['hiv-1 infection']
['ftc/tdf', 'f/taf', 'allowed third antiretroviral agent', 'ftc/tdf placebo', 'f/taf placebo']

        Key Inclusion Criteria:

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

          -  Currently receiving antiretroviral regimen containing FTC/TDF in combination with one
             third agent for ≥ 6 consecutive months prior to screening.

          -  Plasma HIV-1 RNA levels < 50 copies/mL for at least 6 months preceding the screening
             visit (measured at least twice using the same assay) and not experienced two
             consecutive HIV-1 RNA above detectable levels after achieving a confirmed (two
             consecutive) HIV-1 RNA below detectable levels on the current regimen in the past
             year.

          -  Plasma HIV-1 RNA should be < 50 copies/mL at the screening visit.

          -  Normal electrocardiogram (ECG)

          -  Estimated glomerular filtration rate (eGFR) ≥ 50 mL/min according to the
             Cockcroft-Gault formula for creatinine clearance

          -  Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤ 5 × the upper
             limit of the normal range (ULN)

          -  Total bilirubin ≤ 1.5 mg/dL, or normal direct bilirubin (individuals with documented
             Gilbert's syndrome or with Atazanavir-associated hyperbilirubinemia may have total
             bilirubin up to 5 x ULN)

          -  Adequate hematologic function

          -  Serum amylase ≤ 5 × ULN

          -  Females of childbearing potential must agree to utilize highly effective contraception
             methods or be non-heterosexually active, or practice abstinence from screening
             throughout the duration of the study treatment and for 30 days following the last dose
             of the study drug.

          -  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.

          -  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.

          -  Males must agree to utilize a highly effective method of contraception during
             heterosexual intercourse or be non-heterosexually active, or practice sexual
             abstinence from first dose throughout the study period and for 30 days following the
             last study drug dose.

        Key Exclusion Criteria:

          -  A new AIDS-defining condition diagnosed within the 30 days prior to screening

          -  Hepatitis C virus (HCV) antibody positive and HCV RNA detectable

          -  Individuals experiencing decompensated cirrhosis (e.g., ascites, encephalopathy, etc.)

          -  Individuals receiving ongoing treatment with bisphosphonate to treat bone disease (eg,
             osteoporosis)

          -  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

          -  A history of malignancy within the past 5 years (prior to screening) or ongoing
             malignancy other than cutaneous Kaposi's sarcoma (KS), basal cell carcinoma, or
             resected, non-invasive cutaneous squamous carcinoma.

          -  Active, serious infections (other than HIV-1 infection) requiring parenteral
             antibiotic or antifungal therapy within 30 days prior to Day 1 Visit

          -  Individuals receiving ongoing therapy with any of the medications not to be used with
             FTC, TAF, TDF or other antiretroviral third agents.

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