Inclusion Criteria:

- Confirmed laboratory diagnosis of SARS-CoV2 by standard FDA-approved reverse
transcription polymerase chain reaction (RT-PCR) assay or equivalent FDA-approved
testing (local labs).

- Currently hospitalized.

- Informed consent provided as above (it is recommended that participants are dosed with
study drug within 12 hours of consent).

- Has symptoms of severe COVID-19 as demonstrated by:

- At least one 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 symptoms including dyspnea at rest or respiratory
distress.

- Clinical signs indicative of lower respiratory infection with COVID-19, with at
least one of the following: SaO2 <92% on room air in last 12 hours or requires >
4 liters per minute (LPM) oxygen by nasal canula, non-rebreather/Ventimask or
high flow nasal canula in order maintain SaO2 ≥92%, PaO2/FiO2 <300 millimeter per
mercury (mm/hg).

- Elevated C-reactive protein (CRP) > 2 x upper limit of normal (ULN).

- Concurrent anti-viral and/or anti-inflammatory agents (e.g., biologics,
hydroxychloroquine) are permitted. If in the physician's judgment, it is in the best
interest of the participant to use anti-viral or anti-inflammatory treatments, these
treatments are to be documented in the participant's chart and entered in the
electronic case report form.

- Female participants of childbearing potential must have a negative serum pregnancy
test at Screening. Female participants of childbearing potential and fertile male
participants must use highly effective methods of contraception throughout the study
and for 3 months following the last dose of study treatment.

Exclusion Criteria:

- Evidence of critical COVID-19 based on:

- Respiratory failure (defined by endotracheal intubation and mechanical
ventilation, oxygen delivered by noninvasive positive pressure ventilation, or
clinical diagnosis of respiratory failure in setting of resource limitations)

- Septic shock (defined by Systolic blood pressure [BP] < 90 mm Hg, or Diastolic BP
< 60 mm Hg)

- Multiple organ dysfunction/failure

- In the opinion of the investigator, unlikely to survive for at least 48 hours from
screening or anticipate mechanical ventilation within 48 hours.

- Inadequate hematologic parameters as indicated by the following labs:

- Participants with severe neutropenia (ANC <1000 x 10^9/L) or

- Thrombocytopenia (e.g., platelets <100,000 per microliter of blood)

- Inadequate renal and liver function as indicated by the following labs:

- Creatinine clearance (CrCL) <20 mL/min using the formula of Cockcroft and Gault

- Aspartate transaminase (AST) or alanine transaminase (ALT) > 5 x ULN

- Hyponatremia defined as sodium < 135 milliequivalents per liter (mEq/L).

- Unable to take oral medication when informed consent is obtained.

- Participants with a legal guardian or who are incarcerated.

- Treatment with strong CYP3A inhibitors or inducers.

- Pregnant and breastfeeding women.