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Abstract
New oral anticoagulants (NOAC) are the latest addition to anticoagulant armamentarium. Unlike traditional anti-coagulants like warfarin, lab monitoring and management of bleeding complications secondary to these agents is different. As more and more patients are being switched to these drugs, interventional radiologists in particular will benefit from a clinical review of NOAC.
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Affiliation(s)
- Sandeep T Laroia
- Deaprtment of Radiology, University of Iowa Hospitals and Clinic, Iowa City, Iowa, USA
| | - Steven Morales
- Deaprtment of Radiology, University of Iowa Hospitals and Clinic, Iowa City, Iowa, USA
| | - Archana T Laroia
- Deaprtment of Radiology, University of Iowa Hospitals and Clinic, Iowa City, Iowa, USA
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2
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Brix K, McInnes J, Al-Hashimi A, Rehders M, Tamhane T, Haugen MH. Proteolysis mediated by cysteine cathepsins and legumain-recent advances and cell biological challenges. PROTOPLASMA 2015; 252:755-774. [PMID: 25398648 DOI: 10.1007/s00709-014-0730-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 11/04/2014] [Indexed: 06/04/2023]
Abstract
Proteases play essential roles in protein degradation, protein processing, and extracellular matrix remodeling in all cell types and tissues. They are also involved in protein turnover for maintenance of homeostasis and protein activation or inactivation for cell signaling. Proteases range in function and specificity, with some performing distinct substrate cleavages, while others accomplish proteolysis of a wide range of substrates. As such, different cell types use specialized molecular mechanisms to regulate the localization of proteases and their function within the compartments to which they are destined. Here, we focus on the cysteine family of cathepsin proteases and legumain, which act predominately within the endo-lysosomal pathway. In particular, recent knowledge on cysteine cathepsins and their primary regulator legumain is scrutinized in terms of their trafficking to endo-lysosomal compartments and other less recognized cellular locations. We further explore the mechanisms that regulate these processes and point to pathological cases which arise from detours taken by these proteases. Moreover, the emerging biological roles of specific forms and variants of cysteine cathepsins and legumain are discussed. These may be decisive, pathogenic, or even deadly when localizing to unusual cellular compartments in their enzymatically active form, because they may exert unexpected effects by alternative substrate cleavage. Hence, we propose future perspectives for addressing the actions of cysteine cathepsins and legumain as well as their specific forms and variants. The increasing knowledge in non-canonical aspects of cysteine cathepsin- and legumain-mediated proteolysis may prove valuable for developing new strategies to utilize these versatile proteases in therapeutic approaches.
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Affiliation(s)
- Klaudia Brix
- Research Area HEALTH, Research Center MOLIFE-Molecular Life Sciences, Jacobs University Bremen, Campus Ring 1, 28759, Bremen, Germany,
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3
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Abstract
Investigation of inhibitory effect of two single-stranded DNA thrombin-inhibiting aptamers (15TBA and 31TBA) on fibrin polymerization in fibrinogen solutions and comparison of anticoagulant properties of these aptamers by a new global coagulation test of thrombodynamics. Measurement of aptamers' functional stability in human plasma and blood in vitro in order to investigate the involvement of 3'-exonuclease in fast decrease of aptamers' functional activity in vivo. Thrombin inhibition activity was measured in a buffer system in vitro as effects of aptamers on fibrin polymerization. Anticoagulant activity was investigated by measuring the spatial clot growth rate in the presence of aptamers. The stability of aptamers during incubation in human plasma was investigated in vitro by measuring activated partial thromboplastin time. Both aptamers dose-dependently inhibit fibrin polymerization in a buffer solution (IC50=10 nm for 15TBA and 3 nm for 31TBA) and are effective anticoagulants in human plasma (IC50 for spatial clot growth rate decreasing are 9.5 μmol/l and 4.0 μmol/l for 15TBA and 31TBA, correspondingly). Both aptamers remain stable in plasma or whole blood in vitro for at least 4 h. It was shown that 31TBA was 2-3 times more effective than 15TBA. Both aptamers were stable in human plasma and whole blood in vitro. So, the 3'-exonuclease could not be the reason for fast decrease of aptamers' functional activity in vivo. The main role in the removal of oligonucleotides from the circulation is played obviously by the liver.
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4
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Abstract
Quinoxalinone and its derivatives are used in organic synthesis for building natural and designed synthetic compounds and they have been frequently utilized as suitable skeletons for the design of biologically active compound. This review covers updated information on the most active quinoxalinone derivatives that have been reported to show considerable pharmacological actions such as antimicrobial, anti-inflammatory, antidiabetic, antiviral, antitumor, and antitubercular activity. It can act as an important tool for chemists to develop newer quinoxalinone derivatives that may prove to be better agents in terms of efficacy and safety.
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6
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Harenberg J, Marx S, Krejczy M, Wehling M. New anticoagulants - promising and failed developments. Br J Pharmacol 2012; 165:363-72. [PMID: 21740405 DOI: 10.1111/j.1476-5381.2011.01578.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
New direct and indirect acting factor Xa (FXa) and thrombin inhibitors are being developed to overcome the downsides of the conventional anticoagulants - unfractionated and low molecular weight heparins and vitamin K antagonists. Ximelagatran and idraparinux failed to demonstrate an acceptable safety profile. Rivaroxaban and dabigatran are approved for the post-operative prevention of thromboembolic complications after elective hip or knee replacement surgery; dabigatran is approved for the prevention of embolism in patients with atrial fibrillation in an increasing number of countries. Several novel indirect antithrombin-dependent anticoagulants as well as antithrombin-independent oral direct FXa and thrombin inhibitors are investigated in multiple indications for the prophylaxis and treatment of venous thromboembolism and the prophylaxis of arterial thrombotic disorders. Quality-adjusted life years costs and incremental cost-effectiveness ratios are relatively high at present, but may decrease after approval of more new anticoagulants for additional indications.
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Affiliation(s)
- Job Harenberg
- Clinical Pharmacology, Mannheim, Ruprecht-Karls-University Heidelberg, Mannheim, Germany.
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7
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Abstract
Apixaban (BMS-562247; 1-(4-methoxyphenyl)-7-oxo-6-(4-(2-oxopiperidin-1-yl)phenyl)-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxamide), a direct inhibitor of activated factor X (FXa), is in development for the prevention and treatment of various thromboembolic diseases. With an inhibitory constant of 0.08 nM for human FXa, apixaban has greater than 30,000-fold selectivity for FXa over other human coagulation proteases. It produces a rapid onset of inhibition of FXa with association rate constant of 20 μM⁻¹/s approximately and inhibits free as well as prothrombinase- and clot-bound FXa activity in vitro. Apixaban also inhibits FXa from rabbits, rats and dogs, an activity which parallels its antithrombotic potency in these species. Although apixaban has no direct effects on platelet aggregation, it indirectly inhibits this process by reducing thrombin generation. Pre-clinical studies of apixaban in animal models have demonstrated dose-dependent antithrombotic efficacy at doses that preserved hemostasis. Apixaban improves pre-clinical antithrombotic activity, without excessive increases in bleeding times, when added on top of aspirin or aspirin plus clopidogrel at their clinically relevant doses. Apixaban has good bioavailability, low clearance and a small volume of distribution in animals and humans, and a low potential for drug-drug interactions. Elimination pathways for apixaban include renal excretion, metabolism and biliary/intestinal excretion. Although a sulfate conjugate of Ο-demethyl apixaban (O-demethyl apixaban sulfate) has been identified as the major circulating metabolite of apixaban in humans, it is inactive against human FXa. Together, these non-clinical findings have established the favorable pharmacological profile of apixaban, and support the potential use of apixaban in the clinic for the prevention and treatment of various thromboembolic diseases.
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Affiliation(s)
- Pancras C Wong
- Department of Cardiovascular Biology, Bristol-Myers Squibb Company, 311 Pennington-Rocky Hill Road, Pennington, NJ 08534, USA.
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8
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He K, Luettgen JM, Zhang D, He B, Grace JE, Xin B, Pinto DJP, Wong PC, Knabb RM, Lam PYS, Wexler RR, Grossman SJ. Preclinical pharmacokinetics and pharmacodynamics of apixaban, a potent and selective factor Xa inhibitor. Eur J Drug Metab Pharmacokinet 2011; 36:129-39. [PMID: 21461793 DOI: 10.1007/s13318-011-0037-x] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Accepted: 03/15/2011] [Indexed: 11/26/2022]
Abstract
Apixaban is a potent, highly selective, reversible, oral, direct factor Xa (fXa) inhibitor in development for thrombosis prevention and treatment. The preclinical pharmacokinetic (PK) attributes of apixaban feature small volume of distribution (Vd), low systemic clearance (CL), and good oral bioavailability. Apixaban is well absorbed in rat, dog, and chimpanzee, with absolute oral bioavailability of approximately 50% or greater. The steady-state Vd of apixaban is approximately 0.5, 0.2, and 0.17 l/kg in rats, dogs, and chimpanzees, while CL is approximately 0.9, 0.04, and 0.018 l/h/kg, respectively. In vitro metabolic clearance of apixaban is also low. Renal clearance comprises approximately 10-30% of systemic clearance in rat, dog, and chimpanzee. Anti-fXa activity, prothrombin time (PT), and HEPTEST(®) clotting time (HCT) prolongation correlated well with plasma apixaban concentration in rat, dog and chimpanzee. There was no lag time between apixaban plasma concentration and the pharmacodynamic (PD) markers, suggesting a rapid onset of action of apixaban. The PK/PD analyses were performed using an inhibitory E (max) model for anti-fXa assay and a linear model for PT and HCT assays. The IC(50) values for anti-fXa activity were 0.73 ± 0.03 and 1.5 ± 0.15 μM for rat and dog, respectively. The apparent K ( i ) values for PT were approximately 1.7, 6.6, and 4.8 μM for rat, dog and chimpanzee, respectively. The apparent K ( i ) for HCT was approximately 1.3 μM for dog. Apixaban exhibits desirable PK and PD properties for clinical development with good oral bioavailability, small Vd, low CL, and direct, predictable, concentration-dependent PD responses.
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Affiliation(s)
- Kan He
- Pharmaceutical Candidate Optimization, Bristol-Myers Squibb Company, Princeton, NJ, USA
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9
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Ogawa S, Koretsune Y, Yasaka M, Aizawa Y, Atarashi H, Inoue H, Kamakura S, Kumagai K, Mitamura H, Okumura K, Sugi K, Yamashita T. Antithrombotic Therapy in Atrial Fibrillation - Evaluation and Positioning of New Oral Anticoagulant Agents -. Circ J 2011; 75:1539-47. [DOI: 10.1253/circj.cj-11-0304] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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10
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Maitz MF, Sperling C, Werner C. Immobilization of the irreversible thrombin inhibitor D-Phe-Pro-Arg-chloromethylketone: a concept for hemocompatible surfaces? J Biomed Mater Res A 2010; 94:905-12. [PMID: 20730927 DOI: 10.1002/jbm.a.32780] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The irreversible thrombin inhibitor D-Phe-Pro-Arg-chloromethylketone (PPACK) was covalently immobilized to PEGylated polymer thin films at its primary alpha-amino group. Activity assays and capture of radioconjugated thrombin reveal that the PPACK-decorated surfaces could bind thrombin forming up to 30% of a monolayer density. Back-calculation of this high thrombin-inhibiting capacity indicated that the surface immobilization of the inhibitor was still associated with more than two orders of magnitude of loss of activity; increasing activity was observed at higher surface densities. PPACK-containing polymer films almost duplicated the plasma coagulation time when compared with the reference substrate without inhibitor. In whole blood, however, the anticoagulant properties were below those previously found for benzamidine-type reversible thrombin inhibitors; in addition, the surface exhibited inflammatory properties. It is concluded that immobilized reversible thrombin inhibitors are more effective by passivating higher amounts of thrombin in a cooperative action with antithrombin III.
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Affiliation(s)
- Manfred F Maitz
- Max Bergmann Center of Biomaterials Dresden, Leibniz Institute of Polymer Research Dresden, Dresden, Germany.
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11
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Schaden E, Kozek-Langenecker SA. Direct thrombin inhibitors: pharmacology and application in intensive care medicine. Intensive Care Med 2010; 36:1127-37. [PMID: 20425104 DOI: 10.1007/s00134-010-1888-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2009] [Accepted: 03/24/2010] [Indexed: 01/31/2023]
Abstract
PURPOSE Anticoagulation is part of the daily routine of intensive care physicians. As the possibilities of pharmacological anticoagulation are becoming more numerous and diverse, intensive care physicians have to be familiar with indications, contraindications, dosing, and reversal of many different substances. This paper presents an overview of the substance group of direct thrombin inhibitors (DTI) indicated for alternative anticoagulation in intensive care medicine. METHODS The review is a synopsis of scientific evidence, expert opinion, open forum commentary, and clinical feasibility data. RESULTS AND CONCLUSIONS Due to their antithrombotic potential without direct activation of platelets, DTI could offer potential advantages over heparins and vitamin K antagonists in critically ill patients, especially regarding heparin-induced thrombocytopenia. Because of multiple organ dysfunction, organ failure, and comedications, simple extrapolation of results of medical to critically ill patients is not permissible. The fine line between thrombosis and bleeding in intensive care patients requires cautious dosing and close drug monitoring. Studies dealing with DTI in the intensive care setting are of utmost clinical interest.
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Affiliation(s)
- Eva Schaden
- Department of Anesthesiology, General Intensive Care and Pain Management, Medical University of Vienna, Währinger Guertel 18-20, 1090, Vienna, Austria.
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12
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Phenyltriazolinones as potent factor Xa inhibitors. Bioorg Med Chem Lett 2010; 20:1373-7. [PMID: 20100660 DOI: 10.1016/j.bmcl.2010.01.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2009] [Revised: 12/27/2009] [Accepted: 01/04/2010] [Indexed: 11/22/2022]
Abstract
We have discovered that phenyltriazolinone is a novel and potent P1 moiety for coagulation factor Xa. X-ray structures of the inhibitors with a phenyltriazolinone in the P1 position revealed that the side chain of Asp189 has reoriented resulting in a novel S1 binding pocket which is larger in size to accommodate the phenyltriazolinone P1 substrate.
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13
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Stangier J, Clemens A. Pharmacology, pharmacokinetics, and pharmacodynamics of dabigatran etexilate, an oral direct thrombin inhibitor. Clin Appl Thromb Hemost 2009; 15 Suppl 1:9S-16S. [PMID: 19696042 DOI: 10.1177/1076029609343004] [Citation(s) in RCA: 236] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Dabigatran etexilate is a novel, oral reversible direct thrombin inhibitor that is rapidly absorbed and converted to its active form, dabigatran. Dabigatran has been shown to be a potent, competitive, and reversible inhibitor of thrombin, inhibiting both thrombin activity and generation. Studies in healthy volunteers and in patients undergoing orthopedic surgery indicate that dabigatran has a predictable pharmacokinetic profile, allowing for a fixed-dose regimen without the need for coagulation monitoring. In healthy volunteers, peak plasma concentrations of dabigatran are reached approximately 2 hours after oral administration. The elimination half-life is 12 to 14 hours, with clearance predominantly occurring via renal excretion of unchanged drug. Dabigatran is not metabolized by cytochrome P450 isoenzymes, has no interactions with food, and also has a low potential for drug-drug interactions. The pharmacokinetic profile of dabigatran is consistent across a broad range of different patient populations and is unaffected by gender, body weight, ethnic origin, obesity, and mild-to-moderate hepatic impairment. Small differences in dabigatran pharmacokinetics associated with age are attributable to variation in renal function. Dabigatran etexilate produces a predictable pharmacodynamic effect and requires no coagulation monitoring. It has been approved in the European Union (EU) and Canada for prophylaxis of thromboembolism in patients undergoing total knee or hip arthroplasty. Ongoing clinical trials are investigating its use in the treatment of venous thromboembolism, prevention of stroke in patients with nonvalvular atrial fibrillation, and treatment of thromboembolic complications, following acute coronary syndromes.
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Affiliation(s)
- Joachim Stangier
- Department of Drug Metabolism and Pharmacokinetics, Boehringer Ingelheim Pharma GmbH & Co. KG, Birkendorfer Strasse, Biberach an der Riss, Germany.
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14
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Li X, He X, Wang B, Merz K. Conformational variability of benzamidinium-based inhibitors. J Am Chem Soc 2009; 131:7742-54. [PMID: 19435349 DOI: 10.1021/ja9010833] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Determining the structure of a small molecule bound to a biological receptor (e.g., a protein implicated in a disease state) is a necessary step in structure-based drug design. The preferred conformation of a small molecule can change when bound to a protein, and a detailed knowledge of the preferred conformation(s) of a bound ligand can help in optimizing the affinity of a molecule for its receptor. However, the quality of a protein/ligand complex determined using X-ray crystallography is dependent on the size of the protein, the crystal quality, and the realized resolution. The energy restraints used in traditional X-ray refinement procedures typically use "reduced" (i.e., neglect of electrostatics and dispersion interactions) Engh and Huber force field models that, while quite suitable for modeling proteins, often are less suitable for small molecule structures due to a lack of validated parameters. Through the use of ab initio QM/MM-based X-ray refinement procedures, this shortcoming can be overcome especially in the active site or binding site of a small-molecule inhibitor. Herein, we demonstrate that ab initio QM/MM refinement of an inhibitor/protein complex provides insights into the binding of small molecules beyond what is available using more traditional refinement protocols. In particular, QM/MM refinement studies of benzamidinium derivatives show variable conformational preferences depending on the refinement protocol used and the nature of the active-site region.
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Affiliation(s)
- Xue Li
- Department of Chemistry, Quantum Theory Project, 2328 New Physics Building, P.O. Box 118435, University of Florida, Gainesville, Florida 32611-8435, USA
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15
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A new non-natural arginine-like amino acid derivative with a sulfamoyl group in the side-chain. Amino Acids 2009; 38:691-700. [DOI: 10.1007/s00726-009-0267-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2008] [Accepted: 02/19/2009] [Indexed: 10/21/2022]
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16
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[Direct thrombin inhibitors: pharmacology and application in cardiovascular anesthesia]. Anaesthesist 2009; 57:597-606. [PMID: 18311550 DOI: 10.1007/s00101-008-1347-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The options for drug-controlled anticoagulation are becoming noticeably more manifold. In the area of anaesthesiology and intensive care, there are furthermore special disease patterns, such as heparin-induced thrombocytopenia (HIT) to be known, diagnosed and treated. This article gives a review of the substance groups of the direct thrombin inhibitors (DTI) as alternative anticoagulants for HIT in combination with cardiovascular diseases. For the administration of DTIs, experience and the correct dose are the keys to success and are the deciding factors for the two sides of haemostasis: thrombosis and haemorrhage.
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17
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Joo SS, Won TJ, Kim JS, Yoo YM, Tak ES, Park SY, Park HY, Hwang KW, Park SC, Lee DI. Inhibition of Coagulation Activation and Inflammation by a Novel Factor Xa Inhibitor Synthesized from the Earthworm Eisenia andrei. Biol Pharm Bull 2009; 32:253-8. [DOI: 10.1248/bpb.32.253] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Seong Soo Joo
- Research Institute of Veterinary Medicine, Chungbuk National University
| | - Tae Joon Won
- Department of Immunology, College of Pharmacy, Chung-Ang University
| | - Jong Sung Kim
- Department of Immunology, College of Pharmacy, Chung-Ang University
| | - Yeong Min Yoo
- Research Institute of Veterinary Medicine, Chungbuk National University
| | - Eun Sik Tak
- Department of Life Science, Chung-Ang University
| | - So-Young Park
- Environmental Toxico-Genomic & Proteomic Center, College of Medicine, Korea University
| | - Hee Yong Park
- Department of Immunology, College of Pharmacy, Chung-Ang University
| | - Kwang Woo Hwang
- Department of Immunology, College of Pharmacy, Chung-Ang University
| | | | - Do Ik Lee
- Department of Immunology, College of Pharmacy, Chung-Ang University
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Eriksson BI, Quinlan DJ, Weitz JI. Comparative Pharmacodynamics and Pharmacokinetics of Oral Direct Thrombin and Factor Xa Inhibitors in Development. Clin Pharmacokinet 2009; 48:1-22. [PMID: 19071881 DOI: 10.2165/0003088-200948010-00001] [Citation(s) in RCA: 363] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Bengt I Eriksson
- Orthopaedics Department, University Hospital Sahlgrenska/Ostra, Gothenburg, Sweden.
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19
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Wu E, Han K, Zhang J. Selectivity of Neutral/Weakly Basic P1 Group Inhibitors of Thrombin and Trypsin by a Molecular Dynamics Study. Chemistry 2008; 14:8704-14. [DOI: 10.1002/chem.200800277] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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20
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Stangier J. Clinical pharmacokinetics and pharmacodynamics of the oral direct thrombin inhibitor dabigatran etexilate. Clin Pharmacokinet 2008; 47:285-95. [PMID: 18399711 DOI: 10.2165/00003088-200847050-00001] [Citation(s) in RCA: 455] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The direct thrombin inhibitor dabigatran etexilate is currently in phase III of development for the prophylaxis and treatment of thromboembolic disorders, with three trials completed in primary venous thromboembolism (VTE) prevention. Dabigatran etexilate is an orally administered prodrug, which is rapidly absorbed and converted to the active form, dabigatran. Dabigatran has been shown to specifically and reversibly inhibit thrombin, the key enzyme in the coagulation cascade. Studies in healthy volunteers and in patients undergoing orthopaedic surgery have indicated that dabigatran has a predictable pharmacokinetic/pharmacodynamic profile, allowing for a fixed-dose regimen. Peak plasma concentrations of dabigatran are reached approximately 2 hours after oral administration in healthy volunteers, with no unexpected accumulation of drug concentrations upon multiple dosing. Excretion is predominantly via the renal route as unchanged drug. Dabigatran is not metabolized by cytochrome P450 isoenzymes. The small differences in dabigatran pharmacokinetics associated with age and gender are attributed to variations in renal function. Additional studies have shown that the pharmacokinetic/pharmacodynamic profile of dabigatran is consistent across a range of patient populations, with no effect of moderate hepatic impairment being observed. Drug-drug interactions are not observed with concomitant administration of atorvastatin, diclofenac or digoxin. The pharmacodynamic profile of dabigatran demonstrates effective anticoagulation combined with a low risk of bleeding. Further phase III studies are ongoing, including acute VTE treatment and stroke prevention in atrial fibrillation; the results obtained so far show that dabigatran etexilate is well tolerated and effective in the treatment and prevention of thromboembolic events.
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Imaeda Y, Kuroita T, Sakamoto H, Kawamoto T, Tobisu M, Konishi N, Hiroe K, Kawamura M, Tanaka T, Kubo K. Discovery of imidazo[1,5-c]imidazol-3-ones: weakly basic, orally active factor Xa inhibitors. J Med Chem 2008; 51:3422-36. [PMID: 18507371 DOI: 10.1021/jm701548u] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The coagulation enzyme factor Xa (FXa) has been recognized as a promising target for the development of new antithrombotic agents. We previously found compound 1 to be an orally bioavailable FXa inhibitor in fasted monkeys; however, 1 showed poor bioavailability in rats and fed monkeys. To work out the pharmacokinetic problems, we focused our synthetic efforts on the chemical conversion of the 4-(imidazo[1,2- a]pyridin-5-yl)piperazine moiety of 1 to imidazolylpiperidine derivatives (fused and nonfused), which resulted in the discovery of the weakly basic imidazo[1,5- c]imidazol-3-one 3q as a potent and selective FXa inhibitor. Compound 3q showed favorable oral bioavailability in rats and monkeys under both fasted and fed conditions and antithrombotic efficacy in a rat model of venous thrombosis after oral administration, without a significant increase in bleeding time (unlike warfarin). On the basis of these promising properties, compound 3q was selected for further evaluation.
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Affiliation(s)
- Yasuhiro Imaeda
- Pharmaceutical Research Division, Takeda Pharmaceutical Co., Ltd., 2-17-85, Jusohonmachi, Yodogawa-ku, Osaka 532-8686, Japan.
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22
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Smallheer JM, Wang S, Laws ML, Nakajima S, Hu Z, Han W, Jacobson I, Luettgen JM, Rossi KA, Rendina AR, Knabb RM, Wexler RR, Lam PY, Quan ML. Sulfonamidolactam inhibitors of coagulation factor Xa. Bioorg Med Chem Lett 2008; 18:2428-33. [DOI: 10.1016/j.bmcl.2008.02.054] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2008] [Revised: 02/14/2008] [Accepted: 02/21/2008] [Indexed: 11/25/2022]
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23
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Imaeda Y, Miyawaki T, Sakamoto H, Itoh F, Konishi N, Hiroe K, Kawamura M, Tanaka T, Kubo K. Discovery of sulfonylalkylamides: A new class of orally active factor Xa inhibitors. Bioorg Med Chem 2008; 16:2243-60. [DOI: 10.1016/j.bmc.2007.11.073] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2007] [Revised: 11/22/2007] [Accepted: 11/27/2007] [Indexed: 10/22/2022]
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24
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Pinto DJP, Orwat MJ, Koch S, Rossi KA, Alexander RS, Smallwood A, Wong PC, Rendina AR, Luettgen JM, Knabb RM, He K, Xin B, Wexler RR, Lam PYS. Discovery of 1-(4-methoxyphenyl)-7-oxo-6-(4-(2-oxopiperidin-1-yl)phenyl)-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxamide (apixaban, BMS-562247), a highly potent, selective, efficacious, and orally bioavailable inhibitor of blood coagulation factor Xa. J Med Chem 2007; 50:5339-56. [PMID: 17914785 DOI: 10.1021/jm070245n] [Citation(s) in RCA: 310] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Efforts to identify a suitable follow-on compound to razaxaban (compound 4) focused on modification of the carboxamido linker to eliminate potential in vivo hydrolysis to a primary aniline. Cyclization of the carboxamido linker to the novel bicyclic tetrahydropyrazolopyridinone scaffold retained the potent fXa binding activity. Exceptional potency of the series prompted an investigation of the neutral P1 moieties that resulted in the identification of the p-methoxyphenyl P1, which retained factor Xa binding affinity and good oral bioavailability. Further optimization of the C-3 pyrazole position and replacement of the terminal P4 ring with a neutral heterocycle culminated in the discovery of 1-(4-methoxyphenyl)-7-oxo-6-(4-(2-oxopiperidin-1-yl)phenyl)-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxamide (apixaban, compound 40). Compound 40 exhibits a high degree of fXa potency, selectivity, and efficacy and has an improved pharmacokinetic profile relative to 4.
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Affiliation(s)
- Donald J P Pinto
- Discovery Chemistry, Research and Development, Bristol-Myers Squibb Company, 31 Pennington-Rocky Hill Road, Pennington, New Jersey 08534, USA.
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25
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Friedrich R, Riester D, Göttig P, Thürk M, Schwienhorst A, Bode W. Structure of a novel thrombin inhibitor with an uncharged D-amino acid as P1 residue. Eur J Med Chem 2007; 43:1330-5. [PMID: 17950494 DOI: 10.1016/j.ejmech.2007.07.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2005] [Revised: 07/22/2007] [Accepted: 07/26/2007] [Indexed: 11/17/2022]
Abstract
Thrombin, the ultimate proteinase of the coagulation cascade, is an attractive target for the treatment of a variety of cardiovascular diseases. Previously, a series of novel thrombin inhibitors, discovered by employing a powerful and new computer-assisted multiparameter optimization process (CADDIS), have been synthesized. We have now crystallized the complex of human alpha-thrombin with the most potent of these inhibitors, 8-5 (K(i)=3 nM), and have determined its 2.3A X-ray crystal structure. The Fourier map displayed clear electron density for the inhibitor. The central part of the inhibitor binds in an improved melagatran-like mode, while the structure identifies a d-tyrosine as P1 residue which forms a charged hydrogen bond with Asp 189 of thrombin. This is the first crystal structure of a thrombin-inhibitor complex, where an uncharged inhibitor residue makes hydrogen bonds within the thrombin S1 pocket. Additionally, novel favourable intermolecular hydrogen bonds of the inhibitor with the thrombin backbone become possible due to the d-configuration of the P1 residue. Two flanking voluminous side chains increase the strength of the subjacent hydrogen bonding system by shielding it from the bulk solvent.
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Affiliation(s)
- Rainer Friedrich
- Arbeitsgruppe Proteinaseforschung, Max-Planck-Institut für Biochemie, Am Klopferspitz 18, 82152 Martinsried, Germany
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26
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Ishihara T, Seki N, Hirayama F, Orita M, Koshio H, Taniuchi Y, Sakai-Moritani Y, Iwatsuki Y, Kaku S, Kawasaki T, Matsumoto Y, Tsukamoto SI. Prodrug-based design, synthesis, and biological evaluation of N-benzenesulfonylpiperidine derivatives as novel, orally active factor Xa inhibitors. Bioorg Med Chem 2007; 15:4175-92. [PMID: 17416533 DOI: 10.1016/j.bmc.2007.03.066] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2007] [Revised: 03/20/2007] [Accepted: 03/21/2007] [Indexed: 10/23/2022]
Abstract
We describe here our investigation of a new series of orally active fXa inhibitors based on a prodrug strategy. Solid-phase parallel synthesis identified a unique series of fXa inhibitors with a substituted benzenesulfonyl group as a novel S4 binding element. This series resulted in compound 39, which exhibited potent inhibitory activity against fXa (IC50 = 13 nM) and excellent selectivity over thrombin (>7000-fold). The masking of its highly hydrophilic groups led to the creation of related prodrug 28, which demonstrated an anticoagulant effect after oral dosing.
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Affiliation(s)
- Tsukasa Ishihara
- Drug Discovery Research, Astellas Pharma Inc., 21 Miyukigaoka, Tsukuba, Ibaraki 305-8585, Japan.
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27
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Wienen W, Stassen JM, Priepke H, Ries UJ, Hauel N. Antithrombotic and anticoagulant effects of the direct thrombin inhibitor dabigatran, and its oral prodrug, dabigatran etexilate, in a rabbit model of venous thrombosis. J Thromb Haemost 2007; 5:1237-42. [PMID: 17362226 DOI: 10.1111/j.1538-7836.2007.02526.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Oral anticoagulant therapies targeted at thrombin are being developed to overcome limitations associated with current standard therapies. OBJECTIVES This study was undertaken to assess and compare the antithrombotic and anticoagulant effects of the novel, selective and reversible, direct thrombin inhibitor (DTI), dabigatran, and its oral prodrug dabigatran etexilate, to that of unfractionated heparin (UFH), hirudin and melagatran using a rabbit model of venous thrombosis. METHODS A rabbit model of venous thrombosis consisting of endothelial damage with blood flow reduction was used with minor modifications. RESULTS All compounds demonstrated a dose-dependent reduction in thrombus formation following i.v. administration with complete or almost complete inhibition at the highest doses. Dabigatran (in the dose range 0.03-0.5 mg kg(-1)) had a 50% effective dose of 0.066 mg kg(-1). By comparison, UFH (5-50 U kg(-1)), hirudin (0.01-0.05 mg kg(-1)) and melagatran (0.01-0.3 mg kg(-1)) had a 50% effective dose of 9.8 U kg(-1), 0.016 mg kg(-1) and 0.058 mg kg(-1), respectively. Similarly, oral dabigatran etexilate (1-20 mg kg(-1)) inhibited thrombus formation in a dose-dependent manner. Maximum inhibition was achieved within 1 h of administration, suggesting a rapid onset of action. For both routes of administration, inhibition of thrombus formation directly correlated with prolongation of the activated partial thromboplastin time. CONCLUSIONS These findings demonstrate the potent anticoagulant and antithrombotic activity of dabigatran as a selective thrombin inhibitor in a rabbit model of venous thrombosis. Notably, dose-dependent and long-lasting antithrombotic efficacy was observed after application of its oral form dabigatran etexilate, which is currently undergoing phase III clinical development.
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Affiliation(s)
- W Wienen
- Department of Pulmonary Research, Boehringer Ingelheim Pharma GmbH and Co KG, Biberach, Germany.
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28
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Ye B, Arnaiz DO, Chou YL, Griedel BD, Karanjawala R, Lee W, Morrissey MM, Sacchi KL, Sakata ST, Shaw KJ, Wu SC, Zhao Z, Adler M, Cheeseman S, Dole WP, Ewing J, Fitch R, Lentz D, Liang A, Light D, Morser J, Post J, Rumennik G, Subramanyam B, Sullivan ME, Vergona R, Walters J, Wang YX, White KA, Whitlow M, Kochanny MJ. Thiophene-anthranilamides as highly potent and orally available factor Xa inhibitors. J Med Chem 2007; 50:2967-80. [PMID: 17536795 DOI: 10.1021/jm070125f] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
There remains a high unmet medical need for a safe oral therapy for thrombotic disorders. The serine protease factor Xa (fXa), with its central role in the coagulation cascade, is among the more promising targets for anticoagulant therapy and has been the subject of intensive drug discovery efforts. Investigation of a hit from high-throughput screening identified a series of thiophene-substituted anthranilamides as potent nonamidine fXa inhibitors. Lead optimization by incorporation of hydrophilic groups led to the discovery of compounds with picomolar inhibitory potency and micromolar in vitro anticoagulant activity. Based on their high potency, selectivity, oral pharmacokinetics, and efficacy in a rat venous stasis model of thrombosis, compounds ZK 814048 (10b), ZK 810388 (13a), and ZK 813039 (17m) were advanced into development.
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Affiliation(s)
- Bin Ye
- Berlex Biosciences, Post Office Box 4099, Richmond, California 94804-0099, USA.
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29
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Saitoh F, Nishida H, Mukaihira T, Aikawa K, Mikami K. Dynamic Kinetic Resolution for the Catalytic Asymmetric Total Synthesis of Antithrombotic Agents M58163 and M58169. Adv Synth Catal 2007. [DOI: 10.1002/adsc.200600611] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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30
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Saitoh F, Nishida H, Mukaihira T, Kosuga N, Ohkouchi M, Matsusue T, Shiromizu I, Hosaka Y, Matsumoto M, Yamamoto I. Synthesis and Evaluation of 1-Arylsulfonyl-3-piperazinone Derivatives as Factor Xa Inhibitors VI. A Series of New Derivatives Containing N,S- and N,SO2-Spiro Acetal Scaffolds. Chem Pharm Bull (Tokyo) 2007; 55:317-23. [PMID: 17268108 DOI: 10.1248/cpb.55.317] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In the course of development of factor Xa (FXa) inhibitors, we have found unique compounds containing an N,O- and an N,N-spiro acetal structure. It appeared that the difference in overall conformation due to the N,X-spiro acetal structure might be important for FXa inhibitory activity. Therefore, other N,X-spiro acetal structures, an N,S- and an N,SO2-spiro acetal, were developed as analogues of the N,X-spiro acetal structure. Compound 7b (N,S-spiro acetal structure) was found to have the strongest activity in these series of N,X-spiro acetal compounds, which had ever been synthesized.(4,5)).
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Affiliation(s)
- Fumihiko Saitoh
- Pharmaceutical Research Center, Mochida Pharmaceutical Co., Ltd., Gotemba, Shizuoka, Japan.
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31
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Qiao JX, Cheng X, Smallheer JM, Galemmo RA, Drummond S, Pinto DJP, Cheney DL, He K, Wong PC, Luettgen JM, Knabb RM, Wexler RR, Lam PYS. Pyrazole-based factor Xa inhibitors containing N-arylpiperidinyl P4 residues. Bioorg Med Chem Lett 2006; 17:1432-7. [PMID: 17174550 DOI: 10.1016/j.bmcl.2006.11.071] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2006] [Accepted: 11/29/2006] [Indexed: 11/19/2022]
Abstract
The synthesis, SAR, pharmacokinetic profile, and modeling studies of both monocyclic and fused pyrazoles containing substituted N-arylpiperidinyl P4 moieties that are potent and selective factor Xa inhibitors will be discussed. Fused pyrazole analog 16a, with a 2'-methylsulfonylphenyl piperidine P4 group, was shown to be the best compound in this series (FXa Ki = 0.35 nM) based on potency, selectivity, and pharmacokinetic profile.
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Affiliation(s)
- Jennifer X Qiao
- Bristol-Myers Squibb Pharmaceutical Research Institute, PO Box 5400, Princeton, NJ 08543-5400, USA.
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32
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Pinto DJP, Galemmo RA, Quan ML, Orwat MJ, Clark C, Li R, Wells B, Woerner F, Alexander RS, Rossi KA, Smallwood A, Wong PC, Luettgen JM, Rendina AR, Knabb RM, He K, Wexler RR, Lam PYS. Discovery of potent, efficacious, and orally bioavailable inhibitors of blood coagulation factor Xa with neutral P1 moieties. Bioorg Med Chem Lett 2006; 16:5584-9. [PMID: 16963264 DOI: 10.1016/j.bmcl.2006.08.027] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2006] [Revised: 08/02/2006] [Accepted: 08/03/2006] [Indexed: 10/24/2022]
Abstract
The bicyclic dihydropyrazolopyridinone scaffold allowed for incorporation of multiple P1 moieties with subnanomolar binding affinities for blood coagulation factor Xa. The compound 3-[6-(2'-dimethylaminomethyl-biphenyl-4-yl)-7-oxo-3-trifluoro-methyl-4,5,6,7-tetrahydro-pyrazolo[3,4-c]pyridine-l-yl]-benzamide 6d shows good fXa potency, selectivity, in vivo efficacy and oral bioavailability. Compound 6d was selected for further pre-clinical evaluations.
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Affiliation(s)
- Donald J P Pinto
- Discovery Chemistry Bristol-Myers Squibb Pharmaceutical Research Institute, Princeton, NJ 08543, USA.
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33
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Pinto DJP, Orwat MJ, Quan ML, Han Q, Galemmo RA, Amparo E, Wells B, Ellis C, He MY, Alexander RS, Rossi KA, Smallwood A, Wong PC, Luettgen JM, Rendina AR, Knabb RM, Mersinger L, Kettner C, Bai S, He K, Wexler RR, Lam PYS. 1-[3-Aminobenzisoxazol-5′-yl]-3-trifluoromethyl-6-[2′-(3-(R)-hydroxy-N-pyrrolidinyl)methyl-[1,1′]-biphen-4-yl]-1,4,5,6-tetrahydropyrazolo-[3,4-c]-pyridin-7-one (BMS-740808) a highly potent, selective, efficacious, and orally bioavailable inhibitor of blood coagulation factor Xa. Bioorg Med Chem Lett 2006; 16:4141-7. [PMID: 16730984 DOI: 10.1016/j.bmcl.2006.02.069] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2006] [Revised: 02/15/2006] [Accepted: 02/17/2006] [Indexed: 11/26/2022]
Abstract
Attempts to further optimize the pyrazole factor Xa inhibitors centered on masking the aryl aniline P4 moiety. Scaffold optimization resulted in the identification of a novel bicyclic pyrazolo-pyridinone scaffold which retained fXa potency. The novel bicyclic scaffold preserved all binding interactions observed with the monocyclic counterpart and importantly the carboxamido moiety was integrated within the scaffold making it less susceptible to hydrolysis. These efforts led to the identification of 1-[3-aminobenzisoxazol-5'-yl]-3-trifluoromethyl-6-[2'-(3-(R)-hydroxy-N-pyrrolidinyl)methyl-[1,1']-biphen-4-yl]-1,4,5,6-tetrahydropyrazolo-[3,4-c]-pyridin-7-one 6f (BMS-740808), a highly potent (fXa Ki=30 pM) with a rapid onset of inhibition (2.7x10(7) M-1 s-1) in vitro, selective (>1000-fold over other proteases), efficacious in the AVShunt thrombosis model, and orally bioavailable inhibitor of blood coagulation factor Xa.
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Affiliation(s)
- Donald J P Pinto
- Discovery Chemistry Bristol-Myers Squibb Pharmaceutical Research Institute, Princeton, NJ 08543, USA.
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34
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Quan ML, Han Q, Fevig JM, Lam PYS, Bai S, Knabb RM, Luettgen JM, Wong PC, Wexler RR. Aminobenzisoxazoles with biaryl P4 moieties as potent, selective, and orally bioavailable factor Xa inhibitors. Bioorg Med Chem Lett 2006; 16:1795-8. [PMID: 16434195 DOI: 10.1016/j.bmcl.2006.01.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2005] [Revised: 01/04/2006] [Accepted: 01/05/2006] [Indexed: 10/25/2022]
Abstract
We have previously reported on a series of aminobenzisoxazoles as potent, selective, and orally bioavailable factor Xa inhibitors, which culminated in the discovery of razaxaban. Herein, we describe another approach to improve factor Xa inhibitory potency and pharmacokinetic profile by incorporating basic and water soluble functionalities on the terminal ring of the P4 biaryl group found in our earlier Xa inhibitors. This approach resulted in a series of potent, selective, and orally bioavailable factor Xa inhibitors.
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Affiliation(s)
- Mimi L Quan
- Discovery Chemistry, Bristol-Myers Squibb Pharmaceutical Research Institute, Princeton, NJ 08543, USA.
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35
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Saitoh F, Mukaihira T, Nishida H, Satoh T, Okano A, Yumiya Y, Ohkouchi M, Johka R, Matsusue T, Shiromizu I, Hosaka Y, Matsumoto M, Ohnishi S. Synthesis and Evaluation of 1-Arylsulfonyl-3-piperazinone Derivatives as Factor Xa Inhibitors V. A Series of New Derivatives Containing a Spiro[imidazo[1,2-a]pyrazine-2(3H),4'-piperidin]-5(1H)-one Scaffold. Chem Pharm Bull (Tokyo) 2006; 54:1535-44. [PMID: 17077550 DOI: 10.1248/cpb.54.1535] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have already reported unique compounds containing a N,O-spiro acetal structure as an orally active factor Xa (FXa) inhibitor. This time, we described a N,N-spiro acetal structure as an analogue of the N,O-spiro acetal structure for an orally active FXa inhibitor. The synthesis of these analogues could be achieved in a similar fashion to the N,O-spiro acetal synthesis. Consequently, FXa inhibitory activity was increased and more active compounds could be found (M58163: IC50 = 0.61 nM, M58169: IC50 = 0.58 nM). Additionally, the absolute configuration could be determined by X-ray crystallography analysis (M58169: (R)-config.).
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Affiliation(s)
- Fumihiko Saitoh
- Pharmaceutical Research Center, Mochida Pharmaceutical Co., Ltd, Gotemba, Shizuoka, Japan.
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36
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Affiliation(s)
- Marcello Di Nisio
- Department of Vascular Medicine, Academic Medical Center, Amsterdam, The Netherlands.
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37
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Yavin YY, Wolozinsky M, Cohen AT. New antithrombotics in the prevention of thromboembolic disease. Eur J Intern Med 2005; 16:257-66. [PMID: 16084352 DOI: 10.1016/j.ejim.2005.03.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2005] [Revised: 03/10/2005] [Accepted: 03/21/2005] [Indexed: 11/20/2022]
Abstract
New anticoagulants are under development to improve on current ones that, although effective, have limitations in efficacy, safety and convenience. We have reviewed the use of these agents as thromboprophylactic drugs. These new agents have more specific modes of action and can be divided into three groups. Inhibitors of the initiation of coagulation work via inhibition of the factor VIIa/tissue factor complex. Inhibitors of propagation of coagulation include parenteral and oral factor Xa inhibitors, factor IXa inhibitors, inhibitors of factor Va and VIIIa, activated Protein C, soluble thrombomodulin and SNAC-Heparin. Finally, direct inhibitors of thrombin are under development both for parenteral and oral administration. Several new drugs, such as fondaparinux, hirudin, argatroban, bivalirudin and ximelagatran, have already been licensed for specific indications and are being investigated for more general usage. Other drugs reviewed are in much earlier stages of development.
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Affiliation(s)
- Yshai Y Yavin
- Vascular Medicine, Department of Surgery, Guy's, King's and St Thomas School of Medicine, London SE5 9PJ, UK
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38
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Riester D, Wirsching F, Salinas G, Keller M, Gebinoga M, Kamphausen S, Merkwirth C, Goetz R, Wiesenfeldt M, Stürzebecher J, Bode W, Friedrich R, Thürk M, Schwienhorst A. Thrombin inhibitors identified by computer-assisted multiparameter design. Proc Natl Acad Sci U S A 2005; 102:8597-602. [PMID: 15937115 PMCID: PMC1150832 DOI: 10.1073/pnas.0501983102] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2004] [Indexed: 11/18/2022] Open
Abstract
Here, we present a series of thrombin inhibitors that were generated by using powerful computer-assisted multiparameter optimization process. The process was organized in design cycles, starting with a set of randomly chosen molecules. Each cycle combined combinatorial synthesis, multiparameter characterization of compounds in a variety of bioassays, and algorithmic processing of the data to devise a set of compounds to be synthesized in the next cycle. The identified lead compounds exhibited thrombin inhibitory constants in the lower nanomolar range. They are by far the most selective synthetic thrombin inhibitors, with selectivities of >100,000-fold toward other proteases such as Factor Xa, Factor XIIa, urokinase, plasmin, and Plasma kallikrein. Furthermore, these compounds exhibit a favorable profile, comprising nontoxicity, high metabolic stability, low serum protein binding, good solubility, high anticoagulant activity, and a slow and exclusively renal elimination from the circulation in a rat model. Finally, x-ray crystallographic analysis of a thrombin-inhibitor complex revealed a binding mode with a neutral moiety in the S1 pocket of thrombin.
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Affiliation(s)
- Daniel Riester
- Abteilung für Molekulare Genetik und Präparative Molekularbiologie, Institut für Mikrobiologie und Genetik, Grisebachstrasse 8, 37077 Göttingen, Germany
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39
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Quan ML, Lam PYS, Han Q, Pinto DJP, He MY, Li R, Ellis CD, Clark CG, Teleha CA, Sun JH, Alexander RS, Bai S, Luettgen JM, Knabb RM, Wong PC, Wexler RR. Discovery of 1-(3'-aminobenzisoxazol-5'-yl)-3-trifluoromethyl-N-[2-fluoro-4- [(2'-dimethylaminomethyl)imidazol-1-yl]phenyl]-1H-pyrazole-5-carboxyamide hydrochloride (razaxaban), a highly potent, selective, and orally bioavailable factor Xa inhibitor. J Med Chem 2005; 48:1729-44. [PMID: 15771420 DOI: 10.1021/jm0497949] [Citation(s) in RCA: 161] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Modification of a series of pyrazole factor Xa inhibitors to incorporate an aminobenzisoxazole as the P(1) ligand resulted in compounds with improved selectivity for factor Xa relative to trypsin and plasma kallikrein. Further optimization of the P(4) moiety led to compounds with enhanced permeability and reduced protein binding. The SAR and pharmacokinetic profile of this series of compounds is described herein. These efforts culminated in 1-(3'-aminobenzisoxazol-5'-yl)-3-trifluoromethyl-N-[2-fluoro-4-[(2'-dimethylaminomethyl)imidazol-1-yl]phenyl]-1H-pyrazole-5-carboxyamide (11d), a potent, selective, and orally bioavailable inhibitor of factor Xa. On the basis of its excellent in vitro potency and selectivity profile, high free fraction in human plasma, good oral bioavailability, and in vivo efficacy in antithrombotic models, the HCl salt of this compound was selected for clinical development as razaxaban (DPC 906, BMS-561389).
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Affiliation(s)
- Mimi L Quan
- Discovery Chemistry, Pharmaceutical Research Institute, Bristol-Myers Squibb Co., P.O. Box 5400, Princeton, New Jersey 08543-5400, USA.
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40
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Ilies MA, Supuran CT, Scozzafava A. Therapeutic applications of serine protease inhibitors. Expert Opin Ther Pat 2005. [DOI: 10.1517/13543776.12.8.1181] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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41
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Chi L, Peng YW, Gibson G, Hicks G, Mertz TE, Rapundalo S, Janiczek N, Edmunds JJ, Leadley R. In Vitro and In Vivo Antithrombotic Activity of PD-198961, a Novel Synthetic Factor Xa Inhibitor. J Cardiovasc Pharmacol 2004; 44:493-500. [PMID: 15454859 DOI: 10.1097/01.fjc.0000141475.14007.ab] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PD-198961, 3-(4-5-[(2R,6S)-2,6-dimethyltetrahydro-1(2H)-pyridinyl]pentyl-3-oxo-3,4-dihydro-2-quinoxalinyl)-4-hydroxybenzenecarboximidamide, is a novel, synthetic factor Xa inhibitor with a Ki of 2.7 nM against human factor Xa. The aim of the present study was to evaluate the pharmacokinetic profile and antithrombotic efficacy of PD-198961 in rabbits. When tested in vitro, PD-198961 doubled prothrombin time (PT) and activated partial thromboplastin time (aPTT) at concentrations of 0.13 and 0.32 microM in human plasma, 0.2 and 0.09 microM in rabbit plasma, 0.3 and 0.4 microM in dog plasma, respectively. Intravenous administration of PD-198961 at 1 mg/kg over 30 minutes resulted in a maximal prolongation in PT and aPTT of 4.9 +/- 0.4 and 4.1 +/- 0.9-fold of baseline, respectively. The peak plasma concentration of PD-198961 was 977 +/- 96 ng/ml. The anticoagulant effect of PD-198961 was readily reversible; coagulation parameters and plasma concentration returned to near baseline 15 minutes after cessation of infusion. There was a good correlation between PT prolongation and plasma concentration of PD-198961 (r = 0.93). In an FeCl3-induced model of arterial thrombosis in rabbits, the antithrombotic effects of PD-198961 were compared with that of LB-30057, a direct thrombin inhibitor, and enoxaparin, a low molecular weight heparin (LMWH). PD-198961 dose dependently increased the time to occlusion (TTO), reduced thrombus weight (TW), and decreased the incidence of occlusion. When administered at 3.0 microg/kg/min IV, PD-198961 prolonged TTO from 28 +/- 5 minutes (control) to 120 +/- 0 minutes (P < 0.001) and reduced TW from 9.9 +/- 1.5 mg (control) to 2.8 +/- 0.9 mg (P < 0.01). PD-198961 also dose dependently inhibited ex vivo plasma FXa activity. At the highest dose tested, PD-198961 increased aPTT to 1.4 +/- 0.1-fold of baseline (compared with 1.5 +/- 0.1 and 2.8 +/- 0.3-fold of baseline for LB-30057 [CI-1028] and enoxaparin, respectively), and had modest effects on bleeding time (< or = 2-fold). These results indicate that PD-198961 is a potent FXa inhibitor and an effective antithrombotic agent at doses that produce only modest changes in normal hemostasis.
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Affiliation(s)
- Liguo Chi
- Cardiovascular Pharmacology, Pfizer Global R&D, Ann Arbor Laboratories, Ann Arbor, Michigan 48105, USA.
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Marder VJ, Rosove MH, Minning DM. Foundation and sites of action of antithrombotic agents. Best Pract Res Clin Haematol 2004; 17:3-22. [PMID: 15171955 DOI: 10.1016/j.beha.2004.02.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Thromboembolic disorders are a major cause of morbidity and mortality. As knowledge of the complex interactions between the vessel wall, platelets and coagulation and fibrinolytic enzyme systems increases, new avenues for more effective and safer therapies become evident. In this review, we discuss mechanisms of hemostasis in relation to antithrombotic agents and results of clinical trials using these drugs.
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Affiliation(s)
- Victor J Marder
- Vascular Medicine Program, Los Angeles Orthopedic Hospital, and Division of Hematology-Oncology, Department of Medicine, David Geffen School of Medicine at UCLA, CA, USA.
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Nishida H, Mukaihira T, Saitoh F, Harada K, Fukui M, Matsusue T, Okamoto A, Hosaka Y, Matsumoto M, Shiromizu I, Ohnishi S, Mochizuki H. Synthesis and Evaluation of 1-Arylsulfonyl-3-piperazinone Derivatives as Factor Xa Inhibitors IV. A Series of New Derivatives Containing a Spiro[5H-oxazolo[3,2-a]pyrazine-2(3H),4'-piperidin]-5-one Skeleton. Chem Pharm Bull (Tokyo) 2004; 52:406-12. [PMID: 15056953 DOI: 10.1248/cpb.52.406] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In the course of development of factor Xa (FXa) inhibitor in an investigation involving the synthesis of 1-arylsulfonyl-3-piperazinone derivatives, we found new compounds containing a unique spiro skeleton. Among such compounds, (-)-7-[(6-chloro-2-naphthalenyl)sulfonyl]tetrahydro-8a-(methoxymethyl)-1'-(4-pyridinyl)-spiro[5H-oxazolo[3,2-a]pyrazine-2(3H),4'-piperidin]-5-one (28, M55529) had activity more favorable than those of previously reported compounds. The inhibitory activity of M55529 for FXa is IC(50)=2 nM, with high selectivity for FXa over thrombin and trypsin.
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Affiliation(s)
- Hidemitsu Nishida
- Discovery Research Center, Mochida Pharmaceutical Co., Ltd., Gotemba, Shizuoka, Japan.
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Abstract
The synthetic compound DX-9065a represents a low molecular weight, direct, competitive inhibitor of factor Xa (FXa) with a high affinity and selectivity for the enzyme. Under experimental conditions DX-9065a exerts strong anticoagulant actions in vitro and in vivo and is antithrombotically effective in various thrombosis models. It inhibits proliferation of vascular smooth muscle cells in cell culture systems as well as in in vivo models. As a small molecule inhibitor, DX-9065a inactivates both free and fibrin-bound FXa. By this mechanism it effectively affects the clot-associated procoagulant activity which might be responsible for the propagation of intravascular thrombi as well as for recurrent thrombosis and thrombotic reocclusion after lysis. Although DX-9065a is effective after oral administration, its oral bioavailability is relatively low and seems not to be sufficient for a long-term therapeutic use of the drug. However, first clinical trials in healthy volunteers and in patients with cardiovascular diseases demonstrated a predictable pharmacokinetic and pharmacodynamic behavior of DX-9065a after either intravenous bolus injection or constant infusion, as well as its high safety, especially a lower bleeding risk compared with other commonly used drugs. Further experimental studies and ongoing clinical trials will evaluate the inhibitory profile of the drug, its effectiveness and its possible superiority over other drug regimens in various cardiovascular indications.
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Affiliation(s)
- Brigitte Kaiser
- Friedrich Schiller University Jena, Medical Faculty, Center for Vascular Biology and Medicine, Nordhäuser Strasse 78, D-99089 Erfurt, Germany.
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Johansson S, Wåhlander K, Larson G, Ohlsson L, Larsson M, Eriksson UG. Pharmacokinetics and anticoagulant effect of the direct thrombin inhibitor melagatran following subcutaneous administration to healthy young men. Blood Coagul Fibrinolysis 2003; 14:677-84. [PMID: 14517494 DOI: 10.1097/00001721-200310000-00010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The pharmacokinetic dose linearity and reproducibility, the effects on ex-vivo coagulation time assays and bleeding time, and tolerability of the direct thrombin inhibitor melagatran following subcutaneous (s.c.) dosing were investigated in two open-label studies in healthy males: (i). a dose-escalation study in which subjects received single s.c. doses of melagatran (0.1-5 mg); and (ii). a repeated-dosing study in which 3 mg s.c. melagatran was administered at 12-h intervals for 4 days. In both studies, melagatran was rapidly absorbed with maximum plasma concentrations (C(max)) observed about 0.5 h post dosing. The half-life of melagatran was about 2 h. The area under the melagatran plasma concentration versus time curve increased linearly with dose. No time dependency in the area under the curve or Cmax was observed over 4 days of twice-daily dosing. The variability in pharmacokinetic parameters was low and the bioavailability of melagatran appeared to be complete. There was a steep and linear prolongation of thrombin time, a non-linear prolongation of both activated partial thromboplastin time and activated coagulation time, and a decrease in prothrombin complex activity with increasing melagatran plasma concentration. Only moderate increases in capillary bleeding time were observed with s.c. doses up to 5 mg melagatran. Melagatran was well tolerated after s.c. injection, with good local tolerability at the injection site.
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Abstract
Thrombin has long been a target for development of oral anticoagulants but it has been difficult to find synthetic inhibitors with a desirable combination of pharmacodynamic and pharmacokinetic properties. However, there are now two oral direct thrombin inhibitors (DTIs) in clinical development, ximelagatran (ExantaTM) and BIBR 1048. Both are prodrugs with two protecting groups that are eliminated after absorption from the gastrointestinal tract. Their main active substances, melagatran and BIBR 953, are both potent and selective DTIs. In experimental models of thrombosis, melagatran has been shown to have a shallower dose-response curve than warfarin and, therefore, a better separation between efficacy and bleeding. Oral bioavailability, measured as the plasma concentration of the active metabolite, seems to be higher for ximelagatran (20%) than for BIBR 1048 (estimated to 5%). BIBR 953 has a longer half-life (about 12 h) than does melagatran (3-5 h) after oral administration of BIBR 1048 and ximelagatran, respectively. Both melagatran and BIBR 953 are mainly eliminated via the renal route. The variability of the plasma concentration of melagatran after oral administration of ximelagatran is low. There are no clinically relevant interactions with food or cytochrome P450 metabolized drugs and ximelagatran. In clinical studies, ximelagatran has been administered in a twice-daily fixed-dose regimen without coagulation monitoring. Results of published clinical studies are encouraging, both with regard to efficacy and bleeding. Major indications in Phase III studies with ximelagatran are the prevention of venous thromboembolism (VTE) in hip and knee replacement surgery, treatment and long-term secondary prevention of VTE and prevention of stroke in patients with nonvalvular atrial fibrillation. It is anticipated that with a favourable outcome of the Phase III clinical studies new oral DTIs, with the oral fixed-dose regimen without routine coagulation monitoring, will ease the use of today's anticoagulant therapy.
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Suleymanov OD, Szalony JA, Salyers AK, LaChance RM, Parlow JJ, South MS, Wood RS, Nicholson NS. Pharmacological interruption of acute thrombus formation with minimal hemorrhagic complications by a small molecule tissue factor/factor VIIa inhibitor: comparison to factor Xa and thrombin inhibition in a nonhuman primate thrombosis model. J Pharmacol Exp Ther 2003; 306:1115-21. [PMID: 12829728 DOI: 10.1124/jpet.103.052779] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study was designed to evaluate the antithrombotic efficacy and bleeding propensity of a selective, small-molecule inhibitor of tissue factor/factor VIIa (TF/VIIa) in comparison to small-molecule, selective inhibitors of factor Xa and thrombin in a nonhuman primate model of thrombosis. Acute, spontaneous thrombus formation was induced by electrolytic injury to the intimal surface of a femoral blood vessel, which results in thrombus propagation at the injured site. The TF/FVIIa inhibitor 3-amino-5-[1-[2-([4-[amino(imino)methyl]benzyl]amino)-2-oxoethyl]-3-chloro-5-(isopropylamino)-6-oxo-1,6-dihydropyrazin-2-yl]benzoic acid dihydrochloride (PHA-927F) was fully effective in prevention of thrombosis-induced vessel occlusion at a dose of 400 microg/kg/min, i.v., in the arterial vasculature (femoral artery). Neither the effective dose nor multiples up to 4.4-fold the effective arterial plasma concentration elicited any significant effect on bleeding time or blood loss from either the bleeding time site or the surgical (femoral isolation) site. Small-molecule inhibitors of factor Xa or thrombin were effective arterial antithrombotic agents; however, in contrast to the TF/FVIIa inhibitor, they both elicited substantial increases in bleeding propensity at the effective dose and at multiples of the effective plasma concentration. These data indicate that TF/VIIa inhibition effectively prevented arterial thrombosis with less impact on bleeding parameters than equivalent doses of factor Xa and thrombin inhibitors.
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Affiliation(s)
- Osman D Suleymanov
- Pfizer Corporation, Department of Medicinal and Combinatorial Chemistry, St Louis, MO 63167, USA
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48
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Ries UJ, Priepke HWM, Hauel NH, Handschuh S, Mihm G, Stassen JM, Wienen W, Nar H. Heterocyclic thrombin inhibitors. Part 2: quinoxalinone derivatives as novel, potent antithrombotic agents. Bioorg Med Chem Lett 2003; 13:2297-302. [PMID: 12824021 DOI: 10.1016/s0960-894x(03)00443-8] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Quinoxalinone derivatives as prototypes of dual thrombin and factor Xa inhibitors have been discovered. Nanomolar inhibition of both coagulation enzymes resulted in very potent antithrombotic activity in vitro.
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Affiliation(s)
- Uwe J Ries
- Department of Chemical Research, Boehringer Ingelheim Pharma KG, Birkendorfer Strasse 65, D-88397, Biberach/Riss, Germany.
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Rauh D, Klebe G, Stürzebecher J, Stubbs MT. ZZ made EZ: influence of inhibitor configuration on enzyme selectivity. J Mol Biol 2003; 330:761-70. [PMID: 12850145 DOI: 10.1016/s0022-2836(03)00617-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Selectivity of drug targeting is necessary in order to forestall undesired side-effects. Here, we examine the structural grounds for the configuration-dependent selectivity of 2,7-bis(4-amidinobenzylidene)-cycloheptan-1-one (1) for factor Xa and trypsin: Previous studies showed that factor Xa is preferentially inhibited by the (Z,Z) configuration isomer of (1), whilst trypsin binds equally well to both (E,Z) and (Z,Z) forms. Using engineered trypsin variants, we find similar overall binding modes for the (E,Z) and (Z,Z) isomers. Minor changes in van der Waals' contacts to Tyr99 (Leu in trypsin) explain the differential inhibition of factor Xa. We note differences in the experimental electron densities observed from co-crystallisation and soaking experiments: while the co-crystallisation of (1) with variants containing Tyr99 (Leu99) reveal the exclusive presence of the (Z,Z) ((E,Z)) configurations respectively, soaking experiments with either variant result in mixtures of (E,Z), (Z,Z) and (E,E). This discrepancy arises presumably from differences in the spatial (packing considerations) or chemical (crystallisation conditions) microenvironments. The results presented here represent an extreme example of the problems that face structure-based drug design, in particular the dangers inherent in relying on a single crystal structure for interpreting protein-ligand interactions.
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Affiliation(s)
- Daniel Rauh
- Institut für Pharmazeutische, Chemie der Philipps-Universität Marburg, Marbacher Weg 6, D-35032, Marburg, Germany
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50
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Gustafsson D, Elg M. The pharmacodynamics and pharmacokinetics of the oral direct thrombin inhibitor ximelagatran and its active metabolite melagatran: a mini-review. Thromb Res 2003; 109 Suppl 1:S9-15. [PMID: 12818629 DOI: 10.1016/s0049-3848(03)00249-4] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Ximelagatran (Exanta, AstraZeneca) is a novel, oral direct thrombin inhibitor (oral DTI) that is rapidly converted to melagatran, its active form, following absorption. Melagatran has been shown to be a potent, rapidly binding, competitive inhibitor of human alpha-thrombin that inhibits both thrombin activity and generation. Melagatran also effectively inhibits both free and clot-bound thrombin. Melagatran has a wide therapeutic interval that enables it to be administered safely across a wide range of doses with no increased risk of bleeding, in contrast with warfarin whose narrow therapeutic window necessitates monitoring of its pharmacodynamic effect. Although melagatran has all the pharmacodynamic properties required of a new antithrombotic agent, low oral bioavailability that is even further reduced by the concomitant intake of food precludes its development as an oral agent. It was this that propelled the development of its prodrug, ximelagatran, which is 170 times more lipophilic than melagatran and uncharged at intestinal pH. Ximelagatran is therefore much better than melagatran at penetrating the gastrointestinal barrier and, as a consequence, has sufficient bioavailability (20%) for oral administration. Moreover, its pharmacokinetic properties following oral administration are stable and reproducible, with no food interactions and a low potential for drug-drug interactions. These properties allow ximelagatran to be administered twice daily according to a fixed dose regimen without coagulation monitoring. As a consequence of its favourable pharmacokinetic and pharmacodynamic properties, ximelagatran is currently undergoing full-scale clinical development for the prophylaxis and treatment of thromboembolic disorders.
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Affiliation(s)
- David Gustafsson
- Department of Cardiovascular Pharmacology, AstraZeneca R&D, Mölndal, S-431 83 Mölndal, Sweden.
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