Safety and Efficacy of Switching From Regimens Consisting of Boosted Atazanavir or Darunavir Plus Either Emtricitabine/Tenofovir or Abacavir/Lamivudine to Bictegravir/Emtricitabine/Tenofovir Alafenamide in Virologically Suppressed HIV-1 Infected Adults

Key Inclusion Criteria:

- Currently receiving a once daily antiretroviral regimen consisting of ritonavir or
cobicistat boosted ATV or DRV plus either FTC/TDF or ABC/3TC for ≥ 6 months preceding
the screening visit

- Adequate renal function:

- Estimated glomerular filtration rate ≥ 50 mL/min (≥ 0.83 mL/sec) according to the
Cockcroft-Gault formula

- Life expectancy ≥ 1 year

- Currently on a stable regimen for ≥ 6 months preceding the screening visit with
documented plasma HIV-1 RNA < 50 copies/mL for ≥ 6 months preceding the screening
visit (or undetectable HIV-1 RNA level according to the local assay being used if the
limit of detection is ≥ 50 copies/mL). Prior changes in antiretroviral regimen are
only allowed due to tolerability issues or for regimen simplification. Unconfirmed
virologic elevations of ≥ 50 copies/mL (transient detectable viremia, or "blip") prior
to screening are acceptable. (If the lower limit of detection of the local HIV-1 RNA
assay is < 50 copies/mL [e.g., < 20 copies/mL], the plasma HIV-1 RNA level cannot
exceed 50 copies/mL on two consecutive HIV-1 RNA tests)

- Have no documented or suspected resistance to FTC, tenofovir, ABC or 3TC, including
but not limited to the reverse transcriptase resistance mutations K65R and M184V/I

- No previous use of any approved or experimental integrase strand transfer inhibitor
(INSTI)

Key Exclusion Criteria:

- An opportunistic illness indicative of stage 3 HIV diagnosed within the 30 days prior
to screening

- Individuals experiencing decompensated cirrhosis (eg, ascites, encephalopathy, or
variceal bleeding)

- Have been treated with immunosuppressant therapies or chemotherapeutic agents within 3
months of study screening, or expected to receive these agents or systemic steroids
during the study (eg, corticosteroids, immunoglobulins, and other immune- or cytokine
based therapies)

- Current alcohol or substance use judged by the Investigator to potentially interfere
with subject study compliance

- A history of or ongoing malignancy (including untreated carcinoma in-situ) other than
cutaneous Kaposi's sarcoma (KS), basal cell carcinoma, or resected, non-invasive
cutaneous squamous carcinoma. Individuals with biopsy-confirmed cutaneous KS are
eligible, but must not have received any systemic therapy for KS within 30 days of Day
1 and are not anticipated to require systemic therapy during the study

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

- Participation in any other clinical trial, including observational studies, without
prior approval from the sponsor is prohibited while participating in this trial

- 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 the dosing requirements

- Any known allergies to the excipients of B/F/TAF FDC or ATV, RTV, DRV, COBI, FTC/TDF
or ABC/3TC

- Females who are pregnant (as confirmed by positive serum pregnancy test)

- Females who are breastfeeding

- Acute hepatitis in the 30 days prior to study entry

- Chronic hepatitis B infection in individuals not on a TDF containing regimen, as
determined by either:

- Positive hepatitis B virus (HBV) surface antigen and negative HBV surface
antibody, regardless of HBV core antibody status, at the screening visit

- Positive HBV core antibody and negative HBV surface antibody, regardless of HBV
surface antigen status, at the screening visit

- Active tuberculosis infection

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