Safety, Tolerability, and Efficacy of Anti-Spike (S) SARS-CoV-2 Monoclonal Antibodies for Hospitalized Adult Patients With COVID-19

Study Overview
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Brief Summary
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The primary objectives are: Pooled Phase 3 (Cohort 1) and Phase 2 (Cohort 1A) To evaluate the virologic efficacy of REGN10933+REGN10987 compared to placebo in reducing viral load of SARS-CoV-2 To evaluate the clinical efficacy of REGN10933+REGN10987 compared to placebo, as measured by death or mechanical ventilation Phase 1/2 (Cohort 1) To exclude futility of REGN10933+REGN10987 compared to placebo, as measured by death or mechanical ventilation To evaluate the safety and tolerability of REGN10933+REGN10987 compared to placebo

Official Title
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A Master Protocol Assessing the Safety, Tolerability, and Efficacy of Anti-Spike (S) SARS-CoV-2 Monoclonal Antibodies for the Treatment of Hospitalized Patients With COVID-19

Conditions
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COVID-19

Intervention / Treatment
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* Drug: REGN10933+REGN10987 combination therapy
* Drug: Placebo


Participation Criteria
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Eligibility Criteria
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Key Inclusion Criteria: Has SARS-CoV-2-positive antigen or molecular diagnostic test (by validated SARS-CoV-2 antigen, RT-PCR, or other molecular diagnostic assay, using an appropriate sample such as NP, nasal, oropharyngeal [OP], or saliva) ≤72 hours prior to randomization and no alternative explanation for current clinical condition. A historical record of positive result from test conducted ≤72 hours prior to randomization is acceptable. Has symptoms consistent with COVID-19, as determined by investigator, with onset ≤10 days before randomization Hospitalized for ≤72 hours with at least 1 of the following at randomization; patients meeting more than one criterion will be categorized in the most severely affected category: Cohort 1A: With COVID-19 symptoms but not requiring supplemental oxygen Cohort 1: Maintains O2 saturation >93% on low-flow oxygen as defined in the protocol Cohort 2: High-intensity oxygen therapy without mechanical ventilation as defined in the protocol Cohort 3: On mechanical ventilation Key Exclusion Criteria: Phase 1 Only: Patients maintaining O2 saturation >94% on room air In the opinion of the investigator, unlikely to survive for >48 hours from screening Receiving extracorporeal membrane oxygenation (ECMO) Has new-onset stroke or seizure disorder during hospitalization Initiated on renal replacement therapy due to COVID-19 NOTE: Other protocol defined inclusion / exclusion criteria apply

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Phase 1/Phase 2/Phase 3
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: On Low-Flow Oxygen<br>Cohort 1 (C1): O2 saturation >93% on low-flow oxygen via nasal cannula, simple face mask, or other similar device | Drug: REGN10933+REGN10987 combination therapy<br>* Administered intravenously (IV) single dose<br>* Other names: imdevimab;Drug: Placebo<br>* Placebo IV Single Dose<br>|
| Experimental: With COVID-19 symptoms but not requiring supplemental O2<br>Cohort 1A (C1A): With COVID-19 symptoms but not requiring supplemental oxygen | Drug: REGN10933+REGN10987 combination therapy<br>* Administered intravenously (IV) single dose<br>* Other names: imdevimab;Drug: Placebo<br>* Placebo IV Single Dose<br>|
| Experimental: High O2 No Mechanical Ventilation<br>Cohort 2 (C2): On high-intensity oxygen (O2) therapy but not on mechanical ventilation | Drug: REGN10933+REGN10987 combination therapy<br>* Administered intravenously (IV) single dose<br>* Other names: imdevimab;Drug: Placebo<br>* Placebo IV Single Dose<br>|
| Experimental: On Mechanical Ventilation<br>Cohort 3 (C3): On mechanical ventilation | Drug: REGN10933+REGN10987 combination therapy<br>* Administered intravenously (IV) single dose<br>* Other names: imdevimab;Drug: Placebo<br>* Placebo IV Single Dose<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pooled Analysis (Phase 3 [Cohort 1] and Phase 2 [Cohort 1A]): Time-weighted Average (TWA) Change in Viral Load in Nasopharyngeal (NP) Samples Based on Seronegative mFAS | Time-weighted average daily change from Day 1 to Day 7 in viral load (log10 copies/mL), as measured by reverse transcription quantitative polymerase chain reaction (RT-qPCR) in nasopharyngeal (NP) swab samples. | Day 1 to Day 7 | 
| Pooled Analysis (Phase 3 [Cohort 1] and Phase 2 [Cohort 1A]): Percentage of Participants Who Died or Went on Mechanical Ventilation From Day 6 Through Day 29 Based on High Viral Load mFAS | Percentage of participants who died or went on mechanical ventilation from Day 6 through Day 29 based on high viral load mFAS were reported. | Day 6 to Day 29 | 
| Pooled Analysis (Phase 3 [Cohort 1] and Phase 2 [Cohort 1A]): Percentage of Participants Who Died or Went on Mechanical Ventilation From Day 6 Through Day 29 Based on Seronegative mFAS | Percentage of participants who died or went on mechanical ventilation from Day 6 through Day 29 based on seronegative mFAS were reported. | Day 6 to Day 29 | 
| Pooled Analysis (Phase 3 [Cohort 1] and Phase 2 [Cohort 1A]): Percentage of Participants Who Died or Went on Mechanical Ventilation From Day 6 Through Day 29 Based on Overall mFAS | Percentage of participants who died or went on mechanical ventilation from Day 6 through Day 29 based on overall FAS were reported. | Day 6 to Day 29 | 
| Pooled Analysis (Phase 3 [Cohort 1] and Phase 2 [Cohort 1A]): Percentage of Participants Who Died or Went on Mechanical Ventilation From Day 1 Through Day 29 Based on High Viral Load mFAS | Percentage of participants who died or went on mechanical ventilation from Day 1 through Day 29 based on high viral load mFAS were reported. | Day 1 to Day 29 | 
| Pooled Analysis (Phase 3 [Cohort 1] and Phase 2 [Cohort 1A]): Percentage of Participants Who Died or Went on Mechanical Ventilation From Day 1 Through Day 29 Based on Seronegative mFAS | Percentage of participants who died or went on mechanical ventilation from Day 1 through Day 29 based on seronegative mFAS were reported. | Day 1 to Day 29 | 
| Pooled Analysis (Phase 3 [Cohort 1] and Phase 2 [Cohort 1A]): Percentage of Participants Who Died or Went on Mechanical Ventilation From Day 1 Through Day 29 Based on Overall mFAS | Percentage of participants who died or went on mechanical ventilation from Day 1 through Day 29 based on overall mFAS were reported. | Day 1 to Day 29 | 
| Pooled Analysis (Phase 1 [Cohort 1] and Phase 2 [Cohort 1]): Number of Participants With Treatment-Emergent Serious Adverse Events | Treatment-emergent adverse events are defined as those that are not present at baseline or represent the exacerbation of a pre-existing condition during the observation period. | Up to Day 169 | 
| Pooled Analysis (Phase 1 [Cohort 1] and Phase 2 [Cohort 1]): Number of Participants With Grade >=2 Infusion Related Reactions up to Day 4 | Infusion-related reactions are defined as any relevant adverse event that occurs during the infusion or up to day 4. The severity of adverse events (including test findings classified as adverse events) were graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE). | Up to Day 4 | 
| Pooled Analysis (Phase 1 [Cohort 1] and Phase 2 [Cohort 1]): Number of Participants With Grade >=2 Hypersensitivity Reactions Up to Day 29 | Hypersensitivity reactions are defined as any relevant adverse event that occurs during the infusion or up to study day 29. The severity of adverse events (including test findings classified as adverse events) were graded according to NCI-CTCAE. | Up to Day 29 | 
| Pooled Analysis (Phase 1 [Cohort 1] and Phase 2 [Cohort 1]): Cumulative Incidence of Death or Mechanical Ventilation Based on Seronegative mFAS | Cumulative incidence percentage was estimated using Kaplan-Meier method. | Up to Day 29 | 
| Pooled Analysis (Phase 1 [Cohort 1] and Phase 2 [Cohort 1]): Cumulative Incidence of Death or Mechanical Ventilation Based on High Viral Load mFAS | Cumulative incidence percentage was estimated using Kaplan-Meier method. | Up to Day 29 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pooled Analysis Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Percentage of Participants Who Went on Mechanical Ventilation by Day 29 Based on High Viral Load mFAS | Percentage of participants who went on mechanical ventilation by Day 29 based on High Viral Load mFAS in pooled analysis phase 3 (Cohort 1) and phase 2 (Cohort 1A) was reported. | by Day 29 | 
| Pooled Analysis Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Percentage of Participants Who Went on Mechanical Ventilation by Day 29 Based on Seronegative mFAS | Percentage of participants who went on mechanical ventilation at Day 29 based on Seronegative mFAS in pooled analysis phase 3 (Cohort 1) and phase 2 (Cohort 1A) was reported. | by Day 29 | 
| Pooled Analysis Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Percentage of Participants Who Died From Day 6 Through Day 29 Based on High Viral Load mFAS | Percentage of participants who died from Day 6 through Day 29 based on high viral load mFAS were reported. | Day 6 to Day 29 | 
| Pooled Analysis Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Percentage of Participants Who Died From Day 6 Through Day 29 Based on Seronegative mFAS | Percentage of participants who died from Day 6 through Day 29 Based on seronegative mFAS in pooled analysis phase 3 (cohort 1) and phase 2 (cohort 1A) were reported. | Day 6 to Day 29 | 
| Pooled Analysis Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Percentage of Participants Who Died From Day 1 Through Day 29 Based on High Viral Load mFAS | Percentage of participants who died from Day 1 through Day 29 based on High Viral Load mFAS in pooled analysis phase 3 (Cohort 1) and phase 2 (Cohort 1A) were reported. | Day 1 to Day 29 | 
| Pooled Analysis Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Percentage of Participants Who Died From Day 1 Through Day 29 Based on Seronegative mFAS | Percentage of participants who died from Day 1 through Day 29 based on seronegative mFAS in pooled analysis phase 3 (Cohort 1) and phase 2 (Cohort 1A) were reported. | Day 1 to Day 29 | 
| Pooled Analysis Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Percentage of Participants Who Were Discharged by Day 29 Based on High Viral Load mFAS | Percentage of participants who were discharged by Day 29 based on High Viral Load mFAS in Phase 3 (Cohort 1) and Phase 2 (Cohort 1A) were reported. | by Day 29 | 
| Pooled Analysis Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Percentage of Participants Who Were Discharged by Day 29 Based on Seronegative mFAS | Percentage of participants who were discharged by Day 29 based on seronegative mFAS in Phase 3 (Cohort 1) and Phase 2 (Cohort 1A) were reported. | by Day 29 | 
| Pooled Analysis Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Percentage of Participants Who Died or Were Readmitted to Hospital Over Time Based on High Viral Load mFAS | Percentage of participants who died or were readmitted to hospital over time based on High Viral Load mFAS in Phase 3 (Cohort 1) and Phase 2 (Cohort 1A)were reported. Readmission to hospital was based on investigator report. | Up to Day 29 | 
| Pooled Analysis Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Percentage of Participants Who Died or Were Readmitted to Hospital by Day 29 Based on Seronegative mFAS | Percentage of participants who died or were readmitted to hospital at Day 29 based on seronegative mFAS in phase 3 (Cohort 1) and phase 2 (Cohort 1A) were reported. Readmission to hospital was based on investigator report. | by Day 29 | 
| Pooled Analysis Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Cumulative Incidence of Death (ie, Overall Survival) by Day 29 Based on High Viral Load mFAS | Overall Survival was defined as time interval from randomization to death. Percentage of participants with cumulative incidence of death (ie, overall survival) at Day 29 from randomization based on High Viral Load mFAS in Phase 3 (Cohort 1) and Phase 2 (Cohort 1A) were reported. Cumulative incidence percentage was estimated using Kaplan-Meier method. | by Day 29 | 
| Pooled Analysis Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Cumulative Incidence of Death (ie, Overall Survival) by Day 29 Based on Seronegative mFAS | Overall Survival was defined as time interval from randomization to death. Percentage of participants with cumulative incidence of death (ie, overall survival) at Day 29 from randomization based on seronegative mFAS in phase 3 (Cohort 1) and phase 2 (Cohort 1A)were reported. Cumulative incidence percentage was estimated using Kaplan-Meier method. | by Day 29 | 
| Pooled Analysis Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Cumulative Incidence of Mechanical Ventilation by Day 29 Based on High Viral Load mFAS | Number of participants with cumulative incidence of mechanical ventilation by Day 29 based on High Viral Load mFAS in Phase 3 (Cohort 1) and Phase 2 (Cohort 1A) were reported. Cumulative incidence percentage was estimated using Kaplan-Meier method. | by Day 29 | 
| Pooled Analysis Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Cumulative Incidence of Mechanical Ventilation by Day 29 Based on Seronegative mFAS | Percentage of participants with cumulative incidence of mechanical ventilation by Day 29 based on seronegative mFAS in phase 3 (Cohort 1) and phase 2 (Cohort 1A) were reported. Cumulative incidence percentage was estimated using Kaplan-Meier method. | by Day 29 | 
| Pooled Analysis Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Cumulative Incidence of Death or Mechanical Ventilation by Day 29 Based on High Viral Load mFAS | Percentage of participants with cumulative incidence of death or mechanical ventilation by Day 29 based on High Viral Load mFAS in Phase 3 (Cohort 1) and Phase 2 (Cohort 1A) were reported. Cumulative incidence percentage was estimated using Kaplan-Meier method. | by Day 29 | 
| Pooled Analysis Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Cumulative Incidence of Death or Mechanical Ventilation by Day 29 Based on Seronegative mFAS | Percentage of participants with cumulative incidence of death or mechanical ventilation by Day 29 based on seronegative mFAS in phase 3 (Cohort 1) and phase 2 (Cohort 1A) were reported. Cumulative incidence percentage was estimated using Kaplan-Meier method. | by Day 29 | 
| Pooled Analysis Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Time to Discharge From Hospital Based on High Viral Load mFAS | Time to discharge from hospital based on High Viral Load mFAS in Phase 3 (Cohort 1) and Phase 2 (Cohort 1A) was reported. | Up to Day 56 | 
| Pooled Analysis Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Time to Discharge From Hospital Based on Seronegative mFAS | Time to discharge from hospital based on Seronegative mFAS in Phase 3 (Cohort 1) and Phase 2 (Cohort 1A) was reported. | Up to Day 56 | 
| Pooled Analysis (Phases 1/2/3 [Cohort 1] and Phase 2 [Cohorts 1A/2/3]): Number of Participants With Treatment-Emergent Serious Adverse Events |  | Up to Day 169 | 
| Pooled Analysis (Phases 1/2/3 [Cohort 1] and Phase 2 [Cohorts 1A/2/3]): Number of Participants With Grade >=2 Infusion Related Reactions up to Day 4 |  | Up to Day 4 | 
| Pooled Analysis (Phases 1/2/3 [Cohort 1] and Phase 2 [Cohorts 1A/2/3]): Number of Participants With Grade >=2 Hypersensitivity Reactions Up to Day 29 |  | Up to Day 29 | 
| Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Percentage of Participants Who Went on Mechanical Ventilation by Day 29 Based on Seronegative mFAS | Percentage of participants who went on mechanical ventilation in phase 3 (Cohort 1) and phase 2 (Cohort 1A) was reported. | by Day 29 | 
| Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Percentage of Participants Who Died From Day 6 Through Day 29 Based on Seronegative mFAS | Percentage of participants who died from Day 6 through Day 29 in phase 3 (cohort 1) and phase 2 (cohort 1A) were reported. | Day 6 to Day 29 | 
| Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Percentage of Participants Who Died From Day 1 Through Day 29 Based on Seronegative mFAS | Percentage of participants who died from Day 1 through Day 29 in phase 3 (Cohort 1) and phase 2 (Cohort 1A) were reported. | Day 1 to Day 29 | 
| Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Percentage of Participants Who Were Discharged by Day 29 Based on Seronegative mFAS | Percentage of participants who were discharged in Phase 3 (Cohort 1) and Phase 2 (Cohort 1A) by Day 29 were reported. | by Day 29 | 
| Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Percentage of Participants Who Died or Were Readmitted to Hospital by Day 29 Based on Seronegative mFAS | Percentage of participants who died or were readmitted to hospital in phase 3 (Cohort 1) and phase 2 (Cohort 1A) by Day 29 were reported. Readmission to hospital was based on investigator report. | Up to Day 29 | 
| Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Cumulative Incidence of Death up to Day 29 Based on Seronegative mFAS | Percentage of participants with cumulative incidence of death in Phase 3 (Cohort 1) and Phase 2 (Cohort 1A) up to Day 29 from randomization were reported. Cumulative incidence percentage was estimated using Kaplan-Meier method. | Up to Day 29 | 
| Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Cumulative Incidence of Mechanical Ventilation by Day 29 Based on Seronegative mFAS | Percentage of participants with cumulative incidence of mechanical ventilation in Phase 3 (Cohort 1) and Phase 2 (Cohort 1A) by Day 29 were reported. Cumulative incidence percentage was estimated using Kaplan-Meier method. | by Day 29 | 
| Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Cumulative Incidence of Death or Mechanical Ventilation by Day 29 Based on Seronegative mFAS | Percentage of participants with cumulative incidence of death or mechanical ventilation in Phase 3 (Cohort 1) and Phase 2 (Cohort 1A) by Day 29 were reported. Cumulative incidence percentage was estimated using Kaplan-Meier method. | by Day 29 | 
| Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Time to Discharge From Hospital Based on Seronegative mFAS | Time to discharge from hospital up to Day 56 was reported. | Up to Day 56 | 
| Phase 3 [Cohort 1] and Phase 2 [Cohort 1A]: TWA Change From Baseline Viral Load (Seronegative mFAS) in NP Samples up to Day 11 Based on Seronegative mFAS | TWA change from baseline in viral load up to Day 11 was calculated for each participant using the trapezoidal rule as the area under the curve for change from baseline at each time point divided by the time interval for the observation period. TWA change from baseline viral load in NP samples through Day 11, was measured by RT-qPCR in NP swab samples was reported. Baseline was defined as the last non-missing value measured prior to dosing. Negative changes indicate improvement in viral load. | Day 1 to Day 11 | 
| Phase 3 [Cohort 1] and Phase 2 [Cohort 1A]: TWA Change From Baseline Viral Load (Seronegative mFAS) in NP Samples up to Day 29 | TWA change from baseline in viral load up to Day 29 was calculated for each participant using the trapezoidal rule as the area under the curve for change from baseline at each time point divided by the time interval for the observation period. TWA change from baseline viral load in NP samples through Day 29, was measured by quantitative RT-qPCR in NP swab samples was reported. Baseline was defined as the last non-missing value measured prior to dosing. Negative changes indicate improvement in viral load. | Day 1 to Day 29 | 
| Phase 3 [Cohort 1] and Phase 2 [Cohort 1A]: Change From Baseline in Viral Load (Seronegative mFAS) as Measured by RT-qPCR in NP Swabs Over Time | Change from baseline in viral load as measured by RT-qPCR in NP swabs over time was reported. Baseline was defined as the last non-missing value measured prior to dosing. Negative changes indicates improvement in viral load. | Days 3, 5, 7, 9, 11, 13, 15, 22 and 29 | 
| Phase 3 [Cohort 1] and Phase 2 [Cohort 1A]: Percent Change From Baseline in Viral Load (Seronegative mFAS) as Measured by RT-qPCR in NP Swabs Over Time | Percent change from baseline in viral load as measured by RT-qPCR in NP swabs over time was reported. Baseline was defined as the last non-missing value measured prior to dosing. Negative changes indicates improvement in viral load. | Days 3, 5, 7, 9, 11, 13, 15, 22 and 29 | 
| Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Percentage of Participants Who Went on Mechanical Ventilation by Day 29 Based on High Viral Load mFAS | Percentage of participants who went on mechanical ventilation in phase 3 (Cohort 1) and phase 2 (Cohort 1A) was reported. | by Day 29 | 
| Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Percentage of Participants Who Died From Day 6 to Day 29 Based on High Viral Load mFAS | Percentage of participants who died in phase 3 (Cohort 1) and phase 2 (Cohort 1A) was reported. | Day 6 to Day 29 | 
| Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Percentage of Participants Who Died From Day 1 to Day 29 Based on High Viral Load mFAS | Percentage of participants who died in phase 3 (Cohort 1) and phase 2 (Cohort 1A) was reported. | Day 1 to Day 29 | 
| Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Percentage of Participants Who Were Discharged by Day 29 Based on High Viral Load mFAS | Percentage of participants who were discharged in phase 3 (Cohort 1) and phase 2 (Cohort 1A) was reported. | by Day 29 | 
| Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Percentage of Participants Who Died or Were Readmitted to Hospital Over Time Based on High Viral Load mFAS | Percentage of participants who died or were readmitted to hospital in phase 3 (Cohort 1) and phase 2 (Cohort 1A) over time were reported. Readmission to hospital was based on investigator report. | Up to Day 29 | 
| Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Cumulative Incidence of Death Over Time Based on High Viral Load mFAS | Cumulative Incidence of Death Over Time in phase 3 (Cohort 1) and phase 2 (Cohort 1A) were reported. Cumulative incidence percentage was estimated using Kaplan-Meier method. | Up to Day 29 | 
| Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Cumulative Incidence of Mechanical Ventilation Over Time Based on High Viral Load mFAS | Cumulative Incidence of Mechanical Ventilation Over Time in phase 3 (Cohort 1) and phase 2 (Cohort 1A) were reported. Cumulative incidence percentage was estimated using Kaplan-Meier method. | Up to Day 29 | 
| Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Cumulative Incidence of Death or Mechanical Ventilation Over Time Based on High Viral Load mFAS | Cumulative Incidence of Death or Mechanical Ventilation Over Time in phase 3 (Cohort 1) and phase 2 (Cohort 1A) were reported. Cumulative incidence percentage was estimated using Kaplan-Meier method. | Up to Day 29 | 
| Phase 3 (Cohort 1) and Phase 2 (Cohort 1A): Time to Discharge Based on High Viral Load mFAS | Time to Discharge in phase 3 (Cohort 1) and phase 2 (Cohort 1A) were reported. | Up to Day 56 | 
| Phase 1 [Cohort 1] and Phase 2 [Cohort 1]): Time-weighted Average (TWA) Change in Viral Load in Nasopharyngeal (NP) Samples Over Time Based on Seronegative mFAS | Time-weighted average daily change over time up to Day 29 in viral load (log10 copies/mL), as measured by reverse transcription quantitative polymerase chain reaction (RT-qPCR) in nasopharyngeal (NP) swab samples. | Up to Day 29 | 
| Phase 1 [Cohort 1] and Phase 2 [Cohort 1]): Change From Baseline as Measured by RT-qPCR in NP Swabs Over Time Based on Seronegative mFAS | Change from baseline in viral load as measured by RT-qPCR in NP swabs over time was reported. Baseline was defined as the last non-missing value measured prior to dosing. Negative changes indicates improvement in viral load. | Days 3, 5, 7, 9, 11, 13, 15, 22 and 29 | 
| Phase 1 [Cohort 1] and Phase 2 [Cohort 1]: Percentage of Participants Who Died or Went On Mechanical Ventilation by Day 29 Based on Seronegative mFAS |  | Through Day 29 | 
| Phase 1 [Cohort 1] and Phase 2 [Cohort 1]: Percentage of Participants Who Died or Went On Mechanical Ventilation by Day 29 Based on High Viral Load mFAS |  | Through Day 29 | 
| Phase 1 [Cohort 1]: Area Under the Concentration-Time Curve From Time 0 to 28 Days Post-dose (AUC0-28) |  | Up to Day 28 | 
| Concentration at the End of Infusion (Ceoi) |  | Day 1 | 
| Concentration at Day 28 (C28) |  | Day 28 | 
| Immunogenicity as Measured by Anti-drug Antibodies (ADAs) to REGN10933 |  | Through Day 169 | 
| Immunogenicity as Measured by Anti-drug Antibodies (ADAs) to REGN10987 |  | Through Day 169 | 
| Immunogenicity as Measured by Neutralizing Antibody Status (NAb) to REGN10933 |  | Through Day 57 | 
| Immunogenicity as Measured by Neutralizing Antibody Status (NAb) to REGN10987 |  | Through Day 57 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Coronavirus disease 2019 (COVID-19), Severe acute respiratory syndrome coronavirus 2 (SARS-COV-2), coronavirus, acute respiratory distress syndrome