Inclusion Criteria

1. Not currently hospitalized

2. Males or females aged ≥ 18 years at the time of signing the informed consent form
(ICF)

3. Patients diagnosed with viral pneumonia, as determined by the investigator, who
exhibit any of the subsequent criteria: presence of respiratory symptoms or fever
(ear temperature ≥ 38 °C, base of the tongue temperature ≥ 37.5 °C, or axillary
temperature ≥ 37 °C)

4. With a pneumonia severity index (PSI) of risk class II or III

5. Oxygen saturation measured by pulse oximetry (SpO2) ≥ 94% on room air at sea level

6. Positive test for SARS-CoV-2 or influenza virus infection, confirmed by rapid
diagnostic test (excluding cases where both SARS-CoV-2 and influenza virus are
positive)

7. Confirmed lower respiratory tract infection by X-ray

8. At screening, subjects capable of childbearing must provide a negative serum or
urine pregnancy test. These subjects must also commit to adhering to the
study-specified contraceptive methods throughout the study duration

Notes: Acceptable contraceptive methods include:

- Established use of oral, injected or implanted hormonal methods of
contraception

- Placement of an intrauterine device (IUD) or intrauterine system (IUS)

- Barrier methods of contraception: condom or occlusive cap (diaphragm or
cervical/vault caps)

9. The participant (or legal representative) agrees and is able to adhere to study
protocol-stated requirements, instructions, and restrictions in the investigator's
judgement. Furthermore, the participant is capable of understanding and has signed
the IRB-approved Informed Consent Form (ICF)

10. With at least two of the risk factors listed below: Age ≥ 50 years-old; cancer and a
life expectancy of ≥ 6 months; HIV infection; immunocompromised patient; congestive
heart failure (CHF), or coronary artery disease (CAD), or cardiomyopathies; chronic
kidney disease (CKD); chronic liver disease; chronic lung disease; diabetes mellitus
(DM); body mass index (BMI) > 25 kg/m2; asthma; cerebrovascular disease; cystic
fibrosis; dementia; or current and former smoker

Exclusion Criteria

1. Subject received investigational treatment within 30 days prior to the study, or
concurrent use of another investigational drug

2. Subject has a history of severe renal disease (required phosphate binders or
dialysis)

3. Subject has chronic diarrhea, characterized by three or more loose stools daily for
a minimum of four weeks

4. High likelihood of mortality within the next 48 hours, as assessed by the
investigator

5. Subject showing signs of respiratory failure and mechanical ventilation is required

6. Subject with liver cirrhosis

7. Subject with hepatitis B and/or hepatitis C disease, unless the subject has an
aspartate aminotransferase (AST) level ranging from 8 to 31 U/L and an alanine
aminotransferase (ALT) level from 0 to 41 U/L

8. Known active tuberculosis

9. Current documented bacterial infection

10. Subject has a documented anaphylactic reaction, regardless of cause

11. Subject who has taken an antiviral agent against respiratory viral infection for a
continuous duration of more than 24 hours before screening

12. Subject is with active gastrointestinal diseases including gastritis, ulcerative
colitis, Crohn's disease, or hemorrhagic coloproctitis

13. Subjects received warfarin within 14 days prior to screening or intend to during the
screening or treatment phase

14. History of allergic reactions to any of the ingredients or components used in the
manufacture of CX-4945

15. Women who are pregnant or breastfeeding, or planning pregnancy during the study

Note: Men and women of reproductive potential must commit to effective contraception
methods or abstinence during the study. Any resulting pregnancies or suspected
pregnancies must be reported to the treating physician immediately.

16. ALT or AST levels > 5 times upper limit of normal (ULN)

17. eGFR <30 mL/min/1.73m2 (calculated by the MDRD formula)

18. Absolute neutrophil count (ANC) <1000/μL

19. Have received treatment with a SARS-CoV-2 specific monoclonal antibody

20. Have received convalescent COVID-19 plasma treatment

21. Concurrent use of baricitinib

22. Any physical findings or illness history that may compromise study results or
increase patient risk, as determined by the investigator