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CompletedNCT04865107CIRCA-19 RCTUpdated Jul 31, 2025

Cellular Immuno-Therapy for COVID-19 ARDS Randomized Clinical Trial

A Phase 2 interventional study of UC-MSCs and Placebo in Covid19 and Acute Respiratory Distress Syndrome, sponsored by Ottawa Hospital Research Institute. Completed at 4 sites in Canada. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2025-07-31.

Sponsored by Ottawa Hospital Research Institute · Phase 2, Interventional, and Treatment

Phase
Phase 2
Study type
Interventional
Enrollment
22
Allocation
Randomized
Ages
18 Years and older
Sex
All
01

Study summary

This is a Phase 2 multicenter randomized (2:1), placebo-controlled trial to evaluate early signs of efficacy of allogeneic, umbilical cord-derived (UC) mesenchymal stromal cells (MSCs) in patients with COVID-19 and Acute Respiratory Distress Syndrome (ARDS).

Randomized participants (N=54) will receive 3 daily doses of up to 90-million cells/unit dose (cumulative dose of up to 270 million UC-MSCs) or blinded placebo. The MSC product will be provided as 2.5 million cells/ml suspended in PlasmaLyte A containing 5% Human Albumin. The appearance-matched placebo product contains the same excipients, PlasmaLyte A and 5% Human Albumin, as the UC-MSCs.

02

Conditions studied

  • Covid19
  • Acute Respiratory Distress Syndrome
03

In context

COVID-19

7,638 studies on the registry are indexed under COVID-19; 488 are open to participants now.

This study's enrollment of 22 is below the median of 100 across 4,098 interventional studies indexed under COVID-19.

Browse COVID-19 studies →

Lead sponsor

Ottawa Hospital Research Institute is the lead sponsor of 538 studies on the registry; 100 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

  • Age of ≥18 years
  • Laboratory-confirmed SARS-CoV-2 infection during the current admission
  • On invasive, non-invasive mechanical ventilation (NIV) (PEEP ≥5 cmH20) or high-flow nasal canula (HFNC) oxygen therapy (minimum total flow rate of 40 lpm)
  • ARDS (onset \<96h) as per the international consensus definition (P/F ratio \< 300 with PEEP ≥5cm H20 or on HFNC), not due primarily to cardiac causes.

Exclusion criteria

Exclusion Criteria:

  • No consent/inability to obtain consent
  • Rockwood Clinical Frailty Score > 4
  • Moribund patient not expected to survive 24 hours
  • Any other irreversible disease or condition for which 6-month mortality is estimated to be greater than 50%
  • Currently receiving extracorporeal life support
  • Pregnant or lactating
  • Patients with a prior or concurrent malignancy whose natural history or treatment does not have the potential to interfere with the safety or efficacy assessment of the investigational regimen are eligible for this trial
  • Moderate to severe chronic liver disease (Childs-Pugh Score > 12)
  • Severe chronic respiratory disease with a baseline PaCO2 > 50 mm Hg or the use of home oxygen
  • Documented deep venous thrombosis or pulmonary embolism within the preceding 3 months
  • Inability/contra-indications to receiving local standard of care thromboprophylaxis
  • Chronic immunosuppression (any chronic immunotherapy including daily oral steroid use >6months)
  • Known HIV, Hep B/C positive, or active tuberculosis
  • Multisystem shock (SOFA score change from baseline of >2 in >2 systems)
  • Patient, surrogate, or physician not committed to full support including intubation (exception: a patient will not be excluded if he/she would receive all supportive care except for attempts at resuscitation from cardiac arrest)
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Study design

Phase
Phase 2
Primary purpose
Treatment
Allocation
Randomized
Intervention model
Parallel assignment
Masking
Quadruple (Participant, Care provider, Investigator, Outcomes assessor)
Enrollment
22 participants (actual)

Study arms

  • Experimental
    MSCs Arm

    3 daily doses of up to 90-million cells/unit dose (cumulative dose of up to 270 million UC-MSCs)

    Biological: UC-MSCs

  • Placebo comparator
    Placebo Arm

    3 daily doses of up to 90-million cells/unit dose (cumulative dose of up to 270 million UC-MSCs)

    Biological: Placebo

Interventions

  • BiologicalUC-MSCs

    3 daily doses of up to 90-million cells/unit dose (cumulative dose of up to 270 million UC-MSCs)

  • BiologicalPlacebo

    PlasmaLyte A and 5% Human Albumin

06

What researchers measure

Primary outcomes

  1. Number of days free of oxygen by NIV/HFNC or mechanical ventilation at Day 28

    Time frame: Day 28

Secondary outcomes

  1. Biomarkers of systemic inflammatory response

    Interleukin levels change from Baseline to 24 hours after each MSC infusion

    Time frame: Change from Baseline to 24 hours after each MSC infusion

  2. Biomarkers of endothelial function

    Angiopoietin levels change from Baseline to 24 hours after each MSC infusion

    Time frame: Change from Baseline to 24 hours after each MSC infusion

  3. ICU mortality

    Number of deaths at day 28

    Time frame: Day 28

Other outcomes

  1. Safety events (SAEs, AEs)

    allergic reactions, infusion related reactions, and venous and arterial thrombotic events

    Time frame: At time of infusion until one year post-infusion

07

Study locations

4 sites
  • Lakeridge Health
    Oshawa, Ontario ON L1G 2B9, Canada
  • The Ottawa Hospital
    Ottawa, Ontario K1H 8L6, Canada
  • St. Michael's Hospital
    Toronto, Ontario M5B 1W8, Canada
  • Centre Hospitalier de l'Université de Montréal
    Montreal, Quebec H2X 3E4, Canada
08

References and documents

Individual participant data

Plan to share: No

No publications or documents are linked to this record.

09

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Jul 31, 2025, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT04865107
Lead sponsor
Ottawa Hospital Research Institute
Collaborators
Canadian Institutes of Health Research (CIHR)
Responsible party
Sponsor
First posted
Apr 29, 2021
Start date
Apr 27, 2021
Primary completion
Apr 1, 2022
Completion
Apr 1, 2022
Last update
Jul 31, 2025

Study contacts

Duncan J Stewart, MD
principal investigator · The Ottawa Hospital

Oversight

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

Not currently enrolling

This study is completed, as verified in Jul 2025. You cannot join it, but the record below documents what was studied.

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