Switching From TDF to TAF vs. Maintaining TDF in Chronic Hepatitis B With Resistance to Adefovir or Entecavir.

Exclusion Criteria

• •1. Co-infection with HCV, HDV, HIV
• •2. Abusing alcohol (more than 40 g/day) or illicit drugs
• •3. Abnormal hematological and biochemical parameters, including:
• •1\) serum bilirubin \>3 mg/dL 2) prothrombin time (INR) \>1.5 3) serum albumin \<2.8 g/dL 4) ascites, encephalopathy or variceal hemorrhage 5) Child-Pugh score ≥8
• •4\. Received interferon or other immunomodulatory treatment for HBV infection in the 12 months before screening for this study
• •5\. Medical condition that requires concurrent use of systemic corticosteroid or other immunosuppressive agent
• •6\. Received solid organ or bone marrow transplant
• •7\. Known hypersensitivity to study drugs, metabolites, or formulation excipients
• •8\. Any other clinical condition or prior therapy that, in the opinion of the Investigator, would make the patient unsuitable for the study or unable to comply with dosing requirements
• •9\. Use of investigational agents within 3 months of screening, unless allowed by the Sponsor or Investigator
• •10\. A history of hepatocellular carcinoma (HCC) within 5 years of screening
• •11\. A history treated malignancy (other than HCC) is allowable if the patient's malignancy has been in complete remission, off chemotherapy and without additional surgical intervention, during the preceding three years
• •12\. Participation in another investigational drug trial
• •13\. Pregnant or breastfeeding or willing to be pregnant