Key Inclusion Criteria:
Cohort 1 (treatment-experienced switch)
- Must not have a history of known resistance to elvitegravir (EVG), tenofovir disoproxil fumarate (TDF), or emtricitabine (FTC)
- Plasma HIV-1 RNA concentrations (at least two measurements) at undetectable levels (according to the local assay being used) in the 6 months preceding the screening visit and have HIV-1 RNA < 50 copies/mL at screening
- Estimated glomerular filtration rate (GFR) 30-69 mL/min according to the Cockcroft-Gault formula for creatinine clearance, using actual weight
- May be currently enrolled in Gilead studies GS-US-236-0102, GS-US-236-0103, and GS-US-216-0114, but will be eligible to enroll only after the Week 144 visit for that study is complete; or currently receiving Stribild® (STB) or atazanavir (ATV)/cobicistat (COBI) + Truvada (TVD) in Gilead studies GS-US-236-0104 or GS-US-216-0105, but will be eligible to enroll only after the Week 48 visit for that study is complete.
Cohort 2 (treatment-naive)
- Plasma HIV-1 RNA levels ≥ 1,000 copies/mL at screening
- Screening genotype report provided by Gilead Sciences must show sensitivity to EVG, FTC, and TDF
- 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
- Estimated GFR 30-69 mL/min according to the Cockcroft Gault formula for creatinine clearance, using actual weight
All Cohorts:
All individuals must meet all of the following inclusion criteria to be eligible for participation in this study:
- The ability to understand and sign a written informed consent form, which must be obtained prior to initiation of study procedures
- CD4+ count of ≥ 50 cells/μL
- Stable renal function: serum creatinine measurements to be taken at least once (within three months of screening)
- Cause of underlying chronic kidney disease (eg hypertension, diabetes) stable, without change in medical management, for 3 months prior to baseline
- Normal electrocardiogram (ECG)
- Hepatic transaminases (AST and ALT) ≤ 5 x upper limit of normal (ULN)
- Total bilirubin ≤ 1.5 mg/dL, or normal direct bilirubin
- Adequate hematologic function
- Serum amylase ≤ 5 x ULN
- Females of childbearing potential must agree to utilize highly effective contraception methods (two separate forms of contraception, one of which must be an effective barrier method, or be non-heterosexually active, 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
- Males must agree to utilize a highly effective method of contraception during heterosexual intercourse throughout the study period and for 30 days following discontinuation of investigational medicinal product. A highly effective method of contraception is defined as two separate forms of contraception, one of which must be an effective barrier method, or males must be non-heterosexually active, or practice sexual abstinence
Key Exclusion Criteria:
- A new AIDS-defining condition (excluding CD4 cell count and percentage criteria) diagnosed within the 30 days prior to screening,with the exception of the first two bullet points
- Hepatitis C virus (HCV) antibody positive. Individuals who are HCV positive, but have a documented negative HCV RNA, are eligible
- Hepatitis B surface antigen (HBVsAg) positive
- Individuals receiving drug treatment for Hepatitis C, or individuals who are anticipated to receive treatment for Hepatitis C during the course of the study
- Individuals experiencing decompensated cirrhosis (eg, ascites, encephalopathy, etc.)
- 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 or ongoing malignancy other than cutaneous Kaposi's sarcoma, 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 baseline
- Individuals on hemodialysis, other forms of renal replacement therapy, or on treatment for underlying kidney diseases (including prednisolone and dexamethasone)
- Individuals receiving ongoing therapy with any medications not to be used with EVG, COBI, FTC, or TAF or individuals with any known allergies to the excipients of E/C/F/TAF
Note: Other protocol defined Inclusion/Exclusion criteria may apply.