Thrombosis Treatment With Fibrinolytics and Prostacyclins

This invention relates to the use of a combination of a fibrinolytic and a prostacyclin analogue for thrombosis treatment, and to the corresponding combination product.

According to K. H. Gold et al. Circulation 68, I-50 to I-54 (1983) and W. Ganz et al. Amer. Heart J. 101, 4 (1981), the recurrence of thrombosis (rethrombosis) after an initially successful thrombolysis, continues to represent a problem in fibrinolytic therapy. As pathogenic mechanisms, these mention the presence of a damaged and thus a thrombogenic vascular inner wall on the originally thrombosed site after dissolution of thrombi, and in many cases a bleeding anomaly induced by stenoses. Thrombogenic surfaces and rheological disturbances result in renewed activation of the plasma clotting system and thrombocytes (platelets).

In his article "Pharmacology of Streptokinase" (from the manual "Experimental Pharmacology 46: Fibrinolytics and Antifibrinolytics, F. Markward (ed.), Springer-Verlag, Berlin-Heidelberg-New York, 1978, 151-177), H. P. Kloecking writes that, particularly after thrombolysis with streptokinase and urokinase but to a lesser extent also after use of t-PA and pro-urokinase, cleavage products of fibrinogen and fibrin occur. These result in an increased aggregation tendency of platelets and thus promote quick new growth of platelet thrombi on the original site of a lysed thrombus.

Current clinical prophylaxis of fast rethromboses involve the inhibition of plasmatic clotting by heparin. E. Hiller comments on this in the Muenchner medizin. Wochenschrift 126, 13 (1984). He considers a prophylaxis with heparin as problematic, since platelet-induced rethromboses are not thereby prevented. According to his data, these are more likely even promoted. According to Kloecking, because of the consumption of the clotting factors, the plasmatic clotting system is no longer fully functioning especially after thrombolysis with streptokinase or urokinase. By the additional administration of heparin, thus, the danger of bleeding is promoted.

To what extent platelets and to what extent the plasmatic clotting system are involved in rethrombosis is indeed often discussed but still has not been clarified.

It is an object of this invention to provide a new product and method of thrombolysis which also prevents and/or lowers or minimizes the probability of a rethrombosis after thrombolysis.

Upon further study of the specification and appended claims, further objects and advantages of this invention will become apparent to those skilled in the art.

These objects have been achieved based on the findings that rethrombosis after thrombolysis can be prevented and/or made less likely by administration of fibrinolytics and prostacyclin analogues together for dissolution of thrombi.

Activation, aggregation and adhesion of platelets have a decisive role in rethrombosis after successful thrombolysis. By the action of the prostacyclin analogues in inhibiting platelet aggregation, no rethrombosis occurs from the beginning of the treatment.

Suitable prostacyclin analogues for use according to this invention include carbacyclin derivatives, e.g., those described in U.S. Pat. No. 4,692,464 which is a divisional application of U.S. Ser. No. 086,506, filed Oct. 19, 1979 (equivalent to DE-OS-2845770) now abandonded; U.S. Ser. No. 745,989, filed Jun. 18, 1985, now abandonded which is a continuation of U.S. Ser. No. 464,550, filed Feb. 7, 1983 now abandonded (equivalent to DE-OS-3204443); U.S. Ser. No. 803,453 of Nov. 29, 1985, now abandonded which is a continuation of Ser. No. 581,851 of Feb. 2, 1984 (equivalent to DE-OS-3306123); U.S. Ser. No. 859,977 of May 5, 1986, now abandonded which is a continuation of Ser. No. 510,121 of Jul. 1, 1983 (equivalent to DE-OS 3226550) now abandonded; inter alia, all of which documents are entirely incorporated by reference herein.

Other suitable prostacyclin analogues are the prostacyclins per se, e.g., as disclosed in U.S. Pat. Nos. 4,191,694; 4,219,479; 4,315,013; 4,364,950; 4,378,370; 4,466,969 in each case, suitable species being routinely selected in accordance with whether they have thrombocyte aggregation inhibition activity.

More generally, this invention relates to the combination of a fibrinolytic with any agent having thrombocyte aggregation inhibition activity, the use of such a combination being analogous to that described herein for the combination of a fibrinolytic with a prostacyclin analogue.

Preferred carbacyclins for use according to the invention are:

5-{(E)-(1S,5S,6R,7R)-7-hydroxy-6-[(E)-(3R,4RS)-3-hydroxy-4-methyl-oct-1-en- 6-yl]-bicyclo[3.3.0]octan-3-ylidene}-pentanoic acid (Iloprost)

(5E)-(16RS)-13,14-didehydro-16,20-dimethyl-18,18,19,19-tetradehydro-6a-carb aprostaglandin-I.sub.2,

(5E)-(16RS)-13,14-didehydro,1a, 1b-dihomo-16,20-dimethyl-3-oxa-18,18,19,19,-tetradehydro-6a-carbaprostagla ndin-I.sub.2 or 5-(E)-{1S,5S,6S,7R)-7-hydroxy-6-[(3S,4S)-3-hydroxy-4-methyl-nona-1,6-diiny l]-bicyclo[[3.3.0]octan-3-ylidene}-3-oxa-pentanoic acid.

Streptkokinase, urokinase and t-PA, as well as pro-urokinase and pro t-PA, are suitable as fibrinolytics.

The carbacyclins are administered in amounts in the range otherwise customary for inhibition of platelet aggregation. The precise amount to be used per this invention depends on the extent of the thrombosis and the rethrombosis which is expected, as well as on the usual factors affecting precise dosage determination for a given patient. The amount of fibrinolytic used is the same as or less than would otherwise be used according to conventional therapy with the particular fibrinolytic involved. Thus, the administration of each agent of the combination per this invention is analogous to the conventional administration of the respective individual agents for purposes of thrombolysis (the fibrinolytic) or platelet aggregation inhibition (the prostacyclin analogue).

A typical human unit dose of the prostacyclin analogue for use in this invention is, depending on the mode of application, 10 pg to 1 mg i.v. or 10 .mu.g to 500 mg p.o., preferably 0.1 to 100 .mu.g, most preferably 0.091-10 .mu.g/kg body mass/min. of Iloprost i.v. or a biologically equivalent amount of another prostacyclin analogue. A typical unit dose of the fibrinolytic agent is 5000 IU to ten million IU of streptokinase, preferably 50,000-5,000,000 IU, most preferably 250,000-2,000,000 IU or a biologically equivalent amount of another fibrinolytic agent. Typically, the weight ratio of fibrinolytic to prostacyclin analogue is about 10.sup.7 :1 to about 10.sup.2 :1, preferably 10.sup.5 :1 to about 10.sup.3 :1.

The total dose of the combination of this invention is normally achieved by administration of a correspondingly lower dosage, e.g., parenterally, over a period of time, e.g., 1-6 hrs.

Normally, both agents are administered simultaneously for the same period of time. However, it is also possible to commence the administration of the prostacyclin analogue prior to or after initiation of the fibrinolytic agent. It is also possible to continue the treatment of the prostacyclin analogue after the termination of the fibrinolytic agent.

The two kinds of agents can be administered in the same dosage unit or can be administered in separate dose units. They can be administered to mammals, including humans, in the forms of conventional galenic formulations, for example, as described in the preceding references.

The combination according to the invention is preferably infused or injected intrasmuscularly. In the case of parenteral use of streptokinase, urokinase, t-PA, prourokinase and pro-tPA, the carbacyclins used in the combination can also be administered orally.

Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. The following preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever.

In the preceding text and the following example, all temperatures are set forth uncorrected in degrees Celsius and all parts and percentages are by weight; unless otherwise indicated.

Catheters for infusion and electric stimulation by peripheral arteries were placed in the left descending coronary artery on 10 anesthetized beagle dogs (anesthesia with Tramadol, 2 mg/kg i.v.+0.5 mg/kg/h i.v.; Imbretil.RTM., 0.33 mg/kg i.v., N.sub.2 O/O.sub.2 80:20). Intracoronary stimulation with a current intensity of 250 uA was continuously applied for thrombus induction. The growth of a coronary thrombus up to complete occlusion was assessed in 15-minute intervals by intracoronary injection of the contrast medium Urografin.RTM. 76 with X-ray control. With complete occlusion of the coronary artery, streptokinase (250 I.U./kg/min) was infused intracoronarily until recirculation was determined by X-ray. In 5 animals only streptokinase was infused intravenously, in the other 5 animals, the prostacyclin analogue Iloprost (50 ng/kg/min) was additionally infused intravenously.

In 10/10 animals, the streptokinase infusion, in an average of 60 min., resulted in the reopening of the coronary artery previously completely occluded by thrombosis.

In 5/5 dogs which received streptokinase solely, on an average of 21 min. after reopening, a complete reocclusion by rethrombosis occurred spontaneously.

When, in addition to streptokinase, Iloprost was infused intravenously, rethrombosis did not occur in any of the 5 animals within this period. Also, no rethrombosis occurred on one dog which, in addition to streptokinase, received, instead of Iloprost, 5-{(E)-(1S,5S,6S,7R)-7-hydroxy-6-[(3S,4S)-3-hydroxy-4-methyl-nona-1,6-diin yl]bicyclo-[3.3.0]octan-3-ylidene}-3-oxapentanoic acid in a dosage of 5 ng/kg/min.

The preceding examples can be repeated with similar success by substituting the generically or specifically described reactants and/or operating conditions of this invention for those used in the preceding examples.

From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention, and without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions.