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Introduction Patients hospitalized for acute ischemic stroke have an increased risk of venous thromboembolism (VTE) that may persist beyond the currently recommended period of 6 to 14 days of thromboprophylaxis. This systematic review evaluated the efficacy and safety of extended venous thromboprophylaxis in patients hospitalized for acute ischemic stroke. Materials and methods MEDLINE, EMBASE and Clinicaltrials.gov were searched up to December 2020 for randomized controlled trials comparing extended versus standard venous thromboprophylaxis in patients hospitalized for acute ischemic stroke. The efficacy outcome was a composite of asymptomatic or symptomatic deep vein thrombosis, symptomatic pulmonary embolism, and VTE-related death. The safety outcome was major bleeding. Summary risk ratios (RRs) with corresponding 95% confidence intervals (CIs) were calculated using random-effects models. Results Four randomized controlled trials enrolling 33718 patients were included. Of 4330 (12.8%) patients hospitalized for acute ischemic stroke, 2152 (49.7%) received extended thromboprophylaxis for four to five weeks with betrixaban (n = 405, 18.8%), enoxaparin (n = 198, 9.2%), or rivaroxaban (n = 1549, 72.0%), and 2178 (50.3%) received standard venous thromboprophylaxis with enoxaparin. VTE risk was lower in acute ischemic stroke patients receiving extended thromboprophylaxis (RR 0.67; 95% CI, 0.43 to 1.04; 13 fewer per 1000), whereas the increase in major bleeding seemed trivial when compared with standard prophylaxis (RR 1.10; 95% CI, 0.31 to 3.95; 1 more per 1000). Conclusion In patients hospitalized for acute ischemic stroke, the net clinical benefit may favor extended venous thromboprophylaxis for four to five weeks over standard thromboprophylaxis.

Objectives Monitoring is essential to safe anticoagulation prescribing and requires close collaboration among pathologists, clinicians, and pharmacists. Methods We describe our experience in the evolving strategy for laboratory testing of unfractionated heparin (UFH). Results An intrainstitutional investigation revealed significant discordance between activated partial thromboplastin time (aPTT) and antifactor Xa (anti-Xa) assays, prompting a transition from the former to the latter in 2013. With the increasing use of oral factor Xa inhibitors (eg, apixaban, rivaroxaban, edoxaban, betrixaban), which interfere with the anti-Xa assay, we adapted our protocol again to incorporate aPTT in patients admitted on oral Xa inhibitors who require transition to UFH. Conclusions Our experience demonstrates key challenges in anticoagulation and highlights the importance of clinical pathologists in helping health systems adapt to the changing anticoagulation landscape.

A simple, accurate, rapid and sensitive reversed-phase high-performance liquid chromatography (RP-HPLC) method was established for determination of a novel non-vitamin K antagonist oral anticoagulant drug, betrixaban, and its co-administered calcium-channel blocker drug, lercanidipine, in pharmaceutical formulations and biological fluids. The proposed HPLC method was the first chromatographic method applied to estimate this mixture in a short chromatographic run (

Venous thromboembolism (VTE) is a known cause of morbidity and mortality, especially among acutely ill medical patients. Although VTE prophylaxis is part of post-discharge clinical care in surgical patients, there is controversy regarding its use in acutely ill medical patients and the current guideline statements suggest against its routine use. Recent clinical trials (APEX, MAGELLAN and MARINER) compared the safety and efficacy of direct oral anticoagulants (including betrixaban and rivaroxaban) with the standard of the care, enoxaparin, to identify the risk–benefit tradeoff. In this review, we summarized the key findings from these trials and substudies and recent updates in society guidelines regarding VTE prevention. In addition, we discussed the potential barriers, cost-effectiveness, and COVID-19 with respect to the implementation of extended-duration or post-discharge usage of direct oral anticoagulants.

Achieving the desired solubility and dissolution of active pharmaceutical ingredients (APIs) continues to be a big challenge in the pharmaceutical industry. In this regard, multicomponent solids of APIs such as salts and cocrystals have shown significant promise in resolving such solubility/dissolution issues. However, very little is known on how the APIs' solubility or dissolution is affected by the drug to coformer ratio in multicomponent solids. Betrixaban, is an anticoagulant drug approved in 2017 for the prevention of venous thromboembolism. During the alternate solid form development studies of the known betrixaban maleate, a rare multicomponent solid form, salt-cocrystal hydrate of betrixaban, was discovered and characterized thoroughly by spectroscopic, thermal, and X-ray crystallographic methods. Significantly, the new betrixaban maleate maleic acid hydrate (1:1:2:1) form has shown lower melting point (80 °C) as compared to its parent salt (197.5 °C). From such a large melting difference (117 °C) between the salt and salt-cocrystal hydrate of API, we anticipated substantially better solubility for the salt-cocrystal hydrate (low enthalpy). Furthermore, the predicted solubility also supported our anticipation. However, the powder dissolution tests at different pH conditions provided contrary results, that is, the salt-cocrystal hydrate showed 10 times lower solubility as compared to its salt. A detailed investigation, considering all the potential factors, revealed that "common-ion effect" could be a critical factor for the low solubility of the salt-cocrystal hydrate in which the API to coformer ratio is 1:3. To the best of our knowledge, this is the first case study on the solubility of pharmaceutical salt-cocrystal hydrates with an emphasis on "common-ion effect" or drug to coformer ratio.

Although the use of direct oral anticoagulants (DOACs) has been reported in patients with atrial fibrillation (AF), there is currently no consensus on the occurrence or characteristics of the hemorrhage risk in different antithrombotic regimens. Disproportionality and Bayesian analyses were performed in mining data of suspected hemorrhagic events after antithrombotic drug use from the FDA Adverse Event Reporting System (FAERS) from January 2004 to September 2019. The time to onset and fatality rate of hemorrhage following different antithrombotic regimens were also compared. A total of 84,998 reports of hemorrhage-related adverse events with the use of antithrombotic drugs were identified. The patients included were mostly from the Americas (80.87%) and Europe (13.22%), with most data submitted by nonhealthcare professionals. Among the seven antithrombotic drug monotherapies, betrixaban had the highest association with hemorrhage based on the highest reporting odds ratio (ROR, 829.95; 95% CI = 113.61-6063.15), proportional reporting ratio (PRR, 24.68, χ2 = 804.24), and multi-item gamma Poisson shrinker (MGPS, 24.68, 95% one-sided CI = 4.67). The combination therapies of clopidogrel plus new oral anticoagulants had higher RORs, PRRs, and empirical Bayesian geometric means (EBGMs) than the antithrombotic drug monotherapies. Hemorrhage associated with rivaroxaban plus clopidogrel appeared to have an earlier onset (171 days vs 219 days, 95% two-sided CI =68.68-27.34, p

Introduction Different coagulation indices for direct oral anticoagulants (DOACs) exist in clinical practice, but limited data are available for the diagnostic power of these indices. This review and meta-analysis aims to explore the diagnostic value of coagulation indices for DOACs. Materials and methods PubMed, Web of Science, EMBASE, Clinical Trials.gov , and the Cochrane Library were searched from inception of each database to 15 February 2020. Studies reporting a relationship between coagulation indices and the gold standard (liquid chromatography/tandem mass spectrometry) were included in the analysis. Results Sixteen articles from 9169 citations evaluating the performance of coagulation indices were included in this review. A total of 236, 273, 273 rivaroxaban samples were included to assess the diagnostic power of anti-Xa activity (AXA), prothrombin time (PT), combined PT and activated partial thromboplastin time, respectively. A total of 268 dabigatran samples were included to assess the diagnostic performance of diluted thromboplastin time (dTT). AXA calibrated by rivaroxaban showed a sensitivity of 0.98 (95% confidence interval (CI): 0.91–0.99) and a specificity of 0.98 (95% CI: 0.94–0.99) at the threshold of 30 ng/mL. For dabigatran, the combined sensitivity of dTT was 0.76 (95% CI: 0.66–0.84) and combined specificity was 0.97 (95% CI: 0.92–0.99). Conclusions DOAC-specific calibrated AXA was a good index to indicate concentration for rivaroxaban and apixaban. More studies on edoxaban and betrixaban are in need. Diluted TT, thrombin inhibitor assay, and ecarin-based assays were potential to measure dabigatran concentration. Due to the limited data, results should be validated in the future.

Ty J. Gluckman, MD, FACC, Chair Niti R. Aggarwal, MD, FACC Nicole M. Bhave, MD, FACC Gregory J. Dehmer, MD, MACC Olivia N. Gilbert, MD, MSc, FACC Chayakrit Krittanawong, MD Dharam J. Kumbhani, MD, SM, FACC Javier A. Sala-Mercado, MD, PhD Andrea L. Price, CPHQ, RCIS, AACC David E.

A new scalable route to synthesize the factor Xa (FXa) inhibitor betrixaban is disclosed. The product is obtained in a seven-step reaction sequence (in five stages using two one-pot reactions) starting from easily accessible 4-(N,N-dimethylcarbamimidoyl)benzoate. Effective isolation of intermediates, use of cost-effective amide formation and 2-methyltetrahydrofuran as an effective reaction solvent as well as for extraction in three of the stages, are key features. The strategy provides the desired product in 38% overall yield with high purity (>98%).

Venous thromboembolism (VTE) remains a major cause of morbidity and mortality in hospitalized medically ill patients. These patients constitute a heterogeneous population, whose VTE risk is dependent upon the acute medical illness, immobility status, and patient-specific risk factors that have been incorporated into individualized VTE risk assessment models. Randomized placebo-controlled trials (RCTs) have shown both efficacy and net clinical benefit of in-hospital thromboprophylaxis, which is supported by guideline recommendations. The data for extended posthospital discharge thromboprophylaxis are more nuanced. RCTs comparing standardized duration low-molecular weight heparin versus extended duration direct oral anticoagulants, such as betrixaban and rivaroxaban, have shown efficacy and net clinical benefit in select groups of high VTE and low-bleed risk populations of hospitalized medically ill patients. These oral agents are now approved for both in-hospital and extended thromboprophylaxis. However, the most recent guidelines do not recommend routine use of these agents for extended thromboprophylaxis. Longitudinal studies in medically ill patients have shown that the majority of VTE events occur in the posthospital discharge setting within 6 weeks of hospitalization. This, coupled with the short hospital length-of-stay and lack of routine postdischarge thromboprophylaxis in U.S. health care settings, has dampened quality improvement efforts aimed at reducing hospital-acquired VTE. The aim of this multidisciplinary document is to provide an evidence-based framework to guide clinicians in assessing VTE and bleeding risk in hospitalized medically ill patients using an individualized, risk-adapted, and patient-centered approach, with the aim of providing clinical pathways toward the use of appropriate type and duration of available thromboprophylactic agents.

Rivaroxaban 1 is an oxazolidinone derivative that is the first representative of a new series of anticoagulants,1,2 and it was soon followed by apixaban, betrixaban and darexaban.3–5 It is an oral,...

Background The identification of acutely ill patients at high risk for venous thromboembolism (VTE) may be determined clinically or by use of integer‐based scoring systems. These scores demonstrated modest performance in external data sets. Objectives To evaluate the performance of machine learning models compared to the IMPROVE score. Methods The APEX trial randomized 7513 acutely medically ill patients to extended duration betrixaban vs. enoxaparin. Including 68 variables, a super learner model (ML) was built to predict VTE by combining estimates from 5 families of candidate models. A “reduced” model (rML) was also developed using 16 variables that were thought, a priori, to be associated with VTE. The IMPROVE score was calculated for each patient. Model performance was assessed by discrimination and calibration to predict a composite VTE end point. The frequency of predicted risks of VTE were plotted and divided into tertiles. VTE risks were compared across tertiles. Results The ML and rML algorithms outperformed the IMPROVE score in predicting VTE (c‐statistic: 0.69, 0.68 and 0.59, respectively). The Hosmer‐Lemeshow goodness‐of‐fit P‐value was 0.06 for ML, 0.44 for rML, and

Non-vitamin K antagonist oral anticoagulants (NOACs) include thrombin inhibitor dabigatran and coagulation factor Xa inhibitors rivaroxaban, apixaban, edoxaban, and betrixaban. NOACs have several benefits over warfarin, including faster time to the achieve effect, rapid onset of action, fewer documented food and drug interactions, lack of need for routine INR monitoring, and improved patient satisfaction. Local hemostatic measures, supportive care, and withholding the next NOAC dose are usually sufficient to achieve hemostasis among patients presenting with minor bleeding. The administration of reversal agents should be considered in patients on NOAC's with major bleeding manifestations (life-threatening bleeding, or major uncontrolled bleeding), or those who require rapid anticoagulant reversal for an emergent surgical procedure. The Food and Drug Administration (FDA) has approved two reversal agents for NOACs: idarucizumab for dabigatran and andexanet alfa for apixaban and rivaroxaban. The American College of Cardiology (ACC), American Heart Association (AHA), and Heart Rhythm Society (HRS) have released an updated guideline for the management of patients with atrial fibrillation that provides indications for the use of these reversal agents. In addition, the final results of the ANNEXA-4 study that evaluated the efficacy and safety of andexanet alfa were recently published. Several agents are in different phases of clinical trials, and among them, ciraparantag has shown promising results. However, their higher cost and limited availability remains a concern. Here, we provide a brief review of the available reversal agents for NOACs (nonspecific and specific), recent updates on reversal strategies, lab parameters (including point-of-care tests), NOAC resumption, and agents in development.

Venous thromboembolism (VTE; includes deep venous thrombosis, DVT, and pulmonary embolism, PE) represents the third most common acute cardiovascular syndrome. Contemporary VTE management comprises primary prevention in high-risk patients, treatment of established VTE, and prevention of its recurrence (secondary prevention). Anticoagulants are the basis of VTE pharmacological prophylaxis and treatment. For several decades, parenteral (heparin and low-molecular-weight heparins, LMWHs) and oral anticoagulants (vitamin K antagonists, VKAs) have been the cornerstone of VTE prevention/treatment. The introduction of direct oral anticoagulants (DOACs: thrombin inhibitor dabigatran and Xa inhibitors rivaroxaban, apixaban, edoxaban, and betrixaban) markedly improved the management of VTE by overcoming many disadvantages of conventional anticoagulants. For primary VTE prevention in patients after total hip/knee arthroplasty, rivaroxaban, apixaban, and dabigatran are preferred over LMWHs, due to comparable efficacy and safety, but favourable acceptability (avoided everyday injections). In other high-risk populations (other surgical patients, acutely ill medical patients), LMWHs are still the recommended option. Betrixaban is currently the only DOAC approved for VTE prophylaxis in medically ill patients during and after hospitalization. For acute VTE treatment and secondary prevention, DOACs (rivaroxaban, apixaban, edoxaban, and dabigatran) are recommended as the first-line therapy in the general population. DOACs proved to be similarly effective but safer than VKAs. In some specific populations, DOACs also seem to be advantageous over conventional treatment (patients with renal impairment, elderly, long-term secondary prevention in cancer patients). Currently, there is no data from randomized head-to-head comparative studies between the DOAC classes or representatives so the choice is made mainly according to patient characteristics and pharmacokinetic properties of the drug. Venski tromboembolizam (VTE; uključuje duboku vensku trombozu, DVT i plućnu emboliju, PE) predstavlja treći najčešći akutni kardiovaskularni sindrom. Savremeno zbrinjavanje VTE uključuje primarnu prevenciju kod visokorizičnih pacijenata, lečenje uspostavljene VTE i prevenciju relapsa (sekundarna prevencija). Antikoagulansi su osnova farmakološke profilakse i lečenja VTE. Tokom nekoliko decenija su parenteralni (heparin i niskomolekularni heparini, LMWH) i oralni antikoagulansi (antagonisti vitamina K, VKA) bili kamen temeljac prevencije/lečenja VTE. Uvođenje direktnih oralnih antikoagulansa (DOAK: inhibitor trombina dabigatran i inhibitori Xa rivaroksaban, apiksaban, edoksaban i betriksaban) značajno je poboljšalo prevenciju i lečenje VTE prevazilaženjem mnogih nedostataka konvencionalnih antikoagulansa. Za primarnu prevenciju VTE kod pacijenata nakon totalne artroplastike kuka/kolena, rivaroksaban, apiksaban i dabigatran su u prednosti nad LMWH, zbog uporedive efikasnosti i bezbednosti, ali i bolje prihvatljivosti za pacijenta (izbegavanja svakodnevnih injekcija). U ostalim populacijama visokog rizika (drugi hirurški pacijenti, pacijenti sa različitim akutnim oboljenjima), LMWH su i dalje preporučena profilaksa. Betriksaban je trenutno jedini DOAK odobren za profilaksu VTE kod akutno bolesnih pacijenata tokom i nakon hospitalizacije. Za akutni tretman VTE i sekundarnu prevenciju, DOAK (rivaroksaban, apiksaban, edoksaban i dabigatran) se preporučuju kao prva linija terapije u opštoj populaciji. DOAK su se pokazali slično efikasni, ali bezbedniji od VKA. U nekim specifičnim populacijama pacijenata DOAK takođe imaju prednost u odnosu na konvencionalnu antikoagulantnu terapiju (pacijenti sa oštećenjem bubrega, starije osobe, dugotrajna sekundarna prevencija kod kancerskih pacijenata). Trenutno ne postoje podaci iz studija direktnog poređenja između klasa ili predstavnika DOAKa, tako da se izbor uglavnom vrši prema karakteristikama pacijenta i farmakokinetičkim osobinama leka.

Thromboembolic events are the leading cause of morbidity and mortality worldwide. From the second half of the 20th century, vitamin K antagonists (VKAs), warfarin and acenocoumarol, were the only anticoagulants taken orally. The major reform in anticoagulation therapy was made by the advent of direct oral anticoagulants (DOACs), about 10 years ago. Direct thrombin inhibitor (dabigatran) and direct inhibitors of factor Xa (rivaroxaban, apixaban, edoxaban, and betrixaban) have demonstrated favorable risk/benefit ratio. Compared to warfarin, DOACs are associated with a predictable pharmacokinetic profile, lower severe bleeding complications, particularly intracranial hemorrhages, and minimal drug interactions. Moreover, DOACs achieve a rapid onset of action and have shown comparable efficacy with warfarin and low molecular weight heparin (LMWH) in clinical trials. As a result, DOACs are now replacing VKAs and LMWH for many indications including stroke and systemic embolism prevention in nonvalvular atrial fibrillation, prevention, and treatment of venous thromboembolism and thromboprophylaxis following total knee/hip replacement surgery. In addition, rivaroxaban (in combination with aspirin alone or aspirin and clopidogrel) is used in the prevention of atherothrombotic events following acute coronary syndrome with elevated cardiac biomarkers. In case of severe bleeding complications under DOACs treatment, antidotes are available; idarucizumab for dabigatran reversal and andexanet alfa for rivaroxaban and apixaban. Tromboembolijski događaji predstavljaju vodeći uzrok morbiditeta i mortaliteta širom sveta. Od druge polovine 20. veka, antagonisti vitamina K (VKA), varfarin i acenokumarol bili su jedini dostupni oralni antikoagulantni lekovi. Pojava direktnih oralnih antikoagulanasa (DOAK), od pre 10-tak godina, donela je veliku promenu u antikoagulantnoj terapiji. Direktni inhibitor trombina (dabigatran) i direktni inhibitori faktora Xa (rivaroksaban, apiksaban, edoksaban i betriksaban) su pokazali povoljan odnos koristi i rizika. U poređenju sa varfarinom, DOAK pokazuju predvidljiv farmakokinetički profil, nižu incidencu ozbiljnog krvarenja posebno intrakranijalnog krvarenja i stupaju u mali broj interakcija sa drugim lekovima. Pored toga, DOAK imaju brz nastup dejstva i pokazali su komparabilnu efikasnost u poređenju sa varfarinom i niskomolekularnim heparinima (LMWH) u kliničkim ispitivanjima. Posledično, DOAK postepeno zamenjuju VKA i LMWH u mnogim indikacijama uključujući prevenciju moždanog udara i sistemskog embolizma kod pacijenata sa nevalvularnom atrijalnom fibrilacijom, prevenciju i terapiju venskog tromboembolizma, kao i tromboprofilaksu nakon ugradnje veštačkog kolena/kuka. Dodatno, rivaroksaban (sa aspirinom ili kombinacijom aspirina i klopidogrela) je indikovan u prevenciji aterotrombotičnih događaja posle akutnog koronarnog sindroma, kod pacijenata sa povećanim srčanim biomarkerima. U slučaju pojave ozbiljnog krvarenja, dostupni su antidoti; idarucizumab za dabigatran i andeksanet alfa za rivaroksaban i apiksaban.

BACKGROUND Extended-duration thromboprophylaxis with betrixaban reduces the risk of venous thromboembolism (VTE) without increasing major bleeding rates in acutely ill medical patients as compared to standard duration enoxaparin. We aimed to assess the risk-benefit of betrixaban in patients aged ≥ 80 years enrolled in the APEX trial. METHODS APEX was a randomized, double-blind trial in which patients hospitalized for acute medical illnesses received enoxaparin 40 mg qd for 10 ± 4 days or oral betrixaban 80 mg qd for 35 to 42 days. The primary efficacy outcome was VTE, the principal safety outcome was major bleeding. Net clinical benefit (NCB) was defined by the occurrence of VTE or major bleeding. RESULTS Of 7513 patients enrolled in the APEX trial, 2781 (37%) were aged ≥ 80 years. In this subgroup, VTE or major bleeding occurred in 7.0% of betrixaban patients and in 8.4% of enoxaparin patients, for a relative risk in the NCB of 0.82 (95% confidence interval 0.62-1.10). The relative risk reduction obtained with betrixaban was similar between those aged ≥ 80 years and patients younger than 80 years (5.0% and 6.7%, respectively, NCB 0.75, 0.58-0.96, P = .024), with no significant interaction across age groups (P = .33). CONCLUSIONS Event rates were higher in medically ill patients aged ≥ 80 years enrolled in the APEX study than in patients younger than 80 years. The predefined NCB was reduced with extended betrixaban therapy in both groups with no signs of age-related interactions. However, the primary efficacy endpoint was not achieved with betrixaban for patients 80 years of age or older.

Objective: To evaluate the efficacy, safety, and clinical implication of betrixaban for prophylaxis of venous thromboembolism (VTE) in patients with acute medical illness. Data Sources: A search for clinical trials was performed from January 2006 to January 2017 in English language using Clinicaltrials.gov and PubMed/MEDLINE. The following search terms were used: betrixaban, pharmacokinetics, pharmacology, and drug safety. Study Selection: The following limits were used to access the clinical trials: controlled clinical trial, randomized clinical trial, clinical trial, clinical trial phase II, and clinical trial phase III. The search was narrowed to include only humans. Data Extraction: The search criteria resulted in 6 clinical trials assessing the safety and efficacy of betrixaban. Additionally, references from publications assessing the safety and efficacy of betrixaban in atrial fibrillation, treatment and prevention of VTE, and extended duration VTE prophylaxis were assessed. Data Synthesis: Prior to 2017, no anticoagulant therapy had been approved for extended VTE prophylaxis in acutely ill medical patients. Betrixaban is the first direct oral anticoagulant approved for VTE prophylaxis in adult, acutely ill patients at risk for thromboembolisms. Based on the APEX trial, betrixaban 80 mg administered daily for 35 to 42 days was compared to enoxaparin administered daily for 6 to 14 days. In 7441 patients, fewer VTEs were seen in the betrixaban compared to enoxaparin with no significant difference in adverse reactions. Conclusion: Based on clinical trials, betrixaban appears to be safe and effective in preventing VTE in acutely ill patients who are at risk of developing VTE.

Cardiovascular diseases are the most common cause of death in the world. For almost 60 years, vitamin K antagonists (VKAs) were the mainstay of anticoagulation therapy, but in recent years direct oral anticoagulants (DOACs) have become the anticoagulant treatment of choice. DOACs were initially considered drugs with no significant food interactions; however, clinical observations from daily practice have proved otherwise as interactions with food ingredients have been reported. Food, dietary supplements or herbs may contain substances that, when administered concomitantly with DOACs, can potentially affect the plasma concentration of the drugs. The aim of this paper was to evaluate the clinical significance of drug–food interactions of DOACs, such as dabigatran, rivaroxaban, apixaban, edoxaban and betrixaban. Patients treated with anticoagulants should avoid products containing St. John’s wort and take special care with other food ingredients. As the interest in dietary supplements is on the rise, healthcare providers can contribute to the development of well-designed clinical trials on interactions between DOACs and food, and distribute sufficient knowledge about the proper use of these supplements among patients.

In 2018, the International Council for Standardization in Haematology (ICSH) published a consensus document providing guidance for laboratories on measuring direct oral anticoagulants (DOACs). Since that publication, several significant changes related to DOACs have occurred, including the approval of a new DOAC by the Food and Drug Administration, betrixaban, and a specific DOAC reversal agent intended for use when the reversal of anticoagulation with apixaban or rivaroxaban is needed due to life-threatening or uncontrolled bleeding, andexanet alfa. In addition, this ICSH Working Party recognized areas where additional information was warranted, including patient population considerations and updates in point-of-care testing. The information in this manuscript supplements our previous ICSH DOAC laboratory guidance document. The recommendations provided are based on (1) information from peer-reviewed publications about laboratory measurement of DOACs, (2) contributing author's personal experience/expert opinion and (3) good laboratory practice.

The pandemic that we are currently living through, caused by SARS COVID-19, changed the way we perceive deadly diseases along with our comprehension of efficacious drugs. In this project, we compare 57 repurposable drugs from different categories like anti-inflammatory, anticancer, anticoagulant, antiviral, anti-parasitic, antidepressant, Parkinson’s disease drugs, and discontinued drugs, to identify the best drugs with strongest binding affinities, that can be considered for treating COVID-19. We identified three target proteins- Main protease (PDB ID: 6LU7), Spike Glycoprotein with human receptor ACE2 (PDB ID: 6M0J), and RNA-dependent RNA polymerase (RdRp) in complex with Remdesivir (PDB ID: 7BV2) which are responsible for transcription, entrance into host’s cell and viral replication respectively. We used AutoDock Vina for docking, and based our results on the binding affinity and hydrogen bond interactions. We shortlisted 15 drugs- Vilazodone, Lopinavir, Ritonavir, Darunavir, Selinexor, Etoposide, Nintedanib, Methylprednisolone, Hydrocortisone, Tolcapone, Apixaban, Rivaroxaban, Dabigatran, Betrixaban, and Amprenavir- that showcased comparable or higher affinity than Remdesivir with all of our three target proteins, and recommend these for further studies.

The presented review concerns contemporary views on specific aspects of anticoagulant and thrombolytic treatment of venous thromboembolism and mostly of acute pulmonary embolism. Modern classifications of patients with acute pulmonary embolism, based on early mortality risk and severity of thromboembolic event, are reproduced. The importance of multidisciplinary approach to the management of patients with pulmonary embolism with the assistance of cardiologist, intensive care specialist, pulmonologist, thoracic and cardiovascular surgeon, aimed at the management of pulmonary embolism at all stages: from clinical suspicion to the selection and performing of any medical intervention, is emphasized. Anticoagulant treatment with the demonstration of results of major trials, devoted to efficacy and safety evaluation of anticoagulants, is highlighted in details. Moreover, characteristics, basic dosage and dosage scheme of direct (new) oral anticoagulants, including apixaban, rivaroxaban, dabigatran, edoxaban and betrixaban are described in the article. In particular, the management of patients with bleeding complications of anticoagulant treatment and its application in cancer patients, who often have venous thromboembolism, is described. Additionally, modern approaches to systemic thrombolysis with intravenous streptokinase, urokinase and tissue plasminogen activators are presented in this review. The indications, contraindications, results of clinical trials devoted to various regimens of thrombolytic therapy, including treatment of pulmonary embolism by lower doses of fibrinolytic agents, are described.

Purpose To assess concordance regarding proposed interactions between enzyme-inducing antiepileptic drugs (EI-AEDs) and direct oral anticoagulants (DOACs) in leading, international drug compendia. Methods We measured consistency of interaction reporting for each DOAC with a group of potent EI-AEDs among eight provider and consumer-focused drug compendia. Discrepant severity ranking systems were consolidated on a 0 to 4 scale. Percent agreement (PA) and Scott/Fleiss' Kappa (к) were used to quantify inter-compendia agreement on interaction listings, with linear weighting when consolidated severity rankings were taken into account (wPA and wк, respectively). Results For dabigatran, rivaroxaban, apixaban, and edoxaban, poor inter-compendia concordance was observed for interaction listings with EI-AEDs, with and without accounting for severity rankings (wPA: 0.54-0.72/wк: -0.08-0.03, and PA 0.47-0.79/к: -0.09-0.09, respectively). Conversely, betrixaban was consistently listed as not interacting with EI-AEDs in almost all assessed compendia, despite overlap in P-glycoprotein-based transport with other DOACs. Only 6/20 (30%) EI-AED/DOAC interactions were listed in all eight databases, and even in these six cases, severity rankings were universally discordant. Extreme inconsistencies in interaction reporting (some compendia assigning the highest possible severity ranking, while others reported no interactions) were observed in half of the individually examined interactions (10/20). Conclusions Drug compendia are highly inconsistent in the inclusion and reported severity of interactions between EI-AEDs and DOACs. Generation of high-quality, real-world evidence from large-scale outcome studies is imperative to resolve discordance and provide clarity for clinical guidelines.

Acutely ill medical patients with cancer are at increased risk of venous thromboembolism (VTE). Thromboprophylaxis is recommended in the presence of cancer, but its safety is not known. The aim of this study was to assess the efficacy and safety of extended prophylaxis with betrixaban in cancer patients enrolled in the APEX trial. APEX was a randomized, double-blind trial comparing oral betrixaban 80 mg qd administered for 35-42 days with subcutaneous enoxaparin 40 mg qd administered for 10 ± 4 days. Patients with acute medical illness and a history of cancer or active cancer were eligible for inclusion. Primary efficacy outcome was VTE (composite of symptomatic VTE and asymptomatic proximal deep vein thrombosis); primary safety outcome was major bleeding. Of 7513 patients enrolled in the APEX trial, 959 patients (12.8%), 499 randomized to betrixaban and 460 to enoxaparin, had cancer. The primary efficacy outcome occurred in 5.7% of cancer patients treated with betrixaban and in 6.2% treated with enoxaparin (p = 0.95). No significant interaction according to the presence or absence of cancer was observed (p = 0.36). Major bleeding events occurred in 0.8% of patients in the betrixaban group and in 0% in the enoxaparin group (p = 0.13), with no significant interaction (p = 0.07). The composite of major and clinically relevant non-major bleeds was similar between the two groups (2.9% and 2.0%, respectively, RR 1.43, 95% CI 0.63-3.27). Betrixaban was similarly effective in the reduction of VTE among subjects with and without cancer. The incidence of major bleeding was similarly low.

We review pivotal clinical trials of extended-duration venous thromboembolism (VTE) prophylaxis strategies in acute medically ill patients. For VTE prophylaxis in medically ill patients, current guidelines recommend the use of parenteral anticoagulants during hospitalization but not for extended duration prophylaxis. In 2017, betrixaban was approved for VTE prophylaxis in acute medically ill patients based on the results of the APEX trial. The MARINER trial missed its primary endpoint of reducing the composite of symptomatic VTE and VTE-related mortality with rivaroxaban compared with placebo. It did show that rivaroxaban halved the symptomatic VTE rate compared with placebo and did achieve its secondary endpoint. The EXCLAIM, ADOPT, and MAGELLAN trials did not demonstrate a net clinical benefit in reduction of VTE events due to an increase in bleeding events. The risk of VTE remains high in acute medically ill patients after hospital discharge. Based on the results of the APEX trial which showed a reduction in VTE, the FDA approved betrixaban for use in acute medically ill patients for extended duration VTE prophylaxis. Next steps are to implement the findings from APEX and MARINER into clinical practice to reduce recurrent VTE, lower healthcare cost, and reduce rehospitalization.

Anticoagulant drugs comprise a specific subcategory of antithrombotic agents that act to inhibit blood coagulation at various stages, reducing clot development and ultimately lowering the risk of developing new-onset or recurrent thrombosis. Although the long history of anticoagulant drugs has been characteristically shaped by coumarin and heparin derivatives, a new generation of direct oral anticoagulants (DOACs), which specifically inhibit thrombin or activated factor X, combine many advantages of their progenitor drugs, and hence are prepotently revolutionizing the landscape of antithrombotic therapy. Several drugs (apixaban [BMS-562247], dabigatran [BIBR953], edoxaban [DU-1766], rivaroxaban [BAY 59–7939]) have already received widespread approval by national or supranational medicinal agencies. This narrative article provides a state-of-the-art for these and for several other DOACs at different stages of clinical evaluation (betrixaban, darexaban, eribaxaban, letaxaban, nokxaban), and certain others whose development has been discontinued (AZD-0837, fidexaban, LY517717, odiparcil, otamixaban, TTP889, and ximelagatran). What clearly emerges from our analysis is that DOACs sharing very similar mechanisms of action are still characterized by different efficacy and safety profiles. This not only depends on biochemical, biological, and pharmacokinetic characteristics, but also on lack of standardization between different clinical trials in terms of targeted disease, patient recruitment, sample size, duration and endpoints, as well as lack of harmonization around procedures used for drug licensing. These factors contribute to challenging the minds of physicians, who may find difficulty navigating their way through multiple indications, different pharmacological profiles, various side effects, and specific drug-to-drug interactions. Such considerations also burden laboratory professionals, who may face organizational and economic challenges in developing and/or implementing multiple assays to assess the pharmacodynamics (effect on coagulation) or pharmacokinetics (drug levels) of DOACs.

Objectives: Venous thromboembolism (VTE) incurs substantial costs to the UK National Health Service (NHS). Betrixaban is approved in the US for VTE prophylaxis with a recommended 35–42 days of treatment. This analysis modeled the budget impact of introducing betrixaban for extended-duration VTE prophylaxis in nonsurgical patients with acute medical illness at risk of VTE in the UK, where it is not yet licensed. Methods: The 5-year budget impact of introducing betrixaban into current prophylaxis (low molecular weight heparin and fondaparinux) was estimated for the UK NHS. The Phase 3 APEX study provided primary event (VTE, myocardial infarction, ischemic stroke, and death; all-cause or VTE-related) and treatment complications data. Literature informed risk of recurrent events and long-term complications, population, market share, and costs for treatment and management of events. Network meta-analyses informed symptomatic DVT, pulmonary embolism and VTE-related death rates in fondaparinux patients. Deterministic sensitivity analyses explored uncertainty. Results: Introducing betrixaban accrued savings of £1,290,000-£23,000,000 in years 1–5. Savings were from reduced primary VTE events, which reduced recurrent events and future complications. All sensitivity analyses showed savings. Conclusion: Introducing extended-duration VTE prophylaxis with betrixaban in the UK would accrue substantial savings annually over the next 5 years compared to current prophylaxis. Clinical trial registration: www.clinicaltrials.gov identifier is NCT01583218.

Cancer accounts for 20% of all venous thromboembolism (VTE) worldwide and cancer patients are at four- to sevenfold increased risk of thrombosis compared to non-cancer patients. VTE is also a morbid complication of cancer and its incidence is rising. Thrombosis is also a second leading cause of death in cancer patients. The standard of care management for the prevention and treatment of cancer-associated thrombosis (CAT) remains the administration of low-molecular-weight heparins (LMWHs). In the last decade, five direct oral anticoagulants (DOACs), dabigatran, rivaroxaban, apixaban, edoxaban and betrixaban, have been approved for the treatment and prevention of VTE in the general patient population. In this review, we discuss the results of the already published clinical trials with DOACs in the treatment of CAT and the ongoing clinical trials with DOACs in the prevention and treatment of CAT.

While substantial evidence supports the use of standard-duration injectable anticoagulants for venous thromboembolism (VTE) prophylaxis, consensus is mixed about which agents may be preferred in acutely ill patients with ongoing need of VTE prophylaxis past the first 10-day duration of hospital stay and post-discharge. Non-vitamin K antagonist oral anticoagulants (NOACs) provide Factor Xa inhibition to prevent the thrombin generation essential in thromboembolism development, but evidence for the efficacy and safety of most NOACs is conflicting regarding extended-duration prophylaxis. Enoxaparin, a preferred injectable anticoagulant in standard-duration VTE prophylaxis, has shown an increased risk of major bleeding events when used in extended-duration prophylaxis, which outweighs its benefit. Rivaroxaban has demonstrated efficacy in extended-duration prophylaxis, but both rivaroxaban and apixaban have shown increased risks of major bleeding. Betrixaban remains the only NOAC approved in the USA for extended-duration VTE prophylaxis, and it demonstrates efficacy, with fewer adverse effects than other NOACs. This review evaluates the appropriateness of different NOAC agents compared with current therapies for the extended-duration VTE prophylaxis setting in medically ill populations.

OBJECTIVE: To evaluate current clinical evidence for the use of direct oral anticoagulants (DOACs) for extended-duration thromboprophylaxis in the acutely ill medical population for venous thromboembolism (VTE) and bleeding events. DATA SOURCES: Were obtained through a MEDLINE/PubMed search for clinical trials conducted from March 2008 to 2018 using relevant key words. Limitations of English and human subjects were applied to search results. STUDY SELECTION AND DATA EXTRACTION: Forty-one articles were identified, and abstracts reviewed by the authors for inclusion of the study population (acutely ill medical patients) and VTE outcomes. Clinical studies evaluating the use of DOACs for extended duration of VTE prevention in acutely ill medical patients were included in the review, resulting in three clinical trials and two subgroup analyses. The participants enrolled had an overall mean age of 71.4 years. DATA SYNTHESIS: The DOAC trials collectively demonstrated a positive outcome in composite endpoints of VTE prevention with extended-duration thromboprophylaxis in acutely ill medical patients compared with enoxaparin. As for safety, rivaroxaban and apixaban trials reported more major bleeding events compared with enoxaparin. The betrixaban trial demonstrated no difference in bleeding compared with enoxaparin. CONCLUSION: DOACs reduced the number of VTE events in acutely ill medical patients on extended-duration thromboprophylaxis, but with an overall increased bleeding risk. An individualized patient approach based on risk factors should be utilized for treatment with extended-duration DOAC in the older adult population with recent hospitalization.

Patients admitted with acute medical conditions are at prolonged risk for venous thrombosis. The efficacy and safety, and the appropriate duration of thromboprophylaxis have not been clearly determined. In recent years, direct coagulation factor inhibitors have been successfully tested for the prevention and treatment of arterial and venous thromboembolism. Betrixaban is a novel direct inhibitor of factor Xa with a noteworthy pharmacological feature: limited renal clearance. Areas covered: This review focuses on the pharmacological profile of Betrixaban, including its clinical efficacy and safety. It also covers the results of the pivotal APEX trial assessing the safety and efficacy of betrixaban for extended thromboprophylaxis in patients with acute medical conditions. Expert opinion: The role of extended thromboprophylaxis in acutely ill medical patients is subject to debate. The beneficial results in terms of VTE prevention were offset by the relevant increase in major bleeding. Betrixaban is the only direct oral anticoagulant to have shown a favorable risk-benefit profile in this setting especially in patients at higher risk for thrombosis.

Factor Xa (fXa) is a crucial player in various thromboembolic disorders. Inhibition of fXa can provide safe and effective antithrombotic effects. In this study, a series of anthranilamide compounds were designed by utilizing structure-based design strategies. Optimization at P1 and P4 groups led to the discovery of compound 16g: a highly potent, selective fXa inhibitor with pronounced in vitro anticoagulant activity. Moreover, 16g also displayed excellent in vivo antithrombotic activity in the rat venous thrombosis (VT) and arteriovenous shunt (AV-SHUNT) models. The bleeding risk evaluation showed that 16g had a safer profile than that of betrixaban at 1 mg/kg and 5 mg/kg dose. Additionally, 16g also exhibited satisfactory PK profiles. Eventually, 16g was selected to investigate its effect on hypoxia-reoxygenation- induced H9C2 cell viability. MTT results showed that H9C2 cell viability can be remarkably alleviated by 16g.

Direct oral anticoagulants are an alternative to anticoagulants based on vitamin K antagonists. Monitoring of direct oral anticoagulant concentration levels is necessary in specific cases (e.g. in emergency conditions, for determination of the cause of bleeding, adverse effects, risk of drug-direct oral anticoagulants interaction); therefore, a sensitive and specific method is needed. A methanol protein precipitation method followed by liquid chromatography with high-resolution mass spectrometry was developed for simultaneous separation and determination of apixaban, betrixaban, edoxaban, dabigatran, rivaroxaban and ximelagatran. The proposed method was fully validated in terms of linearity, the limits of detection and quantification, intra- and inter-day trueness and precision, recovery, matrix effect, process efficiency and stability. The method shows a strong correlation (Pearson's correlation coefficients > 0.92) with coagulation assays of apixaban, dabigatran and rivaroxaban (dilute thrombin time for gatrans and anti Xa factor (anti-Xa) activity for xabans). In addition, the developed method was applied for the identification and determination of apixaban and dabigatran in post-mortem serum samples. The developed method is a good alternative to coagulation tests which may show various interferences.

BACKGROUND AND PURPOSE P-glycoprotein (P-gp) exhibits a broad substrate specificity and affects pharmacokinetics, especially intestinal absorption. However, prediction, in vivo, of P-gp-mediated drug-drug interaction (DDI) and non-linear absorption at the preclinical stage, is challenging. Here we evaluate the use of human MDR1 mouse artificial chromosome (hMDR1-MAC) mice carrying human P-gp and lacking their own murine P-gp to quantitatively predict human P-gp-mediated DDI and non-linear absorption. EXPERIMENTAL APPROACH The P-gp substrates (aliskiren, betrixaban, celiprolol, digoxin, fexofenadine and talinolol) were administered orally to wild-type, Mdr1a/b-knockout (KO) and hMDR1-MAC mice, and their plasma concentrations were measured. We calculated the ratio of area under the curve (AUCR) in mice (AUCMdr1a/b-KO /AUCwild-type or AUCMdr1a/b-KO /AUChMDR1-MAC ) estimated as attributable to complete P-gp inhibition and the human AUCR with and without P-gp inhibitor administration. The correlations of AUCRhuman with AUCRwild-type and AUCRhMDR1-MAC were investigated. For aliskiren, betrixaban and celiprolol, the Km and Vmax values for P-gp in hMDR1-MAC mice and humans were optimized from different dosing studies using GastroPlus. The correlations of Km and Vmax for P-gp between human and hMDR1-MAC mice were investigated. KEY RESULTS A better correlation between AUCRhuman and AUCRhMDR1-MAC (R2 = 0.88) was observed. Moreover, good relationships of Km (R2 = 1.00) and Vmax (R2 = 0.98) for P-gp between humans and hMDR1-MAC mice were observed. CONCLUSIONS AND IMPLICATIONS These results suggest that P-gp-mediated DDI and non-linear absorption can be predicted using hMDR1-MAC mice. These mice are a useful in vivo tool for quantitatively predicting P-gp-mediated disposition in drug discovery and development.

The introduction of direct oral anticoagulants (DOACs), such as dabigatran, rivaroxaban, apixaban, edoxaban, and betrixaban, provides safe and effective alternative to previous anticoagulant therapies. DOACs directly, selectively, and reversibly inhibit factors IIa or Xa. The coagulation effect follows the plasma concentration–time profile of the respective anticoagulant. The short half-life of a DOAC constrains the daily oral intake. Because DOACs have predictable pharmacokinetic and pharmacodynamic responses at a fixed dose, they do not require monitoring. However in specific clinical situations and for particular patient populations, testing may be helpful for patient management. The effect of DOACs on the screening coagulation assays such as prothrombin time (PT), activated partial thromboplastin time (APTT), and thrombin time (TT) is directly linked to reagent composition, and clotting time can be different from reagent to reagent, depending on the DOAC’s reagent sensitivity. Liquid chromatography–mass spectrometry (LC-MS/MS) is considered the gold standard method for DOAC measurement, but it is time consuming and requires expensive equipment. The general consensus for the assessment of a DOAC is clotting or chromogenic assays using specific standard calibrators and controls. This review provides a short summary of DOAC properties and an update on laboratory methods for measuring DOACs.

Purpose This review describes and analyzes literature to provide recommendations for use of extended-duration thromboprophylaxis (EDT) in medically ill patients. Summary Guidelines recommend pharmacologic thromboprophylaxis for patients at increased thrombosis risk during hospitalization and recommend against extending thromboprophylaxis beyond hospitalization. Despite these recommendations, observational data demonstrate that venous thromboembolism (VTE) risk persists following hospital discharge. A MEDLINE literature search was performed to identify original research evaluating the safety and efficacy of EDT. Eight meta-analyses and 5 randomized controlled trials—each varying in the agents studied (enoxaparin, rivaroxaban, apixaban, and betrixaban)—were selected for inclusion. Collectively, the evaluated data demonstrates that EDT reduces the incidence of VTE at the expense of increasing the risk of major bleeding and without providing mortality reduction. Variations in enrollment criteria, differences in EDT strategies, and uncertainty regarding proper patient selection limit the applicability of EDT in practice. Rivaroxaban and betrixaban gained Food and Drug Administration (FDA) approval on the basis of results of the APEX and MARINER trials and a post hoc analysis of the MAGELLEN trial results. Although a number of agents are FDA approved for use in EDT, clinicians must carefully weigh the risks vs benefits of EDT with these agents until studies demonstrate a more favorable risk-benefit profile. Conclusion Evidence to support EDT in medically ill patients is inconclusive and has highlighted the need for an individualized approach. The reviewed evidence supports guideline recommendations from both the American College of Chest Physicians and the American Society of Hematology that recommend against routine use of EDT in the majority of medically ill patients. Future studies are needed to optimize the risk-benefit profile of EDT and to ensure proper patient selection.

Venous thromboembolism (VTE) is the leading preventable cause of death in hospitalized patients and data consistently show that acutely ill medical patients remain at increased risk for VTE-related morbidity and mortality in the post-hospital discharge period. Prescribing extended thromboprophylaxis for up to 45 days following an acute hospitalization in key patient subgroups that include more than one-quarter of hospitalized medically-ill patients represents a paradigm shift in the way hospital-based physicians think about VTE prevention. Advances in the field of primary thromboprophylaxis in acutely-ill medical patients using validated VTE and bleeding risk assessment models have established key patient subgroups at high risk of VTE and low risk of bleeding that may benefit from both in-hospital and extended thromboprophylaxis. The direct oral anticoagulants betrixaban and rivaroxaban are now U.S. Food and Drug Administration-approved for in-hospital and extended thromboprophylaxis in medically ill patients and provide net clinical benefit in these key subgroups. Coronavirus disease-2019 may predispose patients to VTE due to excessive inflammation, platelet activation, endothelial dysfunction, and hemostasis. The optimum preventive strategy for these patients requires further investigation. This article aims to review the latest concepts in predicting and preventing VTE and discuss the new era of extended thromboprophylaxis in hospitalized medically ill patients.

The 2019 guideline from the Anticoagulation Forum provides clear instructions on how to use 2 agents for reversing the effects of direct oral anticoagulants (DOACs): idarucizumab for dabigatran-associated bleeding and andexanet alfa for bleeding associated with rivaroxaban and apixaban. The guideline also discusses off-label use of andexanet alfa for bleeding associated with edoxaban and betrixaban and the use of hemostatic agents such as activated prothrombin complex concentrate and 4-factor prothrombin complex concentrate. Lastly, it offers approaches for building and managing stewardship programs at the health system level.

There is a laboratory and clinical need to know the impact of direct oral anticoagulants (DOACs) on diagnostic tests to avoid misinterpretation of results. Although the regulatory labelling documents provide some information about the influences of each DOAC on diagnostic tests, these are usually limited to some of the most common tests and no head to head comparison is available. In this paper, we report the impact of DOACs on several thrombophilia tests, including assessment of antithrombin, protein S and protein C activity assays, detection of activated protein C resistance and assays used for lupus anticoagulant. Results are compared and discussed with data obtained from literature. The final goal of this comprehensive review is to provide practical recommendations for laboratories to avoid misdiagnosis due to oral direct factor Xa (FXa) or IIa (FIIa) inhibitors. Overall, oral direct FXa (apixaban, betrixaban, edoxaban and rivaroxaban) and FIIa (dabigatran) antagonists may affect clot-based thrombophilia diagnostic tests resulting in false-positive or false-negative results. An effect on FIIa-based thrombophilia diagnostic tests is observed with dabigatran but not with anti-FXa DOACs and conversely for FXa-based thrombophilia diagnostic tests. No impact was observed with antigenic/chromogenic methods for the assessment of protein S and C activity. In conclusion, interpretation of thrombophilia diagnostic tests results should be done with caution in patients on DOACs. The use of a device/chemical compound able to remove or antagonize the effect of DOACs or the development of new diagnostic tests insensitive to DOACs should be considered to minimize the risk of false results.

Direct oral anticoagulants (DOACs, or non-vitamin K antagonist oral anticoagulants [NOACs]) include dabigatran, a direct thrombin inhibitor, and factor Xa inhibitors (rivaroxaban, apixaban, edoxaban, betrixaban). They have largely replaced vitamin K anticoagulants (VKAs) in clinical practice. Their overall safety profile concerning bleeding appears to be at least equivalent, if not superior, to VKAs. However, the lack of a specific reversal agent for DOACs remains an important concern. Fortunately, there were recent remarkable innovations in management of DOAC-associated bleeding with the introduction of specific antidotes, including idarucizumab for dabigatran and andexanet alfa for factor Xa inhibitors. Still in development is ciraparantag, an agent purported to act as a “universal” reversal agent. In the following chapter, we will review the reversal strategies available for DOAC-treated patients who present with life-threatening bleeding or with indication for emergent surgery. We will also review the mechanism of action and data supporting the use of specific reversal agents, nonspecific pro-hemostatic therapies including prothrombin complex concentrate, and future research avenues.

Background Anticoagulants are essential in the prevention of venous thromboembolism. However, the effectiveness and safety of different anticoagulants have always been controversial. Therefore, we aimed to expand the sample of anticoagulant results and rank the efficacy and safety of 19 anticoagulants in the prevention of venous thromboembolism when total knee or total hip arthroplasty procedure is performed. Methods A systematic review and network meta-analysis of randomized trials of adult patients undergoing total hip or knee arthroplasty were conducted. The trials were identified from PubMed, Web of Science, Cochrane Library, and Embase databases, in which anticoagulants were used as interventions randomized controlled trial. The incidence of venous embolism and bleeding are the key outcomes of assessing the efficacy of intervention drugs. We used the Physical Therapy Evidence Database (PEDro) to assess risk bias and used pairwise comparison and network meta-analysis with random effects to estimate the summary relative risk. The study has been registered with PROSPERO, number CRD42020200747. Results From the 4083 identified manuscripts, 45,067 participants from 53 randomized trials were included in the analysis and randomly assigned to 19 anticoagulants. With Enoxaparin as a control, Rivaroxaban (risk difference 0.07, 95 % credible interval 0.06 to 0.08), Edoxaban (RD 0.09, 95 % CrI 0.08 to 0.11), and Apixaban (RD 0.05, 95 % CrI 0.04 to 0.06) had the best effect in preventing VTE. However, in terms of comprehensive bleeding rate, Apixaban, Edoxaban, and Darexaban were the most effective and stable. Although effective in preventing VTE, bleeding remains relatively high in Rivaroxaban. Enoxaparin is low-molecular-weight heparin that is widely used in clinics, and although its overall efficacy is not the best, its efficacy and safety are very stable. Conclusion According to the available data, Apixaban, Edoxaban, and Darexaban are better than any anticoagulants in the prevention of VTE and bleeding during total knee or total hip arthroplasty. In our study, Fondaparinux, Eribaxaban, Dalteparin, Betrixaban, Bemiparin, Reviparin, Acenocoumarol, and Tinzaparin were scarce in the included studies, therefore, more evidence is needed to prove their efficacy and safety.

Dabigatran, rivaroxaban, apixaban, edoxaban, and betrixaban are direct oral anticoagulants (DOACs). Their inter-individual variability in pharmacodynamics and pharmacokinetics (transport and metabolism) is high, and could result from genetic polymorphisms. As recommended by the French Network of Pharmacogenetics (RNPGx), the management of some treatments in cardiovascular diseases (as antiplatelet agents, oral vitamin K antagonists, and statins) can rely on genetic testing in order to improve healthcare by reducing therapeutic resistance or toxicity. This paper is a review of association studies between single nucleotide polymorphisms (SNPs) and systemic exposure variation of DOACs. Most of the results presented here have a lot to do with some SNPs of CES1 (rs2244613, rs8192935, and rs71647871) and ABCB1 (rs1128503, rs2032582, rs1045642, and rs4148738) genes, and dabigatran, rivaroxaban, and apixaban. Regarding edoxaban and betrixaban, as well as SNPs in the CYP3A4 and CYP3A5 genes, literature is scarce, and further studies are needed.

COVID-19 is also manifested with hypercoagulability, pulmonary intravascular coagulation, microangiopathy, and venous thromboembolism (VTE) or arterial thrombosis. Predisposing risk factors to severe COVID-19 are male sex, underlying cardiovascular disease, or cardiovascular risk factors including noncontrolled diabetes mellitus or arterial hypertension, obesity, and advanced age. The VAS-European Independent Foundation in Angiology/Vascular Medicine draws attention to patients with vascular disease (VD) and presents an integral strategy for the management of patients with VD or cardiovascular risk factors (VD-CVR) and COVID-19. VAS recommends (1) a COVID-19-oriented primary health care network for patients with VD-CVR for identification of patients with VD-CVR in the community and patients' education for disease symptoms, use of eHealth technology, adherence to the antithrombotic and vascular regulating treatments, and (2) close medical follow-up for efficacious control of VD progression and prompt application of physical and social distancing measures in case of new epidemic waves. For patients with VD-CVR who receive home treatment for COVID-19, VAS recommends assessment for (1) disease worsening risk and prioritized hospitalization of those at high risk and (2) VTE risk assessment and thromboprophylaxis with rivaroxaban, betrixaban, or low-molecular-weight heparin (LMWH) for those at high risk. For hospitalized patients with VD-CVR and COVID-19, VAS recommends (1) routine thromboprophylaxis with weight-adjusted intermediate doses of LMWH (unless contraindication); (2) LMWH as the drug of choice over unfractionated heparin or direct oral anticoagulants for the treatment of VTE or hypercoagulability; (3) careful evaluation of the risk for disease worsening and prompt application of targeted antiviral or convalescence treatments; (4) monitoring of D-dimer for optimization of the antithrombotic treatment; and (5) evaluation of the risk of VTE before hospital discharge using the IMPROVE-D-dimer score and prolonged post-discharge thromboprophylaxis with rivaroxaban, betrixaban, or LMWH.

Degradation of betrixaban, an oral anticoagulant recently approved by the U.S. Food and Drug Administration (FDA), and its N-nitrosodimethylamine (NDMA) formation potential were studied mechanistically in the presence of monochloramine (NH2Cl), free chlorine, and ozone. Upon monochloramination, the formation of NDMA exceeded 1% at basic pH and was significant at circumneutral pH as well. The kinetic studies revealed that the reaction between betrixaban and monochloramine followed pseudo-first-order reaction kinetics. Increasing monochloramine concentration, its reaction time, and pH all significantly enhanced the NDMA formation yield, which also increased three-fold in the presence of bromide during monochloraminantion. The presence of nitrite inhibited the formation of NDMA under the same conditions. This study revealed a new potent and significant precursor of NDMA, indicating that monochloramination of waters containing betrixaban can lead to the formation of NDMA and other disinfection by-products such as dichloroacetonitrile (DCAN) and dimethylformamide (DMF). Moreover, chlorination of betrixaban by hypochlorite also yielded NDMA, albeit at two orders of magnitude lower yield than chloramination, while no NDMA formation was observed from ozonation of betrixaban.

Background Hospitalized acutely ill medical patients are at risk for fatal and major thromboembolic events. Whether use of extended-duration primary thromboprophylaxis can prevent such events is unknown. Objectives The purpose of this study was to evaluate whether extended-duration rivaroxaban reduces the risk of venous and arterial fatal and major thromboembolic events without significantly increasing major bleeding in acutely ill medical patients after discharge. Methods MARINER (A Study of Rivaroxaban [JNJ-39039039] on the Venous Thromboembolic Risk in Post-Hospital Discharge Patients) studied acutely ill medical patients with additional risk factors for venous thromboembolism (VTE). Medically ill patients with a baseline creatinine clearance ≥50 ml/min were randomized in a double-blind fashion to rivaroxaban 10 mg or placebo daily at hospital discharge for 45 days. Exploratory efficacy analyses were performed with the intent-to-treat population including all data through day 45. Time-to-event curves were calculated using the Kaplan-Meier method. A blinded independent committee adjudicated all clinical events. Results In total, 4,909 patients were assigned to rivaroxaban and 4,913 patients to placebo. The mean age was 67.8 years, 55.5% were men, mean baseline creatinine clearance was 87.8 ml/min, and mean duration of hospitalization was 6.7 days. The pre-specified composite efficacy endpoint (symptomatic VTE, myocardial infarction, nonhemorrhagic stroke, and cardiovascular death) occurred in 1.28% and 1.77% of patients in the rivaroxaban and placebo groups, respectively (hazard ratio: 0.72; 95% confidence interval: 0.52 to 1.00; p = 0.049), whereas major bleeding occurred in 0.27% and 0.18% of patients in the rivaroxaban and placebo groups, respectively (hazard ratio: 1.44; 95% confidence interval: 0.62 to 3.37; p = 0.398). Conclusions Extended-duration rivaroxaban in hospitalized medically ill patients resulted in a 28% reduction in fatal and major thromboembolic events without a significant increase in major bleeding. (A Study of Rivaroxaban [JNJ-39039039] on the Venous Thromboembolic Risk in Post-Hospital Discharge Patients [MARINER]; NCT02111564), Central Illustration

Extended thromboprophylaxis given to medically ill patients for up to 45 days following an acute hospitalization remains an emerging topic among many hospital-based health care providers. Recent advancements in the field of extended thromboprophylaxis using risk stratification and careful patient selection criteria have led to an improved safety profile of direct oral anticoagulants (DOACs) and established net clinical benefit when given to key patient subgroups at high risk of venous thromboembolism (VTE) and low risk of bleeding. The Food and Drug Administration (FDA) has now approved the DOACs betrixaban and rivaroxaban for both in-hospital and extended thromboprophylaxis in medically ill patients in these key subgroups, which represents more than one-quarter of hospitalized medically ill patients. This has potential to significantly reduce VTE-related morbidity and mortality for these patients. Emerging data also supports reductions in the risk of arterial thromboembolism in medically ill patients with extended thromboprophylaxis post-hospital discharge using DOACs. This article aims to review the most recent concepts of predicting and preventing VTE and to discuss emerging paradigms of extended thromboprophylaxis in hospitalized medically ill patients utilizing an individualized, risk-adapted approach.

Introduction Directs oral anticoagulants (DOACs) can interfere with coagulation assays, especially in thrombophilia workup. To avoid these interferences, a new device, DOAC Filter, allows the removal of DOACs from citrated plasma. This study aims to confirm that DOAC Filter efficiently removes DOACs and to ascertain that coagulation assays are not impacted by filtration. Methods Directs oral anticoagulants Filter (Diagnostica Stago, France) is a filtration cartridge in which DOAC molecules are trapped by noncovalent binding, while plasma is filtered through a solid phase. Normal pool plasma (NPP) spiked with DOACs up to 300 ng/mL, with dabigatran etexilate (n = 27), rivaroxaban (n = 35), apixaban (n = 33), and edoxaban (n = 27) or 120 ng/mL for betrixaban (n = 4), and 18 plasma's samples from DOAC-treated patients were used to assess efficacy. The potential impact of DOAC Filter on coagulation assays was evaluated with NPP and plasma's samples from positive and negative lupus anticoagulant (LA) patients. Results Directs oral anticoagulants concentrations measured after filtration were below the limit of detection (LoD) of DOAC-specific assays for all plasmas tested, except for one apixaban plasma sample, with postfiltration concentration slightly higher than anti-Xa assay LoD (25.1 ng/mL). Coagulation assays results varied between -4 and +8% after filtration and between -6 and +8% for LA plasmas. Such limited variations are not expected to have any clinical impact. Conclusion Directs oral anticoagulants Filter efficiently removes DOACs from plasma and achieves concentrations below DOAC-specific assays LoD, except in the case of one apixaban sample. The integrity of plasma is respected, and the cartridge seems not to impact LA diagnosis.

Summary Currently licenced direct oral anticoagulants selectively target thrombin (eg, dabigatran) or coagulation factor Xa (eg, apixaban, betrixaban, edoxaban, and rivaroxaban). Designed to be given in fixed doses without routine monitoring, direct oral anticoagulants have a lower propensity for food and drug interactions than do vitamin K antagonists, and in randomised controlled trials involving around 250 000 patients, they were at least as effective for prevention and treatment of thrombosis and were associated with a lower risk of life-threatening bleeding. The absolute benefits of direct oral anticoagulants over vitamin K antagonists are modest; however, guidelines recommend them in preference to vitamin K antagonists for most indications because of their ease of use and superior safety. The greatest benefits of direct oral anticoagulants are likely to be in patients who were previously deemed unsuitable for vitamin K antagonist therapy. The emergence of generic preparations is expected to further increase the uptake of direct oral anticoagulants, particularly in countries where they are currently not widely used because of cost. Direct oral anticoagulants are contraindicated in patients with mechanical heart valves and should be used with caution or avoided in patients with advanced kidney or liver disease. In this Therapeutics paper, we review the pharmacology of direct oral anticoagulants, summarise the evidence that led to their approval and incorporation into treatment guidelines, and explore key unresolved issues. We also briefly discuss future perspectives for the development of oral anticoagulants.

Venous thromboembolism (VTE) is a common and preventable cause of morbidity and mortality in hospitalized patients. Low-molecular-weight heparin, low-dose unfractionated heparin, fondaparinux, and warfarin have been the mainstay options for the prevention and treatment of VTE before the emergence of nonvitamin K antagonist oral anticoagulants (NOACs) such as dabigatran, rivaroxaban, apixaban, and edoxaban. Despite the advantages of NOACs in improving patient adherence, none of them are approved for the prevention of VTE in acutely ill medical patients at high risk of thromboembolism. Betrixaban is a new NOAC and a factor Xa inhibitor that was approved for extended-duration thromboprophylaxis in these high-risk patients. The approval was based on the results of the APEX (Acute Medically Ill VTE Prevention with Extended Duration Betrixaban) study. In this Phase III randomized controlled trial, once-daily oral betrixaban (35 to 42 days extended duration) was associated with a reduction of composite VTE with no difference in major bleeding when compared to once-daily subcutaneous enoxaparin (6 to 14 days standard duration). Betrixaban differs from other NOACs by having a longer half-life, minimal CYP450 interactions, and minimal renal clearance. This article provides an overview of betrixaban's pharmacological profile, clinical trial results, and potential roles in therapy.

Despite significant advances in strategies and compliance with venous thromboembolism (VTE) prophylaxis, hospital-acquired VTE remains a leading cause of preventable deaths in acute medically ill patients. A majority of venous thromboembolic events occur posthospital discharge when risk factors persist and pharmacoprophylactic regimens have been completed. Until recently, there has been an unmet need for safe and effective extended-duration VTE prevention. Three major trials evaluated this concept, but excess bleeding outweighed the benefit of reduced thromboembolic events. Betrixaban is an oral direct factor Xa inhibitor recently approved for extended-duration VTE prophylaxis in acute medically ill patients at risk for thromboembolism based on results from the Phase III APEX study. This article reviews the pharmacology and supporting data for betrixaban.