Safety and Efficacy of GS-4774 in Combination With Tenofovir Disoproxil Fumarate (TDF) for the Treatment of Participants With Chronic Hepatitis B (CHB) and Who Are Currently Not on Treatment

A Phase 2, Randomized, Open-Label Study to Evaluate the Safety and Efficacy of GS-4774 in Combination With Tenofovir Disoproxil Fumarate (TDF) for the Treatment of Subjects With Chronic Hepatitis B and Who Are Currently Not on Treatment

The primary objectives of this study are to evaluate the safety, tolerability, and efficacy of GS-4774 in adults with CHB and who are currently not on treatment. Participants will be randomized to receive TDF alone or GS-4774 plus TDF for 20 weeks. After Week 20, GS-4774 will be discontinued. All participants will continue on TDF and will be followed for an additional 28 weeks. Following completion of the 48 week study period, all participants will be eligible for a treatment extension for 96 weeks.

Key Inclusion Criteria:

• Must have the ability to understand and sign a written informed consent form, which must be obtained prior to initiation of study
• Documented evidence of chronic hepatitis B virus (HBV) infection, for example, hepatitis B surface antigen (HBsAg) positive for more than 6 months
• Screening HBV DNA ≥ 2000 IU/mL
• A negative serum pregnancy test is required for females (unless surgically sterile or > 2 years post-menopausal)

Key Exclusion Criteria:

• Cirrhosis
• Inadequate liver function
• Co-infection with hepatitis C virus (HCV), HIV or hepatitis D virus (HDV)
• Received antiviral treatment for HBV within 3 months of screening
• Evidence of hepatocellular carcinoma (eg, as evidenced by recent imaging)
• Significant cardiovascular, pulmonary, or neurological disease
• Women who are pregnant or may wish to become pregnant during the course of the study
• Received solid organ or bone marrow transplant
• Received prolonged therapy with immunomodulators (eg, corticosteroids) or biologics (eg, monoclonal antibody, interferon) within 3 months of screening
• Use of investigational agents within 3 months of screening
• Current alcohol or substance abuse judged by the investigator to potentially interfere with individual's compliance
• Receipt of immunoglobulin or other blood products within 3 months prior to enrollment
• History of demyelinating disease (Guillain-Barre), Bell's Palsy, Crohn's disease, Ulcerative colitis, or autoimmune disease
• Documented history of yeast allergy
• Known hypersensitivity to study drugs, 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). Individuals under evaluation for possible malignancy are not eligible

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