Modulation of thromboinflammation in hospitalized COVID-19 patients with aprotinin, low molecular weight heparin, and anakinra: the DAwn- AntiCo study

Background/Introduction: Thromboinflammation in severe COVID-19 is associated with disease severity and outcome. The kallikrein pathway is suggested to mediate thromboinflammation in COVID-19 by activating inflammatory pathways and contactmediated coagulation. Purpose(s): The DAWn-antico study investigates if a multitarget modulation of the thromboinflammatory response improves outcomes in hospitalized patients with severe COVID-19. Method(s): In this multicenter open-label randomized clinical trial (EudraCT 2020-001739-28), patients hospitalized with COVID- 19 were 1:2 randomized to receive standard of care (SOC) or SOC plus study intervention. The intervention consisted of aprotinin (2,000,000 IE IV four times daily) combined with low-molecular-weight heparin (LMWH;SC 50 IU/kg twice daily at the ward, 75 IU/kg twice daily at intensive care). Additionally, patients with predefined hyperinflammation received the interleukin-1- receptor antagonist anakinra (100mg IV four times daily). The primary outcome was time to a sustained 2-point improvement on the 7-point WHO ordinal scale for clinical status, or discharge. The trial was funded by Life Sciences Research Partners, Research Foundation Flanders (G0G4720N), and KU Leuven COVID-19 fund. Result(s): Between 24 June 2020 and 01 February 2021, 105 patients were randomized, and 102 patients were included in the full analysis set (intervention N=67 vs. SOC N=35). Twenty-five patients from the intervention group (37%) received anakinra. The intervention did not affect the primary outcome (HR 0.77 [CI 0.50;1.19], p=0.24) or mortality (intervention n=3 (4.6%) vs. SOC n=2 (5.7%), HR 0.82, [CI 0.14;4.94], p=0.83). There was one treatment-related adverse event in the intervention group (hematuria, 1.49%). There was one thrombotic event in the intervention group (1.49%) and one in the SOC group (2.86%), but no major bleedings. Conclusion(s): In hospitalized COVID-19 patients, modulation of thromboinflammation with high-dose aprotinin and LMWH with or without anakinra did not improve outcome in patients with moderate to severe COVID-19. (Disclosure: this RCT was presented at ISTH 2022 in London and will be published in Research and Practise in Thrombosis and Haemostasis).

Monocyte-driven atypical cytokine storm and aberrant neutrophil activation as key mediators of COVID-19 disease severity.

Epidemiological and clinical reports indicate that SARS-CoV-2 virulence hinges upon the triggering of an aberrant host immune response, more so than on direct virus-induced cellular damage. To elucidate the immunopathology underlying COVID-19 severity, we perform cytokine and multiplex immune profiling in COVID-19 patients. We show that hypercytokinemia in COVID-19 differs from the interferon-gamma-driven cytokine storm in macrophage activation syndrome, and is more pronounced in critical versus mild-moderate COVID-19. Systems modelling of cytokine levels paired with deep-immune profiling shows that classical monocytes drive this hyper-inflammatory phenotype and that a reduction in T-lymphocytes correlates with disease severity, with CD8+ cells being disproportionately affected. Antigen presenting machinery expression is also reduced in critical disease. Furthermore, we report that neutrophils contribute to disease severity and local tissue damage by amplification of hypercytokinemia and the formation of neutrophil extracellular traps. Together our findings suggest a myeloid-driven immunopathology, in which hyperactivated neutrophils and an ineffective adaptive immune system act as mediators of COVID-19 disease severity.

A randomized, open-label, adaptive, proof-of-concept clinical trial of modulation of host thromboinflammatory response in patients with COVID-19: the DAWn-Antico study.

BACKGROUND: The peak of the global COVID-19 pandemic has not yet been reached, and many countries face the prospect of a second wave of infections before effective vaccinations will be available. After an initial phase of viral replication, some patients develop a second illness phase in which the host thrombotic and inflammatory responses seem to drive complications. Severe COVID-19 disease is linked to high mortality, hyperinflammation, and a remarkably high incidence of thrombotic events. We hypothesize a crucial pathophysiological role for the contact pathway of coagulation and the kallikrein-bradykinin pathway. Therefore, drugs that modulate this excessive thromboinflammatory response should be investigated in severe COVID-19. METHODS: In this adaptive, open-label multicenter randomized clinical trial, we compare low molecular weight heparins at 50 IU anti-Xa/kg twice daily-or 75 IU anti-Xa twice daily for intensive care (ICU) patients-in combination with aprotinin to standard thromboprophylaxis in hospitalized COVID-19 patients. In the case of hyperinflammation, the interleukin-1 receptor antagonist anakinra will be added on top of the drugs in the interventional arm. In a pilot phase, the effect of the intervention on thrombotic markers (D-dimer) will be assessed. In the full trial, the primary outcome is defined as the effect of the interventional drugs on clinical status as defined by the WHO ordinal scale for clinical improvement. DISCUSSION: In this trial, we target the thromboinflammatory response at multiple levels. We intensify the dose of low molecular weight heparins to reduce thrombotic complications. Aprotinin is a potent kallikrein pathway inhibitor that reduces fibrinolysis, activation of the contact pathway of coagulation, and local inflammatory response. Additionally, aprotinin has shown in vitro inhibitory effects on SARS-CoV-2 cellular entry. Because the excessive thromboinflammatory response is one of the most adverse prognostic factors in COVID-19, we will add anakinra, a recombinant interleukin-1 receptor antagonist, to the regimen in case of severely increased inflammatory parameters. This way, we hope to modulate the systemic response to SARS-CoV-2 and avoid disease progressions with a potentially fatal outcome. TRIAL REGISTRATION: The EU Clinical Trials Register 2020-001739-28 . Registered on April 10, 2020.

Anticoagulant therapy in COVID-19 critically ill: Should we go for more?

Critically ill COVID-19 patients often develop a severe pro-thrombotic milieu, as reflected by the markedly increased d-dimer levels. Several cohort studies have reported high rates of thrombotic complications, including deep venous thrombosis (DVT) and pulmonary embolism (PE), myocardial infarction, stroke and microvascular thrombosis. Accordingly, COVID-19 patients who are hospitalized either at a normal, non-intensive care unit (ICU) or at the ICU need to receive appropriate dosages of anticoagulant therapy to prevent or treat these thrombotic complications. This manuscript summarizes the institutional guidance for the antithrombotic prophylaxis and treatment of VTE as outlined by a multidisciplinary team of experts during the first weeks of the COVID-19 pandemic in Europe. Controlled studies are needed to verify the optimal anticoagulation for both prophylaxis and treatment.