IE66266B1 - Method and therapeutic compositions for the treatment of bleeding disorders - Google Patents

Description

This invention relates to the treatment of bleeding disorders. In particular, this invention relates to the use of tissue factor protein to effect haemostasis in certain clinical conditions and particularly in animals lacking certain coagulation proteins. Factor VIII and factor IX deficiencies are two examples.

Bleeding is on® of the most serious and significant manifestations of disease. It may oecur from a local site or may be generalized. Bleeding associated with a local lesion may be superimposed on either a normal or a defective haemostatic mechanism. Normal haemostasis comprises mechanisms operative immediately following an injury and those acting over a longer period. Primary haemostasis consists principally of two components: vasoconstriction and platelet plug formation. The maintenance mechanism consists of the fibrin elot produced by the coagulation system. Platelet plug formation is especially important in capillary haemostasis, while vasoconstriction and -2fibrin clot formation is more important in larger vessel haemostasis. In the microcirculation haemostasis consists of asoconstriction and platelet plug formation. Platelet plug formation may he divided into several stages: adhesion of platelets to subendothelial surfaces exposed by trauma; platelet activation release reaction; platelet aggregation, which results in the sequestration of additional platelets at the site, and the binding of fibrinogen and the coagulation proteins to the platelet surface which includes thrombin formation; and, fusion which is the coalescence of fibrin and fused platelets to form a stable haemostatic plug.

Blood coagulation performs two functions; the production of thrombin which induces platelet aggregation and the formation of fibrin which renders the platelet plug stable. A number of discrete proenzymes and procofactors, referred to as "coagulation factors, participate in the coagulation process. The process consists of several stages and ends with fibrin formation. Fibrinogen is converted to fibrin by the action of thrombin. Thrombin is formed by the proteolytic cleavage of a proenzyme, prothrombin. This proteolysis is effected by activated factor X (referred to as factor Xa) which binds to th® surface of activated platelets and in the presence of Va and ionic calcium cleaves prothrombin.

Activation of faetor X may occur by either of two separate pathways, the extrinsic or the Intrinsic (Figure 1). The intrinsic cascade consists of a series of reactions wherein a protein precursor is cleaved to form an active protease. At each step, the newly formed protease will catalyze the activation of the precursor protease at the subsequent step of the cascade. A deficiency of any of the proteins in the pathway blocks the activation process at that step, thereby preventing clot formation and typically gives rise to a tendency to hemorrhage. Deficiencies of faetor VIII or LC8x267.mhg -3factor XX, for example, cause the severe bleeding syndromes haemophilia A and B, respectively. Xn the extrinsic pathway of blood coagulation, tissue factor, also referred to as tissue thromboplastin, is released from damaged cells and activates factor X in the presence of factor VII and calcium. Although activation of factor X was originally believed to be the only reaction catalysed by tissue factor and factor VII, it is now known that an amplification loop exists between factor X, factor VII, and factor IX (Osterud, 3., and S.I. Rapaport, Proc. Natl. Acad. Sci. USA 24:5260-5264, 1977; Zur, M. et &1., Blood 12: 198, 1978). Each of the serine proteases In this scheme Is capable of converting by proteolysis the other two into the activated form, thereby amplifying the signal at this stage in the coagulation process (Figure 2). It is now believed that the extrinsic pathway may In fact he the major physiological pathway of normal blood coagulation (Haemostasis 13:150-155 1983). Since tissue factor is not normally found in tha blood, the system doss not continuously clot; the trigger for coagulation would therefore be the release of tissue factor from damaged tissue.

Tissue factor is an integral membrane glycoprotein which, as discussed above, can trigger blood coagulation via the extrinsic pathway. Bach, R. et al., J. Biol Chem. 256(16). 8324-8331 (1981). Tissue factor consists of a protein component (previously referred to as tissue factor apoprotein-III) and a phospholipid. Osterud, 3. and Rspaport, S.I., PNAS 74. 5260-5264 (1977). The complex has been found on the membranes of monocytes and different cells of the blood vessel wall. Osterud, B., Scand. J. Haematol. 32., 337-345 (1984). Tissue factor from various organs and species has been reported to have a relative molecular mass of 42,000 to 53,000. Human tissue thromboplastin has been described as consisting of a tissue factor protein inserted into phospholipid bilayer in an optimal ratio of tissue factor protein: phospholipid oi approximately 1:80. Lyberg, T. and Prydz, H., Nouv. Rev. Fr.

LC8x267.mhg -4Hematol 25(5), 291-293 (1983). Purification of tissue factor has been reported from various tissues such as,: human brain (Guha, A. et al. PNAS 83, 299-302 [1986] and Broze,G.H. et al., J.Biol.Chem, 260(201, 10917-10920 [1985]); bovine brain (Bach, R. et al., J. Biol. Chem. 256, 8324-8331 [1981]); human placenta (Bom, V.J.J. gt al. . Thrombosis Res. 42:535-643 [1986]; and, Andoh, K. et al. . Thrombosis Res. 43:275-286 [1986]); ovS.ne brain (Carlsen, E. et al., Thromb. Haemostas. 48[3], 315-319 [1982]); and, lung (Gias, P. and Astrup, T. , Am. J. Physiol. 219. 1140-1146 [1970]. It has been shown that bovine and human tissue thromboplastin are identical in sise and function. Sea for example Broze, G.H. et al. , J. Biol. Chem. 260(20) 10917-10920 (1985). It Is widely accepted that while there are differences in structure of tissue factor protein between species there are no functional differences as measured by in vitro coagulation assays. Guha et al. supra. Furthermore, tissue factor isolated from various tissues of an animal, e.g. dog brain, lung, arteries and vein was similar in certain respects such as, extinction coefficient, content of nitrogen and phosphorous and optimum phospholipid to lipid ratio but differed slightly in molecular size, amino acid content, reactivity with antibody and plasma half life. Gonmori, H. and Takeda, Y., J. Physiol. 229(3). 518-626 (1975). All of the tissue factors from the various dog organs showed clotting activity in the presence of lipid. Id. It is widely accepted that in order to demonstrate biological activity, tissue factor must be associated with phospholipids. Pitlick, F.A., and Nemerson, Y. , Biochemistry 9, 5105-5111 (1970) and Bech,R. et al. supra, at 8324. It has been shown that the removal of the phospholipid component of tissue factor, for example by use of a phospholipase, results in a loss of Its biological activity. Nemerson, Y., J.C.I. 47, 72-80 (1968). Relipidation can restore in vitro tissue factor activity. Pitlick, F.A. and Nemerson, Y. Biochemistry 9, 5105-5113 (1970) and Freyssinet, J.H. et al., Thrombosis and Haemostasis 55, 112-118 [1986]. 1X38x267. mhg -5Infusion of tissue factor has long been believed to compromise normal haemostasis. In 1834 the French physiologist de Blainville first established that tissue factor contributed directly to blood coagulation, de Blainville, H. Gazette Hedicale Paris, Series 2. 524 (1834). de Blainville also observed that intravenous infusion of a brain tissue suspension caused immediate death which he observed was correlated with a hypercoagulative state giving rise to extensively disseminated blood clots found on autopsy. It is now wall accepted that Intravenous infusion of tissue thromboplastin induces Intravascular coagulation and may cause death in various animals. (Dogs: Lewis, J. and Szeto I.F., J. Lab. Clin. Med. 60, 261-273 (1962); rabbits: Redder, G. et al., Thromb. Diath. Haemorrh. 27. 365-37S (1972); rats: Giercksky, K.E. et al., Scand. J. Haematol. 17. 305-311 (1976); and, sheep: CarIsen,a. at al., Thromb. Haemostas. 48, 315-319 [1982]).

In addition to intravascular coagulation or a hypercoagulative state resulting from the exogenous administration of tissue factor, it has been suggested that the intravascular release of tissue thromboplastin may initiate disseminated intravascular coagulation (DIG). Prentice, C.R., Clin. Haematol. 14(2). 413-442 (1985). DIG may arise in various conditions such as shock, septicaemia, cardiac arrest, extensive trauma, bites of poisonous snakes, acute liver disease, major surgery, bums, septic abortion, heat stroke, disseminated malignancy, pancreatic and ovarian carcinoma, promyalocytic leukemia, myocardial Infarction, neoplasms, systemic lupus erythematosus, renal disease and eclampsia. Present treatment of DIG includes transfusion of blood and fresh frozen plasma; infusion of heparin; and removal of foraed thrombi. The foregoing clinical syndromes suggest that endogenous release of tissue factor can result in severe clinical complications. Andoh, K. et al., Thromb. Res. 4J,, 275-286 (1986). Efforts were made to overcome the thrombotic exsect ox tissue thromboplastin using the enzyme thromboplastinase. Gollub, 5. et LC8x267.mhg -δal. , Thromb. Diath. Haemorh. 7, 470-479 (1962). Thromboplastinase is a phospholipase and would presumably cleave the phospholipid portion of tissue factor. Id.

Congenital disorders of coagulation characteristically involve a single coagulation protein. Haemophilia is a bleeding disorder due to inherited deficiency of a coagulation factor, e.g. the procoagulant activity of factor VIII. The basis for therapy of bleeding episodes is transfusion of material containing the missing coagulation protein, e.g. Infusion of factor νϊ II procoagulant activity which temporarily corrects the specific defect of haemophilia A.

Von willabrand’s disease is another bleeding disorder characterised by a prolonged bleeding time in association with an abnormality or deficiency In the von Willebrand protein. Treatment is by Infusion of normal plasma or by a composition rich in von Willebrand protein. Congenital deficiencies of each of the other coagulation factors occur and may be associated with a haemorrhagic tendency. The present therapies for the deficiencies are: factor IX deficiency Is treated using concentrates containing factor IX ; infusions of plasma are given for & factor XI deficiency; and plasma Infusion Is given for a factor XIII deficiency.

Acquired coagulation disorders arise in individuals without previous history of bleeding as a result of a disease process. Inhibitors to blood coagulation factors may occur in multitransfused individuals. Acquired coagulation factor deficiencies with unknown etiology also give rise to haemostatic problems. DIG describes a profound breakdown of the haemostasis mechanism.

An object of the present invention is to provide & coagulation Inducing therapeutic composition for various chronic LC8x267.mhg -7bleeding disorders, characterised by a tendency coward hemorrhage, both inherited and acquired. Examples of such chronic bleeding disorders are deficiencies of factors VIII, IX, or XI. Examples of acquired disorders include: acquired inhibitors to blood coagulation factors e.g. factor VIII, von Willebrand factor, factors IX, V, XI, XII and XIII; haemostatic disorder as a consequence of liver disease which includes decreased synthesis of coagulation factors and DIC; bleeding tendency associated with acute and chronic renal disease which includes coagulation factor deficiencies and DIC; haemostasis after trauma or surgery; patients with disseminated malignancy which manifests in DIC with increases in factors VIII, von Willebrand factor and fibrinogen; and haemostasis during cardiopulmonary surgery and massive blood transfusion.

A further object of this invention is to provide a coagulation problems in disorders. inducing therapeutic composition for acute bleeding normal patients and in those with chronic bleeding Yet another object of this invention is to provide an anticoagulant therapeutic, that is an antagonist co tissue factor protein, to neutralise the thrombotic effects of endogenous release of tissue thromboplastin which may result in a hypercoagulative state. Particularly, such an anticoagulant, chat is an antagonist to tissue factor protein, would neutralise che hypercoagulanc effects of endogenously released tissue thromboplastin by inactivating tissue factor protein. Such a tissue factor protein antagonist can be an antibody or other protein that specifically inactivates the protein component. -8Summarv of the Invention This invention ie based in part «η the novel and unexpected observation that infusion of tissue factor protein Int® rabbits lacking coagulation factors not only corrected haemostatic deficiency bat did not induce disseminated intravascular coagulation or result in other adverse side effects. Tissue factor protein is the protein portion of tissue factor lacking th© naturally occurring phospholipid, which «as previously referred to as tissue factor apoprotein III and previously believed to be inactive. Tissue factor protein «as for rise first tine found to correct the bleeding diathesis„ i.e. a tendency ward hemorrhage, associated with factor VIII deficiency in vivo. Furthermore, infusion of tissue factor protein would fee expected to be ineffective ia light of the papers which describe tissue factor as having an absolute requirement for phospholipid. The efficacy and lack of toxicity observed is in contrast to tbs results race would have expected from the work of de Blalaville and subsequent researchers over the past one hundred and fifty-two years.

Accordingly, in one aspect the Invention is directed to administration of a pharmaceutical composition comprising tissue factor protein as a coagulant in patients with bleeding disorders. In another aspect the Invention Is directed to a method of treatment of chronic bleeding disorders. Yet another aspect is a method of treatment of acute bleeding incidents in patients having chronic bleeding disorders. A further aspect of this invention Is directed to an anticoagulant to neutralize the coagulant effects of endogenously released tissue thromboplastin by inactivating tissue factor protein.

Brief iStescylption.jflif· the Brewings Figure 1. Diagram showing activation of blood coagulation via intrinsic pathway.

LG8x2S7.mhg -9Figure 2. Diagram showing amplification of coagulation signal via extrinsic pathway.

Figure 3. Cuticle bleeding times (CBT) in animals receiving tissue factor protein. Arrows denote dose of tissue factorprotein in U/kg. Pre refers to CBT prior to any injection.

Detailed Description As used herein, tissue factor protein refers to a protein capable of correcting various bleeding disorders, particularly those associated with deficiencies in coagulation factors. Tissue factor protein is distinct from tissue factor or tissue thromboplastin in that it lacks the naturally occurring lipid portion of the molecule. Tissue factor protein also Includes tissue faster protein .associated with phospholipid which lipid is distinct fro» the naturally occurring lipid associated with tissue thromboplastin and which displays coagulation-inducing capability without the concomitant toxicity observed with the lipidated protein. Infusion ©f tissue factor protein,, as defined herein, does not result in disseminated intravascular coagulation. The capacity of tissue factor protein to correct various bleeding disorders is readily determined using various in vivo bleeding models e.g. initiation of coagulation in hemophilic dogs using cuticle bleeding time determination (Giles, A.R. et al. P Blood 60:727-730 [1982]).

Tha term tissue factor protein antagonists as used herein refers to substances which may function in two ways. First, tissue factor protein antagonists will bind to tissue factor protein with sufficient affinity and specificity to neutralize tissue factor protein such that It cannot bind to factor Vil or wll,a nor effect the proteolysis of factors IX or X when in complex with factor VII or VIIS. Alternatively, tissue factor protein antagonists will LC8x267.mhg v. -10inactivate tissue factor protein or the tissue factor/factor VIIa complex by cleavage, e.g. a specific protease. Antagonists are useful, either alone or together, in the therapy of various coagulation disorders as evidenced by altered plasma fibrinogen levels as described herein e.g. DIC occurring during severe infections and septicemias, after surgery or trauma, instead os or in combination with other anticoagulants such as heparin.

An example of an antagonist which will neutralise tissue factor protein is a neutralising antibody to tissue factor protein. Tissue factor protein neutralising antibodies are readily raised in animals such as rabbits or mice by immunisation with tissue factor protein in Freund’s adjuvant followed by boosters as required. Immunised mice are particularly useful for providing sources of 3 eells for the manufacture of hybridomas, which in turn are cultured to produce large quantities of inexpensive anti-tissue factor protein monoclonal antibodies. Such tissue factor protein monoclonal antibodies have been prepared by Carson, S.D. et al. , Blood £6(1), 152-156 (1985).

Tissue factor is released from damaged cells and activates factors IX and X in the presence of factor VII or VIIa and calcium. (See Figure 2) Ths activation of factor X by the extrinsic pathway of coagulation has an absolute requirement for tissue factor. Silverberg, S.A. „ et al., J. Biol. Chem. 252. 8481-8488 (1977). Until the discovery of this invention, it was thought that the lipid component of tissue factor was essential for optimal tissue factor activity in the catalysis of factor X or factor IX by factor VII or V1XS. This invention encompasses the treatment of various acute and chronic bleeding disorders by bypassing those deficiencies through the administration of tissue factor protein. More particularly this invention is applicable to those bleeding disorders arising In animals deficient in various coagulation factors.

LC8x267.mhg -11Tissue thromboplastin or tissue factor consists of a glycoprotein component (previously referred to as tissue factor apoprotein III) which has been purified to apparent homogeneity (Bjorklld, E. et al., Biochem. Biophys. Res. Commun. 55. 969-976 [1973]) and a phospholipid fraction. Numerous reports have described the purification of tissue factor from many types of tissue such as brain, lung and placenta. Sheep, cow, rabbit, dog and human have been a source of tissue factor. The first step in the chemical purification has been to dissociate tissue factor from its native lipid using, for example, extraction with organic solvents. Examples of such organic solvents include pyridine, heptane-butanol mixture or ethanol. Tissue factor protein has been purified by chemical means. Examples of such chemical means are: treatment with detergents, such as deoxycholate or Triton X-100; gel filtration and preparative polyacrylamide-gel electrophoresis in the presence of sodium dodecyl sulphate; concanavalin A bound to a Sepharose column; and, affinity columns using antibodies to the tissue factor protein or selective adsorption to factor VII. Included within the scope of tissue factor protein is tissue factor protein from recombinant or synthetic sources. Also included are dimers of tissue factor protein and tissue factor protein variants having amino acid substitutions and/or deletions and/or additions, organic and inorganic salts and covalently modified derivatives of tissue factor protein. Tissue factor protein produced by recombinant means may include a naturally occurring pro-form as well as a prepro-form of tissue factor protein.

For use in this invention tissue factor protein or tissue factor protein antagonists may be formulated into an injectable preparation. Parenteral formulations are suitable for use in the Invention, preferably for intravenous administration. These formulations contain therapeutically effective amounts of tissue factor protein, are either sterile liquid solutions, liquid LC8x267.sihg -12suspensions or lyophilized versions and optionally contain stabilisers or excipients. Typically, lyophilized compositions are reconstituted with suitable diluents, e.g. sterile water for injection, sterile saline and the like where the biological activity is sufficient to induce haemostatic coagulation as observed in a rabbit infusion study.

Alternatively, for use in this Invention tissue factor protein can be formulated into a preparation for absorption through the gastrointestinal tract. Such a preparation is suitable for use in the Invention for oral administration. Such oral preparations contain therapeutically effective amounts of tissue factor protein, a lipophilic vehicle and a gastrointestinal tract absorption enhancing agent. Suitable lipophilic vehicles include mineral oil, triglycerides, esterified glycols, polyglycols with hydrophobic alkyl side chains, and sterols. Examples of an absorption enhancer include hydroxyaryl or hydroxyaralkyl acids or their salts, esters or amides. Other compounds with similar properties Include salicylic acid derivatives, amines of 1,3 dicarbonyl compounds and enamino acids, and their salts, amides and esters.

Tissue factor protein may be administered by Injection intravascularly or by oral administration at a dosage sufficient to correct a bleeding disorder, for example, replacement therapy in the face of a factor VIII deficiency. Tissue factor protein may be administered at a dosage sufficient to correct an acute bleeding incident in the face of a coagulation factor deficiency, TOberapeutic dosage of tissue factor protein Is ia the range of about from 10 ϋ/kg to 30© U/kg. A preferred therapeutic dosage of tissue factor pretela Is In the range of absst 50 Π/kg to 250 Π/kg. A most preferred therapeutic dosage of tissue factor protein is in the range of about 75 O/kg to 200 U/fcg. In the absence of an international standard of tissue factor activity we have established a tissue factor standard. A unit of tissue factor LC8x207 .'fflhg -13activity is that amount of tissue factor protein in 10 μΐ of tissue thromboplastin (commercially available from Sigma, St. Louis, MO) as measured by the chromogenic assay. See description of chromogenic assay below. The dose will be dependent aapen the relative activity of the particular species of tissue factor protein, e.g., human tissue factor protein as compared to bovine tissue factor protein. The relative activities can be determined using the chromogenic assay. If, for example, human tissue factor protein is less active by one-half in an im vivo hemophilic dog aodel than the bovine tissue factor protein, then the therapeutic dosage range using human tissue factor protein would be increased by a factor of two. The dose will also be dependent upon various therapeutic variables Including the animal species to be treated, the route of administration, the properties of the tissue factor protein employed, e.g. Its activity and biological half life, the concentration of tissue factor protein in the formulation, the patient's plasma volume, the clinical status of the patient e.g. the particular bleeding disorder, and such other parameters as would be considered by the ordinarily skilled physician.

Tissue factor protein antagonist may be administered by injection intravascularly at a dosage sufficient to correct a bleeding disorder, e.g. QIC. Antagonists may be administered at a dosage sufficient to correct such a bleeding disorder. The dose will be dependent on various therapeutic variables known to the ordinarily skilled artisan.

Tissue factor protein also Is suitably formulated into a topical preparation for loeal therapy for minor bleeding occurring from an accessible site in conjunction with a cold application and gentle pressure. Such a preparation for local therapy includes & therapeutically affective concentration of tissue factor protein in a dermatological vehicle. The .amount of tissue factor protein to be administered and the tissue factor protein concentration in the LC8x267.mhg -14topical formulation, will depend on the vehicle selected, the clinical condition, the species of tissue factor protein used and the stability of tissue factor protein in the formulation.

The tissue factor protein or antagonist of this invention preferably is formulated and administered as a sterile solution although it is within the scope of this invention to utilize lyophilized tissue factor preparations. Sterile solutions are prepared by sterile filtration of tissue factor protein or by other methods known per se in the art Tha solutions are then lyophilised or filled into pharmaceutical dosage containers. The pH of the solution should be in the range of pH 3.0 to 9.5, preferably pH 5.0 to 7.5. The tissue factor protein should be In a solution having a suitable pharmaceutically acceptable buffer such as phosphate, tris (hydroxymethyl) aminomethane-HCl or citrate and the like. Buffer concentrations should be in the range of 1 to 100 mfi. The solution of tissue factor protein may also contain a salt, such as sodium chloride or potassium chloride in concentration of 50 to 750 mM. The compositions of this invention optionally include an effective amount of a stabilizing agent as required such as an albaaia, a globulin, a gelatin, mono or polysaccharide, anino acid or sugar. A stabilizing amount of detergent such as nonioaic detergents (iSG ex block copolymers), sodium deoxycholate, Triton X-100 or sodium dodecyl sulfate (SDS) may be added.

Tissue factor protein or antagonist preferably Is placed into a container having a sterile access port, for example, an intravenous solution bag or vial having a stopper piercable by a hypodermic injection needle.

Systemic administration of tissue factor protein may be made daily or several times a week in the case of replacement therapy for a coagulation factor deficiency. Administration is typically by intravenous injection. Administration may also be LC8x2S7.mhg -15Intranasal or by ocher nonparenteral routes. Tissue factor protein may also be administered via microspheres, liposomes or other microparticulate delivery systems placed in certain tissues including blood.

Example 1 General Materials and Methods Mature bovine brains were obtained from Pel-Freeze, Rogers, Ar., and stored at -20*. Triton X-100 and e-D-methylglucoside were from Calbiochem, San Diego, CA. Concanavalin A-Sepharose resin (referred to as Con A Sepharose in Table 1) was from Pharmacia and Ultrogel AcA 44 from LKB, Gaithersburg, MD. All chemicals and reagents for preparative and analytical sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) were obtained from Bio-Rad Laboratories, Richmond, CA. Factor IXa/Factor X reagent and S2222/12581 were obtained from Helena Laboratories (Kabi Coatest kit, Helena Laboratories, Beaumont, CA. , Catalogue No. 5293). ΎΜ 10 ultrafiltration membranes were from Amicon. Factor VIX was purified from bovine plasma. (Broze, G. and Majerus, P., J. Biol. Chem. 255(4): 1242-1247 [1980]). Factor VXII deficient and normal pooled citrated plasma were from George Xing Biomedicals, Overland Park, Kansas. Crude phosphotidvlcholine (lecithin granules from soya bean) were obtained from Sigma, St. Louis, MO. All other chemicals were of reagent grade or better.

Acetone DelipidatjLim. of Bovine Brains Two mature bovine brains were thawed st room temperature and rinsed free of clotted blood with distilled water. The tissue was than homogenized into ice sold acetone to a volume of 10 ml acetone per gram wet weight of bovine brain using an Ultra-Turrex tissue homogenizer. The homogenate was extracted at 4*0 for 30 min. and then filtered through Whatman No. 1 filter paper on an evacuated flask. The tissue slurry was resuspended In the original LC8x267.whg -16volume of ice cold acetone, extracted and filtered for six times. The final filter cake was dried under a stream of nitrogen and stored at -20’C.

Triton X-100 Solubilization of Tissue Factor Acetone brain powders (145 g) were homogenized in 0.05 M Tris/0.1 M NaCl, pH 7.5 (TBS) to a final volume of 20 ml buffer/g acetone brain powder. The homogenate was extracted at 4®C for 1 hr. and subsequently centrifuged at 10,000 x g for 1 hr. at 4®c. The supernatant was discarded and the pellet re-homogenized into three (3) liters TBS/0.1% Triton X-100. The material was extracted and centrifuged as before. The pellet thus obtained was then homogenized into three (3) liters TBS/2% Triton X-100 to solubilize tissue factor. The homogenate was extracted for 16 hrs. at 4"C and then centrifuged as before.

Concanavalin A-Sepharose Affinity_Colunm The supernatant from the 2% Triton X-100 extraction was made 1 mM in CaClj and MgClj and batch adsorbed with 100 ml Concanavalin-A Sepharose resin for 16 hrs at 4®C. Following adsorption, the Sepharose resin was poured into a 3 x 20 cm column and washed with 500 ml TBS 0.05% Triton X-100 at a flow rate of 2 ml/min. Absorbance was monitored at 230 nM. When no further protein washed from the column, the Sepharose was eluted isocratically with a buffer comprising 100 mg/ml cs-D methylglucoside in TSS/0.05% Triton X-100. Ten milliliter fractions were collected at a flow rate of 2 ml/min. Fractions were relipidated and assayed for tissue factor activity. Tissue factor protein was eluted In approximately four (4) column volumes of eluant. The eluate was concentrated in an Amicon concentration cell using a YM 10 ultrafiltration membrane.

LC8x207.mhg -17Gel Permeation gnromatogxanhv Ten milliliters of concentrated Concanavalin-A Sepharose eluate were dialyzed against TBS 0.1% Triton X-100, pH 7.4, 1 L volume with 4 changes buffer. After dialysis for 8 hours the material was applied to a 120 x 1.5 cm column of AcA 44 Ultrogel pre-equilibrated with TBS 0.1% Triton X-100. The column was developed isocratieally at a flow rate of 6 ml/hr. Ona milliliter fractions were collected. Fractions were ralipidated and assayed for tissue factor activity. Peak fractions were pooled to a final volume of 20 ml. This material was stored at -20’C prior to use.

Purification of.Tissue Factor Protein Tissue factor protein was partially purified from bovine brain by a combination of acetone delipldation, Triton X-100 extraction, lectin affinity chromatography, and gel permeation chromatography. The highly purified tissue factor protein was 12,000 fold purified from brain powders (Table 1). A sensitive chromogenic assay for tissue factor protein was utilized to monitor purification steps. Following detergent extraction of acetone brain powders, the tissue factor protein activity could not be detected in the assay unless tissue factor protein was relipidated. The material which was infused into che rabbits had no cofactor activity prior to relipidatlon in either tha one stage coagulation assay or the two stage chromogenic assay described below (Table 2). This confirmed the well known phospholipid dependence of tissue factor. See Nemerson, ¥., supra. Human placental tissue factor was Isolated using known methods, for example, see Cuba, A. et al. supra. Human placental tissue factor protein was compared to bovine tissue factor protein. As shown in Table 5, both human placental tissue factor and bovine tissue factor have a lipid requirement for activity in an in vitro chromogenic assay. As discussed above, human placental and bovine tissue factors are similar in structure. Thus, human placental tissue factor would be LC8x267.mhg -18expacted to function similarly to bovine tissue factor if infused into rabbits .

Assay for Tissue Factor Protein 1. Chromogenic tissue factor assay.

All samples extracted from bovine brain by non-ionic detergent were ralipidated prior to assay. As discussed above tissue factor has an absolute requirement for phospholipid to exhibit activity in in vitro assay systems (Pitlick and Nemason, Supra). Lecithin granules were homogenized in Tris 0.05 M, 0.1 M NaCl pH7.4 (TBS) containing 0.25% sodium deoxycholate to a concentration of 1 mg/ml. This solution (PC/DOC) was used to relipidate tissue factor as follows. Tissue factor protein was diluted into TBS containing 0.1% bovine serum albumin (TBSA). Fifty microliters were placed in a 12x75mm polystyrene test tube and 50 pi PC/DOC solution was added. Three hundred and fifty (350) microliters TBSA were then added along with 25 pi 100 mM CdClo. This relipldation mixture was allowed to Incubate at 37°C for 30 min.

For the chromogenic assay, relipidated tissue factor protein samples were diluted in TBSA. Ten microliters were placed in a test tube with 50 pi of the factor lXa/factor X reagent and 2 pi of a solution of purified factor VII, 30 units/ml. The tubes were warmed to 37 "C and 100 pi 25mM CaClg were added. Samples were Incubated for 5 min. at 37°C prior to ths addition of 50 pi chromogenic substrata S2222 containing the synthetic thrombin inhibitor 12581. The reaction was allowed to proceed for 10 min. and was stopped by the addition of 100 pi 50% glacial acetic acid solution. Absorbance was detected at 405 nM. A standard curve was constructed using rabbit brain thromboplastin (commercially available from Sigma, St. Louis, MO. catalogue #10263) arbitrarily assigning this reagent as having 100 tissue factor unics/ml. Dilutions wars made from 1:10 to 1:1000. Absorbance was plotted on LC8x267.mhg -19the abscissa on semilog graph paper with dilution of standard plotted on the ordinate. 2. One stage assay for tissue factor activity. 100 pi haemophilic plasma were added to 10 pi of relipidated or lipid free tissue factor or TBSA as control in a siliconized glass tube to prevent non-specific activation through the contact phase of coagulation. The reactants were warned to 37’C and 100 pi 25 nM CaClj were added and clot formation timed. Hvatum, Y. and Pryds, Η., Thromb. Diath. Kaemorrh. 21» 217-222 (1969). fe.SMP-la- Sgfficacy and lack of Toxicity of Tissue Factor Protein in_a_Rabbit Model Arterial and venous cannulas ware Inserted into the ears of two 1.8 kg New Zealand white rabbits. 0.8 ml arterial blood was withdrawn from each animal and sntieoagulated with 0.2 ml 0.13 M trisodium citrate. Both animals were then Infused with 600 pi protein-A purified, human, anti-human factor will antibody, 1700 Bethesda o/ml, through the venous cannula. Thirty minutes after the infusion, arterial cannulas were flushed with 1 sal saline and 1 ml of blood was withdrawn and discarded. 0.8 ml of blood was than sntieoagulated for assay as described above. Three hundred microliters TBS/0.1% Triton X-100 was then infused into the first rabbit as a control while the second rabbit received 300 pi of tissue factor protein. On relipidation, this would represent a dose of 233 tissue factor units per kilogram (ϋ/kg). Sixty minutes after the infusion of the antibody, blood was withdrawn from both rabbits for assay and the arterial cannulas were removed. Blood was collected and flow and duration of blood flow recorded.

LC8x257.«hg -20Rabbit factor VIII cross-reacted with human anti-human factor VIII antibodies in in vitro assay systems. These antibodies were then used to anticoagulate rabbits thus allowing the demonstration of tissue factor protein's factor VIII by-passing activity in vivo. Thirty minutes after the infusion of anti-factor VIII antibodies, no factor VIII was detected in the plasma by chromogenic factor VIII assay (Table 3). Th® eesatr®! rabbit received aa infusion of buffer (300 /il) containing 0.1% Triton St100 thirty minutes before the removal of the arterial vein cannula. This resulted in profuse bleeding which took eleven min. to cease (Table 3). The animal receiving tissue factor protein (test #2, at Table 3) bled only slightly after the same treatment and this flow stopped after 38 seconds demonstrating that tissue factor protein by-passes factor VIII activity in vivo. The animals receiving tissue factor protein had no observed thrombi as had been reported In the literature and discussed above.

The toxicity of the tissue factor protein preparation was tested in six rabbits that were infused with 250 units of tissue factor protein per kilogram. After three days, no adverse effects were observed (Table A). It should be noted that this is the dose used in Tabla 3 wherein the bleeding defect was corrected. Two of the rabbits were then Infused with a second dose of 250 U/kg, one received twice this dose, and one rabbit received 5 times the dose. These animals, as well as two that did not receive a second injection, were monitored for an additional two days. All animals appeared normal after a total of 120 hours of observation, demonstrating that the material is well tolerated and not toxic. Similar preparations of human tissue factor protein would therefore be expected to be well tolerated when infused into patients (Table A) and be able to correct bleeding disorders (Table 3).

LGSx2S7.whg -21Example 3 Efficacy a^d Lack of Togicitv_of Tissue_Factor grotelxi fa a Canine Hemophilia Model Tissue factor protein is infused into hemophilic dogs using the procedure of Giles, A.R. et al.. Blood 60. 727-730 (1982).

Lack of tissue factor protein toxicity w®s first determined ia a normal dog oa bolus injection of 50 tissue faetor protein V/kg and 250 tissue factor protein Π/kg doses. A cuticle bleeding time (C3T) «as performed (Slles supra) prior to iafusioa and 30' sin after each injection. Blood was withdrawn and antieoagulated for coagulation assays at various time points during the experiment (Figure 3) . la order te* demonstrate in vivo factor VIII bypassing activity of tissue faetor protein, experiments were conducted .using hemophilic dogs. Fasting -anissals were anesthetized and a CBT performed prior to any infusion. Tissue factor protein «as then administered by bolus injection and GBTs performed at various time points up· to min after the infusion. Several doses of tissue factor protein were administered. Blood samples were withdrawn throughout the duration of each experiment and assayed for factor V9 prothroimbln and partial thromboplastin tissues. GBTs of greater than 12 min were regarded as grossly abnormal. .Those nails moe cauterized to prevent excessive blood loss.

Aa anesthetized normal dog was administered doses of tissue factor protein representing 50 and 250 Π/kg of tissue factor protein ®s relipidation in the chroeogeuie assay. The GET la this animal was approximately 3 min prior to any infusion (Figure 3). Factor V levels were normal 30 ala after each infusion (Table 6). The prothroBfein and partial tSuroeboplastin times were unchanged at the end of tibe experiment and the GBTs wxe also within the normal ran^e. Thus the infusion of tissue factor protein was well LC8x267 .mhg -22tolerated in normal dogs and no evidence of disseminated intravascular coagulation «as found.

A hemophilic dog with a prolonged CBT characteristic of hemophilia A was administered 50 U/kg of tissue factor protein. The CBT was normalized 30 min after this infusion (Figure 3) . This correction was not associated with an alteration in factor V levels, nor was the prothrombin time lengthened (Table 6). Ta® procoagulant effect was not maintained 90 sin after th® infusion as the CBT effect was again aSnaoswal at this time point. A dose response relationship was established by infusion of 250 tissue factor protein U/kg. At this dose, th® CBT of ths hemophilic dog was normalized at 30 and 50 min (Figure 3) . This increased dosage was, however, associated with a decrease in factor V levels .and a slight lengthening of the prothrombin time (Table 6). As a consequence, experiments were repeated using a dose of 100 tissue factor protein U/kg in order to obtain the maximum duration of efficacy while ensuring that other coagulation factor levels were unaffected. Thus, a hemophilic dog received 100 tissue factor protein U/kg and CBT performed at 15, 30 and AS aim. Interestingly, she CBT at 15 min was still abnormal (Figure 3) and stasis was not achieved until 30 min after the infusion. This is an observation consistent .with results obtained using conventional canine factor Vill preparations ia »a-Inhibitor hemophilic dogs. At this dose, the CBT was normal at 45 min. Blood sanples were taken and analyzed for evidence of consumptive coagulopathy (Table 6). Factor V levels, prothrombin times, throebin clotting tines and platelet levels were unchanged by the treatment. Thus, the efficacy of tissue factor protein in vivo was demonstrated at a dose wSsiich did not cause disseminated intravascular coagulation. The bypassing activity was confirmed in a third hemophilic dog using a dose of 100 tissue factor protein U/kg and CBTs performed at 30 and 45 min. 'while efficacy was established at both time points, some rebleedimg occurred at 45 min.

LC8x267.sahg -23 = ffxasanle . 4 Bam Tissue Factog_P'gateins Functional homology between bovine and human tissue factor proteins was shown using the chromogenic tissue factor assay. Bovine tissue factor protein was purified ss described above. Human tissue factor protein was partially purified from placentae using the method of Freyssinet et al. , Thrombosis and Haemostasis 55,(1):112-118 (1986) including affinity chromatography on Concanavalin-A Sepharose. The eluted material from this column was then subjected to gel filtration chromatography on an AcA 44 Ultrogel column as described earlier for the bovine protein.

Bovina and human tissue factor proteins (referred to as BTFP and HTFP respectively in Table 5) ware assayed in the standard chromogenic tissue factor assay already described. Samples that had been relipidated prior to assay exhibited potent tissue faetor cofactor activity (referred to as BTFP + Pl and HTFP h- Pl respectively in Table 5). Samples that had not been relipidated did not show cofactor activity in the assay (3TFP - Pl and HTFP* Pl).

Protein concentrations in these samples were bovine tissue factor protein 0.59 mg/ml and human tissue factor protein 13.55 mg/ml. The difference in protein concentration was a result of differences in th® degree of purification. These results are evidence of the functional homology between the tissue faetor proteins from human and bovine sources.

LC6«367.Mhs -24Tfflblc a garltication _o£ Boyina Brain Tiisaus Paetor _ . _ .. _ Vol. Protain Tissue Pactos Activity Sp.Act. Puxiiica- Sample wl. ws/"l Total U/sal Total U/lQg tion old 10 Acetone Brain Powders 3,500 7.35 25.725 1.05 3,675 0.14 - TBS Mash Supernatant 3,000 6.04 13,120 0.16 430 - - 15 0.1a Triton Supernatant 3,000 1.42 4.250 0.52 1,360 - - 2a Triton Extract 2,750 3.00 8.250 14.82 40,761 4.04 35.2 20 Con A Sepharose Supernatant 2,730 2.4 5,500 4.2 1,133 - - Con A Sepharose Eluate 420 0.2 71.4 53.5 22,470 314.0 2,242 Con A Eluate Post Concentration 15 1.5 23 750.0 11,250 430.0 3,402 UltrogBl AcA 44 Pool 3 0.33 6.3 1,400 10,780 1,711.0 1 ? 991 «, o< f it A a Table 2 Chagactegisatiom of Partiailly Furifisd Tissue Pactwr Pxetelai Chromogenic Assay Clotting Time 40 Sample ϋ/jal Secs.

TBS/0.1% Triton buffer 0 250 Tissue Factor Protein 0 249 Relipidated TF 1,400 66.2 LC8x267.sahg -25Table 3 Results of in vitro Tissue Factor Protein Bleeding Correction No. Rabbit Infusion Factor VIII U/ml Bleeding Pre 30 sain. 60 min. Time (min) Vol. 1. Control TBS/TX100 5.0 2. Test TFP 233 U/kg* 4.8 11.0 15.2 0.63 0.125 * 233 U/kg of tissue factor activity after relipidation as measured in the chromogenic assay.

Survival after isfesioa of Tissue Factor Protein No. (+/-) Wt (kg) Time 0 Infusion of TFP* 72 Hours Tnfus,ipn_of TFg* Total U 120 Hours Survival UAs Total U U/kg 1 1.42 350 246 350 246 -s- 2 1.35 350 260 350 260 r 3 1.40 350 250 700 500 + 4 1.33 350 263 1,750 1,316 5 1.41 350 248 0 0 •r 6 1.23 350 285 0 0 -i- * Units were determined by chromogenic assay after relipidation of tissue factor protein samples.

LC8x267.mhg -26Tabls 5 Fteictiooial Hioeology betseea Bovin® and. EHuaasa Tissue Factor Sample Assay Dilution Absorbance 405 ma Tissue Factor Activity U/ml BTFP + Pl 500 0.785 800 BTFP + Pl 1000 0.395 755 BTFP - Pl 10 0.000 0 HTFP + Pl 500 0.892 950 HTFP + Pl 1000 0.491 910 HTFP - Pl 10 0.000 0 LC8x26/.mhg -27Table δ Blood Parameters in Normal and Hemophilic Bogs Following Bolus Injection of Tissue Factor Protein Bog Bose ELssue ZactSE Protein (W) Sample Time .Post Infusion (min) FT (sec) PTT (sec) Factor V Π/ml) BMslsts (10&/al) N 50 PRE 12 21 0.81 BD 67 12 22 0.90 3SD 250 30 12 19 1.07 ND 30 12 10 1.22 ND Hl 50 PRE 13 53 1.01 ND 150 13 54 1.03 ND 250 32 15 71 0.64 ND S2 100 PRE 13 51 1.24 205 15 13 51 1.23 169 57 13 51 1.17 223 Coagulation assay results after bolus injection of tissue factor protein in normal and hemophilic dogs.

B — aossal dog BI and B2 ·« hemophilic dogs 30 ND — not determined.

Claims (19)

1. Tissue factor protein lacking phospholipid, for pharmaceutical use,

2. The use of tissue factor protein lacking phospholipid in the preparation of a medicament for treating bleeding disorders which are characterised by a tendency to hemorrhage. 3» Th© use according to claim 2 wherein the bleeding disorder is associated with a deficiency of a coagulation factor. 4. The use according to claim 3 wherein ' the deficient coagulation factor is a deficiency of factor VIII.

3. 5. The use according to claim 3 wherein the deficient coagulation factor Is a deficiency of factor IX.

4. 6. The use according to claim 3 wherein the deficient coagulation factor is a deficiency of factor XXXI.

5. 7. The use according to claim 3 wherein the deficient coagulation factor Is a deficiency of factor XI.

6. 8. The use according to claim 2 wherein the bleeding disorder Is an acquired coagulation disorder.

7. 9. The use according to any one of claims 2 to 8 wherein the medicament is prepared for intravenous administration.

8. 10. The use according to any one of claims 2 to 8 wherein the medicament is prepared for oral administration. XI. The use according to any one of claims 2 to 10 wherein the medicament comprises a therapeutically effective dose in 5 the range of about from 50 U/kg to 250 U/kg.

9. 12. The use according to claim 11 wherein the therapeutically effective dose is in the range of about from 75 ϋ/kg to 200 U/kg.

10. 13. Tissue factor protein antagonist for pharmaceutical use. 10

11. 14. Use of tissue factor protein antagonist in the preparation of a medicament for treating an animal with a hypercoagulative bleeding disorder..

12. 15- A therapeutic dosage form .for administration to an animal with a bleeding disorder characterized by a tendency 15 to hemorrhage comprising tissue factor protein lacking phospholipid and a pharmaceutically acceptable vehicle. lo. The dosage form of claim 15 which Is sterile.

13. 17. The dosage form of claim 15 which is Isotonic to blood.

14. 18. The dosage form of claim 15 wherein the vehicle is a lipophilic sustained release formulation.

15. 19. A therapeutic dosage form for administration to an animal with a bleeding disorder characterized by a hypercoagulative state comprising a tissue factor protein 5 antagonist and a pharmaceutically acceptable vehicle.

16. 20. Use according to claim 1 or 2, substantially as hereinbefore described.

17. 21. Use according to claim 14, substantially as hereinbefore described. 10

18. 22. A therapeutic dosage form according to claim 15, substantially as hereinbefore described.

19. 23. A therapeutic dosage form according to claim 19, substantially as hereinbefore described.