Safety and Efficacy of GS-4774 for the Treatment of Chronic Hepatitis B

Inclusion Criteria:

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

- Currently taking an HBV oral antiviral medication

- Documented evidence of chronic HBV infection (eg, HBsAg positive for more than 6
months)

- Virally-suppressed (HBV DNA below the lower limit of quantification [LLOQ] by for ≥ 1
year)

Exclusion Criteria:

- Cirrhosis

- Inadequate liver function

- Co-infection with hepatitic C virus (HCV), HIV or hepatitic D virus (HDV)

- Evidence of hepatocellular carcinoma

- Significant cardiovascular, pulmonary, or neurological disease

- Females who are pregnant or may wish to become pregnant during the study

- Received solid organ or bone marrow transplant

- Use of another investigational agents within 3 months of screening

- Current alcohol or substance abuse judged by the investigator to potentially
interfere with compliance

- History of demyelinating disease (Guillain-Barre), Bell's Palsy, Crohn's disease
ulcerative colitis, autoimmune disease

- Known hypersensitivity to study drug, metabolites or formulation excipients

- Malignancy within 5 years prior to screening, with the exception of specific cancers
that are cured by surgical resection (basal cell skin cancer, etc). Participants
under evaluation for possible malignancy are not eligible.