A Phase 1a Trial Assessing the Safety, Tolerability, and Immunogenicity of GS-4774 (GI-13020) at Various Dose Levels and Regimens in Healthy Adults

Inclusion Criteria: * Signed, written, informed consent from the subject before any study-specific procedures are performed * Free of obvious health problems as established by medical history and clinical examination before entering into the study * If female, negative pregnancy test and for women of childbearing potential willingness to use reliable method of birth control during the study and for 30 days after the last dose of study medication * Male or female aged ≥ 18 years at the time of first dose * Negative scratch test (immediate hypersensitivity, immunoglobulin E (IgE) mediated) to S. cerevisiae Exclusion Criteria: * Hospitalization in the last 6 months * No medicine adjustments in the last 6 months * History of anaphylaxis from any cause * History of hepatitis B virus (HBV) infection as evidenced by detection of HBV Surface and Core antigens * History of vaccination with HBV prophylactic vaccine or positive for antibody to HBV Surface and Core antigens * Known exposure to HBV within the past 6 weeks * Increased alpha fetoprotein (AFP) at screening * History of hepatitis C virus (HCV) infection or positive HCV antibody, Herpes zoster, shingles or any other chronic viral infection * Acute or chronic, clinically significant pulmonary, cardiovascular, hepatic or renal functional abnormality, as determined by physical examination or laboratory screening tests * Known history of HIV infection or positive HIV antibody test at screening * History of demyelinating disease such as Guillain-Barre Syndrome * History of Bell's Palsy * Immunosuppression as a result of underlying illness or treatment * History of cancer within the last 5 years with the exception of localized basal or squamous cell carcinoma or Stage 1A cervical cancer * History of Crohn's disease or ulcerative colitis * History of autoimmune disease * History of organ transplantation * Concurrent and chronic therapy with immunosuppressive drugs including systemic corticosteroids * Receipt of investigational drugs or vaccines within 30 days or 5 half lives, whichever is longer, prior to first injection with the study drug * Receipt of immunoglobulin or other blood products within 3 months prior to enrollment * Receipt of allergy shots within the preceding 7 days or expected to receive allergy shots during the study and 7 days following completion of study * Receipt of biologics * Negative histamine response on scratch test at screening * High risk for noncompliance with the protocol * Alcohol and/or IV drug abuse within the past year * Positive urine drug test at screen visit