Effect of edoxaban on markers of coagulation in venous and shed blood compared with fondaparinux

Risk Factors for Anemia Exacerbation Requiring Red Blood Cell Transfusion During Edoxaban Thromboprophylaxis After Orthopedic Surgery

Background An increased risk of anemia during edoxaban thromboprophylaxis in orthopedic surgery has been reported. However, the risk factors for the exacerbation of anemia requiring transfusion with irradiated red blood cell concentrates during postoperative edoxaban thromboprophylaxis remain unknown. Therefore, this study investigated the factors that increase the possibility of transfusion during edoxaban thromboprophylaxis after orthopedic surgery by reanalyzing clinical data from a previous collection. Methods A total of 221 patients who underwent total hip or knee arthroplasty at a single center between July 2011 and June 2012 were included in this study. Among these, 167 patients who received 30 mg of postoperative edoxaban thromboprophylaxis were retrospectively analyzed to identify critical factors for transfusion during edoxaban thromboprophylaxis after orthopedic surgery. Results Lower preoperative hemoglobin levels and higher intraoperative blood loss per body weight were significantly associated with an increase in the frequency of transfusion during postoperative edoxaban thromboprophylaxis. These factors were also potentially related to increased coagulation parameters during edoxaban thromboprophylaxis. Conclusion Our study shows that lower preoperative hemoglobin levels and higher intraoperative blood loss are associated with increased coagulation parameters with edoxaban thromboprophylaxis after orthopedic surgery and may lead to worsening of anemia, thereby requiring blood transfusion.

The importance of renal function in anemic patients treated with edoxaban after orthopedic surgery in a real-world clinical setting: A retrospective study

Edoxaban (Edx) has been approved to prevent venous thromboembolism after total knee and/or hip arthroplasty in Japan. However, the risk of anemia with Edx treatment remains elusive. No risk factors for Edx-associated anemia after orthopedic surgery have been reported. This study aimed to clarify the risk of anemia associated with Edx treatment and determine the risk factors for Edx-associated anemia after orthopedic surgery with a high risk for bleeding. First, the association between Edx treatment and the incidence of anemia-related events was retrospectively investigated by pharmacovigilance analyses using data from 5769,866 reports between the first quarters of 2016 and 2020 in the Food and Drug Administration Adverse Event Reporting System and 2752,050 reports between the fourth quarters of 2011 and 2019 in the Japanese Adverse Drug Event Report. Second, 221 patients who underwent Edx treatment after total knee and/or hip arthroplasty between July 2011 and June 2012 at a single center were included in a case-control study to clarify the risk factors for anemia. Edx treatment was associated with an increased risk of anemia-related events in orthopedic patients. Reduced renal function was identified as a critical risk factor for Edx-associated anemia after orthopedic surgery. The present study indicates that renal function should be considered in the risk management of increased Edx-associated anemia after orthopedic surgery.

D-dimer levels in patients with nonvalvular atrial fibrillation and acute heart failure treated with edoxaban

BACKGROUND

D-dimer levels can predict ischemic stroke in patients with acute heart failure (AHF). However, the effects of direct oral anticoagulants on D-dimer levels have not been investigated during admission for AHF in patients with atrial fibrillation (AF). This study examined D-dimer levels immediately after admission and following edoxaban initiation as a sub-analysis of a multi-center study that investigated the pharmacokinetics and pharmacodynamics of edoxaban in patients with nonvalvular AF (NVAF) and AHF.

METHODS

Hospitalized patients with NVAF and AHF received edoxaban according to the label. The primary measure was the change in D-dimer levels on 7 consecutive days after admission for AHF. We also investigated differences according to prior edoxaban use (de novo at the time of admission or continuation).

RESULTS

In 10/13 (76.9%) de novo patients, D-dimer levels exceeded the reference value (1.0 µg/mL) at admission (mean, 2.12 µg/mL) and subsequently decreased in 9 patients (at final blood sampling: mean, 1.12 µg/mL); 1 patient did not fall below the reference value due to stasis dermatitis. In the continuation group, most patients had D-dimer levels below the reference value from Day 1 (mean, 0.93 µg/mL), and levels remained stable or decreased (at final blood sampling: mean, 0.49 µg/mL). No events of stroke were observed.

CONCLUSIONS

D-dimer levels may be elevated in patients with NVAF and AHF, particularly in those without prior anticoagulant treatment. Edoxaban may be effective for lowering and keeping D-dimer levels, a biomarker for predicting ischemic stroke, below the reference value in patients with NVAF and AHF.

Comparisons of Edoxaban Versus Warfarin on Levels of Plasma Prothrombin Fragment in Patients With Nonvalvular Atrial Fibrillation

The effect of edoxaban on plasma prothrombin fragment 1+2 (PTF1+2), a sensitive maker of in vivo thrombin generation, has not been fully investigated in nonvalvular atrial fibrillation (NVAF). We compared plasma PTF1+2 levels between 25 NVAF patients receiving warfarin and 100 NVAF patients receiving edoxaban and additionally analyzed the association between plasma PTF1+2 levels and the dose of edoxaban. Plasma PTF1+2 levels were significantly higher in patients receiving edoxaban than in those receiving warfarin (141.5 ± 50.0 pmol/l vs 93.1 ± 55.7 pmol/l, p < 0.001). The prevalence of plasma PF1+2 levels above the upper limit (229 pmol/l) of the normal range did not differ between the 2 groups (4% vs 4%), whereas the prevalence of plasma PTF1+2 levels below the lower limit (69 pmol/l) of the normal range was significantly lower in patients receiving edoxaban than in those receiving warfarin (1% vs 48%, p < 0.001). Multiple linear regression analysis identified age and warfarin treatment as independent variables associated with the plasma PTF1+2 level. In a subgroup analysis, plasma PTF1+2 levels were significantly higher in 58 receiving edoxaban of 30 mg/day than in 42 receiving edoxaban of 60 mg/day (157.6 ± 50.8 pmol/l vs 121.6 ± 39.8 pmol/l, p = 0.01); however, after adjusting for confounding factors, the dose of edoxaban was not independently associated with the plasma PTF1+2 level. In conclusion, edoxaban sufficiently inhibits thrombin generation unrelated to its dose in NVAF, although its inhibitory effect is weaker compared with warfarin.

Perioperative management of patients with atrial fibrillation receiving anticoagulant therapy

The number of patients with atrial fibrillation (AF) and the number of patients indicated for anticoagulant therapy have been increasing because AF would affect patient survival due to thromboembolism. Once AF develops, following the disappearance of pulsation, the circumstances within the atrium become prothrombotic and thrombus formation within the left atrium occurs in patients with AF. In recent years, not only warfarin but also new oral anticoagulants were introduced clinically and have become used as oral anticoagulants. In the perioperative period, the risk of major hemorrhage needs to be reduced. On the other hand, the suspension of anticoagulant therapy and neutralization of anticoagulant effects elevate the risk of thrombosis. The perioperative management of patients receiving anticoagulant therapy is different from that of scheduled surgery and emergency surgery. In addition, knowledge of the characteristics of each oral anticoagulant is required at drug cessation and resumption. Unlike warfarin, which has been used in the past five decades, direct oral anticoagulants (DOACs) do not have sensitive indicators such as prothrombin time-international normalized ratio. To avoid major hemorrhages and thromboembolism, quantitative assays can be implemented for DOAC monitoring and for reversal therapies in perioperative settings.

The clinical impact of edoxaban for the patients with postoperative anemia after total hip arthroplasty

BACKGROUND

Postoperative anemia is a common complication after total hip arthroplasty (THA). However, the effect of edoxaban on postoperative anemia after THA remains unclear. Here, we retrospectively evaluated the clinical assessment of postoperative anemia and the associated changes of coagulation parameters in patients undergoing thromboprophylaxis with edoxaban compared with fondaparinux as a conventional anticoagulant thromboprophylactic agent after THA.

METHODS

One hundred and forty-nine patients who underwent THA from July 2010 to June 2012 were divided into two groups, according to whether they were operated on before or after the approval of edoxaban: the fondaparinux group (Group F: 86 patients) and the edoxaban group (Group E: 63 patients). The frequency of postoperative anemia and blood coagulation values were investigated.

RESULTS

Postoperative anemia developed more frequently in Group E than in Group F after surgery. However, the degree of postoperative anemia showed no significant difference between the groups. Meanwhile, prothrombin time (PT), prothrombin time-international normalized ratio (PT-INR), and activated partial thromboplastin time were markedly higher in patients with edoxaban-associated postoperative anemia, which showed an increased potential to predict the occurrence of postoperative anemia. Additionally, both PT and PT-INR in Group E were also correlated with the volume of estimated blood loss.

CONCLUSION

The frequency of postoperative anemia was increased in patients treated with edoxaban, compared to fondaparinux, after THA. Edoxaban thromboprophylaxis might, therefore, require more careful monitoring to prevent postoperative anemia. Additionally, particular prolongation of PT and PT-INR induced by edoxaban treatment might predict postoperative anemia.

Efficacy and safety of edoxaban for treatment of portal vein thrombosis following danaparoid sodium in patients with liver cirrhosis

AIM

To compare the efficacy and safety of edoxaban and warfarin for treatment of portal vein thrombosis (PVT) following danaparoid sodium in patients with liver cirrhosis.

METHODS

Fifty cirrhotic patients with PVT treated initially for 2 weeks with danaparoid sodium were enrolled in this retrospective cohort study. Treatment was later switched to either edoxaban (n = 20) or warfarin (n = 30). We compared the efficacy and safety of edoxaban and warfarin for up to 6 months. The PVT volume was measured by dynamic computed tomography before treatment, at 2 weeks, and at 1, 3, and 6 months.

RESULTS

There were no significant differences in the clinical characteristics of patients in the two groups. Treatment with edoxaban reduced the volume of PVT from 1.42 cm³ at 2 weeks to 0.42 cm³ at 6 months, and prevented exacerbation of PVT at 6 months after treatment with danaparoid sodium (P = 0.016). In contrast, treatment with warfarin resulted in increased PVT volume from 1.73 cm³ at 2 weeks to 2.85 cm³ at 6 months, despite the control of the international normalized ratio in 57% of the patients (P = 0.005). Multivariate regression analysis identified edoxaban therapy as the single significant and independent determinant of PVT reduction at 6 months (P = 0.0014, hazard ratio 6.400). Clinically significant gastrointestinal bleeding was encountered in 3 of 20 (15%) patients of the edoxaban group and 2 of 30 (7%) of the warfarin group (P = 0.335).

CONCLUSION

Edoxaban following danaparoid sodium is an effective anticoagulant and could be potentially considered as one of the treatment options for PVT in cirrhotic patients.

Pharmacokinetics and Pharmacodynamics of Edoxaban, a Non-Vitamin K Antagonist Oral Anticoagulant that Inhibits Clotting Factor Xa

Edoxaban, a once daily non-vitamin K antagonist oral anticoagulant, is a direct, selective, reversible inhibitor of factor Xa (FXa). In healthy subjects, single oral doses of edoxaban result in peak plasma concentrations within 1.0–2.0 h of administration, followed by a biphasic decline. Exposure is approximately dose proportional for once daily doses of 15–150 mg. Edoxaban is predominantly absorbed from the upper gastrointestinal tract, and oral bioavailability is approximately 62 %. Food does not affect total exposure to edoxaban. The terminal elimination half-life in healthy subjects ranges from 10 to 14 h, with minimal accumulation upon repeat once daily dosing up to doses of 120 mg. The steady-state volume of distribution is approximately 107 L, and total clearance is approximately 22 L/h; renal clearance accounts for approximately 50 % of total clearance, while metabolism and biliary secretion account for the remaining 50 %. Intrinsic factors, such as age, sex and race, do not affect edoxaban pharmacokinetics after renal function is taken into account. Oral administration of edoxaban results in rapid changes in anticoagulatory biomarkers, with peak effects on anticoagulation markers (such as anti-FXa), the prothrombin time and the activated partial thromboplastin time occurring within 1–2 h of dosing.

Italian intersociety consensus on DOAC use in internal medicine

The direct oral anticoagulants (DOACs) are drugs used in clinical practice since 2009 for the prevention of stroke or systemic embolism in non-valvular atrial fibrillation, and for the treatment and secondary prevention of venous thromboembolism. The four DOACs, including the three factor Xa inhibitors (rivaroxaban, apixaban and edoxaban) and one direct thrombin inhibitor (dabigatran) provide oral anticoagulation therapy alternatives to Vitamin K antagonists (VKAs). Despite their clear advantages, the DOACs require on the part of the internist a thorough knowledge of their pharmacokinetic and pharmacodynamic characteristics to ensure their correct use, laboratory monitoring and the appropriate management of adverse events. This document represents a consensus paper on the use of DOACs by representatives of three Italian scientific societies: the Italian Society of Internal Medicine (SIMI), the Federation of the Associations of Hospital Managers (FADOI), and the Society for the Study of Haemostasis and Thrombosis (SISET). This document formulates expert opinion guidance for pragmatic managing, monitoring and reversing the anticoagulant effect of DOACs in both chronic and emergency settings. This practical guidance may help the internist to create adequate protocols for patients hospitalized ion internal medicine wards, where patients are often elderly subjects affected by poly-morbidities and renal insufficiency, and, thus, require particular attention to drug-drug interactions and peri-procedural protocols.

Laboratory Assessment of the Anticoagulant Activity of Direct Oral Anticoagulants: A Systematic Review

BACKGROUND

Direct oral anticoagulants (DOACs) are the treatment of choice for most patients with atrial fibrillation and/or noncancer-associated venous thromboembolic disease. Although routine monitoring of these agents is not required, assessment of anticoagulant effect may be desirable in special situations. The objective of this review was to summarize systematically evidence regarding laboratory assessment of the anticoagulant effects of dabigatran, rivaroxaban, apixaban, and edoxaban.

METHODS

PubMed, Embase, and Web of Science were searched for studies reporting relationships between drug levels and coagulation assay results.

RESULTS

We identified 109 eligible studies: 35 for dabigatran, 50 for rivaroxaban, 11 for apixaban, and 13 for edoxaban. The performance of standard anticoagulation tests varied across DOACs and reagents; most assays, showed insufficient correlation to provide a reliable assessment of DOAC effects. Dilute thrombin time (TT) assays demonstrated linear correlation (r2 = 0.67-0.99) across a range of expected concentrations of dabigatran, as did ecarin-based assays. Calibrated anti-Xa assays demonstrated linear correlation (r2 = 0.78-1.00) across a wide range of concentrations for rivaroxaban, apixaban, and edoxaban.

CONCLUSIONS

An ideal test, offering both accuracy and precision for measurement of any DOAC is not widely available. We recommend a dilute TT or ecarin-based assay for assessment of the anticoagulant effect of dabigatran and anti-Xa assays with drug-specific calibrators for direct Xa inhibitors. In the absence of these tests, TT or APTT is recommended over PT/INR for assessment of dabigatran, and PT/INR is recommended over APTT for detection of factor Xa inhibitors. Time since last dose, the presence or absence of drug interactions, and renal and hepatic function should impact clinical estimates of anticoagulant effect in a patient for whom laboratory test results are not available.

Laboratory measurement of the non-vitamin K antagonist oral anticoagulants: selecting the optimal assay based on drug, assay availability, and clinical indication

Although the non-vitamin K antagonist oral anticoagulants (NOACs) do not require routine monitoring, there are special circumstances in which laboratory measurement may be warranted. The objectives of this review are to summarize evidence on the influence of the NOACs on coagulation tests and provide practical guidance to clinicians on measurement and interpretation of coagulation assays in NOAC-treated patients. Selection of an appropriate assay for NOAC measurement depends on the drug, clinical objective, and assay availability. Separate suggestions for assay selection are provided depending on whether specialized assays are available or whether choice is limited to conventional coagulation assays such as the prothrombin time (PT) and activated partial thromboplastin time (APTT). The dilute thrombin time (TT) and ecarin-based assays are able to quantify dabigatran across a broad range of concentrations, but are not widely available. A normal TT excludes clinically relevant levels. A normal APTT probably excludes excess levels of dabigatran, but does not rule out typical on-therapy drug concentrations. The PT is insufficiently sensitive to dabigatran to be useful in most situations. Factor Xa inhibitors may be quantified with an anti-Xa assay calibrated with drug-specific standards. A normal PT probably excludes excess levels of rivaroxaban and edoxaban, but not typical on-therapy levels of these agents. The PT is less sensitive to apixaban. Depending on the sensitivity of the thromboplastin reagent, a normal PT may not exclude excess levels of apixaban. The APTT has inadequate sensitivity to factor Xa inhibitors and is not recommended for their measurement.

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.

Measurement and reversal of the direct oral anticoagulants

Direct oral anticoagulants (DOACs) offer noninferior efficacy and improved safety compared to vitamin K antagonists (VKAs) for the prevention and treatment of venous thromboembolism and for the prevention of stroke and systemic embolism in nonvalvular atrial fibrillation. Unlike VKAs, DOACs do not require routine laboratory monitoring of anticoagulant effect and dose adjustment. In certain situations, however, laboratory assessment of anticoagulant effect may be desirable. Here we review the utility of currently available assays for assessment of DOAC effect and recommend an optimal assessment strategy for each drug, including calibrated dilute thrombin time or ecarin-based assays for dabigatran and calibrated anti-Xa activity assays for the factor Xa inhibitors. We also discuss reversal strategies, both specific and nonspecific, for each drug, including the preferential use of idarucizumab for the reversal of dabigatran and two agents, andexanet and ciraparantag, currently under development for the reversal of rivaroxaban, apixaban, and edoxaban.

The effect of a dual or a triple antithrombotic therapy with apixaban on thrombus formation in vivo and in an ex vivo perfusion chamber model: An open-label, controlled, sequential study

BACKGROUND

There is a need to optimize pharmacological treatment in patients with acute coronary syndrome and concomitant atrial fibrillation, in particular with newer antithrombotic medicines. We have therefore studied if dual or triple combination of antithrombotic agents exert similar effects on coagulation activation in an in vivo model in the skin microvasculature and in an ex vivo perfusion chamber.

METHODS AND RESULTS

Shed blood platelet activation (β-thromboglobulin [β-TG]), thrombin generation (thrombin-antithrombin complex [TAT]) and volume as well as markers of thrombus size (D-dimer) and its platelet content (P-selectin) in a perfusion chamber were studied in a sequential, open-label, parallel group trial in 40 healthy male volunteers (n = 20 per group). Subjects received ticagrelor and apixaban without or with acetylsalicylic acid (ASA). Outcome parameters were assessed at 3 hours after therapy dosing, and at steady-state trough and peak conditions.A triple or dual therapy induced a comparable decrease in shed blood β-TG at 3 hours after therapy dosing but was more pronounced at steady-state conditions with the more intense treatment combination. During both antithrombotic regimens a similarly sustained inhibition in thrombin generation was observed which was accompanied by comparable increases in shed blood volume. In contrast, no treatment effect could be observed in the perfusion chamber experiment.

CONCLUSION

Ticagrelor and apixaban with or without ASA inhibit platelet activation and thrombin formation in vivo in healthy subjects. Platelet inhibition was greater at steady-state conditions after triple therapy administration.

Laboratory measurement of the anticoagulant activity of edoxaban: a systematic review

Edoxaban, an oral direct inhibitor of factor Xa, was recently approved in the United States and Japan for prevention of stroke and systemic embolism in patients with non-valvular atrial fibrillation and for treatment of venous thromboembolism (VTE). It is also licensed in Japan for prevention of VTE after major orthopedic surgery. Although routine laboratory monitoring of edoxaban is not required, laboratory measurement may be desirable in special circumstances. Our objective was to provide a systematic review of current evidence on laboratory measurement of the anticoagulant activity of edoxaban. PubMed and the Cochrane Library were searched for studies that reported a relationship between coagulation tests and plasma edoxaban levels. Study quality was assessed using Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2). We identified 9 eligible studies. Anti-Xa activity is linear across a broad range of drug levels (R (2) > 0.95) and may be used for edoxaban quantification. The assay shows greater variability at above on-therapy drug concentrations. The PT is less sensitive to edoxaban. A normal prothrombin time may not exclude clinically relevant on-therapy drug levels. The activated partial thromboplastin time has insufficient sensitivity to edoxaban for measurement of its anticoagulant activity. Edoxaban exhibits variable effects on coagulation assays. Understanding these effects facilitates interpretation of test results in edoxaban-treated patients. More data on the relationship between drug levels, coagulation test results, and clinical outcomes in patients are needed.

Edoxaban for reducing the risk of stroke and systemic embolism in patients with non-valvular atrial fibrillation

INTRODUCTION

Oral anticoagulation is central to the management of patients with atrial fibrillation (AF) and at least one additional stroke risk factor. For decades, the vitamin K antagonists (e.g. warfarin) remained the only oral anticoagulant available for stroke prevention in AF. The non-vitamin K oral anticoagulants (NOACs) are now available, and these drugs include the direct thrombin inhibitors and factor Xa inhibitors. The latter class includes edoxaban, which has recently been approved for stroke prevention in AF by the United States Food and Drug Administration and the European Medicine Agency. In line with other NOACs, edoxaban avoids the many limitations of warfarin associated with variability of anticoagulation effect and multiple food and drug interactions.

AREAS COVERED

In this review, the currently available evidence on edoxaban in patients with non-valvular AF is discussed. The pharmacology, efficacy and safety, and current aspects of use of edoxaban in patients with non-valvular AF for stroke and thromboembolism prevention are reviewed.

EXPERT OPINION

Phase III trials on edoxaban for stroke prevention in non-valvular AF confirms non-inferiority of edoxaban compared to well-managed warfarin both in terms of efficacy and safety. Currently ongoing and future trials as well as real-world data are warranted to confirm its effectiveness and safety for chronic anticoagulation and improve evidence in other areas which are lacking evidence where NOAC use remains controversial.

Safety, tolerability, and efficacy of idarucizumab for the reversal of the anticoagulant effect of dabigatran in healthy male volunteers: a randomised, placebo-controlled, double-blind phase 1 trial

BACKGROUND

Idarucizumab is a monoclonal antibody fragment that binds dabigatran with high affinity in a 1:1 molar ratio. We investigated the safety, tolerability, and efficacy of increasing doses of idarucizumab for the reversal of anticoagulant effects of dabigatran in a two-part phase 1 study (rising-dose assessment and dose-finding, proof-of-concept investigation). Here we present the results of the proof-of-concept part of the study.

METHODS

In this randomised, placebo-controlled, double-blind, proof-of-concept phase 1 study, we enrolled healthy volunteers (aged 18-45 years) with a body-mass index of 18·5-29·9 kg/m(2) into one of four dose groups at SGS Life Sciences Clinical Research Services, Belgium. Participants were randomly assigned within groups in a 3:1 ratio to idarucizumab or placebo using a pseudorandom number generator and a supplied seed number. Participants and care providers were masked to treatment assignment. All participants received oral dabigatran etexilate 220 mg twice daily for 3 days and a final dose on day 4. Idarucizumab (1 g, 2 g, or 4 g 5-min infusion, or 5 g plus 2·5 g in two 5-min infusions given 1 h apart) was administered about 2 h after the final dabigatran etexilate dose. The primary endpoint was incidence of drug-related adverse events, analysed in all randomly assigned participants who received at least one dose of dabigatran etexilate. Reversal of diluted thrombin time (dTT), ecarin clotting time (ECT), activated partial thromboplastin time (aPTT), and thrombin time (TT) were secondary endpoints assessed by measuring the area under the effect curve from 2 h to 12 h (AUEC2-12) after dabigatran etexilate ingestion on days 3 and 4. This trial is registered with ClinicalTrials.gov, number NCT01688830.

FINDINGS

Between Feb 23, and Nov 29, 2013, 47 men completed this part of the study. 12 were enrolled into each of the 1 g, 2 g, or 5 g plus 2·5 g idarucizumab groups (nine to idarucizumab and three to placebo in each group), and 11 were enrolled into the 4 g idarucizumab group (eight to idarucizumab and three to placebo). Drug-related adverse events were all of mild intensity and reported in seven participants: one in the 1 g idarucizumab group (infusion site erythema and hot flushes), one in the 5 g plus 2·5 g idarucizumab group (epistaxis); one receiving placebo (infusion site haematoma), and four during dabigatran etexilate pretreatment (three haematuria and one epistaxis). Idarucizumab immediately and completely reversed dabigatran-induced anticoagulation in a dose-dependent manner; the mean ratio of day 4 AUEC2-12 to day 3 AUEC2-12 for dTT was 1·01 with placebo, 0·26 with 1 g idarucizumab (74% reduction), 0·06 with 2 g idarucizumab (94% reduction), 0·02 with 4 g idarucizumab (98% reduction), and 0·01 with 5 g plus 2·5 g idarucizumab (99% reduction). No serious or severe adverse events were reported, no adverse event led to discontinuation of treatment, and no clinically relevant difference in incidence of adverse events was noted between treatment groups.

INTERPRETATION

These phase 1 results show that idarucizumab was associated with immediate, complete, and sustained reversal of dabigatran-induced anticoagulation in healthy men, and was well tolerated with no unexpected or clinically relevant safety concerns, supporting further testing. Further clinical studies are in progress.

FUNDING

Boehringer Ingelheim Pharma GmbH & Co KG.

Antithrombotic triple therapy and coagulation activation at the site of thrombus formation: a randomized trial in healthy subjects

BACKGROUND

Patients with acute coronary syndrome and concomitant atrial fibrillation may require antithrombotic triple therapy but clinical evidence of safety and efficacy is poor. We have therefore studied the combination of different antithrombotic medicines for coagulation activation in an in vivo model in the skin microvasculature.

METHODS AND RESULTS

Platelet activation (β-thromboglobulin [β-TG]) and thrombin generation (prothrombin fragment 1 + 2 [F1+2 ], thrombin-antithrombin complex [TAT]) were studied in an open-label, randomized, parallel group trial in 60 healthy male subjects (n = 20 per group) who received ticagrelor and acetylsalicylic acid (ASA) in combination with dabigatran (150 mg bid), rivaroxaban (20 mg od) or phenprocoumon (INR 2.0-3.0). Coagulation biomarkers in shed blood were assessed at 3 h after monotherapy with the medicines under study, at 3 h after triple therapy dosing and at steady state trough conditions. Single doses of ticagrelor, dabigatran or rivaroxaban caused comparable decreases in shed blood β-TG and were more pronounced than phenprocoumon at an INR of 2.0-3.0. In contrast, thrombin generation was more affected by rivaroxaban and phenprocoumon than by dabigatran. During triple therapy a similarly sustained inhibition of platelet activation and thrombin generation with a maximum decrease of β-TG, F1+2 and TAT at 3 h post-dosing was noted, which remained below pre-dose levels at trough steady state.

CONCLUSION

A triple therapy at steady state with ticagrelor plus ASA in combination with dabigatran or rivaroxaban is as effective as a combination with phenprocoumon for platelet activation and thrombin generation in vivo.

A randomized trial of the safety, pharmacokinetics and pharmacodynamics of edoxaban, an oral factor Xa inhibitor, following a switch from warfarin

AIMS

To evaluate the safety, tolerability, pharmacokinetics and pharmacodynamics of edoxaban, an oral direct factor Xa inhibitor, in healthy subjects switching from warfarin.

METHODS

Seventy-two subjects were randomized to edoxaban 60 mg once daily (n = 48) or matching placebo (n = 24) for 5 days at 24 h after the last dose of warfarin treatment (INR 2.0 to 3.0). Safety/tolerability was the primary outcome measure. Pharmacokinetics, INR, aPTT, anti-FXa, thrombin generation and other coagulation assays were assessed.

RESULTS

Seventy-two subjects were randomized and 64 subjects received at least one dose of edoxaban (n = 43) or placebo (n = 21) after achieving a target INR of 2.0 to 3.0 on warfarin treatment. Edoxaban 60 mg administered 24 h post-warfarin appeared to be safe and well tolerated. Adverse events were similar across treatments. For bleeding-related adverse events, eight subjects tested positive for faecal occult blood, five subjects during warfarin treatment and three subjects during edoxaban treatment. The mean (SD) baseline (post-dose of warfarin) INR was 2.31 (0.193) which increased to 3.84 (0.744) over 2 h during the edoxaban treatment (P < 0.0001 vs. placebo), returning to post-warfarin baseline within 12 h. A similar time course of effects for the other coagulation assays was observed in accordance with the drugs' mechanisms of action.

CONCLUSION

In this study of healthy subjects, edoxaban administered 24 h after the last dose of warfarin was safe and well tolerated with transient increases across the various coagulation assays above post-warfarin baseline levels.

Reversal of novel oral anticoagulants in patients with major bleeding

Novel oral anticoagulants (NOACs) that directly inhibit thrombin (dabigatran) or factor Xa (rivaroxaban, apixaban, edoxaban) are effective therapies for the prevention and treatment of thromboembolism with reduced bleeding complications compared with warfarin for some indications. However, specific antidotes to reverse the anticoagulant activity of NOACs in the event of major bleeding are not available. Evidence supporting non-specific prohemostatic therapies (prothrombin complex concentrate [PCC], activated prothrombin complex concentrate [aPCC], recombinant factor VIIa) in this setting is limited to healthy human volunteers, animal models, and in vitro studies. Clinical outcome data are lacking. Administration of PCC or aPCC may be considered in addition to supportive measures for patients with severe or life-threatening bleeding. Clinical studies are needed to establish the efficacy and safety of these treatments. Target-specific antidotes are in development and hold promise for NOAC reversal, but require further investigation.

Design of a medication reconciliation application: facilitating clinician-focused decision making with data from multiple sources

BACKGROUND

Medication reconciliation is an essential, but resource-intensive process without a "gold standard" to measure medication adherence. Medication reconciliation applications that focus on facilitating clinicians' decision-making are needed. Since no single available source of medication information is adequate, combining data sources may improve usefulness and outcomes.

OBJECTIVES

We aimed to design a medication reconciliation application that could incorporate multiple data sources and convey information about patients' adherence to prescribed medications. We discuss design decisions integral to developing medication reconciliation applications for the electronic health record. The discussion is relevant for health IT developers, clinical providers, administrators, policy makers, and patients. Three hypotheses drove our design of this application: 1) Medication information comes from a variety of sources, each having benefits and limitations; 2) improvements in patient safety can result from reducing the cognitive burden and time required to identify medication changes; 3) a well-designed user interface can facilitate clinicians' understanding and clinical decision making.

METHODS

Relying on evidence about interface design and medication reconciliation, an application for the electronic health record at an academic medical center in the U.S. was designed. Multiple decisions that considered the availability, value, and display of the medication data are explored: Information from different sources; interval changes in medications; the sorting of information; and the user interface.

RESULTS

THE PROTOTYPE MEDICATION RECONCILIATION APPLICATION DESIGN REFLECTS THE VISUAL ORGANIZATION, CATEGORIZATION, MODALITY OF INTERACTIONS, AND PRESENTATION OF MEDICATION INFORMATION FROM THREE DATA SOURCES: patient, electronic health record, and pharmacy.

CONCLUSIONS

A new medication reconciliation user interface displays information from multiple sources, indicates discrepancies among sources, displays information about adherence, and sorts the medication list in a useful display for clinical decision making. Gathering, verifying, and updating medication data are resource-intensive processes. The outcomes of integrating, interpreting, and presenting medication information from multiple sources remain to be studied.

Characterisation of exposure versus response of edoxaban in patients undergoing total hip replacement surgery

Edoxaban is an oral direct factor Xa inhibitor approved for the prevention of venous thromboembolism (VTE) in Japan. The objectives of this analysis were to characterise the population pharmacokinetics (PK) of edoxaban and the relationships between edoxaban exposure and clinical outcomes in a phase IIb study of surgical patients following total hip replacement (THR). A total of 1,795 subjects from a phase IIb study, 10 phase I studies, and three phase IIa studies were included in the PK analysis. The exposure-response analysis included data from surgical patients assigned to edoxaban in the phase IIb study. Edoxaban disposition in healthy and post-surgical patients was well-described with a linear, two-compartment model. Creatinine clearance was significantly correlated with edoxaban clearance and the rate of oral absorption was affected by surgery. The probability of a post-operative VTE was significantly correlated with steady-state metrics of edoxaban exposure estimated for each subject by Bayesian post-hoc methods with age and gender being the significant and expected covariates. The incidence of bleeding was low in these studies and hence no exposure-response relationship could be identified. These analyses suggest that edoxaban has a predictable anticoagulant effect in this patient population leading to dose-proportional reduction in incidence of VTE with low incidence of bleeding.