Repair of Acute Respiratory Distress Syndrome in COVID-19 by Stromal Cells (REALIST-COVID Trial): A Multicenter, Randomized, Controlled Clinical Trial

Long-term outcomes of mesenchymal stem cell therapy in severe COVID-19 patients: 3-year follow-up of a randomized, double-blind, placebo-controlled trial

BACKGROUND

The long-term effects and outcomes of human mesenchymal stem cell (MSC) therapy in patients with severe coronavirus disease 2019 (COVID-19) remain poorly understood. This study aimed to evaluate the extended safety and efficacy of MSC treatment in severe patients with COVID-19 who participated in our earlier randomized, double-blind, placebo-controlled clinical trial, with follow-up conducted over 3 years.

METHODS

One hundred patients with severe COVID-19 were randomized to receive either an MSC infusion (n = 65, 4 × 107 cells/dose, on days 0, 3, and 6) or a placebo, with both groups receiving the standard of care. At 36 months post-MSC therapy, patients were followed up to long-term safety and efficacy, particularly the effects of MSC therapy on persistent COVID-19 symptoms. Evaluated outcomes included lung imaging results, 6-min walking distance (6-MWD), pulmonary function test results, quality of life scores based on the Short Form-36 (SF-36) health survey, Long COVID symptoms, new-onset comorbidities, tumor marker levels, and rates of COVID-19 reinfection.

RESULTS

Three years post-treatment, 46.94% (23/49) of patients in the MSC group and 34.48% (10/29) in the placebo group showed normal findings on computed tomography (CT) images (odds ratio [OR] = 1.68, 95% confidence interval [CI]: 0.65-4.34). The general health (GH) score from the SF-36 was higher in the MSC group (67.0) compared to the placebo group (50.0), with a difference of 12.86 (95% CI: 1.44-24.28). Both groups showed similar results for total lung severity scores (TSS), 6-MWD, pulmonary function tests, and Long COVID symptoms. No significant differences between groups were observed in new-onset complications (including tumorigenesis) or tumor marker levels. After adjusting for China's dynamic zero-COVID-19 strategy, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reinfection rates were 53.06% (26/49) in the MSC group and 67.86% (19/28) in the placebo group (OR = 0.54, 95% CI: 0.20-1.41).

CONCLUSIONS

These findings support the long-term safety of MSC therapy in patients with severe COVID-19 over 3 years. MSC treatment may offer potential benefits for lung recovery and improved quality of life in patients experiencing Long COVID symptoms.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT04288102. Registered 28 February 2020, https://clinicaltrials.gov/study/NCT04288102 .

An update on the pharmacological management of acute respiratory distress syndrome

INTRODUCTION

Acute respiratory distress syndrome (ARDS) is characterized by acute inflammatory injury to the lungs, alterations in vascular permeability, loss of aerated tissue, bilateral infiltrates, and refractory hypoxemia. ARDS is considered a heterogeneous syndrome, which complicates the search for effective therapies. The goal of this review is to provide an update on the pharmacological management of ARDS.

AREAS COVERED

The difficulties in finding effective pharmacological therapies are mainly due to the challenges in designing clinical trials for this unique, varied population of critically ill patients. Recently, some trials have been retrospectively analyzed by dividing patients into hyper-inflammatory and hypo-inflammatory sub-phenotypes. This approach has led to significant outcome improvements with some pharmacological treatments that previously failed to demonstrate efficacy, which suggests that a more precise selection of ARDS patients for clinical trials could be the key to identifying effective pharmacotherapies. This review is provided after searching the main studies on this topics on the PubMed and clinicaltrials.gov databases.

EXPERT OPINION

The future of ARDS therapy lies in precision medicine, innovative approaches to drug delivery, immunomodulation, cell-based therapies, and robust clinical trial designs. These should lead to more effective and personalized treatments for patients with ARDS.

Mesenchymal Stem Cells on Mortality in COVID-19 Patients: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

The Coronavirus disease-2019 (COVID-19) pandemic continues, and the death toll continues to surge. This meta-analysis aimed to determine the efficacy of mesenchymal stem cells (MSCs) on mortality in patients with COVID-19.

METHODS

A systematic search was made of PubMed, Embase, Cochrane Library, and clinicaltrials.gov, without language restrictions. Randomized controlled trials (RCTs) on treatment of COVID-19 with MSCs, compared with placebo or blank, were reviewed. Studies were pooled to risk ratios (RRs), with 95% confidence intervals (CIs).

RESULTS

Seventeen RCTs (enrolling 1019 participants) met the inclusion criteria. MSCs showed significant effect on 28-day mortality (RR 0.76, 95% CI 0.62 to 0.93; P = 0.008). There was no statistically significant difference in 60-day mortality (RR 0.87, 95% CI 0.70 to 1.09; P = 0.22), and 90-day mortality (RR 0.91, 95% CI 0.72 to 1.15; P = 0.44) between the two groups.

CONCLUSIONS

MSCs significantly reduced 28-day mortality in patients with COVID-19. The long-term effect of MSCs on mortality require further study.

Mesenchymal stem cells and their derived exosomes for the treatment of COVID-19

Coronavirus disease 2019 (COVID-19) is an acute respiratory infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). SARS-CoV-2 infection typically presents with fever and respiratory symptoms, which can progress to severe respiratory distress syndrome and multiple organ failure. In severe cases, these complications may even lead to death. One of the causes of COVID-19 deaths is the cytokine storm caused by an overactive immune response. Therefore, suppressing the overactive immune response may be an effective strategy for treating COVID-19. Mesenchymal stem cells (MSCs) and their derived exosomes (MSCs-Exo) have potent homing abilities, immunomodulatory functions, regenerative repair, and antifibrotic effects, promising an effective tool in treating COVID-19. In this paper, we review the main mechanisms and potential roles of MSCs and MSCs-Exo in treating COVID-19. We also summarize relevant recent clinical trials, including the source of cells, the dosage and the efficacy, and the clinical value and problems in this field, providing more theoretical references for the clinical use of MSCs and MSCs-Exo in the treatment of COVID-19.

Cell-based Therapies for Acute Respiratory Distress Syndrome: Where Are We Now?

There is considerable interest in the potential for cell-based therapies, particularly mesenchymal stromal cells (MSCs) and their products, as a therapy for acute respiratory distress syndrome (ARDS). MSCs exert effects via diverse mechanisms including reducing excessive inflammation by modulating neutrophil, macrophage and T-cell function, decreasing pulmonary permeability and lung edema, and promoting tissue repair. Clinical studies indicate that MSCs are safe and well tolerated, with promising therapeutic benefits in specific clinical settings, leading to regulatory approvals of MSCs for specific indications in some countries.This perspective reassesses the therapeutic potential of MSC-based therapies for ARDS given insights from recent cell therapy trials in both COVID-19 and in 'classic' ARDS, and discusses studies in graft-vs.-host disease, one of the few licensed indications for MSC therapies. We identify important unknowns in the current literature, address challenges to clinical translation, and propose an approach to facilitate assessment of the therapeutic promise of MSC-based therapies for ARDS.

Vascular leak in sepsis: physiological basis and potential therapeutic advances

Sepsis is a life-threatening condition characterised by endothelial barrier dysfunction and impairment of normal microcirculatory function, resulting in a state of hypoperfusion and tissue oedema. No specific pharmacological therapies are currently used to attenuate microvascular injury. Given the prominent role of endothelial breakdown and microcirculatory dysfunction in sepsis, there is a need for effective strategies to protect the endothelium. In this review we will discuss key mechanisms and putative therapeutic agents relevant to endothelial barrier function.

Investigational pharmacological agents for the treatment of ARDS

INTRODUCTION

Acute Respiratory Distress Syndrome (ARDS) is a heterogeneous form of lung injury with severe hypoxemia and bilateral infiltrates after an inciting event that results in diffuse lung inflammation with a high mortality rate. While research in COVID-related ARDS has resulted in several pharmacotherapeutic agents that have undergone successful investigation, non-COVID ARDS studies have not resulted in many widely accepted pharmacotherapeutic agents despite exhaustive research.

AREAS COVERED

The aim of this review is to discuss adjuvant pharmacotherapies targeting non-COVID Acute Lung Injury (ALI)/ARDS and novel therapeutics in COVID associated ALI/ARDS. In ARDS, variable data may support selective use of neuromuscular blocking agents, corticosteroids and neutrophil elastase inhibitors, but are not yet universally used. COVID-ALI/ARDS has data supporting the use of IL-6 monoclonal antibodies, corticosteroids, and JAK inhibitor therapy.

EXPERT OPINION

Although ALI/ARDS modifying pharmacological agents have been identified in COVID-related disease, the data in non-COVID ALI/ARDS has been less compelling. The increased use of more specific molecular phenotyping based on physiologic parameters and biomarkers, will ensure equipoise between groups, and will likely allow more precision in confirming pharmacological agent efficacy in future studies.

Signaling pathways and potential therapeutic targets in acute respiratory distress syndrome (ARDS)

Acute respiratory distress syndrome (ARDS) is a common condition associated with critically ill patients, characterized by bilateral chest radiographical opacities with refractory hypoxemia due to noncardiogenic pulmonary edema. Despite significant advances, the mortality of ARDS remains unacceptably high, and there are still no effective targeted pharmacotherapeutic agents. With the outbreak of coronavirus disease 19 worldwide, the mortality of ARDS has increased correspondingly. Comprehending the pathophysiology and the underlying molecular mechanisms of ARDS may thus be essential to developing effective therapeutic strategies and reducing mortality. To facilitate further understanding of its pathogenesis and exploring novel therapeutics, this review provides comprehensive information of ARDS from pathophysiology to molecular mechanisms and presents targeted therapeutics. We first describe the pathogenesis and pathophysiology of ARDS that involve dysregulated inflammation, alveolar-capillary barrier dysfunction, impaired alveolar fluid clearance and oxidative stress. Next, we summarize the molecular mechanisms and signaling pathways related to the above four aspects of ARDS pathophysiology, along with the latest research progress. Finally, we discuss the emerging therapeutic strategies that show exciting promise in ARDS, including several pharmacologic therapies, microRNA-based therapies and mesenchymal stromal cell therapies, highlighting the pathophysiological basis and the influences on signal transduction pathways for their use.

Umbilical cord blood and cord tissue banking as somatic stem cell resources to support medical cell modalities

Human umbilical cord blood (CB) and umbilical cord tissue (UC) are attractive sources of somatic stem cells for gene and cell therapies. CB and UC can be obtained noninvasively from donors. CB, a known source of hematopoietic stem cells for transplantation, has attracted attention as a new source of immune cells, including universal chimeric antigen receptor-T cell therapy (CAR-T) and, more recently, universal CAR-natural killer cells. UC-derived mesenchymal stromal cells (UC-MSCs) have a higher proliferation potency than those derived from adult tissues and can be used anon-HLA restrictively. UC-MSCs meet the MSC criteria outlined by the International Society of Gene and Cellular Therapy. UC-MSCs are negative for HLA-DR, CD80, and CD86 and have an immunosuppressive ability that mitigates the proliferation of activated lymphocytes through secreting indoleamine 2,3-dioxygenase 1 and prostaglandin E2, and the expression of PD-L2 and PD-L1. We established the off-the-shelf cord blood/cord bank IMSUT CORD to support novel cell therapy modalities, including the CB-derived immune cells, MSCs, MSCs-derived extracellular vesicles, biological carriers loaded with chemotherapy drugs, prodrug, oncolytic viruses, nanoparticles, human artificial chromosome, combinational products with a scaffold, bio3D printing, and so on.

Efficacy of Wharton Jelly Mesenchymal Stromal Cells infusions in moderate to severe SARS-Cov-2 related acute respiratory distress syndrome: a phase 2a double-blind randomized controlled trial

Background

The COVID-19 pandemic caused a wave of acute respiratory distress syndrome (ARDS) with a high in-hospital mortality, especially in patients requiring invasive mechanical ventilation. Wharton Jelly-derived Mesenchymal Stromal Cells (WJ-MSCs) may counteract the pulmonary damage induced by the SARS-CoV-2 infection through pro-angiogenic effects, lung epithelial cell protection, and immunomodulation.

Methods

In this randomized, double-blind, placebo-controlled phase 2a trial, adult patients receiving invasive mechanical ventilation for SARS-CoV-2 induced moderate or severe ARDS were assigned to receive 1 intravenous infusion of 1 × 106 WJ-MSCs/kg or placebo within 48 h of invasive ventilation followed by 2 infusions of 0.5 × 106 WJ-MSCs/kg or placebo over 5 days. The primary endpoint was the percentage of patients with a PaO2/FiO2 > 200 on day 10.

Results

Thirty patients were included from November 2020 to May 2021, 15 in the WJ-MSC group and 15 in the placebo group. We did not find any significant difference in the PaO2/FiO2 ratio at day 10, with 18 and 15% of WJ-MSCs and placebo-treated patients reaching a ratio >200, respectively. Survival did not differ in the 2 groups with a 20% mortality rate at day 90. While we observed a higher number of ventilation-free days at 28 days in the WJ-MSC arm, this difference was not statistically significant (median of 11 (0-22) vs. 0 (0-18), p = 0.2). The infusions were well tolerated, with a low incidence of anti-HLA alloimmunization after 90 days.

Conclusion

While treatment with WJ-MSCs appeared safe and feasible in patients with SARS-CoV2 moderate or severe ARDS in this phase 2a trial, the treatment was not associated with an increased percentage of patients with P/F > 200 at 10d, nor did 90 day mortality improve in the treated group.

Clinical trial registration

https://beta.clinicaltrials.gov/study/NCT04625738, identifier NCT04625738.