key inclusion criteria: * adults ≥ 18 years old (for us only: patients ≥ 12 years old, although no children ever enrolled. this was an adult trial.) * body weight ≥40 kg * informed consent must be obtained prior to participation in this study. for us patients 12 - \< 18 years old; parent/guardian consent must be obtained and assent if applicable. * clinically diagnosed with sars-cov-2 virus by pcr or by other approved diagnostic methodology * hospitalized with covid-19-induced pneumonia evidenced by chest x-ray or ct scan with pulmonary infiltrates * spo2 ≤ 93% on room air or arterial oxygen partial pressure (pao2)/ fraction of inspired oxygen (fio2) \< 300mmhg * c-reactive protein ≥20 mg/l or ferritin level ≥600 µg/l key

key inclusion criteria: * adults ≥ 18 years old (for us only: patients ≥ 12 years old, although no children ever enrolled. this was an adult trial.) * body weight ≥40 kg * informed consent must be obtained prior to participation in this study. for us patients 12 - \< 18 years old; parent/guardian consent must be obtained and assent if applicable. * clinically diagnosed with sars-cov-2 virus by pcr or by other approved diagnostic methodology * hospitalized with covid-19-induced pneumonia evidenced by chest x-ray or ct scan with pulmonary infiltrates * spo2 ≤ 93% on room air or arterial oxygen partial pressure (pao2)/ fraction of inspired oxygen (fio2) \< 300mmhg * c-reactive protein ≥20 mg/l or ferritin level ≥600 µg/l key

key inclusion criteria: - adults ≥ 18 years old (for us only: patients ≥ 12 years old, although no children ever enrolled. this was an adult trial.) - body weight ≥40 kg - informed consent must be obtained prior to participation in this study. for us patients 12 - < 18 years old; parent/guardian consent must be obtained and assent if applicable. - clinically diagnosed with sars-cov-2 virus by pcr or by other approved diagnostic methodology - hospitalized with covid-19-induced pneumonia evidenced by chest x-ray or ct scan with pulmonary infiltrates - spo2 ≤ 93% on room air or arterial oxygen partial pressure (pao2)/ fraction of inspired oxygen (fio2) < 300mmhg - c-reactive protein ≥20 mg/l or ferritin level ≥600 µg/l key

key inclusion criteria: - adults ≥ 18 years old (for us only: patients ≥ 12 years old, although no children ever enrolled. this was an adult trial.) - body weight ≥40 kg - informed consent must be obtained prior to participation in this study. for us patients 12 - < 18 years old; parent/guardian consent must be obtained and assent if applicable. - clinically diagnosed with sars-cov-2 virus by pcr or by other approved diagnostic methodology - hospitalized with covid-19-induced pneumonia evidenced by chest x-ray or ct scan with pulmonary infiltrates - spo2 ≤ 93% on room air or arterial oxygen partial pressure (pao2)/ fraction of inspired oxygen (fio2) < 300mmhg - c-reactive protein ≥20 mg/l or ferritin level ≥600 µg/l key

key inclusion criteria: - adults ≥ 18 years old (for us only: patients ≥ 12 years old, but no paediatric patients were enrolled in this study. this was an adult study) - body weight ≥40 kg - informed consent must be obtained prior to participation in this study. for us patients 12 - < 18 years old; parent/guardian consent must be obtained and assent if applicable. - clinically diagnosed with sars-cov-2 virus by pcr or by other approved diagnostic methodology - hospitalized with covid-19-induced pneumonia evidenced by chest x-ray or ct scan with pulmonary infiltrates - spo2 ≤ 93% on room air or arterial oxygen partial pressure (pao2)/ fraction of inspired oxygen (fio2) < 300mmhg - c-reactive protein ≥20 mg/l or ferritin level ≥600 µg/l key

key inclusion criteria: - adults ≥ 18 years old (for us only: patients ≥ 12 years old, but no paediatric patients were enrolled in this study. this was an adult study) - body weight ≥40 kg - informed consent must be obtained prior to participation in this study. for us patients 12 - < 18 years old; parent/guardian consent must be obtained and assent if applicable. - clinically diagnosed with sars-cov-2 virus by pcr or by other approved diagnostic methodology - hospitalized with covid-19-induced pneumonia evidenced by chest x-ray or ct scan with pulmonary infiltrates - spo2 ≤ 93% on room air or arterial oxygen partial pressure (pao2)/ fraction of inspired oxygen (fio2) < 300mmhg - c-reactive protein ≥20 mg/l or ferritin level ≥600 µg/l key

key inclusion criteria: - adults ≥ 18 years old (for us only: patients ≥ 12 years old, but no paediatric patients were enrolled in this study. this is was an adult study) - body weight ≥40 kg - informed consent must be obtained prior to participation in this study. for us patients 12 - < 18 years old; parent/guardian consent must be obtained and assent if applicable. - clinically diagnosed with sars-cov-2 virus by pcr or by other approved diagnostic methodology - hospitalized with covid-19-induced pneumonia evidenced by chest x-ray or ct scan with pulmonary infiltrates - spo2 ≤ 93% on room air or arterial oxygen partial pressure (pao2)/ fraction of inspired oxygen (fio2) < 300mmhg - c-reactive protein ≥20 mg/l or ferritin level ≥600 µg/l key

key inclusion criteria: - adults ≥ 18 years old (for us only: patients ≥ 12 years old, but no paediatric patients were enrolled in this study. this is was an adult study) - body weight ≥40 kg - informed consent must be obtained prior to participation in this study. for us patients 12 - < 18 years old; parent/guardian consent must be obtained and assent if applicable. - clinically diagnosed with sars-cov-2 virus by pcr or by other approved diagnostic methodology - hospitalized with covid-19-induced pneumonia evidenced by chest x-ray or ct scan with pulmonary infiltrates - spo2 ≤ 93% on room air or arterial oxygen partial pressure (pao2)/ fraction of inspired oxygen (fio2) < 300mmhg - c-reactive protein ≥20 mg/l or ferritin level ≥600 µg/l key

key inclusion criteria: - adults ≥ 18 years old (for us only: patients ≥ 12 years old) - body weight ≥40 kg - informed consent must be obtained prior to participation in this study. for us patients 12 - < 18 years old; parent/guardian consent must be obtained and assent if applicable. - clinically diagnosed with sars-cov-2 virus by pcr or by other approved diagnostic methodology - hospitalized with covid-19-induced pneumonia evidenced by chest x-ray or ct scan with pulmonary infiltrates - spo2 ≤ 93% on room air or arterial oxygen partial pressure (pao2)/ fraction of inspired oxygen (fio2) < 300mmhg - c-reactive protein ≥20 mg/l or ferritin level ≥600 µg/l key

key inclusion criteria: - adults ≥ 18 years old (for us only: patients ≥ 12 years old) - body weight ≥40 kg - informed consent must be obtained prior to participation in this study. for us patients 12 - < 18 years old; parent/guardian consent must be obtained and assent if applicable. - clinically diagnosed with sars-cov-2 virus by pcr or by other approved diagnostic methodology - hospitalized with covid-19-induced pneumonia evidenced by chest x-ray or ct scan with pulmonary infiltrates - spo2 ≤ 93% on room air or arterial oxygen partial pressure (pao2)/ fraction of inspired oxygen (fio2) < 300mmhg - c-reactive protein ≥20 mg/l or ferritin level ≥600 µg/l key