AU2002323670A1 - Method for treating coumarin-induced hemorrhage - Google Patents

Description

METHOD FOR TREATING COUMARIN-INDUCED HEMORRHAGE

BACKGROUND OF THE INVENTION

Vitamin K controls the formation of prothrombin, factor VII, factor IX, and factor X by acting as a substrate for the enzyme γ-glutamyl carboxylase. This enzyme catalyzes the addition of carbon dioxide to the γ-carbon of protein-bound glutamic acid in the gla regions of the coagulation factors.

Coumarin anticoagulants, which include warfarin and dicumarol (dicoumarol), prevent the reduction of vitamin K epoxides in the liver microsomes and induce a state of vitamin K deficiency. A side effect of such anticoagulants is hemorrhage. If hemorrhage does occur, there is a need for a substance to inhibit the coumarin anticoagulant-induced bleeding.

DESCRIPTION OF THE INVENTION

The present invention fills this need by administering factor Xffl to patients afflicted with bleeding due to a coumarin anticoagulant-induced vitamin K deficiency. Factor XE can be administered alone or in conjunction with cryoprecipitate or fresh frozen plasma, generally two units or plasma. Vitamin K can also be administered at an initial dose of 5 to lOmg, generally subcutaneously. The administration of factor XHI can be applied prophylactically or at the time of a bleeding episode.

Factor Xm, also known as fibrin-stabilizing factor, circulates in the plasma at a concentration of 20 μg ml. The protein exists in plasma as a tetramer comprised of two

A subunits and two B subunits. Each subunit has a molecular weight of 83,000 Da, and the complete protein has a molecular weight of approximately 330,000 Da. Factor XHI catalyzes the cross-linkage between the γ-glutamyl and ε-lysyl groups of different fibrin strands. The catalytic activity of factor Xm resides in the A subunits. The B subunits act as carriers for the A subunits in plasma factor XHI. Recombinant factor XHI can be produced according to the process described in European Patent No. 0 268 772 Bl. The level of factor Xm in the plasma can be increased by administering a factor XHI concentrate, derived from human placenta or plasma, called FffiROGAMMTN® (Aventis Corp.) or by administration of recombinant factor XHI. When recombinant factor Xm is used, only the 'A₂'homodimer is generally administered without the 'B₂' subunit. Administration of factor Xm to a subject is generally done intravenously. When administering therapeutic proteins by injection, the administration may be by continuous infusion or by single or multiple boluses. A pharmaceutical composition comprising factor Xm can be formulated according to known methods to prepare pharmaceutically useful compositions, whereby the therapeutic proteins are combined in a mixture with a pharmaceutically acceptable carrier. A composition is said to be a "pharmaceutically acceptable carrier" if its administration can be tolerated by a recipient patient. A suitable pharmaceutical composition of factor XHI will contain ImM EDTA, lOmM Glycine, 2% sucrose in water. An alternative formulation will be a factor XHI composition containing 20 mM histidine, 3% wt/volume sucrose, 2 mM glycine and .01% wt/vol. polysorbate, pH 8.

Other suitable carriers are well known to those in the art. See, for example, Gennaro (ed.), Remington's Pharmaceutical Sciences, 19th Edition (Mack Publishing Company 1995).

The levels of factor XHI in an individual can be determined by assays well known in the art such as the BERICHROM^® F Xm assay (Dade Behring Marburgh GmbH, Marburg, Germany). The normal adult has an average of about 45 ml of plasma per kg of body weight. Each liter of blood has 1000 units (U) of factor Xffl. The amount of factor XDl administered should be enough to bring an individual's level of factor XHI in the plasma to at least 100% of normal plasma or preferably 1-5% above normal. A dose of .45 U/kg would raise the level of factor Xm by about 1% compared to normal. One unit of factor XE is about 10 μg of recombinant factor XHI, which contains only the dimerized A subunit. Thus, to raise the level of factor XHI by 1%, one would administer about 4.5 μg of the A2 subunit per kilogram weight of the individual. So to raise the level 30% of normal, one would administer 13.5 U/kg. For a 75 kg individual this would be about 1,012.5 U. Some patients may have consumptive coagulopathies that involve factor XIII losses. In such cases, a higher dosing {e.g., 1- 2U/kg-%) or multiple dosing of factor Xm {e.g., l-2U/kg-%-day) may be required.

Claims (10)

WHAT IS CLAIMED IS:

1. A method for stopping coumarin anticoagulant-induced bleeding or hemorrhage in an individual comprising administering to said individual a therapeutically effective amount of factor XDl.

2. The method of claim 1 wherein the anticoagulant is warfarin or dicoumarol.

3. The method of claim 1 wherein the factor Xm is administered in conjunction with vitamin K.

4. The method of claim 1 wherein cryoprecipitate or fresh frozen plasma is administered in conjunction with the factor Xm.

5. The method of claim 1 wherein the factor XHI is recombinant human factor Xm.

6. The use of factor Xffl for the production of a medicament for the treatment of coumarin-induced bleeding or hemorrhaging in an individual.

7. The use of factor XDl in conjunction with vitamin K for the production of a medicament for the treatment of coumarin-induced bleeding or hemorrhaging.

8. The use of factor Xm in conjunction with a plasma-derived cryoprecipitate or fresh frozen plasma for the production of a medicament for the treatment of coumarin-induced bleeding or hemorrhaging

9. The use of factor Xm as recited in claims 6, 7 or 8 wherein the coumarin-induced bleeding is caused by warfarin or dicoumarol.

10. The use of factor Xm as recited in claims 6, 7, 8, or 9 wherein the factor X is recombinant factor XE.