Abstract:
The side effect of decrease in body weight caused by the alkylphosphocholines such as miltefosine can be antagonized by certain acetylcholine receptor antagonists such as domperidone and pimozide. The combination of alkylphosphocholine plus the antagonist does not have any effect on the anti-tumor action of the alkylphosphocholine. The combination also caused no new side effects in the animals.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claim priority from German Application No. 19650778.2, filed on Dec. 6, 1996, the subject matter of which is hereby incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to the use of dopamine receptor antagonists in palliative tumor therapy, particularly as agents for antagonizing side effects such as are frequently observed in tumor therapy by means of alkylphosphocholines, particularly miltefosine. 
     2. Background Information 
     It is known and described that the alkylphosphocholine miltefosine causes side effects in patients during the treatment of cancer. These also manifest themselves in patients treated with miltefosine by a marked loss of body weight (Eur. J. Cancer, Vol. 29 A, No. 2, pp. 208-209, 1993). Further side effects of the chemotherapy are: damage to the tissue with a high proliferation rate, leuko- and thrombopenia, decrease in erythrocytes, gastrointestinal disorders, loss of appetite, upper abdominal complaints, disturbed absorption and diarrhea, as well as loss of hair and also liver damage and hyperuricaemia. 
     In a dose-finding study by J. Verweij et al. (J. Cancer Res. Clin. Oncol 118:606-608 (1992)), it was observed that most antiemetics (including 5HT 3  antagonists) were inactive in the prevention of vomiting and nausea. The smallest emetic effect was achieved if miltefosine was taken immediately after eating, domperidone being given 0.5 hours before eating in a dose of 20 mg. In the phase II studies of the same author which were carried out later (Eur. J. Cancer Vol. 29 A, No. 5 p. 779(1993), it was meanwhile found that it was not possible to prevent vomiting either by standard antiemetics or by 5HT 3  antagonists. 
     Since the loss of weight under tumor treatment with alkylphosphocholines leads to a further weakening of the already overloaded body, it was the object of the invention to characterize substances which, in combination with miltefosine or its derivatives, antagonize the known side effects of the alkylphosphocholines such as decrease in body weight. 
     It must be ensured here that the anti-tumor action of miltefosine or its derivatives is not abolished or reduced by combination with the antidote and no additional side effects occur due to the administration of the combination. 
     SUMMARY OF THE INVENTION 
     The above object has now been achieved in that agents for antagonizing side effects such as are frequently observed during tumor therapy by means of alkylphosphocholines, in particular miltefosine, have been found and prepared. These are dopamine receptor antagonists, particularly the two dopamine antagonists domperidone and pimozide. It is to be understood that these agents can be administered both in a fixed combination with the alkylphosphocholine and, in each case, in individual packs and sequentially. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows effects of D-18506 (miltefosine) and domperidone on the body weight of normal rats. 
     FIG. 2 shows effects of D-18506 (miltefosine) and domperidone on the body weight of rats with DM1A-induced breast tumor. 
     FIG. 3 shows effects of D-18506 (miltefosine) and pimozide on the body weight of rats with DMBA-induced breast tumor. 
     FIG. 4 shows effects of D-18506 (miltefosine) and domperidone on DMBA-induced breast tumor of rats. 
     FIG. 5 shows effects of D-18506 (miltefosine) and pimozide on DMBA-induced breast tumor of rats. 
     FIG. 6 shows effects of D-21266 (octadecyl (1,1-dimethylpiperidinio-4-yl)phosphate) on the body weight of normal rats. 
     FIG. 7 shows effects of D-21266 (octadecyl (1,1-dimethylpiperidinio-4-yl)phosphate) and domperidone on the body weight of normal rats. 
     FIG. 8 shows effects of D-21266 (octadecyl (1,1-dimethylpiperidinio-4-yl)phosphate) and pimozide on the body weight of normal rats. 
     FIG. 9 shows effects of D-21266 (octadecyl (1,1-dimethylpiperidinio-4-yl)phosphate) and domperidone on the body weight of rats with DMBA-induced breast tumor. 
     FIG. 10 shows effects of D-21266 (octadecyl (1,1-dimethylpiperidinio-4-yl)phosphate) and pimozide on the body weight of rats with DMBA-induced breast tumor. 
     FIG. 11 shows effects of D-21266 (octadecyl (1,1-dimethylpiperidinio-4-yl)phosphate) and domperidone on DMBA-induced breast tumor in rats. 
     FIG. 12 shows effects of D-21266 (octadecyl (1,1-dimethylpiperidinio-4-yl)phosphate) and pimozide on DMBA-induced breast tumor in rats. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     EXAMPLE 
     Experimental results 
     Comparative studies with respect to body weight changes in healthy and tumor-bearing rats were investigated after administration of miltefosine or octadecyl (1,1-dimethylpiperidinio-4-yl) phosphate alone and in combination with various appetite stimulating compounds. On administration of miltefosine alone, there is a clear loss of weight in the two groups of animals. This is significantly antagonized by the simultaneous administration of domperidone (5×0.1 mg/kg i.p.) or pimozide (5×0.1 mg/kg i.p.) (dopamine antagonists). These effects are observed both in healthy and in tumor-bearing animals (FIGS. 1-3; Table 1). The anti-tumor action of miltefosine is not affected in combination with the two antidotes (FIGS. 4 and 5). 
     
                       TABLE 1______________________________________Changes of body weight (rat)                   D-18506(4 ×         Control   68.1 mg/kg p.o.)         AUC       AUC         day           7       11      7     11    mg/kg i.p.           6.2     22.4    -17.9 -23.5______________________________________Domperidone      0.1      28.6**  62.8**                             28.6**                                   62.8Domp. + D-18506     2.7     10.2  2.7** 10.2*Pimozide   0.2      30.4**  69.8**                             30.4**                                   69.8**Pimo. + D-18506     4.6     12.4  4.6   12.4Metoclo-   0.2      11.5    30.5  11.5**                                   30.5**pramideMeto. + D-16506     -21.4   -36.6 -21.4 -36.6Cypro-     2.5      0.8     15.5  0.8   15.5heptadineCypro. + D-18506    -30.1   57.6  -30.1 -57.6______________________________________ ACU = Area under the curve Dunnett&#39;s T test for variable (AUC) **p &lt; 0.05 in comparison with the control group *p &lt; 0.10 
    
     The decrease in weight in the healthy and tumor-bearing animals which received miltefosine in combination with the dopamine receptor antagonists domperidone or pimozide turns out to be significantly lower than in the rats only treated with miltefosine. The control value (placebo-treated animals), however, is not reached. 
     After administration of the alkylphosphocholine derivative octadecyl (1,1-dimethylpiperidinio-4-yl)-phosphate, there is a lower loss of weight in the with miltefosine. The rats increase in weight less than the control animals (FIG. 6). By the simultaneous administration of the dopamine receptor antagonists domperidone or pimozide, the slower increase in weight of the animals treated with octadecyl (1,1-dimethylpiperidinio-4-yl)phosphate is more than compensated. The animals are actually markedly heavier than the control animals only treated with placebo (FIGS. 7 and 8). 
     The two other appetite-stimulating compounds cyproheptadine and metoclopramide (serotonin receptor antagonists) in combination with octadecyl (1,1-dimethylpiperidinio-4-yl)phosphate had no significant effect on the body weight development of the animals (Table 2). 
     
                       TABLE 2______________________________________Changes of body weight (rat)                   D-21266(4 ×         Control   46.4 mg/kg p.o.)         AUC       AUC         day           7       11      7     11    mg/kg i.p.           11.8    39.8    10.6  37.1______________________________________Pimozide   0.1      31.2**  67.5**                             31.2**                                   67.5**Pimo. + D-21266     23.5    67.3**                             23.5* 67.3**Cypro-     2.5      1.5     20.6  1.5   20.6heptadineCypro. + D-21266    -18.1   -41.2 18.1  -41.2Metoclo-   0.2      19.2    49.4  19.2  49.4pramideMeto. + D-21266     18.4    46.6  18.4  46.6Domperidone      0.1      28.6**  62.8**                             28.6**                                   62.8**Domp. + D-21266     27.9**  66.1**                             27.9**                                   66.1**______________________________________ ACU = Area under the curve Dunnett&#39;s T test for variable (AUC) **p &lt; 0.05 in comparison with the control group *p &lt; 0.10 
    
     In tumor-bearing animals, the same picture results as in healthy animals. Domperidone and pimozide alone and in combination with octadecyl (1,1-dimethylpiperidinio-4-yl)phosphate increase the body weight development of the animals without affecting the anti-tumor action (FIGS. 9-12). 
     The doses of the antidote were selected such that the compounds themselves caused no side effects at all in the experimental animals. 
     These results are surprising since the combination of miltefosine with the similarly appetite-stimulating substances metoclopramide or cyproheptadine does not lead to any positive effect on the decrease in weight in the animals. In contrast, there is instead an increase in the loss of weight (Table 1). A therapeutic use of dopamine receptor antagonists such as pimozide or domperidone was also in no way suggested by the contradictory statements in the art with respect to the effect on nemesis and nausea.