A Multi-centre, One-arm Prospective Study to Evaluate Efficacy and Safety of Switching From Entecavir (ETV) to Tenofovir Disoproxil Fumarate (TDF) in Japanese Chronic Hepatitis B HBeAg-positive and HBV-DNA Undetectable Subjects

Tenofovir Disoproxil Fumarate is a nucleos(t)ide analogue that inhibits Hepatitis B Virus
(HBV) growth, and is marketed in Japan with an indication for inhibition of HBV growth in
subjects with chronic hepatitis B associated with HBV growth and abnormal liver function.
This study has been planned to evaluate the virological effects and safety of switching from
ETV to TDF in chronic hepatitis B (hepatitis B e-antigen [HBeAg])-positive and HBV-
deoxyribonucleic acid (DNA) undetectable subjects. This study is designed as a multi-center,
one-arm, post-marketing clinical study to investigate the HBsAg reduction in subjects who
have not achieved the long-term goal, the loss of hepatitis B surface antigen (HBsAg). The
study will be conducted in HBeAg-positive and HBV-DNA undetectable subjects treated with ETV.
After switching ETV to TDF, TDF will be administered for 96 weeks. Approximately 80 subjects
will be screened to achieve 65 evaluable subjects.