Note: Descriptions are shown in the official language in which they were submitted.
~ 21569g~
I~,e; H~~ . AKT ~ ~N~ T~ C~AFT 1994/BO14--Ma 1040
Dr. Bc/hg
Pharmaceutical which is :3uitable f or employment as an
antidote to blood anticoagulants, and its use
The invention relates to an antidote to blood
anticoagulants .
8100d coagulation is a complex process in which plasma
proteins and cells are involved. Formation of a wound
10 closure is initiated by rapid adhesion of blood platelets
to the damaged surf aces and by proteases and contact
factor3 which are activated successively in a cascade-
like reaction sequence. This course of events leads to
the production of thrombin which, inter alia, catalyzes
15 activation of fibrinogen to form fibrin.
Proteins such as factors VIII and V contribute, as
accelerators, to the Pff;~;Pn~y of this system. In
addition to the protein C sy~tem, inhibitors of the
proteases involved essentially regulate the coagulation
20 processes in such a way that, while wound closure takes
place, excessive reactions are avoided. Disturbance of
this f inely tuned equilibrium can lead to f ibrin
deposition or the formation of thromboses. AS is known,
the vessel occlusions which re~ult ~rom this are t~e
25 cause of many pathophysiological processes 3uch as
cardiac infarction, Ln particular. This problem assumes
particular importance in those patients who are subject
to increased risk of thromboYis, which often represents
a post-operative complication.
30 Various approaches are taken for preventing these
pathophysiological processes. Thus, anticoagulants which
intervene in dif f erent ways in the event of coagulation
are often used in clinical practice to prevent the
formation of a thrombu~ or el~e to support its disso-
35 lution (th~ombolysis). In addition to reducing or pre-
~ venting t~rombocyte functions ~aggregation, adhesion and
21~990
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activation and the synthesis and aecretion of activation
produc ts ), inhibitors of participating coagulation
proteases, in particular of the thromboplastin/factor
VIIa complex, of factor Xa and, in particular, of
5 thrombin (factor IIa) are being investigated and applied.
E~irudin, which was originally isolated from the salivary
glands of the leech ~lirudo m~ n;ll;s~ is a particularly
specific and potent inhibitor of thrombin. In the
interim, a variety of different variants, analogs,
10 fragmellts and mutants of hirudin have become known and
are being investigated for their suitability. While
hirudill is sulfated in its naturally occurring form, it
has been observed that the advantageous biological
activity is also retained in the non-sulfated form. As a
15 consequence, hirudin or its derivatives can conveniently
be prepared by means of genetic manipulation.
The blood anticoagulants also include heparin, and its
fragments and variants, as well as synthetic inhibitors
which inhibit the catalytic activity of thrombin and
20 other coagulation proteases, for example factor Xa. These
components can also be employed in the prophylaxis and/or
therapy of thrombotic or pre-thrombotic complications.
The search for ever more specific and potent
anticoagulants and antithrombotic agents reflects the
25 unsatisfactory situation that the ~l;n;r-;~lly established
substances such as heparins or vitamin K antagonists are
either insuf~;c~;~n~ly effective or else exhibit side
effects which are undesirable and in some cases serious.
3~irudin is currently the most powerful known thrombin
30 inhibitor which does not also interfere wlth the other
enzymes of the blood coagulation cascade. To date,
hirudin has not been observed to have any appreciable
side effects on pulse rate, respiration, blood pressure,
thrombocyte count or the content of fibrinogen or
35 hemoglobin. For this reason, hirudin ls a preferred blood
anticoagulant .
21~6990
, ~
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The u3e o anticoagulants or antithrombotic agents in a
patient naturally entails the risk of increasing the
tendency to bleed which, in extreme situations, for
example in a3sociation with improper use or dosing, can
5 lead to uncontrolled hemorrhages. In order to be able to
counteract the undesirable tendency to bleed in such a
situation, it is possible rapidly to remove some
3ubstances, whose constitution (molecular weight and
structure) p~rmits it, from the blood plasma of the
10 pa~:ient by dialysis. ~owever when this is not possible
due to the lack of appropriate apparatus or for other
reasons, an antidote must be made available.
Some substances or preparations have already been pro-
posed as antidotes. Thus, the thrombins and their blocked
15 variants exhibit a certain hirudin-neutralizing effect;
however, on the one hand, the use of active thrombin in
patients who are being treated with blood anticoagulants
is contraindicated as a rule and, on the other, it is
problematic to prepare inactive thrombin using low
20 molecular weight inhibitors which enter into covalent
bonds, owing to the toxicity of these substances. In
addition, there is a lack of experience with regard to
whether these complexes possibly have an antigenic
effect. Owing to their nature, these complexes are not
25 suitable for neutralizing low molecular weight
(synthetic) antithrombins or antithrombotic agents. While
meizothrombin, an intermediate which arises briefly when
prothrombin is activated to form thrombin, possesses a
certain antagonistic potency, it can transform rapidly
30 into thrombin in vivo and, as such, is contraindicated as
a rule.
Investigation of factor V~I as a hirudin antidote in
appropriate models failed to provide satisfactory
results. European Patent Application EPA 89.810733.9
35 describe3 the use of factor VIII, or fragments of factor
VIII, as antidotes to blood anticoagulants. It is also
known that substances, such as, for example, desmopressin
. , .. . ~
21S~99~
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(Mannucci, P.M., Progress in ~aemostasis and ~hrombosis,
8 (1986), pp. 19-45~, can be used which increase the
concentration of factor VIII in the blood.
Eowever, since even these antidotes are not ade~uate for
5 all areas of application, there is still the need to make
available antidotes to blood anticoagulants, anti-
thrombotic agents and platelet antagonists which are more
effective and have fewer side effects.
Within the scope of the present applic~;orl, anti-
10 coagulatory or antithrombotic substances are understoodto mean glycosaminoglycans and sulfated polysaccharides,
including heparins, in particular unfractionated and low
molecular weight (LMW) pentosan polysulfate, heparan
sulfate, dermatan sulfate or chondroitin sulfate, and
15 also hirudins and their fragments, for example hirugen
(J. Biol. Chem. 265 (1990), 13484-13487; EP-A-0 333 3561,
analogs or mutant~, for example Eirulog~) (W0 92/13952),
coupled hirudins, for example PEG-hirudin or hirutonins,
natural or synthetic inhibitors of the thrombo-
20 plastin/factor VIIa complex, of factor Xa or of thrombin,components of the protein C system, namely activated
protein C, protein S and throm`onmo~l-l;n, inhibitor3 of
fibrin aggregation or crosslinking, substances from the
vitamin ~ antago~ist group, substances which have an
25 effect on platelet activation and/or platelet aggregation
or else platelet adhesion, such as, in particular,
fibrinogen receptor antagonists, or which are able to
increase the endogenous capacity for fibrinolysis, such
as, in particular, PAI-l inhibitors, or stimulators of
30 the synthesis and secretion of ~7~ nngen activator
inhibitors, and thus have an indirect antithrombotic
effect.
It is particularly important to provide a suitable
antidote to the said coupled hirudins, for example PEG-
35 hirudin, since these coupled hirudins can only be removedfrom the organism with dificulty.
21~699~
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It has been found, 3urprisingly, that prothrombin (factor
II) is highly effective a3 an antidote to blood
anticoagulants .
The present invention therefore relates to a pharma-
5 ceutical which contains prothrombin for antagonizingblood anticoagulants, it being possible for these blood
anticoagulants to be selected from the group consisting
of glycosaminoglycans and sulfated polysaccharides, and
also hirudins, and their fragments, analogs or mutants,
lO natural and synthetic inhibitors of the
thromboplastin/factor VIIa complex, of factor Xa or of
thrombin, components of the protein C system, namely
activated protein C, protein S and thrombomodulin,
inhibitors of fibrin aggregation or crossllnking, sub-
15 stances from the vitamin K antagonist group, substanceswhich have an ef fect on platelet activation and/or
platelet aggregation and also platelet adhesion, such as,
in particular, fibrinogen receptor antagonists, or which
are able to increase the endogenous capacity for
20 fibrinolysis, such as, in particular, PAI-I inhibitors or
stimulators of the synthesis and secretion o~ plasminogen
activator inhibitors.
Within the scope of the present invention, prothrombin is
also understood to mean active ~r~ ~ L8 or variants
25 which can be prepared conventionally or, in particular,
by genetic manipulation.
In the pharmaceutical according to the invention,
prothrombin is employed in a concentration of from I to
2000 international units (I~ per kilogram of the
30 bodyweight of the patient to be treated, with concen-
trations of from lO to lO00 IU~kg being particularly
pref erred .
The invention also relates to the use of prothrombin as
an antidote to blood anticoagulants.
~, 21~69~0
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The invention fur~h. -= relateR to a proces~ for
preparing a pharmaceutical which contain3 prothrombin for
antagonlzing blood anticoagulantR.
The pre3ent invention i8 illustrated further by the
5 f ollowing example .
E~xample
Standard human plasma (S~P) to which 20 llg/ml hirudin
were added was investigated in the aPTT te3t for the
antagonizing effect of prothrombin (F II). The coagu-
10 lation times shown in the table verify the effectivenes~of prothrombin.
Ta`ole
aPTT ( 3ec
Control >2 0 0 0 . 0
2 IU factor II 258 . 7
2 IU factor ~r >2000.0
2 IU ~Eactor VI~ >2000 . O
2 IU factor VIII >2000.0
2 IU factor IX >2000 . 0
2 IU factor X . >2000 . 0
