Study to Evaluate the Safety and Efficacy of Liquid Alpha1-Proteinase Inhibitor (Human) in Hospitalized Participants With Coronavirus Disease (COVID-19)

Inclusion Criteria:

1. Hospitalized male or female participant ≥ 18 years of age at time of screening who is
being treated for COVID-19. Participants must be screened within 48 hours (≤ 48 hours)
of hospital admission.

2. Has laboratory-confirmed novel coronavirus {SARS-CoV-2} infection as determined by
qualitative polymerase chain reaction (PCR) (reverse transcriptase [RT]-PCR), or other
commercial or public health assay approved by regulatory authorities as a diagnostic
test for COVID-19 in any specimen during the current hospital admission OR 96 hours
prior to the hospital admission date and prior to randomization (the SARS-CoV-2 test
results must be performed by a hospital laboratory and the documentation available).

3. COVID-19 illness (symptoms) of any duration, including both of the following: a)
Radiographic infiltrates by imaging (chest X-Ray, computed tomography (CT) scan, etc.)
and/or clinical assessment (evidence of rales/crackles on exam) with peripheral oxygen
saturation by pulse oximetry (SpO2) <94% on room air; b) Any one of the following
related to COVID-19: i. Ferritin > 400 nanogram per milliliter (ng/mL), ii. lactate
dehydrogenase (LDH) > 300 units per liter (U/L), iii. D-Dimers > reference range, or
iv. C-reactive protein (CRP) > 40 milligram per liter (mg/L).

4. Participant provides informed consent prior to initiation of any study procedures.

5. Female participants of childbearing potential (and males with female partners of
childbearing potential) must agree to use of acceptable contraception methods during
study (example, oral, injectable, or implanted hormonal methods of contraception,
placement of an intrauterine device or intrauterine system, condom or occlusive cap
with spermicidal foam/gel/film/cream/suppository, male sterilization, or true
abstinence) throughout the study.

Exclusion Criteria:

1. Participants requiring invasive mechanical ventilation or ICU admission or with
partial pressure of arterial oxygen/ fraction of inspired oxygen (PaO2/FIO2) ≤ 150
mmHg (i.e., arterial oxygen in millimeter of mercury (mmHg) divided by fraction
inspired oxygen concentration [example, 0.21 for room air]).

2. Clinical evidence of any significant acute or chronic disease that, in the opinion of
the investigator, may place the participant at undue medical risk.

3. The participant has had a known serious anaphylactic reaction to blood, any
blood-derived or plasma product, or known selective immunoglobulin A (IgA) deficiency
with anti-IgA antibodies.

4. A medical condition in which the infusion of additional fluid is contraindicated
(example, decompensated congestive heart failure or renal failure with fluid
overload). This includes currently uncontrolled congestive heart failure New York
Heart Association Class III or IV stage heart failure.

5. Shock that is unresponsive to fluid challenge and/or multiple vasopressors and
accompanied by multiorgan failure considered not able to be reversed by the Principal
Investigator.

6. Known alpha-1 antitrypsin deficiency for which the participant is already receiving
alpha1-proteinase inhibitor augmentation therapy.

7. Women who are pregnant or breastfeeding. Female participants of child-bearing
potential must have a negative test for pregnancy blood or urine human chorionic
gonadotropin (HCG)-based assay at screening/baseline visit.

8. Participants for whom there is limitation of therapeutic effort such as "Do not
resuscitate" status.

9. Currently participating in another interventional clinical trial with investigational
medical product or device.

10. Participants previously requiring long-term oxygen therapy (home oxygen therapy).

11. History (within the last 2 years) of myocardial infarction, unstable angina, stroke or
transient ischemic attacks, pulmonary embolism or deep venous thrombosis.

12. Participant has medical condition (other than COVID-19) that is projected to limit
lifespan to ≤ 1 year.

13. Systolic blood pressure < 100 mm Hg or > 160 mm Hg (uncontrolled hypertension) at the
time of Screening.

14. Alanine aminotransferase (ALT) ≥ 2 times the upper limit of normal (ULN).

15. Any elevation of total bilirubin at the time of Screening.

16. Estimated glomerular filtration rate (eGFR) < 45 mL/min (or participant is dependent
on dialysis/renal replacement therapy) at the time of Screening. eGFR is calculated by
the Cockcroft-Gault equation.

17. Hemoglobin < 10 g/dL at the time of Screening.

18. Absolute neutrophil count < 1000/mm^3 at the time of Screening.

19. Platelet count < 75,000/mm^3 at the time of Screening.

20. Participant has history of drug or alcohol abuse within the past 24 months.

21. Participant is unwilling to commit to follow-up visits.

22. Known history of prothrombin gene mutation 20210, homozygous Factor V Leiden
mutations, antithrombin III deficiency, protein C deficiency, protein S deficiency or
antiphospholipid syndrome.