Patent Application
20160114010
All patents, patent applications and publications, and non-patent publications cited herein are hereby incorporated by reference in their entirety. The disclosures of these publications in their entireties are hereby incorporated by reference into this application in order to more fully describe the state of the art as known to those skilled therein as of the date of the invention described and claimed herein.
This patent disclosure contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure as it appears in the U.S. Patent and Trademark Office patent file or records, but otherwise reserves any and all copyright rights.
This application claims priority to U.S. Provisional Patent Application No. 61/799,875, filed Mar. 15, 2013, the disclosure of which is incorporated by reference.
The body can engage in blood clotting through the “extrinsic pathway” and the “intrinsic pathway.” Clotting factors mediate the clotting response in both pathways. Both pathways are activated by different stimuli and ultimately feed into a common machinery. In the extrinsic pathway, when vascular injury occurs, a subendothelial cell-surface glycoprotein called “Tissue Factor” (TF) (also known as Factor III) is released at the site of injury triggering blood coagulation in healthy individuals. Tissue factor is found on the outside of blood vessels—normally not exposed to the bloodstream.
Coagulation is mainly triggered by FVIIa activating FX after exposure of TF at the broken vessel wall. Approximately one percent of FVII is circulating in its activated enzyme form (FVIIa). FVIIa forms the so-called “extrinsic tenase” complex with TF leading to activation of factor X (FX) to FXa, which leads to activation of initial levels of thrombin, and to activation of FIX to FIXa. Thrombin is required to activate FVIII, FV, and platelets. Formation of the “intrinsic tenase” complex consisting of FIXa and FVIIIa leads to activation of FX at a rate which is several orders of magnitude higher than by the FVIIa/TF complex. These amounts of FXa are required to cause the “thrombin burst” leading to formation of enough fibrin to form a stable blood clot. All these processes occur on the membrane surfaces of activated platelets.
Platelets are anucleic cells that circulate in the blood of mammals. In the absence of trauma, the inner surface of blood vessels is lined with a thin layer of endothelial cells that acts to inhibit platelet activation. When blood vessels are damaged, fibrils of collagen in the extracellular matrix (ECM) are exposed. Platelets then begin to adhere to the collagen through the action of specific receptors for collagen present on their plasma membrane. These adhesions activate the platelets in addition to the earlier described mechanisms. Platelets are also activated by thrombin after initiation of coagulation.
Hemophilia refers to a group of bleeding disorders in which it takes a long time for the blood to clot. Hemophilia A is the most common form of the disorder and is caused by a deficiency in Factor VIII. Hemophilia B is less frequent and is caused by a deficiency in Factor IX. Both forms of hemophilia can be effectively treated by administration of either recombinant or plasma derived FVIII or FIX concentrates. Treatment of hemophilia is complicated by the development of inhibitory antibodies to factors VIII or IX. In the case of Factor VIII (FVIII), inhibitors develop in ˜30% of the patients. Currently approved therapies in these cases include the infusion of plasma-derived prothrombin complex concentrates, like FEIBA, or recombinant Factor VIIa (rFVIIa), as the therapies for acute bleeds.
The present invention relates to a platelet subpopulation with high binding capacity to recombinant activated factor VII (rFVIIa), and its use for the treatment of bleeding disorders. The present invention also relates to methods for determining whether a subject is a candidate for treatment with rFVIIa or alternative therapies.
In one aspect, the present invention provides a method of treating hemophilia in a subject in need thereof, the method comprising administering a therapeutically effective amount of rFVIIa to the subject, wherein (a) a sample of platelets derived from the subject was obtained; (b) a platelet population from the sample was incubated with rFVIIa; and (c) a subpopulation of platelets having at least a 4-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of the other platelets in the platelet population, was detected in the platelet population.
In another aspect, the present invention provides a method of treating hemophilia in a subject in need thereof, the method comprising administering a therapeutically effective amount of an alternative therapy to the subject, wherein (a) a sample of platelets derived from the subject was obtained; (b) a platelet population from the sample was incubated with rFVIIa; and (c) a subpopulation of platelets having at least a 4-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of the other platelets in the platelet population, was not detected in the platelet population.
In another aspect, the present invention provides a method of treating a non-hemophilia bleeding disorder in a subject in need thereof, the method comprising administering a therapeutically effective amount of rFVIIa to the subject, wherein (a) a sample of platelets derived from the subject was obtained; (b) a platelet population from the sample was incubated with rFVIIa; (c) a subpopulation of platelets having at least a 4-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of the other platelets in the platelet population, was detected in the platelet population; and (d) the subject does not have an unacceptable risk of thrombosis.
In another aspect, the present invention provides a method of treating a non-hemophilia bleeding disorder in a subject in need thereof, the method comprising administering a therapeutically effective amount of an alternative therapy to the subject, wherein (a) a sample of platelets derived from the subject was obtained; (b) a platelet population from the sample was incubated with rFVIIa; and (c) a subpopulation of platelets having at least a 4-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of the other platelets in the platelet population, was not detected in the platelet population.
In yet another aspect, the invention provides a method of treating a bleeding disorder in a subject in need thereof, the method comprising administering to the subject a therapeutically effective amount of a platelet population enriched with a subpopulation of platelets having at least a 4-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of the other platelets in the platelet population.
In one aspect, the present invention provides a method of treating a bleeding disorder in a subject in need thereof, the method comprising administering a therapeutically effective amount of rFVIIa to the subject, wherein (a) a sample of platelets derived from the subject was obtained; (b) a platelet population from the sample was incubated with rFVIIa; and (c) a subpopulation of platelets having at least a 4-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of the other platelets in the platelet population, was detected in the platelet population.
In yet another aspect, the present invention provides a method of treating a bleeding disorder in a subject in need thereof, the method comprising administering a therapeutically effective amount of an alternative therapy to the subject, wherein (a) a sample of platelets derived from the subject was obtained; (b) a platelet population from the sample was incubated with rFVIIa; and (c) a subpopulation of platelets having at least a 4-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of the other platelets in the platelet population, was not detected in the platelet population.
In one embodiment, the detection is by flow cytometry. In one embodiment, the platelets in the subpopulation of platelets are activated. In another embodiment, the platelets in the subpopulation of platelets are non-activated. In one embodiment, the platelets in the subpopulation of platelets are coated.
In one embodiment, the platelet population contains a subpopulation of platelets having about a 6-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of the other platelets in the platelet population. In another embodiment, the platelet population contains a subpopulation of platelets having about a 20-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of the other platelets in the platelet population. In another embodiment, the platelet population contains a subpopulation of platelets having about a 30-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of the other platelets in the platelet population. In one embodiment, the platelet population contains a subpopulation of platelets having about a 40-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of the other platelets in the platelet population.
In one embodiment, the sample of platelets is obtained from a blood sample or a serum sample from the subject. In one embodiment, the sample of platelets is a fresh sample, a concentrate, a preserved sample, a rehydrated lyophilized sample, or a frozen sample.
In one embodiment, the bleeding disorder is hemophilia. In one embodiment, the hemophilia is hemophilia A. In another embodiment, the hemophilia is hemophilia B. In one embodiment, the hemophilia A is congenital hemophilia A with inhibitors or acquired hemophilia A with inhibitory auto antibodies to FVIII, and the hemophilia B is congenital hemophilia B with inhibitors or acquired hemophilia B with inhibitory auto antibodies to FIX.
In one embodiment, the subject does not have an unacceptable risk of thrombosis. In another embodiment, the subject has an unacceptable risk of thrombosis.
In one embodiment, the alternative therapy is Prothrombin Complex Concentrate or activated Prothrombin Complex Concentrate. In one embodiment, the activated Prothrombin Complex Concentrate is FEIBA.
In one embodiment, the alternative therapy is BeneFix®, Kogenate® FS, Recombinate, Advate®, Helixate® FS, Koāte®-DVI, Stimate®, DDAVP®, Bebulin, Hemofil M®, cryoprecipitated antihaemophilic factor (AHF), or fresh frozen plasma (FFP).
In another embodiment, the alternative therapy is recombinant porcine FVIII, recombinant FV variants, recombinant FVIIa variants, recombinant FXa variants, FXIII, prothrombin, fibrinogen, a mix of coagulation factors, antibodies mimicking FVIII, peptides mimicking FVIII, compounds mimicking FVIII, peptide inhibitors of TFPI, antibody inhibitors of TFPI, compounds inhibiting TFPI or compounds inhibiting anti-coagulant proteins.
In one embodiment, the bleeding disorder is a non-hemophilia bleeding disorder. In one embodiment, the non-hemophilia bleeding disorder is blood loss from trauma, FVII deficiency, FV deficiency, FX deficiency, FXI deficiency, FXIII deficiency, fibrinogen deficiency, prothrombin deficiency, dilutional coagulopathy, thrombocytopenia, blood loss from high-risk surgeries, intracerebral hemorrhage, von Willebrand disease or von Willebrand disease with inhibitors to von Willebrand factor.
In one embodiment, the bleeding disorder is hemophilia, blood loss from trauma, FVII deficiency, FV deficiency, FX deficiency, FXI deficiency, FXIII deficiency, fibrinogen deficiency, prothrombin deficiency, dilutional coagulopathy, thrombocytopenia, blood loss from high-risk surgeries, intracerebral hemorrhage, von Willebrand disease or von Willebrand disease with inhibitors to von Willebrand factor.
In another aspect, the present invention provides a subpopulation of platelets isolated from a platelet population, wherein the platelets in the subpopulation of platelets have at least a 4-fold higher binding capacity to rFVIIa as compared to the binding capacity to rFVIIa of the other platelets in the platelet population.
In one embodiment, the higher binding capacity to rFVIIa is determined by flow cytometry. In one embodiment, the platelets in the subpopulation of platelets are activated. In another embodiment, the platelets in the subpopulation of platelets are non-activated. In another embodiment, the platelets in the subpopulation of platelets are coated.
In one embodiment, the platelets in the subpopulation of platelets have about a 6-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of the other platelets in the platelet population. In another embodiment, the platelets in the subpopulation of platelets have about a 20-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of the other platelets in the platelet population. In one embodiment, the platelets in the subpopulation of platelets have about a 30-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of the other platelets in the platelet population. In another embodiment, the platelets in the subpopulation of platelets have about a 40-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of the other platelets in the platelet population.
In one embodiment, the subpopulation of platelets is supplied in the form of a pharmaceutical composition. In one embodiment, the pharmaceutical composition is administered systemically to a subject in need thereof.
In one embodiment, the pharmaceutical composition is used to treat a bleeding disorder. In one embodiment, the bleeding disorder is hemophilia, blood loss from trauma, FVII deficiency, FV deficiency, FX deficiency, FXI deficiency, FXIII deficiency, fibrinogen deficiency, prothrombin deficiency, dilutional coagulopathy, thrombocytopenia, blood loss from high-risk surgeries, intracerebral hemorrhage, von Willebrand disease, or von Willebrand disease with inhibitors to von Willebrand factor.
In another aspect, the present invention provides a method of determining whether a subject is a candidate for treatment with rFVIIa, the method comprising (a) obtaining a sample of platelets derived from the subject; (b) incubating a platelet population from the sample with rFVIIa; (c) detecting whether the platelet population contains a subpopulation of platelets having at least a 4-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of the other platelets in the platelet population, wherein a subject is a candidate for treatment with rFVIIa if the subject does not have an unacceptable risk of thrombosis, and if the platelet population contains a subpopulation of platelets having at least a 4-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of the other platelets in the platelet population.
In one embodiment, the detection is by flow cytometry. In one embodiment, the platelets in the subpopulation of platelets are activated. In another embodiment, the platelets in the subpopulation of platelets are non-activated. In one embodiment, the platelets in the subpopulation of platelets are coated.
In one embodiment, the platelet population contains a subpopulation of platelets having about a 6-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of the other platelets in the platelet population. In another embodiment, the platelet population contains a subpopulation of platelets having about a 20-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of the other platelets in the platelet population. In another embodiment, the platelet population contains a subpopulation of platelets having about a 30-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of the other platelets in the platelet population. In one embodiment, the platelet population contains a subpopulation of platelets having about a 40-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of the other platelets in the platelet population.
In one embodiment, the sample of platelets is obtained from a blood sample or a serum sample from the subject. In another embodiment, the sample of platelets is a fresh sample, a concentrate, a preserved sample, a rehydrated lyophilized sample, or a frozen sample.
In one embodiment, the subject has a bleeding disorder. In one embodiment, the bleeding disorder is hemophilia, blood loss from trauma, FVII deficiency, FV deficiency, FX deficiency, FXI deficiency, FXIII deficiency, fibrinogen deficiency, prothrombin deficiency, dilutional coagulopathy, thrombocytopenia, blood loss from high-risk surgeries, intracerebral hemorrhage, von Willebrand disease or von Willebrand disease with inhibitors to von Willebrand factor. In another embodiment, the bleeding disorder is blood loss from trauma, FVII deficiency, FV deficiency, FX deficiency, FXI deficiency, FXIII deficiency, fibrinogen deficiency, prothrombin deficiency, dilutional coagulopathy, thrombocytopenia, blood loss from high-risk surgeries, intracerebral hemorrhage, von Willebrand disease or von Willebrand disease with inhibitors to von Willebrand factor.
In another aspect, the present invention provides a method of treating a bleeding disorder in a subject in need thereof, the method comprising administering to the subject a therapeutically effective amount of a platelet population, wherein the platelets in the platelet population have a higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of platelets in a control platelet population.
In one embodiment, the platelets in the population of platelets are activated. In another embodiment, the platelets in the population of platelets are non-activated. In one embodiment, the platelets in the population of platelets are coated.
In one embodiment, the platelets in the platelet population have about a 2-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of platelets in a control platelet population. In one embodiment, the platelets in the platelet population have about a 5-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of platelets in a control platelet population. In one embodiment, the platelets in the platelet population have about a 10-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of platelets in a control platelet population. In another embodiment, the platelets in the platelet population have about a 20-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of platelets in a control platelet population. In one embodiment, the platelets in the platelet population have about a 30-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of platelets in a control platelet population. In another embodiment, the platelets in the platelet population have about a 40-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of platelets in a control platelet population.
In one embodiment, the platelets in the control platelet population are platelets not exposed to rFVIIa. In one embodiment, the platelets in the platelet population have a rFVIIa binding constant of about 50 to 400 nM. In another embodiment, the platelets in the platelet population have a rFVIIa binding constant of about 25 to 1100 nM.
In one embodiment, the bleeding disorder is hemophilia, blood loss from trauma, FVII deficiency, FV deficiency, FX deficiency, FXI deficiency, FXIII deficiency, fibrinogen deficiency, prothrombin deficiency, dilutional coagulopathy, thrombocytopenia, blood loss from high-risk surgeries, intracerebral hemorrhage, von Willebrand disease or von Willebrand disease with inhibitors to von Willebrand factor.
In one embodiment, the subject is a human.
In another aspect, the present invention provides a method of treating a bleeding disorder in a subject in need thereof, the method comprising administering a therapeutically effective amount of rFVIIa to the subject, wherein (a) a sample of platelets derived from the subject was obtained; (b) a platelet population from the sample was incubated with rFVIIa; and (c) platelets having a high binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of a control platelet population, were detected in the platelet population.
In another aspect, the present invention provides a method of treating a bleeding disorder in a subject in need thereof, the method comprising administering a therapeutically effective amount of an alternative therapy to the subject, wherein (a) a sample of platelets derived from the subject was obtained; (b) a platelet population from the sample was incubated with rFVIIa; and (c) platelets having a high binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of a control platelet population, were detected in the platelet population.
In another aspect, the present invention provides a method of treating a bleeding disorder in a subject in need thereof, the method comprising administering a therapeutically effective amount of an alternative therapy to the subject, wherein (a) a sample of platelets derived from the subject was obtained; (b) a platelet population from the sample was incubated with rFVIIa; and (c) platelets having a low binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of a control platelet population, were detected in the platelet population.
In one embodiment, the detection is by flow cytometry. In one embodiment, the platelets are activated. In another embodiment, the platelets are non-activated. In one embodiment, the platelets are coated.
In one embodiment, the control platelet population is a platelet population not exposed to rFVIIa.
In one embodiment the control platelet population has a rFVIIa binding constant of about 200 nM.
In one embodiment, the platelets having a high binding capacity to rFVIIa have about a 25-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of a control platelet population. In another embodiment, the platelets having a high binding capacity to rFVIIa have about a 35-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of a control platelet population.
In one embodiment, the platelets having a low binding capacity to rFVIIa have about a 5-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of a control platelet population. In another embodiment, the platelets having a low binding capacity to rFVIIa have about a 10-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of a control platelet population.
In one embodiment, the sample of platelets is obtained from a blood sample or a serum sample from the subject. In one embodiment, the sample of platelets is a fresh sample, a concentrate, a preserved sample, a rehydrated lyophilized sample, or a frozen sample.
In one embodiment, the bleeding disorder is hemophilia. In one embodiment, the hemophilia is hemophilia A or hemophilia B. In another embodiment, the hemophilia A is congenital hemophilia A with inhibitors or acquired hemophilia A with inhibitory auto antibodies to FVIII, and the hemophilia B is congenital hemophilia B with inhibitors or acquired hemophilia B with inhibitory auto antibodies to FIX.
In one embodiment, the subject does not have an unacceptable risk of thrombosis. In another embodiment, the subject has an unacceptable risk of thrombosis.
In one embodiment, the bleeding disorder is a non-hemophilia bleeding disorder. In one embodiment, the non-hemophilia bleeding disorder is blood loss from trauma, FVII deficiency, FV deficiency, FX deficiency, FXI deficiency, FXIII deficiency, fibrinogen deficiency, prothrombin deficiency, dilutional coagulopathy, thrombocytopenia, blood loss from high-risk surgeries, intracerebral hemorrhage, von Willebrand disease or von Willebrand disease with inhibitors to von Willebrand factor.
In one embodiment, the alternative therapy is Prothrombin Complex Concentrate or activated Prothrombin Complex Concentrate. In one embodiment, the activated Prothrombin Complex Concentrate is FEIBA.
In one embodiment, the alternative therapy is BeneFix®, Kogenate® FS, Recombinate, Advate®, Helixate® FS, Koāte®-DVI, Stimate®, DDAVP®, Bebulin, Hemofil M®, cryoprecipitated antihaemophilic factor (AHF), or fresh frozen plasma (FFP).
In another embodiment, the alternative therapy is recombinant porcine FVIII, recombinant FV variants, recombinant FVIIa variants, recombinant FXa variants, FXIII, prothrombin, fibrinogen, a mix of coagulation factors, antibodies mimicking FVIII, peptides mimicking FVIII, compounds mimicking FVIII, peptide inhibitors of TFPI, antibody inhibitors of TFPI, compounds inhibiting TFPI or compounds inhibiting anti-coagulant proteins.
In one embodiment, the subject is a human.
The invention further provides a method of treating a bleeding disorder in a subject in need thereof. The method comprises administering to the subject a therapeutically effective amount of a platelet population, wherein platelets in the platelet population demonstrate at least a 15-fold higher rFVIIa relative fluorescence after exposure to 100 nM rFVIIa. In various embodiments, platelet population comprises (i) non-activated platelets demonstrating at least a 25-fold higher rFVIIa relative fluorescence after exposure to 100 nM rFVIIa and/or (ii) activated platelets demonstrating at least a 20-fold higher rFVIIa relative fluorescence (e.g., a least a 30-fold higher rFVIIa relative fluorescence) after exposure to 100 nM rFVIIa.
Also provided is a method of treating a bleeding disorder in a subject in need thereof, the method comprising administering a therapeutically effective amount of rFVIIa to the subject, wherein a) a sample of platelets derived from the subject was obtained; b) a non-activated platelet population from the sample was incubated with rFVIIa; and c) platelets demonstrating at least a 15-fold higher, optionally at least a 25-fold higher, rFVIIa relative fluorescence after exposure to 100 nM rFVIIa were detected in the platelet population. Alternatively, the method comprises administering a therapeutically effective amount of rFVIIa to the subject, wherein a) a sample of platelets derived from the subject was obtained; b) an activated platelet population from the sample was incubated with rFVIIa; and c) platelets demonstrating at least a 20-fold higher, optionally at least a 30-fold higher, rFVIIa relative fluorescence after exposure to 100 nM rFVIIa were detected in the platelet population. The invention also provides a method of treating a bleeding disorder in a subject in need thereof, the method comprising administering a therapeutically effective amount of an alternative therapy to the subject, wherein a) a sample of platelets derived from the subject was obtained; b) a non-activated platelet population from the sample was incubated with rFVIIa; and c) platelets demonstrating an 8-fold higher rFVIIa relative fluorescence or less, optionally a 5-fold higher rFVIIa relative fluorescence or less, after exposure to 100 nM rFVIIa were detected in the platelet population. Alternatively, the method comprises administering a therapeutically effective amount of an alternative therapy to the subject, wherein a) a sample of platelets derived from the subject was obtained; b) an activated platelet population from the sample was incubated with rFVIIa; and c) platelets demonstrating a 9-fold higher rFVIIa relative fluorescence or less, optionally a 5-fold higher rFVIIa relative fluorescence or less, after exposure to 100 nM rFVIIa were detected in the platelet population.
A method of treating a bleeding disorder in a subject in need thereof also is contemplated, wherein the method comprises administering a therapeutically effective amount of rFVIIa to a subject having platelets that demonstrate at least a 3.5-fold increase in binding capacity upon dual-agonist activation compared to rFVIIa binding capacity of non-activated platelets from the subject. A method of treating a bleeding disorder in a subject in need thereof is further provided wherein the method comprises administering a therapeutically effective amount of an alternative therapy to a subject having platelets that demonstrate a 1.3-fold increase in binding capacity or less upon dual-agonist activation compared to rFVIIa binding capacity of non-activated platelets from the subject.
The foregoing summary is not intended to define every aspect of the invention, and additional aspects are described in other sections, such as the Detailed Description. The entire document is intended to be related as a unified disclosure, and it should be understood that all combinations of features described herein are contemplated, even if the combination of features are not found together in the same sentence, or paragraph, or section of this document. For example, features of the invention described with respect to a method of treating a bleeding disorder also apply to methods of determining whether a subject is a candidate for rFVIIa treatment, and vice versa. Similarly, features of the invention described with respect to an isolated platelet subpopulation also apply to methods of treating a bleeding disorder or a method of determining whether a subject is a candidate for rFVIIa treatment.
The term “N7” designates the drugs Novoseven® and Novoseven® RT. Novoseven® and Novoseven® RT are recombinant human Factor VIIa (rFVIIa), intended for promoting hemostasis by activating the extrinsic pathway of the coagulation cascade. Dosage and methods of administration of Novoseven® and Novoseven® RT are known to one of skill in the art. For more information, see, e.g., www.novosevenrt.com/.
The term “BAX817” designates the drug BAX817. BAX817 is recombinant Factor VIIa therapy, intended for treating acute bleedings in subjects with hemophilia A or B with Factor VIII or Factor IX inhibitors.
The term “rFVIIa” designates recombinant Factor VIIa. Indications, dosage and methods of administration of rFVIIa are known to one of skill in the art (see e.g., Ng and Lee, 2006, Vasc Health Risk Manag., 2(4): 433-440; see also Abshire and Kenet, 2004, J Thromb Haemost., 2(6): 899-909.)
The term “non-hemophilia bleeding disorder” designates a bleeding disorder that is not hemophilia (e.g., not hemophilia A, hemophilia B, hemophilia A with inhibitors, hemophilia B with inhibitors).
An “unacceptable risk of thrombosis” is a risk that is not medically appropriate in view of the potential benefit to the patient.
The term “coated,” as applied to coated platelets, represents a subpopulation of cells observed after dual agonist stimulation of platelets with collagen (or a collagen receptor agonist (e.g., convulxin)) and thrombin. These platelets retain on their surface high levels of several procoagulant proteins, including fibrinogen, von Willebrand factor, fibronectin, factor V and thrombospondin. For additional information, see e.g., Dale G L., 2005, J Thromb Haemost. (10):2185-92. rFVIIa has been shown to preferentially bind to the “coated” platelet population emerging after activation with thrombin and convulxin, a GPVI agonist (Kjalke M., 2007, J Thromb Haemost. (5):774-80.). It has also been shown that a “coated” platelet sub-population exposes high levels of Factor V, fibrinogen/fibrin, vWF (von Willebrand Factor), fibronectin, negatively charged phospholipids (see Kjalke et al., JTH 2007; 5: 774-80). In various embodiments, platelets that are not coated are activated platelets lacking fibrinogen on the platelet surface (or lacking more fibrinogen than naturally found on non-activated platelets).
A “control platelet population” is, in various aspects, a platelet population that is not exposed to rFVIIa.
The singular forms “a,” “an,” and “the” include plural reference unless the context clearly dictates otherwise. The term “or” should be understood to encompass items in the alternative or together, unless context unambiguously requires otherwise. If aspects of the invention are described as “comprising” a feature, embodiments also are contemplated “consisting of” or “consisting essentially of” the feature.
The term “about” is used herein to mean approximately, in the region of, roughly, or around. When the term “about” is used in conjunction with a numerical range, it modifies that range by extending the boundaries above and below the numerical values set forth. In general, the term “about” is used herein to modify a numerical value above and below the stated value by a variance of 20%.
The invention relates to a platelet subpopulation with high binding capacity to recombinant activated factor VII (rFVIIa), and its use for the treatment of blood disorders. The invention also relates to a method for determining whether a subject is a candidate for treatment with rFVIIa or alternative therapies. Patients respond differently to rFVIIa. The methods described herein provide a means for selecting patients with an increased likelihood of responding to rFVIIa treatment, as well as patients for which alternative therapies may be more beneficial.
In one aspect, the invention provides a method of treating a bleeding disorder in a subject in need thereof. The method comprises administering a therapeutically effective amount of rFVIIa to the subject, wherein (a) a sample of platelets derived from the subject was obtained; (b) a platelet population from the sample was incubated with rFVIIa; and (c) a subpopulation of platelets having at least a 4-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of the other platelets in the platelet population, was detected in the platelet population. Alternatively, the method comprises administering a therapeutically effective amount of rFVIIa to the subject, wherein (a) a sample of platelets derived from the subject was obtained; (b) a platelet population from the sample was incubated with rFVIIa; and (c) platelets having a high binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of a control platelet population, were detected in the platelet population.
Also included is recombinant FVIIa for use in treating (or for use in the preparation of a medicament for treating) a bleeding disorder in a subject in need thereof having a subpopulation of platelets (i) having at least a 4-fold higher binding capacity to rFVIIa as compared to the binding capacity to rFVIIa of the other platelets in the platelet population and/or (ii) having a higher binding capacity to rFVIIa as compared to the binding capacity to rFVIIa of a control platelet population. Indeed, the invention include a method for treating a bleeding disorder comprising administering rFVIIa to a subject in need thereof and having a subpopulation of platelets (i) having at least a 4-fold higher binding capacity to rFVIIa as compared to the binding capacity to rFVIIa of the other platelets in the platelet population and/or (ii) having a higher binding capacity to rFVIIa as compared to the binding capacity to rFVIIa of a control platelet population.
In another aspect, the invention provides a method of treating a bleeding disorder in a subject in need thereof, the method comprising administering a therapeutically effective amount of an alternative therapy to the subject, wherein (a) a sample of platelets derived from the subject was obtained; (b) a platelet population from the sample was incubated with rFVIIa; and (c) a subpopulation of platelets having at least a 4-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of the other platelets in the platelet population, was not detected in the platelet population. Alternatively, the method comprises administering a therapeutically effective amount of an alternative therapy to the subject, wherein (a) a sample of platelets derived from the subject was obtained; (b) a platelet population from the sample was incubated with rFVIIa; and (c) platelets having a high binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of a control platelet population, were not detected in the platelet population.
Also included is an alternative therapy for use in treating (or for use in the preparation of a medicament for treating) a bleeding disorder in a subject in need thereof lacking a subpopulation of platelets (i) having at least a 4-fold higher binding capacity to rFVIIa as compared to the binding capacity to rFVIIa of the other platelets in the platelet population and/or (ii) having a higher binding capacity to rFVIIa as compared to the binding capacity to rFVIIa of a control platelet population. Indeed, the invention includes a method for treating a bleeding disorder comprising administering an alternative therapy to a subject in need thereof and lacking a subpopulation of platelets (i) having at least a 4-fold higher binding capacity to rFVIIa as compared to the binding capacity to rFVIIa of the other platelets in the platelet population and/or (ii) having a higher binding capacity to rFVIIa as compared to the binding capacity to rFVIIa of a control platelet population.
In yet another aspect, the invention provides a method of treating a bleeding disorder in a subject in need thereof, the method comprising administering to the subject a therapeutically effective amount of a platelet population containing (e.g., enriched with) a subpopulation of platelets having at least a 4-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of the other platelets in the platelet population. Alternatively, the method comprises administering to the subject a therapeutically effective amount of a platelet population comprising platelets having a higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of platelets in a control platelet population. For example, in various embodiments, the platelets in the platelet population have at least a 0.25 fold, 0.5-fold, 1-fold, 1.5-fold, 2-fold, 2.5 fold, 3-fold, 3.5-fold, 4-fold, 4.5-fold, 5-fold, 5.5-fold, 6-fold, 6.5-fold, 7-fold, 7.5-fold, 8-fold, 8.5-fold, 9-fold, or higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of platelets in a control platelet population (or other platelets in the platelet population). The platelets in the control platelet population are platelets not exposed to rFVIIa.
Thus, in various aspects, a sample of platelets derived from the subject is obtained and characterized for rFVIIa binding. In one embodiment, the sample of platelets is obtained from a blood sample from the subject. In another embodiment, the sample of platelets is obtained from a serum sample from the subject. The sample of platelets is, in various embodiments, a fresh sample, a concentrate, a preserved sample, a rehydrated lyophilized sample, or a frozen sample. In methods comprising administering a platelet population or subpopulation to a subject, the platelet population or subpopulation is from the subject, although platelets administered to a subject in the context of the invention also may originate from one or more other donors.
In various embodiments, a platelet population from the sample derived from the subject is incubated with rFVIIa. The concentration of rFVIIa is, e.g., about 5 nM, 10 nM, 20 nM, 30 nM, 40 nM, 50 nM, 100 nM, 200 nM, 300 nM, 400 nM, 500 nM, 600 nM, 700 nM, 800 nM, 900 nM, 1000 nM, 1100 nM, 1200 nM, 1300 nM, 1400 nM, 1500 nM, 1600 nM, 1700 nM, 1800 nM, 1900 nM, 2000 nM, 3000 nM, 4000 nM, 5000 nM, 6000 nM, or more. The platelet population may be incubated with rFVIIa for any suitable amount of time, e.g., at least or no more than 7, 10, 12, 15, 20, or 30 minutes.
Detection of platelets with desired characteristics is achieved by any method known to one of skill in the art, such as a method that detects rFVIIa-bound platelets. Detection is, in various embodiments, performed by flow cytometry, immunofluorescence, microscopy (such as, but not limited to, electron microscopy or confocal laser scanning microscopy (CLSM or LSCM)), or immunoassay (such as, but not limited to, cell-based enzyme-linked immunosorbent assay). The rFVIIa binding capacity of platelets is optionally measured through, e.g., detection of fluorescence intensity. In one embodiment, the fluorescence intensity is proportional to the amount of rFVIIa bound to the platelets.
In one embodiment, the platelets in the platelet population (or subpopulation of platelets, or control platelet population) are activated. The activated platelets may be coated or not coated. In another embodiment, the platelets in the platelet population (or subpopulation of platelets, or control platelet population) are non-activated. In one embodiment, the platelets in the platelet population (or subpopulation of platelets, or control platelet population) are coated. In another embodiment, the platelets in the platelet population (or subpopulation of platelets, or control platelet population) are not coated.
In one embodiment, the platelets in the platelet population or control platelet population have a rFVIIa binding constant of about 25 to 1100 nM. In another embodiment, the platelets in the platelet population or control platelet population have a rFVIIa binding constant of about 50 to 400 nM. In further embodiments, the platelets in the platelet population or control platelet population have a rFVIIa binding constant of about 10 nM, about 20 nM, about 30 nM, about 40 nM, about 50 nM, about 60 nM, about 70 nM, about 80 nM, about 90 nM, about 100 nM, about 200 nM, about 300 nM, about 400 nM, about 500 nM, about 600 nM, about 700 nM, about 800 nM, about 900 nM, about 1000 nM, about 1100 nM, about 1200 nM, about 1300 nM, about 1400 nM, about 1500 nM, about 1600 nM, about 1700 nM, about 1800 nM, about 1900 nM, about 2000 nM, about 3000 nM, about 4000 nM, or about 5000 nM, about 6000 nM, about 7000 nM, about 8000 nM, about 9000 nM, about 10,000 nM, or more.
In other embodiments, the platelets in the platelet population or control platelet population have a rFVIIa binding constant of about 10 nM to 30 nM, about 20 nM to 40 nM, about 30 nM to 50 nM, about 40 nM to 60 nM, about 50 nM to 70 nM, about 60 nM to 80 nM, about 70 nM to 90 nM, about 80 nM to 100 nM, 90 nM to 110 nM, about 100 nM to 120 nM, about 110 nM to 130 nM, about 120 nM to 140 nM, about 130 nM to 150 nM, about 140 nM to 160 nM, about 150 nM to 170 nM, about 160 nM to 180 nM, about 170 nM to 190 nM, about 180 nM to 200 nM, about 190 nM to 210 nM, about 200 nM to 220 nM, about 210 nM to 230 nM, about 220 nM to 240 nM, about 230 nM to 250 nM, about 240 nM to 260 nM, about 250 nM to 270 nM, about 260 nM to 280 nM, about 270 nM to 290 nM, about 280 nM to 300 nM, about 290 nM to 310 nM, about 300 nM to 320 nM, about 310 nM to 330 nM, about 320 nM to 340 nM, about 330 nM to 350 nM, about 340 nM to 360 nM, about 350 nM to 370 nM, about 360 nM to 380 nM, about 370 nM to 390 nM, about 380 nM to 400 nM, about 390 nM to 410 nM, about 400 nM to 450 nM, about 450 nM to 500 nM, about 500 nM to 550 nM, about 550 nM to 600 nM, about 600 nM to 650 nM, about 650 nM to 700 nM, about 700 nM to 750 nM, about 750 nM to 800 nM, about 800 nM to 850 nM, about 850 nM to 900 nM, about 900 nM to 950 nM, about 950 nM to 1000 nM, about 1000 nM to 1050 nM, about 1050 nM to 1100 nM, about 1100 nM to 1150 nM, about 1150 nM to 1200 nM, about 1200 nM to 1250 nM, about 1250 nM to 1300 nM, about 1300 nM to 1350 nM, about 1350 nM to 1400 nM, about 1400 nM to 1450 nM, or about 1450 nM to 1500 nM, or any range in between.
In one embodiment, the platelets in the subpopulation of platelets or the platelets having a higher rFVIIa binding capacity than a control population have a rFVIIa binding constant of about 10 nM, about 20 nM, about 30 nM, about 40 nM, about 50 nM, about 60 nM, about 70 nM, about 80 nM, about 90 nM, about 100 nM, about 200 nM, about 300 nM, about 400 nM, about 500 nM, about 600 nM, about 700 nM, about 800 nM, about 900 nM, about 1000 nM, about 1100 nM, about 1200 nM, about 1300 nM, about 1400 nM, about 1500 nM, about 1600 nM, about 1700 nM, about 1800 nM, about 1900 nM, about 2000 nM, about 3000 nM, about 4000 nM, about 5000 nM, about 6000 nM, about 7000 nM, about 8000 nM, about 9000 nM, about 10,000 nM, or more.
In various embodiments, the platelets in the subpopulation of platelets or the platelets having a higher rFVIIa binding capacity than a control population have a rFVIIa binding constant of about 10 nM to 30 nM, about 20 nM to 40 nM, about 30 nM to 50 nM, about 40 nM to 60 nM, about 50 nM to 70 nM, about 60 nM to 80 nM, about 70 nM to 90 nM, about 80 nM to 100 nM, 90 nM to 110 nM, about 100 nM to 120 nM, about 110 nM to 130 nM, about 120 nM to 140 nM, about 130 nM to 150 nM, about 140 nM to 160 nM, about 150 nM to 170 nM, about 160 nM to 180 nM, about 170 nM to 190 nM, about 180 nM to 200 nM, about 190 nM to 210 nM, about 200 nM to 220 nM, about 210 nM to 230 nM, about 220 nM to 240 nM, about 230 nM to 250 nM, about 240 nM to 260 nM, about 250 nM to 270 nM, about 260 nM to 280 nM, about 270 nM to 290 nM, about 280 nM to 300 nM, about 290 nM to 310 nM, about 300 nM to 320 nM, about 310 nM to 330 nM, about 320 nM to 340 nM, about 330 nM to 350 nM, about 340 nM to 360 nM, about 350 nM to 370 nM, about 360 nM to 380 nM, about 370 nM to 390 nM, about 380 nM to 400 nM, about 390 nM to 410 nM, about 400 nM to 450 nM, about 450 nM to 500 nM, about 500 nM to 550 nM, about 550 nM to 600 nM, about 600 nM to 650 nM, about 650 nM to 700 nM, about 700 nM to 750 nM, about 750 nM to 800 nM, about 800 nM to 850 nM, about 850 nM to 900 nM, about 900 nM to 950 nM, about 950 nM to 1000 nM, about 1000 nM to 1050 nM, about 1050 nM to 1100 nM, about 1100 nM to 1150 nM, about 1150 nM to 1200 nM, about 1200 nM to 1250 nM, about 1250 nM to 1300 nM, about 1300 nM to 1350 nM, about 1350 nM to 1400 nM, about 1400 nM to 1450 nM, or about 1450 nM to 1500 nM, or any range in between.
Recombinant FVIIa binding capacity is compared to other platelets in the platelet population and/or platelets in a control platelet population (platelets that have not been exposed to rFVIIa). In an exemplary embodiment, binding capacity is determined by, e.g., measuring fluorescence intensity (optionally via flow cytometry), which is proportional to the amount of rFVIIa bound to the platelets. Platelets are identified for flow cytometry by their forward and side scatter light properties, and by expression of CD61, a platelet-specific surface marker protein. Activated platelets are indentified by using increase of surface-bound CD62P (P-selectin), and coated platelets are identified by using fibrinogen as surface marker. These surface-bound proteins can be identified using fluorochrome-conjugated antibodies specific for the respective protein. By using multiparameter flow cytometry, the platelets binding rFVIIa and, for example, exposing CD62P and fibrinogen can be detected. Platelet populations and subpopulations can be identified using signal intensity of any relevant channel by making so-called dot-plots for data anylsis. Additionally, platelets can be plotted in a histogram showing the distribution of the platelets in terms of amount of rFVIIa bound to the surface. A subpopulation can be identified if two separate peaks can be observed, or if a “shoulder” is visible. Especially in case of a “shoulder” in the histogram, a dot-plot can be made to add another criterion for discrimination, e.g. side-scatter or CD62P. A subpopulation demonstrating a higher median fluorescence intensity than the median fluorescence intensity of the remainder of the platelet population (or a control platelet population), and which optionally also represents at least about 2% of the total platelet population examined, is a subpopulation of platelets having a higher rFVIIa binding capacity (i.e., binds more rFVIIa) compared to the major population (or a control population).
In one embodiment, the platelet population contains a subpopulation of platelets having about a 0.1-fold, about a 0.15-fold, about a 0.2-fold, about a 0.25-fold, about a 0.3-fold, about a 0.4-fold, about a 0.5 fold, about a 0.6-fold, about a 0.7-fold, about a 0.8-fold, about a 0.9-fold, about a 1-fold, about a 1.5-fold, about a 2 fold, about a 2.5-fold, about a 3-fold, about a 3.5-fold, about a 4-fold, about a 4.5-fold, about a 5-fold, about a 5.5-fold, about a 6-fold, about a 6.5-fold, about a 7-fold, about a 7.5-fold, about a 8-fold, about a 8.5-fold, or about a 9-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of the other platelets in the platelet population. In another embodiment, the platelet population contains a subpopulation of platelets having at least about a 10-fold, about a 11-fold, about a 12 fold, about a 13-fold, about a 14-fold, about a 15-fold, about a 16-fold, about a 17-fold, about a 18-fold, about a 19-fold, about a 20-fold, about a 21-fold, about a 22-fold, about a 23-fold, about a 24-fold, about a 25-fold, about a 26-fold, about a 27-fold, about a 28-fold, about a 29-fold, about a 30-fold, about a 31-fold, about a 32-fold, about a 33-fold, about a 34-fold, about a 35-fold, about a 36-fold, about a 37-fold, about a 38-fold, about a 39-fold, about a 40-fold, about a 41-fold, about a 42-fold, about a 43-fold, about a 44-fold, about a 45-fold, about a 46-fold, about a 47-fold, about a 48-fold, about a 49-fold, about a 50-fold, about a 51-fold, about a 52-fold, about a 53-fold, about a 54-fold, about a 55-fold, about a 56-fold, about a 57-fold, about a 58-fold, about a 59-fold, about a 60-fold, about a 70-fold, about a 80-fold, about a 90-fold, about a 100-fold, about a 150-fold, about a 200-fold, about a 250-fold, about a 300-fold, about a 350-fold, about a 400-fold, about a 450-fold, or about a 500-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of the other platelets in the platelet population.
In another embodiment, the platelets in the subpopulation have about a 0.3-fold to 2.5-fold higher binding capacity (e.g., about a 0.3-fold to 2.4-fold higher binding capacity), about a 4-fold to 33-fold higher binding capacity, or about a 5-fold to 37-fold higher binding capacity, as compared to the binding capacity to rFVIIa of platelets in the rest of the population.
In another embodiment, the platelet population contains a subpopulation of platelets having about a 0.1-fold to 0.3-fold, about a 0.2-fold to 0.4-fold, about a 0.3-fold to 0.5-fold, about a 0.4-fold to 0.6-fold, about a 0.5-fold to 0.7-fold, about a 0.6-fold to 0.8-fold, about a 0.7-fold to 0.9-fold, about a 0.8-fold to 1.0-fold, about a 0.9-fold to 1.1-fold, about a 1-fold to 1.5-fold, about a 1.25-fold to 1.75-fold, about a 1.5-fold to 2-fold, about a 1.75-fold to 2.25-fold, about a 2-fold to 2.5-fold, about a 2.25-fold to 2.75-fold, about a 2.5-fold to 3-fold, about a 2.75-fold to 3.25-fold, about a 3-fold to 4-fold, about a 3.5-fold to 4.5-fold, about a 4-fold to 5-fold, about a 4.5-fold to 5.5-fold, about a 5-fold to 6-fold, about a 6-fold to 8-fold, about a 8-fold to 10-fold, about a 10-fold to 12-fold, about a 12-fold to 14-fold, about a 14-fold to 16-fold, about a 16-fold to 18-fold, about a 18-fold to 20-fold, about a 20-fold to 25-fold, about a 25-fold to 30-fold, about a 30-fold to 40-fold, about a 40-fold to 50-fold, about a 50-fold to 70-fold, about a 70-fold to 90-fold, about a 90-fold to 100-fold, about a 100-fold to 120-fold, about a 120-fold to 140-fold, about a 140-fold to 160-fold, about a 1-fold to 20-fold, about a 10-fold to 30-fold, about a 20-fold to 40-fold, about a 30-fold to 50-fold, about a 40-fold to 60-fold, about a 50-fold to 80-fold, about a 60-fold to 80-fold, about a 70-fold to 90-fold, about a 80-fold to 100-fold, about a 100-fold to 150-fold, about a 130-fold to 180-fold, or any range in between, higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of the other platelets in the platelet population.
In one embodiment, the platelets having a high binding capacity to rFVIIa compared to a control population have about a 0.1-fold, about a 0.15-fold, about a 0.2-fold, about a 0.25-fold, about a 0.3-fold, about a 0.4-fold, about a 0.5-fold, about a 0.6-fold, about a 0.7-fold, about a 0.8-fold, about a 0.9-fold, about a 1-fold, about a 1.5-fold, about a 2 fold, about a 2.5-fold, about a 3-fold, about a 3.5-fold, about a 4-fold, about a 4.5-fold, about a 5-fold, about a 5.5-fold, about a 6-fold, about a 6.5-fold, about a 7-fold, about a 7.5-fold, about a 8-fold, about a 8.5-fold, or about a 9-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of platelets in a control platelet population. In another embodiment, the platelets having a high binding capacity to rFVIIa have at least about a 10-fold, about a 11-fold, about a 12-fold, about a 13-fold, about a 14-fold, about a 15-fold, about a 16-fold, about a 17-fold, about a 18-fold, about a 19-fold, about a 20-fold, about a 21-fold, about a 22-fold, about a 23-fold, about a 24-fold, about a 25-fold, about a 26-fold, about a 27-fold, about a 28-fold, about a 29-fold, about a 30-fold, about a 31-fold, about a 32-fold, about a 33-fold, about a 34-fold, about a 35-fold, about a 36-fold, about a 37-fold, about a 38-fold, about a 39-fold, about a 40-fold, about a 41-fold, about a 42-fold, about a 43-fold, about a 44-fold, about a 45-fold, about a 46-fold, about a 47-fold, about a 48-fold, about a 49-fold, about a 50-fold, about a 51-fold, about a 52-fold, about a 53-fold, about a 54-fold, about a 55-fold, about a 56-fold, about a 57-fold, about a 58-fold, about a 59-fold, about a 60-fold, about a 70-fold, about a 80-fold, about a 90-fold, about a 100-fold, about a 150-fold, about a 200-fold, about a 250-fold, about a 300-fold, about a 350-fold, about a 400-fold, about a 450-fold, or about a 500-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of platelets in a control platelet population.
In another embodiment, the platelets in the platelet population having a high rFVIIa binding capacity have about a 0.3-fold to 2.5-fold higher binding capacity (e.g., about a 0.3-fold to 2.4-fold higher binding capacity), about a 4-fold to 33-fold higher binding capacity, or about a 5-fold to 37-fold higher binding capacity, as compared to the binding capacity to rFVIIa of platelets in a control platelet population.
In another embodiment, the platelets in the platelet population having a high binding capacity to rFVIIa have about a 0.1-fold to 0.3-fold, about a 0.2-fold to 0.4-fold, about a 0.3-fold to 0.5-fold, about a 0.4-fold to 0.6-fold, about a 0.5-fold to 0.7-fold, about a 0.6-fold to 0.8-fold, about a 0.7-fold to 0.9-fold, about a 0.8-fold to 1.0-fold, about a 0.9-fold to 1.1-fold, about a 1-fold to 1.5-fold, about a 1.25-fold to 1.75-fold, about a 1.5-fold to 2-fold, about a 1.75-fold to 2.25-fold, about a 2-fold to 2.5-fold, about a 2.25-fold to 2.75-fold, about a 2.5-fold to 3-fold, about a 2.75-fold to 3.25-fold, about a 3-fold to 4-fold, about a 3.5-fold to 4.5-fold, about a 4-fold to 5-fold, about a 4.5-fold to 5.5-fold, about a 5-fold to 6-fold, about a 6-fold to 8-fold, about a 8-fold to 10-fold, about a 10-fold to 12-fold, about a 12-fold to 14-fold, about a 14-fold to 16-fold, about a 16-fold to 18-fold, about a 18-fold to 20-fold, about a 20-fold to 25-fold, about a 25-fold to 30-fold, about a 30-fold to 40-fold, about a 40-fold to 50-fold, about a 50-fold to 70-fold, about a 70-fold to 90-fold, about a 90-fold to 100-fold, about a 100-fold to 120-fold, about a 120-fold to 140-fold, about a 140-fold to 160-fold, about a 1-fold to 20-fold, about a 10-fold to 30-fold, about a 20-fold to 40-fold, about a 30-fold to 50-fold, about a 40-fold to 60-fold, about a 50-fold to 80-fold, about a 60-fold to 80-fold, about a 70-fold to 90-fold, about a 80-fold to 100-fold, about a 100-fold to 150-fold, about a 130-fold to 180-fold, or any range in between higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of platelets in a control platelet population. The “control” platelet population is a population not exposed to rFVIIa prior to examining binding characteristics.
In various embodiments, the platelet population contains a subpopulation of platelets having about a 50%, 75%, 100%, 125%, 150%, 175%, 200%, 300%, 400%, or a 500% higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of the other platelets in the platelet population. The platelets having a higher binding capacity to rFVIIa compared to platelets in a control population have about a 50%, 75%, 100%, 125%, 150%, 175%, 200%, 300%, 400%, or a 500% higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of the control platelet population.
In one embodiment, the platelet subpopulation with a higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of the other platelets in the platelet population, consists of at least 2% of the platelet population. In various embodiments, the platelet subpopulation represents (consists of) at least 0.5%, 1%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 40%, 50%, or more (e.g., 60%, 70%, 75%, 80%, 90%, 95%, or 100%) of the platelet population.
The invention also includes the subpopulation of platelets described herein. For example, the invention includes a subpopulation of platelets isolated from a platelet population, wherein the platelets in the subpopulation of platelets have at least a 4-fold higher binding capacity to rFVIIa as compared to the binding capacity to rFVIIa of the other platelets in the platelet population. Detection of the subpopulation and characterization of rFVIIa binding capacity is described above and applicable here. The platelets in the subpopulation of platelets are activated or non-activated. The platelets in the subpopulation also may be coated or not coated.
In various embodiments, the bleeding disorder is hemophilia (e.g., hemophilia with inhibitors or hemophilia without inhibitors). In various embodiments, the hemophilia is hemophilia A (e.g., hemophilia A with inhibitors) or hemophilia B (e.g., hemophilia B with inhibitors). The inhibitors are optionally to Factor VIII or Factor IX. In another embodiment, the hemophilia is acquired hemophilia. In one embodiment, the hemophilia is congenital hemophilia A with inhibitors or acquired hemophilia A with inhibitory auto antibodies to FVIII. In one embodiment, the hemophilia is congenital hemophilia B with inhibitors or acquired hemophilia B with inhibitory auto antibodies to FIX. In addition, the rFVIIa is optionally administered if the subject does not have an unacceptable risk of thrombosis.
In alternative embodiments, the bleeding disorder is a non-hemophilia bleeding disorder. In one embodiment, the bleeding disorder is blood loss from trauma or blood loss from surgery (e.g., high risk surgery). Other examples of bleeding disorders include, but are not limited to, FVII deficiency, FV deficiency, FX deficiency, FXI deficiency, FXIII deficiency, fibrinogen deficiency, prothrombin deficiency, dilutional coagulopathy, thrombocytopenia, and von Willebrand disease (e.g., von Willebrand disease with inhibitors to von Willebrand factor). In another embodiment, the bleeding disorder is intracerebral hemorrhage.
In one embodiment, the bleeding disorder is a congenital platelet function defect, including, but not limited to, platelet storage pool disorder, Glanzmann's thrombasthenia, or Bernard-Soulier syndrome. In one embodiment, the bleeding disorder is an acquired platelet function defect. In one embodiment, the bleeding disorder is a congenital deficiency of Factor II, Factor V, Factor VII, Factor X, or Factor XI. In one embodiment, the bleeding disorder is a neonatal or pediatric coagulopathy. In one embodiment, the bleeding disorder is a platelet function disorder. In another embodiment, the bleeding disorder is heparin-induced thrombocytopenia. In one embodiment, the bleeding disorder is disseminated intravascular coagulation. In other embodiments, the bleeding disorder is any disorder known to one of skill in the art (for additional information, see e.g., The Absite Review, by Steven M. Fiser, Lippincott Williams and Wilkins 2004).
In various aspects, the inventive method comprises administering to a subject a therapeutically effective amount of recombinant Factor VIla (rFVIIa). Examples of suitable rFVIIa include, but are not limited to, NovoSeven® (Novo Nordisk) and BAX817. The rFVIIa is optionally administered with, or part of a therapeutic regimen that also includes, FX, ATIII (antithrombin III), a combination of FX and ATIII, FII, FX, a combination of FII and FX, and platelet infusion (optionally infusion of platelets described herein).
In various aspects, the method comprises administering an alternative therapy, i.e., therapy other than rFVIIa. In one embodiment, the alternative therapy is a therapy that is used for treating a bleeding disorder and that is not rFVIIa (e.g., not rFVIIa as a single agent) or does not comprise rFVIIa, as determined by a person of skill in the art. For additional information on therapies to treat bleeding disorders, including dosage and administration, see e.g., The Absite Review, by Steven M. Fiser, Lippincott Williams and Wilkins 2004.
In one embodiment, the alternative therapy is a coagulation factor that is not recombinant rFVIIa, or a variant of a coagulation factor that is not recombinant rFVIIa. The coagulation factor is recombinant or non-recombinant, and is activated or non-activated. Exemplary non-FVIIa coagulation factors include, but are not limited, to FI (fibrinogen), FII (prothrombin), FIII (tissue factor), FIV, FV, FVa, FVIII, FIX, FX, FXa, FXI, FXIII, von Willebrand factor, prekallikrein, and high-molecular weight kininogen. In various embodiments, the alternative therapy is a mixture of coagulation factors, e.g., two, three, or more coagulation factors, one or more of which is a recombinant, activated, or non-activated coagulation factors.
In one embodiment, the alternative therapy is BeneFix® (recombinant Factor IX), Rixubis® (recombinant Factor IX) Kogenate® FS (recombinant Factor VIII), Recombinate (recombinant Factor VIII), Advate® (recombinant Factor VIII), Helixate® FS (recombinant Factor VIII), Koāte®-DVI (recombinant Factor VIII), Stimate® (desmopressin acetate), DDAVP® (desmopressin acetate), Bebulin (Factor IX Complex), cryoprecipitated antihaemophilic factor (AHF), Octanate® (human Factor VIII/von Willebrand Factor (VWF)), Hemofil M® (human factor VIII), or fresh frozen plasma (FFP) (or any combination of two or more of the foregoing). For additional information on therapies to treat bleeding disorders, including dosage and administration, see e.g., The Absite Review, by Steven M. Fiser, Lippincott Williams and Wilkins 2004.
The term “Benefix®” is a brand name for the drug Coagulation Factor IX (Recombinant). Indications, dosage and methods of administration of this drug are known to one of skill in the art. For additional information, see www.benefix.com.
“Rixubis®” is a brand name for a recombinant Factor IX product. For additional information, see www.rixubis.com.
The term “Kogenate® FS” is a brand name for a recombinant factor VIII product. Indications, dosage and methods of administration of this drug are known to one of skill in the art. For additional information, see www.kogenate.com.
The term “Recombinate” is a brand name for a drug that is a recombinant antihemophilic factor. Indications, dosage and methods of administration of this drug are known to one of skill in the art. For additional information, see www.recombinate.com.
The term “Advate®” designates a drug that is a recombinant antihemophilic factor, used to replace clotting factor VIII. Indications, dosage and methods of administration of this drug are known to one of skill in the art. For additional information, see www.advate.com.
The term “Helixate® FS” is a brand name for a drug that is a recombinant factor VIII treatment. Indications, dosage and methods of administration of this drug are known to one of skill in the art. For additional information, see www.helixatefs.com.
The term “Koāte®-DVI” is a brand name for a drug that is a human antihemophilic factor treatment. Indications, dosage and methods of administration of this drug are known to one of skill in the art. For additional information, see www.koate-dvi.com/.
The term “Stimate®” is a brand of desmopressin used to help stop bleeding in patients with von Willebrand's disease or mild hemophilia A. Indications, dosage and methods of administration of this drug are known to one of skill in the art. For additional information, see www.stimate.com/.
The term “DDAVP®” is a brand of desmopressin used to help stop bleeding in patients with von Willebrand's disease or mild hemophilia A. Indications, dosage and methods of administration of this drug are known to one of skill in the art.
The term “Bebulin” designates the drug Factor IX Complex. Indications, dosage and methods of administration of this drug are known to one of skill in the art. For additional information, see www.baxter.com.
The term “Hemofil M®” is a brand of antihemophilic human factor VIII. Indications, dosage and methods of administration of this drug are known to one of skill in the art. For additional information, see www.baxter.com.
In one embodiment, the alternative therapy is recombinant porcine FVIII a recombinant FV variant, a recombinant FVIIa variant, a recombinant FXa variant, FXIII, prothrombin, or fibrinogen. In another embodiment, the alternative therapy is a mix of coagulation factors, e.g., a mix of FX (plasma-derived or recombinant FX), FVIIa (plasma-derived or recombinant FVIIa), and antithrombin III (ATIII). Other suitable alternative therapies include, but are not limited to, antibodies mimicking FVIII, peptides mimicking FVIII, and compounds mimicking FVIII. In one embodiment, the alternative therapy is a peptide inhibitor of TFPI, an antibody inhibitor of TFPI, or a compound inhibiting TFPI. In another embodiment, the alternative therapy is compounds inhibiting anti-coagulant proteins or agents that reduce expression of anti-coagulant proteins.
In one embodiment, the alternative therapy is a molecule that can mimic a coagulation factor, a molecule that can mimic the activity of a coagulation factor, or a molecule which has procoagulation activity. In a further embodiment, the alternative therapy can be a mixture of molecules that mimic coagulation factors, or the activity of coagulation factors. In one embodiment, the molecule is a small molecule, a peptide, or an antibody or a fragment thereof.
In one embodiment, the alternative therapy is an inhibitor of an anti-coagulant. In one embodiment, the inhibitor can include, but is not limited to, a small molecule, a peptide, or an antibody. In one embodiment the anti-coagulant can include, but is not limited to protein C, heparin cofactor II, heparin cofactor III, anti-thrombin, protein Z, protein S, protein Z-related protease inhibitor, plasminogen, alpha 2-antiplasmin, tissue plasminogen activator, urokinase, plasminogen activator inhibitor-1, plasminogen activator inhibitor-2, or cancer procoagulant. In a further embodiment, the alternative therapy can be a mixture of inhibitors of an anti-coagulant.
In one embodiment, the alternative therapy is Prothrombin Complex Concentrate or activated Prothrombin Complex Concentrate. In one embodiment, the activated Prothrombin Complex Concentrate is FEIBA. The term “FEIBA” designates the drug Factor VIII Inhibitor Bypassing Complex, or Anti-Inhibitor Coagulant Complex. Indications, dosage and methods of administration of this drug are known to one of skill in the art. For additional information, see www.feiba.com.
In one embodiment, the subject is an animal, such as a mammal. In various embodiments, the subject is a human. In some embodiments, the subject is a rodent, such as a mouse or a rat. In some embodiments, the subject is a cow, pig, sheep, goat, cat, horse, dog, and/or any other species of animal used as livestock or kept as pets.
Optionally, the subject is suspected to have a bleeding disorder, has been diagnosed with a bleeding disorder, is predisposed to developing a bleeding disorder, or is at risk of developing a bleeding disorder. In one embodiment, the subject is being treated for a bleeding disorder before initiation of the inventive method. In other embodiments, the subject has not previously been treated for a bleeding disorder prior to the inventive method.
The subject has a risk of thrombosis or does not have a risk of thrombosis. In one embodiment, the subject has an unacceptable risk of thrombosis. In another embodiment, the subject does not have an unacceptable risk of thrombosis (although this is not required). For example, in various embodiments, the bleeding disorder is a non-hemophilia bleeding disorder, and rFVIIa is administered if the subject does not have an unacceptable risk of thrombosis.
The invention provides a method of treating a bleeding disorder in a subject in need thereof, the method comprising administering a therapeutically effective amount of rFVIIa to the subject, wherein (a) a sample of platelets derived from the subject was obtained; (b) a platelet population from the sample was incubated with rFVIIa; and (c) platelets having a high binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of a control platelet population, were detected in the platelet population. The invention also provides a method of treating a bleeding disorder in a subject in need thereof, the method comprising administering a therapeutically effective amount of rFVIIa to the subject, wherein (a) a sample of platelets derived from the subject was obtained; (b) a platelet population from the sample was incubated with rFVIIa; and (c) platelets having a low binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of a control platelet population, were detected in the platelet population.
In another aspect, the invention provides a method of treating a bleeding disorder in a subject in need thereof, the method comprising administering a therapeutically effective amount of an alternative therapy to the subject, wherein (a) a sample of platelets derived from the subject was obtained; (b) a platelet population from the sample was incubated with rFVIIa; and (c) platelets having a high binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of a control platelet population, were detected in the platelet population. The invention also provides a method of treating a bleeding disorder in a subject in need thereof, the method comprising administering a therapeutically effective amount of an alternative therapy to the subject, wherein (a) a sample of platelets derived from the subject was obtained; (b) a platelet population from the sample was incubated with rFVIIa; and (c) platelets having a low binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of a control platelet population, were detected in the platelet population.
In various embodiments, the platelets having a high binding capacity to rFVIIa have about a 25-fold higher or about a 35-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of a control platelet population. In various embodiments, the platelets having a low binding capacity to rFVIIa have about a 5-fold higher or about a 10-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of a control platelet population.
In one embodiment, the platelets having a low binding capacity to rFVIIa have about a 0.1-fold, about a 0.15-fold, about a 0.2-fold, about a 0.25-fold, about a 0.3-fold, about a 0.4-fold, about a 0.5 fold, about a 0.6-fold, about a 0.7-fold, about a 0.8-fold, about a 0.9-fold, about a 1-fold, about a 1.5-fold, about a 2 fold, about a 2.5-fold, about a 3-fold, about a 3.5-fold, about a 4-fold, about a 4.5-fold, about a 5-fold, about a 5.5-fold, about a 6-fold, about a 6.5-fold, about a 7-fold, about a 7.5-fold, about a 8-fold, about a 8.5-fold, or about a 9-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of a control platelet population. In another embodiment, the platelets having a low binding capacity to rFVIIa have about a 10-fold, about a 11-fold, about a 12 fold, about a 13-fold, about a 14-fold, about a 15-fold, about a 16-fold, about a 17-fold, about a 18-fold, about a 19-fold, about a20-fold, about a 21-fold, about a 22-fold, about a 23-fold, about a 24-fold, about a 25-fold, about a 26-fold, about a 27-fold, about a 28-fold, about a 29-fold, about a 30-fold, about a 31-fold, about a 32-fold, about a 33-fold, about a 34-fold, about a 35-fold, about a 36-fold, about a 37-fold, about a 38-fold, about a 39-fold, about a 40-fold, about a 41-fold, about a 42-fold, about a 43-fold, about a 44-fold, about a 45-fold, about a 46-fold, about a 47-fold, about a 48-fold, about a 49-fold, about a 50-fold, about a 51-fold, about a 52-fold, about a 53-fold, about a 54-fold, about a 55-fold, about a 56-fold, about a 57-fold, about a 58-fold, about a 59-fold, about a 60-fold, about a 70-fold, about a 80-fold, about a 90-fold, about a 100-fold, about a 150-fold, about a 200-fold, about a 250-fold, about a 300-fold, about a 350-fold, about a 400-fold, about a 450-fold, or about a 500-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of a control platelet population.
In another embodiment, the platelets having a low binding capacity to rFVIIa have about a 0.1-fold to 0.3-fold, about a 0.2-fold to 0.4-fold, about a 0.3-fold to 0.5-fold, about a 0.4-fold to 0.6-fold, about a 0.5-fold to 0.7-fold, about a 0.6-fold to 0.8-fold, about a 0.7-fold to 0.9-fold, about a 0.8-fold to 1.0-fold, about a 0.9-fold to 1.1-fold, about a 1-fold to 1.5-fold, about a 1.25-fold to 1.75-fold, about a 1.5-fold to 2-fold, about a 1.75-fold to 2.25-fold, about a 2-fold to 2.5-fold, about a 2.25-fold to 2.75-fold, about a 2.5-fold to 3-fold, about a 2.75-fold to 3.25-fold, about a 3-fold to 4-fold, about a about a 3.5-fold to 4.5-fold, about a 4-fold to 5-fold, about a 4.5-fold to 5.5-fold, about a 5-fold to 6-fold, about a 6-fold to 8-fold, about a 8-fold to 10-fold, about a 10-fold to 12-fold, about a 12-fold to 14-fold, about a 14-fold to 16-fold, about a 16-fold to 18-fold, about a 18-fold to 20-fold, about a 20-fold to 25-fold, about a 25-fold to 30-fold, about a 30-fold to 40-fold, about a 40-fold to 50-fold, about a 50-fold to 70-fold, about a 70-fold to 90-fold, about a 90-fold to 100-fold, about a 100-fold to 120-fold, about a 120-fold to 140-fold, about a 140-fold to 160-fold, about a 1-fold to 20-fold, about a 10-fold to 30-fold, about a 20-fold to 40-fold, about a 30-fold to 50-fold, about a 40-fold to 60-fold, about a 50-fold to 80-fold, about a 60-fold to 80-fold, about a 70-fold to 90-fold, about a 80-fold to 100-fold, about a 100-fold to 150-fold, about a 130-fold to 180-fold, or any range in between, higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of a control platelet population.
In another embodiment, the platelets having a low binding capacity to rFVIIa have about a 50%, 75%, 100%, 125%, 150%, 175%, 200%, 300%, 400%, or a 500% higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of a control platelet population.
The invention also provides a method of treating a bleeding disorder in a subject in need thereof. The method comprises administering to the subject a therapeutically effective amount of a platelet population, wherein the platelets in the platelet population demonstrate at least a 15-fold higher rFVIIa relative fluorescence after exposure to 100 nM rFVII. Optionally, the platelet population comprises non-activated platelets demonstrating at least a 25-fold higher rFVIIa relative fluorescence after exposure to 100 nM rFVIIa. Also optionally, the platelet population comprises activated platelets demonstrating at least a 20-fold higher rFVIIa relative fluorescence after exposure to 100 nM rFVIIa, e.g., at least a 30-fold higher rFVIIa relative fluorescence, after exposure to 100 nM rFVIIa. “rFVIIa relative fluorescence” refers to the median fluorescence increase associated with rFVIIa binding to platelets in a sample compared to a fluorescence detected in a buffer control (e.g., a sample of the buffer used to prepare the platelet sample for fluorescence detection). Methods of detecting and quantifying fluorescence associated with rFVIIa binding is described herein and understood in the art. Any suitable exposure time to rFVIIa (e.g., 7, 10, 15, or 20 minute incubation times) is appropriate.
Further, rFVIIa relative fluorescence may be employed to select subjects with enhanced ability to respond to rFVIIa treatment or subjects with a predisposition to low responses to rFVIIa treatment. In this regard, the methods of the invention provide valuable insight to a clinician when preparing therapeutic regimen, as a “high responder” (i.e., a subject having platelets with increased capacity for rFVIIa binding) may require lower doses or fewer administrations of rFVIIa, while a “low responder” (i.e., a subject having platelets with reduced ability to bind rFVIIa) may require higher doses or more administrations of treatment. Similarly, “low responders” may benefit from alternative treatment, such as the alternative treatments described herein.
In one aspect, the invention provides a method of treating a bleeding disorder in a subject in need thereof, the method comprising administering a therapeutically effective amount of rFVIIa to the subject, wherein (a) a sample of platelets derived from the subject was obtained; (b) a non-activated platelet population from the sample was incubated with rFVIIa; and (c) platelets demonstrating at least a 15-fold higher rFVIIa relative fluorescence after exposure to 100 nM rFVIIa were detected in the platelet population. Optionally, non-activated platelets demonstrating at least a 11-fold, at least a 14-fold (e.g., at least a 15.5-fold or 18.7-fold) higher, at least a 20-fold higher, at least a 25-fold higher, at least a 30-fold higher (e.g., at least a 32.8-fold higher), at least a 35-fold higher, at least a 40-fold higher, or at least a 50-fold higher rFVIIa relative fluorescence is detected. Alternatively or in addition, (a) a sample of platelets derived from the subject was obtained; (b) an activated platelet population from the sample was incubated with rFVIIa; and (c) platelets demonstrating at least a 20-fold higher rFVIIa relative fluorescence after exposure to 100 nM rFVIIa were detected in the platelet population. Optionally, activated platelets demonstrating at least a 13-fold higher, at least a 14-fold higher, at least a 20.5-fold higher, at least a 25-fold higher, at least a 30-fold higher (e.g., at least a 34.3-fold higher), at least a 35-fold higher, at least a 40-fold higher, at least a 45-fold higher, at least a 50-fold higher, or at least a 60-fold higher rFVIIa relative fluorescence is detected.
The invention also includes a method of treating a bleeding disorder in a subject in need thereof, the method comprising administering a therapeutically effective amount of an alternative therapy to the subject, wherein a sample of platelets derived from the subject was obtained; a non-activated platelet population from the sample was incubated with rFVIIa; and platelets demonstrating an 8-fold higher rFVIIa relative fluorescence or less after exposure to 100 nM rFVIIa were detected in the platelet population. In this regard, platelets in the sample demonstrate a no more than 8-fold increase in rFVIIa relative fluorescence (i.e., demonstrate a 7-fold, a 6.5-fold, a 6-fold, a 5.5-fold, a 5-fold, a 4.5-fold, a 4-fold, a 3.5-fold, a 2-fold, a 1.5-fold, or less increase). Alternatively or in addition, a sample of platelets derived from the subject was obtained; an activated platelet population from the sample was incubated with rFVIIa; and platelets demonstrating a 9-fold higher rFVIIa relative fluorescence or less, after exposure to 100 nM rFVIIa were detected in the platelet population. Optionally, activated or non-activated platelets demonstrate a 8-fold higher rFVIIa relative fluorescence or less, a 6-fold higher rFVIIa relative fluorescence or less, a 5-fold higher rFVIIa relative fluorescence or less, a 4-fold higher rFVIIa relative fluorescence or less, a 3-fold higher rFVIIa relative fluorescence or less, or a 2-fold higher rFVIIa relative fluorescence or less. Any of the ranges described above with respect to higher or lower rFVIIa binding capacity also apply to rFVIIa relative fluorescence.
The increase in rFVIIa binding upon platelet activation (dual-agonist activation) also is a suitable for selecting subjects for a particular therapeutic regimen. The invention provides a method of treating a bleeding disorder in a subject in need thereof, the method comprising administering a therapeutically effective amount of rFVIIa to a subject having platelets that demonstrate at least a 2.0-fold increase, at least a 3.0-fold increase, or at least a 3.5-fold increase in binding capacity upon dual-agonist activation compared to rFVIIa binding capacity of non-activated platelets from the subject. Optionally, the platelets demonstrate at least a 4-fold increase, at least a 4.5-fold increase, or at least a 5-fold increase in binding capacity upon dual-agonist activation
Also provided is a method of treating a bleeding disorder in a subject in need thereof, the method comprising administering a therapeutically effective amount of an alternative therapy to a subject having platelets that demonstrate a 1.6-fold increase in binding capacity or less or a 1.3-fold increase in binding capacity or less upon dual-agonist activation (e.g., activation with thrombin and convulxin) compared to rFVIIa binding capacity of non-activated platelets from the subject. For example, in various embodiments, the subject has platelets that demonstrate a 1.0-fold increase or less upon dual-agonist activation compared to rFVIIa binding capacity of non-activated platelets from the subject. rFVIIa capacity increase may be determined by calculating the ratio of median fluorescence increase (MFI) of dual-agonist activated platelets versus non-activated platelets from the subject. rFVIIa capacity increase also may be determined by calculating MFI of non-activated platelets, activating the platelets using dual agonists, calculating the MFI of activated platelets, and determining the ratio of the MFI values.
In one aspect, the invention includes a subpopulation of platelets described herein (e.g., a subpopulation of platelets have at least a 4-fold higher binding capacity to rFVIIa as compared to the binding capacity to rFVIIa of other platelets in the platelet population from which the subpopulation was derived). Also included is a platelet population comprising platelets having a higher binding capacity to rFVIIa as compared to the binding capacity to rFVIIa of platelets in a control platelet population. Also provided is a platelet population that demonstrates at least a 3.5-fold increase in binding capacity upon dual-agonist activation compared to rFVIIa binding capacity of non-activated platelets obtained from same the subject, and a platelet population that demonstrates at least a 15-fold higher rFVIIa relative fluorescence after exposure to 100 nM rFVIIa, as described herein. The subpopulation of platelets or the platelet population is optionally in the form of a pharmaceutical composition.
In one embodiment, the pharmaceutical composition is used in a method of treating a bleeding disorder, such as hemophilia (e.g., hemophilia A or hemophilia B) or a non-hemophilia bleeding disorder, in subject. In various aspects, the method comprises administering to a subject a therapeutically effective amount of a platelet population containing comprising the subpopulation of platelets described herein, e.g., a subpopulation of platelets have at least a 4-fold higher binding capacity to rFVIIa as compared to the binding capacity to rFVIIa of other platelets in the platelet population). Optionally, the subpopulation comprises at least 0.5%, at least 1%, at least 3%, at least 4%, at least 5%, at least 6%, at least 7%, at least 8%, at least 9%, at least 10%, at least 11%, at least 12%, at least 13%, at least 14%, at least 15%, at least 16%, at least 17%, at least 18%, at least 19%, at least 20%, at least 21%, at least 22%, at least 23%, at least 24%, at least 25%, at least 26%, at least 27%, at least 28%, at least 29%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95% or 100% of the platelet population administered to the subject. The invention further contemplates the subpopulation of platelets for use in treating a bleeding disorder, or for use in preparing a medicament for treating a bleeding disorder.
The invention also includes a method of treating a bleeding disorder in a subject in need thereof, wherein the method comprises administering to the subject a therapeutically effective amount of a platelet population, wherein the platelets in the platelet population have a higher binding capacity to rFVIIa as compared to the binding capacity to rFVIIa of platelets in a control platelet population. The invention further contemplates the population of platelets for use in treating a bleeding disorder, or for use in preparing a medicament for treating a bleeding disorder.
Hemophilia and non-hemophilia disorders are described above. The subject is, in various embodiments, a mammal, such as a human or a rodent (e.g., mouse or rat), cow, pig, sheep, goat, cat, horse, dog, or other species of animal used as livestock or kept as pets. In one aspect, the subject has been diagnosed with a bleeding disorder, is predisposed to (or is at risk of) developing a bleeding disorder, or is suspected to have a bleeding disorder. In various embodiments, the subject is being treated for a bleeding disorder before being treated according to the methods of the invention. In other embodiments, the subject is not being treated for a bleeding disorder before being treated according to the methods of the invention.
In certain embodiments, the subject is a human and a platelet population or a subpopulation of platelets according to the methods described herein are human cells. The platelets are activated (coated or not coated) or not activated. The platelets may comprise a predetermined percentage of activated or non-activated platelets and/or a predetermined percentage of coated or non-coated (e.g., activated, non-coated) platelets. For instance, the platelet subpopulation or population administered to a patient optionally comprises at least 50%, at least 60%, at least 70%, at least 80%, at least 90% or at least 99% of a desired platelet type. It will be understood that the platelet population or subpopulation administered need not be absolutely homogenous (i.e., 100% of a particular platelet type); less than 100% (e.g., 99%, 98%, or 97% or less) also is contemplated herein.
In some embodiments, a platelet population or a subpopulation of platelets according to the methods described herein can be supplied in the form of a pharmaceutical composition, comprising pharmaceutical carrier (e.g., an isotonic excipient) prepared under sufficiently sterile conditions for human administration and selected on the basis of the chosen route of administration and standard pharmaceutical practice. Techniques and formulations generally can be found in Remmington's Pharmaceutical Sciences, Meade Publishing Co., Easton, Pa. (20th Ed., 2000), the entire disclosure of which is herein incorporated by reference. For general principles in medicinal formulation of platelets, see Sweeney et al., 1995, Quality of Platelet Concentrates, Immunological Investigations, 24(1&2), 353-370; and Stroncek D. F. and Rebulla P., 2007, Platelet Transfusions, The Lancet, 370(9585), 427-438. According to the invention, a pharmaceutically acceptable carrier can comprise any and all solvents, dispersion media, coatings, antibacterial and antifungal agents, isotonic and absorption delaying agents, and the like, compatible with pharmaceutical administration. The use of such media and agents for pharmaceutically active substances is well known in the art. Any conventional media or agent that is compatible with the platelet population or subpopulation of platelets according to the invention can be used. Supplementary active compounds can also be incorporated into the compositions. Lyophilized forms of compositions (or platelet populations or subpopulations) are also included. Compositions of the invention are characterized as being at least sterile and pyrogen-free. The compositions include formulations for human and veterinary use.
Choice of the excipient and any accompanying elements of the composition comprising a platelet population or a subpopulation of platelets according to the methods described herein will be adapted in accordance with the route and device used for administration. Examples of routes of administration include parenteral, e.g., intravenous or intraarterial, administration. Solutions or suspensions used for parenteral application can include one or more of the following components: a sterile diluent such as water for injection, saline solution, fixed oils, polyethylene glycols, glycerine, propylene glycol or other synthetic solvents; antibacterial agents such as benzyl alcohol or methyl parabens; antioxidants such as ascorbic acid or sodium bisulfite; chelating agents such as ethylenediaminetetraacetic acid; and buffers such as acetates, citrates or phosphates and agents for the adjustment of tonicity such as sodium chloride or dextrose. pH can be adjusted with acids or bases, such as hydrochloric acid or sodium hydroxide. The parenteral preparation can be enclosed in ampoules, containers, or blood bags made of glass or plastic.
In some embodiments, a composition comprising a platelet population or a subpopulation of platelets according to the methods described herein can also comprise, or be accompanied with, one or more other ingredients that facilitate the delivery or functional mobilization of the platelet population or a subpopulation of platelets according to the methods described herein. Suitable ingredients include, for example, citrate phosphate dextrose (CPD) solution, plasma solutes, glucose, phosphate based buffering systems, bicarbonate based buffering systems, fatty acids, amino acids, sodium acetate, or other ingredients that support the storage and delivery of a platelet population or a subpopulation of platelets according to the methods described herein. In another embodiment, the composition may comprise autologous blood plasma or blood plasma (for additional information, see Sweeney et al., 1995).
Pharmaceutical compositions suitable for injectable use include sterile aqueous solutions (where water soluble) or dispersions and sterile powders for the extemporaneous preparation of sterile injectable solutions or dispersions. Liquid formulations can comprise one or more physiologically compatible buffers, such as citrate phosphate dextrose solution (see e.g., Sweeney et al., 1995). For intravenous administration, suitable carriers include physiological saline, bacteriostatic water, Cremophor EM™ (BASF, Parsippany, N.J.) or phosphate buffered saline (PBS). In all cases, the composition must be sterile and should be fluid to the extent that easy syringability exists. It must be stable under the conditions of manufacture and storage and must be preserved against the contaminating action of microorganisms such as bacteria and fungi. The carrier can be a solvent or dispersion medium containing, for example, water, ethanol, a pharmaceutically acceptable polyol like glycerol, propylene glycol, liquid polyetheylene glycol, and suitable mixtures thereof. The proper fluidity can be maintained, for example, by the use of a coating such as lecithin, by the maintenance of the required particle size in the case of dispersion and by the use of surfactants. Prevention of the action of microorganisms can be achieved by various antibacterial and antifungal agents, for example, parabens, chlorobutanol, phenol, ascorbic acid, thimerosal, and the like. In many cases, it can be useful to include isotonic agents, for example, sugars, polyalcohols such as mannitol, sorbitol, sodium chloride in the composition. Prolonged absorption of injectable compositions can be brought about by incorporating an agent which delays absorption, for example, aluminum monostearate and gelatin.
Sterile injectable solutions can be prepared by incorporating the platelet population or a subpopulation of platelets in the required amount in an appropriate solvent with one or a combination of ingredients enumerated herein, as required, followed by filtered sterilization. Generally, dispersions are prepared by incorporating a platelet population or a subpopulation of platelets of the invention into a sterile vehicle which contains a basic dispersion medium and the required other ingredients from those enumerated herein.
Examples of diluents and/or carriers and/or other additives that may be used include, but are not limited to, water, glycols, oils, alcohols, aqueous solvents, organic solvents, DMSO, saline solutions, physiological buffer solutions, peptide carriers, starches, sugars, preservatives, antioxidants, coloring agents, pH buffering agents, granulating agents, lubricants, binders, disintegrating agents, emulsifiers, binders, excipients, extenders, glidants, solubilizers, stabilizers, surface active agents, suspending agents, tonicity agents, viscosity-altering agents, carboxymethyl cellulose, crystalline cellulose, glycerin, gum arabic, lactose, magnesium stearate, methyl cellulose, powders, saline, sodium alginate. The combination of diluents and/or carriers and/or other additives used can be varied taking into account the nature of the active agents used (for example the solubility and stability of the active agents), the route of delivery (e.g. oral, parenteral, etc.), whether the agents are to be delivered over an extended period (such as from a controlled-release capsule), whether the agents are to be co-administered with other agents, and various other factors. One of skill in the art will readily be able to formulate the composition for the desired use without undue experimentation.
For parenteral administration (i.e., administration by through a route other than the alimentary canal), a platelet population or subpopulation of platelets of the invention may be combined with a sterile aqueous solution that is isotonic with the blood of the subject. Such a formulation may be prepared by dissolving the active ingredient in water containing physiologically-compatible substances, such as sodium chloride, glycine and the like, and having a buffered pH compatible with physiological conditions, so as to produce an aqueous solution, then rendering the solution sterile. The formulation may be presented in unit or multi-dose containers, such as, but not limited to, containers or blood bags. The formulation may be delivered by injection, infusion, or other means known in the art.
In some embodiments, a platelet population or subpopulation of platelets of the invention is provided in unit dose form such as a single-dose injection or infusion vial.
A platelet population or a subpopulation of platelets according to the invention is administered by any means available for use in conjunction with pharmaceuticals, either as individual therapeutic active ingredients or in a combination of therapeutic active ingredients. In various embodiments, a platelet population or a subpopulation of platelets according to the methods described herein is formulated and administered to reduce the symptoms associated with a bleeding disorder by any means that allow the platelets to exert their effect on the subject in vivo, e.g., administered to any suitable location allowing platelet binding to rFVIIa. In various aspects, a platelet population or a subpopulation of platelets according to the methods described herein is administered systemically. A platelet population or a subpopulation of platelets of the invention may be administered parenterally, e.g., by intravascular, intravenous, or intraarterial delivery. Delivery may be effected by injection, infusion, or catheter delivery. In one embodiment, a platelet population or a subpopulation of platelets of the invention is administered to the subject directly to the vascular system via catheter inserted into a vein of the subject. Methods of administering a composition to a subject are further described in Sweeney et al., 1995 and Stroncek et al., 2007.
Administration of a platelet population or a subpopulation of platelets is not restricted to a single route, but may encompass administration by multiple routes. Multiple administrations (whether by the same route or different routes of administration) may be sequential or concurrent. Other modes of application by multiple routes will be apparent to one of skill in the art.
In certain embodiments, a platelet population or a subpopulation of platelets according to the methods described herein can be administered and dosed in accordance with good medical practice, taking into account the clinical condition of the individual patient, the site and method of administration, scheduling of administration, patient age, sex, body weight and other factors known to one of skill in the art, such as, but not limited to, a medical practitioner. A platelet population or a subpopulation of platelets according to the methods described herein may be administered to a subject in a therapeutically effective amount to treat a bleeding disorder. A “therapeutically effective amount,” for purposes herein, is thus determined by such considerations as are known in the art. The amount can be effective to achieve improvement, including, but not limited to, improved bleeding time, improved clotting time, improved prothrombin time, improved partial thromboplastin time, improved activated clotting time, or improvement or elimination of symptoms and other indicators as are selected as appropriate measures by those skilled in the art. For additional information, see e.g., The Absite Review by Steven M. Fiser, Lippincott Williams and Wilkins 2004.
A therapeutically effective amount of a platelet population or a subpopulation of platelets that treats a bleeding disorder can depend upon a number of factors known to those of ordinary skill in the art. The dose(s) of a platelet population or a subpopulation of platelets according to the methods described herein can vary, for example, depending upon the identity, size, and condition of the subject or sample being treated, further depending upon the route by which a platelet population or a subpopulation of platelets according to the methods described herein, is to be administered, if applicable, and the effect which the practitioner desires the platelet population or a subpopulation of platelets according to the invention to have upon the target of interest. These amounts can be readily determined by one of skill in the art. These amounts include, for example, number of platelets per kilogram (kg) of subject weight, such as about 1×109 cells/10 kg, about 1×1010 cells/10 kg, about 1×1011 cells/10 kg, about 1×1012 cells/10 kg, or between about 1×109 cells/10 kg to 1×1012 cells/10 kg, 1×109 cells/10 kg to 1×1010 cells/10 kg, 1×1010 cells/10 kg to 1×1011 cells/10 kg, or to 1×1011 cells/10 kg to 1×1012 cells/10 kg, or any range in between. These amounts also include a unit dose of platelets, for example, at least 1×109 cells, 1×1010 cells, 1×1011 cells, 1×1012 cells, or 1×1013 cells, or more. For additional information, see Stroncek et al., 2007. Any of the therapeutic applications described herein can be applied to any subject in need of such therapy, including, for example, a mammal, such as a human.
Appropriate dosing regimens can also be determined by one of skill in the art without undue experimentation in order to determine, for example, whether to administer the agent in one single dose or in multiple doses, and in the case of multiple doses, to determine an effective interval between doses. For example, in one aspect, a platelet population or a subpopulation of platelets described herein is administered to the subject once (e.g., as a single injection or infusion). Alternatively, a platelet population or a subpopulation of platelets according to the methods described herein is administered once or twice daily to a subject in need thereof for a period of from, e.g., about two to about twenty-eight days, or from about seven to about ten days. A platelet population or a subpopulation of platelets according to the methods described herein can also be administered once or twice daily to a subject over the course of a year, wherein the once or twice daily administration occurs 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 times per year.
In certain embodiments, a platelet population or a subpopulation of platelets according to the methods described herein is stored for later injection/infusion. In some embodiments, a platelet population or a subpopulation of platelets according to the methods described herein can be stored for up to 5 days, up to one week, or up to two weeks. For additional information, see Stroncek et al., 2007.
Therapy dose and duration will depend on a variety of factors, such as the disease type, patient age, therapeutic index of the drugs, patient weight, and tolerance of toxicity. Initial dose levels will be selected based on their ability to achieve ambient concentrations shown to be effective in in vivo models, and in clinical trials. The skilled clinician using standard pharmacological approaches can determine the dose of a particular therapeutic and duration of therapy for a particular patient in view of the above stated factors. The response to treatment can be monitored by analysis of coagulation measures, and one of skill in the art, such as a clinician, will adjust the dose and duration of therapy based on the response to treatment revealed by these measurements.
In various embodiments, a platelet population or a subpopulation of platelets according to the methods described herein are administered alone (e.g., as a single agent) or in combination with one or more other agents (e.g., therapeutic agents). Suitable additional agents include, but are not limited to, cells, tissue, tissue fragments, biologically active or inert compounds, and small molecules.
In various embodiments, a platelet population or subpopulation of platelets of the invention are used in combination with other agents that are used for the treatment or prevention of a bleeding disorders, such as clotting factors (e.g., Factor VIIa (rFVIIa), Factor VIII (FVIII), and Factor IX (FIX)). Examples of agents suitable for use in connection with the platelet population or subpopulation include, but are not limited to, recombinant Factor VIIa, such as Novoseven®, FEIBA, BeneFix® (recombinant Factor IX), Kogenate® FS (recombinant Factor VIII), Recombinate (recombinant Factor VIII), Advate® (recombinant Factor VIII), Helixate® FS (recombinant Factor VIII), Koāte®-DVI (recombinant Factor VIII), Stimate® (desmopressin acetate), DDAVP® (desmopressin acetate), Bebulin (Factor IX Complex), Hemofil M® (human factor VIII), cryoprecipitated antihaemophilic factor (AHF), fresh frozen plasma (FFP), recombinant porcine FVIII, recombinant FV variants, recombinant FVIIa variants, recombinant FXa variants, FXIII, prothrombin, a mix of coagulation factors, antibodies mimicking FVIII, peptides mimicking FVIII, compounds mimicking FVIII, peptide inhibitors of TFPI, antibody inhibitors of TFPI, compounds inhibiting TFPI, compounds inhibiting anti-coagulant proteins, agents resulting in reduced expression of anti-coagulant proteins (e.g., compounds that reduce expression or antisense oligonucleotides that reduce expression of an anti-coagulant protein), and any therapy for treating a bleeding disorder that does not comprise rFVIIa as a single agent, as determined by a person of skill in the art.
In various embodiments, a platelet population or subpopulation of platelets of the invention are used in combination with agents that are not used for the treatment or prevention of bleeding disorders, such as (but not limited to) additives intended to, for example, enhance the delivery, efficacy, tolerability, or function of the platelet population or a subpopulation of platelets.
A platelet population or subpopulation of platelets of the invention and other agents may be administered to the subject at the same time or at different times. For example, in one embodiment, a platelet population or subpopulation of platelets of the invention is delivered to a subject as part of the same pharmaceutical composition or formulation containing one or more additional agents. Alternatively, one or more other agents are administered to the subject in one or more separate compositions or formulations. A platelet population or subpopulation of platelets of the invention and one or more other agents are optionally administered within minutes, hours, days, weeks, or months of each other, for example as part of the overall treatment regimen of a subject. A platelet population or subpopulation of platelets of the invention is optionally administered prior to the administration of other agents. In various embodiments, a platelet population or subpopulation of platelets of the invention is administered subsequent to the administration of other agents.
A platelet population or subpopulation of platelets of the invention may also be used in combination with surgical or other interventional treatment regimens used for the treatment of bleeding disorders. In some embodiments, a platelet population or subpopulation of platelets of the invention is used as an adjuvant therapy. In other embodiments, a platelet population or subpopulation of platelets of the invention is used in combination with an adjuvant therapy.
In another aspect, the invention provides a method of determining whether a subject is a candidate for treatment with rFVIIa, the method comprising (a) obtaining a sample of platelets derived from the subject; (b) incubating a platelet population from the sample with rFVIIa; and (c) detecting whether the platelet population contains a subpopulation of platelets having at least a 4-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of the other platelets in the platelet population. In one aspect, this candidate is a candidate for treatment with rFVIIa if the subject does not have an unacceptable risk of thrombosis, and if the platelet population contains a subpopulation of platelets having at least a 4-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of the other platelets in the platelet population. In various embodiments, the candidate is a candidate for treatment if the subpopulation represents at least 2%, at least 3%, at least 4%, at least 5%, at least 10%, at least 15%, or at least 20% of the platelet population. In another aspect, the subject is a candidate for treatment with rFVIIa if the subject has an unacceptable risk of thrombosis, and if the platelet population does not contain a subpopulation of platelets having at least a 4-fold higher binding capacity to rFVIIa, as compared to the binding capacity to rFVIIa of the other platelets in the platelet population. In various embodiments, the platelet population sampled contains less than 5%, less than 3%, less than 2%, or less than 1% of the subpopulation. Methods of characterizing FVIIa binding, features of the platelets of the platelet population and subpopulation, composition of the platelet population and subpopulation (e.g., percentage of platelets with high binding capacity), subjects, biological samples, and bleeding disorders are described herein and applicable to the method.
This example is provided below to facilitate a more complete understanding of the present invention. However, the scope of the invention is not limited to specific embodiments disclosed in this example, which are for purposes of illustration only.
The variation of the rFVIIa binding capacity of platelets in platelet concentrates from 21 healthy donors, and the occurrence and frequency of a platelet subpopulation capable of binding high amounts of rFVIIa, are described herein.
Platelets are identified by staining for CD61 and P-selectin (CD62P) and forward/side scatter gating to discriminate their activation status. Coated platelets can be identified by using a fluorochrome conjugated anti-fibrinogen antibody. rFVIIa bound to activated or non-activated platelets is quantified using a DyLight488-labeled anti human FVIIa antibody. Fresh platelet concentrates are adjusted to 40,000 platelets per μl in 20 mM HEPES and 150 mM NaCl containing buffer adjusted to pH7.35. Platelets were diluted with 9 volumes buffer containing 5.5 mM CaCl2, 0.11 μg/mL convulxin (a collagen receptor GPVI agonist) and 5.5 nM thrombin, if activation was required, and incubated with rFVIIa (BAX817 or Novoseven) at final concentrations from 50 to 2000 nM for 7-15 min at 37° C. and 300 rpm. Then, platelets were fixed with 3.8% final concentration of paraformaldehyde contained in the same buffer and 5 mM CaCl2. Platelets were filtered through a 50 μm mesh filter and blocked for 10 min at room temperature by adding 5% fetal bovine serum. Then, platelets are centrifuged for 10 min at 4° C. and 700 g. For staining of rFVIIa bound to the platelet surface, a rabbit anti human FVIIa polyclonal Dylight 488 antibody conjugate (Affinity BioReagents order #PA1-100250) was used at a final concentration of 20 μg/mL. After 15 min incubation at room temperature in the dark, platelets are counterstained by adding mouse monoclonal antibodies against CD61 (BD order #22458; conjugated to PerCP, 1.2 μg/ml final concentration) and CD62P (BD order #01732; P-selectin, conjugated to PE, final dilution 1:5) and incubated for 15 min at room temperature in the dark. Fibrinogen can be co-stained using a Dylight633 conjugated sheep anti-human fibrinogen antibody (Affinity Biologicals order #SAFG-AP; at 10 μg/mL). Then, wash buffer is added (same buffer w/o FBS), mixed and centrifuged for 10 min at 4° C. and 700 g. Samples are resuspended for FACS analysis. Controls include platelets without rFVIIa, and a mouse IgG1 isotype control conjugated to PerCP (BD order #) at 1.2 μg/mL final concentration, and samples stained with each antibody alone for proper compensation of fluorescence spillover. Median fluorescence intensities of rFVIIa bound to all platelets and to sub-populations varying in rFVIIa binding were determined by flow cytometry. KD values were calculated using SigmaPlot v12.0.
FACS raw data typical for one experiment are shown in
The CD61 signal versus the isotype control for gating of platelets is shown in
Activated and non activated platelets as depicted in
Dose Dependent Binding of rFVIIa to Platelets
In
Detection of a rFVIIa High Binding Subpopulation
An additional, strongly positive FVII—fluorescent population was detected, which is shifting to the left closer to the major peak with longer incubation times (7, 10, 15 min) (mean and median fluorescence becomes lower over time). The percentage of the high FVIIa binding and the major platelet population stayed equal. Two NovoSeven lots were tested and show similar behavior.
Histogram overlay of the FVII DyLight488 staining for different samples as indicated. Population is gated by forward scatter versus side scatter and CD61 (
In
In
In
Dot plot of FVII versus CD62 of Novoseven lot#1 for different platelet samples as indicated. Platelets were activated and incubated with Novoseven for 7 minutes (top), 10 minutes (middle), or 15 minutes (bottom) (
Dot plot of FVII versus CD62 of Novoseven lot#2 for different platelet samples as indicated. Platelets were activated and incubated with Novoseven for 7 minutes (top), 10 minutes (middle), or 15 minutes (bottom) (
Detection of High Donor Variation in rFVIIa Platelet Binding, and Characterization of Donors Regarding the High Binding Subpopulation
Using FACS technology, binding of rFVIIa to platelet concentrates of 21 healthy donors was quantified, based on the assumption that the amount of rFVIIa bound to per cell correlates with the measured fluorescence intensity. In Tables 2 (non-activated) and 3 (double-activated platelets), all donors are listed with protocol addresses, KD values if calculable, relative median fluorescence intensities of the rFVIIa signals of all platelets compared to the controls without rFVIIa, and of frequencies and relative median fluorescence intensities of high binding populations compared to the major rFVIIa binding population. rFVIIa bound concentration dependently to non-activated and dual agonist activated platelets. On activated and non-activated platelets, binding was saturated at rFVIIa concentrations between 200 and 1200 nM. Median fluorescence intensity increase at 100 nM rFVIIa ranged from 4- to 33-fold for non-activated (mean±standard deviation: 14±7.5-fold) and from 5- to 37-fold for activated platelets (mean±standard deviation: 15±9.5-fold) compared with controls without rFVIIa. When assessing the total platelet population, binding constants for activated platelets ranged from 29 to 1025 nM (mean±standard deviation 392±355 nM; n=6), and from 56 to 357 nM (mean±standard deviation 184±88; n=10) for non-activated platelets.
A platelet sub-population consisting of at least 2% was detected in 7 of 21 non-activated platelet donor concentrates, and in 15 of 21 after dual activation. In one donor, this population was visible only within resting platelets, in 9 donors only within activated platelets, and in 6 donors within resting and activated platelets. Up to 24% of total platelets were characterized by high capacity of rFVIIa binding in platelet concentrates from donors positive for this sub-population.
Regarding all donors described, this subpopulation bound on average 32-fold more rFVIIa than the main platelet population when non-activated, and on average 6-fold more within activated platelets. The rFVIIa high binding capacity subpopulation formation did not correlate with platelet activation or “coated” platelet formation, since all dual agonist activated platelets had similar distribution of CD62P and fibrinogen expression following activation.
A substantial inter-individual variation in binding of rFVIIa to resting and activated platelets was observed among a group of 21 donors. In some donor platelet concentrates, sub-populations of platelets with a >10-fold increase in rFVIIa binding, consisting of up to >20% of total platelets after activation, were identified.
This finding supports prediction of therapy outcomes or thrombogenic risks with rFVIIa or other bypassing therapies when studying a patient's platelet population, but also serves as means to improve hemophilia inhibitor bypassing therapy e.g. by recruiting platelet donors possessing the ability to bind high amounts of rFVIIa and isolating their platelets for transfusion. The invention solves the problem of a lack of understanding about this platelet population which is needed to carry out successful hemophilia therapy, off-label use of rFVIIa, or gene therapy when targeting platelets in an effort to treat bleeding disorders. Prior to this invention, there was no explanation why platelets bind more or less rFVIIa, but with this invention including functional and phenotypic characterization and identification of correlating factors, one induce/suppress high binding of rFVIIa to platelets in a patient.
The methods described above were employed to characterize binding of rFVIIa to platelet concentrates of additional healthy donors and using different lots of rFVIIa. Analysis of 19 non-activated platelet samples resulted in a mean apparent KD (calculated from ligand binding curves) of 276 nM (±200 SD) for rFVIIa with a range of 56-897 nM. Analysis of 18 dual-agonist activated platelet samples resulted in a mean apparent KD of 312 nM (±194 SD) for rFVIIa with a range of 36-632 nM. A statistical overview of studies of 37 donors is provided in
The distribution of a rFVIIa high-binding subpopulation among activated vs. non-activated platelets also was determined. Platelet samples were exposed to 100 nM or 50-4000 nM rFVIIa. All donors were classified based on the existence of a high rFVIIa binding subpopulation of at least 2% of all platelets and further subdivided based on the existence of a high rFVIIa binding population present in activated only, non-activated platelets only, or both. Representative results are provided in Table 5:
Boxplot diagrams illustrating the distribution of overall capacity of non-stimulated and dual-agonist activated platelets to bind rFVIIa upon treatment with 100 nM rFVIIa are set forth in
Activated platelets that demonstrated high rFVIIa binding was not limited to coated platelets; the subpopulation of high rFVIIa binding, activated platelets also included non-coated platelets.
While this invention has been described with an emphasis upon various embodiments, it will be obvious to those of ordinary skill in the art that variations of the methods may be used and that it is intended that the invention may be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications encompassed within the spirit and scope of the invention as defined by the following claims.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2014/028865 | 3/14/2014 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 61799875 | Mar 2013 | US |
