Study to Compare Tenofovir Alafenamide (TAF) Versus Tenofovir Disoproxil Fumarate (TDF) in Participants With Chronic Hepatitis B Infection Who Are Positive for Hepatitis B e Antigen

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.
* HBeAg-positive, chronic hepatitis B with all of the following:

* HBeAg-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 electrocardiogram (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, human immunodeficiency 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.