1. Requiring either invasive or non-invasive ventilation including continuous positive airway pressure (CPAP) or high flow nasal oxygen at any point before baseline 2. Grade ≥5 severity on the WHO COVID-19 Ordinal Scale 3. O2 saturation < 90% on ≥60% inspired oxygen at baseline 4. In the opinion of the investigator, progression to death is inevitable within the next 24 hours, irrespective of the provision of therapy 5. Known severe allergic reactions to the investigational agents 6. Use of drugs within the preceding 14 days that are known to interact with any study treatment 7. Child Pugh B or C grade hepatic dysfunction 8. End stage renal failure (ESRF) 9. Pregnant or breast feeding 10. Participation in other clinical trials

1. Requiring either invasive or non-invasive ventilation including continuous positive airway pressure (CPAP) or high flow nasal oxygen at any point before baseline 2. Grade ≥5 severity on the WHO COVID-19 Ordinal Scale 3. O2 saturation < 90% on ≥60% inspired oxygen at baseline 4. In the opinion of the investigator, progression to death is inevitable within the next 24 hours, irrespective of the provision of therapy 5. Known severe allergic reactions to the investigational agents 6. Use of drugs within the preceding 14 days that are known to interact with any study treatment 7. Child Pugh B or C grade hepatic dysfunction 8. End stage renal failure (ESRF) 9. Pregnant or breast feeding 10. Participation in other clinical trials