GB2095997A - Treatment of tumor cell metastasis and growth - Google Patents

Description

SPECIFICATION

BACKGROUND AND PRIOR ART Method for treating tumor cell metastasis and growth The primary goal of cancer treatment is treatment and eradication of the growth of the primary tumor. Concurrent with this treatment it is necessary to prevent metastasis, which can be defined as separation of primary tumor cells and their subsequent penetration into the lymphatic system or blood vessels for dissemination. Such dissemination may occur by adhesion to and subsequent penetration through the endothelial walls, establishment of secondary tumors in the perivascular tissues and eventual spread of the tumor cells to more distant sites. Although much is known aboutthe clinical manifestations of the metastatic process, little is understood about the biochemical, immunologic, genetic, and hormonal mechanisms involved in metastasis.Thus metastasis can be considered as a single phenomenom represented by an intricate series of events. Because of the importance of both treatment of primary tumor growth and prevention of metastasis, cancer researchers have undertaken extensive research to define the interactions involved in tumor growth and metastasis. One of the biological properties which tumor cells appear to posess is the ability to interact with and to attach to host blood platelets, enhancing the potential of the tumorto lodge in the microvasculature and adhere to vascular endothelium. Alternatively, it has been suggested that following lodging of the tumor cells, the cells may initiate the formation of surrounding protective platelet thrombi. For successful metastasis to occur, the metastatic cells must first lodge and adhere to the vascular endothelium and remain intravascular until it infiltrates into the surrounding tissue. Because of the similarities of the process involved in the lodging and adherance of the tumor cells to the endothelium and the formation of non-tumor thrombi, many investigators have concluded that platelets are involved in some fashion. Because of this platelet involvement, numerous investigations have been undertaken to determine the effect of anticoagulant therapy on metastasis. The investigations referred to below involved the administration of anticoagulant compounds which are potent inhibitors of platelet aggregation. The results to date have been ambivalent. Heparin has been reported to both decrease and increase metastasis, especially pulminary, [See CellBiol. Intl. Rep.2: 81-86 (1963) andArch. Surg. 91: 625-629 (1965)]. Aspirin has produced mixed results [See Eur. J. Cancer 8: 347-352 (1972) and Intl. J. Cancer 11: 704-718 (1973)]. Warfarin has been demonstrated to produce significant antimetastatic effects after intervenous injection of tumor cells and in spontaneously metastasizing tumors [See Cancer 35: 5-14 (1975) and CancerRes 37: 272-277 (1971 )]. It has been shown that metastasis induced by intravenous administration of B-16a melanoma cells can be prevented by administration of the anticoagulant agent prostacyclin [See CellBiol. 87: 649 (1980)]. For a review of the use of anticoagulants in tumor therapy, see M. B. Donati, et. al., Malignancy and the Hemostatic System, pp. 103-120, Raven Press, 1981. It has been suggested that the use of anticoagulant therapy has been less than satisfactory in part because of the lack of specificity of the anticoagulant agents used and the fact that some of the agents produce effects on the tumor cells themselves which may overall, negate the desired effect on blood platelets, and hence metastasis. According to the present invention, the compound 3-Methyl-1-[2-(2-naphthyloxy)-ethyl]-2-pyrazolin-5-one disclosed and claimed as a therapeutically efficacious antithrombotic agent in U.S. Patent No. 4,053,621, has been found to be a potent antimetastatic agent, with accompanying antineoplastic activity.

SUMMARYOFTHE INVENTION The present invention is directed to a therapeutic method for reducing metastasis and neoplastic growth in a mammal. The method involves administering to the mammal a therapeutically effective amount of 3-Methyl-1-[2(2-naphthyloxy)-ethyl]-2-pyrazolin-5-one.

DETAILED DESCRIPTION OF THE INVENTION As disclosed in U.S. Patent No. 4,053,621, the methylpyrazolone compound used in the present invention (represented by Formula I below), can be prepared by various routes of synthesis as illustrated below. According to Process A, 2-(2-naphthyloxy)-ethylhydrazine is reacted with an acetoacetic acid derivative; according to Process B, 3-methylpyrazolinone-(5) is reacted with a 2-(2-naphthyloxy)ethyl derivative; according to Process C, 2-(2-naphthyloxy)-ethyl-hydrazine is reacted with a tetrolic acid derivative.

Diluents which can be used include all inert organic solvents, optionally diluted with water, e.g., hydrocarbons such as benzene and toluene; halohydrocarbons such as methylene chloride; alcohols such as methanol and ethanol; and organic basis such as pyridine and picoline. Basic or acid condensation agents can be used, and the reaction temperature can be varied between 10[deg] and 200[deg]C. The compound can be easily purified by conventional means by recrystallization from a suitable solvent. In the present specification the expression "pharmaceutically acceptable diluent or carrier" means a non-toxic substance that when mixed with the active ingredient or ingredients renders it suitable for administration. The expression preferably excludes water and low-molecular weight organic solvents commonly used in chemical synthesis, except in the presence of other pharmaceutically necessary ingredients such as salts in correct quantities to render the composition isotonic, buffers, surfactants, coloring and flavoring agents, and preservatives.Examples of suitable solid and liquid diluents and carriers are the following: water containing buffering agents which can be rendered isotonic by the addition of glucose or salts; non-toxic organic solvents; such as paraffins, vegetable oils; alcohols; glycols; natural ground rock (for example kaolins, aluminas, talc or chalk); synthetic rock powders (for example highly dispersed silica or silicates); and sugars. Oral administration can be effected utilizing solid and liquid dosage unit forms such as powders, tablets, dragees, capsules, granulates, suspensions, solutions and the like. Where appropriate, dosage unit formulations for oral administration can be microencapsulated to prolong or sustain the release as for example by coating or embedding particulate material in polymers, wax or the like. Parenteral administration can be effected utilizing liquid dosage, unit forms such as sterile solutions and suspensions intended for subcutaneous, intramuscular or intravenous injection. These are prepared by suspending or dissolving a measured amount of the compound in a nontoxic liquid vehicle suitable for injection such as an aqueous or oleaginous medium and sterilizing the suspension or solution. Stabilizers, preservatives and emulsifiers can also be added. Generally the parenteral dosage will be from 0.01 to 50 mg/kg, preferably from 0.1 to 10 mg/kg, of body weight per day, and the oral dosage form will be from 0.1 to 500 mg/kg, preferably 0.5 to 100 mg/kg, of body weight per day. The following procedure was used to determine the antimetastatic and antineoplastic properties of 3-Methyl-1-[2-(2-naphthyloxy)-ethyl]-2-pyrazolin-5-one. The test protocol utilized two unrelated murine tumor types (a melanoma and a carcinoma) to minimize the possiblitythethe results obtained are "unique" to a single tumor type. Both of these tumors are routinely used for basic studies on the mechanism of metastasis and antineoplastic activity. A. In vivo maintenance oftumorlines Subcutaneous B-16 amelanotic melanoma (B-16a) and Lewis Lung carcinoma (3LL) were obtained from the Division of Cancer Treatment, (NCI), Animal and Human Tumor Bank, Mason Research Institute, Worcester, Massachusetts. Both types of tumors were passaged four times after receipt. Passage involved subcutaneous implantation of a 2 x 2 mm tumor dice in the right axiallary region (using a 13 gauge trocar needle) of male, syngeneic host mice [(C57BU6J; Jackson Laboratory Strain]. The host mice were between 17-22 g (approximately 28 days old) and housed under identical conditions of photoperiod, feeding regimen, temperature, etc. The transplanted tumors were allowed to grow in the syngeneic host mice for approximately 14 days following implantation. B. Isolation and suspension of tumor cells Tumor cells were then obtained from the host mice by aseptic removal and dispersed using sequential collagenase digestion, as described below. The removed tumors were diced (4 x 4 mm) and the diced tissue divided (approximately 500 mg/flask) between 6-8 sterile polycarbonate Erhlenmeyerflasks. A 10 ml portion of a "tumor dispersion solution" (TDS) was added to each flask. The TDS was prepared by mixing together Composition A and Composition B described below.

COMPOSITION A

The antibiotics were added to ensure that bacterial contamination did not occur. Composition B is a dry mixture containing collagenase low in clostripain and other proteolytic activity; deoxyribonuclease (DNase) to dissolve deoxyribonucleo-protein released from damaged cell nuclei; lima-bean or soybean trypsin inhibitors to exclude any residual tryptic activity; human serum albumin to eliminate nonspecific protease activity and absorb peroxy and hydroperoxy fatty acids liberated from damaged membranes.

COMPOSITION B

Composition B was weighed out and placed in a flask and 100 ml of Composition A added. The diced tissue in the TDS was then dispersed (30 min., 37[deg]C) under air in a Dubnoff Metabolic Shaker (90 oscillations/minute). Supernatants were collected through cheesecloth into sterile 50 ml polycarbonate round bottom centrifuge tubes and centrifuged for 10 minutes (25[deg]C) at 900 rpm (100 xg) in a Sorvall SS-34 rotor. Following centrifugation, the supernatant fraction was discarded. The solid cellular matter (pellets) obtained were washed twice with MEM solution, resuspended in MEM and held at 4[deg]C. A 10 ml portion of TDS was added to the remaining diced tissue and the tissue incubated in a metabolic shaker as described hereinabove, except for a period of 60 minutes. The centrifugation was repeated and the resuspended cells were combined. The cell viability was determined by the vital dye exclusion method [See Exptl. CellRes. 13: 341-347 (1957)]. The cell count was determined in a hemocytometer. The stromal cell contamination e.g. macrophages, red blood cells, etc. was determined by visual examination under a microscope. The final cell suspension obtained consisted of greater than 99 percent monodispersed cells with approximately 25 percent host stromal cell contamination. Typical yields from a 3.0 g B-16a or 3LL tumor ranged between 9 x 10$ and 1.3 x 109 viable tumor cells. The final cell suspensions were than subjected to contrifugal elutriation for final separation of the tumor cells. In centrifugal elutriation, cells are subjected to two opposing forces within a separation chamber; a centrifugal field generated by a spinning rotor and a counterflow of fluid in the opposite (centripatal) direction. A sample suspended in a medium enters the separation chamber. Each cell tends to migrate to a zone where its sedimentation rate is exactly balanced by the flow rate of the fluid through the separation chamber. The chamber's geometry produces a gradient of flow rates from one end to the other; cells with a wide range of different sedimentation rates can be held in suspension.By increasing the flow rate of the elutriating fluid (separation medium) in steps, or by decreasing the rotor speed, successive populations of relatively homogenous cell sizes can be washed from the chamber. Each population will contain cells which are larger or more dense (i.e. faster sedimenting) than those of the previous fraction. Centrifugal elutriation was accomplished by suspending the tumor cells in a "Tumor Resuspension Solution" (TRS), having the following composition, based on one liter.

The suspension was elutriated using a Beckman JE-6 elutriator rotor operating at 2000 rpm in a Beckman J-2-21 centrifuge at 25[deg]C. A separation medium of Hank's Balanced Salt Solution was pumped through the system using a Cole Palmer Master Flex pump with a No. 7014 pump head. The pump control box was modified with a 10 turn potentimeter [See Anal. Biochem 98: 112-115 (1979)]. The flow rate was measured with a Brooks double-ball flow value. Hank's Balanced Salt Solution was prepared by preparing a 900 ml solution having the following composition and mixing with CaCl2.2H2O as described below. 80 g NaCI 4 g KCL 0.98 g MgS04 0.48 g Na2HP04 0.60 g KH2PO4 A 1.85 g portion of CaCl2.2H2O was made up to 100 ml solution, and mixed together with the 900 ml described above. Approximately 1 x 109 cells were injected through an in-line "Y" fitting into the mixing chamber. After a 15 minute equilibration time, cell debris was eluted at a flow rate of 9.0 x 10 ml/min. Tumor cells were eluted in 6 fractions of 50 ml each at flow rates from about 12-18 ml/min. Fractions 2-5 containing tumor cells were combined, recentrifuged (100 xg) and resuspended in 1-2 ml ofthe TRS described above. Recoveries were generally between 70-75 percent of the cells injected into the mixing chamber.

The B-16a melanoma and Lewis Lung carcinoma cells thus obtained were used to test the antimetastatic and antineoplastic activity of the methylpyrazoline compound, as described below. (1) Metastasis As indicted earlier, metastasis is a single phenomenom represented by an intricate series of events. At present, there are two "model" systems widely used in studying in vivo metastasis. The first model system involves the subcutaneous injection of tumor cells into the animal. Subcutaneous injection of tumor cells and subsequent development of a primary tumor, followed by spontaneous metastasis is considered to be "full" metastasis. Another model system involves the injection of tumor cells via the tail vein. Considering the complexity of metastasis, it is recognized that tail vein injection is an artificial and only partial model system, since it represents events occuring in the latter portion of metastasis.However, the tail vein model system is recognized as being extremely useful in standardizing experimental conditions. [See Methods in Cancer Research, Chapter VII, Academic Press, Inc., 1978.] Control (untreated) C57B1/6J mice were tested for full metastasis by the following procedure. Cell suspensions of B-16a and 3LL carcinoma cells obtained as described in A and B above, were injected (26 gauge needle, 0.2 ml) subcutaneously into the right axillary region of the male C57BL/6J mice. Varying amounts of cell suspensions in the range of 1 x 105 to 1 x 106 cells were injected. Partial metastasis experiments were conducted by injecting the control (untreated) mice with tumor cells via the tail 'vein. The animals were housed under indentical conditions of temperature, photoperiod, feeding, etc.After an observation period of from 17 to 30 days, the animals used in the full metastasis and partial metastasis were killed and the lung, liver, kidney, spleen and brain tissue was removed. The removed tissue was fixed in Bouin's solution. The number of metastatic nodules in each organ was determined using a Bausch and Lomb Stereo Zoom Microscope. Examination of the control mice for metastatic nodules indicated that 100 percent of the animals are positive for metastatic lung tumors; the incubation time to produce such metastasis was between 17-21 days and between 23-30 for the 3LL abnd B-16a tumor cells, respectively. No visible nodules were observed in the liver, kidney, spleen or brain tissue. (2) AntineoplasticActivity The antineoplastic activity was determined in vitro by measuring the DNA synthesis of both B-16a and Lewis Lung carcinoma cells, by a technique involving thymidine incorporation. Cells synthesizing DNA preparatory to cell division are characterized by their ability to incorporate thymidine. Cell proliferation, therefore, involves synthesis of DNA. If the amount of DNA synthesized by tumor cells is reduced, this is an indication that cell division, hence tumor growth, has been arrested. The antineoplastic activity was also determined by direct measurement of tumor cell growth in vitro in tissue culture. This technique involves plating or seeding a known number of tumor cells on a growth medium and determining the effect on tumor cell proliferation of the presence of the compound to be tested. Finally, the antineoplastic activity was determined in vivo by injecting mice subcutaneously with tumor cells and determining the incidence and weight of the tumor cell growth in untreated control animals and animals treated with the pyrazolone compound. The effect of 3-Methyl-1-[2-(2-napthyloxy)-ethyl]-pyrazolin-5-one on metastasis from tail vein injection of tumor cells and full metastasis from subcutaneous injection of tumor cells is shown in Examples 1 and 2 respectively.

Example 1 A 3 mg portion of 3-Methyl-1-[2-(2-naphthyloxy)-ethyl]-2-pyrazolin-5-one was suspended in 0.6 ml absolute ethyl alcohol. The suspended pyrazolone was dissolved by adjusting the suspension to a pH of 9.5 with NaOH. The final concentration of the pyrazolone was achieved by dilution of the solution with normal saline (0.9 percent NaCI).. Syngeneic C57BL/6J host mice were injected on a daily basis, with 0.02 and 0.08 mg/mouse of the methyl-pyrazol-5-one compound (subcutaneously) for a period of 3 days. On the fourth day, the pretreated mice (and control mice) were injected via the tail vein with a 5 x 104 B-16a tumor cell suspension prepared as described hereinbefore. The control mice and treated mice were housed under identical conditions of temperature, photoperiod, feeding, etc. The mice were killed 14 days after tail vein injection of the tumor cells and the lung tissue examined. The effect of injecting mice with the pyrazolone compound one hour before B-16a tumor cell injection was also determined. As seen by the data summerized in Table 1, administration of the pyrazolone compound is efficacious in drastically reducing lung tumor colonies, i.e., metastasis, at both 0.02 and 0.08 mg levels. It has been suggested that the present pyrazolone compound stimulates prostacyclin release. [See The Lancet, pp. 518-520 (March 10,1979)]. The antithrombotic activity of prostacyclin is believed to be mediated by increasing platelet levels of cyclic adenosine -3',5'-cyclic phosphoric acid (cAMP). It is also known that compounds known as phosphodiesterase inhibitors slow the breakdown of cAMP. Therefore, by slowing the breakdown of cAMP, phosphodiesterase inhibitors would be expected to potentiate the antithrombotic action of an antithrombotic agent, acting through this mechanism. Because platelets may also be involved in the mechanism of metastasis, the effect of a well-known phosphodiesterase inhibitor, theophylline, was tested for its potential synergism with the pyrazolone compound. Although the results indicate thatthe antimetastatic effect may have been enhanced by theophylline, because of the standard error involved in the experiment, synergism was not firmly established.

TABLE 1 Effect of 3-Methyl-1-[2-(2-naphthyloxy)-ethyl]-2-pyrazolin-5-one on Metastasis from Tail Vein Injected B-16a Amelanotic Melanoma Cellsa

a. 5 x 104 cells injected intravenously in 50 Microl. b. x SEM; n=6. c. Animals pretreated daily (3 days) before tumor cell injection. d. Injected 1 hour prior to tumor cells.

Example 2 The effect of administration of the pyrazolone compound for an extended period to time, on the number of metastatic lung colonies of B-16a and Lewis Lung carcinoma was determined as described below. A3 mg portion of 3-Methyl-1-[2-(2-naphthyloxy)-ethyl]-2-pyrazolin-5-one was dissolved in 0.6 ml ethyl alcohol and the solution adjusted to a pH of 9.5 with concentrated NaOH. Syngeneic C57BL/6J host mice were injected subcutaneously with a 1.8 x 105 B-16a cell suspension, prepared as described hereinbefore. Another series of syngeneic C57BL/6J host mice were injected subcutaneously with a 1 x 105 Lewis Lung carcinoma cell suspension, obtained as described hereinbefore. The day following tumor cell injection, the mice were injected subcutaneously for 28 days, with a single daily dose of either 0.01 or 0.08 mg of the pyrazolone compound. The control mice and the treated mice were housed under identical conditions of temperature photoperiod, feeding, etc. The mice injected with B-16a tumor cells were killed 25 days after injection of the tumor cells; the mice injected with Lewis Lung carcinoma cells were killed 21 days after injection of the tumor cells. Experimental data obtained on the examined lung tissue are summarized in Table 2 below.

TABLE 2 Effects of 3-Methyl-1-[2-(2-naphthyloxy)-ethyl]-2-pyrazolin-5-one on Spontaneous Metastasis from injected B-16a Amelanotic Melanomaa and Lewis Lung Carcinomab

a. 1.8 x 105 cells injected subcutaneously. b. 1 x 105 cells injected subcutaneously. c. Number of metastatic tumor colonies on bilateral lung surface; X SEM. d. Injected daily subcutaneously in 0.2 ml. As shown by the test data summarized in Table 2, the number of metastatic lung colonies of both B-16a melanoma and 3LL carcinoma are drastically reduced by administration of the pyrazolone compound. With respect to the B-16a melanoma metastasis, a dosage level of 0.01 mg appeared to be almost as effective as a dosage level of 0.08 mg. As indicated earlier, subcutaneous injection of tumor cells and subsequent development of a primary tumor, followed by spontaneous metastasis, is considered "full" metastasis. Because the procedure of Example 2 involved full metastasis, there were a lesser number of lung tumor colonies present in the control animals of Example 2 than in the control animals of Example 1, which involved development of metastasis from tail vein injection of tumor cells. However, the data in both Example 1 and Example 2 indicate that the pyrazolone compound possesses strong antimetastasis activity. The antineoplastic activity of the pyrazolone compound was determined by measuring thymidine incorporation as an indication of DNA synthesis.

Example 3 B-16a and Lewis Lung carcinoma cells were obtained as described before. The dispersed cells were diluted to a concentration of 1 x 105 cells/ml in MEM in sterile 25 ml plastic Erhlenmeyerflasks. Two MicroCi/ml of tritium-labelled thymidine ( H), having a specific activity of 50-80 Ci/mmol was added to each ml of cell suspension. The pyrazolone compound was added to a series of flasks containing the B-16a and Lewis Lung carcinoma cells, in amounts of 0.1, 1.0, 10 and 25 Microg/ml of total volume. The flasks, along with control flasks of tumor cells containing no pyrazolone compound, were then incubated at 37[deg]C in a Dubnoff Metabolic Shaker (90 oscillations/minute). At time intervals of 4 hours and 18 hours, four one ml-aliquots were removed with a pipette and placed in 1.5 conical polypropylene tubes. The cells were centrifuged into pellets by spinning in a Brinkman "Mini-Centrifuge" for 8 minutes (10,000 xg). The supernatant fraction was removed and discarded into a radioactive-waste container. A 1.0 ml portion of cold trichloroacetic acid (6 percent w/v) was added to each tube to precipitate proteins present, including DNA and RNA. The tubes were capped and vortexed to break the cells apart by centrifuging as described above. The pellets obtained contain the acid-insoluble fraction with the DNA. The supernatant, containing the acid soluble portion was discarded.The inside of each tube was swabbed with a cotton-tip swab to remove excess acid-soluble radioactivity.The pelletes were dissolved by adding 50 Microl of a tissue solubilizer, commercially available from Amersham Corporation, Del., Arlington Heights, Illinois, under the trade designation NCS, to each tube. The tubes were capped and incubated at approximately 50[deg]C for about 2 hours or until the pellets dissolved. The tips of the tubes containing dissolved pellets were cut and the contents transferred to scintillation vials. Three ml of a scintillation counting fluid mixed with xylene in a 2:1 ratio was added to each scintillation vial. Each vial was capped and vortexed and the amount of radiolabelled thymidine'incorporated by DNA synthesis determined. The counts per minutes were corrected by a Searle PDS computer using quench-correction analysis and reported as percent control. The experimental results obtained are shown in Figure 1 below. At each pyrazolone concentration level, the amount of DNA synthesized is based on 100 percent level for the control sample. As shown in Figure 1, the pyrazolone compound produced a concentration-dependent decrease in DNA synthesis, as determined by H-thymidine incorporation. This decrease in DNA synthesis indicates that the pyrazolone compound possesses antineoplastic activity. Verification ofthymidine incorporation into DNAwas performed as described in Biochem and Biophysical Research Communications, Vol. 87, No. 3, pages 795-801 (1979). Further evidence of the antineoplastic activity of the pyrazolone compound was obtained by direct measurement of tumor cell proliferation in tissue culture.

Example 4 B-16a melanoma cells, obtained as described before, were seeded on 60 mm gridded petri dishes, at a density of 3 x 104 cells per plate. The cells were cultured in a medium of MEM, Hank's Basic Salt Solution and 10 percent fetal calf serum, commercially available from Microbiological Associates, Walkersville, Maryland. After 24 hour incubation at 37[deg]C, the cell counts were performed by visual counting in an inverted microscope. Medium was changed and replaced with the above medium and pyrazolone in a concentration range varying from 0.1 to 25 Microg/ml. Controls received medium change alone. Thereafter the medium which contained pyrazolone was replaced every other day. After 8 days, cell counts were determined as described above and cell viabilities determined by the vital dye exclusive method referred to earlier. Experimental results obtained are shown in Figure 2 below. The data is presented as mean cell number standard error, of six replicate plates. The number above each bar indicates cell viability, based on 100 percent cell viability. The data indicates that the pryazolone compound inhibited tumor cell proliferation over the same dose range that the compound inhibited DNA synthesis. The viability index, which ranged between 96 0.9 and 94 0.4 indicates that the antineoplastic activity of the pyrazolone compound was not due to cytotoxicity of the compound. Another experiment was conducted, in vivo, to measure antineoplastic effects of the pyrazolone compound.

Example 5 A3 mg portion of3-Methyl-1-[2-(2-naphthyloxy)ethyl]-2-pyrazolin-5-onewas dissolved in 0.6 ml ethyl alcohol and the solution adjuted to a pH of 9.5 with concentrated NaOH. Syngeneic C57BL/6J host mice were subcutaneously injected with 1 x 105 Lewis Lung carcinoma cells (0.2 ml) into the axillary region. After a period of 24 hours, the pyrazolone compound was administered daily for 21 days. The effect of administration of theophylline with the pyrazolone compound was also tested. During the period the mice were housed under identical conditions of temperature, photoperiod, feeding, etc. The mice were killed 22 days after injection of the tumor cells and the mice examined by gross necropsy for the presence of subcutaneous tumors. Tumors present were removed and weighed on an anlytical balance. Experimental data obtained are summarized in Table 3 below.

TABLE 3 Effects of 3-Methyl-1-[2-(2-naphthyloxy)-ethyl]-2-pyrazolin-5-one on Tumor Incidence and Final Weight in the Lewis Lung Carcinomaa

a. 105 viable 3LL cells were injected subcutaneously (0.2 ml) into the axillary region. Drug administration began 24 hours later. b. Injected dialy subcutaneously (flank area) in 0.2 ml. c. Injected daily intraperitoneally in 0.4 ml. As shown by the test data in Table 3, both the incidence and weight of the Lewis Lung carcinoma tumor was reduced by subcutaneous administration of the pyrazolone compound, demonstrating antineoplastic activity and corraborating the in vitro data of Examples 3 and 4. Theophylline appeared to enhance the effect of the pyrazolone compound, perhaps by increasing the amount of cAMP.

Claims (1)

1. CLAIM

   1. 3-Methyl-1-[2-(2-naphthyloxy)-ethyl]-2-pyrazolin-5-one for use in combating metastasis and neoplastic growth in human and non-human animals.