Study of Acute Uncomplicated Seasonal Influenza A in Adult Subjects

Inclusion Criteria: Part A 1. Willing and able to comply with the NP swab procedure 2. Subject will sign and date an informed consent form (ICF) 3. Presenting to the clinic with symptoms suggestive of a diagnosis of acute influenza. Symptoms include oral temperature ≥38°C (100.4°F) within the prior 24 hours, at least 1 respiratory symptom AND at least 1 systemic symptom. 4. Understand that no study treatment will be provided to subjects in Part A but that they are free to receive any treatment considered appropriate by their physician Part B 1. Willing and able to comply with study requirements including treatment plan, study restrictions, laboratory tests, contraceptive guidelines, and other study procedures 2. Subject will sign and date an ICF 3. Present to the clinic with symptoms suggestive of a diagnosis of acute influenza. Symptoms include documented oral temperature ≥38°C (100.4°F) any time during the screening process, at least 1 respiratory symptom AND at least 1 systemic symptom, both scored as at least "moderate". 4. The time of onset of flu-like symptoms to the time anticipated for the start of treatment must be ≤48 hours. Onset of symptoms is defined as the first time (within 1 hour) the subject becomes aware of respiratory or systemic symptoms compatible with the flu or experiences an oral temperature ≥38°C (100.4°F) 5. Positive Rapid Influenza Diagnostic Test for influenza type A 6. Body mass index (BMI) of 18.0 to 33.0 kg/m2, inclusive, and a total body weight \>50 kg Exclusion Criteria: Part B 1. History of any illness or any clinical condition that, in the opinion of the investigator or the subject's general practitioner, might confound the results of the study or pose an additional risk in administering study drug(s) to the subject. 2. Any condition possibly affecting drug absorption (e.g., gastrectomy, cholecystectomy, or other gastrointestinal tract surgery, except appendectomy). 3. Immunized (intranasal or injected vaccine) against influenza in the 6 months before study entry. 4. At Screening, an ECG that is abnormal and deemed by the investigator(s) to be clinically significant. 5. For female subjects: Pregnant or nursing subjects and female subjects of childbearing potential who are unwilling or unable to use an acceptable method of contraception as outlined in this protocol. 6. For male subjects, unwilling to comply with contraception requirements as outlined in the study protocol. 7. Blood donation (of approximately 1 pint \[500 mL\] or more) within 56 days before the first study drug dose. 8. Use of the following medications: * Influenza antiviral medication (oseltamivir, zanamivir, rimantidine, or amantadine) within 14 days or ribavirin within 6 months of screening. * Substrates of OATP1B1 and/or OATP1B3, including atrasentan, bosentan, ezetimibe, glyburide, irinotecan, repaglinide, rifampin, telmisartan, valsartan, and olmesartan, from Day 1 through the last dose of study drug. "Statins" (i.e., HMG CoA reductase inhibitors) may be continued, but subjects should be cautioned and observed for potential "statin"-related toxicity. Alternatively, subjects can abstain from statins for the duration of study drug dosing. * Strong inhibitors or inducers of CYP3A metabolism, including carbamazepine, clarithromycin, HIV and HCV protease inhibitors, itraconazole, ketoconazole, nefazodone, phenytoin, posaconazole, rifampin, St. John's wort, telithromycin, and voriconazole from 2 weeks prior to the first dose of study drug until the last PK sample is collected on Day 8. * An investigational drug or device 30 days before the first dose of study drug, 5 half lives before the first dose of study drug, or time determined by local requirements, whichever is longest. 9. History of excessive alcohol consumption. 10. History of known or current usage of drugs of abuse. 11. Hospitalized subjects and subjects with bacterial infections requiring systemic antibacterial agents at the time of screening.