study to receive treatment with tenofovir for up to 52 weeks. In this Extension Period, subjects will return to the clinic for standard of care (SOC) visits every 3 months with laboratory tests of liver function and virological efficacy including HBsAg, HBeAg, HBeAb and HBV DNA. No further study related testing will be performed.