WO2019166430A1

WO2019166430A1 - Estriol component for use in the treatment of er-positive cancers

Info

Publication number: WO2019166430A1
Application number: PCT/EP2019/054726
Authority: WO
Inventors: Herman Jan Tijmen Coelingh Bennink
Original assignee: Pantarhei Oncology B.V.
Priority date: 2018-02-28
Filing date: 2019-02-26
Publication date: 2019-09-06

Abstract

The present invention relates to the use of an estriol component in the treatment of estrogen receptor positive (ER-positive) cancer in a non-pregnant female human patient, said estriol component being selected from estriol, prodrugs of estriol and combinations thereof, and the treatment comprising uninterrupted, at least once dailyoral administration of doses of the estriol component during a period of at least 4 weeks, wherein the doses are orally administered in dosages equivalent to a daily oral dosage of 0.01 to 2 mg estriol. It was surprisingly found that oral administration of estriol at low dosages can significantly reduce growth of estrogen receptor positive (ER-positive) cancer cells by inducing apoptosis.

Description

ESTRIOL COMPONENT FOR USE IN THE TREATMENT OF ER-POSITIVE CANCERS

Field of the invention

The present invention relates to the field of cancer treatment and , in particular, to the treatment of estrogen- receptors positive (ER-positive) cancers in human females. The treatment according to the invention involves the treatment of ER-positive cancers by oral administration of an estriol component.

Background of the invention

It is well-established that growth of ER-positive cancerous cells is stimulated by estrogens. A common therapeutic approach used in first line treatment of patients diagnosed with ER-positive cancer comprises administering estrogen receptor antagonists, selective estrogen-receptor receptor modulators (SERMs), aromatase inhibitors, etc. Typical drawbacks of the use of the currently available therapeutic agents such as SERMs include a variety of bothersome side effects such as arthralgia and hot flushes, negatively influencing daily functioning.

Estriol (E3) is an estrogen hormone abundantly present in the plasma of pregnant women.

Lemon H .M. has reported that estriol provides a protective effect against the development of breast cancer (Estriol and prevention of breast cancer, The Lancet (1973), 10:546-47). Estriol was found to be the most active protective estrogen yet tested against neoplasms induced by 20 mg oral 7,12-dimethyl- benzanthracene (DMBA) or by 50 mg procarbazine (PC) in Sprague-Dawley female rats. The author expressed the hope that these observations will provide a basis for extended clinical trials of estriol in premenopausal Caucasian women. Candidates would include those with a familial history of breast cancer, those with genetically impaired estrogen hydroxylation, those with precancerous breast changes, or those who chose to avoid pregnancy. Reference is made to an ongoing clinical trial in breast cancer, in which 5.0 mg estriol per day is well tolerated for as long as eleven months.

A prophylactic effect was also observed by Lemon in another study conducted when administering estriol in rats before chemically inducing mammary carcinomas with DMBA, therefore suggesting that administration of estriol, especially to young nulliparous women could offer a method for prevention of breast cancer ( Estriol prevention of mammary carcinoma induced by 7, 12 dimethylbenzanthracene, Cancer Research (1975) 35:1341 -1353). Further research by Lemon et al . ( Inhibition of radiogenic mammary carcinoma in rats by estriol or tamoxifen, Cancer (1989), 63:1685-1692) has shown that estriol reduced the incidence of radiogenic mammary carcinoma in rats.

Lippman et al. ( Effects of Estrone, Estradiol, and Estriol on Hormone responsive Human Breast Cancer in Long-Term Tissue, Cancer Research (1977), 37, 1901 -1907) compared the effects of estrone, estradiol, and estriol on MCF-7 human breast cancer. In this estrogen-responsive cell line, all three estrogens were capable of inducing equivalent stimulation of amino acid and nucleoside incorporation. Estriol was capable of partially overcoming anti-estrogen inhibition with Tamoxifen (ICI 46474), even when anti-estrogen is present in 1000-fold excess. Anti-estrogen effects were completely overcome by 100-fold less estriol. All three steroids were found to bind to a high-affinity estrogen receptor found in these cells. The apparent dissociation constant was lower for estradiol than for estrone and estriol, but all three bind to an equal number of sites when saturating concentrations are used. The authors conclude that estriol can bind to estrogen receptor and stimulate human breast cancer in tissue culture and that their data do not support an anti-estrogenic role for estriol in human breast cancer.

The effect of estriol on growth of MCF-7 human breast cancer cell lines has also been investigated by Diller et al. ( Effects of estriol on growth, gene expression and ERE activation in human breast cancer cell lines. Maturitas (2014) 77, 336-343). It was found that estriol acted as a potent estrogen and exerted a mitogenic effect on T-47D and MCF-7 cells at concentrations of 10 ⁹ M (288 pg/ml) and higher. With regard to activation of an estrogen response element (ERE) in breast cancer cells, effects of E3 were visible at 10 ¹° M. The same concentrations of E3 activated expression of the estrogen-responsive gene PR and of the proliferation genes cyclin A2, cyclin B1 , Ki-67, c-myc and b-myb, providing molecular mechanisms underlying the observed growth increase. The authors conclude: Like E2 (estradiol), low levels of E3 were able to trigger a robust estrogenic response in breast cancer cells. Thus, our data suggest caution regarding use of E3 by breast cancer survivors.

The use of estriol as a potential agent in the treatment of cancer has been investigated by Girgert et al. (Inhibition of GPR30 by estriol prevents growth stimulation of triple-negative breast cancer cells by 17b- estradiol, BMC Cancer (2014) 14:935) showed that GPR30 is involved in growth stimulation of triplenegative breast cancer by 17b-b5ΐ^ίoI. Estriol effectively inhibited signal transduction of GPR30 and successfully prevented growth promotion by 17b-b5ΐ^ίoI. These results clearly show that a pharmacological inhibition of GPR30 is a promising targeted treatment option for triple-negative breast cancer. However, the authors conclude that the concentrations of estriol needed for sufficient growth inhibition are unfortunately unphysiologically high and that consequently there is a need for developing more effective inhibitors for GPR30.

Currently, the therapeutic indications of estriol are restricted to hormone replacement therapy (HRT). Commercially available are 1 mg or 2 mg estriol tablets for oral administration (Ovestin^®) and creams/ovules for intra-vaginal administration (Synapause-E^®). Patients that have or have had ER-positive cancer are explicitly warned not to use these products.

Moegele et al. ( Vaginal Estrogen Therapy for Patients with Breast Cancer, Geburtshilfe Frauenheilkd. (2013) Oct; 73(10), 1017-1022) recommend that the use of topical hormone therapy, after the diagnosis of breast cancer has been made, should only be initiated in cases where the patient experiences a high degree of distress with corresponding impairments in quality of life and after comprehensive consultations with the patient about the current state of knowledge and the fact that the possibility of an increased risk of recurrence cannot be excluded. When a topical hormone-containing therapy is used, an ultralow dosed formulation (e.g., estriol 0.03 mg) should be used whenever possible in the first few weeks. According to the authors further prospective randomised trials are needed to assess the safety of topical hormonal therapy for breast cancer patients, especially in the light of the degree of distress and impairments in quality of life experienced by these patients.

Kuhl ( Pharmacology of estrogens and progestogens: influence of different routes of administration, CLIMACTERIC (2005); 8(Suppl 1 ):3-63) provides a review comprising the pharmacokinetics and pharmacodynamics of natural and synthetic estrogens and progestogens used in contraception and therapy. It is reported that the standard dose of orally administered estriol is 1 -2 mg, preferably taken as a single dose in the evening. Oral treatment with estriol may improve climacteric symptoms dose- and time- dependently. Estriol also improved effectively atrophic symptoms in the urogenital tract, but had no significant effect on urinary incontinence. Oral treatment with 2 mg estriol reversed the postmenopausal decline in skin thickness and collagen content, but had no significant effect on bone resorption and fracture risk. Estriol has a proliferative effect on breast epithelium, but does not increase mammographic density.

Summary of the invention

The present inventors have surprisingly found that oral administration of estriol at low dosages can significantly reduce growth of estrogen receptor positive (ER-positive) cancer cells by inducing apoptosis.

Accordingly, the present invention relates to the use of an estriol component in the treatment of ER-positive cancer in a non-pregnant female human patient, said treatment comprising uninterrupted, at least once daily oral administration of low doses of the estriol component during a period of at least 4 weeks, said estriol component being selected from estriol, prodrugs of estriol and combinations thereof. More particularly, the present treatment of ER-positive cancer comprises uninterrupted oral administration of doses of the estriol component during a period of at least 4 weeks, wherein the doses are orally administered in dosages equivalent to a daily oral dosage of 0.01 to 2 mg estriol.

Examples of ER-positive cancers that can be treated by the present method include ER-positive breast cancer, ER-positive ovarian cancer, ER-positive uterine cancer (including ER-positive endometrium cancer and ER-positive cervical cancer), ER-positive fallopian tube cancer and ER-positive peritoneal cancer.

In comparison to other estrogens, estriol presents a lower risk of causing cardiovascular events (Toy et al.: The effects of long-term therapy with oestriol succinate on the haemostatic mechanism in postmenopausal women, Br J Obstet Gynaecol (1978) 85:363-366.). Furthermore, unlike anti-estrogens and SERMs, estriol does not give rise to complaints caused by estrogen deficiency (e.g. arthralgia and/or hot flushes).

Detailed description of the invention

The present invention relates to an estriol component for use in the treatment of estrogen receptor positive (ER-positive) cancer in a non-pregnant female human patient, said estriol component being selected from estriol, prodrugs of estriol and combinations thereof, and the treatment comprising uninterrupted, at least once daily oral administration of doses of the estriol component during a period of at least 4 weeks, wherein the doses are orally administered in dosages equivalent to a daily oral dosage of 0.01 to 2 mg estriol.

The term“estriol component”, as used herein, encompasses estriol as well as prodrugs of estriol. Estriol esters are examples of estriol prodrugs that can be used in accordance with the present invention. Preferably, these estriol esters are estriol derivatives wherein the hydrogen atom of at least one of the hydroxyl groups has been substituted by an acyl radical of a hydrocarbon carboxylic, sulfuric acid, sulfonic acid or sulfamic acid of 1 -25 carbon atoms; or combinations thereof. Examples of estriol esters that can be employed as estriol component in the present treatment include: estriol succinate, estriol sulfamate, estriol diacetate benzoate, estriol tripropionate and estriol sulfate.

The term “estriol” refers to estra-1 ,3,5(10)-triene-3, 16a, 17p-triol. The term estriol also encompasses hydrates of this estrogen.

The term“estrogen receptor positive cancer” as used herein refers to cancer cells that have a receptor protein that binds the hormone estrogen. Cancer cells that are estrogen receptor positive may need estrogen to grow, and may stop growing or die when treated with substances that block the binding and actions of estrogen. A cancer is progesterone-receptor-positive if it has progesterone receptors. Again, this means that the cancer cells may receive signals from progesterone that could promote their growth. Roughly two out of every three breast cancers test positive for hormone receptors. Testing for hormone receptors is used to predict whether the cancer is likely to respond to hormonal therapy or other treatments. Hormonal therapy includes medications that either lower the amount of estrogen in the body or block estrogen from supporting the growth and function of breast cells. If the cancer is hormone-receptor-negative (no receptors are present), then hormonal therapy is unlikely to work.

The estriol component is typically administered in the present treatment in an amount effective to reduce growth of ER-positive cancer cells.

In accordance with a preferred embodiment, the present treatment comprises uninterrupted oral administration of doses of the estriol component during a period of at least 4 weeks in dosages equivalent to a daily oral dosage of not more than 1 .5 mg estriol, more preferably of not more than 1 mg estriol, even more preferably of not more than 0.8 mg estriol and yet more preferably of not more than 0.6 mg estriol.

The treatment typically comprises uninterrupted oral administration of doses of the estriol component during a period of at least 4 weeks in dosages equivalent to a daily oral dosage of at least 0.03 mg estriol, more preferably of at least 0.1 mg estriol, even more preferably of at least 0.2 mg estriol and yet more preferably of at least 0.3 mg estriol.

According to a particularly preferred embodiment, the estriol component that is administered to the female human patient is estriol.

According to a particularly preferred embodiment, the present treatment comprises uninterrupted oral administration of estriol for at least 4 weeks in a daily dosage of not more than 2 mg, more preferably of not more than 1 .5 mg, even more preferably of not more than 1 mg, yet more preferably of not more than 0.8 mg and most preferably of not more than 0.6 mg.

The present treatment preferably comprises uninterrupted oral administration of estriol for at least 4 weeks in a daily dosage of not more than 50 pg per kg bodyweight, more preferably of not more than 35 pg per kg bodyweight, even more preferably of not more than 25 pg per kg bodyweight, yet more preferably of not more than 20 pg per kg bodyweight and most preferably of not more than 15 pg per kg bodyweight.

In a further preferred embodiment, the treatment comprises uninterrupted oral administration of estriol during a period of at least 4 weeks in a daily dose of at least 0.01 mg, more preferably of at least 0.03 mg, even more preferably of at least 0.1 mg, yet more preferably of at least 0.2 mg and most preferably of at least 0.3 mg.

The treatment according to the present invention typically comprises uninterrupted oral administration of estriol for at least 4 weeks in a daily dosage of at least 0.2 pg per kg bodyweight, more preferably of at least 0.6 pg per kg bodyweight, even more preferably of at least 2 pg per kg bodyweight, yet more preferably of at least 4 pg per kg bodyweight and most preferably of at least 6 pg per kg bodyweight

The present treatment preferably comprises uninterrupted administration of the estriol component during a period of at least 4 weeks to achieve an average serum estriol concentration in the human patient after 4 weeks of uninterrupted administration that does not exceed 50 pg/mL, more preferably does not exceed 40 pg/mL, even more preferably does not exceed 30 pg/mL, yet more preferably does not exceed 25 pg/mL and most preferably does not exceed 20 pg/mL. Typically, the present treatment achieves an average serum estriol concentration in the human patient after 4 weeks of uninterrupted administration of at least 12 pg/mL, more preferably of at least 15 pg/mL, even more preferably of at least 18 pg/mL and most preferably of at least 20 pg/mL. The terminology“average serum estriol concentration after 4 weeks of uninterrupted administration” as used herein refers to the time averaged concentration of estriol (free and bound) in the serum of the female human patient during the 24 hours following the last administration event of 4 weeks of uninterrupted administration of estriol.

Suitable oral dosage forms that may be used to administer the estriol component to the female human patient include tablets, pills and capsules.

In the present treatment, the estriol component is administered at least once daily during the period of uninterrupted oral administration. Preferably, the estriol component is administered once daily.

Typically, the present treatment comprises uninterrupted administration of the estriol component for at least 8 weeks, more preferably for at least 16 weeks, even more preferably for at least 30 weeks.

A particularly preferred embodiment of the invention comprises the treatment of pre- or post-menopausal women having low plasma levels of estradiol (E2). Accordingly, in a preferred embodiment, the female patient is post-menopausal and/or had undergone oophorectomy.

The present treatment preferably comprises administration of the estriol component to a female human patient suffering from ER-positive breast cancer, ER-positive ovarian cancer, ER-positive uterine cancer (including ER-positive endometrium cancer and ER-positive cervical cancer), ER-positive fallopian tube cancer and ER-positive peritoneal cancer. The present treatment is deemed to be particularly effective in the treatment of ER-positive breast cancer.

According to a further preferred embodiment of the invention, the treatment with estriol component is a first line treatment, i.e. the ER-positive cancer has not been treated previously. In another preferred embodiment of the present treatment, said treatment does not comprise coadministration of an anti-estrogen, an aromatase inhibitor or a SERM.

The invention is further illustrated by the following non-limiting examples.

Examples

Example 1

In vitro studies were conducted to assess the potential of estriol to induce apoptosis in MCF-7 cells (a breast cancer cell line).

MCF-7 cells were plated in 12-well plates at a density of 30,000 cells per well. The cells were maintained in IMEM with 5% charcoal stripped FBS (DCC-FBS). On Day 3, the medium was replaced with phenol red free IMEM with 5% DCC-FBS. Cells were washed with PBS once before treatment with estriol.

Different concentrations of estriol were tested, ranging from 10 M to 10 M. The tests were carried out in duplicate.

On Day 5 , the plates were analysed by means of the apoptosis ELISA assay (Roche Cell Death Detection ELISA kit) according to the protocol of the manufacturer. Apoptosis was expressed as OD_405nm per 10000 cells.

The results are shown in Table 1 .

Table 1

These results show that estriol was able to induce apoptosis at very low concentrations of 10 M and

-12

10 M and inhibited apoptosis at concentrations of 10^_1°, 10^-8 and 10^-6 M . Example 2

In vitro studies were conducted to assess the potential of estriol to induce growth in MCF-7 cells.

MCF-7 cells were plated in 6-well plates at a density of 30,000 cells per well. The cells were maintained in IMEM with 5% charcoal stripped FBS (DCC-FBS). On Day 3, the medium was replaced with phenol red free IMEM with 5% DCC-FBS. Cells were washed with PBS once before treatment with estriol.

-14 -4

On Day 5, the medium was changed and on Day 7 plates were subjected to a cell count analysis.

The results are shown in Table 2.

Table 2

These results show that at concentrations of 10^_1° M to 10^-5 M, estriol stimulates growth of MCF-7 cells. The reduction in growth at an estriol concentration of 10^-4 M is believed to be caused by cytotoxicity.

Example 3

-12 -5

Different concentrations of estriol were tested, ranging from 10 M to 10 M. The tests were carried out in duplicate. On Day 5, the medium was changed and on Day 7 plates were subjected to a cell count analysis.

The results are shown in Table 3.

Table 3

These results show that at concentrations of 10 ¹⁰ M to 10 ⁵ M, estriol stimulates growth of MCF-7 cells.

Claims

1 . Estriol component for use in the treatment of estrogen receptor positive (ER-positive) cancer in a non-pregnant female human patient, said estriol component being selected from estriol, prodrugs of estriol and combinations thereof, and the treatment comprising uninterrupted, at least once daily oral administration of doses of the estriol component during a period of at least 4 weeks, wherein the doses are orally administered in dosages equivalent to a daily oral dosage of 0.01 to 2 mg estriol.

2. Estriol component for use according to claim 1 , wherein the treatment comprises uninterrupted oral administration of doses of the estriol component during a period of at least 4 weeks in dosages equivalent to a daily oral dosage of not more than 1.5 mg estriol, preferably of not more than 1 mg estriol, more preferably of not more than 0.8 mg estriol and even more preferably of not more than 0.6 mg estriol.

3. Estriol component for use according to claim 1 or 2, wherein the treatment comprises uninterrupted oral administration of doses of the estriol component during a period of at least 4 weeks in dosages equivalent to a daily oral dosage of at least 0.03 mg estriol, preferably of at least 0.1 mg estriol, more preferably of at least 0.2 mg estriol and even more preferably of at least 0.3 mg estriol.

4. Estriol component for use according to any one of the preceding claims, wherein the treatment comprises uninterrupted oral administration of estriol for at least 4 weeks in a daily dosage of not more than 2 mg, preferably of not more than 1 .5 mg, more preferably of not more than 1 mg, even more preferably of not more than 0.8 mg and yet more preferably of not more than 0.6 mg.

5. Estriol component for use according to any one of the preceding claims, wherein the treatment comprises uninterrupted oral administration of estriol during a period of at least 4 weeks in a daily dose of at least 0.01 mg, preferably of at least 0.03 mg, more preferably of at least 0.1 mg, even more preferably of at least 0.2 mg and yet more preferably at least 0.3 mg.

6. Estriol component for use according to any one of the preceding claims, wherein the estriol

component is administered once daily.

7. Estriol component for use according to any of the preceding claims, wherein the treatment comprises uninterrupted administration of the estriol component for at least 8 weeks, preferably at least 16 weeks.

8. Estriol component for use according to any of the preceding claims, wherein the prodrug of estriol component is selected from estriol succinate, estriol sulfamate, estriol diacetate benzoate, estriol tripropionate, estriol sulfate and combinations thereof.

9. Estriol component for use according any one of the preceding claims, wherein the estriol component is estriol.

10. Estriol component for use according to any one of the preceding claims, wherein the female patient is post-menopausal and/or has undergone oophorectomy.

1 1 . Estriol component for use according to any one of the preceding claims, wherein the ER-positive cancer is selected from ER-positive breast cancer, ER-positive ovarian cancer, ER-positive uterine cancer, ER-positive fallopian tube cancer and ER-positive peritoneal cancer.

12. Estriol component for use according to claim 1 1 , wherein the ER-positive cancer is breast cancer.

13. Estriol component for use according to any of the preceding claims, wherein the treatment is a first line treatment.

14. Estriol component for use according to any one of the preceding claims, wherein the treatment does not comprise co-administration of an anti-estrogen, an aromatase inhibitor or a SERM