Publications by authors named "Yoshiyuki Morishima"

45 Publications

Prolongation of clot lysis time by a direct thrombin inhibitor melagatran mediated by paradoxical enhancement of thrombin generation: comparison with a direct factor Xa inhibitor edoxaban.

Blood Coagul Fibrinolysis 2021 Apr;32(3):209-215

Biological Research Laboratories, R & D Division, Daiichi Sankyo Co., Ltd, Tokyo, Japan.

Previously, we reported that a direct thrombin inhibitor melagatran paradoxically increased thrombin generation in human plasma in the presence of thrombomodulin. The aim of this study is to test the hypothesis that melagatran may exert a deleterious effect on tissue-type plasminogen activator (t-PA)-induced fibrinolysis via enhancement of thrombin generation and subsequent activation of thrombin-activatable fibrinolysis inhibitor (TAFI) and factor XIII (FXIII). Clot formation in human plasma containing t-PA and thrombomodulin was induced by tissue factor. The absorbance at 405 nm was measured to obtain clot lysis time. Effects of melagatran and a factor Xa inhibitor edoxaban on clot lysis time were determined. In the presence of thrombomodulin, melagatran significantly prolonged clot lysis time, but edoxaban shortened it. In the absence of thrombomodulin, melagatran did not inhibit fibrinolysis. Prolongation of clot lysis time by melagatran was reversed by activated protein C (which suppressed thrombin generation increased by melagatran) and a TAFIa inhibitor. Melagatran significantly suppressed plasmin generation, while edoxaban significantly increased it. However, both melagatran and edoxaban suppressed FXIII activation. In the clot formed in the presence of melagatran and edoxaban, the fibrin fibre was thin compared with control, showing no clear difference in the clot structures between melagatran and edoxaban. These results indicated that melagatran, not edoxaban, prolonged clot lysis time through the paradoxical enhancement of thrombin generation, and subsequent TAFI activation and inhibition of plasmin generation. Neither FXIII activation nor change in fibrin clot structure contributed to the inhibition of fibrinolysis by melagatran.
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http://dx.doi.org/10.1097/MBC.0000000000001020DOI Listing
April 2021

Edoxaban, a direct oral factor Xa inhibitor, ameliorates coagulation, microvascular thrombus formation, and acute liver injury in a lipopolysaccharide-induced coagulopathy model in rats.

J Thromb Thrombolysis 2021 Feb 3. Epub 2021 Feb 3.

Pharmacovigilance Department, Daiichi Sankyo Co., Ltd., Tokyo, 103-8426, Japan.

Infection increases the risk of thrombosis through the activation of inflammation and coagulation. Edoxaban, a direct oral factor Xa inhibitor, is used for the prevention and treatment of thrombotic diseases. The aim of this study was to determine the effects of edoxaban on microvascular thrombus formation in a rat model of lipopolysaccharide (LPS)-induced coagulopathy. Rats were intravenously injected with 7.5 mg/kg of LPS (Escherichia coli 055:B5). Immediately after LPS injection, the rats were treated with subcutaneous injection of edoxaban. At 2 and 6 h after the injection of LPS, biomarkers of coagulation and organ damages and inflammatory cytokines were measured. Microvascular thrombus formation in organs was evaluated using I-fibrinogen (human) or by the pathological analysis. Mortality was examined 24 h after LPS injection. After the injection of LPS, D-dimer and thrombin-antithrombin complex increased and platelet numbers decreased, indicating the activation of coagulation. Microvascular thrombi were found in the liver. Markers of liver injury (aspartate aminotransferase and alanine aminotransferase) also increased. Treatment with edoxaban attenuated the changes in the coagulation markers and microvascular thrombus formation in the liver. Edoxaban suppressed the increase in the liver injury markers and reduced the mortality. Edoxaban did not affect the levels of inflammatory cytokines. In conclusions, edoxaban significantly inhibited the activation of coagulation, the formation of microvascular thrombus in the liver and the liver damage, and reduced mortality in rats injected with LPS. These results suggest that the FXa inhibition by edoxaban might be a beneficial therapy for the management of infection-associated thrombosis.
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http://dx.doi.org/10.1007/s11239-021-02381-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7856452PMC
February 2021

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.

Thromb J 2020 12;18:10. Epub 2020 Jun 12.

Medical Science Department, Daiichi Sankyo Co., Ltd., 3-5-1 Nihonbashi Honcho, Chuo-ku, Tokyo, 103-8426 Japan.

Background: Dual therapy with a direct oral anticoagulant (DOAC) plus a P2Y receptor inhibitor is recommended in patients with nonvalvular atrial fibrillation who undergo percutaneous coronary intervention. Thus, we evaluated the effects of DOAC edoxaban plus P2Y 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 P2Y 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.
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http://dx.doi.org/10.1186/s12959-020-00223-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7291522PMC
June 2020

Exploratory Analysis of Circulating miRNA Signatures in Atrial Fibrillation Patients Determining Potential Biomarkers to Support Decision-Making in Anticoagulation and Catheter Ablation.

Int J Mol Sci 2020 Apr 1;21(7). Epub 2020 Apr 1.

Department of Cardiovascular Medicine, The Cardiovascular Institute, Tokyo 106-0031, Japan.

Novel biomarkers are desired to improve risk management for patients with atrial fibrillation (AF). We measured 179 plasma miRNAs in 83 AF patients using multiplex qRT-PCR. Plasma levels of eight (i.e., hsa-miR-22-3p, hsa-miR-128-3p, hsa-miR-130a-3p, hsa-miR-140-5p, hsa-miR-143-3p, hsa-miR-148b-3p, hsa-miR-497-5p, hsa-miR-652-3p) and three (i.e., hsa-miR-144-5p, hsa-miR-192-5p, hsa-miR-194-5p) miRNAs showed positive and negative correlations with CHADS-VASc scores, respectively, which also showed negative and positive correlations with catheter ablation (CA) procedure, respectively, within the follow-up observation period up to 6-month after enrollment. These 11 miRNAs were functionally associated with TGF-β signaling and androgen signaling based on pathway enrichment analysis. Seven of possible target genes of these miRNAs, namely , , , , , and were found to be modulated by more than four miRNAs of the eleven. Of them, TGFBR1, PDGFRA, ZEB1 and BCL2 are reported to exert pro-fibrotic functions, suggesting that dysregulations of these eleven miRNAs may reflect pro-fibrotic condition in the high-risk patients. Although highly speculative, these miRNAs may potentially serve as potential biomarkers, providing mechanistic and quantitative information for pathophysiology in daily clinical practice with AF such as possible pro-fibrotic state in left atrium, which would enhance the risk of stroke and reduce the preference for performing CA.
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http://dx.doi.org/10.3390/ijms21072444DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7178177PMC
April 2020

Association between plasma concentration of edoxaban determined by direct and indirect methods in Japanese patients with non-valvular atrial fibrillation (CVI ARO 7).

Heart Vessels 2020 Mar 14;35(3):409-416. Epub 2019 Sep 14.

Department of Cardiovascular Medicine, The Cardiovascular Institute, 3-2-19 Nishiazabu, Minato-Ku, Tokyo, 106-0031, Japan.

Direct oral anticoagulants, including edoxaban, primarily do not need routine monitoring of the anticoagulant effect. However, extremely high/low plasma concentrations of edoxaban (PC-Ed) should be properly evaluated, especially when patients under anticoagulation therapy are at an emergency state. For this purpose, PC-Ed determined by an anti-Xa assay (indirect PC-Ed) is more convenient and, therefore, more useful compared with PC-Ed determined by an LC-MS/MS (direct PC-Ed) in daily clinical practice. Consecutive 97 patients with non-valvular atrial fibrillation (NVAF) under edoxaban therapy were evaluated, in whom edoxaban 60/30 mg doses were prescribed for 48/49 patients, 71 (73.2%) were men, and the average age was 69 years. CHADS score 0, 1, and ≥ 2 were 26.8%, 44.3%, and 28.9%, while CHADS-VASc score 0, 1, and ≥ 2 were 14.4%, 16.5%, and 69.1%, respectively. Median values of direct and indirect PC-Ed by LC-MS/MS and anti-Xa assay were 187.1 and 176.1 ng/mL at peak (2-4 h post-dose) and 14.4 and 17.5 ng/mL at trough (pre-dose), respectively. The PC-Ed at peak and trough by two methods were significantly correlated, and the correlation coefficients were r = 0.973 and 0.963 (both, p < 0.0001), respectively. By a Bland-Altman plot, mean differences between the direct and indirect PC-Ed [lower to upper percent limit of agreement] were - 4.87 [- 46.71 to 36.98] and 4.66 [- 1.37 to 10.69] ng/mL at peak and trough, respectively. Moreover, mean % error for difference between the direct and indirect PC-Ed [lower to upper percent limit of agreement] was - 1.22 [- 20.59 to 18.14] and 31.75 [- 14.03 to 77.53] % at peak and trough, respectively, where the % error extremely increased around the lower limit of detection (LLOD) in the anti-Xa assay. Strong similarity was observed between the direct and indirect PC-Ed, especially at peak. The indirect PC-Ed was higher than the direct PC-Ed, especially around the LLOD, suggesting the need for caution when we use the anti-Xa assay for measurement of trough PC-Ed (UMIN 000032492).
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http://dx.doi.org/10.1007/s00380-019-01501-2DOI Listing
March 2020

Combined effect of a direct oral anticoagulant edoxaban and an inhibitor of activated thrombin-activatable fibrinolysis inhibitor on clot lysis.

J Thromb Thrombolysis 2020 Jan;49(1):94-99

End-Organ Disease Laboratories, Daiichi Sankyo Co., Ltd., Tokyo, Japan.

Fibrinolysis is regulated by the thrombin/thrombin-activatable fibrinolysis inhibitor (TAFI) system. Thus, anticoagulants and inhibitors of TAFI are expected to accelerate fibrinolysis. The combined effects of an anticoagulant and a TAFIa inhibitor on fibrinolysis remain unknown. The aim of this study was to evaluate the combined effect of edoxaban, an oral direct factor Xa (FXa) inhibitor, and a TAFIa inhibitor, potato tuber carboxypeptidase inhibitor (PCI) on tissue-type plasminogen activator (t-PA)-induced clot lysis in human plasma in vitro. Pooled human plasma (containing 180 ng/mL t-PA and 0.1 nM thrombomodulin) was mixed with edoxaban and/or PCI. Clot formation was induced by 2.5 pM tissue factor and 4 µM phospholipids and clot lysis time was examined. Plasma plasmin-α2 antiplasmin complex (PAP) concentration was measured as a marker of plasmin generation. Edoxaban or PCI alone significantly shortened the t-PA-induced clot lysis time and plasma PAP concentration. The combination of these compounds significantly accelerated the clot lysis compared with the inhibitors alone. Addition of PCI (0.3, 1, and 3 μg/mL) to 75 ng/mL edoxaban increased plasma PAP concentration compared with edoxaban alone; however, compared with PCI alone only the combination of 0.3 μg/mL PCI + 75 ng/mL edoxaban showed the significant increase in PAP concentration. Concomitant use of an oral direct FXa inhibitor, edoxaban, and a TAFIa inhibitor, PCI, significantly accelerate fibrinolysis via enhancement of plasmin generation. These results suggest that the combination of edoxaban and a TAFIa inhibitor might be beneficial for the treatment of thromboembolic diseases.
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http://dx.doi.org/10.1007/s11239-019-01929-3DOI Listing
January 2020

Responses of prothrombin time and activated partial thromboplastin time to edoxaban in Japanese patients with non-valvular atrial fibrillation: characteristics of representative reagents in Japan (CVI ARO 7).

Heart Vessels 2019 Dec 23;34(12):2011-2020. Epub 2019 May 23.

Department of Cardiovascular Medicine, The Cardiovascular Institute, 3-2-19 Nishi-azabu, Minato-ku, Tokyo, 106-0031, Japan.

The aims of this study were to determine the distribution of plasma concentration of edoxaban (PC-Ed) with their 90% interval (on therapy range) and its correlation with anticoagulation markers in patients with non-valvular atrial fibrillation (NVAF). Consecutive 97 NVAF patients under edoxaban therapy were evaluated (60/30 mg dose, n = 48/49; men/women, n = 71/26; age, 69 years). CHADS score 0, 1, and ≥ 2 were 27%, 44%, and 29%, respectively. The mean (90% interval) of PC-Ed by LC-MS/MS was 194.3 (49.4-345.3) and 17.0 (4.8-40.7) ng/mL at peak (2-4 h post-dose) and trough (pre-dose), respectively. Correlation of prothrombin time (PT) with PC-Ed was higher than that of activated partial thromboplastin time (aPTT). Among 6 PT reagents, Coagupia PT-N and Simplastin Excel S (both PT reagents) showed the highest predictive capability for the upper outlier of PC-Ed at peak and trough. Among 4 aPTT reagents, only Thrombocheck APTT measured at peak had a significant predictive capability. When using PT reagents, both peak and trough sampling showed a similar predictive capability for the upper outliers of PC-Ed with a high sensitivity, but a relatively low specificity. We demonstrated the distributions of plasma concentration, PT with 6 reagents, and aPTT with 4 reagents under edoxaban therapy in Japanese patients with NVAF, showing their 90% intervals. For predicting the upper outlier of PC-Ed, PT was more sensitive compared with aPTT, whereas predicting capability for the outliers of PC-Ed was mostly similar between peak and trough samplings among PT reagents (UMIN 000032492).
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http://dx.doi.org/10.1007/s00380-019-01438-6DOI Listing
December 2019

A direct oral anticoagulant edoxaban accelerated fibrinolysis via enhancement of plasmin generation in human plasma: dependent on thrombin-activatable fibrinolysis inhibitor.

J Thromb Thrombolysis 2019 Jul;48(1):103-110

End-Organ Disease Laboratories, Daiichi Sankyo Co., Ltd., Tokyo, Japan.

A direct oral anticoagulant, edoxaban, is as effective as vitamin K antagonists for the treatment of venous thromboembolism (VTE). However, the mechanism underlying the treatment effect on VTE remains to be determined. The aims of this study were to evaluate the effect of edoxaban on tissue plasminogen activator (t-PA)-induced clot lysis in human plasma and to determine the roles of plasmin and thrombin-activatable fibrinolysis inhibitor (TAFI) in the profibrinolytic effect by edoxaban. Pooled human normal plasma or TAFI-deficient plasma (containing 180 ng/mL t-PA and 0.1 nM thrombomodulin) was mixed with edoxaban or an activated TAFI inhibitor, potato tuber carboxypeptidase inhibitor (PCI). Clot was induced by adding tissue factor and phospholipids. Clot lysis time and plasma plasmin-α2 antiplasmin complex (PAP) concentration were determined. Clot structure was imaged with a scanning electron microscope. In normal plasma, edoxaban at clinically relevant concentrations (75, 150, and 300 ng/mL) and PCI significantly shortened clot lysis time. PCI increased PAP concentration and a correlation between PAP concentration and percent of clot lysis was observed. Edoxaban also dose-dependently elevated PAP concentration. In TAFI-deficient plasma, the effects of edoxaban and PCI on clot lysis and PAP concentration were markedly diminished as compared with normal plasma. Fibrin fibers were thinner in clots formed in the presence of edoxaban. In conclusion, edoxaban at clinically relevant concentrations accelerates t-PA-induced fibrinolysis via increasing plasmin generation in human plasma. The effects of edoxaban is mainly dependent on TAFI. The profibrinolytic effect of edoxaban might contribute to the efficacy for the treatment of VTE.
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http://dx.doi.org/10.1007/s11239-019-01851-8DOI Listing
July 2019

Sensory evaluation of edoxaban orally disintegrating tablets: an open-label interventional study (secondary publication).

Thromb J 2019 15;17. Epub 2019 Feb 15.

3Daiichi Sankyo Co., Ltd., 3-5-1, Nihonbashi Honcho, Chuo-ku, Tokyo 103-8426 Japan.

Background: This study involved a sensory evaluation of edoxaban orally disintegrating (OD) tablets in patients with nonvalvular atrial fibrillation who had been receiving the existing edoxaban film-coated tablets before the study.

Methods: Edoxaban OD tablets 30 or 60 mg were prescribed for patients who had been receiving the existing 30- or 60-mg edoxaban film-coated tablets before the study. Each dose group was randomized into groups taking the tablets with or without water. After ingestion of the edoxaban OD tablet, each patient was asked to complete a sensory evaluation questionnaire (12 items).

Results: In the evaluation of satisfaction with edoxaban OD tablets, 52.8% of the patients perceived "no difference" from the existing edoxaban film-coated tablets and 34.9% indicated that they were more satisfied with the OD tablets, thus demonstrating a relatively high degree of satisfaction. When asked about convenience and reliability in using edoxaban OD tablets, about half of the patients perceived "no difference" from the existing edoxaban film-coated tablets and the remaining half indicated preference for the OD tablets. Responses about taste, flavor, ease of ingestion, and motivation to continue taking edoxaban indicated the overall acceptance of the OD tablets. Recognition of edoxaban OD tablets was rated as "easy" by about half of the patients and "difficult" by the remaining half. Among all patients, 49.5% preferred a change to edoxaban OD tablets. The degree of satisfaction with taste, flavor, and ease of ingestion, as well as overall satisfaction, tended to be greater when the OD tablets were taken with rather than without water, and the percentage of patients who preferred a change was higher in the group taking the OD tablets with water.

Conclusions: This study indicated that the degree of satisfaction with taste, flavor, ease of ingestion, and convenience, as well as overall satisfaction, in addition to motivation to continue drug intake and sense of confidence were greater for OD tablets than for the existing edoxaban film-coated tablets. Edoxaban OD tablet is a promising formulation for inducing greater patient adherence to medication and therefore ensures better treatment response.

Trial Registration: UMIN-CTR UMIN000028788, registered 23-Aug-2017.
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http://dx.doi.org/10.1186/s12959-019-0192-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6376672PMC
February 2019

Prevention of Stent Thrombosis in Rats by a Direct Oral Factor Xa Inhibitor Edoxaban.

Pharmacology 2019 19;103(1-2):17-22. Epub 2018 Oct 19.

Rare Disease Laboratories, Daiichi Sankyo Co., Ltd., Tokyo, Japan.

Background/aims: Stent thrombosis is a serious complication after percutaneous coronary intervention and femoropopliteal endovascular intervention. The aim of this study was to determine the antithrombotic effects of a direct factor Xa inhibitor edoxaban alone or in combination with antiplatelet agents in a rat model of stent thrombosis.

Methods: Stainless steel stents (4 stents per rat) were placed in an extracorporeal arteriovenous shunt. The shunt was inserted into the carotid artery and the jugular vein in each rat to circulate blood. Stent thrombosis was induced by exposing the stents to arterial blood for 30 min. Protein content of the thrombus was measured. Edoxaban and antiplatelet agents (aspirin, clopidogrel, and ticagrelor) were orally administered before the thrombus induction.

Results: Edoxaban (0.3-3 mg/kg), clopidogrel (1-10 mg/kg), aspirin (10-100 mg/kg), and ticagrelor (0.3-3 mg/kg) exerted significant and dose-dependent antithrombotic effects in a rat stent thrombosis model. The effect of edoxaban was comparable to that of antiplatelet agents. The combination of submaximal doses of edoxaban and clopidogrel or aspirin significantly potentiated the antithrombotic effects compared with antiplatelet agents alone.

Conclusion: These results suggest that edoxaban alone and in combination with clopidogrel or aspirin are promising antithrombotic therapies for the prevention of stent thrombosis.
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http://dx.doi.org/10.1159/000494059DOI Listing
March 2019

Fibrinolytic potential of DS-1040, a novel orally available inhibitor of activated thrombin-activatable fibrinolysis inhibitor (TAFIa).

Thromb Res 2018 08 9;168:96-101. Epub 2018 Jul 9.

Rare Disease & LCM Laboratories, Daiichi Sankyo Co., Ltd., Tokyo, Japan.

An activated thrombin-activatable fibrinolysis inhibitor (TAFIa) attenuates fibrinolysis by removing C-terminal lysine/arginine residues from partially degraded fibrin. We have identified a novel low-molecular-weight inhibitor of TAFIa, DS-1040, to be potentially useful for treating thrombotic diseases. In this study, we investigated its in vitro pharmacological profile and in vivo effects in animal models of microthrombosis and bleeding. DS-1040 inhibited human TAFIa and carboxypeptidase N (CPN) in vitro with IC values of 5.92 and 3.02 × 10 nmol/L, respectively, suggesting that DS-1040 is highly selective for TAFIa over CPN. DS-1040 did not affect platelet aggregation and coagulation time. In a tissue factor-induced rat microthrombosis model, intravenously administered DS-1040 reduced existing fibrin clots in the lung, whereas post-treatment with enoxaparin had limited effect. Both intravenously and orally administered DS-1040 elevated plasma D-dimer levels with similar plasma exposures of DS-1040. DS-1040 significantly augmented plasma D-dimer level on top of silent dose of recombinant tissue-plasminogen activator (t-PA), suggesting DS-1040 enhances fibrinolytic activity of t-PA. In addition, DS-1040 did not prolong the tail bleeding time beyond its efficacy dose. These results indicate that DS-1040 is a potent, selective, intravenously/orally available inhibitor of TAFIa with minimum risk of bleeding. DS-1040 is a potential novel fibrinolysis enhancer useful in treating thrombotic diseases.
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http://dx.doi.org/10.1016/j.thromres.2018.06.010DOI Listing
August 2018

A direct oral factor Xa inhibitor edoxaban ameliorates neointimal hyperplasia following vascular injury and thrombosis in apolipoprotein E-deficient mice.

J Thromb Thrombolysis 2018 Jul;46(1):95-101

Rare Disease and LCM Laboratories, Daiichi Sankyo Co., Ltd., Tokyo, Japan.

Vascular injury activates the coagulation cascade. Some studies report that coagulation factor Xa and thrombin are implicated in proliferation of vascular smooth muscle cells and neointimal hyperplasia after vascular injury. The aim of this study was to determine the effect of an oral direct factor Xa inhibitor, edoxaban, on neointimal hyperplasia following the carotid artery injury in apolipoprotein E (ApoE)-deficient mice. Vascular injury was induced by the application of 10% ferric chloride to the carotid artery for 3 min in ApoE-deficient mice. After vascular injury, all animals were fed with high-cholesterol chow for 6 weeks. Edoxaban at 15 mg/kg was orally administered to the mice 1 h before (n = 10) or 1 h after (n = 9) ferric chloride injury, and thereafter 10 mg/kg edoxaban was orally administered b.i.d. for 6 weeks. Thrombus formation and neointimal hyperplasia were evaluated. Treatment with 15 mg/kg edoxaban before vascular injury almost completely inhibited thrombus formation, and following chronic administration of edoxaban significantly suppressed neointimal hyperplasia. In the mice treated with edoxaban after vascular injury, there was wide interindividual variability. In some mice (four out of nine) the neointimal hyperplasia was inhibited like in edoxaban-pretreated mice, but there was no statistical difference compared with control. This study demonstrated that inhibition of the coagulation and thrombosis by edoxaban ameliorated neointimal hyperplasia caused by vascular injury and high-cholesterol diets in ApoE-deficient mice. This suggests that factor Xa has a crucial role in the formation of neointima following vascular injury.The abstract should be followed by 3-4 bullet points that highlight major findings. The final bullet point should emphasize future directions for research.
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http://dx.doi.org/10.1007/s11239-018-1673-7DOI Listing
July 2018

Tissue-type plasminogen activator transgenic rats for evaluating inhibitors of the activated form of thrombin-activatable fibrinolysis inhibitor.

Blood Coagul Fibrinolysis 2018 Apr;29(3):314-321

Rare Disease & LCM Laboratories.

: No rodent models are currently available for evaluating inhibitors of the activated form of thrombin-activatable fibrinolysis inhibitor (TAFIa) without exogenous supplementation of tissue-type plasminogen activator (tPA). Characterization of tPA transgenic rats as a tool for the nonclinical evaluation of TAFIa inhibitors is the objective of the current study. tPA transgenic rats were subjected to rat models of tissue-factor-induced thromboembolism, FeCl3-induced deep vein thrombosis (DVT) and arterial thrombosis, and tail bleeding. Potato tuber carboxypeptidase inhibitor (PCI), a selective TAFIa inhibitor, was used as an experimental compound at doses of 0.1, 1, or 10 mg/kg, and its antithrombotic effects and bleeding prolongation effect were compared with nontransgenic rats. Intravenous PCI showed significant and dose-related increase in plasma D-dimer levels in the tissue-factor-induced thromboembolism model. Intravenous PCI also significantly and dose-dependently reduced thrombus weights in the two thrombosis models only in the tPA transgenic rats. These results suggest that sensitive in-vivo evaluation of TAFIa inhibitors can be achieved using tPA transgenic rats without exogenous supplementation of recombinant tPA. On the other hand, no statistically significant prolongation of bleeding times by PCI was observed in either strain, whereas increased bleeding times were observed with 10 mg/kg of intravenous recombinant tPA, suggesting that the low bleeding risk of TAFIa inhibitors is further confirmed in the tPA transgenic rats whose basal tPA levels are elevated. tPA transgenic rats may be beneficial for the pharmacological and toxicological evaluation of TAFIa inhibitors and further confirm that TAFIa is a promising target for various thrombotic disorders.
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http://dx.doi.org/10.1097/MBC.0000000000000723DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5943070PMC
April 2018

Correction to: Generation and characterization of tissue-type plasminogen activator transgenic rats.

J Thromb Thrombolysis 2018 Jan;45(1):88

Rare Disease & LCM Laboratories, Daiichi Sankyo Co., Ltd., 1-2-58 Hiromachi, Shinagawa-ku, Tokyo, 140-8710, Japan.

In the original publication of the article, the sentence in "Result" section have been incorrectly published as: "Three lines of tPA Tg rats were generated and analyzed by Southern blotting to confirm the presence of the transgene in genomic DNA. When rat DNA was digested with EcoRI and hybridized to the tPA probe described in "Materials and methods", a 1.0 kb band was detected (Fig. 1a, b). One founder line was selected because of its high copy number (about ten copies) of tPA gene and itansgene) and 4.4 kb (endogenous gene) reding appearance, body weight, hematology, and systematization." The corrected sentence should read as: "Three lines of tPA Tg rats were generated and analyzed by Southern blotting to confirm the presence of the transgene in genomic DNA. When rat DNA was digested with EcoRI and hybridized to the tPA probe described in "Materials and methods", a 1.0 kb band was detected (Fig. 1a, b). One founder line was selected because of its high copy number (about ten copies) of tPA gene and its lack of detectable abnormal findings, including appearance, body weight, hematology, and systematization." The original article has been corrected.
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http://dx.doi.org/10.1007/s11239-017-1598-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5756270PMC
January 2018

Generation and characterization of tissue-type plasminogen activator transgenic rats.

J Thromb Thrombolysis 2018 Jan;45(1):77-87

Rare Disease & LCM Laboratories, Daiichi Sankyo Co., Ltd., 1-2-58 Hiromachi, Shinagawa-ku, Tokyo, 140-8710, Japan.

To address a species difference in the responsiveness to human recombinant tissue-type plasminogen activator (rt-PA) between rats and humans, tPA transgenic (Tg) rats were generated and characterized. In the rats, transcriptional regulation of tPA was designed under the control of the endogenous tPA promoter. There were no significant differences in hematological parameters between the tPA Tg and non Tg rats. Plasma tPA concentration was significantly increased and serum free PAI-1 was significantly decreased in the tPA Tg rats. Significant overexpression of tPA mRNA in five major organs was also confirmed in the tPA Tg rats. In contrast, the extent of tPA mRNA induction by pathophysiological stimuli (focal cerebral ischemia) was comparable in the two strains. Earlier increase in the plasma D-Dimer level was observed in the tPA Tg rats in a model of thromboembolism compared with the non Tg rats. On the other hand, there was no statistically significant prolongation of bleeding time in a rat model of bleeding between the two strains. rt-PA showed dose-related blood flow restoration in a rat model of thromboembolic stroke in the tPA Tg rats from a dose (1 mg/kg, i.v.) similar to clinical doses for human stroke patients. In conclusion, tPA Tg rats, in which tPA is overexpressed and endogenous fibrinolytic activity is enhanced without hemostatic abnormality, were generated. tPA Tg rats would be beneficial for the pharmacological and the toxicological evaluation of rt-PA and other various fibrinolytic enhancers.
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http://dx.doi.org/10.1007/s11239-017-1582-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5756269PMC
January 2018

Tranexamic Acid Failed to Reverse the Anticoagulant Effect and Bleeding by an Oral Direct Factor Xa Inhibitor Edoxaban.

Pharmacology 2018 3;101(1-2):92-95. Epub 2017 Nov 3.

Department of Medical Science, Tokyo, Japan.

Background/aims: Agents to reverse the anticoagulant effect of edoxaban, an oral direct factor Xa inhibitor, would be desirable in emergency situations. The aim of this study is to determine the effect of tranexamic acid, an antifibrinolytic agent, on the anticoagulant activity and bleeding by edoxaban in rats.

Methods: A supratherapeutic dose of edoxaban (3 mg/kg) was intravenously administered to rats. Three minutes after dosing, tranexamic acid (100 mg/kg) was given intravenously. Bleeding was induced by making an incision with a blade on the planta 8 min after edoxaban injection and bleeding time was measured. Prothrombin time (PT) and clot lysis were examined.

Results: A supratherapeutic dose of edoxaban significantly prolonged PT and bleeding time. Tranexamic acid did not affect PT or bleeding time prolonged by edoxaban, although tranexamic acid significantly inhibited clot lysis in rat plasma.

Conclusion: An antifibrinolytic agent tranexamic acid failed to reverse the anticoagulant effect and bleeding by edoxaban in rats.
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http://dx.doi.org/10.1159/000484172DOI Listing
August 2018

Increased risk of SSEs in bone-only metastatic breast cancer patients treated with zoledronic acid.

J Bone Oncol 2017 Sep 31;8:18-22. Epub 2017 Aug 31.

Division of Pharmacotherapy, Kindai University Faculty of Pharmacy, 3-4-1 Kowakae, Higashi-Osaka, Osaka, Japan.

Background: Bone represents one of the most common sites to which breast cancer cells metastasize. Patients experience skeletal related adverse events (pathological fractures, spinal cord compressions, and irradiation for deteriorated pain on bone) even during treatment with zoledronic acid (ZA). Therefore, we conducted a retrospective cohort study to investigate the predictive factors for symptomatic skeletal events (SSEs) in bone-metastasized breast cancer (b-MBC) patients.

Methods: We retrospectively collected data on b-MBC patients treated with ZA. Patient characteristics, including age, subtype, the presence of non-bone lesions, the presence of multiple bone metastases at the commencement of ZA therapy, duration of ZA therapy, the time interval between breast cancer diagnosis and the initiation of ZA therapy, and type of systemic therapy, presence of previous SSE were analyzed using multivariable logistic regression analysis.

Results: The medical records of 183 patients were reviewed and 176 eligible patients were analyzed. The median age was 59 (range, 30-87) years. Eighty-seven patients were aged ≥60 years and 89 patients were aged < 60 years. The proportions of patients with estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2-positive disease were 81.8%, 63.1%, and 17.6%, respectively. Fifty-three patients had bone-only MBC at the commencement of ZA therapy. SSEs were observed in 42 patients. In the multivariable logistic regression analysis, bone-only MBC but not a breast cancer subtype was an independent risk factor for an SSE during ZA therapy (odds ratio: 3.878, 95% confidence interval: 1.647-9.481; p = 0.002).

Conclusions: Bone-only MBC patients are more likely to experience an SSE even after treatment with ZA.
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http://dx.doi.org/10.1016/j.jbo.2017.08.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5581372PMC
September 2017

Prevention of arterial thrombosis by edoxaban, an oral factor Xa inhibitor in rats: monotherapy and in combination with antiplatelet agents.

Eur J Pharmacol 2016 Sep 7;786:246-252. Epub 2016 Jun 7.

Biological Research Laboratories, R & D Division, Daiichi Sankyo Co., Ltd, Tokyo, Japan. Electronic address:

In addition to platelet aggregation, coagulation activation is considered to be involved in arterial thrombosis. In this study, we determined antithrombotic effects of edoxaban, an oral factor Xa (FXa) inhibitor, as both a monotherapy and in combination with antiplatelet agents in a rat model of arterial thrombosis. We further examined its effects on a procoagulant biomarker and bleeding. Arterial thrombosis was induced by topical application of 15% ferric chloride to rat abdominal aortas. Bleeding time was measured by a tail incision method. Edoxaban, clopidogrel, and aspirin were orally administered 30min, 4h, and 2h before thrombus or bleeding induction. As a biomarker of coagulation activation, plasma thrombin-antithrombin complex (TAT) was measured. Edoxaban dose-dependently prevented arterial thrombosis in a manner comparable to clopidogrel and aspirin. The combination of edoxaban plus clopidogrel or edoxaban plus aspirin significantly potentiated the antithrombotic effects compared with these drugs alone. The combination of edoxaban and clopidogrel was more potent than clopidogrel and aspirin. Plasma TAT concentration was elevated after thrombus induction and suppressed by edoxaban and clopidogrel, but not by aspirin, suggesting P2Y12 receptor-mediated platelet procoagulant activity. Bleeding time was prolonged by the coadministration of edoxaban and clopidogrel, but not by edoxaban and aspirin. In conclusion, the present study demonstrates that the monotherapy with edoxaban and combination therapy with edoxaban plus clopidogrel or edoxaban plus aspirin are promising options for the prevention of arterial thrombosis as effective as the standard antiplatelet agents; however, a combination of edoxaban and clopidogrel increased the risk of bleeding.
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http://dx.doi.org/10.1016/j.ejphar.2016.06.011DOI Listing
September 2016

A direct thrombin inhibitor suppresses protein C activation and factor Va degradation in human plasma: Possible mechanisms of paradoxical enhancement of thrombin generation.

Thromb Res 2016 May 3;141:77-83. Epub 2016 Mar 3.

Biological Research Laboratories, R&D Division, Daiichi Sankyo Co., Ltd., 1-2-58 Hiromachi, Shinagawa-ku, Tokyo 140-8710, Japan. Electronic address:

We have demonstrated that antithrombin (AT)-independent thrombin inhibitors paradoxically increase thrombin generation (TG) in human plasma in a thrombomodulin (TM)- and protein C (PC)-dependent manner. We determined the effects of AT-independent thrombin inhibitors on the negative-feedback system, activation of PC and production and degradation of factor Va (FVa), as possible mechanisms underlying the paradoxical enhancement of TG. TG in human plasma containing 10nM TM was assayed by means of the calibrated automated thrombography. As an index of PC activation, plasma concentration of activated PC-PC inhibitor complex (aPC-PCI) was measured. The amounts of FVa heavy chain and its degradation product (FVa(307-506)) were examined by western blotting. AT-independent thrombin inhibitors, melagatran and dabigatran (both at 25-600nM) and 3-30μg/ml active site-blocked thrombin (IIai), increased peak levels of TG. Melagatran, dabigatran and IIai significantly decreased plasma concentration of aPC-PCI complex at 25nM or more, 75nM or more, and 10 and 30μg/ml, respectively. Melagatran (300nM) significantly increased FVa and decreased FVa(307-506). In contrast, a direct factor Xa inhibitor edoxaban preferentially inhibited thrombin generation (≥25nM), and higher concentrations were required to inhibit PC activation (≥150nM) and FVa degradation (300nM). The present study suggests that the inhibitions of protein C activation and subsequent degradation of FVa and increase in FVa by antithrombin-independent thrombin inhibitors may contribute to the paradoxical TG enhancement, and edoxaban may inhibit PC activation and FVa degradation as a result of TG suppression.
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http://dx.doi.org/10.1016/j.thromres.2016.03.005DOI Listing
May 2016

Edoxaban, a direct factor Xa inhibitor, suppresses tissue-factor induced human platelet aggregation and clot-bound factor Xa in vitro: Comparison with an antithrombin-dependent factor Xa inhibitor, fondaparinux.

Thromb Res 2016 May 26;141:17-21. Epub 2016 Feb 26.

Biological Research Laboratories, R & D Division, Daiichi Sankyo Co., Ltd, Tokyo, Japan. Electronic address:

Introduction: Tissue factor-induced platelet aggregation and factor Xa (FXa) activity bound to clot contribute to the formation and growth of thrombus. The effects of edoxaban, a direct FXa inhibitor, on these responses were determined and compared with that of fondaparinux, an antithrombin-dependent (indirect) FXa inhibitor.

Material And Methods: Human platelet aggregation was induced by human tissue factor (Dade Innovin or RecombiPlasTin) in platelet-rich plasma spiked with edoxaban or fondaparinux. Clot formed from human whole blood was incubated with 0.9μM prothrombin in the absence or presence of FXa inhibitors. As the index of FXa activity, the amount of prothrombin fragment F1+2 was measured with an ELISA. Free FXa activity was measured using human FXa and its chromogenic substrate S-2222.

Results: Edoxaban inhibited tissue factor-induced platelet aggregation in a concentration-dependent manner with the IC50 values of 150 and 110nM for Dade Innovin and RecombiPlasTin-induced platelet aggregation, respectively. At 1μM, edoxaban completely inhibited the aggregation. Fondaparinux inhibited RecombiPlasTin-induced aggregation with the IC50 of 9.3μM, but did not show complete inhibition up to 30μM and had no effect on Dade Innovin-induced aggregation. Edoxaban inhibited both free and clot-bound FXa with the IC50 of 2.3 and 8.2nM, respectively. Fondaparinux inhibited free FXa (IC50 5.4nM), but 40-times higher concentration were required to inhibit clot-bound FXa (IC50 217nM).

Conclusions: Edoxaban, a direct FXa inhibitor, was a more potent inhibitor of tissue factor-induced platelet aggregation and clot-bound FXa than fondaparinux, an indirect FXa inhibitor.
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http://dx.doi.org/10.1016/j.thromres.2016.02.028DOI Listing
May 2016

Paradoxical enhancement of the intrinsic pathway-induced thrombin generation in human plasma by melagatran, a direct thrombin inhibitor, but not edoxaban, a direct factor Xa inhibitor, or heparin.

Thromb Res 2015 Sep 4;136(3):658-62. Epub 2015 Jul 4.

Biological Research Laboratories, R&D Division, Daiichi Sankyo Co., Ltd., 1-2-58 Hiromachi, Shinagawa-ku, Tokyo 140-8710, Japan.

Introduction: The blood coagulation cascade consists of two pathways, the tissue factor (TF)-dependent extrinsic pathway and the contact factor-dependent intrinsic pathway. We have previously shown that a direct thrombin inhibitor, melagatran, paradoxically increased TF-induced thrombin generation (TG) in thrombomodulin (TM)-containing human plasma in vitro. However, the effect of melagatran on the intrinsic pathway-induced TG remains to be investigated. We investigated whether melagatran enhances the intrinsic pathway-induced TG.

Methods And Results: TG was induced by kaolin in human plasma and assayed by the calibrated automated thrombography method. Melagatran at 150 and 300 nM significantly increased the peak level (2.40-fold) and endogenous thrombin potential of TG in normal plasma in the presence of 5 nM TM. In the absence of TM or in protein C (PC)-deficient plasma, the paradoxical enhancement of TG by melagatran disappeared. A direct FXa inhibitor, edoxaban, and an antithrombin-dependent anticoagulant, unfractionated heparin (UFH), did not increase, but simply decreased TG under each condition in a concentration dependent manner.

Conclusion: Melagatran enhanced the intrinsic pathway-induced TG as well as the extrinsic pathway-induced TG in human plasma under the condition where PC system is active. In contrast, edoxaban and UFH showed concentration-dependent decrease of TG, but no enhancement. These results indicated that edoxaban and UFH may have a low risk of the paradoxical enhancement of TG by both the extrinsic and intrinsic pathway activation.
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http://dx.doi.org/10.1016/j.thromres.2015.06.034DOI Listing
September 2015

Thrombin generation induced by tissue factor plus ADP in human platelet rich plasma: A potential new measurement to assess the effect of the concomitant use of an oral factor Xa inhibitor edoxaban and P2Y12 receptor antagonists.

Thromb Res 2015 May 9;135(5):958-62. Epub 2015 Mar 9.

Biological Research Laboratories, R & D Division, Daiichi Sankyo Co., Ltd, Tokyo, Japan. Electronic address:

Introduction: Patients with atrial fibrillation undergoing percutaneous coronary intervention may require combination therapy with anticoagulants and antiplatelet agents. The objectives of this study were to establish an assay which can evaluate the effects of both anticoagulants and P2Y12 receptor antagonists and determine the effects of edoxaban, a direct factor Xa inhibitor, and P2Y12 receptor antagonists (clopidogrel and ticagrelor) alone and when combined.

Material And Methods: Human platelet-rich plasma (PRP) from healthy subjects was stimulated with adenosine diphosphate (ADP) plus tissue factor. Thrombin generation was measured by means of calibrated automated thrombography.

Results: Combination of 10μM ADP and low concentration (0.25 pM) tissue factor induced reproducible thrombin generation in human PRP. Edoxaban (40 and 80ng/mL), active metabolite of clopidogrel (AM-clopidogrel, 10 and 20μg/mL), and ticagrelor (3μg/mL) alone inhibited ADP plus tissue factor-induced thrombin generation. Edoxaban suppressed all 5 parameters (lag time, peak, time to peak, endogenous thrombin potential, and maximum rate), whereas AM-clopidogrel and ticagrelor inhibited 4 and 3 parameters, respectively. Concomitant treatment with edoxaban and AM-clopidogrel or ticagrelor produced an additive inhibition of thrombin generation compared to the single treatments.

Conclusions: The thrombin generation assay induced by ADP plus tissue factor can detect the activities of both edoxaban and P2Y12 receptor antagonists. Combination of edoxaban and a P2Y12 receptor antagonist shows additive inhibition. These results suggest that ADP plus tissue factor-induced thrombin generation may be a useful measurement to assess the combination effects of anticoagulants and P2Y12 receptor antagonists in a single assay.
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http://dx.doi.org/10.1016/j.thromres.2015.03.001DOI Listing
May 2015

Laboratory measurements of the oral direct factor Xa inhibitor edoxaban: comparison of prothrombin time, activated partial thromboplastin time, and thrombin generation assay.

Am J Clin Pathol 2015 Feb;143(2):241-7

From Biological Research Laboratories, R &D Division, Daiichi Sankyo, Tokyo, Japan.

Objectives: Edoxaban, an oral direct factor Xa inhibitor, does not require routine monitoring. However, assessment of the anticoagulant effects may be required in certain situations.

Methods: We investigated the effects of edoxaban on prothrombin time (PT), activated partial thromboplastin time (aPTT), and thrombin generation using human platelet-poor plasma (PPP) or platelet-rich plasma (PRP).

Results: Edoxaban concentration-dependently prolonged PT and aPTT. There was a considerable variation in the magnitude of PT prolongation among the reagents used. The variability in aPTT prolongation among the reagents was smaller than that of PT. Edoxaban concentration-dependently inhibited thrombin generation, with a more potent effect seen in PPP than in PRP. Thrombin generation assay was three times more sensitive to edoxaban than PT and aPTT.

Conclusions: PT had disadvantages of a large variability among different PT reagents. aPTT could be used as a conventional and convenient test with a smaller variation among reagents. Thrombin generation was the most sensitive assay.
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http://dx.doi.org/10.1309/AJCPQ2NJD3PXFTUGDOI Listing
February 2015

Effective reversal of edoxaban-associated bleeding with four-factor prothrombin complex concentrate in a rabbit model of acute hemorrhage.

Anesthesiology 2015 Feb;122(2):387-98

From Preclinical Research and Development, CSL Behring GmbH, Marburg, Germany (E.H., F.K., W.K., B.D., J.M-C., I.P., G.D.); and Biological Research Laboratories, R&D Division, Daiichi Sankyo Co., Ltd., Tokyo, Japan (Y.M.).

Background: Edoxaban is an oral, selective direct factor Xa inhibitor approved in Japan for venous thromboembolism prevention after orthopedic surgery. Data are lacking regarding reversal strategies for edoxaban; this study assessed whether four-factor prothrombin complex concentrate (Beriplex/Kcentra; CSL Behring GmbH, Marburg, Germany) can effectively reverse its effects on hemostasis using a previously described rabbit model.

Methods: The study comprised assessments of thrombin generation in vitro, pharmacokinetic parameters, and edoxaban reversal in vivo. In a blinded in vivo stage, a standardized kidney incision was performed in animals (n = 11 per group) randomized to receive vehicle + saline, edoxaban (1,200 μg/kg) + saline, or edoxaban (1,200 μg/kg) + four-factor prothrombin complex concentrate (50 IU/kg). Animals were monitored for treatment impact on hemostasis and coagulation parameters. Data are median (range). Statistical tests were adjusted for multiple testing.

Results: Edoxaban administration increased blood loss (30 [2 to 44] ml) and time to hemostasis (23 [8.5 to 30.0] min) compared with the control group (3 [1 to 8] ml and 3 [2.0 to 5.0] min, respectively). Biomarkers of coagulation (prothrombin time, activated partial thromboplastin time, whole blood clotting time) and thrombin generation parameters (e.g., peak thrombin, endogenous thrombin potential, lag time) were also affected by edoxaban. Administration of four-factor prothrombin complex concentrate significantly reduced time to hemostasis (to 8 [6.5 to 14.0] min, observed P < 0.0001) and total blood loss (to 9 [4 to 22] ml, observed P = 0.0050) compared with the edoxaban + saline group. Of the biomarkers tested, prothrombin time, whole blood clotting time, and endogenous thrombin potential correlated best with clinical parameters.

Conclusion: In a rabbit model of hemostasis, four-factor prothrombin complex concentrate administration significantly decreased edoxaban-associated hemorrhage.
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http://dx.doi.org/10.1097/ALN.0000000000000520DOI Listing
February 2015

Treatment of venous thrombosis with an oral direct factor Xa inhibitor edoxaban by single and multiple administrations in rats.

Eur J Pharmacol 2014 Nov 30;742:15-21. Epub 2014 Aug 30.

Biological Research Laboratories, R & D Division, Daiichi Sankyo Co., Ltd., 1-2-58 Hiromachi, Shinagawa-ku, Tokyo 140-8710, Japan.

Edoxaban is an oral and direct activated factor X inhibitor. In this study, the acute treatment effect of edoxaban on venous thrombosis is investigated in rats by single and multiple administrations, and compared to the conventional parenteral anticoagulants, enoxaparin and fondaparinux. Venous thrombus was induced in the inferior vena cava by partial stenosis plus topical application of 10% ferric chloride for 5min. After 1-h thrombus maturation, oral edoxaban and subcutaneous enoxaparin and fondaparinux were given. In the single administration experiment, thrombus weight was measured 1 or 4h after thrombus induction. In the multiple administration experiments, edoxaban was orally administered once daily (QD) and twice daily (BID) for 3 days. In the single administration experiment, oral administration of edoxaban (3.0 and 10mg/kg) 1h after thrombus formation significantly regressed the venous thrombus compared to the thrombus at 1h after thrombus formation. Similarly the significant venous thrombus regression was observed with enoxaparin (10mg/kg) and fondaparinux (0.30-3.0mg/kg). In the multiple administration experiment, both QD and BID administration of edoxaban at daily doses of 5 and 10mg/kg exerted significant treatment effects. QD administration of edoxaban including lower doses (1-10mg/kg) significantly reduced thrombus weight. Edoxaban administered QD and BID was effective in the treatment of venous thrombosis, and the treatment effect of edoxaban was comparable to the conventional parenteral anticoagulants. These data demonstrate the potential of edoxaban as an oral anticoagulant in the acute treatment of venous thromboembolism.
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http://dx.doi.org/10.1016/j.ejphar.2014.08.020DOI Listing
November 2014

Impact of nonsynonymous mutations of factor X on the functions of factor X and anticoagulant activity of edoxaban.

Blood Coagul Fibrinolysis 2015 Mar;26(2):117-22

aThe Keio-Daiichi Project on Genetics of Thrombosis, Keio University bBiological Research Laboratories cNew Drug Regulatory Affairs Department dResearch Oversight Function, R&D Division, Daiichi Sankyo Co., Ltd eLaboratory Medicine, Keio University School of Medicine, Tokyo, Japan.

Edoxaban is an oral direct factor Xa (FXa) inhibitor and its efficacy as an oral anticoagulant is less subject to drug-food and drug-drug interaction than existing vitamin K antagonists. Although this profile of edoxaban suggests it is well suited for clinical use, it is not clear whether genetic variations of factor X influence the activity of edoxaban. Our aim was to investigate a possible impact of single-nucleotide polymorphisms (SNPs) in the factor X gene on the functions of factor X and the activity of edoxaban. Two nonsynonymous SNPs within mature factor X, Ala152Thr and Gly192Arg, were selected as possible candidates that might affect the functions of FXa and the activity of edoxaban. We measured catalytic activities of wild type and mutant FXas in a chromogenic assay using S-2222 and coagulation times including prothrombin time (PT) and activated partial thrombin time (aPTT) of plasma-containing recombinant FXs in the presence and absence of edoxaban. Michaelis-Menten kinetic parameters of FXas, Km and Vmax values, PT and aPTT were not influenced by either mutation indicating these mutations do not affect the FXa catalytic and coagulation activities. The Ki values of edoxaban for the FXas and the concentrations of edoxaban required to double PT and aPTT were not different between wild type and mutated FXas indicating that both mutations have little impact on the activity of edoxaban. In conclusion, these data suggest that edoxaban has little interpatient variability stemming from SNPs in the factor X gene.
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http://dx.doi.org/10.1097/MBC.0000000000000147DOI Listing
March 2015

Comparison of the effect of edoxaban, a direct factor Xa inhibitor, with a direct thrombin inhibitor, melagatran, and heparin on intracerebral hemorrhage induced by collagenase in rats.

Thromb Res 2014 Apr 6;133(4):622-8. Epub 2013 Aug 6.

R&D Planning Department, R&D Division, Daiichi Sankyo Co., Ltd., Japan.

Introduction: Intracerebral hemorrhage (ICH) is a major clinical concern with anticoagulation therapy. The effect of a new oral direct FXa inhibitor, edoxaban, was determined in a rat model of ICH and compared with a direct thrombin inhibitor, melagatran, and heparin.

Methods: To induce ICH, 0.1 U collagenase type VII was injected into the striatum of male Wistar rats under anesthesia with thiopental or halothane. Immediately after ICH induction, edoxaban, melagatran, or heparin were infused intravenously. Five hours after ICH induction, the brain was removed and ICH size was measured. To estimate the margin of safety, antithrombotic effects were evaluated in a rat venous thrombosis model.

Results: Edoxaban at 6mg/kg/h significantly increased ICH volume (1.8-fold) and prolonged prothrombin time (PT) 2.8-fold compared to the vehicle group. No deaths were observed with edoxaban. Melagatran at 1mg/kg/h increased ICH volume at 1mg/kg/h (2.8-fold) with 6.1-fold PT prolongation. At 3mg/kg/h, all rats died due to severe ICH (3.9-fold). Heparin at both 100 and 500U/kg/h significantly increased ICH. At 500U/kg/h, 5 out of 8 rats died. The doses required for 50% inhibition of thrombosis of edoxaban, melagatran, and heparin were 0.045mg/kg/h, 0.14mg/kg/h, and 55U/kg/h, respectively. The safety margins between antithrombotic and ICH exacerbation effects of these anticoagulants were 133, 7.1, and 1.8, respectively.

Conclusion: The safety margin of edoxaban was wider than that of melagatran or heparin. These results suggest that edoxaban may be preferable from the perspective of ICH exacerbation risk.
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http://dx.doi.org/10.1016/j.thromres.2013.07.015DOI Listing
April 2014

Comparison of antithrombotic and hemorrhagic effects of edoxaban, a novel factor Xa inhibitor, with unfractionated heparin, dalteparin, lepirudin and warfarin in rats.

Thromb Res 2013 Aug 12;132(2):234-9. Epub 2013 Jun 12.

Biological Research Laboratories, R & D Division, Daiichi Sankyo Co., Ltd. Electronic address:

Background: Edoxaban is a novel, potent and orally active direct Factor Xa (FXa) inhibitor under development for prophylaxis and treatment of thromboembolic diseases. Properties of dose response and margin of safety of anticoagulants are the key factors for a positive risk/benefit of novel oral anticoagulants.

Objectives: To compare the dose response of antithrombotic effect and margin of safety between antithrombotic and hemorrhagic effects of edoxaban with conventional anticoagulants, unfractionated heparin (UFH), dalteparin (low molecular weight heparin), lepirudin, and warfarin in rat models of thrombosis and hemorrhage.

Methods: Rats were treated with edoxaban, UFH, dalteparin, and lepirudin by continuous intravenous (iv) infusion, or with oral warfarin for 4 days before inducing thrombosis or bleeding. Thrombosis was induced by inserting a platinum wire into the inferior vena cava for 60 minutes. Tail template bleeding time was measured after making an incision on the tail.

Results: In rats, iv infusion of edoxaban inhibited venous thrombosis in a dose-dependent manner. The other anticoagulants also exerted dose-dependent antithrombotic effects. The slopes of the dose-response curves of edoxaban were significantly shallower than the slopes of UFH, dalteparin, and warfarin. At supratherapeutic doses, edoxaban prolonged bleeding time in a rat tail bleeding model. To determine bleeding risk, the margins between antithrombotic and bleeding-time prolongation were compared. The margins of safety of edoxaban were wider than those of UFH, dalteparin, lepirudin, and warfarin.

Conclusions: These results suggest that edoxaban may be more easily controlled and has the potential for a more positive risk/benefit ratio compared to conventional anticoagulants.
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http://dx.doi.org/10.1016/j.thromres.2013.05.020DOI Listing
August 2013

Impact of antithrombin deficiency on efficacy of edoxaban and antithrombin-dependent anticoagulants, fondaparinux, enoxaparin, and heparin.

Thromb Res 2013 Jun 11;131(6):540-6. Epub 2013 May 11.

Biological Research Laboratories, R&D Division, Daiichi Sankyo Co., Ltd., 1-2-58 Hiromachi, Shinagawa-ku, Tokyo 140-8710, Japan.

Introduction: Oral factor Xa (FXa) inhibitors are a novel class of anticoagulants that, unlike heparins, are expected to demonstrate antithrombotic effects independent of plasma antithrombin (AT) concentrations. We utilized heterozygous AT-deficient (AT+/-) mice to determine the impact of AT deficiency on anticoagulant and antithrombotic effects of edoxaban, a direct FXa inhibitor, and compared with heparins (fondaparinux, enoxaparin, and unfractionated heparin [UHF]).

Materials And Methods: The effects of edoxaban and heparins on in vitro prothrombin time and activated partial thromboplastin time were measured in plasma obtained from wild type (AT+/+) and AT+/- male mice. To assess the antithrombotic effects of these anticoagulants in vivo, venous thrombosis was induced in the inferior vena cava by FeCl3 treatment. Potency ratios of antithrombotic effects in AT+/- compared with AT+/+ mice were analyzed by a parallel line assay.

Results: In vitro studies demonstrated that the clotting-time prolongation effects of edoxaban were not affected by heterozygous AT deficiency whereas those of AT-dependent anticoagulants were attenuated. In AT+/- mice, the antithrombotic effects of AT-dependent anticoagulants were less potent than those in AT+/+ mice. In contrast, edoxaban was equipotent in preventing thrombus formation in both wild-type and AT-deficient mice. The attenuated antithrombotic effects of fondaparinux, enoxaparin, and UFH in AT-deficient mice were restored by AT supplementation. Edoxaban exerts a comparable antithrombotic effect even in mice with low plasma AT antigen and activity to that in wild-type mice.

Conclusion: Edoxaban may potentially be prioritized over AT-dependent anticoagulants in patients with lower plasma AT concentration.
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http://dx.doi.org/10.1016/j.thromres.2013.04.016DOI Listing
June 2013

[TDM management system for contribution to proper use of anti-mRSA drugs--establishment of cooperation support system between pharmacy and clinical laboratory in hospital].

Rinsho Byori 2013 Feb;61(2):127-34

Department of Pharmacy, Kinki University Hospital, Faculty of Medicine, Osaka-Sayama 589-8511, Japan.

In team medicine, highly specialized pharmacists have recently been in demand. As one of the specialties, there is therapeutic drug monitoring (TDM). It is important for the optimal dosing of a wide range of drugs. In our hospital, a TDM service was started in 1987 at the clinical laboratory. A clinical laboratory technologist with the license of a pharmacist has performed administration plans for anti-methicillin-resistant Staphylococcus aureus (MRSA) drugs, vancomycin, teicoplanin, and arbekacin. In particular, the pharmacist in charge of TDM services, a TDM-specialized pharmacist, plays a central role in administration plans for anti MRSA drugs. Furthermore, we examined the active use of the TDM service to expand pharmaceutical care. Therefore, at first, we have worked in partnership with the clinical laboratory, as it is called the "Cooperation Support System", since September 2010. As a result, after the introduction of this system, from August 2011 to July 2012, the rate that the doctor referred to the administration plan was markedly improved by approximately 90%. We have been able to enhance TDM in practical training for pharmacology as an extension of this system. We thought that drug therapy can be performed more appropriately by increasing the number of executions of TDM in the future. For drug therapy to be done more appropriately, efforts made through cooperation with the clinical laboratory are essential for an effective TDM system. Naturally, an effective TDM process requires a collaborative, multidisciplinary approach with input from doctors, nurses, and clinical pharmacists.
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February 2013