Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Cyclopentanohydrophenanthrene ring system doai
Reexamination Certificate
2000-05-17
2003-12-30
Badio, Barbara P. (Department: 1616)
Drug, bio-affecting and body treating compositions
Designated organic active ingredient containing
Cyclopentanohydrophenanthrene ring system doai
C552S519000
Reexamination Certificate
active
06670353
ABSTRACT:
The present invention relates to a compound.
In particular the present invention relates to a compound and to a pharmaceutical composition comprising the compound. The present invention also relates to the use of that compound in the field of medicine.
Evidence suggests that oestrogens are the major mitogens involved in promoting the growth of tumours in endocrine-dependent tissues, such as the breast and endometrium. Although plasma oestrogen concentrations are similar in women with or without breast cancer, breast tumour oestrone and oestradiol levels are significantly higher than in normal breast tissue or blood. In situ synthesis of oestrogen is thought to make an important contribution to the high levels of oestrogens in tumours and therefore specific inhibitors of oestrogen biosynthesis are of potential value for the treatment of endocrine-dependent tumours.
Over the past two decades, there has been considerable interest in the development of inhibitors of the aromatase pathway which converts the androgen precursor androstenedione to oestrone. However, there is now evidence that the oestrone sulphatase (E1-STS) pathway, i.e. the hydrolysis of oestrone sulphate to oestrone (E1S to E1), as opposed to the aromatase pathway, is the major source of oestrogen in breast tumours. This theory is supported by a modest reduction of plasma oestrogen concentration in postmenopausal women with breast cancer treated by aromatase inhibitors, such as aminoglutethimide and 4-hydroxyandrostenedione and also by the fact that plasma E1S concentration in these aromatase inhibitor-treated patients remains relatively high. The long half-life of E1S in blood (10-12 h) compared with the unconjugated oestrogens (20 min) and high levels of steroid sulphatase activity in liver and, normal and malignant breast tissues, also lend support to this theory.
PCT/GB92/01587 teaches novel steroid sulphatase inhibitors and pharmaceutical compositions containing them for use in the treatment of oestrone dependent tumours, especially breast cancer. These steroid sulphatase inhibitors are sulphamate esters. Examples of such inhibitors are sulphamate ester derivatives of steroids.
As is well known in the art, steroids have the general formula of:
In the above formula, the ring components have been labelled in the conventional manner.
A preferred compound of PCT/GB92/101587 is oestrone-3-sulphamate (otherwise known as “EMATE”), which has the following structure:
It is known that EMATE is a potent E1-STS inhibitor as it displays more than 99% inhibition of E1-STS activity in intact MCF-7 cells at 0.1 &mgr;M. EMATE also inhibits the E1-STS enzyme in a time- and concentration-dependent manner, indicating that it acts as an active site-directed inactivator.
Although EMATE was originally designed for the inhibition of E1-STS, it also inhibits dehydroepiandrosterone sulphatase (DHA-STS), which is an enzyme that is believed to have a pivotal role in regulating the biosynthesis of the oestrogenic steroid androstenediol.
Also, there is now evidence to suggest that androstenediol may be of even greater importance as a promoter of breast tumour growth. EMATE is also active in vivo as almost complete inhibition of rat liver E1-STS (99%) and DHA-STS (99%) activities resulted when it is administered either orally or subcutaneously. In addition, EMATE has been shown to have a memory enhancing effect in rats. Studies in mice have suggested an association between DHA-STS activity and the regulation of part of the immune response. It is thought that this may also occur in humans. The bridging O-atom of the sulphamate moiety in EMATE is important for inhibitory activity. Thus, when the 3-O-atom is replaced by other heteroatoms—as in oestrone-3-N-sulphamate and oestrone-3-S-sulphamate—these analogues are weaker non-time-dependent inactivators.
Although optimal potency for inhibition of E1-STS may have been attained in EMATE, it is possible that oestrone may be released during sulphatase inhibition, and that EMATE and its oestradiol congener may possess oestrogenic activity.
The present invention seeks to provide novel compounds suitable for the inhibition of E1-STS but preferably wherein those compounds also have an oestrogenic effect.
Certain aspects of the present invention are presented in the accompanying claims.
A key advantage of the present invention is that the sulphamate compounds of the present invention can act as E1-STS inhibitors.
Another advantage of the compounds of the present invention is that they may be potent in vivo.
In addition, the compounds of the present invention can be used as oestrogenic compounds. Preferably some of the compounds are potent oestrogenic compounds. More preferably some of the compounds are highly oestrogenic compounds.
In a preferred embodiment therefore, the present invention therefore provides sulphamate compounds which are both steroid sulphatase inhibitors and oestrogenic.
The compounds of the present invention are also advantageous in that they may be orally active.
The sulphamate compounds of the present invention are believed to be useful for the treatment of breast cancer, or endocrine-dependent cancers, or endocrine- or oestrogen-dependent conditions and/or illnesses and/or cancers; see also documents cited herein (compounds therein also so useful).
In addition, the sulphamate compounds of the present invention are useful for the treatment of non-malignant conditions, such as the prevention of auto-immune diseases, particularly when pharmaceuticals may need to be administered from an early age.
The sulphamate compounds of the present invention are also believed to have therapeutic uses other than for the treatment of endocrine-dependent cancers, such as the treatment of autoimmune diseases and hormone replacement therapy.
The sulphamate compounds of the present invention are also believed to be useful for birth control etc.
These and further aspects of the present invention are now described.
Some or all of the ring components may be fused together or joined via one or more suitable spacer groups. The present invention also encompasses combinations thereof.
The term “sulphamate” as used herein includes an ester of sulphamic acid, or an ester of an N-substituted derivative of sulphamic acid, or a salt thereof.
Preferably, the sulphamate group has the formula:
wherein each of R
1
and R
2
is independently selected from H or a hydrocarbyl group.
The term “hydrocarbyl group” as used herein means a group comprising at least C and H and may optionally comprise one or more other suitable substituents. Examples of such substituents may include halo-, alkoxy-, nitro-, an alkyl group, a cyclic group etc. In addition to the possibility of the substituents being a cyclic group, a combination of substituents may form a cyclic group. If the hydrocarbyl group comprises more than one C then those carbons need not necessarily be linked to each other. For example, at least two of the carbons may be linked via a suitable element or group. Thus, the hydrocarbyl group may contain hetero atoms. Suitable hetero atoms will be apparent to those skilled in the art and include, for instance, sulphur, nitrogen and oxygen. A non-limiting example of a hydrocarbyl group is an acyl group.
In one preferred embodiment of the present invention, the hydrocarbyl group is a hydrocarbon group.
Here the term “hydrocarbon” means any one of an alkyl group, an alkenyl group, an alkynyl group, which groups may be linear, branched or cyclic, or an aryl group. The term hydrocarbon also includes those groups but wherein they have been optionally substituted. If the hydrocarbon is a branched structure having substituent(s) thereon, then the substitution may be on either the hydrocarbon backbone or on the branch; alternatively the substitutions may be on the hydrocarbon backbone and on the branch.
Preferably, R
1
and R
2
are independently selected from H or alkyl, cycloalkyl, alkenyl and aryl, or together represent alkylene, wherein the or each alkyl or cycloalkyl or alkenyl or optionally contain one or more hetero atoms o
Lloyd Potter Barry Victor
Reed Michael John
Badio Barbara P.
Frommer Lawrence & Haug
Kowalski Thomas J.
Sterix Limited
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