Regadenoson for the treatment of COVID-19: A five case clinical series and mouse studies

PLOS ONE, Aug 2023

Background Adenosine inhibits the activation of most immune cells and platelets. Selective adenosine A2A receptor (A2AR) agonists such as regadenoson (RA) reduce inflammation in most tissues, including lungs injured by hypoxia, ischemia, transplantation, or sickle cell anemia, principally by suppressing the activation of invariant natural killer T (iNKT) cells. The anti-inflammatory effects of RA are magnified in injured tissues due to induction in immune cells of A2ARs and ecto-enzymes CD39 and CD73 that convert ATP to adenosine in the extracellular space. Here we describe the results of a five patient study designed to evaluate RA safety and to seek evidence of reduced cytokine storm in hospitalized COVID-19 patients. Methods and findings Five COVID-19 patients requiring supplemental oxygen but not intubation (WHO stages 4–5) were infused IV with a loading RA dose of 5 μg/kg/h for 0.5 h followed by a maintenance dose of 1.44 μg/kg/h for 6 hours, Vital signs and arterial oxygen saturation were recorded, and blood samples were collected before, during and after RA infusion for analysis of CRP, D-dimer, circulating iNKT cell activation state and plasma levels of 13 proinflammatory cytokines. RA was devoid of serious side effects, and within 24 hours from the start of infusion was associated with increased oxygen saturation (93.8 ± 0.58 vs 96.6 ± 1.08%, P<0.05), decreased D-dimer (754 ± 17 vs 518 ± 98 ng/ml, P<0.05), and a trend toward decreased CRP (3.80 ± 1.40 vs 1.98 ± 0.74 mg/dL, P = 0.075). Circulating iNKT cells, but not conventional T cells, were highly activated in COVID-19 patients (65% vs 5% CD69+). RA infusion for 30 minutes reduced iNKT cell activation by 50% (P<0.01). RA infusion for 30 minutes did not influence plasma cytokines, but infusion for 4.5 or 24 hours reduced levels of 11 of 13 proinflammatory cytokines. In separate mouse studies, subcutaneous RA infusion from Alzet minipumps at 1.44 μg/kg/h increased 10-day survival of SARS-CoV-2-infected K18-hACE2 mice from 10 to 40% (P<0.001). Conclusions Infused RA is safe and produces rapid anti-inflammatory effects mediated by A2A adenosine receptors on iNKT cells and possibly in part by A2ARs on other immune cells and platelets. We speculate that iNKT cells are activated by release of injury-induced glycolipid antigens and/or alarmins such as IL-33 derived from virally infected type II epithelial cells which in turn activate iNKT cells and secondarily other immune cells. Adenosine released from hypoxic tissues, or RA infused as an anti-inflammatory agent decrease proinflammatory cytokines and may be useful for treating cytokine storm in patients with Covid-19 or other inflammatory lung diseases or trauma.

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Regadenoson for the treatment of COVID-19: A five case clinical series and mouse studies

PLOS ONE RESEARCH ARTICLE Regadenoson for the treatment of COVID-19: A five case clinical series and mouse studies Joseph Rabin1☯, Yunge Zhao1☯, Ezzat Mostafa1, Manal Al-Suqi1, Emily Fleischmann1, Mark R. Conaway ID2, Barbara J. Mann3, Preeti Chhabra ID4, Kenneth L. Brayman4, Alexander Krupnick1, Joel Linden1,3*, Christine L. Lau ID1* 1 Department of Surgery, Division of Thoracic, University of Maryland, Baltimore, Maryland, United States of America, 2 Department of Public Health Sciences, University of Virginia, Charlottesville, Virginia, United States of America, 3 Department of Medicine, Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, Virginia, United States of America, 4 Department of Surgery, University of Virginia, Charlottesville, Virginia, United States of America a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 ☯ These authors contributed equally to this work. * (CLL); (JL) Abstract Background OPEN ACCESS Citation: Rabin J, Zhao Y, Mostafa E, Al-Suqi M, Fleischmann E, Conaway MR, et al. (2023) Regadenoson for the treatment of COVID-19: A five case clinical series and mouse studies. PLoS ONE 18(8): e0288920. https://doi.org/10.1371/journal. pone.0288920 Editor: Emily Chenette, PLOS (Public Library of Science), UNITED KINGDOM Adenosine inhibits the activation of most immune cells and platelets. Selective adenosine A2A receptor (A2AR) agonists such as regadenoson (RA) reduce inflammation in most tissues, including lungs injured by hypoxia, ischemia, transplantation, or sickle cell anemia, principally by suppressing the activation of invariant natural killer T (iNKT) cells. The antiinflammatory effects of RA are magnified in injured tissues due to induction in immune cells of A2ARs and ecto-enzymes CD39 and CD73 that convert ATP to adenosine in the extracellular space. Here we describe the results of a five patient study designed to evaluate RA safety and to seek evidence of reduced cytokine storm in hospitalized COVID-19 patients. Received: June 24, 2022 Accepted: July 4, 2023 Published: August 11, 2023 Peer Review History: PLOS recognizes the benefits of transparency in the peer review process; therefore, we enable the publication of all of the content of peer review and author responses alongside final, published articles. The editorial history of this article is available here: https://doi.org/10.1371/journal.pone.0288920 Copyright: © 2023 Rabin et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All relevant data are within the manuscript, its Supporting Information files and the supplemental data files. Methods and findings Five COVID-19 patients requiring supplemental oxygen but not intubation (WHO stages 4–5) were infused IV with a loading RA dose of 5 μg/kg/h for 0.5 h followed by a maintenance dose of 1.44 μg/kg/h for 6 hours, Vital signs and arterial oxygen saturation were recorded, and blood samples were collected before, during and after RA infusion for analysis of CRP, D-dimer, circulating iNKT cell activation state and plasma levels of 13 proinflammatory cytokines. RA was devoid of serious side effects, and within 24 hours from the start of infusion was associated with increased oxygen saturation (93.8 ± 0.58 vs 96.6 ± 1.08%, P<0.05), decreased D-dimer (754 ± 17 vs 518 ± 98 ng/ml, P<0.05), and a trend toward decreased CRP (3.80 ± 1.40 vs 1.98 ± 0.74 mg/dL, P = 0.075). Circulating iNKT cells, but not conventional T cells, were highly activated in COVID-19 patients (65% vs 5% CD69+). RA infusion for 30 minutes reduced iNKT cell activation by 50% (P<0.01). RA infusion for 30 minutes did not influence plasma cytokines, but infusion for 4.5 or 24 hours reduced levels of 11 of 13 proinflammatory cytokines. In separate mouse studies, subcutaneous RA infusion from Alzet minipumps at 1.44 μg/kg/h increased 10-day survival of SARS-CoV-2infected K18-hACE2 mice from 10 to 40% (P<0.001). PLOS ONE | https://doi.org/10.1371/journal.pone.0288920 August 11, 2023 1 / 19 PLOS ONE Funding: This study is supported by the following funding sources: Specific grant number: Award Number: R01HL128492-05S1 Initials of authors who received the award: CLL Full names of commercial companies that funded the study: NHLBI Division of Intramural Research Initials of authors who received salary: YZ, EM, MA, MRC, BJM, JL, CLL URLs to sponsors’ websites: https:// www.nhlbi.nih.gov/about/divisions/divisionintramural-research Specific grant number: Award Number: MC10 Initials of authors who received the award: JL Full names of commercial companies that funded the study: Manning Fund Initials of authors who received salary: JL, BJM, KLB, PC URLs to sponsors’ websites: Manning Family Foundation (themanningfamilyfoundation.org) Specific grant number: Award Number: ISR005923 Initials of authors who received the award: CLL Full names of commercial companies that funded the study: Astellas Pharma US Initials of authors who received salary: This funding did not pay any author any salary URLs to sponsors’ websites: Astellas Pharma US | Changing Tomorrow | Home Specific grant number: Award Number: R01AI145108 Initials of authors who received the award: AK Full names of commercial companies that funded the study: Division of Microbiology and Infectious Diseases, National Institute of Allergy and Infectious Diseases Initials of authors who received salary: AK URLs to sponsors’ websites: Division of Microbiology and Infectious Diseases | NIH: National Institute of Allergy and Infectious Diseases Specific grant number: Award Number: P01 AI116501 Initials of authors who received the award: AK Full names of commercial companies that funded the study: Division of Microbiology and Infectious Diseases, National Institute of Allergy and Infectious Diseases Initials of authors who received salary: AK URLs to sponsors’ websites: Division of Microbiology and Infectious Diseases | NIH: National Institute of Allergy and Infectious Diseases We affirmed that the above sponsors or funders played NO role in: Study design, Data collection and analysis, Decision to publish, Preparation of the manuscript of this study. Competing interests: The authors have declared that no competing interests exist. Regadenoson for the treatment of COVID-19 Conclusions Infused RA is safe and produces rapid anti-inflammatory effects mediated by A2A adenosine receptors on iNKT cells and possibly in part by A2ARs on other immune cells and platelets. We speculate that iNKT cells are activated by release of injury-induced glycolipid antigens and/or alarmins such as IL-33 derived from virally infected type II epithelial cells which in turn activate iNKT cells and secondarily other immune cells. Adenosine released from hypoxic tissues, or RA infuse (...truncated)


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Joseph Rabin, Yunge Zhao, Ezzat Mostafa, Manal Al-Suqi, Emily Fleischmann, Mark R. Conaway, Barbara J. Mann, Preeti Chhabra, Kenneth L. Brayman, Alexander Krupnick, Joel Linden, Christine L. Lau. Regadenoson for the treatment of COVID-19: A five case clinical series and mouse studies, PLOS ONE, 2023, Volume 18, Issue 8, DOI: 10.1371/journal.pone.0288920