A Phase 1 Study to Assess the Safety,Tolerability, and Pharmacokinetics of GS-6615 in Healthy Subjects

Inclusion Criteria: * Weight of at least 50 kg with body mass index (BMI) between 18 and 30 kg/m2 * Female subjects must be of non-childbearing potential as defined per the protocol * Male subjects with female partners of childbearing potential must be using protocol acceptable methods of contraception * Willing and able to comply with the requirements of the protocol and directions * Willing to avoid consumption of grapefruit, grapefruit juice and Seville oranges * Willing to avoid consumption of nicotine (including nicotine gum) and alcoholic beverages Exclusion Criteria: * Ongoing or history of any medical or surgical condition that, in the judgment of the Investigator, might jeopardize the subject's safety or interfere with the study objectives * History of meningitis or encephalitis, seizures, migraines, tremors, myoclonic jerks, sleep disorder, anxiety, syncope, head injuries or a family history of seizures * Any abnormal ECG findings, abnormal laboratory value, or physical examination findings at Screening judged to be clinically significant * Any abnormal neurological examination findings at Screening that is judged as clinically significant * Hemoglobin \< 12 g/dL * Serology test positive for HIV, or hepatitis B or C * Positive urine drug test (including cotinine or ethanol) * Use of systemic prescription medications or over the counter (OTC) medication, including multivitamins, and dietary and herbal supplement * Use of any experimental or investigational drug or device within 30 days * Female subjects who are of childbearing potential, pregnant or lactating * Donation or loss of blood within 8 weeks and/or donation of plasma within 7 days * History of drug or alcohol abuse * Psychosocial or addictive disorders