Safety and efficacy study of allogeneic human menstrual blood stromal cells secretome to treat severe COVID-19 patients: clinical trial phase I & II

Abstract

Background: Cell-free Mesenchymal stromal cells (MSCs) have been considered due to their capacity to modulate the immune system and suppress cytokine storms caused by SARS-CoV-2. This prospective randomized double-blind placebo-controlled clinical trial aimed to assess the safety and efficacy of secretome derived from allogeneic menstrual blood stromal cells (MenSCs) as a treatment in patients with severe COVID-19.

Methods: Patients with severe COVID-19 were randomized (1:1) to either MenSC-derived secretome treatment or the control group. Subjects received five intravenous infusions of 5 mL secretome or the same volume of placebo for five days and were monitored for safety and efficacy for 28 days after treatment. Adverse events, laboratory parameters, duration of hospitalization, clinical symptom improvement, dynamic of O₂ saturation, lymphocyte number, and serial chest imaging were analyzed.

Results: All safety endpoints were observed without adverse events after 72 h of secretome injection. Within 28 days after enrollment, 7 patients (50%) were intubated in the treated group versus 12 patients (80%) in the control group. Overall, 64% of patients had improved oxygen levels within 5 days of starting treatment (P < 0.0001) and there was a survival rate of 57% in the treatment group compared to 28% in the control group was (P < 0.0001). Laboratory values revealed that significant acute phase reactants declined, with mean C-reactive protein, ferritin, and D-dimer reduction of 77% (P < 0.001), 43% (P < 0.001), and 42% (P < 0.05), respectively. Significant improvement in lymphopenia was associated with an increase in mean CD4⁺ and CD8⁺ lymphocyte counts of 20% (P = 0.06) and 15% (P < 0.05), respectively. Following treatment, percentage of pulmonary involvement showed a significant improvement in the secretome group (P < 0.0001). This improvement differed significantly between survivors and those who were dying (P < 0.005).

Conclusions: For the first time, this study demonstrated that in hospitalized patients with severe COVID-19, therapy with MenSCs-derived secretome leads to reversal of hypoxia, immune reconstitution, and downregulation of cytokine storm, with no adverse effects attributable to the treatment. Given these outcomes, it may be possible to use this type of treatment for serious inflammatory lung disease with a mechanism similar to COVID-19 in the future. However, it is necessary to evaluate the safety and efficacy of MenSCs-derived secretome therapy in clinical trials on a larger population of patients.

Trial registration: ClinicalTrials.gov Identifier: NCT05019287. Registered 24AGUEST 2021, retrospectively registered, https://clinicaltrials.gov/ct2/show/record/NCT05019287 . IRCT, IRCT20180619040147N6. Registered 04/01/2021.

Keywords: COVID-19; GMP; Menstrual blood stromal cells; New treatment; Secretome.

Fig. 1

Flow diagram showing enrollment, allocation, follow up and analysis of patients

Fig. 2

Kaplan–Meier survival curves for overall survival in control and treated groups which showed that the difference in survival rate between these two groups was statistically significant (P < 0.001)

Fig. 3

Change in acute phase reactant (CRP) levels before and after of secretome administration. Mean reduction of CRP in treated group was 77% (P < 0.001)

Fig. 4

Decreasing trend of LDH level in the treated group within 10 days of starting treatment. A significant decrease in LDH levels was observed 10 days post-treatment (P < 0.001)

Fig. 5

Decreasing trend of D.Dimer level in the treated group within 5 days of starting treatment. Mean reduction of D-dimer in treated group was 42% (P < 0.05)

Fig. 6

Decreased trend of ferritin level in the treated group within 5 days of starting treatment. Mean reduction of ferritin in treated group was 43% (P < 0.001)

Fig. 7

Flow cytometry gating strategy for CD4⁺ and CD8⁺ cells. Lymphocytes were first identified by R1 gate in forward scatter (FSC) and side scatter (SSC) graph. CD4⁺ and CD8⁺ T cells were then measured by means of anti CD4 and anti CD8 antibodies, labeled by FITC and PE respectively; as illustrated in the histogram graphs separately. A and B represent the changes in CD4⁺ and CD8⁺ lymphocyte counts between 5 and 10 days after secretome administration in a 35-year-old male patient, respectively

Fig. 8

Change in the CT scan percentage of lung involvement before and after of secretome administration. This treatment significantly improved the lung involvement of patients when they were discharged from hospital. Furthermore, this effect was completely different in both groups of surviving and dying patients

Fig. 9

Lung CT scan. A Significant improvement in lung lesions within 10 days of starting treatment in a 37-year-old male patient B Significant improvement in lung lesions within 5 days of starting treatment in a 45-year-old female patient