inclusion criteria: 1. male or non-pregnant female adult ≥ 18 years of age 2. diagnosed/confirmed with covid-19 by standard rt-pcr assay or equivalent testing within 7 days prior to randomization (day1). 3. hospitalized patient with severe illness caused by sars-cov-2 (note: prior or current use of remdesivir or dexamethasone (soc) are allowed under the investigator's discretion. concomitant treatment with other investigational antiviral drugs or immunomodulators are not permitted from day1 through day 28) symptoms of severe systemic illness/infection with covid-19: at least 1 of the following: fever, cough, sore throat, malaise, headache, muscle pain, shortness of breath at rest or with exertion, confusion, or symptoms of severe lower respiratory infection including dyspnea at rest or respiratory distress and clinical signs indicative of severe systemic illness/infection with covid-19 at least 1 of the following: rr ≥ 30, hr ≥ 125, sao2 \<93% on room air or requires \> 2l oxygen by nasal cannula in order to maintain sao2 ≥93% 4. patient (or legally authorized representative) provides written informed consent prior to initiation of any study procedures. 5. adequate hematopoietic capacity, as defined by the following: 1. hemoglobin ≥ 9.0 g/dl and not transfusion dependent 2. platelets ≥ 100,000/mm3 3. absolute neutrophil count ≥ 1500 cells/mm3 6. adequate hepatic function, as defined by the following: 1. ast and alt ≤ 2.5 times upper limit of normal (uln) 2. total bilirubin ≤ 1.5 x uln 3. albumin ≥ 3.0 g/dl 7. adequate renal function, as defined by the following: a. renal: calculated creatinine clearance \>45 ml/min for patients with abnormal, increased creatinine levels (cockcroft-gault formula). 8. ability to take oral medication and be willing to adhere to drug administration and premedication requirements (see section 6.3) throughout study duration.

inclusion criteria: 1. male or non-pregnant female adult ≥ 18 years of age 2. diagnosed/confirmed with covid-19 by standard rt-pcr assay or equivalent testing within 7 days prior to randomization (day1). 3. hospitalized patient with severe illness caused by sars-cov-2 (note: prior or current use of remdesivir or dexamethasone (soc) are allowed under the investigator's discretion. concomitant treatment with other investigational antiviral drugs or immunomodulators are not permitted from day1 through day 28) symptoms of severe systemic illness/infection with covid-19: at least 1 of the following: fever, cough, sore throat, malaise, headache, muscle pain, shortness of breath at rest or with exertion, confusion, or symptoms of severe lower respiratory infection including dyspnea at rest or respiratory distress and clinical signs indicative of severe systemic illness/infection with covid-19 at least 1 of the following: rr ≥ 30, hr ≥ 125, sao2 \<93% on room air or requires \> 2l oxygen by nasal cannula in order to maintain sao2 ≥93% 4. patient (or legally authorized representative) provides written informed consent prior to initiation of any study procedures. 5. adequate hematopoietic capacity, as defined by the following: 1. hemoglobin ≥ 9.0 g/dl and not transfusion dependent 2. platelets ≥ 100,000/mm3 3. absolute neutrophil count ≥ 1500 cells/mm3 6. adequate hepatic function, as defined by the following: 1. ast and alt ≤ 2.5 times upper limit of normal (uln) 2. total bilirubin ≤ 1.5 x uln 3. albumin ≥ 3.0 g/dl 7. adequate renal function, as defined by the following: a. renal: calculated creatinine clearance \>45 ml/min for patients with abnormal, increased creatinine levels (cockcroft-gault formula). 8. ability to take oral medication and be willing to adhere to drug administration and premedication requirements (see section 6.3) throughout study duration.

inclusion criteria: male or non-pregnant female adult ≥ 18 years of age diagnosed/confirmed with covid-19 by standard rt-pcr assay or equivalent testing within 7 days prior to randomization (day1). hospitalized patient with severe illness caused by sars-cov-2 (note: prior or current use of remdesivir or dexamethasone (soc) are allowed under the investigator's discretion. concomitant treatment with other investigational antiviral drugs or immunomodulators are not permitted from day1 through day 28) symptoms of severe systemic illness/infection with covid-19: at least 1 of the following: fever, cough, sore throat, malaise, headache, muscle pain, shortness of breath at rest or with exertion, confusion, or symptoms of severe lower respiratory infection including dyspnea at rest or respiratory distress and clinical signs indicative of severe systemic illness/infection with covid-19 at least 1 of the following: rr ≥ 30, hr ≥ 125, sao2 <93% on room air or requires > 2l oxygen by nasal cannula in order to maintain sao2 ≥93% patient (or legally authorized representative) provides written informed consent prior to initiation of any study procedures. adequate hematopoietic capacity, as defined by the following: hemoglobin ≥ 9.0 g/dl and not transfusion dependent platelets ≥ 100,000/mm3 absolute neutrophil count ≥ 1500 cells/mm3 adequate hepatic function, as defined by the following: ast and alt ≤ 2.5 times upper limit of normal (uln) total bilirubin ≤ 1.5 x uln albumin ≥ 3.0 g/dl adequate renal function, as defined by the following: a. renal: calculated creatinine clearance >45 ml/min for patients with abnormal, increased creatinine levels (cockcroft-gault formula). ability to take oral medication and be willing to adhere to drug administration and premedication requirements (see section 6.3) throughout study duration.

inclusion criteria: male or non-pregnant female adult ≥ 18 years of age diagnosed/confirmed with covid-19 by standard rt-pcr assay or equivalent testing within 7 days prior to randomization (day1). hospitalized patient with severe illness caused by sars-cov-2 (note: prior or current use of remdesivir or dexamethasone (soc) are allowed under the investigator's discretion. concomitant treatment with other investigational antiviral drugs or immunomodulators are not permitted from day1 through day 28) symptoms of severe systemic illness/infection with covid-19: at least 1 of the following: fever, cough, sore throat, malaise, headache, muscle pain, shortness of breath at rest or with exertion, confusion, or symptoms of severe lower respiratory infection including dyspnea at rest or respiratory distress and clinical signs indicative of severe systemic illness/infection with covid-19 at least 1 of the following: rr ≥ 30, hr ≥ 125, sao2 <93% on room air or requires > 2l oxygen by nasal cannula in order to maintain sao2 ≥93% patient (or legally authorized representative) provides written informed consent prior to initiation of any study procedures. adequate hematopoietic capacity, as defined by the following: hemoglobin ≥ 9.0 g/dl and not transfusion dependent platelets ≥ 100,000/mm3 absolute neutrophil count ≥ 1500 cells/mm3 adequate hepatic function, as defined by the following: ast and alt ≤ 2.5 times upper limit of normal (uln) total bilirubin ≤ 1.5 x uln albumin ≥ 3.0 g/dl adequate renal function, as defined by the following: a. renal: calculated creatinine clearance >45 ml/min for patients with abnormal, increased creatinine levels (cockcroft-gault formula). ability to take oral medication and be willing to adhere to drug administration and premedication requirements (see section 6.3) throughout study duration.

inclusion criteria: 1. male or non-pregnant female adult ≥ 18 years of age 2. diagnosed/confirmed with covid-19 by standard rt-pcr assay or equivalent testing within 7 days prior to randomization (day1). 3. hospitalized patient with severe illness caused by sars-cov-2 (note: prior or current use of remdesivir or dexamethasone (soc) are allowed under the investigator's discretion. concomitant treatment with other investigational antiviral drugs or immunomodulators are not permitted from day1 through day 28) symptoms of severe systemic illness/infection with covid-19: at least 1 of the following: fever, cough, sore throat, malaise, headache, muscle pain, shortness of breath at rest or with exertion, confusion, or symptoms of severe lower respiratory infection including dyspnea at rest or respiratory distress and clinical signs indicative of severe systemic illness/infection with covid-19 at least 1 of the following: rr ≥ 30, hr ≥ 125, sao2 <93% on room air or requires > 2l oxygen by nasal cannula in order to maintain sao2 ≥93% 4. patient (or legally authorized representative) provides written informed consent prior to initiation of any study procedures. 5. adequate hematopoietic capacity, as defined by the following: 1. hemoglobin ≥ 9.0 g/dl and not transfusion dependent 2. platelets ≥ 100,000/mm3 3. absolute neutrophil count ≥ 1500 cells/mm3 6. adequate hepatic function, as defined by the following: 1. ast and alt ≤ 2.5 times upper limit of normal (uln) 2. total bilirubin ≤ 1.5 x uln 3. albumin ≥ 3.0 g/dl 7. adequate renal function, as defined by the following: a. renal: calculated creatinine clearance >45 ml/min for patients with abnormal, increased creatinine levels (cockcroft-gault formula). 8. ability to take oral medication and be willing to adhere to drug administration and premedication requirements (see section 6.3) throughout study duration.

inclusion criteria: 1. male or non-pregnant female adult ≥ 18 years of age 2. diagnosed/confirmed with covid-19 by standard rt-pcr assay or equivalent testing within 7 days prior to randomization (day1). 3. hospitalized patient with severe illness caused by sars-cov-2 (note: prior or current use of remdesivir or dexamethasone (soc) are allowed under the investigator's discretion. concomitant treatment with other investigational antiviral drugs or immunomodulators are not permitted from day1 through day 28) symptoms of severe systemic illness/infection with covid-19: at least 1 of the following: fever, cough, sore throat, malaise, headache, muscle pain, shortness of breath at rest or with exertion, confusion, or symptoms of severe lower respiratory infection including dyspnea at rest or respiratory distress and clinical signs indicative of severe systemic illness/infection with covid-19 at least 1 of the following: rr ≥ 30, hr ≥ 125, sao2 <93% on room air or requires > 2l oxygen by nasal cannula in order to maintain sao2 ≥93% 4. patient (or legally authorized representative) provides written informed consent prior to initiation of any study procedures. 5. adequate hematopoietic capacity, as defined by the following: 1. hemoglobin ≥ 9.0 g/dl and not transfusion dependent 2. platelets ≥ 100,000/mm3 3. absolute neutrophil count ≥ 1500 cells/mm3 6. adequate hepatic function, as defined by the following: 1. ast and alt ≤ 2.5 times upper limit of normal (uln) 2. total bilirubin ≤ 1.5 x uln 3. albumin ≥ 3.0 g/dl 7. adequate renal function, as defined by the following: a. renal: calculated creatinine clearance >45 ml/min for patients with abnormal, increased creatinine levels (cockcroft-gault formula). 8. ability to take oral medication and be willing to adhere to drug administration and premedication requirements (see section 6.3) throughout study duration.