A Phase 1 Study of Novel GS-9973 Tablet Formulations to Evaluate the Effect of Acid Reducing Agents, Relative Bioavailability, and Food Effect on GS-9973 Pharmacokinetics

Inclusion Criteria:

Have the ability to understand and sign a written informed consent form, which must be obtained prior to initiation of study procedures
Must have a body mass index (BMI) range of approximately 19 to 30 kg/m2
Must have a minimum weight of 45 kg

Females of childbearing potential must have negative serum pregnancy tests at screening and baseline and must practice at least 1 reliable method of contraception as defined by the protocol

Female subjects who utilize hormonal contraceptive as 1 of their birth control methods must have used the same method for at least 3 months prior to study dosing
Male subjects must agree to use condoms during heterosexual intercourse and avoid sperm donation from Day -1 until 90 days following the last dose of study medication
Must refrain from blood donation throughout the study period
Must, in the opinion of the Investigator, be in good general
Must be a non- or light smoker, eg, less than 10 cigarettes per day

Exclusion Criteria:

Pregnant or lactating subjects
Use of prescribed or over-the-counter medications that affect gastric pH
History of severe peptic ulcer disease, GERD, or other diseases requiring prolonged(>6 weeks) medication or surgical therapy to modify gastric pH
Have a history of clinically significant cardiac abnormalities or presence of clinically significant abnormality on 12-lead ECG.
Have a history of any cancer requiring systemic chemotherapy or radiation
Have a history of bleeding disorders
Have a history of liver disorders
Current acute infection or history of acute infection within 7 days
Have a recent history of alcohol or illicit drug abuse and/or have a positive test for selected drugs of abuse
Have a positive hepatitis screen or positive Human Immunodeficiency Virus antibody test
Have participated in another clinical trial within 28 days
Have received transfusion of blood or plasma products within 6 months
Have donated > 500 mL blood within 56 days
Are unable or unwilling to comply with study restrictions, return for follow-up appointments, or other considerations, which in the opinion of the Investigator, would make the candidate unsuitable for study participation
Current or historical medical condition that is deemed to be of medical significance by the Investigator
Have used prescription medications, over the counter products, herbal remedies and nutritional supplements within 7 days