Trial of Tocilizumab for Treatment of Severe COVID-19: ARCHITECTS

Inclusion Criteria: * ii. Hospitalized with COVID-19 pneumonia, based on chest X-ray or CT scan AND iii. Evidence of hyperinflammation: IL-6\>40pg/mL (if available) OR CRP \>2 mg/dL OR ferritin \>2000 ng/mL AND iv. One or more of the following: impending need for requiring invasive or non-invasive mechanical ventilation OR shock requiring vasopressor (without evidence of bacterial / fungal infection) OR need for extracorporeal membrane oxygenation (ECMO) OR severe, refractor ARDS (PaO2/FiO2\<200 mmHg) Exclusion Criteria: Known severe allergic reactions to tocilizumab or other monoclonal antibodies * Active tuberculosis infection based on history * Suspected active bacterial, fungal, viral, or other infection (besides COVID-19) * In the opinion of the investigator, progression to death is imminent and inevitable within the next 24 hours, irrespective of the provision of treatments * Have received oral anti-rejection or immunomodulatory drugs (including tocilizumab) with the past 6 months * Participating in other drug clinical trials (participation in COVID-19 trials allowed) * Self-reported pregnant or breastfeeding * Any serious medical condition or abnormality of clinical laboratory tests that, in the investigator's judgment, precludes the patient's safe participation in and completion of the study * Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) \> 10 x upper limit of normal (ULN) detected within 24 hours at baseline * Absolute neutrophil count (ANC) \< 1000/mL at baseline * Platelet count \< 50,000/mL at baseline