Study to Evaluate Efficacy and Safety of Switching From TDF to TAF in Adults With Chronic Hepatitis B Who Are Virologically Suppressed
Condition: Chronic Hepatitis B
MeSH terms: Hepatitis A; Hepatitis B; Hepatitis B, Chronic; Hepatitis; Hepatitis, Chronic
Intervention: TAF; TDF; TAF Placebo; TDF Placebo
Intervention description: 25 mg tablet administered orally once daily; 300 mg tablet administered orally once daily; Tablet administered orally once daily; Tablet administered orally once daily
Phase: Phase 3
Study type: Interventional
Primary purpose: Treatment
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Investigator)
Enrollment: 490.0
Sex: All
Minimum age: 18 Years
Healthy volunteers: No

Summary:

      The primary objectives of this study are to evaluate the efficacy, safety, and tolerability
      of switching to tenofovir alafenamide (TAF) versus continuing tenofovir disoproxil fumarate
      (TDF) in virologically suppressed adults with chronic hepatitis B virus (HBV) infection.
    

Eligibility criteria:

        Key Inclusion Criteria:

          -  Must have the ability to understand and sign a written informed consent form; consent
             must be obtained prior to initiation of study procedures

          -  Adult male and non-pregnant, non-lactating females

          -  Documented evidence of chronic hepatitis B virus (HBV) infection previously

          -  Maintained on tenofovir disoproxil fumarate (TDF) 300 mg once daily for at least 48
             weeks, and as monotherapy for chronic hepatitis B for at least 24 weeks with viral
             suppression (HBV DNA < lower limit of quantitation) for a minimum of 12 weeks prior to
             screening

          -  Adequate renal function

          -  Normal Electrocardiogram

        Key Exclusion Criteria:

          -  Pregnant women or women who are breastfeeding

          -  Males and females of reproductive potential who are unwilling to use an "effective",
             protocol-specified method(s) of contraception during the study.

          -  Co-infection with hepatitis C virus (HCV), hepatitis D virus (HDV), or human
             immunodeficiency virus (HIV)

          -  Evidence of hepatocellular carcinoma

          -  Current evidence of, or recent (≤ 5 year) history of clinical hepatic decompensation

          -  Abnormal hematological and biochemical parameters, including:

               -  Hemoglobin < 10 g/dL

               -  Absolute neutrophil count < 750/mm^3

               -  Platelets ≤ 50,000/mm^3

               -  Aspartate aminotransferase (AST) or alanine aminotransferase (ALT) > 5 × upper
                  limit of the normal (ULN)

               -  Albumin < 3.0 mg/ dL

               -  International normalized ratio (INR) > 1.5 × ULN (unless stable on anticoagulant
                  regimen)

               -  Total bilirubin > 2.5 × ULN

          -  Received solid organ or bone marrow transplant

          -  Malignancy within 5 years prior to screening, with the exception of specific cancers
             that are cured by surgical resection (eg, basal cell skin cancer). Individuals under
             evaluation for possible malignancy are not eligible.

          -  Currently receiving therapy with immunomodulators (eg, corticosteroids), nephrotoxic
             agents, or agents capable of modifying renal excretion

          -  Individuals receiving ongoing therapy with drugs not to be used with TAF or TDF or
             individuals with a known hypersensitivity to study drugs, metabolites, or formulation
             excipients

          -  Current alcohol or substance abuse judged by the investigator to potentially interfere
             with compliance

          -  Any other clinical condition or prior therapy that, in the opinion of the
             investigator, would make the individual unsuitable for the study or unable to comply
             with dosing requirements.

          -  Use of investigational agents within 3 months of screening, unless allowed by the
             sponsor

        Note: Other protocol defined Inclusion/Exclusion criteria may apply.