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Guzzardo GM, Sidonio R, Callaghan MU, Regling K. Early stage clinical trials for the treatment of hemophilia A. Expert Opin Investig Drugs 2022; 31:1169-1186. [PMID: 36265129 DOI: 10.1080/13543784.2022.2138742] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
INTRODUCTION Hemophilia A is a severe bleeding disorder affecting about 1 in 5,000 males. The gold standard for prophylaxis and treatment of acute bleeding has been factor (F) VIII concentrate. A multitude of treatment modalities are now available and under clinical investigation. AREAS COVERED This review discusses ongoing/recently completed early-phase clinical trials registered on ClinicalTrials.gov in patients with hemophilia A through April 2022. These new pipeline therapies are focused on addressing the safety and efficacy of new factor-related products, non-factor related products, and gene therapy options for hemophilia. EXPERT OPINION Current standard of care effectively prevents and treats acute bleeding and has significantly improved the quality of life in hemophilia. The biggest challenges in the improvement of care are treatment-related burden and the burden of cost in developing countries. New drugs under development are likely to enter practice by the end of this decade and address many of the unmet needs particularly of those with severe disease. Data is limited in unique populations (e.g. congenital/inherited FVIII inhibitors, non-severe hemophilia A, women/girls with hemophilia and children) which are important areas for future research; additional clinical trials and long-term outcome data are necessary prior to incorporating these new therapies in our treatment arsenal.
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Affiliation(s)
- Gianna M Guzzardo
- Pediatric Hematology Oncology, Children's Hospital of Michigan, Detroit, MI, USA
| | - Robert Sidonio
- Pediatric Hematology Oncology, Emory University and Aflac Cancer and Blood Disorders, Atlanta, GA, USA
| | - Michael U Callaghan
- Agios Pharmaceuticals, Cambridge, MA, USA.,Department of Pediatrics, Central Michigan University School of Medicine, Mount Pleasant, MI, USA
| | - Katherine Regling
- Pediatric Hematology Oncology, Children's Hospital of Michigan, Detroit, MI, USA.,Department of Pediatrics, Central Michigan University School of Medicine, Mount Pleasant, MI, USA
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Subcutaneous concizumab prophylaxis in hemophilia A and hemophilia A/B with inhibitors: phase 2 trial results. Blood 2020; 134:1973-1982. [PMID: 31444162 DOI: 10.1182/blood.2019001542] [Citation(s) in RCA: 83] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 08/06/2019] [Indexed: 11/20/2022] Open
Abstract
Results from the main parts (24 weeks) of 2 concizumab phase 2 trials are presented: explorer4 in hemophilia A (HA) or B (HB) with inhibitors (HAwI/HBwI) and explorer5 in HA. The trials aimed to evaluate the efficacy of daily subcutaneous concizumab prophylaxis (evaluated as annualized bleeding rate [ABR] at last dose level), with secondary objectives being safety and immunogenicity (assessed as number of adverse events [AEs] and antidrug antibodies [ADAs]). Patients received 0.15 mg/kg concizumab, with potential dose escalation to 0.20 and 0.25 mg/kg (if ≥3 spontaneous bleeding episodes within 12 weeks of concizumab treatment). Relevant pharmacokinetic/pharmacodynamic (PK/PD) parameters were assessed. Thirty-six HA, 9 HAwI, and 8 HBwI patients were exposed to concizumab. Most inhibitor patients (15 of 17; 88.2%) did not escalate the dose; all patients chose to continue to the extension phase of the trials. Clinical proof of concept for prevention of bleeding episodes was demonstrated in both trials. Estimated ABRs in HAwI and HBwI were lower vs HA: 3.0 (95% confidence interval [CI], 1.7; 5.3) and 5.9 (95% CI, 4.2; 8.5) vs 7.0 (95% CI, 4.6; 10.7), respectively. PK/PD results were as expected, with no difference between hemophilia subtypes for concizumab exposure, free tissue factor pathway inhibitor, thrombin generation, prothrombin fragment 1+2, and d-dimers. Concizumab was safe and well tolerated (no severe AEs, AE-related withdrawals, or thromboembolic events). Three patients had (very low to medium titer) ADA+ tests in each trial, with no observed clinical effect. These results support further development of concizumab as a daily prophylactic treatment in all hemophilia patients. These trials were registered at www.clinicaltrials.gov as #NCT03196284 and #NCT03196297.
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Eichler H, Angchaisuksiri P, Kavakli K, Knoebl P, Windyga J, Jiménez-Yuste V, Harder Delff P, Chowdary P. Concizumab restores thrombin generation potential in patients with haemophilia: Pharmacokinetic/pharmacodynamic modelling results of concizumab phase 1/1b data. Haemophilia 2018; 25:60-66. [PMID: 30408848 PMCID: PMC7379180 DOI: 10.1111/hae.13627] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 10/04/2018] [Accepted: 10/04/2018] [Indexed: 01/18/2023]
Abstract
Introduction Concizumab enhances thrombin generation (TG) potential in haemophilia patients by inhibiting tissue factor pathway inhibitor (TFPI). In EXPLORER3 (phase 1b), a dose‐dependent pharmacokinetic/pharmacodynamic (PK/PD) relationship was confirmed between concizumab dose, free TFPI and TG potential. Aim Determine the association between concizumab exposure, PD markers (free TFPI; peak TG) and bleeding episodes to establish the minimum concizumab concentration for achieving sufficient efficacy. Methods Free TFPI predictions were generated using an estimated concizumab‐free TFPI exposure‐response (Emax) model based on concizumab phase 1/1b data for which simultaneously collected concizumab and free TFPI samples were available. Concizumab concentration at the time of a bleed was predicted using a PK model, based on available data for concizumab doses >50 μg/kg to ≤9 mg/kg. Peak TG vs concizumab concentration analyses and an Emax model were constructed based on EXPLORER3 observations. Results The Emax model showed a tight PK/PD relationship between concizumab exposure and free TFPI; free TFPI decreased with increasing concizumab concentration. A strong correlation between concizumab concentration and peak TG was observed; concizumab >100 ng/mL re‐established TG potential to within the normal reference range. Estimated EC50 values for the identified concizumab‐free TFPI and concizumab‐TG potential models were very similar, supporting free TFPI as an important biomarker. A correlation between bleeding episode frequency and concizumab concentration was indicated; patients with a concizumab concentration >100 ng/mL experienced less frequent bleeding. The PK model predicted that once‐daily dosing would minimize within‐patient concizumab PK variability. Conclusion Concizumab phase 2 trials will target an exposure ≥100 ng/mL, with a once‐daily regimen.
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Affiliation(s)
- Hermann Eichler
- Institute of Clinical Hemostaseology and Transfusion Medicine, Saarland University and University Hospital, Homburg/Saar, Germany
| | - Pantep Angchaisuksiri
- Division of Hematology, Department of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Kaan Kavakli
- Department of Hematology, Ege University Children's Hospital, Izmir, Turkey
| | - Paul Knoebl
- Clinical Division of Hematology and Hemostasis, Medical University of Vienna, Vienna, Austria
| | - Jerzy Windyga
- Department of Disorders of Hemostasis and Internal Medicine, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
| | | | | | - Pratima Chowdary
- Katharine Dormandy Haemophilia Centre and Thrombosis Unit, Royal Free London NHS Foundation Trust, London, UK
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Eichler H, Angchaisuksiri P, Kavakli K, Knoebl P, Windyga J, Jiménez-Yuste V, Hyseni A, Friedrich U, Chowdary P. A randomized trial of safety, pharmacokinetics and pharmacodynamics of concizumab in people with hemophilia A. J Thromb Haemost 2018; 16:2184-2195. [PMID: 30137664 DOI: 10.1111/jth.14272] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Indexed: 01/22/2023]
Abstract
Essentials explorer™3 was a double-blinded, multiple-dose escalation trial of subcutaneous concizumab. A pharmacodynamic relationship for unbound TFPI and thrombin generation was confirmed. No serious adverse events and no anti-drug antibodies were observed. explorer™3 data support further clinical development of concizumab in people with hemophilia. SUMMARY: Background Concizumab is a humanized mAb targeting tissue factor pathway inhibitor (TFPI), leading to enhanced thrombin generation (TG) potential. explorer™3 (NCT02490787) was a phase 1b, double-blind, multiple-dose escalation trial of subcutaneous concizumab in people with severe hemophilia A without inhibitors. Objectives The primary objective was to evaluate safety. Assessments of pharmacokinetics, pharmacodynamics and subcutaneous concizumab immunogenicity were secondary objectives. Patients/Methods Adverse events (AEs), clinical assessments and bleeding episodes were recorded. Plasma concizumab levels and unbound TFPI levels were measured with ELISAs; residual TFPI activity was measured with a chromogenic assay. Standardized assays were used to assess TG, D-dimer and prothrombin fragment 1 + 2 (F1 + 2 ) levels. explorer™3 was completed after investigation of three dose cohorts (0.25, 0.5 and 0.8 mg kg-1 , once every 4 days) had been completed. Twenty-four patients received 12 doses of concizumab or placebo in a 3 : 1 randomization over a 42-day period. Results No serious AEs and no anti-drug antibodies were observed. Fifty-four mild and two moderate AEs were observed in 19 patients. Concizumab exposure increased with dose in a non-linear manner, confirming target-mediated drug disposition. D-dimer and F1 + 2 levels were increased mostly in the highest dose cohort, in line with previous observations. The level of unbound TFPI decreased in a dose-dependent manner, and was accompanied by a residual TFPI activity decrease and an increase in peak TG. Although the trial was not powered to evaluate efficacy, a trend towards lower bleeding rates was observed in patients in the highest dose cohort. Conclusion explorer™3 data support further clinical development of concizumab for use in people with hemophilia, with or without inhibitors.
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Affiliation(s)
- H Eichler
- Institute of Clinical Hemostaseology and Transfusion Medicine, Saarland University and University Hospital, Homburg/Saar, Germany
| | - P Angchaisuksiri
- Division of Hematology, Department of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - K Kavakli
- Department of Hematology, Ege University Children's Hospital, Izmir, Turkey
| | - P Knoebl
- Department of Medicine 1, Division of Hematology and Hemostasis, Medical University of Vienna, Vienna, Austria
| | - J Windyga
- Department of Disorders of Hemostasis and Internal Medicine, Institute of Hematology and Transfusion Medicine, Warsaw, Poland
| | - V Jiménez-Yuste
- Hematology Department, La Paz University Hospital, Madrid, Spain
| | - A Hyseni
- Research and Development, Novo Nordisk A/S, Copenhagen, Denmark
| | - U Friedrich
- Research and Development, Novo Nordisk A/S, Copenhagen, Denmark
| | - P Chowdary
- Katharine Dormandy Haemophilia Centre and Thrombosis Unit, Royal Free London NHS Foundation Trust, London, UK
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Giansily-Blaizot M, Schved JF. Recombinant human factor VIIa (rFVIIa) in hemophilia: mode of action and evidence to date. Ther Adv Hematol 2017; 8:345-352. [PMID: 29204261 DOI: 10.1177/2040620717737701] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 09/11/2017] [Indexed: 11/17/2022] Open
Abstract
Recombinant activated factor VII (rFVIIa) is a bypassing agent widely used both in the treatment and prevention of hemorrhagic complications due to hemophilia with inhibitor. In such cases, antihemophilic factors cannot be used. The normal physiology of factor VII/ factor VIIa (FVII/FVIIa) in the hemostatic process requires the presence of tissue factor (TF) that links to FVII leading to a FVIIa-TF complex which activates both factor X and factor IX. The therapeutic use of rFVIIa requires high amount of FVIIa. Some studies demonstrate that FVIIa at high doses still requires tissue factor for function, whereas others suggest that FVIIa activates FX directly on the platelet surface, in a TF-independent manner. In the present article, we discuss the arguments supporting both TF-dependent and TF-independent modes of action. Finally, the coexistence of both TF-dependent and TF-independent mechanisms cannot be excluded.
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Affiliation(s)
| | - Jean-François Schved
- Hemophilia Treatment Centre, Hôpital Saint-Eloi, CHU Montpellier, 80 avenue A Fliche, 34295 Montpellier Cedex 5, France
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Management of the Jehovah's Witness in Obstetrics and Gynecology: A Comprehensive Medical, Ethical, and Legal Approach. Obstet Gynecol Surv 2017; 71:488-500. [PMID: 27526872 DOI: 10.1097/ogx.0000000000000343] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
IMPORTANCE Obstetricians and gynecologists frequently deal with hemorrhage so they should be familiar with management of patients who refuse blood transfusion. Although there are some reports in the literature about management of Jehovah's Witness patients in obstetrics and gynecology, most of them are case reports, and a comprehensive review about these patients including ethicolegal perspective is lacking. OBJECTIVE This review outlines the medical, ethical, and legal implications of management of Jehovah's Witness patients in obstetrical and gynecological settings. EVIDENCE ACQUISITION A search of published literature using PubMed, Ovid Medline, EMBASE, and Cochrane databases was conducted about physiology of oxygen delivery and response to tissue hypoxia, mortality rates at certain hemoglobin levels, medical management options for anemic patients who refuse blood transfusion, and ethical/legal considerations in Jehovah's Witness patients. RESULTS Early diagnosis of anemia and immediate initiation of therapy are essential in patients who refuse blood transfusion. Medical management options include iron supplementation and erythropoietin. There are also some promising therapies that are in development such as antihepcidin antibodies and hemoglobin-based oxygen carriers. Options to decrease blood loss include antifibrinolytics, desmopressin, recombinant factor VII, and factor concentrates. When surgery is the only option, every effort should be made to pursue minimally invasive approaches. CONCLUSION AND RELEVANCE All obstetricians and gynecologists should be familiar with alternatives and "less invasive" options for patients who refuse blood transfusions.
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Grandoni J, Perret G, Forier C. Kinetic analysis and binding studies of a new recombinant human factor VIIa for treatment of haemophilia. Haemophilia 2016; 23:300-308. [PMID: 27995727 DOI: 10.1111/hae.13110] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/30/2016] [Indexed: 11/30/2022]
Abstract
INTRODUCTION/AIM LR769 is a new second-generation recombinant human Factor VIIa (rhFVIIa) developed for haemophilia treatment. We determined enzymatic properties of LR769 and its interaction with antithrombin, tissue factor, platelets and endothelial protein C receptor (EPCR), compared with NovoSevenRT. METHODS Kinetic enzyme assays and active site titration were used for enzymatic studies. Surface Plasmon Resonance (SPR) was used for determination of binding constants. Cellular binding was determined for platelets and cultured human umbilical vein endothelial cells (HUVEC). RESULTS The dissociation constant (Kd ) for activated platelet binding was in the 1 μm range for both products. At saturation, more LR769 than NovoSevenRT was bound to the platelets. Binding to HUVEC was 25-50% higher for LR769 than for NovoSevenRT. Protein C, soluble EPCR, and anti-EPCR antibody all reduced the binding, indicating specificity for EPCR. LR769 was similar to NovoSevenRT in all kinetic assays. Active site titration demonstrated 0.7 mole of active site/mole of protein. The kcat /Km values for activation of FX and FIX with purified recombinant tissue factor and phospholipids were 10.5 s-1 /0.32 μm and 3.3 s-1 /0.44 μm respectively. The apparent second-order rate constant for inactivation by human plasma AT was 5.9 ± 0.4 × 103 m-1 s-1 . The Kd values for binding of LR769 to soluble tissue factor and full-length tissue factor were 8.1 nm and 0.9 nm, respectively, and the Kd for binding to soluble EPCR was 41 nm. CONCLUSION Overall, LR769 exhibited characteristics similar to NovoSevenRT, but bound EPCR on HUVEC with somewhat higher affinity than NovoSevenRT.
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Exactin: A specific inhibitor of Factor X activation by extrinsic tenase complex from the venom of Hemachatus haemachatus. Sci Rep 2016; 6:32036. [PMID: 27558950 PMCID: PMC4997346 DOI: 10.1038/srep32036] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 08/02/2016] [Indexed: 11/17/2022] Open
Abstract
Unwanted clots lead to heart attack and stroke that result in a large number of deaths. Currently available anticoagulants have some drawbacks including their non-specific actions. Therefore novel anticoagulants that target specific steps in the coagulation pathway are being sought. Here we describe the identification and characterization of a novel anticoagulant protein from the venom of Hemachatus haemachatus (African Ringhals cobra) that specifically inhibits factor X (FX) activation by the extrinsic tenase complex (ETC) and thus named as exactin. Exactin belongs to the three-finger toxin (3FTx) family, with high sequence identity to neurotoxins and low identity to the well-characterized 3FTx anticoagulants-hemextin and naniproin. It is a mixed-type inhibitor of ETC with the kinetic constants, Ki’ and Ki determined as 30.62 ± 7.73 nM and 153.75 ± 17.96 nM, respectively. Exactin does not bind to the active site of factor VIIa and factor Xa based on its weak inhibition (IC50 ≫ 300 μM) to the amidolytic activities of these proteases. Exactin shows exquisite macromolecular specificity to FX activation as compared to factor IX activation by ETC. Exactin thus displays a distinct mechanism when compared to other anticoagulants targeting ETC, with its selective preference to ETC-FX [ES] complex.
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Barnwal B, Jobichen C, Girish VM, Foo CS, Sivaraman J, Kini RM. Ringhalexin from Hemachatus haemachatus: A novel inhibitor of extrinsic tenase complex. Sci Rep 2016; 6:25935. [PMID: 27173146 PMCID: PMC4865804 DOI: 10.1038/srep25935] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 04/26/2016] [Indexed: 12/15/2022] Open
Abstract
Anticoagulant therapy is used for the prevention and treatment of thromboembolic disorders. Blood coagulation is initiated by the interaction of factor VIIa (FVIIa) with membrane-bound tissue factor (TF) to form the extrinsic tenase complex which activates FX to FXa. Thus, it is an important target for the development of novel anticoagulants. Here, we report the isolation and characterization of a novel anticoagulant ringhalexin from the venom of Hemachatus haemachatus (African Ringhals Cobra). Amino acid sequence of the protein indicates that it belongs to the three-finger toxin family and exhibits 94% identity to an uncharacterized Neurotoxin-like protein NTL2 from Naja atra. Ringhalexin inhibited FX activation by extrinsic tenase complex with an IC50 of 123.8 ± 9.54 nM. It is a mixed-type inhibitor with the kinetic constants, Ki and Ki' of 84.25 ± 3.53 nM and 152.5 ± 11.32 nM, respectively. Ringhalexin also exhibits a weak, irreversible neurotoxicity on chick biventer cervicis muscle preparations. Subsequently, the three-dimensional structure of ringhalexin was determined at 2.95 Å resolution. This study for the first time reports the structure of an anticoagulant three-finger toxin. Thus, ringhalexin is a potent inhibitor of the FX activation by extrinsic tenase complex and a weak, irreversible neurotoxin.
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Affiliation(s)
- Bhaskar Barnwal
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore 119260, Singapore
| | - Chacko Jobichen
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore 119260, Singapore
| | | | - Chun Shin Foo
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore 119260, Singapore
| | - J. Sivaraman
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore 119260, Singapore
| | - R. Manjunatha Kini
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore 119260, Singapore
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Safety and efficacy of recombinant activated factor VII in nonhemophilia children with severe or life-threatening bleeding: a report from the SeveNBleeP registry. Blood Coagul Fibrinolysis 2015; 25:326-32. [PMID: 24389586 DOI: 10.1097/mbc.0000000000000036] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We evaluated efficacy and safety of recombinant activated factor VII (rFVIIa) in nonhemophilia children with life-threatening or severe bleeding. Using data from the SeveNBleeP registry, we analyzed demographic, clinical, laboratory, and treatment data for children who received rFVIIa to treat severe hemorrhage. The SeveNBleeP registry was international registry formed in 2005, to collect information on the use of rFVIIa in the off-label setting of severe bleeding in nonhemophilia patients. There were 191 patient records entered into this registry, of which 164 were validated. Of the 164 records, in 137 patient records, rFVIIa was used for treatment of bleeding episodes. Of these 137 treatment episodes, 42 were in neonates and infants under 1 year of age. Use of rFVIIa significantly improved laboratory parameters (prothrombin time, international normalized ratio, activated partial thromboplastin time, hematocrit), reduced estimated blood loss, and reduced requirements for blood products (packed red blood cells and fresh frozen plasma) in those more than 1 year of age. There was no significant reduction in requirements for blood products after rFVIIa administration in the neonates and infants, but there was a trend to lower frequency of FFP use after rFVIIa administration. There was one thromboembolic event in an infant that was related to administration of rFVIIa. No other serious adverse events were reported that were related to administration of rFVIIa. In nonhemophilia-associated bleeding in children, rFVIIa appears to be safe and efficacious in reducing estimated blood loss in children over 1 year of age, although its effectiveness in infants below 1 year of age was less clear.
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Shibeko AM, Panteleev MA. Untangling the complexity of blood coagulation network: use of computational modelling in pharmacology and diagnostics. Brief Bioinform 2015; 17:429-39. [DOI: 10.1093/bib/bbv040] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Indexed: 01/22/2023] Open
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Shetty S, Ghosh K. Novel therapeutic approaches for haemophilia. Haemophilia 2014; 21:152-161. [DOI: 10.1111/hae.12615] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/22/2014] [Indexed: 01/11/2023]
Affiliation(s)
- S. Shetty
- Department of Thrombosis and Haemostasis National Institute of Immunohaematology (ICMR) KEM Hospital Mumbai India
| | - K. Ghosh
- Department of Thrombosis and Haemostasis National Institute of Immunohaematology (ICMR) KEM Hospital Mumbai India
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Shapiro AD, Hedner U. Advances in bypassing agent therapy for hemophilia patients with inhibitors to close care gaps and improve outcomes. Ther Adv Drug Saf 2014; 2:213-25. [PMID: 25083214 DOI: 10.1177/2042098611415566] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
In the past, patients with hemophilia and inhibitors have had less-than-optimal treatment and have experienced more orthopedic complications than patients without inhibitors. Bypassing agents offer the potential to close treatment gaps between inhibitor and noninhibitor patients by helping the former better attain key treatment goals, including: facilitating early initiation of treatment and hemostatic control in hemarthroses; providing effective treatment in serious hemorrhagic episodes; and performance of major surgery. Effective treatment with a bypassing agent minimizes joint and/or muscle damage and potentially can serve as an effective prophylactic agent to minimize the number of hemarthroses experienced per year, thereby mitigating the development of arthropathy. The reported efficacy of the currently available bypassing agents ranges from approximately 50-80% (50-64% in controlled studies) for plasma-derived activated prothrombin complex concentrate (pd-aPCC) and 81-91% (in controlled studies) for recombinant activated factor VII (rFVIIa), including use in major orthopedic surgery. Both bypassing agents have undergone key improvements in their formulation and/or properties in recent years. The nanofiltered, vapor-heated formulation of pd-aPCC has diminished the risk of acquiring blood-borne viral infections and the room temperature stable formulation of rFVIIa allows more convenient storage, increased ease to dissolve and inject, and smaller volumes, thereby increasing overall ease of administration. Use of recommended dosing has been demonstrated to provide effective hemostasis with a minimal number of injections for both agents. In this paper, we review the individual characteristics of pd-aPCC and rFVIIa and discuss clinical data from studies conducted in inhibitor patients that demonstrate the potential benefits of these bypassing agents in this difficult-to-treat population, and underscore the potential opportunities to close the gap in care between inhibitor and noninhibitor hemophilic patients.
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Affiliation(s)
- Amy D Shapiro
- Indiana Hemophilia and Thrombosis Center, 8402 Harcourt Road, Suite 500, Indianapolis, IN 46260, USA
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Chaterji S, Lam CH, Ho DS, Proske DC, Baker AB. Syndecan-1 regulates vascular smooth muscle cell phenotype. PLoS One 2014; 9:e89824. [PMID: 24587062 PMCID: PMC3934950 DOI: 10.1371/journal.pone.0089824] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2013] [Accepted: 01/24/2014] [Indexed: 12/21/2022] Open
Abstract
OBJECTIVE We examined the role of syndecan-1 in modulating the phenotype of vascular smooth muscle cells in the context of endogenous inflammatory factors and altered microenvironments that occur in disease or injury-induced vascular remodeling. METHODS AND RESULTS Vascular smooth muscle cells (vSMCs) display a continuum of phenotypes that can be altered during vascular remodeling. While the syndecans have emerged as powerful and complex regulators of cell function, their role in controlling vSMC phenotype is unknown. Here, we isolated vSMCs from wild type (WT) and syndecan-1 knockout (S1KO) mice. Gene expression and western blotting studies indicated decreased levels of α-smooth muscle actin (α-SMA), calponin, and other vSMC-specific differentiation markers in S1KO relative to WT cells. The spread area of the S1KO cells was found to be greater than WT cells, with a corresponding increase in focal adhesion formation, Src phosphorylation, and alterations in actin cytoskeletal arrangement. In addition, S1KO led to increased S6RP phosphorylation and decreased AKT and PKC-α phosphorylation. To examine whether these changes were present in vivo, isolated aortae from aged WT and S1KO mice were stained for calponin. Consistent with our in-vitro findings, the WT mice aortae stained higher for calponin relative to S1KO. When exposed to the inflammatory cytokine TNF-α, WT vSMCs had an 80% reduction in syndecan-1 expression. Further, with TNF-α, S1KO vSMCs produced increased pro-inflammatory cytokines relative to WT. Finally, inhibition of interactions between syndecan-1 and integrins αvβ3 and αvβ5 using the inhibitory peptide synstatin appeared to have similar effects on vSMCs as knocking out syndecan-1, with decreased expression of vSMC differentiation markers and increased expression of inflammatory cytokines, receptors, and osteopontin. CONCLUSIONS Taken together, our results support that syndecan-1 promotes vSMC differentiation and quiescence. Thus, the presence of syndecan-1 would have a protective effect against vSMC dedifferentiation and this activity is linked to interactions with integrins αvβ3 and αvβ5.
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Affiliation(s)
- Somali Chaterji
- Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas, United States of America
| | - Christoffer H. Lam
- Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas, United States of America
| | - Derek S. Ho
- Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas, United States of America
| | - Daniel C. Proske
- Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas, United States of America
| | - Aaron B. Baker
- Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas, United States of America
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Agersø H, Overgaard RV, Petersen MB, Hansen L, Hermit MB, Sørensen MH, Petersen LC, Hilden I. Pharmacokinetics of an anti-TFPI monoclonal antibody (concizumab) blocking the TFPI interaction with the active site of FXa in Cynomolgus monkeys after iv and sc administration. Eur J Pharm Sci 2014; 56:65-9. [PMID: 24568891 DOI: 10.1016/j.ejps.2014.02.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2013] [Revised: 01/22/2014] [Accepted: 02/17/2014] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Concizumab (mAb 2021) is a monoclonal IgG4 antibody (mAb) that binds to the Kunitz-type protease inhibitor (KPI) 2 domain of TFPI thereby blocking the interaction of this domain with the active site of FXa. The objective of the present study was to characterize the pharmacokinetics of concizumab in Cynomolgus monkeys after intravenous (iv) and subcutaneous (sc) administration. METHODS Data from two studies were included in the modelling, all in all data from 52 monkeys distributed into 9 groups. Three groups received three escalating sc doses of concizumab with a one week dosing interval, two groups were administered a single dose, and four groups received multiple doses over 13 weeks of concizumab. The plasma concentration was measured using a standard ELISA, and pharmacokinetic data were analysed using NONMEM. RESULTS The pharmacokinetics of concizumab were characterised by a high bioavailability (93%) after sc administration. The time course of the elimination of concizumab from the circulation was well described by the proposed target mediated drug disposition (TMDD) model. The clearance of concizumab was estimated to be 0.14 ml/h/kg, the target clearance was characterized by a 50% saturation level of 0.54 μg/ml (Km), and the clearance at target saturation was estimated to be 11 μg/h/kg. CONCLUSION Concizumab displays a typical TMDD profile with important implications for a putative treatment regime in haemophilia patients. Compared to current standard haemophilia treatment, concizumab has a high bioavailability after sc administration and may provide a viable alternative to intravenous dosing for the treatment of haemophilia.
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Affiliation(s)
- Henrik Agersø
- Research and Development, Novo Nordisk A/S, Denmark.
| | | | | | - Lene Hansen
- Research and Development, Novo Nordisk A/S, Denmark
| | | | | | | | - Ida Hilden
- Research and Development, Novo Nordisk A/S, Denmark
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Jones CM, Baker-Groberg SM, Cianchetti FA, Glynn JJ, Healy LD, Lam WY, Nelson JW, Parrish DC, Phillips KG, Scott-Drechsel DE, Tagge IJ, Zelaya JE, Hinds MT, McCarty OJT. Measurement science in the circulatory system. Cell Mol Bioeng 2013; 7:1-14. [PMID: 24563678 DOI: 10.1007/s12195-013-0317-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The dynamics of the cellular and molecular constituents of the circulatory system are regulated by the biophysical properties of the heart, vasculature and blood cells and proteins. In this review, we discuss measurement techniques that have been developed to characterize the physical and mechanical parameters of the circulatory system across length scales ranging from the tissue scale (centimeter) to the molecular scale (nanometer) and time scales of years to milliseconds. We compare the utility of measurement techniques as a function of spatial resolution and penetration depth from both a diagnostic and research perspective. Together, this review provides an overview of the utility of measurement science techniques to study the spatial systems of the circulatory system in health and disease.
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Affiliation(s)
- Casey M Jones
- Department of Biomedical Engineering, Oregon Health & Science University, Portland OR ; Department of Chemistry, Lewis & Clark College, Portland OR
| | | | - Flor A Cianchetti
- Department of Biomedical Engineering, Oregon Health & Science University, Portland OR
| | - Jeremy J Glynn
- Department of Biomedical Engineering, Oregon Health & Science University, Portland OR
| | - Laura D Healy
- Department of Cell & Developmental Biology, Oregon Health & Science University, Portland OR
| | - Wai Yan Lam
- Department of Biomedical Engineering, Oregon Health & Science University, Portland OR
| | - Jonathan W Nelson
- Division of Cardiology, Knight Cardiovascular Institute, Oregon Health & Science University, Portland OR
| | - Diana C Parrish
- Department of Physiology & Pharmacology, Oregon Health & Science University, Portland OR
| | - Kevin G Phillips
- Department of Biomedical Engineering, Oregon Health & Science University, Portland OR
| | | | - Ian J Tagge
- Department of Biomedical Engineering, Oregon Health & Science University, Portland OR ; Advanced Imaging Research Center, Oregon Health & Science University, Portland OR
| | - Jaime E Zelaya
- Department of Biomedical Engineering, Oregon Health & Science University, Portland OR
| | - Monica T Hinds
- Department of Biomedical Engineering, Oregon Health & Science University, Portland OR
| | - Owen J T McCarty
- Department of Biomedical Engineering, Oregon Health & Science University, Portland OR ; Department of Cell & Developmental Biology, Oregon Health & Science University, Portland OR ; Division of Hematology & Medical Oncology, Oregon Health & Science University, Portland OR
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Dockal M, Hartmann R, Fries M, Thomassen MCLGD, Heinzmann A, Ehrlich H, Rosing J, Osterkamp F, Polakowski T, Reineke U, Griessner A, Brandstetter H, Scheiflinger F. Small peptides blocking inhibition of factor Xa and tissue factor-factor VIIa by tissue factor pathway inhibitor (TFPI). J Biol Chem 2013; 289:1732-41. [PMID: 24275667 DOI: 10.1074/jbc.m113.533836] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Tissue factor pathway inhibitor (TFPI) is a Kunitz-type protease inhibitor that inhibits activated factor X (FXa) via a slow-tight binding mechanism and tissue factor-activated FVII (TF-FVIIa) via formation of a quaternary FXa-TFPI-TF-FVIIa complex. Inhibition of TFPI enhances coagulation in hemophilia models. Using a library approach, we selected and subsequently optimized peptides that bind TFPI and block its anticoagulant activity. One peptide (termed compound 3), bound with high affinity to the Kunitz-1 (K1) domain of TFPI (Kd ∼1 nM). We solved the crystal structure of this peptide in complex with the K1 of TFPI at 2.55-Å resolution. The structure of compound 3 can be segmented into a N-terminal anchor; an Ω-shaped loop; an intermediate segment; a tight glycine-loop; and a C-terminal α-helix that is anchored to K1 at its reactive center loop and two-stranded β-sheet. The contact surface has an overall hydrophobic character with some charged hot spots. In a model system, compound 3 blocked FXa inhibition by TFPI (EC50 = 11 nM) and inhibition of TF-FVIIa-catalyzed FX activation by TFPI (EC50 = 2 nM). The peptide prevented transition from the loose to the tight FXa-TFPI complex, but did not affect formation of the loose FXa-TFPI complex. The K1 domain of TFPI binds and inhibits FVIIa and the K2 domain similarly inhibits FXa. Because compound 3 binds to K1, our data show that K1 is not only important for FVIIa inhibition but also for FXa inhibition, i.e. for the transition of the loose to the tight FXa-TFPI complex. This mode of action translates into normalization of coagulation of hemophilia plasmas. Compound 3 thus bears potential to prevent bleeding in hemophilia patients.
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Affiliation(s)
- Michael Dockal
- From Baxter Innovations GmbH, Uferstrasse 15, A-2304 Orth/Donau, Austria
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Clark CA, Vatsyayan R, Hedner U, Esmon CT, Pendurthi UR, Rao LVM. Endothelial cell protein C receptor-mediated redistribution and tissue-level accumulation of factor VIIa. J Thromb Haemost 2012; 10:2383-91. [PMID: 22950420 PMCID: PMC3528836 DOI: 10.1111/j.1538-7836.2012.04917.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Accepted: 08/30/2012] [Indexed: 11/27/2022]
Abstract
BACKGROUND Recent studies show that activated factor VII (FVIIa) binds to the endothelial cell protein C receptor (EPCR) on the vascular endothelium; however, the importance of this interaction in hemostasis or pathophysiology is unknown. OBJECTIVE The aim of the present study was to investigate the role of the FVIIa interaction with EPCR on the endothelium in mediating FVIIa transport from the circulation to extravascular tissues. METHODS Wild-type, EPCR-deficient or ECPR-over-expressing mice were injected with human recombinant (r)FVIIa (120 μg kg(-1) body weight) via the tail vein. At varying time intervals after rFVIIa administration, blood and various tissues were collected to measure FVIIa antigen and activity levels. Tissue sections were analyzed by immunohistochemistry for FVIIa and EPCR. RESULTS The data reveal that, after intravenous (i.v.) injection, rFVIIa rapidly disappears from the blood and associates with the endothelium in an EPCR-dependent manner. Immunohistochemical analyses revealed that the association of FVIIa with the endothelium was maximal at 30 min and thereafter progressively declined. The FVIIa association with the endothelium was undetectable at time points exceeding 24 h post-FVIIa administration. The levels of rFVIIa accumulated in tissue correlate with expression levels of EPCR in mice and FVIIa associated with tissues remained functionally active for periods of at least 7 days. CONCLUSIONS The observation that an EPCR-dependent association of FVIIa with the endothelium is most pronounced soon after rFVIIa administration and subsequently declines temporally, combined with the retention of functionally active FVIIa in tissue homogenates for extended periods, indicates that FVIIa binding to EPCR on the endothelium facilitates the transport of FVIIa from circulation to extravascular tissues where TF resides.
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Affiliation(s)
- C A Clark
- Department of Cellular and Molecular Biology, Center for Biomedical Research, The University of Texas Health Science Center at Tyler, Tyler, TX, USA Department of Medicine, Malmö University Hospital, University of Lund, Malmö, Sweden Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Howard Hughes Medical Institute, Oklahoma City, OK, USA
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Camire RM. Bioengineered factor Xa as a potential new strategy for hemophilia therapy. Expert Rev Hematol 2012; 5:121-3. [PMID: 22475278 DOI: 10.1586/ehm.12.13] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Unifying the mechanism of recombinant FVIIa action: dose dependence is regulated differently by tissue factor and phospholipids. Blood 2012; 120:891-9. [PMID: 22563088 DOI: 10.1182/blood-2011-11-393371] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Recombinant factor VIIa (rFVIIa) is used for treatment of hemophilia patients with inhibitors, as well for off-label treatment of severe bleeding in trauma and surgery. Effective bleeding control requires supraphysiological doses of rFVIIa, posing both high expense and uncertain thrombotic risk. Two major competing theories offer different explanations for the supraphysiological rFVIIa dosing requirement: (1) the need to overcome competition between FVIIa and FVII zymogen for tissue factor (TF) binding, and (2) a high-dose-requiring phospholipid-related pathway of FVIIa action. In the present study, we found experimental conditions in which both mechanisms contribute simultaneously and independently to rFVIIa-driven thrombin generation in FVII-deficient human plasma. From mathematical simulations of our model of FX activation, which were confirmed by thrombin-generation experiments, we conclude that the action of rFVIIa at pharmacologic doses is dominated by the TF-dependent pathway with a minor contribution from a phospholipid-dependent mechanism. We established a dose-response curve for rFVIIa that is useful to explain dosing strategies. In the present study, we present a pathway to reconcile the 2 major mechanisms of rFVIIa action, a necessary step to understanding future dose optimization and evaluation of new rFVIIa analogs currently under development.
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Lopez-Vilchez I, Hedner U, Altisent C, Diaz-Ricart M, Escolar G, Galan AM. Redistribution and hemostatic action of recombinant activated factor VII associated with platelets. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 178:2938-48. [PMID: 21641410 DOI: 10.1016/j.ajpath.2011.02.026] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Revised: 02/07/2011] [Accepted: 02/23/2011] [Indexed: 11/30/2022]
Abstract
Clinical evidence accumulated from hemophilic patients during prophylaxis with recombinant activated factor VII (rFVIIa) suggests that the duration of the hemostatic action of rFVIIa exceeds its predicted plasma half-life. Mechanisms involved in this outcome have not been elucidated. We have investigated in vitro the redistribution of rFVIIa in platelets from healthy donors, patients with FVII deficiency, and one patient with Bernard-Soulier syndrome. Platelet-rich plasma was exposed to rFVIIa (3 to 60 μg/mL). Flow cytometry, immunocytochemistry, and coagulation tests were applied to detect and quantify rFVIIa. The hemostatic effect of rFVIIa associated to platelets was evaluated using perfusion models. Our studies revealed a dose-dependent association of rFVIIa to the platelet cytoplasm with redistribution into the open canalicular system, and α granules. Mechanisms implicated in the internalization are multiple, involve GPIb and GPIV, and require phospholipids and cytoskeletal assembly. After platelet activation with thrombin, platelets exposed rFVIIa on their membrane. Perfusion studies revealed that the presence of 30% of platelets containing FVIIa improved platelet aggregate formation and enhanced fibrin generation (P < 0.01 versus control). Our results indicate that, at therapeutic concentrations, rFVIIa can be internalized into platelets, where it is protected from physiological clearance mechanisms and can still promote hemostatic activity. Redistribution of rFVIIa into platelets may explain the prolonged prophylactic effectiveness of rFVIIa in hemophilia.
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Affiliation(s)
- Irene Lopez-Vilchez
- Hemotherapy and Hemostasis Service, Hospital Clinic, Biomedical Diagnostics Center CDB, Institute of Biomedical Research August Pi i Sunyer (IDIBAPS), University of Barcelona, Barcelona, Spain
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22
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Clearance of rFVIIa and NN1731 after intravenous administration to Beagle dogs. Eur J Pharm Sci 2011; 42:578-83. [DOI: 10.1016/j.ejps.2011.02.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Revised: 01/20/2011] [Accepted: 02/24/2011] [Indexed: 11/20/2022]
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Brophy DF, Martin EJ, Christian Barrett J, Nolte ME, Kuhn JG, Gerk PM, Carr ME, Pelzer H, Agersø H, Ezban M, Hedner U. Monitoring rFVIIa 90 μg kg⁻¹ dosing in haemophiliacs: comparing laboratory response using various whole blood assays over 6 h. Haemophilia 2011; 17:e949-57. [PMID: 21362113 DOI: 10.1111/j.1365-2516.2011.02492.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Recombinant FVIIa is a haemostatic agent administered to patients with severe FVIII or FIX deficiency with inhibitors. Although rFVIIa is effective at stopping bleeding, a reliable assay to monitor its effect is lacking. To characterize the pharmacokinetics and global coagulation effects of rFVIIa for 6 h following a IV dose of 90 μg kg⁻¹. Ten non-bleeding subjects with severe FVIII or FIX deficiency were infused with a single-dose of rFVIIa 90 μg k⁻¹ body weight and blood was collected before and at 0.5, 1, 2, 4 and 6 h postdose. Global haemostasis was characterized throughout the study utilizing whole blood analyses (Hemodyne HAS, TEG, ROTEM). The clearance and half-life of factor FVII:C was estimated as 39.0 ± 8.8 mL h⁻¹ kg⁻¹ and 2.1 ± 0.2 h respectively. There was good inter-assay agreement with respect to clot initiation parameters (R, CT and FOT) and these parameters all fell to a mean of approximately 9 min following rFVIIa dosing. The platelet contractile force (PCF) and clot elastic modulus (CEM) were positively correlated to FVII:C (P < 0.0001), and these parameters were dynamic throughout the 6-h period. The MA and MCF did not correlate to FVII:C nor did they significantly change during the study. Prothrombin F1 + 2 significantly increased following rFVIIa dosing (P < 0.001), but remained steady throughout the study. There was no change in D-dimer concentrations over time. The FOT, R and CT characterized clot initiation following rFVIIa dosing. The PCF and CEM were correlated to FVII:C and characterized the dynamics of platelet function and clot strength over the rFVIIa dosing interval. The clinical significance of these findings needs additional study.
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Affiliation(s)
- D F Brophy
- Coagulation Advancement Laboratory, Department of Pharmacotherapy and Outcomes Science, Virginia Commonwealth University (VCU), Richmond, VA, USA.
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Recombinant factor VIIa reduces bleeding after blunt liver injury in coagulopathic, hypofibrinogenaemic pigs. Br J Anaesth 2010; 105:789-97. [DOI: 10.1093/bja/aeq263] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
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Regulation and Differential Role of the Tissue Factor Isoforms in Cardiovascular Biology. Trends Cardiovasc Med 2010; 20:199-203. [DOI: 10.1016/j.tcm.2011.08.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Accepted: 07/27/2011] [Indexed: 01/08/2023]
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Pendurthi UR, Rao LVM. Factor VIIa interaction with endothelial cells and endothelial cell protein C receptor. Thromb Res 2010; 125 Suppl 1:S19-22. [PMID: 20156643 PMCID: PMC2838982 DOI: 10.1016/j.thromres.2010.01.026] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Plasma coagulation factor VIIa (FVIIa) initiates the coagulation cascade by binding to its cofactor, tissue factor (TF) on cell surfaces, which eventually leads to fibrin deposition and platelet activation. Recent studies showed that FVIIa also binds to endothelial cell protein C receptor (EPCR), a known cellular receptor for anticoagulant protein C\activated protein C, on the endothelium. The present article reviews our current knowledge of FVIIa interaction with EPCR and discusses the potential significance of this interaction in hemostasis, treatment of bleeding disorders with pharmacological doses of FVIIa and FVIIa clearance.
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Affiliation(s)
- Usha R Pendurthi
- Center for Biomedical Research, The University of Texas Health Science Center at Tyler, TX 75708, USA.
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27
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Grottke O, Henzler D, Rossaint R. Activated recombinant factor VII (rFVIIa). Best Pract Res Clin Anaesthesiol 2010; 24:95-106. [DOI: 10.1016/j.bpa.2009.09.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Gopalakrishnan R, Hedner U, Ghosh S, Nayak RC, Allen TC, Pendurthi UR, Rao LVM. Bio-distribution of pharmacologically administered recombinant factor VIIa (rFVIIa). J Thromb Haemost 2010; 8:301-10. [PMID: 19943873 PMCID: PMC2849270 DOI: 10.1111/j.1538-7836.2009.03696.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Recent clinical studies suggest that the prophylactic use of recombinant factor VIIa (rFVIIa) markedly reduces the number of bleeding episodes in hemophilic patients with inhibitors. Given the short biological half-life of rFVIIa, it is unclear how rFVIIa could be effective in prophylactic treatment. OBJECTIVES To examine the extravascular distribution of pharmacologically administered rFVIIa to obtain clues on how rFVIIa could work in prophylaxis. METHODS Recombinant mouse FVIIa tagged with AF488 fluorophore (AF488-FVIIa) was administered into mice via the tail vein. At different time intervals following the administration, mice were exsanguinated and various tissues were collected. The tissue sections were processed for immunohistochemistry to evaluate distribution of rFVIIa. RESULTS rFVIIa, immediately following the administration, associated with the endothelium lining of large blood vessels. Within 1 h, rFVIIa bound to endothelial cells was transferred to the perivascular tissue surrounding the blood vessels and thereafter diffused throughout the tissue. In the liver, rFVIIa was localized to sinusoidal capillaries and accumulated in hepatocytes. In bone, rFVIIa was accumulated in the zone of calcified cartilage and some of it was retained there for a week. The common finding of the present study is that rFVIIa in extravascular spaces was mostly localized to regions that contain TF expressing cells. CONCLUSIONS The present study demonstrates that pharmacologically administered rFVIIa readily associates with the vascular endothelium and subsequently enters into extravascular spaces where it is likely to bind to TF and is retained for extended time periods. This may explain the prolonged pharmacological effect of rFVIIa.
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Affiliation(s)
- R Gopalakrishnan
- Center for Biomedical Research, The University of Texas Health Science Center, Tyler, TX 75703, USA
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Vitamin-K-abhängige Gerinnungsfaktoren. Hamostaseologie 2010. [DOI: 10.1007/978-3-642-01544-1_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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PEI XH, CHI S, WANG JT, LIN ZX, ZHANG XH, GENG JG. Generation and Application of Active Recombinant Mouse Tissue Factor and Its Function-blocking Monoclonal Antibody*. PROG BIOCHEM BIOPHYS 2009. [DOI: 10.3724/sp.j.1206.2008.00639] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Al-Ruzzeh S, Navia JL. The “Off-Label” Role of Recombinant Factor VIIa in Surgery: Is the Problem Deficient Evidence or Defective Concept? J Am Coll Surg 2009; 209:659-67. [DOI: 10.1016/j.jamcollsurg.2009.07.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2009] [Revised: 07/20/2009] [Accepted: 07/22/2009] [Indexed: 01/31/2023]
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Abstract
Bleeding is a common and potentially serious complication of acute and chronic renal failure. The pathogenesis of bleeding in uremia is multifactorial; however, the major role is played by abnormalities in platelet-platelet and platelet-vessel wall interaction. Platelet dysfunction is partially due to uremic toxins present in circulating blood. Despite decreased platelet function, abnormalities of blood coagulation and fibrinolysis predispose the uremic patients to a hypercoagulable state carrying the risk of cardiovascular and thrombotic complications. Dialysis improves platelet abnormalities and reduces, but does not eliminate, the risk of hemorrhage. Hemodialysis can even contribute to the bleeding through the continuous platelet activation induced by the interaction between blood and artificial surfaces and the use of anticoagulants. Correction of anemia improves hemostasis in uremic patients. Therapeutic management of bleeding in patients with uremia is discussed.
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Affiliation(s)
- Miriam Galbusera
- Mario Negri Institute for Pharmacological Research, Via Gavazzeni 11, Bergamo, Italy
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Efficacy and safety of activated recombinant factor VII in cardiac surgical patients. Curr Opin Anaesthesiol 2009; 22:95-9. [DOI: 10.1097/aco.0b013e32831a40a3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Abstract
Since the first description of the haemostatic process by Morawitz in 1904, knowledge about the haemostasis mechanism has undergone substantial modifications. Increasing knowledge of enzymology, purification and characterisation of coagulation proteins led to the introduction of the waterfall or cascade model of coagulation. However, these models were based on in vitro studies in the presence of artificial phospholipids and the absence of cells. Two pathways to achieve the formation of a haemostatic fibrin plug were identified, the so-called `extrinsic system' involving both factors present in the circulation and from the extravascular space, and the `intrinsic system' using only factors present in the circulation. However, with increasing knowledge about the interaction between factors from the two systems, the relevance of this model was questioned. The availability of recombinant FVIIa has made further research of the role of FVII/FVIIa and TF feasible, resulting in the current concept of haemostasis according to which the process principally occurs on two cell surfaces, the TF-bearing cell and the thrombin-activated platelet. A limited amount of thrombin is generated by the FVIIa-TF complex on the TF-bearing cell resulting in activation of platelets, FIX, FVIII and FV. The further and full thrombin generation then takes place on the activated platelet surface. The most frequently used assays for evaluation of the global haemostatic capacity are the prothrombin time (PT) and the activated partial thromboplastin time (APTT). The PT measures the formation of a fibrin clot in the presence of an abundance of TF thereby principally reflecting the initial thrombin generation dependent especially on FVII, FV and FX, while the APTT mimics the processes on the activated platelet surface involving FVIII, FIX, FXl, FV, FX and prothrombin. For more specific analyses, assay systems measuring the level of various coagulation factors are available. Platelet function is measured by platelet count and bleeding time. The platelet aggregation response to different agonists can be measured in special aggregometers. The usefulness of these techniques in evaluating a potential bleeding risk is, however, doubtful.
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Hardy JF, Bélisle S, Van der Linden P. Efficacy and Safety of Recombinant Activated Factor VII to Control Bleeding in Nonhemophiliac Patients: A Review of 17 Randomized Controlled Trials. Ann Thorac Surg 2008; 86:1038-48. [DOI: 10.1016/j.athoracsur.2008.05.013] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2008] [Revised: 05/05/2008] [Accepted: 05/06/2008] [Indexed: 11/27/2022]
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36
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Recombinant Activated Factor VII: The Delicate Balance between Efficacy and Safety. Intensive Care Med 2008. [DOI: 10.1007/978-0-387-77383-4_70] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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