Outcome name: Proportion of subjects developing clinical failure by Day 29 with ruxolitinib + SoC versus placebo + SoC therapy.The odds of clinical failure will be analyzed by a logistic regression model with treatment group; region; baseline clinical status based on the 9-point ordinal scale; age; and gender as covariates. Measure:Clinical failure; defined as the occurrence of death; respiratory failure (require mechanical ventilation); or ICU care by Day 29Timepoints:Day 29

Outcome name: Proportion of subjects developing clinical failure by Day 29 with ruxolitinib + SoC versus placebo + SoC therapy.The odds of clinical failure will be analyzed by a logistic regression model with treatment group; region; baseline clinical status based on the 9-point ordinal scale; age; and gender as covariates. Measure:Clinical failure; defined as the occurrence of death; respiratory failure (require mechanical ventilation); or ICU care by Day 29Timepoints:Day 29