• 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

• 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.

• Age ≥18 years

• Informed consent obtained from subject/next of kin/legal proxy

• 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

• During the course of the study starting at screening and for at least 3 months after their final study treatment:

∙ Female subjects of childbearing potential must agree to use 2 medically accepted and approved birth control methods

‣ 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

‣ All subjects must agree not to donate sperm or eggs