Matafonov A.,Vanderbilt University |
Matafonov A.,Tomsk Polytechnic University |
Leung P.Y.,Oregon Health And Science University |
Leung P.Y.,Aronora Inc. |
And 15 more authors.
Blood | Year: 2014
The plasma zymogens factor XII (fXII) and factor XI (fXI) contribute to thrombosis in a variety of mouse models. These proteins serve a limited role in hemostasis, suggesting that antithrombotic therapies targeting them may be associated with low bleeding risks. Although there is substantial epidemiologic evidence supporting a role for fXI in human thrombosis, the situation is not as clear for fXII. We generated monoclonal antibodies (9A2and15H8) against the human fXII heavy chain that interfere with fXII conversion to the protease factor XIIa (fXIIa). The anti-fXII antibodies were tested in models in which anti-fXI antibodies are known to have antithrombotic effects. Both anti-fXII antibodies reduced fibrin formation in human blood perfused through collagen-coated tubes. fXII-deficient mice are resistant to ferric chloride-induced arterial thrombosis, and this resistance can be reversed by infusion of human fXII. 9A2 partially blocks, and 15H8 completely blocks, the prothrombotic effect of fXII in this model. 15H8 prolonged the activated partial thromboplastin time of baboon and human plasmas. 15H8 reduced fibrin formation in collagen-coated vascular grafts inserted into arteriovenous shunts in baboons, and reduced fibrin and platelet accumulation downstream of the graft. These findings support a role for fXII in thrombus formation in primates. © 2014 by The American Society of Hematology.
Verbout N.G.,University of Oregon |
Verbout N.G.,Aronora Inc. |
Yu X.,University of Oregon |
Healy L.D.,University of Oregon |
And 8 more authors.
Metabolic Brain Disease | Year: 2014
Multiple sclerosis (MS) is a neuroinflammatory disease characterized by demyelination and axonal damage of the central nervous system. The pathogenesis of MS has also been linked to vascular inflammation and local activation of the coagulation system, resulting in perivascular fibrin deposition. Treatment of experimental autoimmune encephalomyelitis (EAE), a model of human MS, with antithrombotic and antiinflammatory activated protein C (APC) reduces disease severity. Since recombinant APC (Drotecogin alfa), originally approved for the treatment of severe sepsis, is not available for human MS studies, we tested the hypothesis that pharmacologic activation of endogenous protein C could likewise improve the outcome of EAE. Mice were immunized with murine myelin oligodendrocyte glycoprotein (MOG) peptides and at the onset of EAE symptoms, were treated every other day with either WE thrombin (25 μg/kg; i.v.), a selective recombinant protein C activator thrombin analog, or saline control. Mice were monitored for changes in disease score until euthanized for ex vivo analysis of inflammation. Administration of WE thrombin significantly ameliorated clinical severity of EAE, reduced inflammatory cell infiltration and demyelination, suppressed the activation of macrophages comprising the CD11b + population and reduced accumulation of fibrin (ogen) in the spinal cord. These data suggest that symptomatic MS may respond to a treatment strategy that involves temporal pharmacological enhancement of endogenous APC generation. © 2014, Springer Science+Business Media New York.
Gailani D.,Vanderbilt University |
Gruber A.,Aronora Inc
Arteriosclerosis, Thrombosis, and Vascular Biology | Year: 2016
Factor XIa is a plasma serine protease that contributes to thrombin generation primarily through proteolytic activation of factor IX. Traditionally considered part of the intrinsic pathway of coagulation, several lines of evidence now suggest that factor XIa serves as an interface between the vitamin-K-dependent thrombin generation mechanism and the proinflammatory kallikrein-kinin system, allowing the 2 systems to influence each other. Work with animal models and results from epidemiological surveys of human populations support a role for factor XIa in thromboembolic disease. These data and the clinical observation that deficiency of factor XI, the zymogen of factor XIa, produces a relatively mild bleeding disorder suggest that drugs targeting factor XI or XIa could produce an antithrombotic effect while leaving hemostasis largely intact. Results of a recent trial comparing antisense-induced factor XI reduction to standard-dose low molecular-weight heparin as prophylaxis for venous thrombosis during knee replacement are encouraging in this regard. Here, we discuss recent findings on the biochemistry, physiology, and pathology of factor XI as they relate to thromboembolic disease. © 2016 American Heart Association, Inc.
Puy C.,Oregon Health And Science University |
Tucker E.I.,Oregon Health And Science University |
Tucker E.I.,Aronora Inc |
Wong Z.C.,Oregon Health And Science University |
And 7 more authors.
Journal of Thrombosis and Haemostasis | Year: 2013
Background: Inorganic polyphosphates (polyP), which are secreted by activated platelets (short-chain polyP) and accumulate in some bacteria (long-chain polyP), support the contact activation of factor XII (FXII) and accelerate the activation of FXI. Objectives: The aim of the present study was to evaluate the role of FXI in polyP-mediated coagulation activation and experimental thrombus formation. Methods and Results: Pretreatment of plasma with antibodies that selectively inhibit FXI activation by activated FXII (FXIIa) or FIX) activation by activated FXI (FXIa) were not able to inhibit the procoagulant effect of long or short-chain polyP in plasma. In contrast, the FXIIa inhibitor, corn trypsin inhibitor, blocked the procoagulant effect of long and short polyP in plasma. In a purified system, long polyP significantly enhanced the rate of FXII and prekallikrein activation and the activation of FXI by thrombin but not by FXIIa. In FXI-deficient plasma, long polyP promoted clotting of plasma in an FIX-dependent manner. In a purified system, the activation of FXII and prekallikrein by long polyP promoted FIX activation and prothombin activation. In an ex vivo model of occlusive thrombus formation, inhibition of FXIIa with corn trypsin inhibitor but not of FXI with a neutralizing antibodies abolished the prothrombotic effect of long polyP. Conclusions: We propose that long polyP promotes FXII-mediated blood coagulation bypassing FXI. Accordingly, some polyp-containing pathogens may have evolved strategies to exploit polyP-initiated FXII activation for virulence, and selective inhibition of FXII may improve the host response to pathogens. © 2013 International Society on Thrombosis and Haemostasis.
Crosby J.R.,Isis Pharmaceuticals |
Marzec U.,Oregon Health And Science University |
Revenko A.S.,Isis Pharmaceuticals |
Zhao C.,Isis Pharmaceuticals |
And 10 more authors.
Arteriosclerosis, Thrombosis, and Vascular Biology | Year: 2013
Objective-During coagulation, factor IX (FIX) is activated by 2 distinct mechanisms mediated by the active proteases of either FVIIa or FXIa. Both coagulation factors may contribute to thrombosis; FXI, however, plays only a limited role in the arrest of bleeding. Therefore, therapeutic targeting of FXI may produce an antithrombotic effect with relatively low hemostatic risk. Approach and Results-We have reported that reducing FXI levels with FXI antisense oligonucleotides produces antithrombotic activity in mice, and that administration of FXI antisense oligonucleotides to primates decreases circulating FXI levels and activity in a dose-dependent and time-dependent manner. Here, we evaluated the relationship between FXI plasma levels and thrombogenicity in an established baboon model of thrombosis and hemostasis. In previous studies with this model, antibody-induced inhibition of FXI produced potent antithrombotic effects. In the present article, antisense oligonucleotides-mediated reduction of FXI plasma levels by =50% resulted in a demonstrable and sustained antithrombotic effect without an increased risk of bleeding. Conclusions-These results indicate that reducing FXI levels using antisense oligonucleotides is a promising alternative to direct FXI inhibition, and that targeting FXI may be potentially safer than conventional antithrombotic therapies that can markedly impair primary hemostasis. © 2013 American Heart Association, Inc.
Agency: Department of Health and Human Services | Branch: National Institutes of Health | Program: SBIR | Phase: Phase II | Award Amount: 2.00M | Year: 2015
DESCRIPTION provided by applicant Sepsis a detrimental systemic inflammatory and procoagulant response to infections remains a leading cause of death despite antibiotics and significant advances in disease management Antithrombotic drugs e g heparins can limit septic disseminated intravascular coagulation DIC however they can produce severe bleeding side effects and may support pathogen virulence potentially counterbalancing their antithrombotic and antiinflammatory benefits There are no FDA approved antithrombotic treatments for severe sepsis associated DIC Consequently there is a critical treatment gap and an unmet medical need for a safe therapeutic to improve sepsis outcomes Our unique product candidate a monoclonal antibody humanized E xisomab G that inhibits coagulation factor XI FXI activation by activated factor XII FXIIa directly addresses this critical need Compelling data generated during our Phase I II Advanced Technology SBIR shows that FXI contributes to lethal septic DIC and consumptive coagulopathy and supports the hypothesis that inhibition of FXI activation may improve sepsis outcomes In humans FXI deficiency is accompanied by only a minor bleeding diathesis while FXII deficiency has no known adverse effects Therefore we propose that selectively targeting FXI activation by FXIIa using G represents a fundamentally new and safer systemic anticoagulation strategy that may be useful to prevent or treat the thrombotic complications of severe sepsis without increasing bleeding risks or interfering with extrinsic pathway dependent innate immunity We are on track to reach all of our Phase II milestones by the beginning of Phase IIB and have confirmed the efficacy and safety of E in polymicrobial peritoneal infection and in listeriosis in mice established synergy with antibiotics successfully humanized E xisomab G completed manufacturing cell line development and established a strategic partnership with Bayer AG We have developed IND enabling GLP toxicity protocols for studies will commence at Charles River Labs Reno NV upon release of our toxicology lot by Bayer Healthcare LLC Berkeley CA in Nov We are also on track for our pre IND meeting with FDA in Jan This Phase IIB Bridge Award combined with our secured matching funds will provide essential support for continued product development towards an IND application and clinical trials Our specific aims are to Manufacture a cGMP lot of G for GLP stability and human studies Prepare and file an IND application to test G in sepsis and Evaluate the safety tolerability pharmacokinetics and pharmacodynamics of G in a phase clinical trial Our critical milestone for Phase IIB is absence of dose limiting toxicity in the frst phase study of xisomab G PUBLIC HEALTH RELEVANCE Blood clots significantly contribute to the high death rate associated with sepsis a life threatening complication of infections However drugs that are effective against blood clots antithrombotic drugs or andquot blood thinnersandquot have limited overall effectiveness in sepsis primarily because they also aggravate the bleeding tendency that accompanies severe sepsis There is no FDA approved antithrombotic drug for sepsis representing a treatment gap and major unmet medical need that we now address with the development of a new antithrombotic drug that does not increase bleeding and thus provides a new approach for treating the blood clotting complications of sepsis
Agency: Department of Health and Human Services | Branch: National Institutes of Health | Program: SBIR | Phase: Phase I | Award Amount: 299.56K | Year: 2016
DESCRIPTION provided by applicant This Phase I II Fast Track application is being re submitted under the NHLBI Small Business Topics of Special Interest for Fiscal Year HLS Certain life saving interventions such as cardiopulmonary bypass CPB extracorporeal membrane oxygenation ECMO or ventricular assist device VAD pump require the use of high dose heparin to maintain blood flow through the devices and or to prevent downstream thromboembolic complications Several other invasive vascular procedures also utilize profound temporal anticoagulation such as during and after prosthetic vascular graft implantation Unfortunately antithrombotic agents such as heparin inadvertently target vital hemostatic molecular mechanisms and can produce severe dose limiting hemorrhagic toxicity Consequently the level of anticoagulation must be limited to balance the risk of bleeding with thrombosis As a result thrombotic complications can be frequent and devastating Our recent studies suggest that coagulation factor XII FXII contributes to the progression of thrombosis and thereby is a potential target for a new class of antithrombotic drugs Since data suggests that FXII does not contribute to hemostasis and FXII deficiency is an asymptomatic condition in mammals FXII inhibition is unlikely to have significant adverse effects We have generated a proprietary murine monoclonal antibody H against human FXII that was created by immunizing FXII knockout mice and verified its anticoagulant and antithrombotic effects in preliminary primate experiments This proposed Phase I II Fast Track project will initiate the commercial development of a recombinant humanized version of H rh H a product candidate that could be used as a stand alone or as an adjuvant anticoagulant to increase the antithrombotic efficacy of heparin without further increasing heparin associated bleeding risks The Specific Aims for this project that will be necessary to support H development towards an investigational new drug IND application are to Evaluate the antithrombotic effect of the murine anti FXII antibody H in a primate model of experimental extracorporeal membrane oxygenation ECMO Determine the activity and efficacy of recombinant humanized H rh H and Manufacture rh H for use in GLP toxicity studies The rh H approach represents a fundamentally new therapeutic anticoagulation concept since FXII inhibition is expected to reduce the formation of contact initiated blood clots in synthetic grafts and extracorporeal devices without a detrimental effect on residual bleeding control in critically ill anticoagulated patients Success of this project and reaching our critical milestones will lead directly to the next stage of product development that will consist of GLP toxicity and stability studies IND preparation and filing followed by the initiation of phase first in human safety studies of our innovative antithrombotic drug candidate PUBLIC HEALTH RELEVANCE The blood thinner heparin has long been used to prevent blood clot formation during certain life saving procedures such as extracorporeal membrane blood oxygenation in patients whose lungs fail or during open heart surgeries but heparin can have severe bleeding side effects and is often not fully effective Consequently there remains an urgent unmet medical need for improving the safety and effectiveness of anticoagulation during interventional vascular procedures The proposed research addresses this need by engaging in the development of a new anticoagulant antibody drug candidate rh H which does not affect hemostasis bleeding control but has antithrombotic effects and therefore could be used alone or to safely enhance the effectiveness of heparin
Aronora Inc. and Absci Llc | Date: 2014-02-05
The present invention provides methods of producing thrombin using coordinated coexpression systems, and particularly inducible coexpression systems, capable of controlled induction of expression of each gene product required for the production of thrombin, and the thrombin produced by this method.
Vanderbilt University, Aronora Inc. and University of Oregon | Date: 2013-12-06
Provided are antibodies that selectively bind to and inhibit activation of coagulation factor XII. Methods of treatment employing these antibodies are described herein.
Agency: Department of Health and Human Services | Branch: | Program: SBIR | Phase: Phase II | Award Amount: 2.66M | Year: 2014
DESCRIPTION (provided by applicant): Project Summary/Abstract Treatment of acute ischemic stroke (AIS) with the thrombolytic/antithrombotic agent tissue plasminogen activator (tPA, Activase(R)) is limited due to the potential for severe hemorrhagic side effects. The first symptoms of acute ischemia to tPA treatment ( time to needle ) can span hours, even in developed urban areas, since an established diagnosis in a hospital setting is required before thrombolytic therapy. Consequently, there is a major unmet medical need for safe antithrombotic agents with no risk of bleeding that can be administered immediately as an emergency measure upon signs of acute cardio- and cerebrovascular events. To directly address this need, our company has been developing a novel antithrombotic agent for the safe treatment of AIS. The product candidate is a bioengineered recombinant selective protein C activator enzyme (PCA) that has potent antithrombotic effects without increasing hemorrhagic risks. Our proprietary PCA mol