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CompletedNCT03818854STATUpdated Dec 4, 2025Results posted

Mesenchymal Stromal Cells For Acute Respiratory Distress Syndrome

A Phase 2 interventional study of Human Mesenchymal Stromal Cells and Cell Reconstitution Media in Respiratory Distress Syndrome, Adult, sponsored by Michael A. Matthay. Completed at 7 sites in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2025-12-04.

Sponsored by Michael A. Matthay · Phase 2, Interventional, and Treatment

Phase
Phase 2
Study type
Interventional
Enrollment
120
Allocation
Randomized
Ages
18 Years and older
Sex
All
01

Study summary

This is a Phase 2b, randomized, double-blind, placebo-controlled, multi-center study to assess the safety and efficacy of a single dose of Allogeneic Bone Marrow-derived Human Mesenchymal Stromal Cells (hMSCs) infusion in patients with Acute Respiratory Distress Syndrome (ARDS). This study is the extension of the Phase 1 pilot study (NCT01775774) and Phase 2a study (NCT02097641).

Read the detailed description

This clinical study design is a randomized, double-blinded, placebo-controlled Phase 2b clinical trial using a 10 million cell/kg dose of human Mesenchymal Stromal Cells (hMSCs). Subjects will be randomized in a 1:1 randomization scheme to receive hMSCs or cell reconstitution media (1:1 mix of 5% human serum albumin and 10% Dextran 40) as the placebo; the study will enroll 120 patients who achieve a stable clinical baseline and receive study product (either hMSCs or the placebo).

The Data and Safety Monitoring Board (DSMB) will review adverse outcomes and protocol compliance. A pre-specified interim review will occur after 60 subjects have been enrolled and received study product; enrollment will continue during the DSMB review. All pre-specified clinically important events and unexpected serious adverse events including death during hospitalization up to 60 days will be reported to the DSMB on an ongoing basis; the study will be stopped for a safety evaluation by the DSMB if they have any concerns or if three subjects have pre-specified clinically important events or unexpected serious adverse events except death since death will be common in this critically ill population due the nature of the underlying illness (e.g., ARDS).

02

Conditions studied

  • Respiratory Distress Syndrome, Adult

Keywords

  • Human Mesenchymal Stromal Cells
  • Acute Respiratory Distress Syndrome
03

In context

Respiratory Distress Syndrome

1,597 studies on the registry are indexed under Respiratory Distress Syndrome; 312 are open to participants now.

This study's enrollment of 120 is above the median of 60 across 961 interventional studies indexed under Respiratory Distress Syndrome.

Browse Respiratory Distress Syndrome studies →

Lead sponsor

Michael A. Matthay is the lead sponsor of 3 studies on the registry; none are open to participants now.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years and older
Sexes eligible
All
Accepts healthy volunteers
No

Inclusion criteria

Patients will be eligible for inclusion if they meet all of the below criteria within 14 days of initial ICU admission. Criteria 1-3 must all be present within a 24-hour time period and at the time of enrollment:

Acute onset (defined below) of:

  1. A need for positive pressure ventilation by an endotracheal or tracheal tube with a PaO2/FiO2 ratio \<250 mmHg and ≥5 cm H2O positive end-expiratory airway pressure (PEEP), as per the Berlin Criteria.
  2. Bilateral infiltrates consistent with pulmonary edema (defined below) on the frontal chest radiograph, or bilateral ground glass opacities on a chest CT scan.
  3. No clinical evidence of left atrial hypertension as a primary explanation for the bilateral pulmonary infiltrates.
  4. If the cause of ARDS is trauma, additional inclusion criteria will include ONE of the following relevant risk factors for developing ARDS:

    1. Hypotension (systolic blood pressure[SBP] \< 90 mmHg) in the field or in the first 24 h after injury, or
    2. Transfusion of 3 units of blood products in the first 24 hours following injury, or
    3. Meets the new Critical Administration Threshold (CAT) criteria with at least 3 units of blood in one hour, or
    4. Blunt or penetrating torso trauma, or
    5. Long bone fractures, or
    6. The highest level of institutional trauma activation

Exclusion criteria

Exclusion Criteria:

  1. Age less than 18 years
  2. Greater than 72 hours since first meeting ARDS criteria per the Berlin definition of ARDS
  3. Greater than 14 days since initial ICU admission
  4. Inability to administer study product within 14 days of ICU admission
  5. PaO2/FiO2 ≥ 250 mmHg after consent obtained and before study product is administered
  6. Unable to obtain informed consent/no surrogate available
  7. Pregnant or lactating
  8. In custody of law enforcement officials
  9. Burns > 20% of total body surface area
  10. WHO Class III or IV pulmonary hypertension
  11. History of cancer treatment in the last 2 years except for non-melanotic skin cancers
  12. Underlying medical condition for which 6-month mortality is estimated to be > 50%
  13. Moribund patient not expected to survive 24 hours
  14. Advanced chronic liver disease (Child-Pugh Score > 12)
  15. Severe chronic respiratory disease with the use of home oxygen
  16. Severe traumatic brain injury - defined as:

    1. A patient who has undergone intracranial neurosurgical intervention for monitoring or therapy (intracranial pressure monitoring, external ventricular drain, craniotomy), or
    2. Intracranial injury by head CT (does not include patients with minimal subarachnoid injury and/or minor skull fracture), or
    3. Post-resuscitation Glasgow Coma Score (GCS) \< 9 assessed after sedation interruption, or
    4. Non-survivable head injury as assessed by neurosurgery
  17. Evidence of anoxic brain injury
  18. History of stroke within the last 3 years
  19. No intent/unwillingness to follow lung protective ventilation strategy
  20. Currently receiving extracorporeal life support (ECLS) or high-frequency oscillatory ventilation (HFOV)
  21. Anticipated extubation within 24 hours of enrollment
  22. Clinical evidence of left atrial hypertension as measured by a pulmonary arterial wedge pressure > 18mmHg or left ventricular failure measured by an echocardiogram with a left ventricular ejection fraction less than 40%. Clinical judgement will determine if either of these measurements needs to be carried out.
05

Study design

Phase
Phase 2
Primary purpose
Treatment
Allocation
Randomized
Intervention model
Parallel assignment
Masking
Triple (Participant, Care provider, Investigator)
Enrollment
120 participants (actual)

Study arms

  • Experimental
    Human Mesenchymal Stromal Cells

    A single dose of 10 million cells/kg predicted body weight (PBW) Allogeneic Bone Marrow-Derived Human Mesenchymal Stromal Cells will administered intravenously over approximately 60-80 minutes.

    Biological: Human Mesenchymal Stromal Cells

  • Experimental
    Cell Reconstitution Media

    A single dose of cell reconstitution media (1:1 mix of 5% human serum albumin and 10% Dextran 40) will administered intravenously over approximately 60-80 minutes.

    Biological: Cell Reconstitution Media

Interventions

  • BiologicalHuman Mesenchymal Stromal Cells

    Immediately prior to administration, the study product will be thawed and diluted 1:1 with reconstitution media (1:1 mix of 5% human serum albumin and 10% Dextran 40). Additional reconstitution media is added to a final product volume of 300 mL.

    Also known as: hMSCs

  • BiologicalCell Reconstitution Media

    300 mL of reconstitution media (1:1 mix of 5% human serum albumin and 10% Dextran 40)

    Also known as: Placebo

06

What researchers measure

Primary outcomes

  1. Change in Oxygenation Index (OI)

    Change in OI from baseline over the 36 hours (6, 12, 18, 24, 30, 36 hours) following the initiation of the study product infusion. Lower values are considered better.

    Time frame: 36 hours

Secondary outcomes

  1. Acute Lung Injury Score (LIS)

    Changes in the 4-point acute lung injury (LIS) score from the baseline to days 1, 2, 3 and 7, or on the last day of positive pressure ventilation prior to day 7. The LIS is a composite 4-point scoring system including the PaO2/FiO2, PEEP, lung compliance, and the extent of infiltrates on the chest X-ray. Each of the four components is categorized from 0 to 4, where a higher number is worse. The total Lung Injury Score is obtained by dividing the aggregate sum by the number of components used.

    Time frame: 7 days

  2. Pulmonary Dead Space Fraction

    Pulmonary Dead Space at day 1, 2, 3 and 7. The dead-space fraction is calculated as: (PaCO2 - PeCO2) ÷ PaCO2

    Time frame: 7 days

  3. Change of Chest Radiograph Assessment of Pulmonary Edema (RALE Score)

    Changes of RALE score at day 1, 2, 3 and 7 from baseline RALE score. To calculate RALE, each radiographic quadrant is scored for extent of consolidation (0-4) and density of opacification (1-3). The product of the consolidation and density scores for each of the four quadrants is summed. The RALE score ranges from 0 (best) to 48 (worst).

    Time frame: 7 days

  4. Ventilator Free-days (VFD) Over 14 Days

    Ventilator free-days over 14 days. Defined as the number of days from the time of initiating unassisted breathing to day 14 after study product administration, assuming survival for at least two consecutive calendar days after initiating unassisted breathing and continued unassisted breathing to day 14. If a patient returns to assisted breathing and subsequently achieves unassisted breathing to day 14, VFDs will be counted from the end of the last period of assisted breathing to day 14.

    Time frame: 14 days

  5. Ventilator Free-days (VFD) Over 28 Days.

    Defined as the number of days from the time of initiating unassisted breathing to day 28 after study product administration, assuming survival for at least two consecutive calendar days after initiating unassisted breathing and continued unassisted breathing to day 28. If a patient returns to assisted breathing and subsequently achieves unassisted breathing to day 28, VFDs will be counted from the end of the last period of assisted breathing to day 28.

    Time frame: 28 days

  6. Duration of Assisted Ventilation Over 28 Days

    Duration of assisted ventilation over 28 days in the survivors

    Time frame: 28 days

  7. Percentage of Patients Achieving Pressure Support Ventilation for 2 Hours

    Percentage of patients achieving pressure support ventilation equal to 5 cm H2O with positive end-expiratory pressure (PEEP) equal to 5 cm H2O for 2 hours

    Time frame: 28 days

  8. Occurrence of Infection

    Superficial incisional/wound infections, deep incisional wound infections, and organ/space infections, and ventilator associated pneumonia (all during the 14 days after enrollment)

    Time frame: 14 days

  9. Occurrence of Thromboembolic Events

    Thromboembolic events are measured by ultrasound of the deep venous system or CT-angiography of the chest ordered for clinical purposes/by treating clinicians

    Time frame: 60 days

  10. Sequential Organ Failure Assessment (SOFA) Over 7 Days

    SOFA score at 3 and 7 days. The score is based on six different scores, one each for the respiratory, cardiovascular, hepatic, coagulation, renal and neurological systems which are added up. Each score ranges from 0 to 4. SOFA score ranges from 0 (best) to 24 (worst).

    Time frame: 7 days

  11. Non-pulmonary Sequential Organ Failure Assessment (SOFA) Over 7 Days

    Non-pulmonary SOFA score at 3 and 7 days. The score is based on 5 different scores, one each for the cardiovascular, hepatic, coagulation, renal and neurological systems which are added up. Each score ranges from 0 to 4. SOFA score ranges from 0 (best) to 20 (worst).

    Time frame: 7 days

  12. All-cause Mortality

    All-cause mortality at 14, 28 and 60 days

    Time frame: 60 days

  13. Glasgow Outcome Score (GCS)

    Glasgow Outcome Score at hospital discharge. The GCS is a scale to evaluate level of consciousness in patients with acute brain injury. The scale assesses 3 functions: Eye Opening, Verbal Response, and Motor Response. GCS scores range from 15 (best) to 3 (worst)

    Time frame: 60 days

  14. Plasma Angiopoietin-2

    Change in levels of plasma angiopoietin-2 from baseline at 6, 24, 48 and 72 hours since the initiation of the study product infusion.

    Time frame: 72 hours

  15. Plasma Receptor for Advanced Glycation Endproducts (RAGE)

    Change in levels of plasma RAGE from baseline at 6, 24, 48 and 72 hours since the initiation of the study product infusion.

    Time frame: 72 hours

  16. Plasma Interleukin-6 (IL-6)

    Change in levels of plasma interleukin-6 from baseline compared to 6, 24, 48 and 72 hours

    Time frame: 72 hours

  17. Plasma Interleukin-8 (IL-8)

    Change in levels of plasma interleukin-8 from baseline at 6, 24, 48 and 72 hours since the initiation of study product infusion.

    Time frame: 72 hours

  18. Plasma Tumor Necrosis Factor Receptor 1 (TNFR-1)

    Change in levels of plasma TNFR-1 from baseline at 6, 24, 48 and 72 hours since the initiation of study product infusion.

    Time frame: 72 hours

  19. Plasma Protein C

    Change in levels of plasma protein C from baseline at 6, 24, 48 and 72 hours since the initiation of study product infusion.

    Time frame: 72 hours

  20. Plasma Angiopoietin-1 (ANG-1)

    Change in levels of plasma angiopoietin-1 from the baseline to 6, 24, 48 and 72 hours since the initiation of study product infusion.

    Time frame: 72 hours

  21. Plasma Lipoxin A4

    Change in levels of plasma lipoxin A4 from baseline compared to 6, 24, 48 and 72 hours

    Time frame: 72 hours

  22. Plasma Resolvin D1

    Change in levels of plasma Resolvin D1 from baseline compared to 6, 24, 48 and 72 hours

    Time frame: 72 hours

  23. Plasma Keratinocyte Growth Factor (KGF)

    Change in levels of plasma KGF from baseline at 6, 24, 48 and 72 hours since the initiation of study product infusion.

    Time frame: 72 hours

  24. Urine Microalbumin

    Change in levels of urine microalbumin from baseline compared to 24 and 48 hours

    Time frame: 48 hours

  25. Total Protein in Min-bronchoalveolar Lavage (mBAL)

    Change in total protein levels in from baseline to day 2

    Time frame: 2 days

  26. Tolerability of the hMSCs - Incidence of Pre-specified Infusion-associated Events and Unexpected Severe Adverse Events

    Tolerability of the hMSCs, defined as the incidence of pre-specified infusion-associated events and unexpected severe adverse events in ARDS patients treated with human MSCs

    Time frame: 24 hours

07

Results

Posted Dec 4, 2025

Participant flow

Participant flow — Overall Study
MilestoneHuman Mesenchymal Stromal CellsCell Reconstitution Media
Started5961
Completed5961
Not completed00

Outcome measures

PrimaryChange in Oxygenation Index (OI)

Change in OI from baseline over the 36 hours (6, 12, 18, 24, 30, 36 hours) following the initiation of the study product infusion. Lower values are considered better.

Time frame:
36 hours
Reported as:
Median · cmH20/mmHg
Change in Oxygenation Index (OI)
cmH20/mmHgHuman Mesenchymal Stromal CellsCell Reconstitution Media
6 Hour-0.7 (-2.7 to 1.4)-1.5 (-3.0 to 1.0)
12 Hour0.8 (-1.6 to 3.5)-1.1 (-3.9 to 0.9)
18 Hour0.3 (-3.4 to 3.5)-1.0 (-4.1 to 2.5)
24 Hour0.3 (-3.7 to 5.9)-1.1 (-4.2 to 2.2)
30 Hour0.8 (-3.3 to 3.8)-0.7 (-4.0 to 1.0)
36 Hour0.8 (-3.5 to 5.0)-1.5 (-3.9 to 0.9)
Statistical analysis
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Mixed Models Analysis · p = 0.34 (The mixed model included the following variables: treatment arm, 6 time-points, sites, pre-defined randomization stratifications and the baseline characteristics with bivariate analyses P \< 0.20.)
SecondaryAcute Lung Injury Score (LIS)

Changes in the 4-point acute lung injury (LIS) score from the baseline to days 1, 2, 3 and 7, or on the last day of positive pressure ventilation prior to day 7. The LIS is a composite 4-point scoring system including the PaO2/FiO2, PEEP, lung compliance, and the extent of infiltrates on the chest X-ray. Each of the four components is categorized from 0 to 4, where a higher number is worse. The total Lung Injury Score is obtained by dividing the aggregate sum by the number of components used.

Time frame:
7 days
Reported as:
Mean · score on a scale
Acute Lung Injury Score (LIS)
score on a scaleHuman Mesenchymal Stromal CellsCell Reconstitution Media
Day 1-0.10 ± 0.41-0.10 ± 0.48
Day 2-0.07 ± 0.41-0.15 ± 0.62
Day 3-0.15 ± 0.53-0.09 ± 0.57
Day 7-0.39 ± 0.69-0.21 ± 0.63
Statistical analysis
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · t-test, 2 sided · p = 0.92
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · t-test, 2 sided · p = 0.37
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · t-test, 2 sided · p = 0.54
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · t-test, 2 sided · p = 0.19
SecondaryPulmonary Dead Space Fraction

Pulmonary Dead Space at day 1, 2, 3 and 7. The dead-space fraction is calculated as: (PaCO2 - PeCO2) ÷ PaCO2

Time frame:
7 days

No measurements were reported for this outcome.

SecondaryChange of Chest Radiograph Assessment of Pulmonary Edema (RALE Score)

Changes of RALE score at day 1, 2, 3 and 7 from baseline RALE score. To calculate RALE, each radiographic quadrant is scored for extent of consolidation (0-4) and density of opacification (1-3). The product of the consolidation and density scores for each of the four quadrants is summed. The RALE score ranges from 0 (best) to 48 (worst).

Time frame:
7 days
Reported as:
Median · score on a scale
Change of Chest Radiograph Assessment of Pulmonary Edema (RALE Score)
score on a scaleHuman Mesenchymal Stromal CellsCell Reconstitution Media
Day 1-0.7 (-3.3 to 2.9)1.0 (-2.5 to 5.0)
Day 2-1.1 (-5.8 to 4.3)1.7 (-2.7 to 4.5)
Day 3-0.5 (-4.7 to 4.3)0.0 (-3.4 to 4.0)
Day 7-2.3 (-9.3 to 5.7)2.4 (-1.7 to 8.0)
Statistical analysis
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Wilcoxon (Mann-Whitney) · p = 0.35
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Wilcoxon (Mann-Whitney) · p = 0.25
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Wilcoxon (Mann-Whitney) · p = 0.69
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Wilcoxon (Mann-Whitney) · p = 0.08
SecondaryVentilator Free-days (VFD) Over 14 Days

Ventilator free-days over 14 days. Defined as the number of days from the time of initiating unassisted breathing to day 14 after study product administration, assuming survival for at least two consecutive calendar days after initiating unassisted breathing and continued unassisted breathing to day 14. If a patient returns to assisted breathing and subsequently achieves unassisted breathing to day 14, VFDs will be counted from the end of the last period of assisted breathing to day 14.

Time frame:
14 days
Reported as:
Count of participants · Participants
Ventilator Free-days (VFD) Over 14 Days
ParticipantsHuman Mesenchymal Stromal CellsCell Reconstitution Media
0 day4432
1 - 4 days47
5 - 9 days712
10 - 13 days410
Statistical analysis
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Regression, Logistic · p = 0.01 (P-value was given by ordered logistic regression model.)
SecondaryVentilator Free-days (VFD) Over 28 Days.

Defined as the number of days from the time of initiating unassisted breathing to day 28 after study product administration, assuming survival for at least two consecutive calendar days after initiating unassisted breathing and continued unassisted breathing to day 28. If a patient returns to assisted breathing and subsequently achieves unassisted breathing to day 28, VFDs will be counted from the end of the last period of assisted breathing to day 28.

Time frame:
28 days
Reported as:
Count of participants · Participants
Ventilator Free-days (VFD) Over 28 Days.
ParticipantsHuman Mesenchymal Stromal CellsCell Reconstitution Media
0 day3627
1-9 days64
10-15 days31
15-19 days612
20-24 days610
25-27 days27
Statistical analysis
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Regression, Logistic · p = 0.02 (P-value was given by ordered logistic regression model.)
SecondaryDuration of Assisted Ventilation Over 28 Days

Duration of assisted ventilation over 28 days in the survivors

Time frame:
28 days
Reported as:
Median · days
Duration of Assisted Ventilation Over 28 Days
daysHuman Mesenchymal Stromal CellsCell Reconstitution Media
Duration of Assisted Ventilation Over 28 Days22 (9 to 28)10 (5 to 20)
Statistical analysis
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Wilcoxon (Mann-Whitney) · p = 0.01
SecondaryPercentage of Patients Achieving Pressure Support Ventilation for 2 Hours

Percentage of patients achieving pressure support ventilation equal to 5 cm H2O with positive end-expiratory pressure (PEEP) equal to 5 cm H2O for 2 hours

Time frame:
28 days
Reported as:
Count of participants · Participants
Percentage of Patients Achieving Pressure Support Ventilation for 2 Hours
ParticipantsHuman Mesenchymal Stromal CellsCell Reconstitution Media
Yes2531
No3430
Statistical analysis
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Chi-squared · p = 0.35
SecondaryOccurrence of Infection

Superficial incisional/wound infections, deep incisional wound infections, and organ/space infections, and ventilator associated pneumonia (all during the 14 days after enrollment)

Time frame:
14 days
Reported as:
Count of participants · Participants
Occurrence of Infection
ParticipantsHuman Mesenchymal Stromal CellsCell Reconstitution Media
Incisional/wound infection31
Organ/space infection10
Ventilator associated pneumonia2014
Statistical analysis
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Fisher Exact · p = 0.36
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Fisher Exact · p = 0.50
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Fisher Exact · p = 0.20
SecondaryOccurrence of Thromboembolic Events

Thromboembolic events are measured by ultrasound of the deep venous system or CT-angiography of the chest ordered for clinical purposes/by treating clinicians

Time frame:
60 days
Reported as:
Count of participants · Participants
Occurrence of Thromboembolic Events
ParticipantsHuman Mesenchymal Stromal CellsCell Reconstitution Media
Occurrence of Thromboembolic Events108
Statistical analysis
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Chi-squared · p = 0.56 (The threshold for statistical significance was p=0.05.)
SecondarySequential Organ Failure Assessment (SOFA) Over 7 Days

SOFA score at 3 and 7 days. The score is based on six different scores, one each for the respiratory, cardiovascular, hepatic, coagulation, renal and neurological systems which are added up. Each score ranges from 0 to 4. SOFA score ranges from 0 (best) to 24 (worst).

Time frame:
7 days
Reported as:
Mean · score on a scale
Sequential Organ Failure Assessment (SOFA) Over 7 Days
score on a scaleHuman Mesenchymal Stromal CellsCell Reconstitution Media
Day 39.2 ± 3.18.6 ± 3.1
Day 78.5 ± 3.87.7 ± 4.8
Statistical analysis
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · t-test, 2 sided · p = 0.32
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · t-test, 2 sided · p = 0.33
SecondaryNon-pulmonary Sequential Organ Failure Assessment (SOFA) Over 7 Days

Non-pulmonary SOFA score at 3 and 7 days. The score is based on 5 different scores, one each for the cardiovascular, hepatic, coagulation, renal and neurological systems which are added up. Each score ranges from 0 to 4. SOFA score ranges from 0 (best) to 20 (worst).

Time frame:
7 days
Reported as:
Mean · score on a scale
Non-pulmonary Sequential Organ Failure Assessment (SOFA) Over 7 Days
score on a scaleHuman Mesenchymal Stromal CellsCell Reconstitution Media
Day 36.0 ± 3.25.5 ± 2.9
Day 75.6 ± 3.54.8 ± 3.8
Statistical analysis
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · t-test, 2 sided · p = 0.39
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · t-test, 2 sided · p = 0.26
SecondaryAll-cause Mortality

All-cause mortality at 14, 28 and 60 days

Time frame:
60 days
Reported as:
Count of participants · Participants
All-cause Mortality
ParticipantsHuman Mesenchymal Stromal CellsCell Reconstitution Media
14-day mortality128
28-day mortality1615
60-day mortality2118
Statistical analysis
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Chi-squared · p = 0.29 (The threshold for statistical significance was p=0.05)
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Chi-squared · p = 0.83
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Chi-squared · p = 0.56
SecondaryGlasgow Outcome Score (GCS)

Glasgow Outcome Score at hospital discharge. The GCS is a scale to evaluate level of consciousness in patients with acute brain injury. The scale assesses 3 functions: Eye Opening, Verbal Response, and Motor Response. GCS scores range from 15 (best) to 3 (worst)

Time frame:
60 days
Reported as:
Mean · score on a scale
Glasgow Outcome Score (GCS)
score on a scaleHuman Mesenchymal Stromal CellsCell Reconstitution Media
Glasgow Outcome Score (GCS)10.6 ± 5.611.5 ± 5.3
Statistical analysis
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · t-test, 2 sided · p = 0.41
SecondaryPlasma Angiopoietin-2

Change in levels of plasma angiopoietin-2 from baseline at 6, 24, 48 and 72 hours since the initiation of the study product infusion.

Time frame:
72 hours
Reported as:
Median · pg/mL
Plasma Angiopoietin-2
pg/mLHuman Mesenchymal Stromal CellsCell Reconstitution Media
6 hour125 (-807 to 1014)184 (-99 to 635)
24 hour407 (-1093 to 1733)288 (-966 to 1895)
48 hour879 (-200 to 2514)343 (-2622 to 2035)
72 hour594 (-1144 to 2318)544 (-3359 to 2219)
Statistical analysis
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Wilcoxon (Mann-Whitney) · p = 0.56
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Wilcoxon (Mann-Whitney) · p = 0.79
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Wilcoxon (Mann-Whitney) · p = 0.62
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Wilcoxon (Mann-Whitney) · p = 0.67
SecondaryPlasma Receptor for Advanced Glycation Endproducts (RAGE)

Change in levels of plasma RAGE from baseline at 6, 24, 48 and 72 hours since the initiation of the study product infusion.

Time frame:
72 hours
Reported as:
Median · pg/mL
Plasma Receptor for Advanced Glycation Endproducts (RAGE)
pg/mLHuman Mesenchymal Stromal CellsCell Reconstitution Media
6 Hour62 (-839 to 954)-137 (-1412 to 626)
24 Hour-1249 (-4152 to 598)100 (-1712 to 2224)
48 Hour-1603 (-4710 to -338)-906 (-3945 to 806)
72 Hour-2619 (-8478 to -993)-2054 (-6275 to -198)
Statistical analysis
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Wilcoxon (Mann-Whitney) · p = 0.60
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Wilcoxon (Mann-Whitney) · p = 0.04
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Wilcoxon (Mann-Whitney) · p = 0.09
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Wilcoxon (Mann-Whitney) · p = 0.38
SecondaryPlasma Interleukin-6 (IL-6)

Change in levels of plasma interleukin-6 from baseline compared to 6, 24, 48 and 72 hours

Time frame:
72 hours
Reported as:
Median · pg/mL
Plasma Interleukin-6 (IL-6)
pg/mLHuman Mesenchymal Stromal CellsCell Reconstitution Media
6 Hour-10.1 (-53.0 to 6.9)-3.3 (-16.5 to 4.3)
24 Hour-9.1 (-60.9 to 19.2)5.2 (-12.4 to 82.7)
48 Hour-10.7 (-66.2 to 31.6)4.1 (-16.3 to 64.5)
72 Hour-11.7 (-90.3 to 56.6)2.8 (-56.0 to 35.5)
Statistical analysis
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Wilcoxon (Mann-Whitney) · p = 0.28
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Wilcoxon (Mann-Whitney) · p = 0.10
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Wilcoxon (Mann-Whitney) · p = 0.15
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Wilcoxon (Mann-Whitney) · p = 0.34
SecondaryPlasma Interleukin-8 (IL-8)

Change in levels of plasma interleukin-8 from baseline at 6, 24, 48 and 72 hours since the initiation of study product infusion.

Time frame:
72 hours
Reported as:
Median · pg/mL
Plasma Interleukin-8 (IL-8)
pg/mLHuman Mesenchymal Stromal CellsCell Reconstitution Media
6 Hour-1.0 (-5.5 to 5.4)-0.4 (-4.2 to 3.4)
24 Hour-0.3 (-9.0 to 6.8)0.3 (-4.9 to 7.3)
48 Hour-2.5 (-4.9 to 4.7)-0.7 (-5.9 to 3.7)
72 Hour0.4 (-4.1 to 4.9)1.4 (-6.9 to 11.2)
Statistical analysis
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Wilcoxon (Mann-Whitney) · p = 0.85
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Wilcoxon (Mann-Whitney) · p = 0.50
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Wilcoxon (Mann-Whitney) · p = 0.64
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Wilcoxon (Mann-Whitney) · p = 0.70
SecondaryPlasma Tumor Necrosis Factor Receptor 1 (TNFR-1)

Change in levels of plasma TNFR-1 from baseline at 6, 24, 48 and 72 hours since the initiation of study product infusion.

Time frame:
72 hours
Reported as:
Median · pg/mL
Plasma Tumor Necrosis Factor Receptor 1 (TNFR-1)
pg/mLHuman Mesenchymal Stromal CellsCell Reconstitution Media
6 Hour-1 (-679 to 734)271 (-345 to 1629)
24 Hour231 (-422 to 2009)1047 (294 to 2730)
48 Hour721 (-517 to 1756)1596 (354 to 5821)
72 Hour382 (-40 to 1438)985 (-137 to 2999)
Statistical analysis
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Wilcoxon (Mann-Whitney) · p = 0.32
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Wilcoxon (Mann-Whitney) · p = 0.02
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Wilcoxon (Mann-Whitney) · p = 0.02
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Wilcoxon (Mann-Whitney) · p = 0.19
SecondaryPlasma Protein C

Change in levels of plasma protein C from baseline at 6, 24, 48 and 72 hours since the initiation of study product infusion.

Time frame:
72 hours
Reported as:
Median · pg/mL
Plasma Protein C
pg/mLHuman Mesenchymal Stromal CellsCell Reconstitution Media
6 Hour7.3 (-26.1 to 38.7)-2.9 (-17.0 to 15.0)
24 Hour8.5 (-8.2 to 27.5)6.8 (-27.6 to 30.3)
48 Hour14.0 (-14.2 to 47.2)12.7 (-19.7 to 38.2)
72 Hour26.7 (-15.3 to 55.6)8.3 (-25.3 to 49.1)
Statistical analysis
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Wilcoxon (Mann-Whitney) · p = 0.16
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Wilcoxon (Mann-Whitney) · p = 0.64
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Wilcoxon (Mann-Whitney) · p = 0.80
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Wilcoxon (Mann-Whitney) · p = 0.40
SecondaryPlasma Angiopoietin-1 (ANG-1)

Change in levels of plasma angiopoietin-1 from the baseline to 6, 24, 48 and 72 hours since the initiation of study product infusion.

Time frame:
72 hours
Reported as:
Median · pg/mL
Plasma Angiopoietin-1 (ANG-1)
pg/mLHuman Mesenchymal Stromal CellsCell Reconstitution Media
6 Hour-224 (-1548 to 1799)-292 (-1366 to 1915)
24 Hour786 (-8 to 3645)582 (-1350 to 1827)
48 Hour612 (-2033 to 3005)661 (-881 to 3977)
72 Hour148 (-2462 to 3950)59 (-1646 to 2557)
Statistical analysis
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Wilcoxon (Mann-Whitney) · p = 0.85
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Wilcoxon (Mann-Whitney) · p = 0.22
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Wilcoxon (Mann-Whitney) · p = 0.61
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Wilcoxon (Mann-Whitney) · p = 0.98
SecondaryPlasma Lipoxin A4

Change in levels of plasma lipoxin A4 from baseline compared to 6, 24, 48 and 72 hours

Time frame:
72 hours

No measurements were reported for this outcome.

SecondaryPlasma Resolvin D1

Change in levels of plasma Resolvin D1 from baseline compared to 6, 24, 48 and 72 hours

Time frame:
72 hours

No measurements were reported for this outcome.

SecondaryPlasma Keratinocyte Growth Factor (KGF)

Change in levels of plasma KGF from baseline at 6, 24, 48 and 72 hours since the initiation of study product infusion.

Time frame:
72 hours

No measurements were reported for this outcome.

SecondaryUrine Microalbumin

Change in levels of urine microalbumin from baseline compared to 24 and 48 hours

Time frame:
48 hours

No measurements were reported for this outcome.

SecondaryTotal Protein in Min-bronchoalveolar Lavage (mBAL)

Change in total protein levels in from baseline to day 2

Time frame:
2 days

No measurements were reported for this outcome.

SecondaryTolerability of the hMSCs - Incidence of Pre-specified Infusion-associated Events and Unexpected Severe Adverse Events

Tolerability of the hMSCs, defined as the incidence of pre-specified infusion-associated events and unexpected severe adverse events in ARDS patients treated with human MSCs

Time frame:
24 hours
Reported as:
Count of participants · Participants
Tolerability of the hMSCs - Incidence of Pre-specified Infusion-associated Events and Unexpected Severe Adverse Events
ParticipantsHuman Mesenchymal Stromal CellsCell Reconstitution Media
Tolerability of the hMSCs - Incidence of Pre-specified Infusion-associated Events and Unexpected Severe Adverse Events22
Statistical analysis
  • Human Mesenchymal Stromal Cells vs Cell Reconstitution Media · Fisher Exact · p = >0.99

Adverse events

Collected over Adverse event data was collected through 28 days from study product infusion. Death data was collected up to 6 months.. Non-serious events are listed at a 0% frequency threshold.

Adverse event summary by group
GroupDeathsSeriousOther
Human Mesenchymal Stromal Cells24/59 (40.7%)3/59 (5.1%)9/59 (15.3%)
Cell Reconstitution Media21/61 (34.4%)2/61 (3.3%)6/61 (9.8%)
Most frequent serious events
Most frequent serious events
EventHuman Mesenchymal Stromal CellsCell Reconstitution Media
ECMOCardiac disorders1/590/61
Tension pneumothoraxRespiratory, thoracic and mediastinal disorders1/590/61
PEA arrestCardiac disorders1/590/61
Asymmetric perfusionBlood and lymphatic system disorders0/591/61
Partial hemorrhageNervous system disorders0/591/61
Most frequent other events
Showing 10 of 11
Most frequent other events
EventHuman Mesenchymal Stromal CellsCell Reconstitution Media
Deep Vein ThrombosisNervous system disorders3/592/61
VAP SepsisBlood and lymphatic system disorders2/591/61
SepsisBlood and lymphatic system disorders1/590/61
Decrease in oxygen saturationRespiratory, thoracic and mediastinal disorders1/590/61
AgitationRespiratory, thoracic and mediastinal disorders1/590/61
C, diff infectionGastrointestinal disorders1/590/61
DiplopiaNervous system disorders1/590/61
Pulmonary embolismRespiratory, thoracic and mediastinal disorders0/591/61
Aspiration pneumoniaRespiratory, thoracic and mediastinal disorders0/591/61
ArrhythmiaCardiac disorders0/591/61

Baseline characteristics

Age, Continuous
Age, Continuous(years)Human Mesenchymal Stromal CellsCell Reconstitution MediaTotal
Mean54.0 ± 14.457.0 ± 15.155.5 ± 14.8
Sex: Female, Male
Sex: Female, Male(Participants)Human Mesenchymal Stromal CellsCell Reconstitution MediaTotal
Female202949
Male393271
Ethnicity (NIH/OMB)
Ethnicity (NIH/OMB)(Participants)Human Mesenchymal Stromal CellsCell Reconstitution MediaTotal
Hispanic or Latino212647
Not Hispanic or Latino303161
Unknown or Not Reported8412
Race (NIH/OMB)
Race (NIH/OMB)(Participants)Human Mesenchymal Stromal CellsCell Reconstitution MediaTotal
American Indian or Alaska Native101
Asian9514
Native Hawaiian or Other Pacific Islander000
Black or African American628
White223254
More than one race000
Unknown or Not Reported212243
Region of Enrollment
Region of Enrollment(participants)Human Mesenchymal Stromal CellsCell Reconstitution MediaTotal
United States5961120
COVID positive
COVID positive(Participants)Human Mesenchymal Stromal CellsCell Reconstitution MediaTotal
Yes5645101
No31619
Primary Cause of ARDS
Primary Cause of ARDS(Participants)Human Mesenchymal Stromal CellsCell Reconstitution MediaTotal
COVID-19 Pneumonia5644100
Non COVID-19 Pneumonia055
Sepsis134
Trauma257
Aspiration033
Other011
Acute Physiology, Age, Chronic Health Evaluation (APACHE) III
Acute Physiology, Age, Chronic Health Evaluation (APACHE) III(units on a scale)Human Mesenchymal Stromal CellsCell Reconstitution MediaTotal
Mean100.8 ± 26.093.6 ± 26.097.1 ± 26.1

12 further baseline measures are reported on the registry.

08

Study locations

7 sites
  • University of California Davis Medical Center
    Sacramento, California 95817, United States
  • Zuckerberg San Francisco General Hospital and Trauma Center
    San Francisco, California 94110, United States
  • University of California San Francisco
    San Francisco, California 94143, United States
  • Oregon Health & Science University
    Portland, Oregon 97239, United States
  • Vanderbilt University Medical Center
    Nashville, Tennessee 37232, United States
  • Memorial Hermann Hospital - Texas Medical Center
    Houston, Texas 77030, United States
  • Harborview Medical Center
    Seattle, Washington 98112, United States
09

References and documents

Publications

  • Matthay MA, Zhuo H, Sarma A, Alipanah-Lechner N, Hendrickson C, Kornblith LZ, Schreiber M, Zonies D, Khan A, Robinson B, Johnson NJ, Ware LB, Guillamondegui O, Casey J, Moore L, Patel B, Kao L, Wade CE, Fox E, Cox C, Khawanja F, Aguillon Prada R, Hossri S, Callcut R, Albertson T, Delucchi KL, McMillan M, Langelier CR, Pati S, McKenna DH, Leroux C, Calfee CS, Liu KD. Treatment with Allogeneic Mesenchymal Stromal Cells for Moderate to Severe Acute Respiratory Distress Syndrome: A Double-Blind, Placebo-controlled, Multicenter Phase 2b Clinical Trial (STAT). Am J Respir Crit Care Med. 2026 Feb 1;212(3):428-439. doi: 10.1164/rccm.202411-2254OC. PubMed 40728562 ↗

Study documents

  • Study protocol · Apr 19, 2022
  • Statistical analysis plan · Apr 28, 2022
  • Informed consent form · Feb 24, 2022

Documents are hosted by the registry — open the source record to download them.

Individual participant data

Plan to share: No — We do not have plan to share IPD data to other researchers.

10

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Dec 4, 2025, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
11

Registry details

Key details

Study ID
NCT03818854
Lead sponsor
Michael A. Matthay
Collaborators
United States Department of Defense, Harborview Injury Prevention and Research Center, Oregon Health and Science University, Vanderbilt University Medical Center, The University of Texas Health Science Center, Houston, University of Minnesota
Responsible party
Michael A. Matthay (Professor, University of California, San Francisco) — Sponsor-investigator
First posted
Jan 28, 2019
Start date
Nov 26, 2019
Primary completion
Mar 30, 2024
Completion
Jun 30, 2024
Results posted
Dec 4, 2025
Last update
Dec 4, 2025

Study contacts

Michael Matthay, MD
principal investigator · University of California, San Francisco

Oversight

Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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