Tenofovir Alafenamide Versus Tenofovir Disoproxil Fumarate for Treatment of Hepatitis B e Antigen-Negative Hepatitis B

This study GS-US-320-0108 is an international study planned to enroll participants in global
countries, including China. However, due to the review timeline difference in China, full
enrollment was reached in the main study before China was able to participate. Therefore,
details for the China cohorts were registered separately (NCT02836236) on ClinicalTrials.gov
as these cohorts will not be part of the main study analysis.

Key Inclusion Criteria:

- Ability to understand and sign a written informed consent form, which must be obtained
prior to initiation of study procedures

- Adult males and non-pregnant, non-lactating females

- Documented evidence of chronic HBV infection

- Hepatitis e antigen (HBeAg)-negative, chronic hepatitis B with all of the following:

- HBeAg-negative and hepatitis B e antibody (HBeAb) positive at screening

- Screening HBV DNA ≥ 2 x 10^4 IU/mL

- Screening serum alanine aminotransferase (ALT) level > 60 U/L (males) or > 38 U/L
(females) and ≤ 10 x the upper limit of the normal range (ULN)

- Treatment-naive participants (defined as < 12 weeks of oral antiviral treatment with
any nucleoside or nucleotide analogue), OR treatment-experienced participants (defined
as participants meeting all entry criteria [including HBV DNA and serum ALT criteria]
and with ≥ 12 weeks of previous treatment with any nucleoside or nucleotide analogue)

- Previous treatment with interferon (pegylated or non pegylated) must have ended at
least 6 months prior to the baseline visit.

- Adequate renal function

- Normal ECG

Key Exclusion Criteria:

- Females 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, HIV, or hepatitis D virus

- Evidence of hepatocellular carcinoma

- Any history of, or current evidence of, clinical hepatic decompensation

- Abnormal hematological and biochemical parameters, including aspartate
aminotransferase (AST) > 10 x ULN

- Received solid organ or bone marrow transplant

- History of malignancy within the past 5 years, with the exception of specific cancers
that are cured by surgical resection; individuals under evaluation for possible
malignancy are not eligible

- Currently receiving therapy with immunomodulators (eg, corticosteroids),
investigational agents, nephrotoxic agents, or agents capable of modifying renal
excretion

- Individuals receiving ongoing therapy with drugs not to be used with tenofovir
alafenamide or tenofovir disoproxil fumarate 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 participant compliance

- Any other clinical condition or prior therapy that, in the opinion of the
Investigator, would make the participant unsuitable for the study or unable to comply
with dosing requirements

Note: Other protocol defined Inclusion/Exclusion criteria may apply.