Rhu-pGSN for Acute Respiratory Distress Syndrome (ARDS)

Inclusion Criteria: 1. Infection followed within a week of documented bilateral infiltrates/opacities consistent with ARDS, as assessed by the admitting emergency department, clinic, intensivist, or ward physician or equivalent caregiver or a radiologist * Investigator or designee to note radiologic findings in the electronic case report form (eCRF) * Radiology report and conclusion should be summarized in the eCRF * A digital copy of the radiograph uploaded and saved for review 2. Acute hypoxemic respiratory failure (moderate-to-severe ARDS) for ≤48 hours associated with suspected or confirmed infection (moderate-to-severe ARDS defined by the ratio of arterial pressure of O2 to the fraction of inspired O2 ≤150). Eligible subjects will be intubated for mechanical ventilation, receiving noninvasive ventilation by continuous positive airway pressure (CPAP) or bilevel positive airway pressure (BiPAP), or on HFNO at least 30 L/min of 50% or greater inspired O2. Although it is expected that most eligible subjects will be receiving positive end-expiratory pressure (PEEP) or CPAP ≥5 cm H2O consistent with the original Berlin definition (ARDS Definition Task Force 2012), these measures will not be mandated as entry criteria. 3. Age ≥18 years 4. Informed consent obtained from subject/next of kin/legal proxy 5. Clear or convincing evidence of a precipitating infection during the 7 days preceding the diagnosis of ARDS in the judgement of the screening or primary care team 6. During the course of the study starting at screening and for at least 3 months after their final study treatment: 1. Female subjects of childbearing potential must agree to use 2 medically accepted and approved birth control methods 2. Male subjects with a partner who might become pregnant must agree to use reliable forms of contraception (i.e., vasectomy, abstinence), or an acceptable method of birth control must be used by the partner 3. All subjects must agree not to donate sperm or eggs Exclusion Criteria: 1. Ongoing evidence or suspicion that heart failure, volume overload, pulmonary emboli, atelectasis, chronic lung disease, pleural effusion, cardiac tamponade, or constrictive pericarditis are materially contributing to the clinical or radiological findings bas assessed by the care team or Investigator; an echocardiogram is strongly recommended as part of standard care to exclude a significant contribution of systolic or diastolic heart failure and volume overload. 2. Presence of systemic fungal, yeast, parasitic, or mycobacterial infection 3. Current or planned receipt of extracorporeal membrane oxygenation (ECMO) 4. Pregnant or lactating women 5. Previous splenectomy 6. Any vaccination in the previous 30 days 7. Participation in an investigational clinical trial (e.g., device, drug, or biologic) in the previous 30 days 8. Known allergy to study drug or excipients 9. Weight \>125 kg 10. Active underlying cancer or treatment with systemic chemotherapy or radiation therapy during the last 60 days or likely to require similar treatments during the ensuing 6 months 11. Transplantation of hematopoietic or solid organs, graft versus host disease, or post-transplant lymphoproliferative disease 12. Chronic mechanical ventilation or dialysis 13. Unsuitable for study participation, in the opinion of the Investigator, because of chronic, severe, end-stage, or life-limiting underlying disease unrelated to current infection likely to interfere with management and assessment of ARDS, only comfort or limited (non-aggressive) care is to be given, or life expectancy \<6 months unrelated to acute infection in the opinion of the Investigator.