Evaluation of Xa inhibitors as potential inhibitors of the SARS-CoV-2 Mpro protease

Based on previous large-scale in silico screening several factor Xa inhibitors were proposed to potentially inhibit SARS-CoV-2 Mpro. In addition to their known anticoagulants activity this potential inhibition could have an additional therapeutic effect on patients with COVID-19 disease. In this study we examined the binding of the Apixaban, Betrixaban and Rivaroxaban to the SARS-CoV-2 Mpro with the use of the MicroScale Thermophoresis technique. Our results indicate that the experimentally measured binding affinity is weak and the therapeutic effect due to the SARS-CoV-2 Mpro inhibition is rather negligible.

The Role of Factor Xa-Independent Pathway and Anticoagulant Therapies in Cancer-Related Stroke

Background: The optimal strategy for stroke prevention in cancer patients is unknown. We compared the underlying mechanisms of coagulopathy and the effects of anticoagulants in patients with active cancer and atrial fibrillation (AF). Methods: We retrospectively enrolled 46 consecutive patients with embolic stroke of unknown source and active cancer (cancer stroke). We consecutively screened patients with cancer patients without stroke (n = 29), AF stroke (n = 52), and healthy subjects (n = 28), which served as controls. Patients with cancer stroke were treated with either enoxaparin (a low-molecular-weight heparin) or a factor Xa inhibitor, and those with AF stroke were treated with factor Xa inhibitors. D-dimer, factor Xa, and circulating cell-free DNA (cfDNA), a marker of neutrophil extracellular traposis, were measured at both before and after anticoagulation. Results: In AF stroke, factor Xa activity and cfDNA and D-dimer levels were decreased by treatment with factor Xa inhibitors. In contrast, in cancer stroke, factor Xa activity was decreased, D-dimer levels were unchanged, and cfDNA levels were increased by treatment with factor Xa inhibitors. In cancer stroke patients treated with enoxaparin, D-dimer levels were decreased (p = 0.011) and cfDNA levels were unchanged. Conclusion: The anticoagulation effects of factor Xa inhibitors differed between cancer stroke and AF stroke.

Factor Xa Inhibitors for Patients after Mechanical Heart Valve Replacement?

Patients with a mechanical heart valve need a lifelong anticoagulation due to the increased risk of valve thrombosis and thrombo-embolism. Currently, vitamin K antagonists (VKA) are the only approved class of oral anticoagulants, but relevant interactions and side effects lead to a large number of patients not achieving the optimal therapeutic target international normalized ration (INR). Therefore, steady measurements of the INR are imperative to ensure potent anticoagulation within a distinctive range. Direct oral anticoagulants (DOACs) with newer agents could serve as a possible alternative to VKAs in this patient cohort. DOACs are approved for several indications, e.g., atrial fibrillation (AF). They only have a minor interaction potential, which is why monitoring is not needed. Thereby, DOACs improve the livability of patients in need of chronical anticoagulation compared with VKAs. In contrast to dual platelet inhibition using aspirin in combination with an ADP receptor antagonist and the direct thrombin inhibitor dabigatran, the oral factor Xa inhibitors apixaban and rivaroxaban show promising results according to current evidence. In small-scale studies, factor Xa inhibitors were able to prevent thrombosis and thrombo-embolic events in patients with mechanical heart valves. Finally, DOACs seem to represent a feasible treatment option in patients with mechanical heart valves, but further studies are needed to evaluate clinical safety. In addition to the ongoing PROACT Xa trial with apixaban in patients after aortic On-X valve implantation, studies in an all-comer collective with rivaroxaban could be promising.

Factor Xa inhibitor for venous thromboembolism management in patient with cancer: a systematic review and meta-analysis

Background: An earlier systematic review reported no differences in the incidence of recurrent venous thromboembolism and major bleeding between factor Xa inhibitors and standard anticoagulation. The present meta-analysis aimed to assess the effectiveness of factor Xa inhibitors for the management of venous thromboembolism (VTE), specifically in patients with cancer, as there were more randomized clinical trials (RCTs) available. Methods: The PubMed and Cochrane Library databases were systematically screened for all RCTs assessing factor Xa inhibitor efficacy for VTE management in cancer patients. Using RevMan 5.3, we performed a Mantel–Haenszel fixed-effects meta-analysis of the following outcomes: recurrent VTE, VTE events, and major bleeding rates. Results: We identified 11 studies involving 7,965 patients. Factor Xa inhibitors were superior in preventing VTE recurrence, compared to low-molecular-weight heparin (LMWH) (OR 0.60; 95% CI 0.45–0.80; P < 0.01) and vitamin K antagonists (VKA) (OR 0.51; 95% CI 0.33–0.78; P < 0.01). As prophylaxis, factor Xa inhibitors had a similar rate of VTE compared to VKAs (OR 1.08 [95% CI 0.31–3.77]; P = 0.90) and a lower rate compared to placebo (OR 0.54 [95% CI 0.35–0.81]; P < 0.01). Major bleeding rates were higher with factor Xa inhibitors than with LMWHs (OR 1.34 [95% CI 0.83–2.18]; P = 0.23), but significantly lower than VKAs (OR 0.71 [95% CI 0.55–0.92]; P < 0.01). Conclusions: Factor Xa inhibitors are effective for VTE management in patients with cancer; however, they are also associated with an increased bleeding risk compared to LMWH, but decreased when compared to VKA.

Global research status and trends in venous thromboembolism after hip or knee arthroplasty from 1990 to 2021: a new perspective (Preprint)

BACKGROUND Venous thromboembolism (VTE) after hip or knee arthroplasty has attracted increasing attention over the past few decades. However, there is no bibliometric report on the publications in this field. OBJECTIVE The purpose of this study was to analyze the global research status, hotspots, and trends in VTE after arthroplasty. METHODS All articles about VTE research after hip or knee arthroplasty from 1990 to 2021 were retrieved from the Web of Science Core Collection database. The information of each article including citation, title, author, journal, country, institution, and keywords, was extracted for bibliometric analysis. RESULTS A total of 1,245 original articles from 53 countries and 603 institutions were retrieved. The number of publications showed a rising trend, with the largest contributions made by the USA. McMaster University in Canada was the leading institution for publications. The most productive author in this field was Eriksson BI, followed by Lassen MR and Dahl OE. The journals with the highest output and highest citation were the Journal of Arthroplasty and the Thrombosis and Haemostasis, respectively. The research hotspots switched from VTE diagnosis and heparin to factor Xa inhibitors (fondaparinux, rivaroxaban, apixaban) and direct thrombin inhibitors (dabigatran etexilate, ximelagatran), and finally to aspirin, risk factor studies, which can be observed from the keyword analysis and co-cited reference cluster analysis. CONCLUSIONS Over the past few decades, the understanding of VTE after hip or knee arthroplasty has been improved significantly. VTE prophylaxis agents have attracted tremendous attention, including warfarin, low molecular weight heparin, oral direct factor Xa inhibitors, oral direct thrombin inhibitors, and aspirin. These studies exert a critical influence on decision-making and management for VTE. Additionally, individualized VTE prevention based on risk factors for each patient and the development of new safe, effective, and inexpensive oral agents will be emerging trends in the future.