Efficacy, Pharmacokinetics, and Safety of Presatovir in Hospitalized Adults With Respiratory Syncytial Virus (RSV) Infection

Key Inclusion Criteria: * Current inpatient * New onset of acute respiratory infectious symptoms, or acute worsening of chronic symptoms related to ongoing respiratory disease for ≤ 5 days prior to screening: * Upper respiratory tract symptoms: nasal congestion, runny nose, sore throat, or earache * Lower respiratory tract symptoms: cough, sputum production, wheezing, dyspnea, or chest tightness * Documented to be RSV-positive at the current admission within 72 hours of screening, or as evaluated at screening Key Exclusion Criteria: * Related to concomitant or previous medication use: * Use of oral prednisone or other corticosteroid equivalent to: * \> 20 mg/day for \> 14 days prior to screening is not permitted. * \> 20 mg/day for ≤ 14 days, including corticosteroids received during current hospitalization (ie, bolus doses), is permitted. * ≤ 20 mg/day, regardless of duration, is permitted. * Individuals taking a moderate or strong cytochrome P450 enzyme (CYP) inducer including but not limited to rifampin, St John's Wort, carbamazepine, phenytoin, efavirenz, bosentan, etracirine, modafinil, and nafcillin within 2 weeks prior to the first dose of study drug * Related to medical history: * Pregnant, breastfeeding, or lactating females * Individuals requiring \> 50% supplemental oxygen (while the individual is awake) at screening * Individuals with a Clinical Frailty Scale (CFS) \> 7 at Baseline * Known significant abnormality altering the anatomy of the nose or nasopharynx that in, the opinion of the investigator, will preclude obtaining adequate nasal swab sampling in either nasal passage * Waiting for or recently (within the past 12 months) received a bone marrow, stem cell, or solid organ transplant, or who have received radiation or chemotherapy within 12 months prior to Screening * Individuals with HIV/AIDS and a known CD4 count \< 200 cells/uL * History of severe dementia or Alzheimer's disease * History of drug and/or alcohol abuse that, in the opinion of the investigator, may prevent adherence to study activities * Related to medical condition at screening: * Influenza-positive as determined by local diagnostic test * Known Middle East Respiratory Syndrome coronavirus (MERS-CoV) infection or known coinfection with other coronavirus * Use of mechanical ventilation during the current admission, not including noninvasive ventilation * Clinically significant bacteremia or fungemia that has not been adequately treated prior to Screening, as determined by the investigator * Inadequate treatment of confirmed bacterial, fungal, or non-RSV pneumonia, as determined by the investigator * Excessive nausea/vomiting at admission, as determined by the investigator, that precludes administration of an orally administered study drug * Related to allergies: * Known allergy to components of the study drug (microcrystalline cellulose, mannitol, croscarmellose sodium, magnesium stearate, polyvinyl alcohol, titanium dioxide, polyethylene glycol and talc) * Documented history of acute (anaphylaxis) or delayed (Stevens-Johnson syndrome or epidermal necrolysis) allergy to sulfa drugs Note: Other protocol defined Inclusion/Exclusion criteria may apply.