Edoxaban: an update on the new oral direct factor Xa inhibitor

Being precise with anticoagulation to reduce adverse drug reactions: are we there yet?

Anticoagulants are potent therapeutics widely used in medical and surgical settings, and the amount spent on anticoagulation is rising. Although warfarin remains a widely prescribed oral anticoagulant, prescriptions of direct oral anticoagulants (DOACs) have increased rapidly. Heparin-based parenteral anticoagulants include both unfractionated and low molecular weight heparins (LMWHs). In clinical practice, anticoagulants are generally well tolerated, although interindividual variability in response is apparent. This variability in anticoagulant response can lead to serious incident thrombosis, haemorrhage and off-target adverse reactions such as heparin-induced thrombocytopaenia (HIT). This review seeks to highlight the genetic, environmental and clinical factors associated with variability in anticoagulant response, and review the current evidence base for tailoring the drug, dose, and/or monitoring decisions to identified patient subgroups to improve anticoagulant safety. Areas that would benefit from further research are also identified. Validated variants in VKORC1, CYP2C9 and CYP4F2 constitute biomarkers for differential warfarin response and genotype-informed warfarin dosing has been shown to reduce adverse clinical events. Polymorphisms in CES1 appear relevant to dabigatran exposure but the genetic studies focusing on clinical outcomes such as bleeding are sparse. The influence of body weight on LMWH response merits further attention, as does the relationship between anti-Xa levels and clinical outcomes. Ultimately, safe and effective anticoagulation requires both a deeper parsing of factors contributing to variable response, and further prospective studies to determine optimal therapeutic strategies in identified higher risk subgroups.

Pharmacokinetics and pharmacodynamics of direct oral anticoagulants

INTRODUCTION

Direct oral anticoagulants (DOACs) have overtaken vitamin K antagonists to become the most widely used method of anticoagulation for most indications. Their stable and predictable pharmacokinetics combined with relatively simple dosing, and the absence of routine monitoring has made them an attractive proposition for healthcare providers. Despite the benefits of DOACs as a class, important differences exist between individual DOAC drugs in respect of their pharmacokinetic and pharmacodynamic profiles with implications for dosing and reversal in cases of major bleeding.

AREAS COVERED

This review summarizes the state of knowledge relating to the pharmacokinetics of dabigatran (factor IIa/thrombin inhibitor) and apixaban, edoxaban and rivaroxaban (factor Xa) inhibitors. We focus on pharmacokinetic differences between the drugs which may have clinically significant implications.

EXPERT OPINION

Patient-centered care necessitates a careful consideration of the pharmacokinetic and pharmacodynamic differences between DOACs, and how these relate to individual patient circumstances. Prescribers should be aware of the potential for pharmacokinetic drug interactions with DOACs which may influence prescribing decisions in patients with multiple comorbidities. In order to give an appropriate dose of DOAC drugs, accurate estimation of renal function using the Cockcroft-Gault formula using actual body weight is necessary. An increasing body of evidence supports the use of DOACs in patients who are obese, and this is becoming more routine in clinical practice.

Re-bleeding and all-cause mortality risk in non-variceal upper gastrointestinal bleeding: focusing on patients receiving oral anticoagulant therapy

OBJECTIVE

Non-variceal upper gastrointestinal bleeding (NVUGIB) in patients receiving oral anticoagulants (OACs) may be fatal; however, little is known about re-bleeding and all-cause mortality after successful hemostasis. We investigated the clinical characteristics and risk factors for re-bleeding and death after successful hemostasis.

METHODS

Patients receiving OACs and diagnosed with NVUGIB between 2007 and 2021 were enrolled. All NVUGIB incidents were confirmed if definite bleeding in the upper gastrointestinal tract was detected via esophagogastroduodenoscopy.

RESULTS

A total of 132 patients receiving OACs were diagnosed with NVUGIB. Males were the majority (72, 54.5%), and bleeding was detected mostly in the stomach (99, 75%) and was most often due to peptic ulcers (PU) (88, 66.7%). After successful hemostasis of index NVUGIB, 40 patients (30.3%) experienced re-bleeding. Among them, 15 (37.5%) died, and among those, 3 (2.3%) were related to re-bleeding. Multivariate analysis revealed that duodenal bleeding (odds ratio [OR]: 3.305; 95% confidence interval [CI]: 1.152-9.479, p = 0.026) and Charlson comorbidity index score (CCI) (OR: 1.22; 95% CI: 1.052-1.419, p = 0.009) were significant risk factors for re-bleeding. Index albumin levels (OR: 0.134; 95% CI: 0.035-0.506, p = 0.003), previous PU or upper gastrointestinal bleeding (UGIB) history (OR: 4.626; 95% CI: 1.375-15.567, p = 0.013), and CCI (OR: 1.293; 95% CI: 1.058-1.581, p = 0.012) were related all-cause mortality.

CONCLUSION

CCI and duodenal bleeding are risk factors for re-bleeding in patients with NVUGIB who were receiving OACs, while low index albumin levels and previous PU and UGIB history are associated with all-cause mortality.

Dilemmas in the Choice of Adequate Therapeutic Treatment in Patients with Acute Pulmonary Embolism—From Modern Recommendations to Clinical Application

Pulmonary thromboembolism is a very common cardiovascular disease, with a high mortality rate. Despite the clear guidelines, this disease still represents a great challenge both in diagnosis and treatment. The heterogeneous clinical picture, often without pathognomonic signs and symptoms, represents a huge differential diagnostic problem even for experienced doctors. The decisions surrounding this therapeutic regimen also represent a major dilemma in the group of patients who are hemodynamically stable at initial presentation and have signs of right ventricular (RV) dysfunction proven by echocardiography and positive biomarker values (pulmonary embolism of intermediate–high risk). Studies have shown conflicting results about the benefit of using fibrinolytic therapy in this group of patients until hemodynamic decompensation, due to the risk of major bleeding. The latest recommendations give preference to new oral anticoagulants (NOACs) compared to vitamin K antagonists (VKA), except for certain categories of patients (patients with antiphospholipid syndrome, mechanical valves, pregnancy). When using oral anticoagulant therapy, special attention should be paid to drug–drug interactions, which can lead to many complications, even to the death of the patient. Special population groups such as pregnant women, obese patients, patients with antiphospholipid syndrome and the incidence of cancer represent a great therapeutic challenge in the application of anticoagulant therapy. In these patients, not only must the effectiveness of the drugs be taken into account, but great attention must be paid to their safety and possible side effects, which is why a multidisciplinary approach is emphasized in order to provide the best therapeutic option.

Improved absorption of itraconazole tablet by co-administration with lemon beverages in a lung transplant recipient: A case report

After lung transplantation, itraconazole (ITCZ) is used as a prophylaxis for aspergillosis. ITCZ is a weak base with high lipophilicity, and the dissolution and absorption of ITCZ tablets and capsules are pH dependent. Therefore, ITCZ may not achieve sufficient serum concentrations in patients with higher gastric pH because of its poor bioavailability. We report a case of a woman in fifties with post-COVID-19 respiratory failure who successfully underwent lung transplantation, followed by improved bioavailability of ITCZ tablets when given with acidic lemon beverages. The patient was initially administered ITCZ oral solution; this was discontinued because of its unpleasant taste, nausea, and vomiting. The ITCZ oral solution was replaced with ITCZ tablets 78 days after transplantation; however, serum concentrations of ITCZ and hydroxy-ITCZ were below the detection limit (100 ng/mL). We co-administered ITCZ tablets with commercially available lemon beverages. Subsequently, serum concentrations of ITCZ and hydroxy-ITCZ increased to 341 and 673 ng/mL, respectively, on the 125th day after transplantation. Infection with fungi, including Aspergillus spp., was not observed in this case. The patient had no adverse events such as gastric ulcer or hyperglycemia. These results suggest that the co-administration of lemon beverages and ITCZ tablets may help achieve better absorption of ITCZ in patients taking acid suppressants.

The value and limitations of new oral anticoagulant plasma level assessments

The class of new oral anticoagulants (NOACs) has been developed to provide reliable oral anticoagulation without the need for therapeutic drug monitoring. Based on phase I and II trials and pharmacokinetic and pharmacodynamic modeling, fixed drug doses have been selected for large phase III clinical trials for each currently available NOAC. In these trials, the use of the fixed dose without plasma level assessments was shown to be at least as effective and at least as safe as vitamin K antagonists with continuous therapeutic drug monitoring. Real world evidence reaffirms that the use of a fixed NOAC dose without plasma level assessment is safe and effective in a large variety of patients. Nevertheless, measurement of NOAC plasma levels can add information that may be useful in some clinical scenarios. This review discusses the possible use cases, the limitations, and the practical implementation of measuring NOAC plasma concentrations.

Balloon-Assisted Thrombectomy and Intrasinus Urokinase Thrombolysis for Severe Cerebral Venous Sinus Thrombosis

Background: Current clinical guidelines recommend systemic anticoagulation as the initial treatment for severe cerebral venous sinus thrombosis (CVST). However, anticoagulation alone does not always dissolve large and extensive CVSTs in some patients. Here, we investigated the effectiveness and safety of balloon-assisted thrombectomy and intrasinus urokinase thrombolysis in our retrospective study of a series of 23 patients with CVST. Methods: We reviewed the clinical, radiological, and outcome data of all patients. Complete recanalization was defined as all the occluded sinuses were recanalized on digital subtraction angiography or Contrast-enhanced magnetic resonance venography. Partial recanalization was defined as the complete recanalization of one sinus but persistent occlusion of other sinuses, or partial recanalization of one or more sinuses. The modified Rankin Scale (mRS) was used to represent the clinical outcome. Results: From May 2017 to November 2019, a total of 23 patients were treated with balloon-assisted thrombectomy and intrasinus urokinase thrombolysis. A total of 84 venous sinuses were involved, ≥3 sinuses were involved in 20 (87%) patients. Among them, 21 (91%) patients achieved technical success. Complete and partial recanalization were obtained in 17 (81%) and 4 (19%) patients at 6 months follow-up, respectively. All 21 patients had mRS scores of 0 (18) or 1 (3). Conclusions: Our case series shows that balloon-assisted thrombectomy combined with intrasinus urokinase thrombolysis and activated partial thromboplastin time-regulated systemic anticoagulation is safe and effective in treating severe CVST.

Therapeutic Effectiveness and Safety of Repurposing Drugs for the Treatment of COVID-19: Position Standing in 2021

COVID-19, transmitted by SARS-CoV-2, is one of the most serious pandemic situations in the history of mankind, and has already infected a huge population across the globe. This horrendously contagious viral outbreak was first identified in China and within a very short time it affected the world's health, transport, economic, and academic sectors. Despite the recent approval of a few anti-COVID-19 vaccines, their unavailability and insufficiency along with the lack of other potential therapeutic options are continuing to worsen the situation, with valuable lives continuing to be lost. In this situation, researchers across the globe are focusing on repurposing prospective drugs and prophylaxis such as favipiravir, remdesivir, chloroquine, hydroxychloroquine, ivermectin, lopinavir-ritonavir, azithromycin, doxycycline, ACEIs/ARBs, rivaroxaban, and protease inhibitors, which were preliminarily based on in vitro and in vivo pharmacological and toxicological study reports followed by clinical applications. Based on available preliminary data derived from limited clinical trials, the US National Institute of Health (NIH) and USFDA also recommended a few drugs to be repurposed i.e., hydroxychloroquine, remdesivir, and favipiravir. However, World Health Organization later recommended against the use of chloroquine, hydroxychloroquine, remdesivir, and lopinavir/ritonavir in the treatment of COVID-19 infections. Combining basic knowledge of viral pathogenesis and pharmacodynamics of drug molecules as well as in silico approaches, many drug candidates have been investigated in clinical trials, some of which have been proven to be partially effective against COVID-19, and many of the other drugs are currently under extensive screening. The repurposing of prospective drug candidates from different stages of evaluation can be a handy wellspring in COVID-19 management and treatment along with approved anti-COVID-19 vaccines. This review article combined the information from completed clinical trials, case series, cohort studies, meta-analyses, and retrospective studies to focus on the current status of repurposing drugs in 2021.

Direct Oral Anticoagulants: From Randomized Clinical Trials to Real-World Clinical Practice

Direct oral anticoagulants (DOACs) are a more manageable alternative than vitamin K antagonists (VKAs) to prevent stroke in patients with nonvalvular atrial fibrillation and to prevent and treat venous thromboembolism. Despite their widespread use in clinical practice, there are still some unresolved issues on optimizing their use in particular clinical settings. Herein, we reviewed the current clinical evidence on uses of DOACs from pharmacology and clinical indications to safety and practical issues such as drugs and food interactions. Dabigatran is the DOAC most affected by interactions with drugs and food, although all DOACs demonstrate a favorable pharmacokinetic profile. Management issues associated with perioperative procedures, bleeding treatment, and special populations (pregnancy, renal and hepatic impairment, elderly, and oncologic patients) have been discussed. Literature evidence shows that DOACs are at least as effective as VKAs, with a favorable safety profile; data are particularly encouraging in using low doses of edoxaban in elderly patients, and edoxaban and rivaroxaban in the treatment of venous thromboembolism in oncologic patients. In the next year, DOAC clinical indications are likely to be further extended.

Using Pharmacogenetics of Direct Oral Anticoagulants to Predict Changes in Their Pharmacokinetics and the Risk of Adverse Drug Reactions

Dabigatran, rivaroxaban, apixaban, and edoxaban are direct oral anticoagulants (DOACs) that are increasingly used worldwide. Taking into account their widespread use for the prevention of thromboembolism in cardiology, neurology, orthopedics, and coronavirus disease 2019 (COVID 19) as well as their different pharmacokinetics and pharmacogenetics dependence, it is critical to explore new opportunities for DOACs administration and predict their dosage when used as monotherapy or in combination with other drugs. In this review, we describe the details of the relative pharmacogenetics on the pharmacokinetics of DOACs as well as new data concerning the clinical characteristics that predetermine the needed dosage and the risk of adverse drug reactions (ADRs). The usefulness of genetic information before and shortly after the initiation of DOACs is also discussed. The reasons for particular attention to these issues are not only new genetic knowledge and genotyping possibilities, but also the risk of serious ADRs (primarily, gastrointestinal bleeding). Taking into account the effect of the carriership of single nucleotide variants (SNVs) of genes encoding biotransformation enzymes and DOACs metabolism, the use of these measures is important to predict changes in pharmacokinetics and the risk of ADRs in patients with a high risk of thromboembolism who receive anticoagulant therapy.

Safety and effectiveness of edoxaban in Japanese patients with nonvalvular atrial fibrillation: Final report of a two-year postmarketing surveillance study (ETNA-AF-Japan)

BACKGROUND

Direct oral anticoagulants (DOACs) are the recommended first-line therapy for ischemic stroke prevention in patients with nonvalvular atrial fibrillation (NVAF). However, the safety and effectiveness of edoxaban for this indication requires monitoring over the long term in real-world settings.

METHODS

ETNA-AF-Japan (trial no. UMIN000017011) was a prospective, multicenter observational study (part of postmarketing surveillance in Japan). NVAF patients due to receive edoxaban to prevent ischemic stroke were enrolled between 13 April 2015 and 30 September 2017.

RESULTS

A total of 11 569 patients were enrolled. For the 11 111 patients (female, 40.6%) whose data comprised the safety analysis set, age, body weight, creatinine clearance (CLcr), and CHADS2 score were 74.2 ± 10.0 years, 60.0 ± 12.7 kg, 63.9 ± 25.8 mL/min, and 2.2 ± 1.3, respectively (mean ± SD). The majority (86.3%) received edoxaban in accordance with package insert information. The mean duration of treatment was 561.9 ± 261.2 days. The annual incidence (95% confidence interval) of all bleeding events and major bleeding events was 5.60% (5.25%-5.98%) and 1.02% (0.88%-1.18%), respectively. The annual incidence of ischemic stroke (excluding transient ischemic attack, TIA) or systemic embolism was 1.08% (0.93%-1.25%). Multivariate analysis showed low body weight, low CLcr, history of gastrointestinal bleeding, anemia, and use of an antiplatelet agent to be associated with major bleeding, and history of ischemic stroke or TIA, vascular disease, and antiplatelet agent use to be associated with ischemic stroke (excluding TIA) or systemic embolism.

CONCLUSIONS

These results provide real-world evidence for the long-term good safety and effectiveness profile of edoxaban in Japanese NVAF patients under clinical practice.

Direct oral anticoagulants (DOACs) and neck of femur fractures: Standardising the perioperative management and time to surgery

Demographic projections for hip fragility fractures indicate a rising annual incidence by virtue of a multimorbid, ageing population with more noncommunicable diseases (NCDs). NCDs are characterised by slow progression and long duration ranging from ischaemic cardiovascular disease, cerebrovascular disease, diabetes, chronic obstructive pulmonary disease to various cancers. Management of this disease burden often involves commencing patients on oral anticoagulants to reduce the risk of thromboembolic events. The use of direct oral anticoagulants (DOACs) in clinical practice has increased due to their rapid onset of action, short half-life and predictable anticoagulant effects, without the need for routine monitoring. Safe and timely surgical intervention relies on reversal of anticoagulants. However, the lack of specific evidence-based guidelines for the perioperative management of patients on DOACs with hip fractures has proved challenging; in particular, the accessibility of DOAC-specific assays, justification of the cost-benefit ratio of targeted reversal agents and indications for neuraxial anaesthesia. This has led to potentially avoidable delays in surgical intervention. Following a literature review of the pharmacokinetic and pharmacodynamics of commonly used DOACs in our region including the role of surrogate markers, we propose a systematic, evidence-based guideline to the perioperative management of hip fractures DOACs. We believe this standardised protocol can be easily replicated between hospitals. We recommend that if patients are deemed suitable for a general anaesthesia, with satisfactory renal function, optimal surgical time should be 24 h following the last ingested dose of DOAC.

Prospective Observational Study of Safety of Early Treatment with Edoxaban in Patients with Ischemic Stroke and Atrial Fibrillation (SATES Study)

New direct oral anticoagulants are recommended for stroke prevention in patients with non-valvular atrial fibrillation (NVAF). However, no data are available regarding the optimal time to start oral anticoagulation after acute stroke. The aim of our study was to evaluate the occurrence of symptomatic bleedings within 90 days from acute cardioembolic stroke in patients who received early treatment with Edoxaban. The study was conducted according to an observational prospective uncontrolled design. Secondary endpoints were the incidence of major bleeding (MB), hemorrhagic transformation within the first week of Edoxaban treatment, minor bleeding, and recurrent stroke. We included patients with Alberta Stroke Program Early Computed Tomography Score (ASPECTS) ≥ 6, NVAF, no previous treatment with any other anticoagulant, preserved swallowing function. Patients with estimated Glomerular Filtration Rate < 50 mL/min, body weight < 60 kg, receiving cyclosporine, dronedarone, erythromycin, ketoconazole, or previous treatment with any other anticoagulant were excluded. We enrolled 75 elderly patients with moderate disability. We did not observe any symptomatic intracranial bleeding or recurrent stroke after 3 months of treatment with early administration of Edoxaban, while two gastrointestinal MB, and 11 minor bleedings were reported. Asymptomatic bleeding was evaluated with a brain Magnetic Resonance Imaging performed 5 days after starting anticoagulant treatment with Edoxaban. Specifically, we observed small petechiae in 12% of the patients, confluent petechiae in 6.6% of the patients, and small hematoma of the infarcted area in 2.7% of the patients. No intralesional hematoma or hemorrhagic lesion outside the infarcted area were observed. According to our data, the early use of Edoxaban seems to be safe in patients after cardioembolic stroke. However, due to the small size of the study sample, and the short follow-up period, further studies are needed.

Potential Therapeutic Roles for Direct Factor Xa Inhibitors in Coronavirus Infections

Human factor Xa (FXa) is a serine protease of the common coagulation pathway. FXa is known to activate prothrombin to thrombin, which eventually leads to the formation of cross-linked blood clots. While this process is important in maintaining hemostasis, excessive thrombin generation results in a host of thrombotic conditions. FXa has also been linked to inflammation via protease-activated receptors. Together, coagulopathy and inflammation have been implicated in the pathogenesis of viral infections, including the current coronavirus pandemic. Direct FXa inhibitors have been shown to possess anti-inflammatory and antiviral effects, in addition to their established anticoagulant activity. This review summarizes the pharmacological activities of direct FXa inhibitors, their pharmacokinetics, potential drug–drug interactions and adverse effects, and the details of clinical trials involving direct FXa inhibitors in coronavirus disease 2019 (COVID-19) patients.

Safety of Deep Brain Stimulation Lead Placement on Patients Requiring Anticlotting Therapies

BACKGROUND

Limited studies exist to support the safety of performing neuromodulation surgeries in patients whose anticlotting medication has been held. Here, we assess the safety of performing deep brain stimulation (DBS) in this patient population.

METHODS

All consecutive DBS patients who underwent lead and battery placement/revision at our institution between 2011 and 2020 were included in this Institutional Review Board-approved prospective outcomes database. We retrospectively recorded adverse events occurring within 90 days of surgery.

RESULTS

The study included 226 patients who underwent 381 lead placements in 267 surgeries. Of the 267 surgeries included in this study, 176 (66%) were performed on patients not on anticoagulants and 89 (33%) cases were on patients on 1 drug. Two (0.7%) cases involved a patient taking 2 drugs. A total of 49 adverse events were seen. Thirteen occurred in patients taking anticoagulants. There was no difference in adverse event rate between patients on anticlotting medication and those not (χ² [1] = 1.523, P = 0.2171). No clot-related sequelae occurred in any patient. Three hemorrhages occurred, all in patients not on anticoagulants.

CONCLUSIONS

We found no increased risk of complications in patients routinely on anticlotting medication undergoing DBS lead placement. We show that our protocol was successful in balancing increased risks of bleeding and of thromboembolic events in this patient group.

Effects of concomitant use of prasugrel with edoxaban on bleeding time, pharmacodynamics, and pharmacokinetics of edoxaban in healthy elderly Japanese male subjects: a clinical pharmacology study

Background

Dual therapy with a direct oral anticoagulant (DOAC) plus a P2Y₁₂ receptor inhibitor is recommended in patients with nonvalvular atrial fibrillation who undergo percutaneous coronary intervention. Thus, we evaluated the effects of DOAC edoxaban plus P2Y₁₂ receptor inhibitor prasugrel on bleeding time (BT), and pharmacodynamics (PD) and pharmacokinetics (PK) of edoxaban in healthy elderly Japanese male subjects.

Methods

A single-center, clinical pharmacology study with randomized, open-label, repeated dosing enrolled 24 participants in two groups of 12 receiving 30 mg edoxaban once daily for 3 days; then 30 mg edoxaban plus 2.5 mg prasugrel (Group 1) or 30 mg edoxaban plus 3.75 mg prasugrel (Group 2) once daily for 5 days. Primary endpoint was BT by the Ivy method. Secondary endpoints were the PD parameters of prothrombin time (PT), activated partial thromboplastin time (aPTT), prothrombin fragment F1 + 2 (F1 + 2), and P2Y₁₂ reaction units (PRU), and PK profiles of edoxaban alone and in combination with prasugrel.

Results

Geometric least squares mean of BT ratios (vs. baseline) for 3-day edoxaban treatment were 1.097 (90% confidence interval (CI) 0.911-1.321) in Group 1 and 1.327 (90% CI 1.035-1.703) in Group 2; for 5-day edoxaban plus 2.5 mg and 3.75 mg prasugrel, they were 1.581 (90% CI 1.197-2.087) and 1.996 (90% CI 1.482-2.690), respectively. Contributions of prasugrel to the effects (edoxaban + prasugrel/edoxaban) were 1.442 (90% CI 1.096-1.897) in Group 1 and 1.504 (90% CI 1.172-1.930) in Group 2. Edoxaban prolonged PT and aPTT and decreased F1 + 2. Adding on prasugrel did not appreciably change PT, aPTT, or F1 + 2. Prasugrel reduced PRU, whereas edoxaban had no effect on PRU. We recorded 26 adverse events; 23 were treatment-emergent (positive fecal occult blood test). All participants with adverse events recovered during follow-up.

Conclusions

Coadministration of 2.5 mg and 3.75 mg prasugrel with 30 mg edoxaban prolonged BT in healthy elderly Japanese male subjects. The effect was dependent on the dose of prasugrel. Prasugrel did not affect PD or PK profiles of edoxaban. Edoxaban had no effect on PD of prasugrel.

Trial registration

Japan Registry of Clinical Trials No. jRCTs071190006; registration date, 26-April-2019.

Guidance on Short-Term Management of Atrial Fibrillation in Coronavirus Disease 2019

Atrial fibrillation is a common clinical manifestation in hospitalized patients with coronavirus disease 2019 (COVID‐19). Medications used to treat atrial fibrillation, such as antiarrhythmic drugs and anticoagulants, may have significant drug interactions with emerging COVID‐19 treatments. Common unintended nontherapeutic target effects of COVID‐19 treatment include potassium channel blockade, cytochrome P 450 isoenzyme inhibition or activation, and P‐glycoprotein inhibition. Drug‐drug interactions with antiarrhythmic drugs and anticoagulants in these patients may lead to significant bradycardia, ventricular arrhythmias, or severe bleeding. It is important for clinicians to be aware of these interactions, drug metabolism changes, and clinical consequences when choosing antiarrhythmic drugs and anticoagulants for COVID‐19 patients with atrial fibrillation. The objective of this review is to provide a practical guide for clinicians who are managing COVID‐19 patients with concomitant atrial fibrillation.

Postmarketing surveillance on the clinical use of edoxaban in patients with nonvalvular atrial fibrillation (ETNA-AF-Japan): One-year safety and effectiveness analyses

BACKGROUND

The safety and effectiveness of edoxaban in real-world clinical settings have not yet been elucidated thoroughly among Japanese patients with nonvalvular atrial fibrillation (NVAF). We report the one-year interim results of ETNA-AF-Japan (Edoxaban Treatment in routiNe clinical prActice in patients with nonvalvular Atrial Fibrillation: UMIN000017011), an ongoing two-year study.

METHODS

ETNA-AF-Japan is a prospective, real-world multicenter observational study that analyzes the long-term safety and effectiveness of edoxaban. Physicians recorded clinical characteristics, bleeding events, and clinical events of ischemic stroke and systemic embolism, among others.

RESULTS

In total, 11 569 patients with NVAF were enrolled. The demographic and clinical characteristics of the patients in the safety analysis set (n = 11 107) were a mean age of 74.2 ± 10.0 years; female sex, 40.6%; age ≥75 years, 52.4%; body weight ≤60 kg, 54.3%; creatinine clearance ≤50 mL/min, 31.2%; mean CHADS2 score of 2.2 ± 1.3. The mean treatment period was 311.2 days (median; 366.0 days), and ~80% of patients continued edoxaban treatment. In the safety analysis, the incidence of all bleeding events was 6.32% [95% CI: 5.87, 6.79] (n = 702), and for major bleeding, it was 1.08% [0.90, 1.29] (n = 120). In the effectiveness analysis set (n = 11 059), the incidence of ischemic stroke (excluding TIA) or systemic embolism was 1.10% [0.92, 1.32] (n = 122).

CONCLUSIONS

At one-year follow-up, the results showed no major concerns about the safety and effectiveness of edoxaban in Japanese patients with NVAF in a real-world clinical setting.

Effects of Rivaroxaban on Platelet Aggregation

Rivaroxaban is a direct oral anti-factor Xa anticoagulant. It has recently been suggested that rivaroxaban may affect platelet function in vitro; however, little is known about the clinical impact of this likely antiplatelet effect and whether this probable phenomenon is dose-dependent. Our aim was to determine whether rivaroxaban at 4 different doses inhibits direct platelet aggregation. We included adult patients of both sexes and who were allocated to one of the following groups depending on the prescribed daily dose of rivaroxaban: 5, 10, 15, and 20 mg. In 80 patients (20 patients/group), the percentage of platelet aggregation was determined by means of platelet aggregometry tests before and after rivaroxaban use. Basal samples were obtained before starting rivaroxaban and 1 month after treatment, both 2 and 24 hours after the last dose of the drug (12 hours after in the case of rivaroxaban 5 mg). We used 5 platelet agonists: adenosine diphosphate, epinephrine, arachidonic acid, collagen, and thrombin. There were no significant changes in the percentage of platelet aggregation before and after rivaroxaban use independently of the dose administered and the agonist used. Our results have clearly shown that rivaroxaban, even at a high dose, does not directly affect platelet aggregation.

Safety and Effectiveness of Edoxaban in Japanese Venous Thromboembolism Patients - Final Analysis of One-Year Follow-up Data From a Japanese Postmarketing Observational Study (ETNA-VTE-Japan)

Background: ETNA-VTE-Japan is a prospective, observational study conducted as part of a postmarketing study regarding the safety and effectiveness of edoxaban in Japanese patients with venous thromboembolism (VTE). The results of the final analysis of data collected at 1 year are presented. Methods and Results: A total of 1,732 patients were included in this study. The safety and effectiveness were evaluated in 1,702 patients (safety analysis set; SAS) and in 1,698 patients (effectiveness analysis set). In the SAS, 39.4% of patients were aged ≥75 years, 58.2% had body weight ≤60 kg, and 22.2% had creatinine clearance <50 mL/min. Approximately 90% of patients received a dose recommended on the package insert. A total of 46.1% of patients continued treatment for 1 year, with mean and median treatment periods of 235.8 and 263.0 days, respectively. The incidence of bleeding adverse events (AE) was 10.3%; major bleeding, 2.6%; and VTE recurrence, 1.8%. The risk factor commonly associated with bleeding AE and VTE recurrence was cancer. The safety and effectiveness profiles of edoxaban in patients receiving the appropriate low dose (30 mg/day), generally used in patients with high bleeding risk, were similar to those for the appropriate standard dose (60 mg/day). Conclusions: At 1 year of treatment, there were no major concerns regarding the safety and effectiveness of edoxaban in Japanese patients with VTE.

Safety and Effectiveness of Edoxaban in Japanese Patients With Venous Thromboembolism - An Interim Analysis of Data From a Japanese Postmarketing Observational Study (ETNA-VTE-Japan)

BACKGROUND

ETNA-VTE-Japan is an ongoing prospective observational study conducted as part of a postmarketing observational study to investigate the safety and effectiveness of edoxaban in Japanese patients for whom the drug has been newly prescribed to treat venous thromboembolism (VTE) and prevent VTE recurrence. The results of an interim analysis of data collected at 3 months are presented.Methods and Results:A total of 1,732 patients were enrolled. The safety and effectiveness analyses included data from 1,703 and 1,699 patients, respectively. In the safety analysis set, 39.4% of patients were aged ≥75 years, 58.2% had body weight ≤60 kg, and 22.2% had creatinine clearance <50 mL/min. Approximately 90% of patients received a dose in accordance with the package insert. Approximately 80% of patients continued treatment; the mean treatment period was 74.5 days. The incidence of bleeding adverse events and major bleeding was 6.3% and 1.4%, respectively. The incidence of VTE recurrence and symptomatic VTE recurrence in the on-treatment population was 0.8% and 0.4%, respectively. Safety and effectiveness profiles of edoxaban in patients receiving the low dose (30 mg/day), generally administered to patients with high bleeding risk, were similar to those of the standard dose (60 mg/day).

CONCLUSIONS

The results confirm no major concerns about the safety and effectiveness of edoxaban in Japanese patients with VTE in the first 3 months of treatment. (Trial registration No.: UMIN000016387.).

Postmarketing surveillance on clinical use of edoxaban in patients with nonvalvular atrial fibrillation (ETNA-AF-Japan): Three-month interim analysis results

BACKGROUND

Direct oral anticoagulants are the first-line drugs for anticoagulation therapy in nonvalvular atrial fibrillation (NVAF). However, a real-world, large-scale, clinical study on edoxaban has not been performed. Our ongoing postmarketing surveillance, ETNA-AF-Japan (Edoxaban Treatment in routiNe clinical prActice in patients with non-valvular Atrial Fibrillation; UMIN000017011), was designed to collect such data.

METHODS

Enrollment started on 13 April 2015 and ended on 30 September 2017. Eligible patients were those diagnosed with NVAF who were to receive edoxaban for the first time and provided written consent for study participation. Baseline patient characteristics and adverse events (AEs) were collected.

RESULTS

A total of 11 569 patients were enrolled. Data for 8157 patients in the first 3 months were analyzed. Mean age, body weight, creatinine clearance (CLcr), and CHADS 2 score were 74.2 ± 10.0 years, 60.0 ± 12.6 kg, 64.0 ± 25.6 mL/min, and 2.2 ± 1.3, respectively. Female patients, and patients with age ≥75 years, body weight ≤60 kg, and CLcr <30 mL/min constituted 40.7%, 52.4%, 54.6%, and 4.7%, respectively. Patients with paroxysmal, persistent, and permanent AF constituted 46.1%, 38.7%, and 15.1%, respectively. Most patients (85.3%) received dosages according to the prescribing information, and 90.8% continued the medication for 3 months. Bleeding AEs occurred in 3.29%, including major bleeding in 0.29%.

CONCLUSIONS

The majority (90.8%) of patients continued medication and no significant safety concerns related to edoxaban were reported during the first 3 months of treatment. Clearer safety and efficacy profiles of edoxaban await data analyses after the 2-year follow-up period.

Batroxobin in combination with anticoagulation may promote venous sinus recanalization in cerebral venous thrombosis: A real-world experience

Aims

The objective of this study was to evaluate cerebral venous recanalization with magnetic resonance black‐blood thrombus imaging (MRBTI) in patients with cerebral venous thrombosis (CVT) who underwent batroxobin treatment in combination with anticoagulation.

Methods

A total of 31 CVT patients were enrolled in this real‐world registry study. The patients were divided into batroxobin (n = 21) and control groups (n = 10). In addition to the same standard anticoagulation as in the control group, patients in the batroxobin group underwent intravenous batroxobin for a total of three times.

Results

In the batroxobin group compared with the control group, we found better odds of recanalization degree [adjusted OR (95%CI) of 8.10 (1.61‐40.7)] and segment‐stenosis attenuation [adjusted OR (95%CI) of 4.48 (1.69‐11.9)] with batroxobin treatment. We further noted a higher ratio of patients with the attenuation of stenosis [adjusted OR (95%CI) of 26.4 (1.10‐635)]; as well as a higher ratio of segments with stenosis reversion [adjusted OR (95%CI) of 4.52 (1.48‐13.8)]. However, neurological deficits between the two groups showed no statistical difference at 90‐day follow‐up (P > 0.05).

Conclusions

Batroxobin may promote venous sinus recanalization and attenuate CVT‐induced stenosis. Further randomized study of this promising drug may be warranted to better delineate the amount of benefit.

Cost-effectiveness of edoxaban compared to warfarin for the treatment and secondary prevention of venous thromboembolism in the UK

Background: Venous thromboembolism (VTE), which includes pulmonary embolism (PE) and deep vein thrombosis (DVT), is the third most common acute cardiovascular disease and represents an important burden for patients and payers. Objective: The aim was to estimate the cost-effectiveness of edoxaban, a non-VKA oral anticoagulant vs. warfarin, the currently most prescribed treatment for VTE in the UK. Study design: A Markov model was built using data from the Hokusai-VTE randomised controlled trial to estimate the lifetime costs and quality-adjusted life years (QALYs) in patients with VTE treated with edoxaban or warfarin over a lifetime horizon, from the UK National Health Services perspective. The model included VTE recurrences, VTE-related complications (post-thrombotic syndrome and chronic thromboembolic pulmonary hypertension), and several types of bleeds associated with anticoagulation treatment. Patients were treated during a period of 6 months after the first VTE event, followed by flexible treatment duration (from 6 months to lifetime) after recurrence, i.e., tertiary prevention. Results: Edoxaban was found dominant vs. warfarin with 0.033 additional QALY and £55 less costs. The reduction of patient management costs, specifically monitoring costs, outweighed the higher drug costs. Edoxaban was dominant in all subgroups (index DVT only, all PE cases (PE with or without DVT), PE without DVT and PE with DVT). Cost-savings ranged from £54 to £81 while additional QALYs ranged from 0.031 to 0.046. Edoxaban was found dominant in 88.6% of cases and cost-effective in additional 10.9% of cases considering a £20,000 threshold in the probabilistic sensitivity analysis. Conclusion: Edoxaban may improve patients' quality of life in a lifetime horizon without additional costs for the healthcare system due to lower bleeding risk and no monitoring cost compared to warfarin.

Atrial fibrillation in dialysis patients: is there a place for non-vitamin K antagonist oral anticoagulants?

Atrial fibrillation (AF) occurs approximately in 3% of general population, with greater prevalence in elderly. Non-vitamin K-dependent oral anticoagulant agents (NOACs) according to the current European guidelines are recommended for patients with AF at high risk for stroke as a first-choice treatment. NOACs are not inferior to warfarin or some of them are better than warfarin in reducing the rate of ischemic stroke. Moreover, they significantly reduce the rate of intracranial hemorrhages, major bleedings, and mortality compared with warfarin. Nevertheless according to ESC guidelines, NOACs are not recommended in patients with creatinine clearance < 30 mL/min. Observational studies provide contradictive data. Only few new trials are ongoing. Therefore, it is not clear if NOACs should be in the future prescribed to patients with advanced CKD and those on dialysis. Moreover, the risk of stroke and bleeding is much higher in such population than in patients without end-stage renal disease (ESRD). The authors provide data on pros and cons of use of NOACs in ESRD patients with AF.

Pharmacogenetics of novel oral anticoagulants: a review of identified gene variants & future perspectives

Novel oral anticoagulants (NOACs) are becoming a therapy of choice in everyday clinical practice after almost 50 years during which warfarin and related coumarin derivatives were used as the main anticoagulants. Advantages of NOACs over standard anticoagulants include their predictable pharmacodynamics and pharmacokinetics, stable plasma concentrations and less drug-drug and food-drug interactions. However, pharmacogenetics has its place in administration of NOACs, as considerable interindividual variations have been detected. In this review, previous findings in pharmacogenetics of dabigatran, rivaroxaban, apixaban and edoxaban are summarized, along with recommendations for studying genes encoding metabolically important enzymes for four selected NOACs. Future directions include identification of clinically relevant SNPs, and change in optimum dosage for patients who are carriers of significant variants.

New Anticoagulants for the Prevention and Treatment of Venous Thromboembolism

Anticoagulant drugs, like vitamin K antagonists and heparin, have been the mainstay for the treatment and prevention of venous thromboembolic disease for many years. Although effective if appropriately used, traditional anticoagulants have several limitations such as unpredictable pharmacologic and pharmacokinetic responses and various adverse effects including serious bleeding complications. New oral anticoagulants have recently emerged as an alternative because of their rapid onset/offset of action, predictable linear dose-response relationships and fewer drug interactions. However, they are still associated with problems such as bleeding, lack of reversal agents and standard laboratory monitoring. In an attempt to overcome these drawbacks, key steps of the hemostatic pathway are investigated as targets for anticoagulation. Here we reviewed the traditional and new anticoagulants with respect to their targets in the coagulation cascade, along with their therapeutic advantages and disadvantages. In addition, investigational anticoagulant drugs currently in the development stages were introduced.

The genetic basis of antiplatelet and anticoagulant therapy: A pharmacogenetic review of newer antiplatelets (clopidogrel, prasugrel and ticagrelor) and anticoagulants (dabigatran, rivaroxaban, apixaban and edoxaban)

INTRODUCTION

The study of pharmacogenomics presents the possibility of individualised optimisation of drug therapy tailored to each patients' unique physiological traits. Both antiplatelet and anticoagulant drugs play a key role in the management of cardiovascular disease. Despite their importance, there is a substantial volume of literature to suggest marked person-to-person variability in their effect. Areas covered: This article reviews the data available for the genetic cause for this inter-patient variability of antiplatelet and anticoagulant drugs. The genetic basis for traditional antiplatelets (i.e. aspirin) is compared with the newly available antiplatelet medicines (clopidogrel, prasugrel and ticagrelor). Similarly, the pharmacogenetics of warfarin is compared with the newer direct oral anticoagulants (DOACs) in detail. Expert Opinion: We identify strengths and weaknesses in the research thus far; including shortcomings in trial design and a review of newer analytical techniques. The direction of this research and its real-world implications are discussed.

Reversal of direct oral anticoagulants

An understanding of how to counteract the anticoagulant effect of direct oral anticoagulants is essential in the event of haemorrhage, emergency surgery and overdose. This review summarizes strategies for the reversal of direct oral anticoagulants, including the use of novel agents.

Clinical Stroke prevention in atrial fibrillation

Oral anticoagulation therapy has reduced the risk of ischaemic stroke and improved the outcomes for patients with atrial fibrillation considerably. The emergence of the non-vitamin K oral anticoagulants as alternatives to vitamin K antagonists has significantly changed the practice of stroke prevention in atrial fibrillation. As the main complication with antithrombotic therapy is bleeding, physicians should always balance the risk of ischaemic stroke against intracranial haemorrhage and intervene where appropriate to reduce both risks. Individual approach is often mandatory due to heterogeneity of the risks and patient preferences. The purpose of this review is to summarise the current knowledge of the oral anticoagulation therapy in atrial fibrillation patients and guide physicians with the management of anticoagulants based on data from clinical trials and systematic reviews.

Edoxaban in Atrial Fibrillation and Venous Thromboembolism-Ten Key Questions and Answers: A Practical Guide

Edoxaban is the fourth non-vitamin K antagonist oral anticoagulant now available for clinical use in the prevention of stroke/systemic embolism in atrial fibrillation (AF) and in the treatment of venous thromboembolism (VTE), after the completion of large-scale randomized comparative clinical trials with the vitamin K antagonist warfarin. Edoxaban has some peculiar pharmacological properties and outcome data. Here a group of experts in AF and VTE answers a set of questions on its practical use, trying to define the profile of patients that would be most appropriate for its use.

Old and new oral anticoagulants: Food, herbal medicines and drug interactions

The most commonly prescribed oral anticoagulants worldwide are the vitamin K antagonists (VKAs) such as warfarin. Factors affecting the pharmacokinetics of VKAs are important because deviations from their narrow therapeutic window can result in bleedings due to over-anticoagulation or thrombosis because of under-anticoagulation. In addition to pharmacodynamic interactions (e.g., augmented bleeding risk for concomitant use of NSAIDs), interactions with drugs, foods, herbs, and over-the-counter medications may affect the risk/benefit ratio of VKAs. Direct oral anticoagulants (DOACs) including Factor Xa inhibitors (rivaroxaban, apixaban and edoxaban) and thrombin inhibitor (dabigatran) are poised to replace warfarin. Phase-3 studies and real-world evaluations have established that the safety profile of DOACs is superior to those of VKAs. However, some pharmacokinetic and pharmacodynamic interactions are expected. Herein we present a critical review of VKAs and DOACs with focus on their potential for interactions with drugs, foods, herbs and over-the-counter medications.

Cerebrovascular Disease: Consequences of Obesity-Induced Endothelial Dysfunction

Despite the well-known global impact of overweight and obesity in the incidence of cerebrovascular disease, many aspects of this association are still inconsistently defined. In this chapter we aim to present a critical review on the links between obesity and both ischemic and hemorrhagic stroke and discuss its influence on functional outcomes, survival, and current treatments to acute and chronic stroke. The role of cerebrovascular endothelial function and respective modulation is also described as well as its laboratory and clinical assessment. In this context, the major contributing mechanisms underlying obesity-induced cerebral endothelial function (adipokine secretion, insulin resistance, inflammation, and hypertension) are discussed. A special emphasis is given to the participation of adipokines in the pathophysiology of stroke, namely adiponectin, leptin, resistin, apelin, and visfatin.

Non-Vitamin K Antagonist Oral Anticoagulants: The Clinician's New Challenge

Millions of US patients are prescribed oral anticoagulants. Traditionally, oral anticoagulation was achieved with vitamin K antagonists (VKAs). In recent years, non-VKA oral anticoagulants (NOACs) have emerged that provide an effective and convenient alternative to VKAs. These agents possess very different pharmacologic properties from what the medical community has grown accustom to with the VKAs. Thus, a new knowledge base is required for NOACs. One particular challenge with the NOACs is the lack of specific reversal agent, resulting in difficulties correcting the coagulopathy induced by these drugs when needed. A review of the current literature is presented to assist clinicians in gaining knowledge of the NOACs to care for patients.

New Oral Anticoagulants in Nonvalvular Atrial Fibrillation

The choice of an oral anticoagulant (OAC) for patients with nonvalvular atrial fibrillation (NVAF) is a major and complex clinical decision taking into account the individual risk-benefit ratio and bearing in mind the chronicity of therapy. This review focuses on the safety and efficacy of new oral anticoagulants (NOACs) compared with conventional vitamin K antagonists (VKA) in patients with NVAF. Current data suggest that NOACs are at least as effective and safe as VKAs for most NVAF subjects. The NOACs do not mandate dietary restrictions and regular pharmacodynamic monitoring, and they seem to have lesser incidence of intracranial or fatal bleeding when compared with VKAs. However, both dabigatran 150 twice daily and rivaroxaban have a slightly higher incidence of gastrointestinal bleeding when compared with VKAs. The article will delineate the current knowledge as well as scientific gaps related to the choice and dosage of anticoagulation regimens for various NVAF subsets and will address certain common clinical scenarios requiring special considerations. The article also addresses the shortcomings of NOACs: lack of therapeutic pharmacokinetic and pharmacodynamic targets, absence of tools to assess compliance and efficacy, rigid and limited dosage options, and absence of effective and inexpensive reversal agents.

New Oral Anticoagulants and Their Reversal Agents

OPINION STATEMENT

Direct oral anticoagulants (DOAC) are an attractive therapeutic option for anticoagulant treatment in the setting of venous thromboembolism or non-valvular atrial fibrillation. These drugs overall appear to have a lower risk of life-threatening hemorrhage than the vitamin K antagonists. In addition, they demonstrate more predictable and stable pharmacokinetics. Measurement of the degree of anticoagulation is desirable in patients with DOAC-associated hemorrhage, but commonly available coagulation assays show poor sensitivity for degree of DOAC effect. DOAC-specific tests are time consuming and not widely available. All coagulation tests should be interpreted considering the timing of last intake and renal function. When life-threatening bleeding occurs, hemostasis should be restored as rapidly as possible. Non-specific prohemostatic drugs may have a role in DOAC reversal, and specific antidotes are at different stages of development. In this review, we provide a summary of DOAC characteristics and an overview of the different therapeutic options available for DOAC reversal.

Edoxaban: A Review in Deep Vein Thrombosis and Pulmonary Embolism

Edoxaban (Lixiana, Savaysa) is an oral, direct factor Xa inhibitor which has recently been approved for use in the treatment of deep vein thrombosis (DVT) and pulmonary embolism (PE) [collectively, venous thromboembolism (VTE)] and for the prevention of recurrent VTE. This article reviews the pharmacological properties of edoxaban as well as its tolerability and therapeutic efficacy in the treatment and prevention of recurrent VTE events. As demonstrated in the pivotal Hokusai-VTE phase III trial, once-daily edoxaban after initial treatment with heparin was non-inferior to standard therapy with heparin/warfarin in preventing recurrent VTE events and was associated with a significantly lower risk of clinically relevant bleeding than the traditional therapy. Edoxaban shares the advantages of other direct oral anticoagulants (DOACs) over traditional therapies, including the lack of requirement for routine coagulation monitoring, a rapid onset and offset of action, and few drug-drug interactions. It offers the convenience of once-daily dosing, can be taken without regard to food and allows for a dose reduction in patients with certain clinical features, such as moderate renal impairment or low body weight. In conclusion, edoxaban represents an effective and potentially safer alternative to traditional vitamin K antagonist therapy for the treatment and prevention of recurrent VTE. Its recent approval expands the range of DOAC agents for recurrent VTE, further facilitating treatment individualization.