inclusion criteria: stage i: * body mass index (bmi) less than or equal to (\<=) 35 kilogram per meter square (kg/m\^2) * positive laboratory test for severe acute respiratory syndrome coronavirus 2 (sars-cov-2) or respiratory infection with recent exposure to a person with laboratory-proven sars-cov-2 * patient has an ordinal scale score between 5 and 7, inclusive, using the who 7os * hypoxemia defined by saturation of peripheral oxygen (spo2) of less than (\<) 95 percent (%) on room air or acute respiratory distress syndrome (ards) * occurrence of at least two of the following criteria: fever greater than (\>) 38.0 degree celsius, tachycardia \>90 beats/minute, tachypnea \>20 breaths/minute, leucocytosis \>12\*109 per liter (/l) or leucopoenia \<4 \*10\^9/l * enrollment must occur within 72 hours from the initiation of mechanical ventilation or high-flow oxygen * a signed informed consent form (icf) from the patient or the patient's legally authorized representative must be available (telephone consent is acceptable) * female patients may not be pregnant, lactating, or breastfeeding * female patients of childbearing potential must have negative result for pregnancy test at screening * male patients must agree to use a barrier method of contraception during the study and for 90 days after the last dose * participants must have an estimated glomerular filtration rate of greater than or equal to (\>=) 45 milliliter per minute per 1.73 meter square (ml/min/1.73 m\^2) at screening * must agree not to enroll in another study of an investigational agent prior to completion of this study. stage ii: * positive laboratory test for sars-cov-2 or respiratory infection with recent exposure to a person with laboratory-proven sars-cov-2 * patient has an ordinal scale score between 5 and 8, inclusive, using the who 10os. * patients with an ordinal score of 5 must be receiving oxygen by mask at a rate of 10 l or greater * hypoxemia defined by spo2 of \<95% on room air or diagnosed with ards * hyperinflammation (elevated crp \> upper limit of local normal for laboratory range) at screening * a signed icf from the patient or the patient's legally authorized representative must be available (telephone consent is acceptable) * female patients may not be pregnant, lactating, or breastfeeding * female patients of childbearing potential must have negative result for pregnancy test at screening * patients must have an estimated glomerular filtration rate of \>= 30 ml/min/1.73 m\^2 at screening * male patients must agree to use a barrier method of contraception during the study and for 90 days after the last dose * must agree not to enroll in another study of an investigational agent prior to completion of this study.

inclusion criteria: stage i: * body mass index (bmi) less than or equal to (\<=) 35 kilogram per meter square (kg/m\^2) * positive laboratory test for severe acute respiratory syndrome coronavirus 2 (sars-cov-2) or respiratory infection with recent exposure to a person with laboratory-proven sars-cov-2 * patient has an ordinal scale score between 5 and 7, inclusive, using the who 7os * hypoxemia defined by saturation of peripheral oxygen (spo2) of less than (\<) 95 percent (%) on room air or acute respiratory distress syndrome (ards) * occurrence of at least two of the following criteria: fever greater than (\>) 38.0 degree celsius, tachycardia \>90 beats/minute, tachypnea \>20 breaths/minute, leucocytosis \>12\*109 per liter (/l) or leucopoenia \<4 \*10\^9/l * enrollment must occur within 72 hours from the initiation of mechanical ventilation or high-flow oxygen * a signed informed consent form (icf) from the patient or the patient's legally authorized representative must be available (telephone consent is acceptable) * female patients may not be pregnant, lactating, or breastfeeding * female patients of childbearing potential must have negative result for pregnancy test at screening * male patients must agree to use a barrier method of contraception during the study and for 90 days after the last dose * participants must have an estimated glomerular filtration rate of greater than or equal to (\>=) 45 milliliter per minute per 1.73 meter square (ml/min/1.73 m\^2) at screening * must agree not to enroll in another study of an investigational agent prior to completion of this study. stage ii: * positive laboratory test for sars-cov-2 or respiratory infection with recent exposure to a person with laboratory-proven sars-cov-2 * patient has an ordinal scale score between 5 and 8, inclusive, using the who 10os. * patients with an ordinal score of 5 must be receiving oxygen by mask at a rate of 10 l or greater * hypoxemia defined by spo2 of \<95% on room air or diagnosed with ards * hyperinflammation (elevated crp \> upper limit of local normal for laboratory range) at screening * a signed icf from the patient or the patient's legally authorized representative must be available (telephone consent is acceptable) * female patients may not be pregnant, lactating, or breastfeeding * female patients of childbearing potential must have negative result for pregnancy test at screening * patients must have an estimated glomerular filtration rate of \>= 30 ml/min/1.73 m\^2 at screening * male patients must agree to use a barrier method of contraception during the study and for 90 days after the last dose * must agree not to enroll in another study of an investigational agent prior to completion of this study.

inclusion criteria: stage i: body mass index (bmi) less than or equal to (<=) 35 kilogram per meter square (kg/m^2) positive laboratory test for severe acute respiratory syndrome coronavirus 2 (sars-cov-2) or respiratory infection with recent exposure to a person with laboratory-proven sars-cov-2 patient has an ordinal scale score between 5 and 7, inclusive, using the who 7os hypoxemia defined by saturation of peripheral oxygen (spo2) of less than (<) 95 percent (%) on room air or acute respiratory distress syndrome (ards) occurrence of at least two of the following criteria: fever greater than (>) 38.0 degree celsius, tachycardia >90 beats/minute, tachypnea >20 breaths/minute, leucocytosis >12*109 per liter (/l) or leucopoenia <4 *10^9/l enrollment must occur within 72 hours from the initiation of mechanical ventilation or high-flow oxygen a signed informed consent form (icf) from the patient or the patient's legally authorized representative must be available (telephone consent is acceptable) female patients may not be pregnant, lactating, or breastfeeding female patients of childbearing potential must have negative result for pregnancy test at screening male patients must agree to use a barrier method of contraception during the study and for 90 days after the last dose participants must have an estimated glomerular filtration rate of greater than or equal to (>=) 45 milliliter per minute per 1.73 meter square (ml/min/1.73 m^2) at screening must agree not to enroll in another study of an investigational agent prior to completion of this study. stage ii: positive laboratory test for sars-cov-2 or respiratory infection with recent exposure to a person with laboratory-proven sars-cov-2 patient has an ordinal scale score between 5 and 8, inclusive, using the who 10os. patients with an ordinal score of 5 must be receiving oxygen by mask at a rate of 10 l or greater hypoxemia defined by spo2 of <95% on room air or diagnosed with ards hyperinflammation (elevated crp > upper limit of local normal for laboratory range) at screening a signed icf from the patient or the patient's legally authorized representative must be available (telephone consent is acceptable) female patients may not be pregnant, lactating, or breastfeeding female patients of childbearing potential must have negative result for pregnancy test at screening patients must have an estimated glomerular filtration rate of >= 30 ml/min/1.73 m^2 at screening male patients must agree to use a barrier method of contraception during the study and for 90 days after the last dose must agree not to enroll in another study of an investigational agent prior to completion of this study.

inclusion criteria: stage i: body mass index (bmi) less than or equal to (<=) 35 kilogram per meter square (kg/m^2) positive laboratory test for severe acute respiratory syndrome coronavirus 2 (sars-cov-2) or respiratory infection with recent exposure to a person with laboratory-proven sars-cov-2 patient has an ordinal scale score between 5 and 7, inclusive, using the who 7os hypoxemia defined by saturation of peripheral oxygen (spo2) of less than (<) 95 percent (%) on room air or acute respiratory distress syndrome (ards) occurrence of at least two of the following criteria: fever greater than (>) 38.0 degree celsius, tachycardia >90 beats/minute, tachypnea >20 breaths/minute, leucocytosis >12*109 per liter (/l) or leucopoenia <4 *10^9/l enrollment must occur within 72 hours from the initiation of mechanical ventilation or high-flow oxygen a signed informed consent form (icf) from the patient or the patient's legally authorized representative must be available (telephone consent is acceptable) female patients may not be pregnant, lactating, or breastfeeding female patients of childbearing potential must have negative result for pregnancy test at screening male patients must agree to use a barrier method of contraception during the study and for 90 days after the last dose participants must have an estimated glomerular filtration rate of greater than or equal to (>=) 45 milliliter per minute per 1.73 meter square (ml/min/1.73 m^2) at screening must agree not to enroll in another study of an investigational agent prior to completion of this study. stage ii: positive laboratory test for sars-cov-2 or respiratory infection with recent exposure to a person with laboratory-proven sars-cov-2 patient has an ordinal scale score between 5 and 8, inclusive, using the who 10os. patients with an ordinal score of 5 must be receiving oxygen by mask at a rate of 10 l or greater hypoxemia defined by spo2 of <95% on room air or diagnosed with ards hyperinflammation (elevated crp > upper limit of local normal for laboratory range) at screening a signed icf from the patient or the patient's legally authorized representative must be available (telephone consent is acceptable) female patients may not be pregnant, lactating, or breastfeeding female patients of childbearing potential must have negative result for pregnancy test at screening patients must have an estimated glomerular filtration rate of >= 30 ml/min/1.73 m^2 at screening male patients must agree to use a barrier method of contraception during the study and for 90 days after the last dose must agree not to enroll in another study of an investigational agent prior to completion of this study.

key inclusion criteria: - body mass index (bmi) less than or equal to (<=) 35 kilogram per meter square (kg/m^2) - positive laboratory test for severe acute respiratory syndrome coronavirus 2 (sars-cov-2) or respiratory infection with recent exposure to a person with laboratory-proven sars-cov-2 - hypoxemia defined by saturation of peripheral oxygen (spo2) of less than (<) 95 percent (%) on room air or acute respiratory distress syndrome (ards) - occurrence of at least two of the following criteria: fever greater than (>) 38.0 degree celsius, tachycardia >90 beats/minute, tachypnea >20 breaths/minute, leucocytosis >12*109 per liter (/l) or leucopoenia <4 *109/l - participants must have an estimated glomerular filtration rate of greater than or equal to (>=) 45 milliliter per minute per 1.73 meter square (ml/min/1.73 m^2) at screening key

key inclusion criteria: - body mass index (bmi) less than or equal to (<=) 35 kilogram per meter square (kg/m^2) - positive laboratory test for severe acute respiratory syndrome coronavirus 2 (sars-cov-2) or respiratory infection with recent exposure to a person with laboratory-proven sars-cov-2 - hypoxemia defined by saturation of peripheral oxygen (spo2) of less than (<) 95 percent (%) on room air or acute respiratory distress syndrome (ards) - occurrence of at least two of the following criteria: fever greater than (>) 38.0 degree celsius, tachycardia >90 beats/minute, tachypnea >20 breaths/minute, leucocytosis >12*109 per liter (/l) or leucopoenia <4 *109/l - participants must have an estimated glomerular filtration rate of greater than or equal to (>=) 45 milliliter per minute per 1.73 meter square (ml/min/1.73 m^2) at screening key