Multiple Dosing of Mesenchymal Stromal Cells in Patients With ARDS (COVID-19)

Inclusion Criteria: * Age 18-80 years * Meets 'Berlin Criteria' for diagnosis of moderate to severe ARDS for a minimum of 4 hours * Less than 48 hours on a ventilator after meeting criteria for diagnosis of ARDS * SARS-CoV-2 (proven by RT-PCR assay) with radiographic infiltrates * PaO2/FiO2 \< 250 * Positive end-expiratory airway pressure (PEEP) \>5 cm H20 * Elevated C-reactive protein (above laboratory upper limit of normal) * Meets organ function requirements, including left ventricular ejection fraction (LVEF) \>35% ( as defined below) * Off other investigational agents directed against inflammatory cytokines 48 hours prior to enrollment; agents directed against the replication of SARS-CoV-2 \[e.g., Remdesivir\] are permitted * Voluntary informed consent in person or virtually by the patient or patient surrogate considering the face to face limitations during the COVID-19 pandemic and, given the nature of the study population, which frequently requires mechanical ventilation with sedation, surrogate consent will likely occur in a substantial proportion of the study population (this will remain a valid consent until the patient is fully alert, and aware, and can provide a second consent to continue participation in the study). * Adequate organ function is defined as: * Renal: Calculated estimated glomerular filtration rate \>30 mL/min/1.73 m2 (on chemistry panel) * Hepatic: Bilirubin \<3x upper limit of normal (ULN) and AST, ALT and alkaline phosphatase \<5x ULN * Cardiac: Absence of uncontrolled arrhythmia and LVEF \>35% Exclusion Criteria: * Ventilator support of FiO2 \>0·8 or PEEP \>20 cm H2O and ongoing use of more than two vasopressors for 2 or more hours with any agent at doses shown below in the supine position. * Norepinephrine \>12 μg/min or 0.2 μg/kg per min * Phenylephrine \>150 μg/min or 3 μg/kg per min * Epinephrine \>10 ug/min or 0.2 μg/kg per min * Vasopressin \>0.04 units/min * Concurrent use of other investigational agents specifically for treatment of ARDS or inflammatory cytokines. (Note: Agents established to be efficacious and/or those used outside of formal trials are permitted as supportive data emerge) * Known ineligibility for use of a ventilator for a minimum of 7 days, as judged by the institution's Triage Team * Known allergy to MSC components: fetal calf serum, human albumin or DMSO * Active invasive malignant disease requiring chemotherapy/radiation * Other concurrent life-threatening disease (life expectancy \<6 months) or eligible for hospice care * Known history of HIV infection on active treatment * Females who are pregnant or breastfeeding * Current mean arterial pressure (MAP) \<60 mmHg while on 2 or more vasopressors at above doses for more than 2 hours * History of any significant cardiac (myocardial infarction within 12 months of screening visit or unstable angina), chronic ongoing hepatic, or renal disease (grade 3 or higher); diagnosis of congestive heart failure with hypoxemia primarily due to decompensated heart failure; diagnosis of severe chronic obstructive pulmonary disease (COPD) or interstitial lung disease requiring supplemental oxygen at home * Concurrent diagnosis of diffuse alveolar hemorrhage * Requiring continuous dialysis (unable to stop dialysis during study agent infusion)