An ACAT inhibitor regulates SARS-CoV-2 replication and antiviral T cell activity (preprint)

The severity of disease following infection with SARS-CoV-2 is determined by viral replication kinetics and host immunity, with early T cell responses and/or suppression of viraemia driving a favourable outcome. Recent studies have uncovered a role for cholesterol metabolism in the SARS-CoV-2 life cycle and in T cell function. Here we show that blockade of the enzyme Acyl-CoA:cholesterol acyltransferase (ACAT) with Avasimibe inhibits SARS-CoV-2 entry and fusion independent of transmembrane protease serine 2 expression in multiple cell types. We also demonstrate a role for ACAT in regulating SARS-CoV-2 RNA replication in primary bronchial epithelial cells. Furthermore, Avasimibe boosts the expansion of functional SARS-CoV-2-specific T cells from the blood of patients sampled in the acute phase of infection. Thus, re-purposing of available ACAT inhibitors provides a compelling therapeutic strategy for the treatment of COVID-19 to achieve both antiviral and immunomodulatory effects.

A randomised clinical trial of azithromycin versus standard care in ambulatory COVID-19 - the ATOMIC2 trial (preprint)

Background The antibacterial, anti-inflammatory and antiviral properties of azithromycin suggest therapeutic potential against COVID-19. Randomised data in mild-moderate disease are lacking. We assessed whether azithromycin is effective in reducing hospitalisation in patients with mild-moderate COVID-19. Methods This open-label, randomised superiority clinical trial at 19 centres in the United Kingdom enrolled adults, [≥]18 years, presenting to hospitals with clinically-diagnosed highly-probable or confirmed COVID-19 infection, with <14 days symptoms, considered suitable for initial ambulatory management. Patients were randomised (1:1) to azithromycin (500 mg daily orally for 14 days) or to standard care without macrolides. The primary outcome was the difference in proportion of participants with death or hospital admission from any cause over the 28 days from randomisation, assessed according to intention-to-treat (ITT). Trial registration: ClinicalTrials.gov, NCT04381962, Study closed. Findings 298 participants were enrolled from 3rd June 2020 to 29th January 2021. The primary outcome was assessed in 292 participants. The primary endpoint was not significantly different between the azithromycin and control groups (Adjusted OR 0.91 [95% CI 0.43-1.92], p=0.80). Rates of respiratory failure, progression to pneumonia, all-cause mortality, and adverse events, including serious cardiovascular events, were not significantly different between groups. Interpretation In patients with mild-moderate COVID-19 managed without hospital admission, adding azithromycin to standard care treatment did not reduce the risk of subsequent hospitalisation or death. Our findings do not support the use of azithromycin in patients with mild-moderate COVID-19. Funding NIHR Oxford BRC, University of Oxford and Pfizer Inc.

A Randomised Clinical Trial of Azithromycin Versus Standard Care in Ambulatory COVID-19 – The ATOMIC2 Trial (preprint)

Background: The antibacterial, anti-inflammatory and antiviral properties of azithromycin suggest therapeutic potential against COVID-19. Randomised data in mild-moderate disease are lacking. We assessed whether azithromycin is effective in reducing hospitalisation in patients with mild-moderate COVID-19. Methods: This open-label, randomised superiority clinical trial at 19 centres in the United Kingdom enrolled adults, ≥18 years, presenting to hospitals with clinically-diagnosed highly-probable or confirmed COVID-19 infection, with <14 days symptoms, considered suitable for initial ambulatory management. Patients were randomised (1:1) to azithromycin (500 mg daily orally for 14 days) or to standard care without macrolides. The primary outcome was the difference in proportion of participants with death or hospital admission from any cause over the 28 days from randomisation, assessed according to intention-to-treat (ITT). Trial registration: ClinicalTrials.gov, NCT04381962, Study closed. Findings: 298 participants were enrolled from 3 rd June 2020 to 29 th January 2021. The primary outcome was assessed in 292 participants. The primary endpoint was not significantly different between the azithromycin and control groups (Adjusted OR 0·91 [95% CI 0·43-1·92], p=0·80). Rates of respiratory failure, progression to pneumonia, all-cause mortality, and adverse events, including serious cardiovascular events, were not significantly different between groups. Interpretation: In patients with mild-moderate COVID-19 managed without hospital admission, adding azithromycin to standard care treatment did not reduce the risk of subsequent hospitalisation or death. Our findings do not support the use of azithromycin in patients with mild-moderate COVID-19. Trial Registration: This trial was registered with ClinicalTrials.gov (NCT04381962) and EudraCT (2020-001740-26).Funding: NIHR Oxford BRC, University of Oxford and Pfizer Inc.Declaration of Interests: TSCH has received grants from Pfizer Inc., grants from University of Oxford, grants from the Wellcome Trust, grants from The Guardians of the Beit Fellowship, and grants from the NIHR Oxford Biomedical Research Centre during the conduct of the study; and personal fees from Astra Zeneca, personal fees from TEVA, personal fees from Peer Voice outside the submitted work. MJ has received grants from the University of Oxford and NIHR Oxford Biomedical Research Centre. DR has undertaken paid consultancy for GSK outside the submitted work. IDP reports personal fees from AstraZeneca, Boehringer Ingelheim, Aerocrine, Almirall, Novartis, GlaxoSmithKline, Genentech, Regeneron, Teva, Chiesi, Sanofi, Circassia, Knopp, and grants from NIHR outside the submitted work. JU has received honoraria for preparation of educational materials and has served on an advisory board for Gilead Sciences and ViiV Healthcare outside of the submitted work. LC, RK, AW, JLC, VSB, JB, SJD, JM, PM, RG, TB, GJ, FC, DC, SE, DL and SM declare they have no competing interests.Ethics Approval Statement: The trial protocol was reviewed and approved by the UK Medicines and Healthcare products Regulatory Agency and an independent ethical committee (London – Brent Research Ethics Committee, Research Ethics Committee reference number 20/HRA/2105).

Circadian regulation of SARS-CoV-2 infection in lung epithelial cells (preprint)

The COVID-19 pandemic, caused by SARS-CoV-2 coronavirus, is a global health issue with unprecedented challenges for public health. SARS-CoV-2 primarily infects cells of the respiratory tract, via binding human angiotensin-converting enzyme (ACE2), and infection can result in pneumonia and acute respiratory distress syndrome. Circadian rhythms coordinate an organisms response to its environment and recent studies report a role for the circadian clock to regulate host susceptibility to virus infection. Influenza A infection of arhythmic mice, lacking the circadian component BMAL1, results in higher viral replication and elevated inflammatory responses leading to more severe bronchitis, highlighting the impact of circadian pathways in respiratory function. We demonstrate circadian regulation of ACE2 in lung epithelial cells and show that silencing BMAL1 or treatment with the synthetic REV-ERB agonist SR9009 reduces ACE2 expression and inhibits SARS-CoV-2 entry and RNA replication. Treating infected cells with SR9009 limits viral replication and secretion of infectious particles, showing that post-entry steps in the viral life cycle are influenced by the circadian system. Our study suggests new approaches to understand and improve therapeutic targeting of COVID-19.

Hypoxic and Pharmacological Activation of HIF Inhibits SARS-CoV-2 Infection of Lung Epithelial Cells (preprint)

COVID-19, caused by the novel coronavirus SARS-CoV-2, is a global health issue with more than 1 million fatalities to date. Understanding how host factors modify the viral life cycle could inform susceptibility to viral infection and the design of new therapies. Viral replication is shaped by the cellular microenvironment and one important factor is local oxygen tension, where hypoxia inducible factor (HIF) regulates transcriptional responses to hypoxia. SARS-CoV-2 primarily infects cells of the respiratory tract, entering via its Spike glycoprotein binding to angiotensin-converting enzyme (ACE2). We demonstrate that hypoxia and the HIF prolyl hydroxylase inhibitor Roxadustat (FG-4592) reduce ACE2 expression and inhibit SARS-CoV-2 entry and replication in lung epithelial cells via a HIF-1α dependent signalling pathway. Further, hypoxia and Roxadustat inhibit viral replication in SARS-CoV-2 infected cells, showing that post-entry steps in the viral life cycle are oxygen-sensitive. This study highlights the importance of hypoxia and HIF signalling in regulating multiple aspects of SARS-CoV-2 infection and raises the potential use of HIF prolyl hydroxylase inhibitors in the prevention and/or treatment of COVID-19.Funding: The McKeating laboratory is funded by a Wellcome Investigator Award (IA) 200838/Z/16/Z, UK Medical Research Council (MRC) project grant MR/R022011/1 and Chinese Academy of Medical Sciences (CAMS) Innovation Fund for Medical Science (CIFMS), China (grant number: 2018-I2M-2-002). The Ratcliffe laboratory is funded by the Oxford Branch of the Ludwig Institute for Cancer Research; Wellcome IA 106241/Z/14/Z; the Francis Crick Institute, which receives core funding from Cancer Research UK (FC001501), UK MRC (FC001501) and Wellcome (FC001501); the Paradifference Foundation. PJR, EJH and TB are additionally funded by the COVID-19 Research Response Fund, University of Oxford. SK is funded by the Clarendon Scholarships Fund and the Christopher Welch Trust. The Davis laboratory is funded by Wellcome IA 209412/Z/17/Z and Wellcome Strategic Awards 091911/B/10/Z and 107457/Z/15/Z. JYL is funded by the Medial Sciences Graduate Studentship, University of Oxford. The Hinks laboratory is funded by grants from the Wellcome (104553/z/14/z, 211050/Z/18/z) and the National Institute for Health Research (NIHR) Oxford Biomedical Research Centre; the views expressed are those of the authors and not those of the NHS or NIHR. Conflict of Interest: EJH is employed under the Cambridge Experimental Medicine Initiative, which is partly funded by AstraZeneca although they have not been involved in this project. The other authors declare no financial interests.Ethical Approval: The study was reviewed by the Oxford Research Ethics Committee B (18/SC/0361).