ABSTRACT
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).
ABSTRACT
Background : Markers of both inflammation and coagulation are linked to clinical outcome in coronavirus disease 2019 (COVID-19). Binding of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to the angiotensin-converting enzyme 2 receptor, which is involved in kinin breakdown, interferes with the kallikreinkinin pathway. This could result in increased vascular permeability, fluid excess in the lungs and pulmonary edema. Furthermore, the kallikrein-kinin pathway links coagulation and inflammation through its interactions with the contact activation pathway of coagulation via factor XII and with neutrophil extracellular traps (NETs). These insights could help to explain the clinical presentation of COVID-19 pneumonia with pulmonary coagulopathy and the high incidence of thromboembolic complications in COVID-19. Aims : Given the lack of clinical evidence to support this hypothesis, we studied the kallikrein-kinin system in bronchoalveolar lavage (BAL) fluid. Methods : In BAL fluid samples from patients with or without COVID-19, we performed in-depth analyses of kinin peptides (bradykinin, Lys-bradykinin, Lys-bradykinin-(1-8), bradykinin-(1-8), bradykinin-(1-7), and bradykinin-(1-5)) using a liquid chromatography with tandem mass spectrometry assay, along with measurements of plasma and tissue kallikrein hydrolytic activity and myeloperoxidase (MPO)-DNA complexes as a biomarker for NETs. Informed consent and ethical approval were obtained. Results : We observed higher levels of the most downstream kinin peptide bradykinin-(1-5) (Figure 1), higher tissue kallikrein activity (Figure 2), and higher levels of MPO-DNA complexes (699.0 ng/mL [66.0-142621.0], median [range], n = 21 vs 70.5 [9.9-960.0], n = 19;P < 0.001) in BAL fluid from patients with COVID-19 compared to those in BAL fluid from patients without COVID-19. Conclusions : Our data support the hypothesis that SARS-CoV-2 induces dysregulation of the kallikrein-kinin system, which contributes to thromboinflammation in COVID-19. These findings encourage the investigation of drugs that target the kallikrein-kinin system as a potential treatment option for patients with COVID-19.
ABSTRACT
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.