US20180292420A1 - Development of novel automated screening method for detection of fviii inhibitors - Google Patents

Development of novel automated screening method for detection of fviii inhibitors Download PDF

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US20180292420A1
US20180292420A1 US15/572,085 US201615572085A US2018292420A1 US 20180292420 A1 US20180292420 A1 US 20180292420A1 US 201615572085 A US201615572085 A US 201615572085A US 2018292420 A1 US2018292420 A1 US 2018292420A1
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patient
inhibitor
ratio
sample
factor viii
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Matthew Stephen Evans
Keri Jon Donaldson
Mary Elaine Dye
Michael H. Creer
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Prescient Medicine Holdings LLC
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
    • G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
    • G01N33/86—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing involving blood coagulating time or factors, or their receptors
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P37/00—Drugs for immunological or allergic disorders
    • A61P37/02—Immunomodulators
    • A61P37/04—Immunostimulants
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P7/00—Drugs for disorders of the blood or the extracellular fluid
    • A61P7/04—Antihaemorrhagics; Procoagulants; Haemostatic agents; Antifibrinolytic agents
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2333/00—Assays involving biological materials from specific organisms or of a specific nature
    • G01N2333/435—Assays involving biological materials from specific organisms or of a specific nature from animals; from humans
    • G01N2333/745—Assays involving non-enzymic blood coagulation factors
    • G01N2333/755—Factors VIII, e.g. factor VIII C [AHF], factor VIII Ag [VWF]
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2800/00—Detection or diagnosis of diseases
    • G01N2800/52—Predicting or monitoring the response to treatment, e.g. for selection of therapy based on assay results in personalised medicine; Prognosis

Definitions

  • the present disclosure relates generally to the field of blood coagulation and more particularly to identification of coagulation inhibitors in patient samples.
  • Factor VIII (FVIII) activity is determined by directly measuring the activated partial thromboplastin time (APTT) of a patient plasma sample and determining the percent activity from a standard curve generated from plotting the measured clotting time (in seconds) on a semi-log scale vs a known percent activity of the standard at several specific dilution points. Factor VIII activity for the patient samples is then performed on dilutions of patient plasma mixed with equal amounts of plasma deficient in the factor to be measured, and the percent of factor in the patient plasma is calculated from the standard curve by plotting the observed clotting time for a specific dilution of the patient sample.
  • APTT activated partial thromboplastin time
  • Disclosed herein are methods addressing the shortcomings of the art, and may provide any number of additional or alternative advantages, such as providing an objective and automated tool to assess parallelism as an added screening tool for the presence of a Factor VIII inhibitor.
  • Certain embodiments of the invention include a method for determining the presence of a Factor VIII inhibitor in a patient sample.
  • the method includes the steps of: generating a patient curve associated with a patient sample and having a patient slope (Ps); generating a standard curve associated with a control sample and having a control slope (Cs), and comparing the Ps and the Cs to obtain a Ps/Cs parallelism ratio, wherein a Ps/Cs parallelism ratio of less than 0.45 is indicative of presence of a Factor VIII inhibitor in the patient sample.
  • the method further includes the Ps and Cs curves being generated by plotting a plurality of clotting time points for a series of dilutions of the patient sample and the control sample relative to the FVIII clotting activity.
  • the Ps/Cs parallelism ratio is determined by a microprocessor in electronic communication with a clotting detection machine.
  • the method further includes determining the ratio of less than 0.45 and administering to the patient at least one agent for treatment of a condition associated with the presence of the Factor VIII inhibitor.
  • the condition is hemophilia A.
  • the condition is an autoimmune disorder.
  • the agent is one or more of the following: human factor VIII, porcine factor VIII, and an FVIII bypassing agent.
  • the method further includes producing an output by the microprocessor, the output being capable of perceived visually or audibly by a human user or as digital information readable by a computer, wherein the output comprises an indication of the Ps/Cs ratio.
  • Certain embodiments of the invention include a method of determining the presence of a coagulation inhibitor in a bodily fluid of a patient.
  • the method includes the steps of detecting whether a coagulation inhibitor is present in the patient sample by generating a patient curve associated with the patient sample and having a patient slope (Ps) and generating a standard curve associated with a control sample and having a control slope (Cs).
  • Ps patient curve associated with the patient sample and having a patient slope
  • Cs control slope
  • the Ps and Cs curves are generated by plotting a plurality of clotting time points for a series of dilutions of the patient sample and the control sample relative to the clotting activity.
  • the method includes the steps of comparing the Ps and the Cs to obtain a Ps/Cs parallelism ratio, wherein a Ps/Cs parallelism ratio of less than a predetermined ratio is indicative of presence of a coagulation inhibitor in the patient sample.
  • the predetermined ratio is about 0.45.
  • the coagulation inhibitor is dabigatran.
  • the coagulation inhibitor is Factor VIII inhibitor.
  • the coagulating agent is mammalian Factor VIII.
  • Certain embodiments of the invention include a method of determining the presence of an anti-coagulating compound in a bodily fluid of a patient and treating such patient.
  • the method includes the steps of obtaining a patient sample of the bodily fluid; detecting whether an anti-coagulating compound is present in the patient sample; and administering an effective amount of coagulating agent to the patient, in response to a Ps/Cs parallelism ratio being less than a predetermined ratio.
  • the Ps/Cs parallelism ratio is determined by generating a patient curve associated with the patient sample and having a patient slope (Ps); generating a standard curve associated with a control sample and having a control slope (Cs), and the Ps and Cs curves being generated by plotting a plurality of clotting time points for a series of dilutions of the patient sample and the control sample relative to the clotting activity; and comparing the Ps and the Cs to obtain a Ps/Cs parallelism ratio.
  • the predetermined ratio is about 0.45.
  • the anti-coagulating compound is Factor VIII inhibitor.
  • the coagulating agent is mammalian Factor VIII.
  • the anti-coagulating compound is dabigatran.
  • the anti-coagulating compound is rivaroxaban.
  • FIG. 1 is an example of parallelism curve with parallel curves obtained from analysis of biological samples obtained from a patient without inhibitor.
  • FIG. 2 is an example of parallelism curve with non-parallel curves obtained from analysis of biological samples obtained from a patient with inhibitor.
  • FIG. 3 is an example of a bell curve generated according to an embodiment.
  • a sample refers to bodily fluids from a patient or a healthy individual or a fluid specimen that serves as a control for the methods disclosed herein.
  • Non-limiting examples of a sample include blood, plasma, serum, blood extracts, or other blood products.
  • a predetermined ratio refers to a parallelism ratio standardized for a particular embodiment of the invention, and is determined, in many instances, by standardizing the reagents, reaction conditions, and instrumentation to evaluate samples.
  • the disclosure herein relates to improved, automated methods for identification of coagulation inhibitors in patient samples, and in particular for Factor VIII (FVIII) inhibitors.
  • the disclosure accordingly provides methods and systems for use in determining whether a patient sample contains a FVIII inhibitor, and can accordingly be used for diagnosis, or to aid in the diagnosis of a disease or other condition in an individual that is associated with FVIII inhibition.
  • Factor VIII is a well-known clotting factor with a very low normal plasma concentration of approximately 0.0007 ⁇ mol/L. It circulates as inactive plasma protein in a number of distinct fragmented species in a tightly associated complex with von Willebrand factor. Factor VIII activation occurs in the blood typically in response to an injury to a blood vessel. Activation comprises cleavage of FVIII between its A1 and A2 domains, resulting in an unstable heterotrimeric Factor VIIIa molecule. Factor VIIIa interacts with Factor IX with a subsequent, well characterized series of reactions that result in blood clot formation.
  • a FVIII inhibitor as the term is used herein can refer to a congenital deficiency of FVIII, or an acquired FVIII deficiency.
  • Such inhibitors include but are not necessarily limited to antibodies that bind with specificity to at least one epitope present on FVIII and/or FVIIa.
  • the inhibitor comprises alloantibodies to FVIII, such as in the case of an individual that has developed an antibody response to FVIII as a result of receiving blood or another FVIII-containing composition from a different individual, which occurs in, for example, some congenital hemophilia A patients.
  • the inhibitor can comprise an autoantibody to FVIII, such as in the case of an individual with, or at risk for developing acquired hemophilia. Such an individual may develop the autoantibodies and the hemophilia condition after birth, and often much later in life.
  • the present disclosure is suitable for determining FVIII inhibitors in individuals who have alloantibodies that inactivate FVIII, which typically occurs in direct proportion to their concentration (first-order kinetics), or acquired inhibitors/autoantibodies which typically show a non-linear inactivation pattern (type II or second-order kinetics). Additional applications of this technology could allow identification and classification of lupus anticoagulants, and allow rapid classification of the specific anticoagulant in the sample. Prior to the present disclosure this testing typically takes days to weeks and requires additional sub-specialty testing and expertise.
  • Stocks of buffered normal pooled plasma for use in making a 1:1 mix with patient plasma are commercially available.
  • the mixtures are typically incubated a 37° C. for at about 120 minutes during which the inhibitor, if present in the patient sample, neutralizes FVIII. Results from the patient sample and positive sample are compared.
  • a modified version of the Bethesda method i.e. the so-called “Nijmegen” modification, provides increased specificity for low-titer FVIII inhibitor measurements by buffering the pH of the patient and control mixtures with imidazole, and using FVIII-deficient plasma in the control mixture and patient dilutions.
  • a Bethesda unit is defined as the amount of antibody or other inhibitor that neutralizes in a plasma sample 50% of 1 unit of factor VIII:C in normal plasma after a 120 minute incubation at 37° C.
  • BU is calculated using doubling dilutions of patient plasma, ranging from 1:2-1:1024, in an imidazole containing buffer, and are incubated with an equal volume of NPP.
  • NPP will comprise approximately 100 IU/dl (1 IU/ml or 100%) of factor VIII.
  • a control that contains an equal volume of normal plasma mixed with buffer is used to establish the 100% value, or as discussed above for the Nijmegen modification, immunodepleted factor VIII deficient plasma is used to establish the 100% value.
  • residual factor VIII activity is determined. This is typically is performed using a standard single stage Activated Partial Thromboplastin Time (APTT) assay with the control as the 100% standard.
  • APTT is also known in the art as the Kaolin Cephalin Clotting Time (KCCT) and the Partial Thromboplastin Time with Kaolin (PTTK). These assays are well known in the art.
  • APTT is performed by addition of phospholipid (cephalin) and a contact activator (e.g.
  • Kaolin micronized silica or ellagic acid
  • APTT is the time taken from the addition of calcium to the formation of a fibrin clot.
  • Most laboratories employ an automated method for determining APTT, wherein clot formation is deemed to have occurred when the optical density of the mixture has exceeded a certain threshold.
  • the inhibitor concentration is then calculated from a graph constructed to show residual factor VIII activity versus inhibitor units.
  • Factor VIII activity is determined by directly measuring the activated partial thromboplastin time of a patient plasma sample and determining the percent activity from a standard curve generated from plotting the measured clotting time (in seconds) on a semi-log scale vs a known percent activity of the standard at several specific dilution points. This accordingly provides a line with a particular slope.
  • a control line (Cs) is compared to a patient line (Ps) to determine parallelism between the two lines.
  • Cs control line
  • Ps patient line
  • a ratio of the Ps/Cs curves of ⁇ 0.45 is indicative that the individual from whom the sample was obtained is in need of treatment for a condition associated with the presence of the FVIII inhibitor.
  • further characterization of the type of inhibitor can be performed.
  • further testing is performed to determine heparin contamination and/or the presence of lupus anticoagulant. Additional inhibitor identification classification, and anticoagulant drug classification will occur in the same process, with the ratio of the slopes being used to categorize both the presence and absence of the drug and type of agent present.
  • Certain embodiments of the invention can be used to distinguish between nonspecific clotting inhibitors such as lupus anticoagulants or specific clotting factor inhibitors, such as specific oral anticoagulants.
  • the disclosure includes determining a ratio of Ps/Cs curves of ⁇ 0.45 for an individual, and administering to the individual at least one agent for therapy of a disorder or condition associated with the present of the inhibitor in the individual. In embodiments, determining a ratio of Ps/Cs curves of ⁇ 0.45 is used to diagnose, or aid in a physician's diagnosis of a disorder.
  • the disorder comprises a congenital disorder, such as congenital Hemophilia A, or development of acquired factor VIII inhibitors, such as acquired Hemophilia A,
  • the disclosure comprises determining a ratio of Ps/Cs curves of ⁇ 0.45, diagnosing the patient with a disorder associated with the presence of at least one factor VIII inhibitor, and administering to the individual at least one exogenous agent for treating the disorder.
  • the individual is diagnosed with Hemophilia A, and is administered an agent for treating Hemophilia A.
  • testing a sample from an individual according to this disclosure and determining a ratio of Ps/Cs curves of ⁇ 0.45, and diagnosing the patient with a disorder associated with the presence of at least one factor VIII inhibitor is followed by administering to the individual at least one exogenous agent for treating the disorder.
  • the agent is selected from 1-deamino-8-d-arginine vasopressin, an infusion of human or porcine factor VIII, an FVIII bypassing agent, such as an activated prothrombin complex concentrate, Xa or VIIa, including recombinant versions thereof, of the individual is administered an agent (or subjected to a process) for use in inhibitor elimination, or an agent used for immunosuppression.
  • an extracorporeal approach is used to, for example, remove autoantibodies to FVIII, such as with a plasmapheresis or immunoadsorption approach.
  • inhibitor reduction or elimination is used for bleeding patients, or patients who are scheduled for a surgical intervention, and who have high titer inhibitors and/or have failed to respond to bypassing agents.
  • the individuals are given FVIII replacement, such as an amount of FVIII effective to achieve hemostasis.
  • testing a sample from an individual according to this disclosure and determining a ratio of Ps/Cs curves of ⁇ 0.45, and diagnosing the patient with a disorder associated with the presence of at least one factor VIII inhibitor is followed by administering to the individual at least one immunosuppression agent, such as prednisolone.
  • the immunosuppression agent can be combined with another agent intended to enhance its effect, such as cyclophosphamide, azathioprine, vincristine, mycophenolate mofetil, 2-chlorodeoxyadenosine, Cyclosporine A, and combinations thereof.
  • testing a sample from an individual according to this disclosure and determining a ratio of Ps/Cs curves of ⁇ 0.45, and diagnosing the patient with a disorder associated with the presence of at least one factor VIII inhibitor is followed by administering to the individual intravenous immunoglobulin (IVIG).
  • IVIG intravenous immunoglobulin
  • the individual can also be treated with a targeted biologic therapy, such as rituximab, alone or in combination with other agents, such as prednisone and/or cyclophosphamide.
  • the method of this disclosure may be performed on an assay system or blood analyzer.
  • a device may perform an assay or other measurements, send information to a data processing apparatus, analyze the information, and display, print, or otherwise send results or other information determined during the analysis.
  • machines on which the method may be performed include, as non-limiting examples, the STA-R Evolution (manufactured by Diagnostica Stago) or blood coagulation analyzers such as the CA-1500. CA-660, CS-2011i, or CS-5100 (manufactured by Sysmex UK LTD).
  • Exemplary systems are described in U.S. Pat. Nos. 7,720,880, 7,085.669, the disclosures of each of which are all incorporated herein by reference.
  • the method of the disclosure is carried out using a machine in electronic communication with a microprocessor programmed to generate a ratio of Ps/Cs curves, and to identify samples that segregate on either side of the 0.45 threshold described herein.
  • the disclosure comprises receiving an input of digitized data corresponding BUs for at least one patient sample and at least one control sample; plotting the digitized data to obtain a Ps and Cs curve; calculating a Ps/Cs ratio from the digitized data, and providing an indication of the Ps/Cs ratio as a user-recognizable output.
  • the user-recognizable output is provided by a device selected from the group consisting of a visual display, a printer, an output data port, an RF transmitter, and digital medium storage device.
  • the disclosure comprises fixing in a tangible medium the ratio of Ps/Cs curves.
  • the tangible medium can be any type of tangible medium, such as any type of digital medium, including but not limited to a DVD, a CD-ROM, a portable flash memory device, or a printed or digitized report, etc., such as a spreadsheet or word processing document.
  • the disclosure includes providing the tangible medium to a health care provider to assist with development of a diagnosis and/or recommendation for treatment of the individual and/or for developing a prognosis for the individual, such as for treating hemophilia or any other disorder associated with the presence of FVIII inhibitor(s).
  • the disclosure includes sequential testing of samples from an individual over a period of time, such as a treatment period to monitor the progress of a therapeutic approach intended for treating hemophilia or any other disorder associated with the presence of FVIII inhibitor(s), and/or to determine whether the amount of inhibitors is the individual is being reduced and/or neutralized during the course of any particular therapy.
  • the logistical implications are highlighted by the fact that the assays described herein leverage routine factor clotting assays to provide an objective screening method for the presence of an inhibitor, which can easily be applied to any coagulation system platform.
  • Embodiments of the invention can also screen for the detection of inhibitors to other specific clotting factors or lupus anticoagulants.
  • Embodiments of the invention can also screen for the presence of an inhibitor effect in patients, who present with bleeding or recurrent venous thromboembolism while on the newer oral anticoagulants which directly inhibit Factor Xa and thrombin.
  • Certain embodiments of the method include determining the presence of an anti-coagulating compound in a bodily fluid of a patient and treating such patient.
  • the method includes the steps of obtaining a patient sample of the bodily fluid and detecting whether an anti-coagulating compound is present in the patient sample.
  • the presence of the anti-coagulating compound is detected by generating a patient curve associated with the patient sample and having a patient slope (Ps); generating a standard curve associated with a control sample and having a control slope (Cs), and comparing the Ps and the Cs to obtain a Ps/Cs parallelism ratio.
  • Ps patient slope
  • Cs control slope
  • the Ps and Cs curves are generated by plotting a plurality of clotting time points for a series of dilutions of the patient sample and the control sample relative to the FVIII clotting activity.
  • the Ps/Cs parallelism ratio being less than a predetermined ratio is indicative of the presence of an anti-coagulating compound in the patient.
  • An effective amount of coagulating agent is then administering to the patient.
  • Embodiments of the methods could also be used to screen patients on the new target specific oral anticoagulants.
  • venous thromboembolism in the United States is highlighted by the fact that there are 300,000 to 600,000 new cases each year with up to a 12% death rate within one month in those diagnosed with a pulmonary embolism.
  • thrombin time has been shown to be prolonged in a dose dependent manner, but is excessively sensitive.
  • An embodiment of the invention can include an automated screening assay to rapidly screen for the presence of any of these anticoagulants in a patient sample. For example, if dabigatran is identified and a reversal of bleeding is needed, one can use a specific coagulating agent such as idarucizumab. Depending on the needs of the patient and the specific treatment protocols, one can also use activated Prothrombin Complex Concentrate (FEIBA).
  • FEIBA activated Prothrombin Complex Concentrate
  • Certain situations may involve treatment protocols such as hemodialysis, with or without anti-fibrinolytic agents.
  • treatment protocols such as hemodialysis, with or without anti-fibrinolytic agents.
  • rivaroxaban, apixaban or edoxaban factor Xa inhibitors
  • edoxaban factor Xa inhibitors
  • Kcentra nonactivated Prothrombin Complex Concentrate
  • one may also use antifibrinolytics or targeted anticoagulants such as Andexanet.
  • Detection and measurement of platelet function is important for identifying patients with platelet dysfunction or hyperfunction, and also monitoring antiplatelet therapies.
  • Embodiments of the invention can also be deployed in evaluating platelet function and presence of anti-platelet agents.
  • Certain embodiments of the method include determining the presence of an antiplatelet agents in a bodily fluid of a patient. The method includes the steps of obtaining a patient sample of the bodily fluid and detecting whether an antiplatelet agent is present in the patient sample.
  • the presence of the antiplatelet agent is detected by generating a patient curve associated with the patient sample and having a patient slope (Ps); generating a standard curve associated with a control sample and having a control slope (Cs), and comparing the Ps and the Cs to obtain a Ps/Cs parallelism ratio.
  • the Ps and Cs curves are generated by conducting platelet function tests.
  • Platelet function tests may include one or more of Platelet Aggregation Studies (PFT) or Platelet Function Assay (PFA). Examples of platelet function tests include, without limitation, one or more of the following: closure time assay, viscoelastometry, bleeding time, platelet aggregation studies, or flow cytometry.
  • the class of antiplatelet drugs include irreversible cyclooxygenase inhibitors, adenosine diphosphate (ADP) receptor inhibitors, phosphodiesterase inhibitors, protease-activated receptor-1 (PAR-1) antagonists, glycoprotein IIB/IIIA inhibitors, adenosine reuptake inhibitors, and thromboxane inhibitors.
  • irreversible cyclooxygenase inhibitors include aspirin and Triflusal (Disgren).
  • adenosine diphosphate (ADP) receptor inhibitors include Clopidogrel (Plavix), Prasugrel (Effient), Ticagrelor (Brilinta), and Ticlopidine (Ticlid).
  • Phosphodiesterase inhibitors include Cilostazol (Pletal).
  • protease-activated receptor-1 (PAR-1) antagonists include Vorapaxar (Zontivity).
  • Examples of glycoprotein IIB/IIIA inhibitors include Abciximab (ReoPro), Eptifibatide (Integrilin), and Tirofiban (Aggrastat).
  • Examples of adenosine reuptake inhibitors include Dipyridamole (Persantine).
  • thromboxane inhibitors include thromboxane synthase inhibitors and thromboxane receptor antagonists (Terutroban).
  • Factor VIII assays determine Factor VIII activity (in percentage) from a standard curve. This standard curve is generated from plotting measured clotting time (in seconds) versus a known percent activity for the standard at several dilution points. Factor VIII activity for patient samples are then performed on dilutions of patient plasma mixed with equal amounts of known factor deficient plasma, and the percent of factor in the patient plasma is calculated from this standard curve by plotting the observed clotting time for a specific dilution of the patient sample.
  • the line given by the clotting times of the dilutions of the patient plasma should parallel that given by the dilutions of the system control plasma when plotted on a logarithmic scale.
  • the disclosures herein provide a validated screening tool for detecting the presence of an inhibitor to Factor VIII during routine FVIII assays.
  • This method has is adaptable for screening for the detection of inhibitors to other specific clotting factors such as FIX, lupus anticoagulants, and the presence of the newer oral anticoagulants which directly inhibit Factor Xa or thrombin.

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WO2016179547A1 (en) 2016-11-10
EP3292407A4 (en) 2019-01-02
JP6625730B2 (ja) 2019-12-25
US20210140985A1 (en) 2021-05-13

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