AN ANTICOAGULANT PREPARATION

Abstract: For prophylaxis or treatment of coagulation disorders or cancer an extrinsic pathway inhibitor (EPI) is administered together with heparin or other mucopolysaccharide to the patient. Thereby an increase in coagulant activity is obtained as well as an increase of half-life of injected EPI in plasma.

Description: AN ANTICOAGULANT PREPARATION FIELD OF INVENTION The present invention relates to a preparation for trea¬ ting coagulation disorders or cancer, which preparation comprises a protein with anticoagulant activity and a substance acting synergistically with said protein. The invention further relates to a method of treating coagu- lation disorders or cancer by means of this preparation. BACKGROUND OF THE INVENTION Blood coagulation is a complex process involving many activating and inactivating coagulation factors. Anti¬ coagulant proteins are known to be important for regula¬ tion of the coagulation process (see B. Lammle and J. Griffin (Clinics in Haematology 14. (1985) , 281-342) and anticoagulants are thus important in the treatment of a variety of diseases, eg thrombosis, myocardial infarc¬ tion, disseminated intravascular coagulation etc. Thus heparin is used clinically to increase the activity of antithrombin III and heparin cofactor II. Antithrom- bin III is used for the inhibition of factor Xa and thrombin. Hirudin is used for the inhibition of thrombin and protein C may be used for the inhibition of factor V and VIII. Anticoagulant proteins may also be used in the treatment of cancer. Thus, antistatin has been shown to have anti- metastatic properties (J.H. Han et al., Gene 7_5 (1989), (47-57) . Also heparin and warfarin have been shown to possess antimetastatic properties (G.J. Gasic et al., Int. Rev. Exp. Pathol . 29. (1985) , 173-209) . Coagulation can be initiated through the extrinsic path¬ way by the exposure of tissue factor (TF) to the circu- lating blood (Y. Nemerson, Blood 7_1 (1988) , 1-8) . Tissue factor is a protein cofactor for FVII/VIIa and binding of tissue factor enhances the enzymatic activity of FVIIa towards its substrates FIX and FX. Placenta anti¬ coagulant protein is able to inhibit tissue factor ac- tivity, probably by interfering with TF/FVIIa-phospholi- pid interaction (S. Kondo et al., Thromb. Res. 48. (1987), 449-459). Recently a new anticoagulant protein, the extrinsic pat- hway inhibitor (EPI) has been isolated (Broze et al., Proc. Natl. Acad. Sci. 84. (1987), 1886-1890). On a molar basis EPI has been shown to be a far more potent inhibitor of TF/FVIIa induced coagulation than the placenta anticoagulant protein (R.A. Gramzinski et al., Blood 73. (1989), 983-989). EPI binds and inhibits FXa and the complex between EPI and Xa inhibits TF/FVIIa (SI Rapaport, Blood 7_3. (1989) , 359-365) . EPI is especi¬ ally interesting as an anticoagulant/antimetastatic agent as many tumor cells express TF activity (T. Sakai et al., J. Biol. Chem. 264 (1989), 9980-9988) and becau¬ se EPI shows anti-Xa activity like antistatin. EPI has been recovered by Broze et al. (supra) from HepG2 hepatoma cells (Broze, DK patent application No. 4135/88) . The gene for the protein has been cloned and the protein has been shown to consist of 3 tandem Kunitz type inhibitor domains (Broze, DK patent application No. 3907/88) . The protein consists of 276 amino acid resi- dues and has in addition to the three Kunitz type inhi¬ bitor domains three potential glycosylation sites at position Asnll7, Asnl67 and Asn229. . The molecular weight indicates that some of these sites are glycosylated. Furthermore, it has been shown that Kunitz domain 2 binds FXa while the first Kunitz domain binds FVIIa/TF (Girard et al.. Nature 338 (1989), 518-520). EPI has also been isolated from Hela cells (DK patent application No. 6199/88) and it was shown that HeLa EPI binds heparin. DISCLOSURE OF THE INVENTION The present invention relies on the possibility of in- creasing the anticoagulant activity and the half-life of injected EPI in plasma (i.e. the period of time when EPI circulates in the blood vessels) by concomitantly admi¬ nistering heparin. Accordingly, the present invention relates to a pharma¬ ceutical preparation for the prophylaxis or treatment of coagulation disorders or cancer, which comprises an ex¬ trinsic pathway inhibitor (EPI) protein and heparin or another mucopolysaccharide together with a pharmaceuti- cally acceptable diluent or vehicle. Thus, the present invention utilises the finding that EPI is a heparin-binding protein (cf. Danish Patent Application No. 6199/88) . Furthermore, studies by Sand- set et al. (Thromb. Res. 50. 1988, pp. 803-813) have shown that the natural plasma level of EPI is increased up to two-fold following the subcutaneous injection of heparin. These findings have led the present inventors to assume that circulating heparin prevents the binding of EPI to heparin-like substances (primarily mucopoly- saccharides) on endothelial cell surfaces. Conversely, heparin may also act to release already bound EPI from the endothelium. In any case, it is believed to be es- sential for the anticoagulant activity of EPI that it is found in the circulation rather than bound to endotheli¬ al surfaces. Heparin may therefore be said to exert a synergistic effect on the activity of EPI in that, by binding free EPI or EPI released from the endothelium, it increases the anticoagulant activity of EPI and enables the EPI to circulate in the blood. In vitro stu¬ dies have shown that heparin increases the activity of antithrombin III (L. Rosenfeld, Bioche . J. 237. 1986, pp. .639-646) . However, no increase in the half-life of injected antithrombin III on injection of heparin has been observed, and heparin does not act synergistically with antithrombin III in the case of disseminated intra- vascular coagulation (cf. B. Blauhut, Thromb. Res. 39. 1985, pp. 81-89) . It should be noted that the present invention provides as well preparations in which the EPI protein is combi¬ ned with heparin in such a way that the EPI protein is actually bound to heparin before administration, as pre- parations in which the EPI protein and the heparin are kept in separate containers before use in a form which is adapted to the substantially simultaneous or sequen¬ tial co-administration of the EPI protein and heparin (e.g. with a content of EPI protein adapted to the in- tended use of the preparation, and with a content of heparin which is sufficient to bind substantially all the EPI protein to be administered) . In the latter case, the EPI protein will be bound to circulating heparin in the blood vessels upon administration of both substan- ces . The coagulation disorders which are to be treated by means of the preparation of the invention are primarily disorders which require treatment with an anticoagulant. Examples of such disorders are those which are conven¬ tionally treated by administering heparin alone, e.g. tho bosis, embolism, infarctions or disseminated intra- vascular coagulation. The preparation of the invention is also contemplated to be useful in the treatment of cancer. This utility is suggested by the anti-metastatic properties of other anticoagulants such as antistatin (cf. J.H. Han et al., Gene 75. 1989, pp. 47-57), heparin and warfarin (cf. G.J. Gasic et al., Int. Rev. Exp. Pat- hoi. 29. 1985, pp. 173-209). In the present context, the term "EPI protein" is inten¬ ded to include not only native, or full-length, EPI but also EPI analogues with affinity for heparin. Examples of such analogues are EPI fragments which include the heparin binding domain (believed to be located within the region of the native EPI molecule from the amino acid residue in position 165 to the C-terminal amino residue in position 276, and more specifically assumed to comprise a region rich in positively charged amino acid residues from Arg246 to Lys265) . The term "another mucopolysaccharide" is intended to in- elude heparin-like substances with the ability to bind EPI. Examples of such substances are sulfated glucosami- noglycans selected from heparan sulfate, dermatan sulfa¬ te and protamine sulfate. However, the currently prefer¬ red mucopolusaccharide for the present purpose is heparin, and the invention is explained herein mainly in terms of heparin although this should not be construed as a limitation of the invention to. the use of heparin. The preparation of the invention may be compounded in any form which is suitable for parenteral administration (e.g. for intravenous or subcutaneous injection or in¬ fusion) , for instance by dissolving or suspending the EPI protein and the heparin, either separately or in admixture, as explained above, in sterile water or iso- tonic saline. The dosage level needed to achieve the desired therapeutic effect is estimated on the basis of the content of native EPI in the blood vessels of healt¬ hy individuals and the amount of heparin needed to rele- ase it from the endothelium. EPI is present in the blood of healthy individuals in an amount of 50 ng/ml of plas¬ ma. Injection of, e.g. , 5000 IU of heparin may in theory give rise to the release of EPI from epithelial surfaces to a concentration of up to 500ng/ml of plasma. In order to obtain a significant anticoagulant effect of the EPI protein, it is contemplated that a suitable dosage of EPI (unit dose) may be in the range of about 0.5 -40 mg EPI, i.a. dependent on the type and severity of the con¬ dition for which treatment with EPI is indicated. A cor- responding suitable dosage of heparin is one which is capable of binding this amount of EPI protein to keep it in circulation. Thus, the dosage of heparin to be co- administered with the EPI protein may be in the range of about 1000-15000 IU per unit dose, such as in the range of 2000-10000 IU per unit dose, in particular about 5000 IU per unit dose. In another aspect, the present invention relates to a method of treating or preventing coagulation disorders or cancer, which comprises administering, to a patient in need of such treatment, a therapeutically or prophy- lactically effective dosage of EPI and heparin. In one embodiment of the present method, the administra¬ tion of the EPI protein may be substantially simultane¬ ous with the administration of heparin. This may, for instance be effected by mixing the EPI protein with he¬ parin prior to administration so that the EPI protein will be administered in a form in which it is bound to heparin, or the EPI protein and heparin may be admini¬ stered separately by means of a device which makes it possible to administer two substances simultaneously. Finally, either the EPI protein or heparin may be admi- nistered first and the other component may be admini¬ stered immediately after that ("immediately" meaning any period of time up to one minute after administering the first substance) . In another embodiment, the EPI protein may be admini¬ stered before the administration of heparin. In this case, it is expected that the EPI protein will circulate for only a brief period of time (typically ten minutes) after which it will be bound to heparin-like mucopoly- saccharides on epithelial cell surfaces and thus be in¬ activated. It is, however, envisaged that, analogously with another blood protein (platelet factor 4; cf. G. Cella et al., Eur. J. Clin. Invest. 17, 1987, pp. 548- 554) , the bound EPI will be released by the subsequent administration of heparin and bind to the administered circulating heparin instead. In an alternative embodiment, the EPI protein may be ad¬ ministered after the administration of heparin. In this case, the EPI protein will be bound to the circulating heparin substantially immediately after administration. In order to obtain the desired synergistic effect of heparin, it is contemplated that the EPI protein may be administered 0-24, preferably 0-2, and most preferably 0-0.5, hours after the administration of heparin. In the latter two embodiments, the EPI protein and the heparin will be administered separately from separate containers. As indicated above, the EPI may be admini¬ stered in an amount of 0.5 - 40 mg EPI, and the heparin may be administered in an amount of 1000-15000 IU per unit dose, such as an amount of 2000-10000 IU per unit dose. The coagulation disorders for which the admini- stration of EPI protein and heparin is indicated may be any of those mentioned above. In a further aspect, the present invention relates to the use of an EPI protein and heparin for preparing a medicament for the prophylaxis or treatment of coagula¬ tion disorders or cancer. As discussed in more detail above, the EPI protein may be bound to heparin prior to administration, or the EPI protein and the heparin may be provided in separate containers in a form adapted to the substantially simultaneous or sequential co-admini¬ stration of EPI protein and heparin. The following method may be employed to show EPI activi¬ ty in plasma after administration of the present pre- paration. Assay for EPI activity: EPI was measured in a chromoge- nic microplate assay, modified after the method of Sand- set et al., (Thromb. Res. 42 (1989), 389-400). Heat tre- ated plasma pool was used as a standard. This standard is set to contain 1 U/ml of EPI activity. Standards and samples were diluted in buffer A (.0.05 M tris / 0.1 M NaCl / 0.1 M Na-citrate / 0.02% NaN 3 / pH 8.0) contai- ning 2 ug/ml polybrene and 0.2% bovine serum albumin. FVIIa/TF/FX/CaCl 2 combination reagent was prepared in buffer A and contained 1.6 ng/ml FVIIa (Novo-Nordisk a/s) , human tissue factor diluted 60 fold (Hjort, Scand. J. Clin. Lab. Invest. 9. (1957) , 50 ng/ml FX (Sigma) and 18 mM CaCl 2 . The assay was performed in microplate strips at 37°C. 50 ul of samples and standards were pi¬ petted into the strips and 100 ul combination reagent was added to each well. After 10 minutes incubation, 25 ul of FX (3.2 ug/ml) was added to each well and after another 10 minutes 25 ul of chromogenic substrate for FXa (S2222) was added 10 minutes after the addition of substrate. The reaction was stopped by addition of 50 ul 1.0 M citric acid pH 3.0. The microplate was read at 405 nm. Coagulation assays APTT assay: In the Activated Partial Thromboplastin Time (APTT) assay, 55 μl of plasma incubation mixture was mixed with 55 μl of APTT reagent for 300 seconds at 37° C before 55 μl of 0.025 M CaCl 2 were added, and the coa¬ gulation time was measured. PT assay: In the Prothrombin Time (PT) assay rabbit thromboplastin was dissolved according to the manufac¬ turers instructions and 1 volume of thromboplastin was mixed with 2 volumes of 0.03 M CaCl 2 . In the assay 75 μl of incubation mixtures was mixed with 75 μl of throm- boplastin/CaCl 2 reagent at 37° C before the coagulation time was measured. Dilute tissue factor (dTF) assay: The dTF assay was si- milar to the PT assay. However, in this assay we used human thromboplastin diluted 7.000 fold in coagulation buffer as opposed to be undiluted rabbit thromboplastin used in the PT assay. EXAMPLE Demonstration of a svnergistic effect in coagulation. Coagulation assays were made on plasma samples with ad¬ ded EPI and/or LMW heparin, alle diluted in coagulation buffer (0.1% bovine serum albumin, 50 mM imidazole, 100 mM Nacl, pH 7.3). One sixth of the total volume was rEPI, 1/20 of the volume was LMW heparin. In samples where some of these reagents were not added, coagulation buffer was added to keep the dilution of plasma con¬ stant. All samples were incubated for 15 minutes at room temperature before starting the assay. All clotting ti¬ mes were measured on an ACL 300 R coagulation apparatus from Instumentation Laboratories, Ascoli Piceno, Italy. RESULTS The results are shown in Figures 1-3. From Fig. 1 (APTT assay) it can be seen that addition of 10 μg/ml of rEPI alone increased the APTT coagulation time of normal human plasma by 26 seconds while addition of LMW heparin (0.4 FXal U/ml) alone increased the time by 57 seconds. Coincubation of the two components in amounts as mentioned above resulted in a much greater effect namely prolonging the coagulation time by 283 seconds. Fig. 2 (PT assay) shows that addition of 4 μg/ml rEPI alone increased the coagulation time of normal plasma by 4.4 seconds while addition of LMW heparin (2 FXal U/ml alone increased the time by 10.4 seconds. Coincubation of the two components in amounts as mentioned above pro¬ longed the coagulation time by as much as 141 seconds. Fig. 3 (dTF assay) shows that addition of 0.8 μg/ml of rEPI alone increased the cogulation time of normal plas- me by 35 seconds while addition of LMW heparin (0.2 FXal U/ml) alone increased the time by 105 seconds. Coincuba¬ tion of the two components in amounts as mentioned above prolonged the coagulation time by 341 seconds. Thus, in all three assays the results show a synergistic effect between rEPI and LMW heparin.

Claims: CLAIMS 1. A pharmaceutical preparation for the prophylaxis or treatment of coagulation disorders or cancer, which com- prises an extrinsic pathway inhibitor (EPI) protein and heparin or other mucopolysaccharide together with a pharmaceutically acceptable diluent or vehicle. 2. A preparation according to claim 1, wherein the EPI protein is bound to heparin. 3. A preparation according to claim 1, which comprises EPI protein and heparin in separate containers in a form which is adapted to the substantially simultaneous or sequential co-administration of EPI protein and heparin. 4. A preparation according to any of claims 1-3, wherein the EPI protein is present in an amount of about 0.5 - 40 mg. 5. A preparation according to any of claims 1-4, wherein the heparin is present in an amount of 1000-15000 IU per unit dose, such as an amount of 2000-10000 IU per unit dose. 6. A method of treating or preventing coagulation dis¬ orders or cancer, which comprises administering, to a patient in need of such treatment, a therapeutically or prophylactically effective dosage of EPI and heparin. 7. A method according to claim 6, wherein the admini¬ stration of the EPI protein is substantially simultane¬ ous with the administration of heparin. 8. A method according to claim 6, wherein the EPI pro¬ tein is administered before the administration of heparin. 9. A method according to claim 6, wherein the EPI pro¬ tein is administered after the administration of heparin. 10. A method according to claim 9, wherein the EPI pro- tein is administered 0-24, preferably 0-2, and most pre¬ ferably 0-0.5, hours after the administration of heparin. 11. A method according to any of claims 6-10, wherein the EPI is administered in an amount of about 0.5 - 40mg. 12. A method according to any of claims 6-11, wherein the heparin is administered in an amount of 1000-15000 IU per unit dose, such as an amount of 2000-10000 IU per unit dose. 13. Use of an EPI protein and heparin for preparing a medicament for the prophylaxis or treatment of coagula- tion disorders or cancer. 14. Use according to claim 13, wherein the EPI protein is bound to heparin. 15. Use according to claim 13, wherein the EPI protein and the heparin are provided in separate containers in a form adapted to the substantially simultaneous or sequ¬ ential co-administration of EPI protein and heparin.

Inventors: NORDFANG OLE JUUL, NORDFANG, OLE, JUUL
Applicants: NOVONORDISK AS, NOVO NORDISK A/S
Application year: 1991
Main classification: A61K31
IPC codes: A61K31, A61K38, A61P7, A61P35