2021 Update of the International Council for Standardization in Haematology Recommendations for Laboratory Measurement of Direct Oral Anticoagulants.

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

Expert consensus regarding standardization of sample preparation for clotting time assays.

Accurate clotting time assay results are vital, as the test is employed to indicate the amount of oral anticoagulant to be prescribed, while it is also used for screening the hemorrhagic and thrombotic diseases. The procedure chosen for preparation of a patient blood sample including centrifugation can contribute to significant differences in the results obtained. Thus, for the purpose of proposing a standardized method to appropriately prepare blood samples prior to assay, the Japanese Society of Laboratory Hematology organized the Working Group for Standardization of Sample Preparation for Clotting Time Assays (WG). Following reviews of previously announced guidelines and original experimental results, consensus was obtained by the WG, with the main findings as follows. (1) The recommended anticoagulant in the blood collection tube is sodium citrate solution at 0.105-0.109 M (3.13-3.2%). (2) Whole blood samples should be stored at room temperature (18-25 ˚C) within 1 h of collection from the patient. (3) For plasma preparation, centrifugation at 1500 × g should be performed for at least 15 min or at 2000 × g for at least 10 min at room temperature. (4) After the plasma sample is prepared, it should be stored at room temperature and assayed within 4 h.

International Council for Standardization in Haematology (ICSH) Recommendations for Laboratory Measurement of Direct Oral Anticoagulants.

This guidance document was prepared on behalf of the International Council for Standardization in Haematology (ICSH) for providing haemostasis-related guidance documents for clinical laboratories. This inaugural coagulation ICSH document was developed by an ad hoc committee, comprised of international clinical and laboratory direct acting oral anticoagulant (DOAC) experts. The committee developed consensus recommendations for laboratory measurement of DOACs (dabigatran, rivaroxaban, apixaban and edoxaban), which would be germane for laboratories assessing DOAC anticoagulation. This guidance document addresses all phases of laboratory DOAC measurements, including pre-analytical (e.g. preferred time sample collection, preferred sample type, sample stability), analytical (gold standard method, screening and quantifying methods) and post analytical (e.g. reporting units, quality assurance). The committee addressed the use and limitations of screening tests such as prothrombin time, activated partial thromboplastin time as well as viscoelastic measurements of clotting blood and point of care methods. Additionally, the committee provided recommendations for the proper validation or verification of performance of laboratory assays prior to implementation for clinical use, and external quality assurance to provide continuous assessment of testing and reporting method.

Edoxaban versus enoxaparin for the prevention of venous thromboembolism after total knee or hip arthroplasty: pooled analysis of coagulation biomarkers and primary efficacy and safety endpoints from two phase 3 trials.

BACKGROUND: The objective of this analysis was to assess the effects of edoxaban compared with enoxaparin on key coagulation biomarkers and present pooled primary efficacy and safety results from phase 3 STARS E-3 and STARS J-V trials for prevention of venous thromboembolism (VTE) after total knee arthroplasty (TKA) or total hip arthroplasty (THA). METHODS: In the randomized, double-blind, double-dummy, multicenter, STARS E-3 and STARS J-V trials, patients received edoxaban 30 mg or enoxaparin 2000 IU (20 mg) twice daily for 11 to 14 days. The studies were conducted in Japan and Taiwan; enoxaparin dosing was based on Japanese label recommendations. The primary efficacy endpoint was incidence of VTE; the safety endpoint was major or clinically relevant nonmajor (CRNM) bleeding. Blood samples were taken at presurgical evaluation, pretreatment (postsurgery), predose on day 7, predose on completion of treatment, and at a follow-up examination 25 to 35 days after the last dose of study drug for D-dimer, prothrombin fragment 1 + 2 (F1+2), and soluble fibrin monomer complex (SFMC) measurement. RESULTS: A total of 716 patients enrolled in STARS E-3 and 610 patients enrolled in STARS J-V; 1326 patients overall. This analysis included 657 patients who received edoxaban 30 mg QD and 650 patients who received enoxaparin 20 mg BID. Incidence of VTE was 5.1 and 10.7% for edoxaban and enoxaparin, respectively (P <0.001). Incidence of combined major and CRNM bleeding was 4.6 and 3.7% for edoxaban and enoxaparin, respectively (P = 0.427). On day 7, mean D-dimer (4.4 vs 5.5 µg/mL), F1+2 (363 vs 463 pmol/L), and SFMC (5.7 vs 6.8 µg/mL) were lower in edoxaban-treated patients relative to enoxaparin-treated patients, respectively (P <0.0001 for all). At end of treatment, mean D-dimer (5.4 vs 6.2 µg/mL), F1+2 (292 vs 380 pmol/L), and SFMC (6.2 vs 7.2 µg/mL) were lower in edoxaban-treated patients relative to enoxaparin-treated patients (P <0.0001 for all). CONCLUSIONS: Edoxaban was superior to enoxaparin in prevention of VTE following TKA and THA, with comparable rates of bleeding events. Relative to enoxaparin, edoxaban significantly reduced D-dimer, F1+2, and SFMC. TRIAL REGISTRATION: Clintrials.gov NCT01181102 and NCT01181167. Both registered 8/12/2010.

Multianalyte Conventional Reference Material (MacRM): A Useful Tool for Nationwide Standardization of Laboratory Measurements for Medical Care-A Model Study in Japan.

BACKGROUND: The Japanese Committee for Clinical Laboratory Standards (JCCLS) has developed a multianalyte conventional reference material (MacRM) for nationwide standardization of laboratory measurements. METHODS: To prepare the MacRM, pooled sera were obtained from healthy Japanese individuals. Target values of the pooled sera for 30 analytes were assigned on the basis of the measurement results of 45 certified clinical laboratories whose calibration was verified by measuring certified reference materials (CRMs) provided by the National Institute of Standards and Technology, the Institute for Reference Materials and Measurements, and JCCLS. Commutability of MacRM was assessed by comparison with results for 150 individual inpatients at Fukuoka University Chikushi Hospital. Survey samples were prepared by essentially the same method for MacRM but without target values. The survey samples were used to assess agreement among 165 laboratories that used various assay kits and platforms calibrated with the MacRM. RESULTS: The commutability of MacRM was confirmed for 30 analytes with sera from 150 individual patients. The imprecision (CV) of measurements of survey samples (high and low concentrations) among the 165 laboratories was 0.4%-10.0%. Twenty-six of 30 analytes were within the goals for interinstitutional allowable bias. An aliquot of MacRM stored frozen at -80 °C remained stable for ≥4 years. CONCLUSIONS: The MacRM was successfully applied as a calibrator to achieve nationwide standardization for 30 analytes measured by 165 laboratories that used various methods from different manufacturers.

Efficacy and safety of edoxaban versus enoxaparin for the prevention of venous thromboembolism following total hip arthroplasty: STARS J-V.

BACKGROUND: In the absence of thromboprophylaxis, patients undergoing total hip arthroplasty (THA) are at increased risk for venous thromboembolism (VTE). The objective of this study was to compare the efficacy and safety of edoxaban with enoxaparin for the prevention of VTE after THA in Japan. METHODS: This was a phase 3, double-blind, double-dummy, noninferiority study. Patients undergoing elective, unilateral primary THA were randomized to receive edoxaban 30 mg once daily (n = 307) or enoxaparin 2000 IU (equivalent to 20 mg) twice daily (n = 303) for 11 to 14 days. The primary efficacy endpoint was the incidence of VTE. Safety endpoints included the incidence of major or clinically relevant nonmajor (CRNM) bleeding. RESULTS: The incidence of VTE, based on venography and clinical surveillance, was 2.4 % in the edoxaban group and 6.9 % in the enoxaparin group (P <0.001). The absolute difference in the incidence of VTE was -4.5 % (95 % confidence interval [CI]: -8.6, -0.9), which was within the noninferiority margin set at 8 % for the difference and established the noninferiority of edoxaban to enoxaparin. Since the upper limit of the 95 % CI of the absolute difference was less than 0 %, the superiority of edoxaban over enoxaparin was demonstrated. The incidence of major or CRNM bleeding was 2.6 % in the edoxaban group and 3.7 % in the enoxaparin group (P = 0.475). CONCLUSIONS: Oral edoxaban 30 mg once daily was superior to subcutaneous enoxaparin 2000 IU twice daily in the prevention of VTE following THA without increasing the risk for major or CRNM bleeding.

A randomized, open-label trial of edoxaban in Japanese patients with severe renal impairment undergoing lower-limb orthopedic surgery.

BACKGROUND: Edoxaban is an oral, direct, factor Xa inhibitor approved in Japan for thromboembolic prophylaxis after lower-limb orthopedic surgery (LLOS), but contraindicated in patients with severe renal impairment (SRI; creatinine clearance [CLCR] ≥15 to <30 mL/min). METHODS: This open-label study compared the safety of edoxaban 15 mg once daily in Japanese patients with SRI to that of edoxaban 30 mg in patients with mild renal impairment (MiRI; CLCR ≥50 to ≤80 mL/min; N = 30) undergoing LLOS. Patients with CLCR ≥20 to <30 mL/min were randomized to receive edoxaban 15 mg (N = 22) or subcutaneous fondaparinux 1.5 mg once daily (N = 21). All patients with CLCR ≥15 to <20 mL/min received edoxaban 15 mg (N = 7). Treatment was administered for 11 to 14 days. RESULTS: Major or clinically relevant non-major bleeding occurred in 6.7%, 3.4%, and 5.0% of patients in the MiRI edoxaban 30-mg, SRI edoxaban 15-mg, and SRI fondaparinux groups, respectively; there were no major bleeding events. No thromboembolic events occurred. At all time points assessed, edoxaban plasma concentrations and changes in coagulation biomarkers were similar between the SRI and MiRI groups. CONCLUSIONS: These results suggest edoxaban 15 mg once daily is well tolerated in Japanese patients with SRI undergoing LLOS. TRIAL REGISTRATION: Clinicaltrials.gov Identifier: NCT01857583.

Safety and efficacy of edoxaban, an oral factor Xa inhibitor, versus enoxaparin for thromboprophylaxis after total knee arthroplasty: the STARS E-3 trial.

INTRODUCTION: This phase 3 trial compared the safety and efficacy of edoxaban, an oral direct factor Xa inhibitor, with enoxaparin sodium (enoxaparin) for thromboprophylaxis after total knee arthroplasty (TKA) in patients in Japan and Taiwan. MATERIALS AND METHODS: In this randomized, double-blind, double-dummy study, patients received oral edoxaban 30 mg once daily beginning 6 to 24 hours postsurgery or enoxaparin 2000 IU (equivalent to 20 mg) subcutaneously twice daily beginning 24 to 36 hours postsurgery for 11 to 14 days. The primary efficacy endpoint was the composite of symptomatic pulmonary embolism and symptomatic and asymptomatic deep vein thrombosis. Safety endpoints included the incidence of major bleeding, clinically relevant non-major (CRNM) bleeding, major bleeding or CRNM bleeding, all bleeding events, adverse events, and adverse drug reactions. RESULTS: Of 716 patients enrolled, 360 and 356 were randomized to receive edoxaban or enoxaparin, respectively. The primary efficacy outcome occurred in 22/299 (7.4%) and 41/295 (13.9%) patients in the edoxaban and enoxaparin groups, respectively (relative risk reduction=46.8%), indicating non-inferiority (P <0.001) and superiority (P=0.010) of edoxaban versus enoxaparin. In the edoxaban and enoxaparin groups, major bleeding occurred in 4/354 (1.1%) versus 1/349 (0.3%) patients (P=0.373); major or CRNM bleeding occurred in 22/354 (6.2%) versus 13/349 (3.7%) patients (P=0.129), respectively. CONCLUSIONS: Edoxaban 30 mg once daily was more effective for thromboprophylaxis than subcutaneous enoxaparin 2000 IU twice daily following TKA and demonstrated a similar incidence of bleeding events.

Safety and efficacy of edoxaban in patients undergoing hip fracture surgery.

INTRODUCTION: Edoxaban is an oral, direct, once-daily factor Xa inhibitor. This study evaluated the safety and efficacy of edoxaban compared to subcutaneous enoxaparin in Japanese patients undergoing hip fracture surgery. MATERIALS AND METHODS: In this multicenter, randomized, open-label, active-comparator, phase 3 trial, 92 patients were randomized 2:1 to receive edoxaban 30mg once daily (n=62) or enoxaparin sodium (enoxaparin) 2000IU (equivalent to 20mg) twice daily (n=30) for 11 to 14days. The primary endpoints were the incidence of major or clinically relevant non-major (CRNM) bleeding and incidence of any bleeding events (major, CRNM, or minor bleeding). Secondary efficacy endpoints included the incidence of thromboembolic events, venous thromboembolism-related deaths, and all-cause deaths. Additional adverse events were recorded throughout the study. RESULTS: In the edoxaban and enoxaparin treatment groups, the incidence of major or CRNM bleeding was 3.4% and 6.9%, respectively, while any bleeding event occurred in 25.4% and 17.2% of patients, respectively. The incidence of thromboembolic events was 6.5% in the edoxaban group and 3.7% in the enoxaparin group. All events were asymptomatic deep vein thrombosis. The incidence of adverse events was 72.9% and 82.8% in the edoxaban and enoxaparin groups, respectively. CONCLUSIONS: Compared to subcutaneous enoxaparin 2000IU twice daily, oral edoxaban 30mg once daily demonstrated similar safety and efficacy in the prevention of thromboembolic events in Japanese patients undergoing hip fracture surgery. CLINICAL TRIALS REGISTRATION NUMBER: NCT01181141.

Epitope mapping for monoclonal antibody reveals the activation mechanism for αVß3 integrin.

Epitopes for a panel of anti-αVß3 monoclonal antibodies (mAbs) were investigated to explore the activation mechanism of αVß3 integrin. Experiments utilizing αV/αIIb domain-swapping chimeras revealed that among the nine mAbs tested, five recognized the ligand-binding ß-propeller domain and four recognized the thigh domain, which is the upper leg of the αV chain. Interestingly, the four mAbs included function-blocking as well as non-functional mAbs, although they bound at a distance from the ligand-binding site. The epitopes for these four mAbs were further determined using human-to-mouse αV chimeras. Among the four, P3G8 recognized an amino acid residue, Ser-528, located on the side of the thigh domain, while AMF-7, M9, and P2W7 all recognized a common epitope, Ser-462, that was located close to the α-genu, where integrin makes a sharp bend in the crystal structure. Fibrinogen binding studies for cells expressing wild-type αVß3 confirmed that AMF-7, M9, and P2W7 were inhibitory, while P3G8 was non-functional. However, these mAbs were all unable to block binding when αVß3 was constrained in its extended conformation. These results suggest that AMF-7, M9, and P2W7 block ligand binding allosterically by stabilizing the angle of the bend in the bent conformation. Thus, a switchblade-like movement of the integrin leg is indispensable for the affinity regulation of αVß3 integrin.

Randomized, multicenter, warfarin-controlled phase II study of edoxaban in Japanese patients with non-valvular atrial fibrillation.

BACKGROUND: Edoxaban is a once-daily (QD) oral, direct factor Xa inhibitor in clinical development for the prevention of stroke in patients with non-valvular atrial fibrillation (NVAF). The aim of this study was to evaluate the safety of edoxaban in Japanese patients with NVAF. METHODS AND RESULTS: A total of 536 NVAF patients (CHADS2 ≥1) were randomized to receive double-blinded edoxaban 30, 45, or 60 mg QD or open-label warfarin (international normalized ratio [INR] 2.0-3.0 for age <70 years; 1.6-2.6 for age ≥70 years) for 12 weeks. The primary endpoint was the incidence of all bleeding events (major, clinically relevant non-major, and minor bleeds). Patients underwent CT and/or MRI to assess asymptomatic intracranial hemorrhage (ICH). Secondary endpoints included thromboembolic events and pharmacodynamic indices. The mean incidence of all bleeding events for edoxaban 30, 45, and 60mg, and warfarin was 18.5%, 22.4%, 27.7%, and 20.0%, respectively. There were no statistically significant differences among the edoxaban groups and no significant differences from the warfarin group. There were no asymptomatic ICH events in any group. One episode of cerebral infarction was observed in the edoxaban 45-mg group. Subgroup analysis suggested low body weight (≤60kg) was associated with higher bleeding risk. CONCLUSIONS: Edoxaban 30, 45, and 60mg QD in patients with NVAF was associated with a numerical increase in all bleeding across the dose range, but this was not statistically significant, nor was any dose compared with warfarin.

Structural requirements for activation in alphaIIb beta3 integrin.

Integrins are postulated to undergo structural rearrangement from a low affinity bent conformer to a high affinity extended conformer upon activation. However, some reports have shown that a bent conformer is capable of binding a ligand, whereas another report has shown that integrin extension does not absolutely lead to activation. To clarify whether integrin affinity is indeed regulated by the so-called switchblade-like movement, we have engineered a series of mutant αIIbß3 integrins that are constrained specifically in either a bent or an extended conformation. These mutant αIIbß3 integrins were expressed in mammalian cells, and fibrinogen binding to these cells was examined. The bent integrins were created through the introduction of artificial disulfide bridges in the ß-head/ß-tail interface. Cells expressing bent integrins all failed to bind fibrinogen unless pretreated with DTT to disrupt the disulfide bridges. The extended integrins were created by introducing N-glycosylation sites in amino acid residues located close to the α-genu, where the integrin legs fold backward. Among these mutants, activation was maximized in one integrin with an N-glycosylation site located behind the α-genu. This extension-induced activation was completely blocked when the swing-out of the hybrid domain was prevented. These results suggest that the bent and extended conformers represent low affinity and high affinity conformers, respectively, and that extension-induced activation depends on the swing-out of the hybrid domain. Taken together, these results are consistent with the current hypothesis that integrin affinity is regulated by the switchblade-like movement of the integrin legs.

Neutrophil elastase and systemic inflammatory response syndrome in the initiation and development of acute lung injury among critically ill patients.

Critically ill patients are commonly associated with systemic inflammatory response syndrome (SIRS) and are at a greater risk of developing acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). Under these conditions, large amounts of various cytokines are produced, which either directly or indirectly induce tissue injury and finally organ dysfunctions, through the activation of neutrophils and as a result of release of cytotoxic molecules, especially neutrophil elastase (NE). In the present study, we determined plasma neutrophil elastase-alpha-1 antitrypsin complex (NE-AT) and elastase digests of cross-linked fibrin (e-XDP) in critically ill patients to elucidate the significance of NE in the initiation and progression of ALI and ARDS in the presence or absence of SIRS. We found significantly increased levels of plasma NE-AT in the patients with ARDS, especially when the definition of SIRS was met. Among ALI/ARDS groups, plasma NE-AT, but not e-XDP, correlated significantly with the decrease in PaO(2)/FIO(2) ratio and the duration of ALI/ARDS. Furthermore, NE-AT, but not e-XDP, significantly increased in subgroups whose PaO(2)/FIO(2) ratio decreased by more than 20%. Such correlations and differences between the subgroups were not observed in the non-ALI patients. From these results, we speculate that NE-AT, but not e-XDP, may be predictive of progressive lung injury in the early stage of ALI and ARDS.

Inhibition of cellular adhesion in human umbilical vein endothelial cells by NF-kappaB inhibitor DHMEQ under flow.

We previously designed and synthesized DHMEQ as an inhibitor of NF-kappaB. In the present study, we looked into the effect of DHMEQ on the cell adhesion in human umbilical vein endothelial cells (HUVEC) under flow. We used freshly prepared HUVEC and human mononuclear cells throughout the experiment. DHMEQ inhibited TNF-alpha-, IL-1beta-, and LPS-induced NF-kappaB activation in HUVEC. It also inhibited TNF-alpha-induced expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin. DHMEQ also inhibited TNF-alpha-induced mononuclear cell-HUVEC adhesion. The effect of DHMEQ was more prominent when the cells were under shear stress. DHMEQ inhibited the adhesion between HUVEC and HT-29 colon cancer cells more clearly under the flow condition than under the static condition of the culture medium. These results suggest that DHMEQ, being a unique inhibitor of NF-kappaB, may be effective in suppressing atherosclerosis and metastasis by inhibiting the expression of adhesion molecules.