Study to Evaluate the Antiviral Activity, Clinical Outcomes, Safety, Tolerability, and Pharmacokinetics of Orally Administered Lumicitabine Regimens in Adult Participants Hospitalized With Respiratory Syncytial Virus

An AE is any untoward medical occurrence in a clinical study participant administered a medicinal (investigational or non-investigational) product. An AE does not necessarily have a causal relationship with the treatment. An AE can therefore be any unfavorable and unintended sign (including an abnormal finding), symptom, or disease temporally associated with the use of a medicinal (investigational or non-investigational) product, whether or not related to that medicinal (investigational or non-investigational) product.

Number of participants with vital sign (systolic and diastolic blood pressure [BP], pulse rate, respiratory rate, temperature and oxygen saturation) abnormalities were reported. For systolic BP: abnormally low refers to less than or equal to (<=) 90 millimeter of mercury (mmHg); for diastolic BP: abnormally low refers to <= 50 mmHg; for pulse rate abnormally low refers to less than (<) 45 beats per minutes (bpm) and abnormally high refers to greater than or equal to (>=) 120 bpm; for temperature in degree Celsius abnormally high refers to greater than (>) 37.8 (tympanic), >38.0 (forehead), >38.0 (oral), >37.2 (rectal), >38.0 (axillary); for oxygen saturation in percentage (%) abnormally low refers to < 95. Grade 1 = mild; grade 2 = moderate; grade 3 = severe.

Number of participants with QT interval abnormalities (prolonged) were reported.

Number of participants with clinical laboratory (serum chemistry and hematology) abnormalities were reported. Abbreviations; Erythrocyte MCHC = Erythrocyte Mean Corpuscular Hemoglobin Concentration; Erythrocyte MCH = Erythrocyte Mean Corpuscular Hemoglobin; Ery. = Erythrocyte

It is the time from treatment initiation to hospital discharge in hours.

It is the time from hospital admission to hospital discharge in hours.

It is the time from study treatment initiation to readiness for discharge in hours, with readiness for discharge defined by the investigator.

It is the time from hospital admission to readiness for discharge in hours, with readiness for discharge defined by the investigator.

Number of participants who required to be admitted to the ICU since initiation of treatment were reported.

In the event that a participant required ICU since initiation of treatment, the duration for how long the participant remained in the ICU was measured.

Number of participants who required supplemental oxygen were reported.

It is the time from first dose of study drug to the last end date and time of any oxygen supplementation in hours.

Time (number of hours) until SpO2 >= 93% on room air among participants who were not on supplemental oxygen prior to the onset of respiratory symptoms was reported.

It is the time from first dose of study drug until the time to return to pre-RSV disease level for respiratory rate. The return to pre-RSV disease level occurred when the observed value of the parameter was indicated by the investigator as normal, and no later observed values were indicated by the investigator as abnormal.

It is the time from first dose of study drug until the time to return to pre-RSV disease level for oxygen saturation. The return to pre-RSV disease level occurred when the observed value of the parameter was indicated by the investigator as normal, and no later observed values were indicated by the investigator as abnormal.

It is the time from first dose of study drug until the time to return to pre-RSV disease level for body temperature. The return to pre-RSV disease level occurred when the observed value of the parameter was indicated by the investigator as normal, and no later observed values were indicated by the investigator as abnormal.

Number of participants who required noninvasive mechanical ventilation support (that is supplemental oxygen [excluding mechanical ventilation]) were reported.

It is the time from first dose of study drug to the last end date and time of noninvasive mechanical ventilation support in hours.

Number of participants who required invasive mechanical ventilation support were reported.

It is the time from first dose of study drug to the last end date and time of invasive mechanical ventilation support in hours.

It is the time from first dose of study drug until the time to return to pre-RSV functional status. Functional status is the total points on the KATZ index of independence in activities of daily living (KATZ ADL score). Katz activities of daily living assessed questions related to bathing, dressing, toileting, transferring, continence and feeding components. Total score was calculated by adding the scores for all 6 activities which ranges from 0 high (participant independent) to 6 low (participant very dependent). If one or more component was missing, then the KATZ ADL score was not calculated. The return to pre-RSV functional status occurs at the timepoint where for the first time the KATZ ADL score is equal or higher than the pre-RSV KATZ ADL score and after which no scores lower than the pre-RSV KATZ ADL score occur anymore.

Number of participants who required hydration or feeding by IV catheter or nasogastric tube were reported.

Time to clinical stability is defined as the time from first dose of study drug until the time at which the following criteria were all met: normalization of blood oxygen level (return to baseline; by pulse oximetry) without requirement of supplemental oxygen beyond baseline level, normalization of oral feeding, normalization of respiratory rate and normalization of heart rate.

Number of participants in each ordinal scale category were reported. Ordinal scale consists of 6 categories or clinical states that are exhaustive, mutually exclusive, and ordered: category 1) death; category 2) admitted to ICU; category 3) non-ICU hospitalization requiring supplemental oxygen; category 4) non-ICU hospitalization not requiring supplemental oxygen; category 5) not hospitalized, unable to resume normal activities; category 6) not hospitalized, resumption of normal activities.

All-cause mortality included all deaths of participants due to any cause.

Antiviral activity RSV RNA viral load was measured in mid-turbinate nasal swabs (obtained from non-intubated participants) or in mid-turbinate nasal swabs and endotracheal samples (obtained from intubated participants or via suction through tracheostomy or other sampling methods) using qRT-PCR performed at the central laboratory.

Peak Viral load is the highest value of log10 viral load at or after the baseline measurement. Peak viral load over time was measured by qRT-PCR.

Time to peak viral load is the time from initiation of study treatment until the first time point with the peak viral load.

Rate of decline of viral load over the first 24 hours calculated as a log decline/24 hours defined as: 24-hour log viral load after first dose of study drug minus (-) log viral load at baseline divided by (/) date/time of 24-hour viral load sample - date/time of baseline viral load.

It is the time in hours from initiation of study treatment until the first post baseline time point at which the virus is undetectable in an assessment and after which time no detectable virus assessment follows as measured by qRT-PCR.

Number of participants with undetectable viral load up to 28 days were reported.

RSV RNA viral load was measured in midturbinate nasal swabs and in endotracheal samples (obtained from intubated participants or via suction through tracheostomy or other sampling.

RSV RNA viral load was measured in midturbinate nasal swabs and in endotracheal samples (obtained from intubated participants or via suction through tracheostomy or other sampling.

Number of participants with postbaseline changes in the RSV polymerase L gene and other regions of the RSV genome compared with baseline sequences were reported.