Use of A-Nor-steroids as malignant cells growth inhibitors

A-Nor-5.alpha.-androstane compounds, such as the dipropionate and disuccinate esters of 2.alpha.,17.alpha.-diethynyl-A-Nor-5.alpha.-androstane-2.beta.,17.beta.-di ol and the corresponding 2.alpha.,17.alpha.-diol stereoisomers have an inhibitory effect on malignant cell growth and can be used to treat various carcinomas in mammals.

FIELD OF INVENTION 
This invention relates to the use of certain A-nor-steroids as malignant 
cell growth inhibitors. 
BACKGROUND OF THE INVENTION 
In the early 1960's (Banik, U.K., Pincus, G., and Jacques, J., 1962, 1964), 
first reported the implantation inhibition activities exhibited by certain 
A-nor-steroids as potent progesterone antagonists. In 1965, Pincus and 
Gordon (1965) reported that A-nor-5.alpha.-androstane derivatives, such as 
2.alpha.,17.alpha.-diethyl,2.beta.-17.beta.-diol, 
2.alpha.-ethynyl-2.beta., 17.beta.-diol-17.alpha.-methyl, 
2.alpha.-acetyl-17.alpha.-ethynyl-17.beta.-ol and 
2.alpha.-ethynyl-2.beta.,17.beta.-diol, possess antiestrogenic activity, 
as evidenced by their inhibition of estrogen-induced cell division in 
amitotic cells of cultured hamster's ascites tumor. However, neither 
direct evidence nor implication of anti-cancer activity was reported. 
In the past two decades, A-nor-steroids have been developed exclusively as 
anti-fertility agents. See Li, R.L., 1986; Crabbe, P. et al., 1979; and 
Zhang, Y., 1987. Of the various A-nor-steroids, 
2.alpha.,17.alpha.-diethynyl-A-nor-5.alpha.-androstane-2.beta.,17.beta.-di 
ol dipropionate (Anordrin) possesses significant anti-implantation activity 
in experimental animals (Ku, C.P. et al., 1975), and in clinical trials 
(Hu, C. et al., 1982). In clinical studies, hyperestrogenic side effect 
has been noted (Ku, C.P. et al., 1975). Since estrogen is known to cause 
certain hormonal-dependent cancers, efforts have been made to separate the 
estrogenic activity from its anti-fertility activity by chemical 
modifications based on the structure of A-nor-5.alpha.-androstane. See 
Crabbe, P. et al., 1979, Li, R., 1982, and Li, Y.S., 1983, supra. In spite 
of these extensive activities centered around improving anti-fertility, up 
to now it has not been recognized that A-nor-5.alpha.-androstanes, such as 
2.alpha.,17.alpha.-diethynyl-A-nor-5.alpha.-androstane-2.beta.,17.beta.-di 
ol disuccinate and its analogs inhibit malignant cells growth. 
OBJECTS OF THE INVENTION 
An object of the present invention is to provide A-nor-5.alpha.-androstane 
compositions which are capable of inhibiting malignant cells growth. 
Another object is to provide a method of inhibiting cell growth in vitro 
and in vivo. Another object is to provide compositions and methods for the 
treatment of various cancers. These and other objects of the present 
invention will be apparent to those skilled in the art to which this 
invention pertains. 
SUMMARY OF THE INVENTION 
In a method aspect, this invention relates to a method of inhibiting the 
growth of malignant cells, which comprises exposing the cells to a cell 
growth inhibiting amount of a compound of the formula 
##STR1## 
wherein R and R', which can be alike or different, are hydrogen, succinoyl 
or glutaryl (in free acid or salt form) or propionyl. 
In another method aspect, this invention relates to the use of a compound 
of Formula I for the treatment of carcinomas in mammals. 
In a composition aspect, this invention relates to pharmaceutical 
compositions adapted for the treatment of carcinomas in mammals which 
comprise a malignant cell growth inhibiting amount of a compound of 
Formula I. 
DETAILED DISCLOSURE 
The compounds defined by Formula I are: 
I(a) 
2.alpha.,17.alpha.-diethynyl-A-nor-5.alpha.-androstane-2.beta.,17.beta.-di 
ol; 
I(b) 
2.beta.,17.alpha.-diethynyl-A-nor-5.alpha.-androstane-2.alpha.,17.beta.-di 
ol. 
I(c) 
2.alpha.,17.alpha.-diethynyl-A-nor-5.alpha.-androstane-2.beta.,17.beta.-di 
ol dipropionate (NPI-007, Anordrin, AC-7619); 
I(d) 
2.alpha.,17.alpha.-diethynyl-A-nor-5.alpha.-androstane-2.beta.,17.beta.-di 
ol disuccinate (NPI-008) and salts thereof with a base, e.g., sodium and 
potassium salts; 
I(e) 
2.beta.,17.alpha.-diethynyl-A-nor-5.alpha.-androstane-2.alpha.,17.beta.-di 
ol dipropionate (NPI-009); 
I(f) 
2.beta.,17.alpha.-diethynyl-A-nor-5.alpha.-androstane-2.alpha.,17.beta.-di 
ol disuccinate (NPI-010) and salts thereof with a base, e.g., sodium and 
potassium salts; 
I(g) 
2.alpha.,17.alpha.-diethynyl-A-nor-5.alpha.-androstane-2.beta.,17.beta.-di 
ol diglutarate and salts thereof with a base, e.g., sodium and potassium 
salts; 
I(h) 
2.beta.,17.alpha.-diethynyl-A-nor-5.alpha.-androstane-2.alpha.,17.beta.-di 
ol diglutarate and salts thereof with a base, e.g., sodium and potassium 
salts; and 
I(i) the mono and mixed esters corresponding to each of the above diesters. 
The A-nor-5.alpha.-androstanes of Formula I have the ability to inhibit 
malignant cell growth, both in vitro and in vivo. Compositions based on 
these compounds have potent anti-cancer activity in tumor-bearing mammals, 
e.g., against small cell lung, testicular, esophageal, peptic, colon, 
breast, endometrial, central nervous system, liver, and prostate cancers 
and against systemic cancer, e.g., lymphoma and leukemia. In a preferred 
aspect of this invention, one of these compounds is employed to treat 
lung, ileocecal, breast or endometrial carcinoma, preferably by 
administration systemically to a human being suffering therefrom, e.g., 
orally. 
Considerable experimental and clinical evidence exists which indicate that 
the A-nor-steroids, such as 
2.alpha.,17.alpha.-diethynyl,A-nor-5.alpha.-androstane-2.beta.-17.beta.-di 
ol-dipropionate ("Anordrin") possess significant anti-fertility activity. 
However, no one has reported the anti-cancer activity thereof. This 
invention establishes for the first time that 
2,17.alpha.-diethynyl-A-nor-5.alpha.-androstane-2,17.beta.-diols whose 
hydroxy groups are esterified by succinate groups (NPI-008 and -010) or 
propionate groups (NPI-007 and -009) possess potent malignant cell growth 
inhibitory activity. The compounds employed in the present invention 
differs markedly structurally from existing anti-cancer drugs. They thus 
lack some of the toxic side effects of the currently known anti-cancer 
chemotherapeutic agents. 
One important use for the compounds and compositions employed in the 
present invention lies in their ability to inhibit growth of 
hormone-dependent tumors, such as kidney, breast, endometrial, ovarian, 
and prostate carcinomas, which are characterized by possessing estrogen or 
progesterone receptors and which may, therefore, respond to treatment in 
accordance with the present invention as a consequence of the 
anti-estrogenic or anti-gestagen activity of the compounds of Formula I 
wherein OR is an alpha group. However, the compounds of Formula I wherein 
OR is a beta group lack estrogenic-like activity but nevertheless possess 
significant malignant cell growth inhibiting activity. Therefore, this 
activity apparently cannot be attributed solely to anti-estrogenic 
activity. 
Also included within the scope of the present invention are 
pharmaceutically acceptable salts of salt-forming compounds falling within 
the scope of the above description. Thus, for example, pharmaceutically 
acceptable metal, e.g., sodium and potassium, amine, e.g., 
triethanol-amine and N-methyl-glucamine, and ammonium salts of the 
succinate and glutarate esters can be employed and the pharmaceutically 
acceptable acid addition salts, e.g., hydrochloride, sulfate, phosphate, 
or other inorganic or organic acid, e.g., succinate, glutarate, of the 
amino-amido-succinoyl and -glutaryl esters, can also be employed. 
The present invention is also directed to pro-drug precursors of the active 
compounds disclosed herein. Such compounds are analogs of the present 
invention which have favorable physical properties, such as water 
solubility, for absorption, distribution, or better targeting to the tumor 
cell. These analogous pro-drug compounds can be produced from the active 
compounds based on procedures and factors which are well known to those or 
ordinary skill in the art. Such pro-drug are transformed in vivo to the 
pharmacologically active drug, e.g., the 2,17.beta.-diol free alcohol. 
Specific cancers which may be mentioned as susceptible to treatment by 
administration of compounds in accordance with the present invention 
include endometrial cancer, breast cancer, ovarian cancer, prostate 
cancer, ileocecal cancer, small cell lung cancer, liver cancer, kidney 
cancer, and stomach cancer. 
The compounds of the present invention can be administered by oral, 
parenteral, or intravenous routes, or by absorption through the skin or a 
mucous membrane surface using methods known to those skilled in the art of 
drug delivery. 
For the purpose of therapeutic administration, the active ingredient can be 
incorporated into a solution or suspension. 
Compounds of the present invention can also be administered in combination 
with other therapeutic anti-cancer treatments, such as radiation therapy, 
or in combination with other anti-cancer drugs. It is to be understood 
that dosages may be administered all at once, or may be divided into a 
number of smaller dosages to be administered at varying intervals of time. 
The compounds employed in this invention possess valuable malignant cell 
growth inhibitor activity. Thus, these compounds can be used for the 
palliative treatment of a wide variety of solid and systemic carcinomas. 
They are particularly suited for such use because of the very low toxicity 
compared to the conventional chemotherapeutic agents. The compounds 
employed in this invention are generally administered to mammals, 
including but not limited to humans. 
The pharmacologically active compounds of Formula I can be processed in 
accordance with conventional methods of galenic pharmacy to produce 
medicinal agents for administration to patients, e.g., mammals including 
humans. 
The compounds of this invention can be employed in admixture with 
conventional excipients, i.e., pharmaceutically acceptable organic or 
inorganic carrier substances suitable for parenteral or enteral, e.g., 
oral, application which do not deleteriously react with the active 
compounds. Suitable pharmaceutically acceptable carriers include but are 
not limited to water, salt solutions, alcohols, gum arabic, vegetable 
oils, benzyl alcohols, polyethylene glycols, gelatine, carbohydrates such 
as lactose, amylose or starch, magnesium stearate, talc, silicic acid, 
viscous paraffin, perfume oil, fatty acid monoglycerides and diglycerides, 
pentaerythritol fatty acid esters, hydroxy methylcellulose, polyvinyl 
pyrrolidone, etc. The pharmaceutical preparations can be sterilized and, 
if desired, mixed with auxiliary agents, e.g., lubricants, preservatives, 
stabilizers, wetting agents, emulsifiers, salts for influencing osmotic 
pressure, buffers, coloring, flavoring and/or aromatic substances and the 
like which do not deleteriously react with the active compounds. They can 
also be combined where desired with other active agents. 
For parenteral application, particularly suitable are injectable, sterile 
solutions, preferably oily or aqueous solutions, as well as suspensions, 
emulsions, or implants, including suppositories. Ampoules are convenient 
unit dosages. 
For enteral application, particularly suitable are tablets, dragees, 
liquids, drops, suppositories, or capsules. A syrup, elixir, or the like 
can be used wherein a sweetened vehicle is employed. 
Sustained or directed release compositions can be formulated, e.g., 
liposomes or those wherein the active compound is protected with 
differentially degradable coatings, e.g., by microencapsulation, multiple 
coatings, etc. It is also possible to freeze-dry the new compounds and use 
the lyophilizates obtained, for example, for the preparation of products 
for injection. 
Oral administration is preferred. 
Generally, the compounds employed in this invention are dispensed in unit 
dosage form, e.g., comprising 0.1 mg to 1.0 g thereof in a 
pharmaceutically acceptable carrier per unit dosage. 
The dosage of the compounds according to this invention generally is 0.1 mg 
to 1.0 g, preferably 0.5 to 10 mg/kg/day, when administered to patients, 
e.g., humans, analogous to the known agent tamoxifen or nafoxidine. 
It will be appreciated that the actual preferred amounts of active compound 
in a specific case will vary according to the specific compound being 
utilized, the particular compositions formulated, the mode of application, 
and the particular situs and organism being treated. Dosages for a given 
host can be determined using conventional considerations, e.g., by 
customary comparison of the differential activities of the subject 
compounds and of a known agent, e.g., by means of an appropriate 
conventional pharmacological protocol. 
Contemplated equivalents of the methods of this invention are those 
employing structurally related A-nor-steroids having comparable malignant 
cell growth inhibiting activity, e.g., compounds of one of the Formulae II 
and III: 
##STR2## 
wherein R.sup.1 is --SH, --NH.sub.2, an ester group other than glutaryl, 
propionyl or succinoyl, preferably one which increases lypophylicity, 
e.g., in the case of compounds intended for injection, or hydrophilicity, 
e.g., in the case of compounds intended for oral administration, and/or 
resistance to enzymatic cleavage, e.g., 
##STR3## 
wherein m and n are integers from 1 to 4, preferably m is 2 or 3 and n is 
3, and alkyl is of 1 to 4 carbon atoms, preferably 1, and acid addition 
salts thereof, e.g., HCl, a carbamide group, e.g., --NHCOC.sub.2 H.sub.5 
and --NHYCOCH.sub.2 CH.sub.2 COOH, or an acyl group, e.g., 
##STR4## 
R.sup.2 is --C.tbd.CH, --C.tbd.C--CH.sub.3, or --CH.sub.2 CN; R.sup.3 is 
--H or substituted phenyl, preferably in the p-position, e.g., 
##STR5## 
R.sup.4 is as defined above for R.sup.1 R.sup.5 is --H, --C.tbd.CH, 
--C.tbd.C--CH.sub.3, OR --CH.sub.2 CN; 
R.sup.6 is CH.sub.3 or H; and 
R.sup.7 is CH.sub.3 or C.sub.2 H.sub.5 ; 
and compounds otherwise corresponding to one of Formulae II and III wherein 
R.sup.1 and R.sup.4 are --OH or an ester group as defined above for 
Formula I and R.sup.2 and/or R.sup.5 is other than --C.tbd.CH or R.sup.3 
and/or R.sup.6 is other than H, or R.sup.7 is --C.sub.2 H.sub.5, including 
(a) those wherein R.sup.1 and R.sup.4 are ester groups, e.g., succinyloxy, 
.beta.-carboalkoxypropionyloxy and propionyloxy, 
(b) those wherein R.sup.4 is OH or an acyl group, e.g., 
##STR6## 
(c) those of Formula II wherein 
##STR7## 
wherein m is 2 or 3, or 
##STR8## 
R.sup.2 .dbd.R.sup.5 .dbd.--C.tbd.CH or --C.tbd.C--CH.sub.3 and R.sup.3 is 
H, 
(d) those of Formula III wherein 
##STR9## 
R.sup.2 .dbd.R.sup.5 .dbd.--C.tbd.CH or --C.tbd.C--CH.sub.3 and R.sup.3 is 
H, 
(e) those wherein R.sup.2 .dbd.R.sup.5 .dbd. --C.tbd.CH or 
--C.tbd.C--CH.sub.3, R.sup.1 .dbd.R.sup.4 .dbd. OH and R.sup.3 is H, 
especially those of Formula II, 
(f) those wherein R.sup.6 is H, and 
(g) those wherein R.sup.3 is 
##STR10## 
Standard procedures, such as esterification, hydrolysis, amidation of 
carboxylic acids or esters, lead to the substituents R.sup.1, R.sup.2, 
R.sup.4, and R.sup.5. 
Without further elaboration, it is believed that one skilled in the art 
can, using the preceding description, utilize the present invention to its 
fullest extent. The following preferred specific embodiments are, 
therefore, to be construed as merely illustrative, and not limitative of 
the remainder of the disclosure in any way whatsoever.