EP0482172A1

EP0482172A1 - Anti-tumor agents having reduced toxicity on the basis of cytostatic agents and xanthogenates

Info

Publication number: EP0482172A1
Application number: EP91909541A
Authority: EP
Inventors: Gerhard Sauer; Eberhard Amtmann
Original assignee: Deutsches Krebsforschungszentrum DKFZ
Current assignee: Deutsches Krebsforschungszentrum DKFZ
Priority date: 1990-05-15
Filing date: 1991-05-14
Publication date: 1992-04-29
Also published as: HU9200115D0; IE911650A1; CA2064067A1; WO1991017757A1; HUT62787A; JPH05500067A; AU7870791A; DE4115559A1

Abstract

L'invention se rapporte à un agent antitumoral ayant un effet accru du point de vue synergique, qui est produit sur la base de xanthogénates médicamenteux, éventuellement en présence d'acide monocarboxylique C8-C14 et/ou de son alcali ou de son sel d'ammonium et éventuellement d'un facteur de nécrose tumorale, et qui est caractérisé en ce qu'il contient en outre un agent cytostatique à base d'un métal lourd ou un ester de phosphamide.The invention relates to an antitumor agent having a synergistically increased effect, which is produced on the basis of medicinal xanthogenates, optionally in the presence of C8-C14 monocarboxylic acid and / or its alkali or its salt. ammonium and optionally a tumor necrosis factor, and which is characterized in that it additionally contains a cytostatic agent based on a heavy metal or a phosphamide ester.

Description

Anti-tumor agents having reduced toxicity on the basis of cytostatic agents and xanthogenates

The present invention relates to anti-tumor agents having reduced toxicity on the basis of cytostatic agents and xanthogenates, particularly heavy metal compounds and phosphorus-containing alkylating cytostatic agents such as phosphamide esters and such anti-tumor agents having a synergistic effect.

German laid-open print 31 46 772 describes xanthogenate compounds which have an antiviral effect and are therefore particularly suitable for the treatment of herpes diseases and as prophylactics against influenza. The suitability of a xanthogenate derivative for antiviral chemotherapy is also investigated in Arzneim.-Forsch. 24 ( 2 ) , pages 153 - 157 (1974).

German laid-open print 36 25 948 describes pharmaceutical preparations containing such xanthogenate compounds in combination with an auxiliary compound having at least one lipophilic group and at least one hydrophilic group, particularly fatty alcohol sulfates, fatty alcohol ether sulfates or natural fatty acids being mentioned.

German laid-open print 39 13 791 describes antiviral and anti-tumor agents as a further development, which contain at least one xanthogenate, at least one C₈-C₁₄ fatty acid or an alkali metal salt thereof and the tumor necrosis factor (TNF).

As is known, TNF can trigger necroses in tumors of experimental animals and kill tumor cells in vitro. However, it turned out basically that serious side-effects occur with TNF concentrations necessary to achieve a therapeutic effect. Cytostatic agents on the basis of heavy metal compounds as well as alkylating cytostatic agents, particularly phosphamide esters, are characterized by a good effectiveness in the chemotherapy of tumors. Unfortunately, they are hypertoxic, so that here frequently the same problem exists as with the administration of TNF.

The object of this invention is to develop a combination of active substances which, by the synergistic anti-tumoral effect as well as by a direct detoxication of heavy metal compounds, permits with sufficient effectiveness to substantially reduce the administered amount of cytostatic agent and optionally of TNF as well, if the latter is given simultaneously or separately, so that the undesired sideeffects resulting from the administration of cytostatic agent can be reduced considerably or even eliminated to a large extent even if TNF is administered simultaneously or separately.

This is achieved in that, when administering the classical heavy metal cytostatic agents, particularly cisplatin, lobaplatin and 1,2-bis (aminomethyl)cyclobutane platinum complexes, preferably those of German laid-open print 38 43 571, especially preferably the 1,2-bis(aminomethyl)- cyclobutane platinum complexes having chlorine, L-lactic acid, D,L-2-hydroxy-3-methylbutyric acid, 2-hydroxy-2- methylbutyric acid, glycolic acid, L(-)-3-phenyllactic acid, L-ascorbic acid, maleic acid, malonic acid, oxalic acid, sulfuric acid, palmitic acid, 1,2,3-propanetricarboxylic acid, N-acetyl-alanine, D,L-2-hydroxyhexanoic acid and cyclobutane-1,1-dicarboxylic acid (of. German laid-open print 38 43 571, Example 1), or alkylating compounds, particularly endoxane, holoxane and trofosfamide, or simultaneously administering tumor necrosis factor and these cytostatic agents as well as optionally fatty acid, suitably in the form of water-soluble alkali or ammonium salts, xanthogenate is given as well. The administration is preferably carried out simultaneously in the form of a single combined anti-tumor agent, but the preparation can also be administered in separate doses, possibly also sequentially, wherein the individual components of the preparation can be combined with one another in suitable doses of administration as desired. For sequential administration, the time of administering the individual components shall preferably not exceed a period of about 3 h in toto. For example, in certain cases it proved to be useful to administer the cytostatic agent in combination with xanthogenate and optionally fatty acid, on the one hand, and give TNF within 3 h thereafter. As mentioned above, it is preferred to administer all components simultaneously and thus as a combination.

The essential components of the preparation are represented by the cytostatic agent, on the one hand, and the xanthogenate, on the other hand, since the toxicity of the cytostatic agent is reduced by this combination to such an extent that sufficiently active doses can be administered without excessively undesired side-effects. The same will apply to the addition of TNF if it is still desired. When xanthogenate is administered, fatty acids are preferably given as well. In any case, the fatty acid will be used if the xanthogenate per se is to have an anti-tumoral effect.

The xanthogenates of the general formula

which are known to have antiviral effect from German laidopen print 31 46 772 are the preferably used xanthogenate, the methyl compound and above all the ethyl compound being especially suitable, in particular for the detoxication of the cytostatic agents, above all the heavy metal compounds such as cisplatin. However, the tricyclodecane-9-yl residue is also very suitable for this purpose as well as for the combination of endoxane type compounds. For the present invention and particularly for the just mentioned cases, R² is preferably an alkali metal or ammonium.

As for the rest, residues R¹ and R² generally have the following meanings:

R¹ represents an adamantyl, norbornyl, tricyclodecyl, benzyl, straight-chain or branched C₁-C₂₀ ^_alkyl, C₃-C₂₀- cycloalkyl, iuryl, pyridyl or quinuclidinyl residue, and the above-mentioned straight-chain or branched C₁- C₂₀-alkyl residue may be substituted by a hydroxy, C₁ - C₄-alkoxy group or a halogen atom and the above-mentioned C₃-C₂₀-cycloalkyl residue may also be substituted by a hydroxy, C₁-C₄-alkoxy or C₁-C₄-alkyl group or a halogen atom

and

R² represents a monovalent or polyvalent metal atom, a straight-chain or branched C₁-C₆-alkyl residue which may be substituted by a hydroxy, C₁-C₄-alkoxy, amino, C₁-C₄-alkylamino or (C₁-C₄-alkyl)₂-amino group or (C₁- C₄-alkyl)₃-ammonium group or a halogen atom and represents a 2,3-dihydroxypropyl residue or -hydroxy-(C₁- C₄-alkoxy)-methyl residue.

For the production of a preparation according to the invention 1 part by weight of cytostatic agent and 1 - 100 parts by weight of xanthogenate as well as optionally 1 - 100 parts by weight of a C₈-C₁₄ monocarboxylic acid, which may be present in the form of the alkali or ammonium salts, as well as optionally 0.001 - 0.5 part by weight of tumor necrosis factor are processed together with common carrier and/or diluents and excipients, respectively.

The dosage unit of the preparation contains 1.0 mg to 10 of cytostatic agent and 5.0 mg to 5 g of xanthogenate as well as optionally 50 to 4,000 mg of C₈-C₁₄ monocarboxyli acid and/or 0.001 to 0.5 mg of tumor necrosis factor. For example, the preparation can be administered parenterally (e.g. intravenously, intramuscularly, subcutaneously) or orally. Its dosage unit may always contain the same amounts for the individual components.

It is known that the combination of substances of certain xanthogenates having C₈-C₁₄ fatty acids or an alkali metal salt thereof and tumor necrosis factor has an anti-tumor effect. However, it is surprising that both the xanthogenate per se and said substance combination obviously have a strongly synergistic effect when combined with cytostatic agents, particularly heavy metal salts such as cisplatin, lobaplatin and 1,2-bis(aminomethyl) cyclobutane platinum complexes and alkylating agents such as phosphamides and phosphorus-containing ethyleneimine compounds, e.g. endoxane, holoxane and trofosfamide, and, particularly with respect to the lower alkyl compounds and the cycloalkyl compounds of xanthogenate, have a strongly detoxicating effect for the cytostatic agent. The combination of xanthogenate and optionally TNF and fatty acid with the xanthogenate with these cytostatic agents was by no means suggested, since it had to be expected that the respective toxicities would accumulate. Surprisingly, this is not the case. However, the toxicity of the cytostatic agent including that of TNF is strongly reduced.

Thus, in spite of the reduced dosage of TNF and cytostatic agent the combination of cytostatic agent with xanthogenate and optionally fatty acid as well as optionally TNF results in good therapeutic effects, e.g. with human tumorxenotransplants in athymical mice, as well as simultaneously a sufficient detoxication of cisplatin, for example, whose toxic side-effects limit the dosage thereof.

The following examples serve for explaining the invention.

Example 1

6 NMRI-nu/nu mice of each test group (6 - 8 week-old females) were inoculated subcutaneously with 2 x 10⁶ of small- cell human bronchial carcinoma cells (SCLC). 21 days after the inoculation, when the tumors had reached a palpable size (8 - 10 mm in diameter), therapy was started. All anti-tu- moral therapeutic tests described hereinafter only consisted of a single intravenous infusion into the lateral caudal vein of the mice. The volume of the tumor was measured with a sliding caliper in three dimensions. The injection volume was 0.4 ml per 20 g of body weight, and the solution contained 25 % of bovine serum albumin together with effective components. Recombinant human tumor necrosis factor was made available by the company of Knoll AG. The concentration of tricyclodecane-9-yl-xanthogenate (TCDX) and K salt of the lauric acid (K-C12) was 5 mg/ml.

Fig..1 shows the therapeutic effects of various drug combinations on SCLC tumors in naked mice. The growth of tumors treated with TCDX/K-C12 does not differ from that of the placebo-treated tumors (placebo treatment: 0.9 % of NaCl + 25 % of BSA (bovine serum albumin) without active substances). Both test groups had to be removed from the experiment on the 8th day after the start of treatment because their tumors had grown excessively. The Figure also shows that cisplatin per se and in combination with TCDX/K-C12 develops a certain anti-tumoral effect. A good initial effect results when TCDX-K-C12 is used with TNF, a marked re gression of the tumor size being achieved during the first few days after the treatment. Finally, the therapeutic effect of the combination of TCDX/K-C12 + TNF and cisplatin (10 mg/kg of cisplatin corresponding to a little less than LD₁₀) is demonstrated by means of the graph with the solid square symbols. The tumor volume drastically decreases to about half its initial size by the 8th day, whereas a size of about 500 % has to be calculated for the placebo-treated tumors after this period of time. Some tumors do not start to grow slowly again until later on. However, 100 % of the initial size at the start of treatment were reached again on the 11th day after the treatment.

Example 2

In another experimental setup tumor-bearing animals (experimental approach as described in Example 1) were treated with the combination of TCDX/K-C12/TNF and endoxane in the same model (SCLC). Fig. 2 shows the effect of the combination. Endoxane (120 mg/kg corresponding to 50 % of LD₁₀) was injected intraperitoneally and 0.5 g of TNF/20 g of mouse were applied intravenously three hours later (in the same solution with 25 % of BSA as described in Example 1). As compared to the control growth ( compare placebo controls in Fig. 1), a marked therapeutic effect shows, but the tumor volume does not shrink below its initial size. In contrast thereto, the combination of endoxane with TCDX/K-C12 and TNF (solid triangles) results in a drastic influence in tumor size. The volume shrinks to about half its initial size by the 9th day after the start of treatment, and a slow growth of residual, still surviving tumor cells does not begin until thereafter. (Fig. 2).

Example 3 Another type, the human melanoma HTB72 (American Tissue Culture Collection), was also treated with a combination consisting of TCDX/K-C12/TNF and cisplatin (only 5 mg/kg corresponding to 50 % of LD₁₀). In this connection, it has to be taken into consideration that melanomas in general are regarded as chemotherapy-resistant. This is also shown by the result of Table 1. The tumor volume of the control animals (NMRI, female nu/nu mice, into which 5 x 10⁶ cells were implanted subcutaneously on both sides 4 weeks before the start of treatment) was measured in three dimensions 17 days after a single intravenous infusion (test conditions as described above), and the tumor weight was determined therefrom. The placebo controls (6 animals per experimental group) weighed 241 mg ± 103 on the average, the tumors only treated with cisplatin weighed 259 ± 144 mg, and the tumors treated with cisplatin + TCDX/K-C12 + TNF weighed as little as 108 ± 28 mg. Thus, a marked anti-tumoral effect of cisplatin was rendered possible by the combination with TCDX/K-C12 + TNF; cisplatin per se did not lead to a reduction of tumor growth.

(b) 5 mg/kg of cisplatin + 150 mg/kg of TCDX + 150 mg/kg of K-C12 + 0.5 g/20g of TNF

(c) determined 17 days after the start of treatment.

Example 4

Detoxicating effect of TCDX and ethylxanthogenate on cisplatin

10 mice each (CD₂F₁ females, 6 - 8 weeks old) were inoculated intraperitoneally with various amounts of cisplatin, and directly afterwards various amounts of TCDX or ethylxanthogenate (10 mg/ml in 25 % of BSA, 0.9 % of NaCl) were infused into the lateral caudal vein. The development of weight of the experimental groups was supervised and their survival was recorded.

Fig. 3a shows a dose-effect curve, expressed by the weight loss of the treated mouse groups as a function of the cisplatin concentration.

Fig. 3b shows the detoxicating effect of TCDX on cisplatin which expresses itself in the reduced loss of weight of the animals treated with cisplatin.

Fig. 3c finally illustrates the detoxicating effect of ethylxanthogenate. From this result, the conclusion can be drawn that the xanthogenate structure per se is responsible for the detoxicating effect.

Fig. 4 once again shows the detoxicating effect of TCDX, and the statistical significance of the results is proved by error bars.

The reduction of the letal effect of cisplatin after the infusion of varying xanthogenate concentrations is shown in the following Figures. 100 % of the experimental animals survive only after the application of 9.38 mg/kg of cisplatin. In contrast thereto, one animal of the group which obtained 12.5 mg/kg dies after 6 days only. Doses of 15 mg and above are letal for all animals as early as 4 days after the treatment (Fig. 5).

Fig. 6 illustrates that the additional application of 200 mg/kg of TCDX markedly prolongs the lives of the animals, also those of the group which obtained 20 mg/kg of cisplatin. In this group, the survival period of some animals is prolonged by up to 33 %. As follows from Fig. 7, the prolongation of the survival period becomes even more favorable after the additional administration of ethylxanthogenate (which does not develop an anti-tumoral effect per se).

Example 5

Detoxicating effect of ethylxanthogenate on cisplatin

In another test setup, 4 mice each (P388-leucemia mice ) were inoculated intraperitoneally with 10 mg/kg of platinex solution (cisplatin) and various amounts of ethylxanthogenate (200 mg/kg, 500 mg/kg) were administered orally directly afterwards. In this case, 1.0 ml of the respective ethylxanthogenate solution (3x tonically sodium phosphate pH 8.5) were administered per 20 g of body weight by means of the probang. The weight development of the experimental groups was checked and their survival period was recorded (Table 2 and Fig. 8).

Example 6

Another measuring parameter for detoxication is the measurement of the blood urea (BUN) after cisplatin treatment which causes damage of the kidneys. As a result, BUN rises in treated animals. Xanthogenate reduces the BUN values significantly.

Determination of blood urea

10 mg/kg of cisplatin (platinex solution 0.5 mg of cisplatin/ml) were injected intraperitoneally into mice (NMRI-Nu/Nu, female, 6 - 8 weeks old). 200 mg/kg of TCDX (in 25 % of bovine serum albumin, 0.9 % of NaCl, 10 mg/ml of TCDX) or placebo solution were infused intravenously directly afterwards. The body weights and the blood urea concentrations (BUN) were determined by means of a buyable kit (Sigma, Munich; method according to Crocker) after four days.

Claims

1. An anti-tumor agent having a synergistically increased effect on the basis of xanthogenate drug, optionally in the presence of C₈-C₁₄ monocarboxylic acid and/or its alkali or ammonium salt and optionally tumor necrosis factor, characterized in that it contains additionally a cytostatic agent on the basis of heavy metal or a phosphamide ester.

2. The anti-tumor agent according to claim 1, characterized in that the xanthogenate which it contains is a C₁-C₂₀-alkyl xanthogenate or a C₆-C₃₀-cycloalkyl xanthogenate, preferably in the form of alkali or ammonium salt.

3. The anti-tumor agent according to claim 1 or 2 , characterized in that the cytostatic agent on the basis of heavy metal which it contains is cisplatin, lobaplatin or a 1,2-bis(aminomethyl)cyclobutane platinum complex.

4. The anti-tumor agent according to claim 1 or 2, characterized in that the cytostatic agent on the basis of phosphamide ester which it contains is endoxane, holoxane or trofosfamide.

5. The anti-tumor agent according to any one of claims 1 to 3, characterized in that it contains xanthogenate and monocarboxylic acid in combination with cisplatin, lobaplatin or a 1,2-bis(aminomethyl) cyclobutane platinum complex.

6. The anti-tumor agent according to any one of claims 1,2 or 4, characterized in that it contains xanthogenate and monocarboxylic acid in combination with endoxane, holoxane or trofosfamide.

7. The anti-tumor agent according to any one of claims 1 to 3, characterized in that it contains xanthogenate in combination with a cytostatic agent on the basis of heavy metal, particularly cisplatin, lobaplatin or a 1,2-bis(aminomethyl)cyclobutane platinum complex.

8. The anti-tumor agent according to any one of claims 1 to 7, characterized in that the xanthogenate which it contains is methyl or ethyl xanthogenate.

9. The anti-tumor agent according to any one of claims 1 to 8, characterized in that it is present as a kit in which one or more of the individual substances, each separated in effective doses, is present in a separate form.

10. A product containing a cytostatic agent on the basis of heavy metal or a phosphamide ester and a xanthogenate as well as optionally a C₈-C₁₄ monocarboxylic acid and/or its alkali or ammonium salt and optionally the tumor necrosis factor as a combined preparation for the simultaneous, separate or seguential use in cytostatic therapy.

11. The product according to claim 10, characterized in that cisplatin, lobaplatin or a 1,2-bis(aminomethyl)- cyclobutane platinum coplex is present as the cytostatic agent on the basis of heavy metal.

12. The product according to claim 10, characterized in that endoxane, holoxane or trofosfamide is present as the cytostatic agent on the basis of a phosphamide ester.

13. The product according to any one of claims 10 to 12, characterized in that methyl or ethyl xanthogenate is present as the xanthogenate.

14. A process for the production of a product according to any one of claims 10 to 13, characterized in that 1 part by weight of cytostatic agent and 1 - 100 parts by weight of xanthogenate as well as optionally 1 - 100 parts by weight of a C₈-C₁₄ monocarboxylic acid, which may also be present in the form of the alkali or ammonium salts, as well as optionally 0.001 - 0.5 parts by weight of tumor necrosis factor are processed together with common carriers and/or diluents and excipients, respectively, which, in the dosage unit, contains 1.0 mg to 10 g of cytostatic agent and 5.0 mg to 5 g of xanthogenate as well as optionally 50 to 4,000 mg of C₈-C₁₄ monocarboxylic acid and/or 0.001 to 0.5 mg of tumor necrosis factor.

15. Use of xanthogenate and a cytostatic agent on the basis of heavy metal or a phosphamide ester and a xanthogenate as well as optionally a C₈-C₁₄ monocarboxylic acid and/or its alkali or ammonium salt and optionally the tumor necrosis factor for controlling cancer.

16. Use according to claim 15, characterized in that methyl or ethyl xanthogenate is used as the xanthogenate.

17. Use of xanthogenate for the production of a pharmaceutical preparation for the cytostatic control of cancer.

18. Use according to claim 17, characterized in that methyl or ethyl xanthogenate is used as the xanthogenate.