Primary Outcomes
Measure: Concentration of C-Reactive Protein (CRP) Time: Day 7
Secondary Outcomes
Measure: Serum Concentration of Interleukin-6 (IL-6) Time: Days 1, 3, 7, 14, and 28
Measure: Serum Concentration of Soluble Interleukin Receptor (sIL-6R) Time: Days 1, 3, 7, 14, and 28
Measure: Serum Concentration of Ferritin Time: Days 1, 3, 7, 14, and 28
Measure: Serum Concentration of TCZ Following Administration of 8 mg/kg IV TCZ Time: At pre-defined intervals from first TCZ administration to Day 28
Measure: Serum Concentration of TCZ Following Administration of 4 mg/kg IV TCZ Time: At pre-defined intervals from first TCZ administration to Day 28
Measure: Clinical Status, as Assessed Using a 7-Category Ordinal Scale Time: Days 14 and 28
Measure: Time to Clinical Improvement, Defined as a National Early Warning Score 2 (NEWS2) of =2 Maintained for 24 Hours Time: Up to Day 28
Measure: Time to Improvement in at Least Two Categories Relative to Baseline on a 7-Category Ordinal Scale of Clinical Status Time: Up to Day 28
Measure: Duration of Supplemental Oxygen Use Time: Up to Day 28
Measure: Incidence of Intensive Care Unit (ICU) Stays Time: Up to Day 28
Measure: Incidence of Mechanical Ventilation Time: Up to Day 28
Measure: Duration of ICU Stay Time: Up to Day 28
Measure: Time to Clinical Failure, Defined as the Time to Death, Mechanical Ventilation, ICU Admission, or Withdrawal (whichever occurs first) Time: Up to Day 28
Measure: Mortality Rate Time: Days 7, 14, 21, 28, and 60
Measure: Time to Hospital Discharge or "Ready for Discharge" Time: Up to Day 28
Measure: Frequency of Addition of a Second Dose of TCZ Time: Up to Day 28
Measure: Pecentage of Participants with Adverse Events Time: Up to Day 28
Measure: SARS-CoV-2 (COVID-19) Viral Load Over Time Time: Up to Day 28
Measure: Time to Real-Time Polymerase Chain Reaction (PCR) Virus Negativity Time: Up to Day 28
Measure: Proportion of Participants with any Post-Treatment Infection Time: Up to Day 28