Study to Evaluate the Safety and Efficacy of E/C/F/TAF (Genvoya®) Versus E/C/F/TDF (Stribild®) in HIV-1 Positive, Antiretroviral Treatment-Naive Adults

Key Inclusion Criteria:

* Ability to understand and sign a written informed consent form, which must be obtained prior to initiation of study procedures
* Plasma HIV-1 RNA levels ≥ 1,000 copies/mL at screening
* No prior use of any approved or investigational antiretroviral drug for any length of time, except the use for pre-exposure prophylaxis (PREP) or post-exposure prophylaxis (PEP), up to 6 months prior to screening
* Screening genotype report must show sensitivity to elvitegravir, emtricitabine, tenofovir disoproxil fumarate (tenofovir DF)
* Normal electrocardiogram (ECG)
* Estimated glomerular filtration rate (eGFR) ≥ 50 mL/min according to the Cockcroft-Gault formula for creatinine clearance
* Hepatic transaminases (AST and ALT) ≤ 5 × upper limit of normal (ULN)
* Total bilirubin ≤ 1.5 mg/dL, or normal direct bilirubin
* Adequate hematologic function
* Serum amylase ≤ 5 × ULN
* Males and females of childbearing potential must agree to utilize highly effective contraception methods or be non-heterosexually active or practice sexual abstinence from screening throughout the duration of study treatment and for 30 days following the last dose of study drug
* Females who utilize hormonal contraceptive as one of their birth control methods must have used the same method for at least three months prior to study dosing
* Females who have stopped menstruating for ≥ 12 months but do not have documentation of ovarian hormonal failure must have a serum follicle stimulating hormone (FSH) level at screening within the post-menopausal range based on the Central Laboratory reference range

Key Exclusion Criteria:

* A new acquired immunodeficiency syndrome (AIDS) defining condition diagnosed within the 30 days prior to screening
* Hepatitis B surface antigen (HBsAg) positive
* Hepatitis C antibody positive
* Individuals experiencing decompensated cirrhosis
* Females who are breastfeeding
* Positive serum pregnancy test
* Have an implanted defibrillator or pacemaker
* Current alcohol or substance use judged by the Investigator to potentially interfere with study compliance
* History of malignancy within the past 5 years or ongoing malignancy other than cutaneous Kaposi's sarcoma, basal cell carcinoma, or resected, noninvasive cutaneous squamous carcinoma
* Active, serious infections (other than HIV-1 infection) requiring parenteral antibiotic or antifungal therapy within 30 days prior to baseline
* 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
* Participation in any other clinical trial (including observational trials) without prior approval
* Individuals receiving ongoing therapy with drugs not to be used with elvitegravir, cobicistat, emtricitabine, tenofovir DF, and TAF or individuals with any known allergies to the excipients of E/C/F/TDF or E/C/F/TAF single-tablet regimen tablets

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