Study in Participants With Early Stage Coronavirus Disease 2019 (COVID-19) to Evaluate the Safety, Efficacy, and Pharmacokinetics of Remdesivir Administered by Inhalation

Time-weighted average change in SARS-CoV-2 viral load was defined as area under the concentration versus time curve (AUC) of viral load change divided by time between baseline through Day 7.

Time-weighted average change in SARS-CoV-2 viral load was defined as AUC of viral load change divided by time between baseline through Day 7.

Time-weighted average change in SARS-CoV-2 viral load was defined as AUC of viral load change divided by time between baseline through Day 7.

An adverse event (AE) was any untoward medical occurrence in a participant administered a study drug, which did not necessarily have a causal relationship with the treatment. AE was therefore any unfavorable and/or unintended sign, symptom, or disease temporally associated with the use of the study drug, whether or not considered related to the study drug. TEAEs: AE with an onset date on or after the study drug start date and no later than 30 days after study drug stop date; or any AE leading to study drug discontinuation.

Treatment-emergent laboratory abnormalities were graded using the Division of AIDS (DAIDS) Table for Grading the Severity of Adult and Pediatric Adverse Events, Version 2.1 July 2017. Laboratory abnormalities were graded as Grade 1 (mild), Grade 2 (moderate), Grade 3 (severe), Grade 4 (life-threatening). Percentage of participants with any severity grade were reported.

The composite outcome of all-cause MAVs (medical visits attended in person by the participant and a health care professional) or all-cause death by Study Day 28 were estimated using Kaplan-Meier methods by treatment group.

The composite outcome of COVID-19 related MAVs (medical visits attended in person by the participant and a health care professional) or all-cause death by Study Day 28 were estimated using Kaplan-Meier methods by treatment group.

The composite of all-cause hospitalization was estimated using Kaplan-Meier methods by treatment group.

AUC0-24h was defined as the concentration of drug over time between time 0 to time 24 hours. Time Frame for PK samples: Sparse PK (all participants): Day 1 (end of nebulization, and optional 2-hour post nebulization), and Day 3 (predose and end of nebulization); Intensive PK (Up to 6 participants/group in Part A & Part B): Day 1 and an additional sample at Day 3 or Day 5 at the following time points: 0 (predose), 0.25, 0.5, 0.75, 1, 1.5, 2, 4, and 24 hours post end of nebulization.

AUClast was defined as the concentration of drug from time zero to the last observable concentration.Time Frame for PK samples: Sparse PK (all participants): Day 1 (end of nebulization, and optional 2-hour post nebulization), and Day 3 (predose and end of nebulization); Intensive PK (Up to 6 participants/group in Part A & Part B): Day 1 and an additional sample at Day 3 or Day 5 at the following time points: 0 (predose), 0.25, 0.5, 0.75, 1, 1.5, 2, 4, and 24 hours post end of nebulization.

CLss/F was defined as apparent oral clearance at steady state after administration of the drug. CLss/F = Dose/AUCtau, where "Dose" is the dose of the drug. Time Frame for PK samples: Sparse PK (all participants): Day 1 (end of nebulization, and optional 2-hour post nebulization), and Day 3 (predose and end of nebulization); Intensive PK (Up to 6 participants/group in Part A & Part B): Day 1 and an additional sample at Day 3 or Day 5 at the following time points: 0 (predose), 0.25, 0.5, 0.75, 1, 1.5, 2, 4, and 24 hours post end of nebulization.

t1/2 was defined as the estimate of the terminal elimination half-life of the drug. Time Frame for PK samples: Sparse PK (all participants): Day 1 (end of nebulization, and optional 2-hour post nebulization), and Day 3 (predose and end of nebulization); Intensive PK (Up to 6 participants/group in Part A & Part B): Day 1 and an additional sample at Day 3 or Day 5 at the following time points: 0 (predose), 0.25, 0.5, 0.75, 1, 1.5, 2, 4, and 24 hours post end of nebulization.

Vz/F was defined as the apparent volume of distribution of the drug. Time Frame for PK samples: Sparse PK (all participants): Day 1 (end of nebulization, and optional 2-hour post nebulization), and Day 3 (predose and end of nebulization); Intensive PK (Up to 6 participants/group in Part A & Part B): Day 1 and an additional sample at Day 3 or Day 5 at the following time points: 0 (predose), 0.25, 0.5, 0.75, 1, 1.5, 2, 4, and 24 hours post end of nebulization.

Cmax was defined as the maximum observed concentration of drug.Time Frame for PK samples: Sparse PK (all participants): Day 1 (end of nebulization, and optional 2-hour post nebulization), and Day 3 (predose and end of nebulization); Intensive PK (Up to 6 participants/group in Part A & Part B): Day 1 and an additional sample at Day 3 or Day 5 at the following time points: 0 (predose), 0.25, 0.5, 0.75, 1, 1.5, 2, 4, and 24 hours post end of nebulization.

Tmax was defined as the time (observed time point) of Cmax. Time Frame for PK samples: Sparse PK (all participants): Day 1 (end of nebulization, and optional 2-hour post nebulization), and Day 3 (predose and end of nebulization); Intensive PK (Up to 6 participants/group in Part A & Part B): Day 1 and an additional sample at Day 3 or Day 5 at the following time points: 0 (predose), 0.25, 0.5, 0.75, 1, 1.5, 2, 4, and 24 hours post end of nebulization.

Clast was defined as the last observable concentration of drug. Time Frame for PK samples: Sparse PK (all participants): Day 1 (end of nebulization, and optional 2-hour post nebulization), and Day 3 (predose and end of nebulization); Intensive PK (Up to 6 participants/group in Part A & Part B): Day 1 and an additional sample at Day 3 or Day 5 at the following time points: 0 (predose), 0.25, 0.5, 0.75, 1, 1.5, 2, 4, and 24 hours post end of nebulization.

Tlast was defined as the time (observed time point) of Clast. Time Frame for PK samples: Sparse PK (all participants): Day 1 (end of nebulization, and optional 2-hour post nebulization), and Day 3 (predose and end of nebulization); Intensive PK (Up to 6 participants/group in Part A & Part B): Day 1 and an additional sample at Day 3 or Day 5 at the following time points: 0 (predose), 0.25, 0.5, 0.75, 1, 1.5, 2, 4, and 24 hours post end of nebulization.

AUCtau is defined as concentration of drug over time (the area under the concentration versus time curve over the dosing interval). Time Frame for PK samples: Sparse PK (all participants): Day 1 (end of nebulization, and optional 2-hour post nebulization), and Day 3 (predose and end of nebulization); Intensive PK (Up to 6 participants/group in Part A & Part B): Day 1 and an additional sample at Day 3 or Day 5 at the following time points: 0 (predose), 0.25, 0.5, 0.75, 1, 1.5, 2, 4, and 24 hours post end of nebulization.

λz was defined as the terminal elimination rate constant, estimated by linear regression of the terminal elimination phase of the log plasma concentration of drug versus time curve of the drug. Time Frame for PK samples: Sparse PK (all participants): Day 1 (end of nebulization, and optional 2-hour post nebulization), and Day 3 (predose and end of nebulization); Intensive PK (Up to 6 participants/group in Part A & Part B): Day 1 and an additional sample at Day 3 or Day 5 at the following time points: 0 (predose), 0.25, 0.5, 0.75, 1, 1.5, 2, 4, and 24 hours post end of nebulization.

Ctau was defined as the observed drug concentration at the end of the dosing interval. Time Frame for PK samples: Sparse PK (all participants): Day 1 (end of nebulization, and optional 2-hour post nebulization), and Day 3 (predose and end of nebulization); Intensive PK (Up to 6 participants/group in Part A & Part B): Day 1 and an additional sample at Day 3 or Day 5 at the following time points: 0 (predose), 0.25, 0.5, 0.75, 1, 1.5, 2, 4, and 24 hours post end of nebulization.

The time to negative nasopharyngeal SARS-CoV-2 PCR was defined as the number of days to first confirmed negative (first date of two consecutive dates achieving negative result) using nasopharyngeal sample. Time to negative nasopharyngeal SARS-CoV-2 PCR was calculated using Kaplan-Meier estimates.

The time to negative oropharyngeal SARS-CoV-2 PCR was defined as the number of days to first confirmed negative (first date of two consecutive dates achieving negative result) using an oropharyngeal sample. Time to negative oropharyngeal SARS-CoV-2 PCR was calculated using Kaplan-Meier estimates.

The time to saliva SARS-CoV-2 PCR was defined as the number of days to first confirmed negative (first date of two consecutive dates achieving negative result) using saliva sample. Time to negative saliva SARS-CoV-2 PCR was calculated using Kaplan-Meier estimates.

The InFLUenza Patient-Reported Outcome (FLU-PRO©) is a 32-item patient-reported outcome questionnaire that assesses the severity of symptoms of influenza and influenza-like illness across six body systems. An additional two items can be added to assess changes in taste or smell, if the instrument is used to quantify symptoms in studies of COVID-19. Each domain scores ranges from 0 (symptom-free) to 4 (very severe symptoms). Higher scores on this scale represent higher disease severity. Alleviation is defined as symptom scores as 2 or higher at baseline are scored as 0 (absent) or 1 (mild) at post-baseline, and symptoms scored as 1 at baseline are scored as 0 at post-baseline, and for two consecutive days. Time to alleviation was calculated using Kaplan-Meier estimates.