Efficacy and Safety of E/C/F/TAF (Genvoya®) in HIV-1/Hepatitis B Co-infected Adults

Key Inclusion Criteria:

- Both Cohorts 1 and 2:

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

- HIV/HBV co-infected adult males and non-pregnant and non-lactating females

- No evidence of hepatocellular carcinoma (HCC) or clinical or imaging evidence of
cirrhosis (ascites, variceal bleeding, encephalopathy).

--- Subjects should have documentation of an abdominal ultrasound in the 12
months prior to screening, or an abdominal ultrasound at screening, demonstrating
the absence of cirrhosis and HCC.

- Acute Hepatitis A virus (HAV) immunoglobulin M (IgM) negative

- Hepatitis C virus (HCV) Ab negative, or HCV Ab positive with negative HCV RNA

- Hepatitis D virus (HDV) Ab negative, or HDV Ab positive with negative HDV RNA

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

- CD4+ count of > 200 cells/μL

- Chronic HBV infection as defined by

- HBsAg positive for ≥ 6 months Or

- HBsAg positive at screening and either hepatitis B e antigen (HBeAg) or HBV
DNA positive ≥ 6 months Or

- At screening: positive total hepatitis B core antibody (HBcAb) and negative
immunoglobulin M antibody to hepatitis B core antigen (HBcIgM) antibody, and

- HBsAg positive, or

- HBeAg positive, or

- HBV DNA positive

- Cohort 1 (HIV and HBV treatment naive) only:

- No current or prior anti-HIV treatment, including antiretroviral medications
received for prevention (PrEP), or post exposure prophylaxis (PEP)

- No current or prior anti-HBV treatment

- Plasma HIV-1 RNA level ≥ 500 copies/mL at screening

- Screening HBV DNA ≥ 3 log10 IU/mL and < 9 log10 IU/mL

- Cohort 2 (HIV suppressed) only:

- Receiving current antiretroviral regimen for at least 4 consecutive months

- No current or prior regimen containing 3 active anti-HBV agents (i.e. cannot be
on tenofovir alafenamide (TDF)/emtricitabine (FTC)/Entecavir or
TDF/lamivudine(3TC)/Entecavir)

- Maintained plasma HIV-1 RNA < 50 copies/mL for 6 consecutive months prior to and
at the time of the screening visit. Unconfirmed virologic evaluation of ≥ 50
copies/mL after previously reaching viral suppression (transient detectable
viremia, or "blip") and prior to screening is acceptable

- Documented positive HIV antibody test

- Screening HBV DNA < 9 log10 IU/mL

Key Exclusion Criteria:

- Females who are breastfeeding

- Positive serum pregnancy test (female of childbearing potential)

- Have an implanted defibrillator or pacemaker

- Current alcohol or substance use

- 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 carcinoma.

- Received solid organ or bone marrow transplant

- Any history of, or current evidence of, clinical hepatic decompensation (e.g.,
ascites, encephalopathy or variceal hemorrhage).

- Significant bone disease (e.g., osteomalacia, chronic osteomyelitis, osteogenesis
imperfecta, osteochondroses), or multiple bone fractures

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

- Subjects on hemodialysis, other forms of renal replacement therapy, or on treatment
for underlying kidney diseases (including prednisolone, and dexamethasone)

- Any other clinical condition or prior therapy that, in the opinion of the
Investigator, would make the subject unsuitable for the study or unable to comply with
the dosing requirements

- Investigational agents (unless approved by Gilead Sciences). Participation in any
other clinical trial without prior approval from the sponsor is prohibited while
participating in this trial

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