WO1993008120A1

WO1993008120A1 - 2-aminopropan-1,3-diol chemotherapeutic agents

Info

Publication number: WO1993008120A1
Application number: PCT/US1992/008910
Authority: WO
Inventors: Jack B. Jiang
Original assignee: Sphinx Pharmaceuticals Corporation
Priority date: 1991-10-21
Filing date: 1992-10-19
Publication date: 1993-04-29
Also published as: JPH07501521A; EP0609356A1; CA2120234A1; AU2880192A; EP0609356A4

Abstract

The present invention provides a pharmaceutical system adapted to inhibit the growth of a mammalian cancer tumor or cell characterized by a chemotherapeutic agent selected from adriamycin and cisplatin in conjunction with an effective amount of a potentiating agent comprising a compound having formula (I), wherein R is C5-C20 alkyl, alkenyl or alkynyl. The present invention further provides a method of inhibiting the in vitro growth of a mammalian cancer tumor or cell comprising administering to the tumor or cell an amount of a chemotherapy agent selected from adriamycin and cisplatin effective to inhibit growth of the tumor or cell; and administering to the tumor or cell an amount of a potentiating agent comprising a compound having formula (II) wherein R is C5-C20 alkyl, alkenyl or alkynyl, in an amount effective to induce enhanced growth inhibition produced by the chemotherapy agent.

Description

2-AMINOPROPA -l,3-DIOL CHEMOTHERAPEUTIC AGENTS

Field of the invention

The present invention relates to the field of chemotherapy for mammalian tumors. More particularly, the present invention relates to 2-amino-propan-l,3-diol derivatives which act as potentiators of mammalian cancer chemotherapeutical agents.

Background of the Invention

Chemical modification is a concept in cancer therapy in which the state of tumor cells or normal tissue is modified such that a therapeutic gain can be achieved using conventional therapeutic modalities. Chemical modification refers to the use of agents that potentiate by chemical or physical means known cytotoxic agents, i.e. radiation or chemotherapy. There are a number of existing therapies directed to modification. For example, 2-nitroimidazole compounds act as chemosensitizers for hypoxic cells. A number of other classes of compounds are non-hypoxic cell sensitizers. For example, halogenated pyrimidines were designed as thymidine analogs to be incorporated into the DNA of cycling cells to make them more sensitive to irradiation. In addition, preliminary data indicates that halogenated pyrimidines might be effective chemosentizers for melphalan, doxorubicin, cisplatin, and neocarcinostatin. The modulation of a biosynthetic pathway, is another method for modulating chemotherapy. For example, L- buthionine sulfoximine (L-BSO) interferes with glutathione (GSH) biosynthesis. Protein kinase C (PKC) is a family of calcium stimulatable and phospholipid-dependent serine/threonine- specific protein kinases which play an important role in cellular growth control, regulation, and differentiation. Protein kinase C is also fundamental to the processes involved in tumorigenicity, since it is the major high-affinity receptor for several classes of tumor promoters as well as for endogenous cellular diacylglycerols. These tumor promoters also stimulate protein kinase C catalysis. Castagna et al. (1982) J. Biol. Chem. 257: 7847 reported direct activation of protein kinase C by tumor-promoting phorbol esters. The mechanisms of protein kinase C action have been described in U.S. Patent 4,816,450 issued March 28, 1989 to Bell et al. , the disclosures of which are specifically incorporated as if fully set forth herein. Protein kinase C is activated by diacylglycerol (DAG) , a neutral lipid, and when activated will transfer the γ-phosphate. of MgATP to a serine or threonine residue on a substrate protein.

Protein kinase inhibitors such as 3-hexadecyl- mercapto-2-methoxy-methyl-propyl-l-phosphocholine (BM41440) , 1- octadecyl-2-methyl-sn-glycero-3-phosphocholine (ET-18-OCH₃) , quercetin, tamoxifen, staurosporine, and ilmofosin have been found useful as potentiators of the antitumor activity of chemotherapeutic agents. For example, these inhibitors have been reported to potentiate the antitumor activity of the chemotherapeutic agent cisplatin both in vitro and in vivo (Grunicke et al., (1989) Adv. Enzym. Regul. 2___\ 201; and German Offenlegungsschrift DE 3827974).

German Offenlegungsschrift DE 3827974 Al discloses therapeutic preparations comprising a protein kinase C inhibitor such as BM41440, ET-18-OCH₃, quercetin, tamoxifen, staurosporine, and ilmofosin, in combination with a lipid, a lipid analogue, a cytostatic agent or phospholipase inhibitor useful for cancer therapy. Mammalian cancers and tumors are life-threatening diseases for which there are few definitive treatments at the present time. Consequently, there is a great need for treatments for mammalian cancers and tumors. There is also a need for chemotherapeutic potentiators for use in conjunction with established chemotherapy agents. Obtainment of these and other objects of the invention are fully disclosed hereinbelow. Summary of the Invention

The present invention provides methods of inhibiting the growth of a mammalian cancer tumor or cell comprising contacting the cell with a chemotherapeutic agent in conjunction with contacting the tumor or cell with a potentiating agent comprising a compound having the formula

O H N H₂ R C H C H C H₂ OH

Formula I wherein R is C₅-C₂₀ alkyl, alkenyl or alkynyl, the combination of the amount of the chemotherapeutic agent and the amount of the potentiating agent being effective to inhibit growth of the tumor or cell.

In accordance with the present invention, methods of increasing the effectiveness of a chemotherapy agent towards a cell exposed to such chemotherapy agent comprising exposing said cell to an effective amount of a potentiating agent comprising a compound of Formula I as defined hereinabove are also provided.

In other embodiments of the present invention, methods of inhibiting the growth of a mammalian cancer tumor or cell comprising administering to the tumor or cell an amount of a chemotherapy agent effective to inhibit growth of the tumor or cell and administering to the tumor or cell an amount of a potentiating agent comprising a compound of Formula I as defined hereinabove effective to increase the amount of growth inhibition produced by the chemotherapy agent are provided.

Methods of treating mammalian tumors comprising administering to a mammal having a tumor an amount of a chemotherapy agent effective to inhibit growth of said tumor and administering to said mammal an amount of a potentiating agent comprising a compound of Formula I as defined hereinabove effective to increase the amount of growth inhibition produced by said chemotherapy agent are also provided.

In addition, the present invention provides compounds of Formula I wherein R is C₅-C₂₀ alkynyl that are useful as potentiating chemotherapeutic agents.

Further aspects of the present invention provide a pharmaceutical system adapted to inhibit the growth of a mammalian cancer tumor or cell characterized by a chemotherapeutic agent selected from adriamycin and cisplatin in conjunction with an effective amount of a potentiating agent comprising a compound of Formula I as described hereinabove. In some embodiments of the pharmaceutical systems of the present invention, the chemotherapeutic agent is packaged with, but separately to, the potentiating agent, and the chemotherapeutic agent is adapted to be administered prior to the administration of the potentiating agent.

The present invention also provides the use in the manufacture of a pharmaceutical system for inhibiting the growth of a mammalian cancer tumor or cell of a chemotherapeutic agent selected from adriamycin and cisplatin and a potentiating agent comprising a compound having Formula I as described hereinabove. The chemotherapeutic agent may be packaged with, but separately to, the potentiating agent of Formula I, and the chemotherapeutic agent adapted to be administered prior to the administration of the potentiating agent.

The present invention further provides the use of a compound of Formula I as described hereinabove in the manufacture of a medicament for potentiation of the chemotherapeutic effects of adriamycin or cis-platin in the treatment of mammalian cancer or tumors.

This invention is more particularly described in the appended claims and is described in its preferred embodiments in the following description.

Brief Description of the Drawings Figure 1 is a graphical representation of the effect of threo-2-amino-l,3-octadecanediol hydrochloride on tumors subsequently treated with adriamycin.

Figure 2 is a graphical representation of the effect of threo-2-amino-l,3-octadecanediol hydrochloride on tumors subsequently treated with cisplatin. Detailed Description of the Invention

In accordance with the present invention, growth of a mammalian cancer tumor or cell is inhibited by contacting the tumor or cell with a chemotherapeutic agent in conjunction with contacting the tumor or cell with a potentiating agent comprising a compound having the formula

Formula I wherein R is C₅-C₂₀ alkyl, alkenyl or alkynyl are disclosed. More preferably, R is C₁₀-C₂₀ alkyl or alkenyl. Most preferably, R is C₁₄-C_l8 alkyl. As used herein, alkyl, alkenyl and alkynyl substituents include straight chain, branched and cyclic moieties, preferably straight chain species.

The chemotherapeutic agent and the potentiating agent are contacted with the tumor or cell in amounts such that the combination of the amount of the chemotherapeutic agent and the amount of the potentiating agent is effective to inhibit growth of the tumor or cell. The amount of agents effective to inhibit growth mammalian cancer tumors and/or cancerous cells is the amount of chemotherapeutic agent and potentiating agent which, in combination, decreases the rate of growth of a cancer tumor or cells, prevents further growth of a cancer tumor or cells, decreases the size of existing cancer tumors or cancerous cells, or eliminates the cancer tumor or cells altogether.

Inhibition of growth, in the context of the present invention, refers to inhibiting tumorigenic or undesirable growth, i.e. growth which is uncharacteristic of normal cells. Inhibition of growth is characterized by the decrease in the rate of growth of a tumor and/or cancerous cells, inhibition of further growth of a tumor and/or cancerous cells, decrease in the size of existing tumors and/or cancerous cells, or elimination of the tumor and/or cancerous cells altogether. Inhibition of growth also includes inhibition of cell growth and division, i.e. the proliferation of cells.

Generally, inhibition of growth may be detected by comparing tumor size before and after treatment. Comparison of healthy and tumorigenic mammals and/or cells before and after treatment may also indicate the degree of inhibition of cell growth. Inhibition of growth may also be detected by examination of cell cultures before and after treatment to detect the degree of cell proliferation and cell death. Other methods for the detection of inhibition of cell growth known to those skilled in the art are also encompassed by the present invention.

Chemotherapeutic agents and potentiating agents are administered to tumors or cells in conjunction with one another. Administration of the chemotherapeutic agent and the potentiating agent in conjunction with one another refers to administeringthe chemotherapeutic agent to a mammal, typically a human patient, to treat cancer cells or tumors prior to or after administration of the potentiating agent, or at substantially the same time as administration of the potentiating agent. Particular administration methods will vary with the age, health and weight of recipient, the nature and extent of symptoms, kind of concurrent treatment, frequency of treatment, and the effect desired. In general, the chemotherapy agent and potentiating agent may be administered sequentially or together in a single dose or application. For example, the chemotherapeutic agent may be administered prior to or subsequent to the administration of the potentiating agent. The chemotherapeutic agent and the potentiating agent may also be administered at substantially the same time, in a single application, or in separate applications administered within a short period of time of each other. In preferred embodiments of the present invention, the potentiating agent is - 1 - administered from about 90 to about 15 minutes prior to the administration of the chemotherapeutic agent. In more preferred embodiments, potentiating agent may be administered from about 20 to about 70 minutes prior to administration of the chemotherapeutic agent. Most preferably, the potentiating agent is administered from about 25 to about 35 minutes prior to administration of the chemotherapeutic agent:

Research using a mouse tumor model has indicated that administration of the potentiating agent from about 90 to about 15 minutes prior to administration of the chemotherapeutic agent greatly increases the tumor and/or cell growth inhibition produced by the chemotherapeutic agent. Optimal times and order of administration of the potentiating agent and the chemotherapeutic agent may vary according to the type of cell or species of mammal treated. The desired order and timing may be determined by comparison of the results obtained by administering the potentiating agent and the chemotherapeutic agent at various times and orders and selecting the combination producing the desired effect. Other aspects of the present invention provide methods of increasing the effectiveness of, or "potentiating", a chemotherapeutic agent towards a cell or tumor exposed to such chemotherapeutic agent which comprise exposing the cell or tumor to an effective amount of a potentiating agent comprising a compound of Formula I wherein R is C₅-C₂₀ alkyl, alkenyl or alkynyl. More preferably, R is C₁₀-C₂₀ alkyl or alkenyl. Most preferably, R is C₁₄-C₁₈ alkyl. Potentiate, as used herein, is intended to refer to the function of causing or increasing effectiveness of a chemotherapy agent. Hence, potentiating agents of the present invention which potentiate chemotherapeutic agents make such agents effective, or more effective in treating cancer or uncontrolled cell growth characteristic of cancer.

Chemotherapeutic agents act in a number of ways to treat cancer and tumorigenicity. Chemotherapeutic agents may, for example, target intermediary metabolism or DNA function. The ultimate goal of most chemotherapeutic agents is to kill cancer cells or reduce the proliferation of cancerous cells. Therefore, the effectiveness of a chemotherapeutic agent is enhanced when the ability of the chemotherapeutic agent to kill or reduce proliferation of cancerous cells is increased, regardless of the mechanism by which the eradication of cancerous cells and/or tumors is achieved. Persons skilled in the art are aware of methods of evaluating effectiveness of agents. For example, as described above, effectiveness may be evaluated by comparison of normal and cancerous cell and/or tumor growth at different times after treatment of cancerous cells or tumors, or by comparison of cell and/or tumor growth before and after administration of chemotherapeutic and potentiating agents. An effective measure of the increase in the amount of growth inhibition attributed to a potentiating agent is achieved by comparing the inhibition of cell and/or tumor growth effected by a chemotherapeutic agent alone, and cell and/or tumor growth inhibition of a chemotherapeutic agent in the presence of potentiating agent of the present invention.

Further aspects of the present invention provide methods of inhibiting growth of mammalian tumor cells which comprise administering to the cell an amount of a chemotherapy agent effective to inhibit growth of the cell and administering to the cell an amount of a potentiating agent comprising a compound of Formula I wherein R is C₅-C₂₀ alkyl, alkenyl or alkynyl effective to increase the amount of growth inhibition produced by the chemotherapy agent. More preferably, R is C₁₀- C₂₀ alkyl or alkenyl. Most preferably, R is C₁₄-C₁₈ alkyl.

In addition, the present invention provides methods of treating mammalian tumor which comprise administering to a mammal having a tumor an amount of a chemotherapy agent effective to inhibit growth of the tumor and administering to the mammal an amount of a potentiating agent comprising a compound of Formula I as defined hereinabove effective to increase the amount of growth inhibition produced by the chemotherapy agent. Finally, the present invention provides a composition for potentiating chemotherapeutic agents which comprises a compound of Formula I wherein R is C₅-C₂₀ alkynyl.

It was surprisingly found that the methods and compositions of the present invention were effective to potentiate chemotherapeutic agents. While potentiating agents described herein exhibit minimal effect on the inhibition of tumors when administered alone, significant tumor inhibition is observed when potentiating agents are administered in accordance with methods of the present invention. The administration of a potentiating agent in conjunction with a chemotherapeutic agent in accordance with the methods of the invention produced a synergistic inhibition of tumor growth as compared with the inhibition of tumor growth produced by administration of the chemotherapy agent or potentiating agent alone. As a result of the synergistic effect of a potentiating agent administered in conjunction with a chemotherapy in accordance with methods of the present invention, lower dosages of chemotherapeutic agents may be used in the course of treatment of cancer and tumorigenic conditions. Alternatively, the conventional doses could be administered in conjunction with the potentiating agent for a shorter period of time. Thus, many of the deleterious side effects of cancer therapy such as myocardial toxicity, myelosuppression, nephrotoxicity and thrombosis might be avoided by using lower dosages of chemotherapeutic agents. Without wishing to be bound to any theory or mode of action, Applicants conjecture that the effectiveness of the potentiating compounds of the present invention in increasing the effectiveness of chemotherapeutic agents is due to their protein kinase C inhibitory activity. Protein kinase C inhibitory activity of some of the potentiating agents useful in the methods of the present invention is disclosed in U.S. patent 4,816,450 issued March 28, 1989. Cancer may be characterized by uncontrolled cellular growth or tumorigenicity. Inhibition of growth of mammalian tumor cells is directed to inhibition of uncontrolled cellular growth associated with cancer and tumorigenicity. Protein kinase C is directly involved in cellular growth control and is believed to be involved in tumor formation. Protein kinase C is commonly activated by diacylglycerols (DAGs) , but protein kinase C is also the major, if not exclusive, intracellular receptor of phorbol esters which are very potent tumor promoters. Phorbol esters, such as phorbol myristate acetate (PMA) , have complex effects on cells including effects on membrane function, mitogenesis, differentiation, and gene expression. Phorbol esters and other tumor promoters bind to and activate protein kinase C.

In addition, studies on oncogene ras transformed cells have shown protein kinase C activation to be concomitant with elevation of DAG. Thus, protein kinase C may mediate the actions of certain oncogenes, such as ras, which cause intracellular increases in DAG and concomitant increases in protein kinase C.

Several studies have shown increased expression of protein kinase C in certain tumor types such as breast and lung carcinomas. Activated protein kinase C has also been detected in human colon carcinomas although increased expression on the gene level was not seen.

As used herein, chemotherapeutic agent(s) refer to chemical compound(s) capable of inhibiting growth of mammalian tumor cells and/or mammalia?ι tumors or other useful treatment of mammalian tumors, cancer or precancerous conditions. Cisplatin (σis-diamminedichloroplatinum, also sometimes known as cis-platinum) , adriamycin, mechlorethamine, cyclophosphamide, chlorambucil, BCNU, 5-fluorouracil, cytosine arabinoside, 6-thioguanine, VP-16, vinca alkaloids, mitomycin C, bleomycin, actinomycin D, mitoxantrone and mAMSA are examples of chemotherapeutic agents useful in the methods of the present invention. The foregoing chemotherapeutic agents are well known and are available commercially through pharmaceutical suppliers. Preferred chemotherapy agents include adriamycin and cisplatin. Generally such agents have some cancer inhibitory effect in the absence of potentiating agents of the present invention.

While the full range of oncologic diseases is not yet known and while it is likely that the present therapeutic methods will have utility for large numbers of these, the present methods are expected to be useful or particularly useful for treating those diseases which have proven to be susceptible or amenable to treatment by chemotherapy. For example, adriamycin has been used successfully to produce regression in disseminated neoplastic conditions such as acute lymphoblastic leukemia, acute myeloblastic leukemia, Wilms' tumor, neuroblastoma, soft tissue and bone sarcomas, breast carcinoma and ovarian carcinoma. Cisplatin may be used for the treatment of metastatic testicular tumors and metastatic ovarian tumors. In addition, cisplatin may be used for the treatment of advanced bladder cancer. The above list is not exhaustive and is not intended in any way to limit the types of tumors or conditions that may be usefully treated by the methods of the invention. Pharmaceutically acceptable salts of the potentiating agents of the invention are also useful in the present invention. Such pharmaceutically acceptable salts include salts of hydrochloric acid, hydrobromic acid, fumaric acid, oxalic acid, maleic acid, succinic acid, pamoic acid, sulfuric acid and phosphoric acid.

Cells exposed to chemotherapeutic or potentiating agents are contacted with such agents. The potentiating agent and chemotherapeutic agents useful in methods of the invention may be administered by any method that produces contact of the compound or therapeutic agent with its site of action in the body of a mammal including but not limited to oral, intravenous, and intraparenteral administration. The potentiating agents of the invention may be administered singly, or in combination with other potentiating agents, or other therapies, such as radiation treatment. The potentiating agents are preferably administered with a pharmaceutically acceptable carrier or diluent selected on the basis of the selected route of administration and standard pharmaceutical practice.

Chemotherapeutic agents useful in the methods of the present invention are administered in formulations and at doses according to established protocols known to those skilled in the art. For example, for the treatment of metastatic ovarian tumors 50mg/m² cisplatin may be administered intravenously once every three weeks m conjunction with 50mg/m 2 of adriamycin intravenously once every three weeks. Cisplatin may also be administered intravenously in lOOmg/m doses once every four weeks. Adriamycin may be administered intravenously in 60-75 mg/m² doses at 21 day intervals. One method of administration is by intravenous infusion in freely running sodium chloride or 5% dextrose. 40-50mg/kg of cyclophosphamide may be administered intravenously in divided doses over a 2-5 day period, or 10-15mg/kg may be administered every 7-10 days. 3-5 mg/kg of cyclophosphamide may be administered intravenously twice weekly.

The potentiating agents are administered to mammals, preferably humans, in therapeutically effective amounts or concentrations which are effective to increase the effectiveness or therapeutic action of the chemotherapy agent. The dosage administered in any particular instance will depend upon factors such as the pharmacodynamic characteristics of the particular potentiating agent, and its mode and route of administration; age, health, and weight of the recipient; nature and extent of symptoms; kind of concurrent treatment, frequency of treatment, and the effect desired. It is contemplated that the dosage of the potentiating agents will be in the range of from about 5 to about 400 mg per kg of body weight, preferably from about 10 to about 200 mg per kg body weight administered in conjunction with the chemotherapeutic agent.

The potentiating agents useful in the methods of the present invention are disclosed in U.S. patent 4,816,450 issued

March 28, 1989 to Bell et al. , the entire teachings of which are herein incorporated by reference. The potentiating agents may be naturally occurring or synthetically occurring. In particular, the potentiating agents of Formula I as described hereinabove having alkyl and alkenyl substituents are disclosed in U.S. patent 4,816,450 and can be prepared by the methods disclosed therein or by making obvious and appropriate substitutions of starting materials. Potentiating agents of formula I having alkynyl substituents may be prepared by methods known in the art, or by the methods disclosed in U.S. patent 4,816,450 and making obvious and appropriate substitutions of starting materials. The potentiating agents of the present invention are also commercially available; for instance, threo-2-amino-l,3-octadecanediol hydrochloride is available from Sigma Chemical Company, St. Louis, MO. The potentiating agents may also be conveniently synthesized from an N-protected serine, such as an N-phenylsulfonyl protected serine through reaction with a suitable saturated or unsaturated Grignard reagent. For example a suitable bromo- or chloro-substituted alkyl, alkenyl or alkynyl compound is reacted with magnesium to form the Grignard reagent which is then reacted with the N-protected serine to form the N- protected 2-animo-l,3-propandiol derivative. The N-protecting group is then removed to form the potentiating agent.

The potentiating agents may be formulated as medicaments and administered orally in solid dosage forms, such as capsules, tablets, and powders, or in liquid dosage forms, such as elixirs, syrups, and suspensions. They may also be formulated and administered parenterally in sterile liquid dosage forms. The potentiating agents may be formulated into dosage forms according to standard practices in the field of pharmaceutical preparations. See Remington 's Pharmaceutical Sciences , A. Osol, Mack Publishing Company, Easton, Pennsylvania, a standard reference text in this field.

For example, the potentiating agents may be mixed with powdered carriers, such as lactose, sucrose, mannitol, starch, cellulose derivatives, magnesium stearate, and stearic acid for insertion into gelatin capsules, or for forming into tablets. Both tablets and capsules may be manufactured as sustained release products for continuous release of medication over a period of hours. Compressed tablets can be sugar coated or film coated to mask any unpleasant taste and protect the tablet from the atmosphere or enteric coated for selective disintegration in the gastrointestinal tract.

Liquid dosage forms for oral administration may contain coloring and flavoring to increase patient acceptance, in addition to a pharmaceutically acceptable diluent such as water, buffer or saline solution. Forparenteral administration, thepotentiatingagents may be mixed with a suitable carrier or diluent such as water, a oil, saline solution, aqueous dextrose (glucose) , and related sugar solutions, and glycols such as propylene glycol or polyethylene glycols. Solutions for parenteral administration contain preferably a water soluble salt of the potentiating agent. Stabilizing agents, antioxidizing agents and preservatives may also be added. Suitable antioxidizing agents include sodium bisulfite, sodium sulfite, and ascorbic acid, citric acid and its salts, and sodium EDTA. Suitable preservatives include benzalkonium chloride, methyl- or propyl- paraben, and chlorbutanol.

For the pharmaceutical systems of the present invention, the chemotherapy agent can be packaged with, but seaprately to, the potentiating agent. For example, the chemotherapy agent and potentiating agent can be packaged in the same container when simultaneous administration of the chemotherapy agent and potentiating agent is desired. If administration of the chemotherapy agent and potentiating agent at different times is desired, they can be packaged together but in separate containers. Packaging the chemotherapy agent and potentiating together but in separate containers is also desirable if the chemotherapy agent and potentiating agent are to be administered by different routes. The pharmaceutical system can also be supplied with instructions for administration of the chemotherapy agent and potentiating agent in accordance with the present invention. The following are specific examples which are illustrative of the present invention and are not intended to limit the scope of the invention.

Example 1 Tumor Regrowth Delay - Adriamycin and threo-2-amino- 1,3-octadecanediol hydrochloride

This assay is performed with the 16C mouse mammary carcinoma transplanted into C3H mice according to the method in Corbett, T.H. et al . , Cancer Test Rep. j62.: 1471 (1978). Briefly, for tumor inoculation, cells are prepared from a 16C tumor previously removed from a C3H mouse. 2x10 cells are injected in a volume of 0.02 ml phosphate buffered saline (PBS) intramuscularly in the left hind limb to form an experimental tumor which is then monitored to determine the effects of the chemotherapy agent and/or potentiating agent. Tumor size is measured 3 to 5 times a week by passing the tumor bearing leg through a plastic rod with increasing diameter holes. The smallest hole the tumor bearing leg will pass through is determined and converted to a tumor weight from a previously established calibration curve. Tumors of a narrow range of sizes are selected at the start of the experiment and assigned to the various treatment groups. After treatment measurements are made and the number of days for the tumors to reach 4 or 5 times the starting size is recorded as a function of the treatment. Mice having experimental tumors were divided into groups containing 5 mice each and treated as follows: (1) control (vehicle, intraperitoneally [i.p]; (2) adriamycin alone (lOmg/kg, i.p) ; (3) threo-2-amino-l,3-octadecanediol hydrochloride (Sigma Chemical Company, St. Louis, MO, 40mg/kg, i.p.) 3 hours prior to administration of adriamycin (lOmg/kg, i.p.); (4) threo-2-amino-1,3-octadecanediol hydrochloride (40mg/kg, i.p.) 1 hour prior to administration of adriamycin (lOmg/kg, i.p.); (5) threo-2-amino-l,3-octadecanediol hydrochloride (40mg/kg, i-P-) 30 minutes prior to administration of adriamycin (lOmg/kg, i.p.). The results of administration of adriamycin in conjunction with threo-2-amino- 1,3-octadecanediol are shown in Figure 1. Control results are represented by open circles. Closed triangles represent results for the group treated with adriamycin alone. Results of the group treated with threo-2-amino-l,3-octadecanediol hydrochloride three hours prior to administration of adriamycin is represented by closed squares. Closed circles represent data from the group treated with threo-2-amino-l,3- octadecanediol hydrochloride one hour prior to administration of adriamycin. Open triangles represent data from the group treated with threo-2-amino-l,3-octadecanediol hydrochloride thirty minutes prior to administration of adriamycin. Previous studies showed that treatment with threo-2-amino-l,3- octadecanediol hydrochloride alone had no effect on tumor growth, producing the same result as the control (open circle) . By day 4, tumors of control mice had grown to the weight of l.Og (based on externally measured tumor size) . Tumors treated with adriamycin alone showed an initial decrease in the rate of tumor growth, however, by day 14 tumors had grown to greater than 0.8g. Tumors treated with threo-2-amino-l,3- octadecanediol hydrochloride 3 hours before treatment with adriamycin showed substantially decreased tumor growth and by day 6 tumor size had reduced to below the limit of palpation (O.lg). Tumors treated with threo-2-amino-l,3-octadecanediol hydrochloride 1 hours before treatment with adriamycin exhibited little or no growth and by day 4 the size of tumors was below the limit of palpation. Tumors treated with threo-2- amino-l,3-octadecanediol hydrochloride 30 minutes before treatment with adriamycin showed little.or no tumor growth and tumor size was reduced to below the limits of palpation by day 5. For all mice receiving threo-2-amino-l,3- octadecanediol hydrochloride, tumor weight was below O.lg (limit of palpation) by day 6 and beyond.

The fourteen day survival for mice treated with threo- 2-amino-l,3-octadecanediolhydrochloride/adriamycin is shownin Table 1. Table l Group Survival #\Total %Deaths

(1) Control 5\5 0

(2) Adriamycin alone 5\5 0 (3) 3 hr pretreatment 0\5 100

(4) 1 hr pretreatment 3\5 40

(5) 30 in pretreatment 5\5 0

100% survival rates were exhibited for control mice and mice treated with adriamycin alone, or treatment of threo- 2-amino-l,3-octadecanediol hydrochloride 30 minutes prior to administration of adriamycin. By day 14 40% of mice pretreated 1 hour before administration of adriamycin and 100% of mice pretreated 3 hours before administration of adriamycin died. By day 16 all remaining threo-2-amino-l,3-octadecanediol hydrochloride treated mice appeared moribund and were terminated.

Example 2 Tumor Regrowth Delay - Cisplatin and threo-2-amino- 1,3-octadecanediol hydrochloride

The tumor regrowth delay assay was performed according to Example 1 except that cisplatin (5 mg/kg or 10 mg/kg, i.p.) was administered to the mice instead of adriamycin, and the dose of the potentiating agent threo-2-amino-l,3-octadecanediol hydrochloride was 20 mg/kg, i.p.. 2-amino-l,3-octadecanediol hydrochloride was administered to the mice 30 minutes prior to administration of cisplatin (also known as cisplatinum and shown as such in Figure 2) .

Figure 2 shows a graphical representation of the effect of threo-2-amino-l,3-octadecanediol hydrochloride on tumors subsequently treated with cisplatin. Vehicle control results are represented by closed circles. Results of administration of threo-2-amino-l, 3-octadecanediol hydrochloride are represented by open circles. Results of administration of cisplatin (5 mg/kg) alone are represented by open squares. Results of administration of cisplatin (5 mg/kg) and threo-2-amino-l,3-octadecanediol hydrochloride (20 mg/kg) are represented by closed squares. Open triangles represent the data from the group of mice treated with cisplatin (10 mg/kg) alone. Closed triangles represent the data from the group of mice treated with cisplatin (10 mg/kg) and threo-2- amino-1,3-octadecanediol hydrochloride (20 mg/kg). As shown in Figure 2, control tumors increased in size to a weight of about 1.5 grams after 5 days. Treatment of mice with 20 mg/kg threo-2-amino-l,3-octadecanediol hydrochloride alone produced similar results. Treatment of mice with 20 mg/kg threo-2-amino-l,3-octadecanediol hydrochloride thirty minutes prior to administration of 5 mg/kg cisplatin inhibited tumor growth by substantially the same amount as 10 mg/kg of cisplatin administered-alone. Tumor size remained stable until day 5 when it began to increase. Even more dramatically, tumors in mice treated with 20 mg/kg threo-2-amino-l,3- octadecanediol hydrochloride thirty minutes prior to administration of 10 mg/kg cisplatin showed little or no tumor growth and tumor size was reduced to below the limits of palpation by day 4. Tumors remained below the limits of palpation until day 15 when tumor size began to increase. Thus, threo-2-amino-l,3-octadecanediol hydrochloride substantially potentiates the anticancer effect of cisplatin in the 16C mouse mammary carcinoma model.

Claims

What is claimed is:

1. A pharmaceutical system adapted to inhibit the growth of a mammalian cancer tumor or cell characterized by a chemotherapeutic agent selected from adriamycin and cisplatin in conjunction with an effective amount of a potentiating agent comprising a compound having the formula:

wherein R is C₅-C₂₀ alkyl, alkenyl or alkynyl.

2. A system according to claim 1 characterized in that said chemotherapeutic agent is packaged with, but separately to, said potentiating agent, and in that the chemotherapeutic agent is adapted to be administered prior to the administration of said potentiating agent.

3. A system according to either preceding claims wherein R is C₁₀-C₂₀ alkyl or alkenyl.

4. A system according to any preceding claim wherein R is C₁₄-C₁₈ alkyl.

5. A system according to any preceding claim wherein said potentiating agent is threo-2-amino-l, 3-octadecanediol hydrochloride.

6. The use in the manufacture of a pharmaceutical system for inhibiting the growth of a mammalian cancer tumor or cell of a chemotherapeutic agent selected from adriamycin and cisplatin and a potentiating agent comprising a compound having the formula of:

wherein R is C₅-C₂₀ alkyl, alkenyl or alkenyl.

7. The use according to claim 6 characterized in that said chemotherapeutic agent is packaged with, but separately to, said potentiating agent, and in that the chemotherapeutic agent is adapted to be administered prior to the administration of said potentiating agent.

8. The use of a compound having the formula

wherein R is C₅-C₂₀ alkyl, alkenyl or alkynyl in the manufacture of a medicament for potentiation of the chemotherapeutic effects of adriamycin or cis-platin in the treatment of mammalian cancer or tumors.

9. The use according to claims 6, 7 or 8 wherein R is C₁₀-C₂₀ alkyl or alkenyl.

10. The use according to any of claims 6 to 9 wherein

R is C_l4-C₁₈ alkyl.

11. The use according to any of claims 6 to 10 wherein said potentiating agent is threo-2-amino-l, 3- octadecanediol hydrochloride.

12. A method of inhibiting the in vitro growth of a mammalian cancer tumor or cell comprising administering to said tumor or cell an amount of a chemotherapy agent selected from adriamycin and cisplatin effective to inhibit growth of said tumor or cell; and administering to said tumor or cell an amount of a potentiating agent comprising a compound having the formula:

wherein R is C₅-C₂₀ alkyl, alkenyl or alkynyl, in an amount effective to induce enhanced growth inhibition produced by said chemotherapy agent.

13. The method of claim 12 wherein said cell or tumor is exposed to said potentiating agent prior to exposure of said cell to said chemotherapy agent.