Study to Evaluate the Safety and Efficacy of E/C/F/TAF Versus E/C/F/TDF 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 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

   - Age ≥ 18 years

Key Exclusion Criteria:

   - A new 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

   - Receiving ongoing therapy with drugs not to be used with elvitegravir, cobicistat,
   emtricitabine, tenofovir DF, and TAF or participants with any known allergies to the
   excipients of E/C/F/TDF or E/C/F/TAF

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