ABSTRACT
RATIONALE: There are limited therapeutic options for patients with COVID-19-related acute respiratory distress syndrome (ARDS) with inflammation-mediated lung injury. Mesenchymal stromal cells offer promise as immunomodulatory agents. OBJECTIVES: Evaluation of efficacy and safety of allogeneic mesenchymal cells in mechanically-ventilated patients with moderate or severe COVID-induced respiratory failure. METHODS: Patients were randomized to two infusions of 2 million cells/kg or sham infusions, in addition to standard of care. We hypothesized that cell therapy would be superior to sham-control for the primary endpoint of 30-day mortality. The key secondary endpoint was ventilator-free survival within 60 days, accounting for deaths and withdrawals in a ranked analysis. MEASUREMENTS AND MAIN RESULTS: At the third interim analysis, the Data and Safety Monitoring Board recommended that the trial halt enrollment as the pre-specified mortality reduction from 40% to 23% was unlikely to be achieved (n=222 out of planned 300). Thirty-day mortality was 37.5% (42/112) in cell recipients versus 42.7% (47/110) in control patients (RR 0.88;95% CI 0.64,1.21;p=0.43). There were no significant differences in days alive off ventilation within 60 days (median rank 117.3 [IQR:60.0,169.5] in cell patients and 102.0 [IQR:54.0,162.5] in controls; higher is better). Resolution or improvement of ARDS at 30-days was observed in 51/104 (49.0%) cell recipients and 46/106 (43.4%) of control patients (OR 1.36;95% CI 0.57, 3.21). There were no infusion-related toxicities and overall serious adverse events over 30 days were similar. CONCLUSIONS: Mesenchymal cells, while safe, did not improve 30-day survival or 60-day ventilator-free days in patients with moderate/severe COVID-related acute respiratory distress syndrome. Clinical trial registration available at www. CLINICALTRIALS: gov, ID:NCT04371393. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/).
ABSTRACT
BACKGROUND AIMS: The acute respiratory distress syndrome (ARDS) resulting from coronavirus disease 2019 (COVID-19) is associated with a massive release of inflammatory cytokines and high mortality. Mesenchymal stromal cells (MSCs) have anti-inflammatory properties and have shown activity in treating acute lung injury. Here the authors report a case series of 11 patients with COVID-19-associated ARDS (CARDS) requiring mechanical ventilation who were treated with remestemcel-L, an allogeneic MSC product, under individual patient emergency investigational new drug applications. METHODS: Patients were eligible if they were mechanically ventilated for less than 72 h prior to the first infusion. Patients with pre-existing lung disease requiring supplemental oxygen or severe liver or kidney injury were excluded. Each patient received two infusions of remestemcel-L at a dose of 2 million cells/kg per infusion given 48-120 h apart. RESULTS: Remestemcel-L infusions were well tolerated in all 11 patients. At the end of the 28-day follow-up period, 10 (91%, 95% confidence interval [CI], 59-100%) patients were extubated, nine (82%, 95% CI, 48-97%) patients remained liberated from mechanical ventilation and were discharged from the intensive care unit and two (18%, 95 CI%, 2-52%) patients died. The median time to extubation was 10 days. Eight (73%, 95% CI, 34-100%) patients were discharged from the hospital. C-reactive protein levels significantly declined within 5 days of MSC infusion. CONCLUSIONS: The authors demonstrate in this case series that remestemcel-L infusions to treat moderate to severe CARDS were safe and well tolerated and resulted in improved clinical outcomes.