Ordinal scale categories include 7) Hospitalized, on Invasive Mechanical Ventilation or Extracorporeal Membrane Oxygenation (ECMO) and 8) Death. Mechanical ventilation-free survival was assessed through Day 29, defined as the proportion of participants who had not died nor were hospitalized on invasive mechanical ventilation or ECMO from Day 1 through Day 29. Estimates for the proportions are estimated from a logistic regression model adjusted for baseline dexamethasone, baseline ordinal score, age (continuous), and baseline CRP.

The primary subgroup population includes all randomized participants with a baseline ordinal score of 5 or 6, CRP<150 mg/L at baseline, and age<85 years.

Mechanical ventilation-free survival was assessed through Day 29, defined as the proportion of participants who had not died nor were hospitalized on invasive mechanical ventilation or ECMO from Day 1 through Day 29. Estimates for the proportions are estimated from a logistic regression model adjusted for baseline dexamethasone, baseline ordinal score, age (continuous), and baseline CRP.

The intention-to-treat (ITT) population includes all randomized participants.

Day of sustained recovery is defined as the first day on which the participant satisfies 1 of the following 3 categories from the clinical status ordinal scale (and does not return to a score of = 4 up to and including Study Day 60): 1) Not hospitalized, no new or increased limitations on activities; 2) Not hospitalized, but new or increased limitation on activities and/or requiring new or increased home oxygen, Continuous Positive Airway Pressure (CPAP), or Bilevel Positive Airway Pressure (BiPAP); 3) Hospitalized, not requiring new or increased supplemental oxygen - no longer requires ongoing medical care.

The primary subgroup population includes all randomized participants with a baseline ordinal score of 5 or 6, CRP<150 mg/L at baseline, and age<85 years.

Day of sustained recovery is defined as the first day on which the participant satisfies 1 of the following 3 categories from the clinical status ordinal scale (and does not return to a score of = 4 up to and including Study Day 60): 1) Not hospitalized, no new or increased limitations on activities; 2) Not hospitalized, but new or increased limitation on activities and/or requiring new or increased home oxygen, CPAP, or BiPAP; 3) Hospitalized, not requiring new or increased supplemental oxygen - no longer requires ongoing medical care.

The intention-to-treat (ITT) population includes all randomized participants.

The ordinal scale categories are defined as: 1) Not hospitalized, no new or increased limitations on activities; 2) Not hospitalized, but new or increased limitation on activities and/or requiring new or increased home oxygen, CPAP, or BiPAP; 3) Hospitalized, not requiring new or increased supplemental oxygen - no longer requires ongoing medical care; 4) Hospitalized, not requiring new or increased supplemental oxygen - requiring ongoing medical care (COVID-19 related or otherwise); 5) Hospitalized, requiring new or increased supplemental oxygen; 6) Hospitalized, requiring new or increased non-invasive ventilation or highflow oxygen devices; 7) Hospitalized, on invasive mechanical ventilation or extracorporeal membrane oxygenation (ECMO); 8) Death

The intention-to-treat (ITT) population includes all randomized participants.

Blood was collected at Days 1, 3, 5, 8, and 11 while participants were inpatient, and at Days 15 and 29, with the Day 1 assessment serving as baseline. Participants who had been discharged had blood collected if infection control measures allowed for in-person visits after discharge. Lower results are better, so a higher negative change from baseline indicates a more favorable outcome.

The safety population includes all randomized participants who received at least one dose of investigational product other than standard of care therapies with available data at baseline and post baseline assessment time point, analyzed as treated.

Blood was collected at Days 1, 3, 5, 8, and 11 while participants were inpatient, and at Days 15 and 29, with the Day 1 assessment serving as baseline. Participants who had been discharged had blood collected if infection control measures allowed for in-person visits after discharge. Lower results are better, so a higher negative change from baseline indicates a more favorable outcome.

The safety population includes all randomized participants who received at least one dose of investigational product other than standard of care therapies with available data at baseline and post baseline assessment time point, analyzed as treated.

Blood was collected at Days 1, 3, 5, 8, and 11 while participants were inpatient, and at Days 15 and 29, with the Day 1 assessment serving as baseline. Participants who had been discharged had blood collected if infection control measures allowed for in-person visits after discharge. Lower results are better, so a higher negative change from baseline indicates a more favorable outcome.

The safety population includes all randomized participants who received at least one dose of investigational product other than standard of care therapies with available data at baseline and post baseline assessment time point, analyzed as treated.

Blood was collected at Days 1, 3, 5, 8, and 11 while participants were inpatient, and at Days 15 and 29, with the Day 1 assessment serving as baseline. Participants who had been discharged had blood collected if infection control measures allowed for in-person visits after discharge. Higher results are better, so a higher positive change from baseline indicates a more favorable outcome.

The safety population includes all randomized participants who received at least one dose of investigational product other than standard of care therapies with available data at baseline and post baseline assessment time point, analyzed as treated.

Blood was collected at Days 1, 3, 5, 8, and 11 while participants were inpatient, and at Days 15 and 29, with the Day 1 assessment serving as baseline. Participants who had been discharged had blood collected if infection control measures allowed for in-person visits after discharge. Lower results are better, so a higher negative change from baseline indicates a more favorable outcome.

The safety population includes all randomized participants who received at least one dose of investigational product other than standard of care therapies with available data at baseline and post baseline assessment time point, analyzed as treated.

Blood to evaluate AST was collected at Days 1, 3, 5, 8, and 11 while participants were inpatient, and at Days 15 and 29, with the Day 1 assessment serving as baseline. Participants who had been discharged had blood collected if infection control measures allowed for in-person visits after discharge. Lower results are better, so a higher negative change from baseline indicates a more favorable outcome.

The safety population includes all randomized participants who received at least one dose of investigational product other than standard of care therapies with available data at baseline and post baseline assessment time point, analyzed as treated.

Blood was collected at Days 1, 3, 5, 8, and 11 while participants were inpatient, and at Days 15 and 29, with the Day 1 assessment serving as baseline. Participants who had been discharged had blood collected if infection control measures allowed for in-person visits after discharge. Lower results are better, so a higher negative change from baseline indicates a more favorable outcome.

The safety population includes all randomized participants who received at least one dose of investigational product other than standard of care therapies with available data at baseline and post baseline assessment time point, analyzed as treated.

Blood was collected at Days 1, 3, 5, 8, and 11 while participants were inpatient, and at Days 15 and 29, with the Day 1 assessment serving as baseline. Participants who had been discharged had blood collected if infection control measures allowed for in-person visits after discharge. Lower results are better, so a higher negative change from baseline indicates a more favorable outcome.

The safety population includes all randomized participants who received at least one dose of investigational product other than standard of care therapies with available data at baseline and post baseline assessment time point, analyzed as treated.

Blood was collected at Days 1, 3, 5, 8, and 11 while participants were inpatient, and at Days 15 and 29, with the Day 1 assessment serving as baseline. Participants who had been discharged had blood collected if infection control measures allowed for in-person visits after discharge. Higher results are better, so a higher positive change from baseline indicates a more favorable outcome.

The safety population includes all randomized participants who received at least one dose of investigational product other than standard of care therapies with available data at baseline and post baseline assessment time point, analyzed as treated.

Blood was collected at Days 1, 3, 5, 8, and 11 while participants were inpatient, and at Days 15 and 29, with the Day 1 assessment serving as baseline. Participants who had been discharged had blood collected if infection control measures allowed for in-person visits after discharge. Higher results are better, so a higher positive change from baseline indicates a more favorable outcome.

The safety population includes all randomized participants who received at least one dose of investigational product other than standard of care therapies with available data at baseline and post baseline assessment time point, analyzed as treated.

Blood was collected at Days 1, 3, 5, 8, and 11 while participants were inpatient, and at Days 15 and 29, with the Day 1 assessment serving as baseline. Participants who had been discharged had blood collected if infection control measures allowed for in-person visits after discharge. Lower results are better, so a higher negative change from baseline indicates a more favorable outcome.

The safety population includes all randomized participants who received at least one dose of investigational product other than standard of care therapies with available data at baseline and post baseline assessment time point, analyzed as treated.

Blood was collected at Days 1, 3, 5, 8, and 11 while participants were inpatient, and at Days 15 and 29, with the Day 1 assessment serving as baseline. Participants who had been discharged had blood collected if infection control measures allowed for in-person visits after discharge. Higher results are better, so a higher positive change from baseline indicates a more favorable outcome.

The safety population includes all randomized participants who received at least one dose of investigational product other than standard of care therapies with available data at baseline and post baseline assessment time point, analyzed as treated.

Blood was collected at Days 1, 3, 5, 8, and 11 while participants were inpatient, and at Days 15 and 29, with the Day 1 assessment serving as baseline. Participants who had been discharged had blood collected if infection control measures allowed for in-person visits after discharge. Higher results are better, so a higher positive change from baseline indicates a more favorable outcome.

The safety population includes all randomized participants who received at least one dose of investigational product other than standard of care therapies with available data at baseline and post baseline assessment time point, analyzed as treated.

Blood was collected at Days 1, 3, 5, 8, and 11 while participants were inpatient, and at Days 15 and 29, with the Day 1 assessment serving as baseline. Participants who had been discharged had blood collected if infection control measures allowed for in-person visits after discharge. Lower results are better, so a higher negative change from baseline indicates a more favorable outcome.

The safety population includes all randomized participants who received at least one dose of investigational product other than standard of care therapies with available data at baseline and post baseline assessment time point, analyzed as treated.

Blood was collected at Days 1, 3, 5, 8, and 11 while participants were inpatient, and at Days 15 and 29, with the Day 1 assessment serving as baseline. Participants who had been discharged had blood collected if infection control measures allowed for in-person visits after discharge. Lower results are better, so a higher negative change from baseline indicates a more favorable outcome.

The safety population includes all randomized participants who received at least one dose of investigational product other than standard of care therapies with available data at baseline and post baseline assessment time point, analyzed as treated.

Blood was collected at Days 1, 3, 5, 8, and 11 while participants were inpatient, and at Days 15 and 29, with the Day 1 assessment serving as baseline. Participants who had been discharged had blood collected if infection control measures allowed for in-person visits after discharge. Higher results are better, so a higher positive change from baseline indicates a more favorable outcome.

The safety population includes all randomized participants who received at least one dose of investigational product other than standard of care therapies with available data at baseline and post baseline assessment time point, analyzed as treated.

Blood was collected at Days 1, 3, 5, 8, and 11 while participants were inpatient, and at Days 15 and 29, with the Day 1 assessment serving as baseline. Participants who had been discharged had blood collected if infection control measures allowed for in-person visits after discharge. Lower results are better, so a higher negative change from baseline indicates a more favorable outcome.

The safety population includes all randomized participants who received at least one dose of investigational product other than standard of care therapies with available data at baseline and post baseline assessment time point, analyzed as treated.

Grade 3 AEs are defined as events that interrupt usual activities of daily living, or significantly affects clinical status, or may require intensive therapeutic intervention. Severe events are usually incapacitating. Grade 4 AEs are defined as events that are potentially life threatening while Grade 5 AEs are those that are fatal. Laboratory results were considered AEs if they were grade 3 or above according to the thresholds in the Division of AIDS (DAIDS) Table for Grading the Severity of Adverse Events.

The safety population includes all randomized participants who received at least one dose of investigational product other than standard of care therapies, analyzed as treated.

An SAE is defined as an AE or suspected adverse reaction that is considered serious if, in the view of either the investigator or the sponsor, it results in death, a life-threatening AE, inpatient hospitalization or prolongation of existing hospitalization, a persistent or significant incapacity or substantial disruption of the ability to conduct normal life functions, or a congenital anomaly/birth defect.

The safety population includes all randomized participants who received at least one dose of investigational product other than standard of care therapies, analyzed as treated.

Discontinuation or temporary suspension of study product is defined as any episode of early discontinuation or interruption of study product administration.

The safety population includes all randomized participants who received at least one dose of investigational product other than standard of care therapies, analyzed as treated.

Duration of hospitalization is defined first as the total number of days hospitalized for COVID-19, including readmissions for COVID-19-related reasons. It is also calculated as the total number of days hospitalized, including any readmissions for any reason.

The intention-to-treat (ITT) population includes all randomized participants.

Duration of invasive ventilation/ECMO was measured in days among participants who required invasive ventilation or died.

The intention-to-treat (ITT) population includes all randomized participants.

Duration of new invasive mechanical ventilation/ECMO use was measured in days among participants not on invasive ventilation/ECMO at baseline who progressed to invasive ventilation/ECMO or died.

The intention-to-treat (ITT) population includes all randomized participants. Only participants not on invasive ventilation/ECMO at baseline were included in the analysis.

Duration of non-invasive ventilation or high flow oxygen use was measured in days among participants who required non-invasive ventilation/high flow oxygen, invasive ventilation/ECMO or died.

The intention-to-treat (ITT) population includes all randomized participants.

Duration of new non-invasive ventilation or high flow oxygen use was measured in days among participants not on non-invasive ventilation/high flow oxygen at baseline who progressed to non-invasive ventilation/high flow oxygen, invasive ventilation/ECMO or died.

The intention-to-treat (mITT) population includes all randomized participants. Only participants in the 'hospitalized requiring new or increased supplemental oxygen ordinal scale' or better at baseline were included in the analysis.

Duration of supplemental oxygen use was measured in days among participants who required any supplemental oxygen, non-invasive ventilation/high flow oxygen, invasive ventilation/ECMO or died.

The intention-to-treat (mITT) population includes all randomized participants.

New Invasive Mechanical Ventilation / Extracorporeal Membrane Oxygenation (ECMO) Use is defined as participants not on invasive ventilation/ECMO at baseline who progressed to invasive ventilation/ECMO or died during the study.

The intention-to-treat (ITT) population includes all randomized participants. Only participants not on invasive ventilation/ECMO at baseline were included in the analysis.

New Non-invasive Ventilation/High Flow Oxygen Use is defined as participants in the hospitalized requiring new or increased supplemental oxygen ordinal scale or below at baseline who progressed to noninvasive ventilation/high flow oxygen, invasive ventilation/ECMO or died during the study.

The intention-to-treat (ITT) population includes all randomized participants. Only participants in the 'hospitalized requiring new or increased supplemental oxygen ordinal scale' or better at baseline were included in the analysis.

The ordinal scale categories are defined as: 1) Not hospitalized, no new or increased limitations on activities;2) Not hospitalized, but new or increased limitation on activities and/or requiring new or increased home oxygen, CPAP, or BiPAP; 3) Hospitalized, not requiring new or increased supplemental oxygen - no longer requires ongoing medical care; 4) Hospitalized, not requiring new or increased supplemental oxygen - requiring ongoing medical care (COVID-19 related or otherwise); 5) Hospitalized, requiring new or increased supplemental oxygen; 6) Hospitalized, requiring new or increased non-invasive ventilation or highflow oxygen devices; 7) Hospitalized, on invasive mechanical ventilation or extracorporeal membrane oxygenation (ECMO); 8) Death. A positive change indicates a worsening and a negative change is an improvement.

The intention-to-treat (ITT) population includes all randomized participants.

The mortality rate was determined as the proportion of participants who died by study Day 15. The proportions reported are Kaplan-Meier estimates.

The safety population includes all randomized participants who received at least one dose of investigational product other than standard of care therapies, classified by their actual treatment assignment.

The mortality rate was determined as the proportion of participants who died by study Day 29. The proportions reported are Kaplan-Meier estimates.

The safety population includes all randomized participants who received at least one dose of investigational product other than standard of care therapies, classified by their actual treatment assignment.

The mortality rate was determined as the proportion of participants who died by study Day 60. The proportions reported are Kaplan-Meier estimates.

The safety population includes all randomized participants who received at least one dose of investigational product other than standard of care therapies, classified by their actual treatment assignment.

Ordinal scale categories include 7) Hospitalized, on Invasive Mechanical Ventilation or Extracorporeal Membrane Oxygenation (ECMO) and 8) Death. Defined as the proportion of participants who were alive and were not hospitalized on invasive mechanical ventilation or ECMO at the Day 29 visit.

The intention-to-treat (ITT) population includes all randomized participants.

The ordinal scale is an assessment of the clinical status at the first assessment of a given study day. The scale is as follows: 1) Not hospitalized, no new or increased limitations on activities; 2) Not hospitalized, but new or increased limitation on activities and/or requiring new or increased home oxygen, CPAP, or BiPAP; 3) Hospitalized, not requiring new or increased supplemental oxygen - no longer requires ongoing medical care; 4) Hospitalized, not requiring new or increased supplemental oxygen - requiring ongoing medical care (COVID-19 related or otherwise); 5) Hospitalized, requiring new or increased supplemental oxygen; 6) Hospitalized, requiring new or increased noninvasive ventilation or high-flow oxygen devices; 7) Hospitalized, on invasive mechanical ventilation or extracorporeal membrane oxygenation (ECMO); 8) Death.

The intention-to-treat (ITT) population includes all randomized participants.

The ordinal scale is an assessment of the clinical status at the first assessment of a given study day. The scale is as follows: 1) Not hospitalized, no new or increased limitations on activities; 2) Not hospitalized, but new or increased limitation on activities and/or requiring new or increased home oxygen, CPAP, or BiPAP; 3) Hospitalized, not requiring new or increased supplemental oxygen - no longer requires ongoing medical care; 4) Hospitalized, not requiring new or increased supplemental oxygen - requiring ongoing medical care (COVID-19 related or otherwise); 5) Hospitalized, requiring new or increased supplemental oxygen; 6) Hospitalized, requiring new or increased noninvasive ventilation or high-flow oxygen devices; 7) Hospitalized, on invasive mechanical ventilation or extracorporeal membrane oxygenation (ECMO); 8) Death.

The intention-to-treat (ITT) population includes all randomized participants.

The time to death from study Day 1 to study Day 29, measured in days. The times reported are Kaplan-Meier estimates.

The safety population includes all randomized participants who received at least one dose of investigational product other than standard of care therapies, classified by their actual treatment assignment.