Royal College of Surgeons in Ireland
The safety and potential efficacy of exosomes overexpressing CD24 (EXO-CD24) in mild-moderate COVID-19 related ARDS.pdf (1.64 MB)

The safety and potential efficacy of exosomes overexpressing CD24 (EXO-CD24) in mild-moderate COVID-19 related ARDS

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journal contribution
posted on 2024-04-30, 08:20 authored by Ioannis Grigoropoulos, Ronan MacLoughlinRonan MacLoughlin, Sotirios Tsiodras

Introduction: EXO-CD24 are exosomes genetically manipulated to over-express Cluster of Differentiation (CD) 24. It consists of two breakthrough technologies: CD24, the drug, as a novel immunomodulator that is smarter than steroids without any side effects, and exosomes as the ideal natural drug carrier.

Methods: A randomized, single blind, dose-finding phase IIb trial in hospitalized patients with mild to moderate Coronavirus disease 2019 (COVID-19) related Acute Respiratory Distress Syndrome (ARDS) was carried out in two medical centers in Athens. Patients received either 109 or 1010 exosome particles of EXO-CD24, daily, for five consecutive days and monitored for 28 days. Efficacy was assessed at day 7 among 91 patients who underwent randomization. The outcome was also compared in a post-hoc analysis with an income control group (n = 202) that fit the inclusion and exclusion criteria.

Results: The mean age was 49.4 (± 13.2) years and 74.4% were male. By day 7, 83.7% showed improved respiratory signs and 64% had better oxygen saturation (SpO2) (p < 0.05). There were significant reductions in all inflammatory markers, most notably in C-reactive protein (CRP), lactate dehydrogenase (LDH), ferritin, fibrinogen and an array of cytokines. Conversely, levels of the anti-inflammatory cytokine Interleukin-10 (IL-10) were increased (p < 0.05). Of all the documented adverse events, none were considered treatment related. No drug-drug interactions were noted. Two patients succumbed to COVID-19. Post-hoc analysis revealed that EXO-CD24 patients exhibited greater improvements in clinical and laboratory outcomes compared to an observational income control group.

Conclusions: EXO-CD24 presents a promising therapeutic approach for hyper-inflammatory state and in particular ARDS. Its unique combination of exosomes, as a drug carrier, and CD24, as an immunomodulator, coupled with inhalation administration, warrants further investigation in a larger, international, randomized, quadri-blind trial against a placebo.


Athens Medical Society


Data Availability Statement

Study can be find at the website; ID NCT04902183. The dataset supporting the conclusions of this article is available upon request from corresponding author.The data is available upon request from corresponding author.


The original article is available at

Published Citation

Grigoropoulos I. et al. The safety and potential efficacy of exosomes overexpressing CD24 (EXO-CD24) in mild-moderate COVID-19 related ARDS. Respir Res. 2024;25(1):151.

Publication Date

1 April 2024

PubMed ID



  • School of Pharmacy and Biomolecular Sciences


Biomed Central


  • Published Version (Version of Record)