Endocrine responses to long-term administration of the antiprogesterone RU486 in patients with pelvic endometriosis

Progesterone resistance in endometriosis: A pathophysiological perspective and potential treatment alternatives

Background

Endometriosis is a common gynecological disease affecting women of reproductive age. Patients with endometriosis frequently experience severe chronic pain and have higher chances to experience infertility. Progesterone resistance is a major problem that develops during the medical treatment of endometriosis, which often leads to treatment failure of hormonal therapies. Previous studies indicated that the dysregulation of progesterone receptors (PR) is the primary factor leading to progesterone resistance in endometriosis.

Methods

This review article systematically reviewed and summarized findings extracted from previously published papers available on PubMed, encompassing both experimental studies and clinical trials.

Main findings

Various determinants influencing PR expression in endometriosis have been identified, including the environmental toxins, microRNAs, cell signaling pathways, genetic mutations, and the pro-inflammatory cytokines. The selective estrogen/progesterone receptor modulators have emerged as novel therapeutic approaches for treating endometriosis, offering potential improvements in overcoming progesterone resistance.

Conclusion

Concerns and limitations persist despite the newly developed drugs. Therefore, studies on unraveling new therapeutic targets based on the molecular mechanisms of progesterone resistance is warranted for the development potential alternatives to overcome hormonal treatment failure in endometriosis.

Hormonal treatments for endometriosis: The endocrine background

Endometriosis is a benign uterine disorder characterized by menstrual pain and infertility, deeply affecting women's health. It is a chronic disease and requires a long term management. Hormonal drugs are currently the most used for the medical treatment and are based on the endocrine pathogenetic aspects. Estrogen-dependency and progesterone-resistance are the key events which cause the ectopic implantation of endometrial cells, decreasing apoptosis and increasing oxidative stress, inflammation and neuroangiogenesis. Endometriotic cells express AMH, TGF-related growth factors (inhibin, activin, follistatin) CRH and stress related peptides. Endocrine and inflammatory changes explain pain and infertility, and the systemic comorbidities described in these patients, such as autoimmune (thyroiditis, arthritis, allergies), inflammatory (gastrointestinal/urinary diseases) and mental health disorders.The hormonal treatment of endometriosis aims to block of menstruation through an inhibition of hypothalamus-pituitary-ovary axis or by causing a pseudodecidualization with consequent amenorrhea, impairing the progression of endometriotic implants. GnRH agonists and antagonists are effective on endometriosis by acting on pituitary-ovarian function. Progestins are mostly used for long term treatments (dienogest, NETA, MPA) and act on multiple sites of action. Combined oral contraceptives are also used for reducing endometriosis symptoms by inhibiting ovarian function. Clinical trials are currently going on selective progesterone receptor modulators, selective estrogen receptor modulators and aromatase inhibitors. Nowadays, all these hormonal drugs are considered the first-line treatment for women with endometriosis to improve their symptoms, to postpone surgery or to prevent post-surgical disease recurrence. This review aims to provide a comprehensive state-of-the-art on the current and future hormonal treatments for endometriosis, exploring the endocrine background of the disease.

Selective Progesterone Receptor Modulators (SPRMs) and Androgen Receptor Modulators (SARMs) as Treatment for Benign Gynecologic Diseases

Common benign gynecologic conditions such as uterine fibroids and endometriosis are linked to chronic pelvic pain, abnormal and heavy uterine bleeding, and infertility. Effective medical management of these diseases is an unmet need. The steroid hormones progesterone (P4), estrogen (E2), and testosterone play a major role in reproductive physiology and uterine pathologies. Notably, selective progesterone receptor modulators have shown considerable promise as treatment options for some hormone-dependent conditions. More limited data are available regarding the safety and efficacy of selective androgen receptor modulators. In this report we review current evidence for selective progesterone receptor modulators and selective androgen receptor modulators as treatment options for benign gynecologic conditions.

Role of medical treatment of endometriosis

Endometriosis is a chronic benign disease that affects women of reproductive age. Medical therapy is often the first line of management for women with endometriosis in order to ameliorate symptoms or to prevent post-surgical disease recurrence. Currently, there are several medical options for the management of patients with endometriosis and long-term treatments should balance clinical efficacy (controlling pain symptoms and preventing recurrence of disease after surgery) with an acceptable safety-profile. Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used in the treatment of chronic inflammatory conditions, being efficacious in relieving primary dysmenorrhea. Combined oral contraceptives and progestins, available for multiple routes of administration, are commonly administered as first-line hormonal therapies. Several studies demonstrated that they succeed in improving pain symptoms in the majority of patients; moreover, they are well tolerated and not expensive. Gonadotropin-releasing hormone-agonists are prescribed when first line therapies are ineffective, not tolerated or contraindicated. Even if these drugs are efficacious in treating women not responding to COCs or progestins, they are not orally available and have a less favorable tolerability profile (needing an appropriate add-back therapy). Because few data are available on long-term efficacy and safety of aromatase inhibitors they should be reserved only for women with symptoms who are refractory to other treatments only in a research environment. Almost all of the currently available treatment options for endometriosis suppress ovarian function and are not curative. For this reason, research into new drugs is unsurprisingly demanding. Amongst the drugs currently under investigation, gonadotropin-releasing hormone antagonists have shown most promise, currently in late-stage clinical development. There is a number of potential future therapies currently tested only in vitro, in animal models of endometriosis or in early clinical studies with a small sample size. Further studies are necessary to conclude whether these treatments would be of value for the treatment of endometriosis.

Selective Progesterone Receptor Modulators-Mechanisms and Therapeutic Utility

Selective progesterone receptor modulators (SPRMs) are a new class of compounds developed to target the progesterone receptor (PR) with a mix of agonist and antagonist properties. These compounds have been introduced for the treatment of several gynecological conditions based on the critical role of progesterone in reproduction and reproductive tissues. In patients with uterine fibroids, mifepristone and ulipristal acetate have consistently demonstrated efficacy, and vilaprisan is currently under investigation, while studies of asoprisnil and telapristone were halted for safety concerns. Mifepristone demonstrated utility for the management of endometriosis, while data are limited regarding the efficacy of asoprisnil, ulipristal acetate, telapristone, and vilaprisan for this condition. Currently, none of the SPRMs have shown therapeutic success in treating endometrial cancer. Multiple SPRMs have been assessed for efficacy in treating PR-positive recurrent breast cancer, with in vivo studies suggesting a benefit of mifepristone, and multiple in vitro models suggesting the efficacy of ulipristal acetate and telapristone. Mifepristone, ulipristal acetate, vilaprisan, and asoprisnil effectively treated heavy menstrual bleeding (HBM) in patients with uterine fibroids, but limited data exist regarding the efficacy of SPRMs for HMB outside this context. A notable class effect of SPRMs are benign, PR modulator-associated endometrial changes (PAECs) due to the actions of the compounds on the endometrium. Both mifepristone and ulipristal acetate are effective for emergency contraception, and mifepristone was approved by the US Food and Drug Administration (FDA) in 2012 for the treatment of Cushing's syndrome due to its additional antiglucocorticoid effect. Based on current evidence, SPRMs show considerable promise for treatment of several gynecologic conditions.

90 YEARS OF PROGESTERONE: Selective progesterone receptor modulators in gynaecological therapies

Abnormal uterine bleeding (AUB) is a chronic, debilitating and common condition affecting one in four women of reproductive age. Current treatments (conservative, medical and surgical) may be unsuitable, poorly tolerated or may result in loss of fertility. Selective progesterone receptor modulators (SPRMs) influence progesterone-regulated pathways, a hormone critical to female reproductive health and disease; therefore, SPRMs hold great potential in fulfilling an unmet need in managing gynaecological disorders. SPRMs in current clinical use include RU486 (mifepristone), which is licensed for pregnancy interruption, and CDB-2914 (ulipristal acetate), licensed for managing AUB in women with leiomyomas and in a higher dose as an emergency contraceptive. In this article, we explore the clinical journey of SPRMs and the need for further interrogation of this class of drugs with the ultimate goal of improving women's quality of life.

An overview of spirooxindole as a promising scaffold for novel drug discovery

Introduction: Spirooxindole, a unique and versatile scaffold, has been widely studied in some fields such as pharmaceutical chemistry and synthetic chemistry. Especially in the application of medicine, quite a few compounds featuring spirooxindole motif have displayed excellent and broad pharmacological activities. Many identified candidate molecules have been used in clinical trials, showing promising prospects.Areas covered: This article offers an overview of different applications and developments of spirooxindoles (including the related natural products and their derivatives) in the process of drug innovation, including such as in anticancer, antimicrobial, anti-inflammatory, analgesic, antioxidant, antimalarial, and antiviral activities. Furthermore, the crucial structure-activity relationships, molecular mechanisms, pharmacokinetic properties, and main synthetic methods of spirooxindoles-based derivatives are also reviewed.Expert opinion: Recent progress in the biological activity profiles of spirooxindole derivatives have demonstrated their significant position in present-day drug discovery. Furthermore, we believe that the multidirectional development of novel drugs containing this core scaffold will continue to be the research hotspot in medicinal chemistry in the future.

Mifepristone Treatment in Pregnant Murine Model Induced Mammary Gland Dysplasia and Postpartum Hypogalactia

Mammary gland dysplasia and postpartum hypogalactia often occur in humans and in the livestock breeding industry. However, their underlying mechanisms are not clear yet. Mifepristone, which has a high affinity for progesterone (P4) and glucocorticoid receptors, was exploited here to induce the disorders of mammary gland development and lactation. Four strategies were devised for treating pregnant mice with mifepristone. In the first strategy, mice were administered 1.20 mg mifepristone/kg body weight (BW) on pregnancy day 4 (Pd4). In the second strategy, mifepristone was administered to mice twice, with 1.20 mg/kg BW on Pd4 and 0.40 mg/kg BW on Pd8. In the third strategy, mice were treated with a single dose of 0.40 mg mifepristone/kg BW on Pd8. In the fourth strategy, mice were administered 0.40 mg mifepristone/kg BW on Pd8 and 0.20 mg mifepristone/kg BW on Pd12. The results suggested that mifepristone administration at the dose of 1.20 mg/kg BW on Pd4 caused significant reduction in milk production on lactation day 1 (Ld1), Ld2, and Ld3, as assessed using a weigh-suckle-weigh assay. Mammary β-casein expression, milk yields, litter growth rates, gland structure, and serum concentrations of 17-β estrogen (E2), P4, prolactin (PRL), growth hormone (GH), corticosterone (CORT) and oxytocin (OT) as well as the receptors of these hormones were determined during pregnancy or lactation after performing the first (Pd4) strategy. The results demonstrated that mifepristone administration during early pregnancy decreased β-casein expression, milk yields and litter growth rates, induced fewer alveoli, enlarged alveolar lumina, and altered the levels of E2, P4, PRL, GH, CORT, and OT as well as the mRNA expression of these hormonal receptors during pregnancy or early lactation. The present study on pregnant mice treated with mifepristone offers an innovative murine model to study the mechanism underlying mammary gland dysplasia and postpartum hypogalactia.

Discovery of Vilaprisan (BAY 1002670): A Highly Potent and Selective Progesterone Receptor Modulator Optimized for Gynecologic Therapies

Progesterone plays an important role in the female reproductive system. However, there is also evidence that gynecologic disorders/diseases such as uterine fibroids and endometriosis are progesterone-dependent. Steroidal and non-steroidal selective progesterone receptor modulators (SPRMs) have shown potential for the treatment of such diseases. Steroidal SPRMs, including mifepristone and ulipristal acetate, have proven effective in clinical trials. However, several steroidal SPRMs containing a dimethylamino substituent have been associated with elevated liver enzymes in patients. An earlier drug discovery program identified lonaprisan as a highly selective SPRM that did not show drug-related change in liver enzyme activity. Building on data obtained from that work, here we describe the research program that culminated in the discovery of a novel steroidal SPRM, vilaprisan, which combines an extremely high potency with very favorable drug metabolism and pharmacokinetic properties. Vilaprisan has entered clinical development and is currently undergoing phase 3 clinical trials.

Investigational drugs for the treatment of endometriosis, an update on recent developments

INTRODUCTION

Endometriosis is a hormone-dependent benign chronic disease that requires a chronic medical therapy. Although currently available drugs are efficacious in treating endometriosis-related pain, some women experience partial or no improvement. Moreover, the recurrence of symptoms is expected after discontinuation of the therapies. Currently, new drugs are under intense clinical investigation for the treatment of endometriosis.

AREAS COVERED

This review aims to offer the reader a complete and updated overview on new investigational drugs and early molecular targets for the treatment of endometriosis. The authors describe the pre-clinical and clinical development of these agents.

EXPERT OPINION

Among the drugs under investigation, late clinical trials on gonadotropin-releasing hormone antagonists (GnRH-ant) showed the most promising results for the treatment of endometriosis. Aromatase inhibitors (AIs) are efficacious in treating endometriosis related pain symptoms but they cause significant adverse effects that limit their long-term use. New targets have been identified to produce drugs for the treatment of endometriosis, but the majority of these new compounds have only been investigated in laboratory studies or early clinical trials. Thus, further clinical research is required in order to elucidate their efficacy and safety in human.

Novel Non-steroidal Progesterone Receptor Ligands Based on m-Carborane Containing a Secondary Alcohol: Effect of Chirality on Ligand Activity

The progesterone receptor (PR) controls various physiological processes, including the female reproductive system, and nonsteroidal PR ligands are considered to be drug candidates for treatment of various diseases without significant adverse effects. Here, we designed and synthesized m-carborane-based secondary alcohols and investigated their PR-ligand activity. All the synthesized alcohols exhibited PR-antagonistic activity at subnanomolar concentration. Among them, alcohols having a small alkyl side chain and a 4-cyanophenyl group also exhibited PR-agonistic activity in a relatively high concentration range. Optical resolution of secondary alcohols having a methyl side chain was performed, and the PR-ligand activity and PR-binding affinity of the purified enantiomers were examined. The chirality of the secondary alcohol appears to have a more significant influence on PR-agonistic activity than on antagonistic activity.

Development of 6-arylcoumarins as nonsteroidal progesterone antagonists. Structure-activity relationships and fluorescence properties

Progesterone is involved in multiple physiological processes, including female reproduction, via binding to the progesterone receptor (PR). We have developed 6-arylcoumarins such as 5 and 6 as non-steroidal PR antagonists with receptor-binding-dependent fluorescence. In this study, we investigated the structure-activity relationships and fluorescence properties of coumarin derivatives bearing a heterocyclic aromatic moiety. Among these derivatives, 7c (IC₅₀: 34nM) and 10b (IC₅₀: 24nM) showed more potent PR-antagonistic activity than lead compounds 5 (IC₅₀: 500nM) and 6 (IC₅₀: 65nM) in alkaline phosphatase (AP) assay. Compound 9b showed solvent-dependent fluorescence intensity, exhibiting strong fluorescence in the presence of PR LBD only in buffer solution. On the other hand, 10b showed a solvent-dependent shift of the fluorescence maximum wavelength in the presence of PR LBD. These results indicate that 6-arylcoumarin will be a useful scaffold for PR antagonists and fluorescent probes targeting PR.

Development of 1,3-diphenyladamantane derivatives as nonsteroidal progesterone receptor antagonists

Nonsteroidal progesterone receptor (PR) full antagonists are needed as tools for elucidating the physiological functions of PR and as candidates for treatment of various diseases. We designed and synthesized 1,3-diphenyladamantane derivatives, and investigated their PR-antagonistic activity in comparison with our recently developed boron cluster-based PR antagonists. Among the synthesized adamantane derivatives, compound 9a exhibited the most potent PR-antagonistic activity (IC50: 25nM) and showed high binding affinity for the PR ligand-binding domain, comparable with that of the boron cluster-based PR antagonists. These results suggest that disubstituted adamantane, like the boron cluster m-carborane, is a promising hydrophobic pharmacophore for further structural development of nonsteroidal PR antagonists.

Antiprogestins in gynecological diseases

Antiprogestins constitute a group of compounds, developed since the early 1980s, that bind progesterone receptors with different affinities. The first clinical uses for antiprogestins were in reproductive medicine, e.g., menstrual regulation, emergency contraception, and termination of early pregnancies. These initial applications, however, belied the capacity for these compounds to interfere with cell growth. Within the context of gynecological diseases, antiprogestins can block the growth of and kill gynecological-related cancer cells, such as those originating in the breast, ovary, endometrium, and cervix. They can also interrupt the excessive growth of cells giving rise to benign gynecological diseases such as endometriosis and leiomyomata (uterine fibroids). In this article, we present a review of the literature providing support for the antigrowth activity that antiprogestins impose on cells in various gynecological diseases. We also provide a summary of the cellular and molecular mechanisms reported for these compounds that lead to cell growth inhibition and death. The preclinical knowledge gained during the past few years provides robust evidence to encourage the use of antiprogestins in order to alleviate the burden of gynecological diseases, either as monotherapies or as adjuvants of other therapies with the perspective of allowing for long-term treatments with tolerable side effects. The key to the clinical success of antiprogestins in this field probably lies in selecting those patients who will benefit from this therapy. This can be achieved by defining the genetic makeup required - within each particular gynecological disease - for attaining an objective response to antiprogestin-driven growth inhibition therapy.Free Spanish abstractA Spanish translation of this abstract is freely available at http://www.reproduction-online.org/content/149/1/15/suppl/DC1.

Medical treatment improves social behavior in a primate endometriosis model (Callithrix jacchus)

BACKGROUND

As endometriosis is known to be very painful in humans, therapeutic studies should consider pain-related aspects in experimental animals too. In a previous study, we found that common marmosets suffering from endometriosis show remarkable deviations in social behavior and cognitive tasks.

METHODS

Female marmosets with endometriosis undergoing medical treatment were tested vs. two control groups (healthy and endometriosis monkeys without treatment) concerning behavioral aspects, cognitive skills, and mobility.

RESULTS

The treated monkeys performed significant more social and self-grooming, comfort behavior and were more active than the untreated endometriosis monkeys. The treated marmosets even returned to equal levels as their healthy conspecifics. Cognitive and mobility tests revealed no significant differences.

CONCLUSIONS

A beneficial effect of the applied endometriosis medication on behavioral impairments could be obtained. Including such measurements in therapeutic research contributes to aspects of animal welfare and pain-relieving potential of the tested compound.

Mifepristone for uterine fibroids

BACKGROUND

Uterine fibroids are the most common benign uterine tumours present in women of reproductive age. Mifepristone (RU-486) competitively binds and inhibits progesterone receptors. Studies have suggested that fibroid growth depends on the sexual steroids. Mifepristone has been shown to decrease fibroid size. This review summarises the effects of mifepristone treatment on fibroids and the associated adverse effects as described in randomised controlled trials.

OBJECTIVES

To determine the efficacy and safety of mifepristone for the management of uterine fibroids in pre-menopausal women.

SEARCH METHODS

We searched the specialised register of the Cochrane Menstrual Disorders and Subfertility (Cochrane Menstrual Disorders and subfertility Review Group), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 4), MEDLINE, EMBASE, PsycINFO, and CINAHL (to November 2011). We handsearched a number of journals, and searched reference lists, databases of ongoing trials and the Internet. There were no language restrictions.

SELECTION CRITERIA

Only truly randomised controlled trials of mifepristone versus other forms of medical therapy or placebo in pre-menopausal women with confirmed uterine fibroids were included.

DATA COLLECTION AND ANALYSIS

Four authors independently extracted data and assessed trial quality. Data were analysed using the Peto odds ratios (OR) for dichotomous data and the weighted mean differences for continuous data, with 95% confidence intervals (CI). Meta-analyses were performed using the fixed-effect model.

MAIN RESULTS

Three studies involving 112 participants were included. Comparison interventions included different dosages of mifepristone, placebo and vitamin B tablets. There is evidence that treatment with mifepristone relieves heavy menstrual bleeding compared with placebo (Peto OR 17.84; 95% CI 6.72 to 47.38; 2 RCTs, 77 women, I(2) = 0%). Three studies (Bagaria 2009; Engman 2009; Fiscella 2006) were included in the meta-analysis of this comparison. There was no evidence of an effect of mifepristone on the fibroid volume (standardised mean difference (SMD) -0.02; 95% CI -0.38 to 0.41; 99 women). Two studies (Bagaria 2009; Fiscella 2006) were included in the meta-analysis of this comparison. There was no evidence of an effect of mifepristone on uterine volume (mean difference (MD) -77.24; 95% CI -240.62 to 86.14; 72 women). The pooled data suggest an increased adverse event (abnormal endometrial histology) in the mifepristone group compared to placebo (OR 31.65; 95% CI 4.83 to 207.35; 2 RCTs; 54 women; I(2) = 0%). Only one study (Bagaria 2009) reported endometrial hyperplasia at the end of the therapy (12/19 women in the mifepristone group versus 0/16 in the placebo group; OR 55.0; 95% CI 2.86 to 105.67). Engman 2009 found a significantly higher rate of cystic glandular dilatation in women in the mifepristone group (5/8 women biopsied) compared with the placebo group (1/11 women biopsied) (OR 16.67; 95% CI 1.36 to 204.03). One study (Fiscella 2006) suggested significant improvements (P < 0.001) for specific quality of life outcomes.

AUTHORS' CONCLUSIONS

Mifepristone reduced heavy menstrual bleeding and improved fibroid-specific quality of life. However, it was not found to reduce fibroid volume. Further well-designed, adequately powered RCTs are needed before a recommendation can be made on the use of mifepristone for the treatment of uterine fibroids.

Pharmacology and clinical use of sex steroid hormone receptor modulators

Sex steroid receptors are ligand-triggered transcription factors. Oestrogen, progesterone and androgen receptors form, together with the glucocorticoid and mineralocorticoid receptors, a subgroup of the superfamily of nuclear receptors. They share a common mode of action, namely translating a hormone-i.e. a small-molecule signal-from outside to changes in gene expression and cell fate, and thereby represent "natural" pharmacological targets.For pharmacological therapy, these receptors have originally been addressed by hormones and synthetic hormone analogues in order to overcome pathologies related to deficiencies in the natural ligands. Another major use for female sex hormone receptor modulators is oral contraception, i.e. birth control.On the other side, blocking the activity of sex steroid receptors has become an established way to treat hormone-dependent malignancies, such as breast and prostate cancer.In this review, we will discuss how the experience gained from the classical pharmacology of these receptors and their molecular similarities led to new options for the treatment of gender-specific diseases and highlight recent progress in medicinal chemistry of sex hormone-modulating drugs.

Use of mifepristone to treat endometriosis: a review of clinical trials and trial-like studies conducted in China

China was the first country in the world that approved mifepristone (RU-486) for abortion. A total of 6 years after the report published in the Western world indicated that mifepristone may also be effective in treating endometriosis, the first paper on the same topic was published in China in 1997. Since then, over 160 studies on this topic have been published in China. We retrieved 104 papers on clinical trials and trial-like studies conducted in China evaluating the use of mifepristone to treat endometriosis that were published in the last 11 years. We found that the quality of these studies is well below an acceptable level, making it difficult to judge whether mifepristone is truly efficacious. There are intriguing signs that these studies, as a whole, have serious anomalies. The areas that are glaringly deficient are informed consent, choice of outcome measures, the evaluation of outcome measures, data analysis and randomization. The uniformly low quality is disquieting, given the large quantity of studies, the enormous amount of resource and energy put into these studies and, above all, the weighty issue of treatment efficacy that concerns each and every patient with endometriosis. Equally disquieting are the low-quality repetition, the absence of a critical, systematic review on the subject, the lack of suggestions for multicenter clinical trials and the seemingly unnecessary duplication of clinical trials without due informed consent. In view of this, it may be time to institute changes in attitude and practice, and to change education and training programs in the methodology of clinical trials in obstetrics and gynecology research in China.

CDB-4124, a progesterone receptor modulator, inhibits mammary carcinogenesis by suppressing cell proliferation and inducing apoptosis

CDB-4124 (Proellex or telapristone acetate) is a modulator of progesterone receptor (PR) signaling, which is currently employed in preclinical studies for prevention and treatment of breast cancer and has been used in clinical studies for treatment of uterine fibroids and endometriosis. Here we provide evidence for its action on steroid hormone-signaling, cell cycle-regulated genes and in vivo on mammary carcinogenesis. When CDB-4124 is given to rats at 200 mg/kg for 24 months, it prevents the development of spontaneous mammary hyperplastic and premalignant lesions. Also, CDB-4124 given as subcutaneous pellets at two different doses suppressed, dose dependently, N-methyl-N-nitrosourea (MNU)-induced mammary carcinogenesis. The high dose (30 mg, over 84 days) increased tumor latency from 66 ± 24 days to 87 ± 20 days (P < 0.02), decreased incidence from 85% to 35% (P < 0.001), and reduced multiplicity from 3.0 to 1.1 tumors/animal (P < 0.001). Tumor burden decreased from 2.6 g/animal to 0.26 g/animal (P < 0.01). CDB-4124 inhibited cell proliferation and induced apoptosis in MNU-induced mammary tumors, which correlated with a decreased proportion of PR(+) tumor cells and with decreased serum progesterone. CDB-4124 did not affect serum estradiol. In a mechanistic study employing T47D cells we found that CDB-4124 suppressed G(1)/G(0)-S transition by inhibiting CDK2 and CDK4 expressions, which correlated with inhibition of estrogen receptor (ER) expression. Taken together, these data indicate that CDB-4124 can suppress the development of precancerous lesions and carcinogen-induced ER(+) mammary tumors in rats, and may have implications for prevention and treatment of human breast cancer.

A novel mifepristone-loaded implant for long-term treatment of endometriosis: in vitro and in vivo studies

The objective of this study was to prepare a novel mifepristone-loaded PCL/Pluronic F68 implant to achieve long-term treatment of endometriosis. PCL/Pluronic F68 compound (90/10, w/w) with viscosity average molecular weight of 65,000 was successfully synthesized. The end-capped Pluronic F68 was incorporated in PCL matrixes as molecular dispersion without forming a copolymer. The mifepristone-loaded implant made of PCL/Pluronic F68 compound was a cylindrical capsule with an outer diameter of 2.5mm and an inner diameter of 2.2mm. The surface of PCL/Pluronic F68 compound appears porous because Pluronic F68 which is water soluble could leach out due to the water phase. Drug loading of 0.75-, 1.5- and 3.0-cm length implants was 3.05+/-0.18, 6.06+/-0.41 and 11.87+/-0.39mg, respectively. A sustained mifepristone release rate without obvious initial burst and later decline over a period of 180d was observed. The cumulative drug release showed a linear relationship with time, indicating that mifepristone release from the implants followed zero-order kinetics (R(2)>0.99). The data showed that the C(max) and AUC(0-inf) were proportional to imlant length and dose, and all groups reached plasma C(max) at about the same time (approximately 7d) and had similar T(1/2) (approximately 150d) and MRT (approximately 220d). There were obvious inhibitory effects on the growth of endometrial explants in Wister rats in a dose-dependent manner after administration of mifepristone-loaded implants with implant length from 1.5 to 9.0cm for 1-3 months. However, mifepristone-loaded implants with implant length of 12.0cm had no better inhibitory effects on the growth of endometrium when compared with the implants with implant length of 9.0cm (P>0.05). In conclusion, subcutaneous implantation of mifepristone-loaded PCL/Pluronic F68 capsules was proven an effective means for long-term treatment of chronic endometriosis.

Estradiol and progesterone-induced slowing of gonadotropin-releasing hormone pulse frequency is not reversed by subsequent administration of mifepristone

Subsequent to suppression of LH (GnRH) pulse frequency by progesterone (P) and estradiol (E(2)), LH pulse frequency remains slow for 7 days after P withdrawal if mid-luteal E(2) concentrations are maintained. This may reflect an ability of E(2) to potentiate the suppressive effects of low P levels. We explored this notion in a similar experimental paradigm by administering a P-receptor antagonist (mifepristone) after P withdrawal while continuing E(2). Studies were performed in seven ovulatory, non-obese women. Transdermal E(2) (0.2 mg/day) and oral micronized P (100 mg every 8 h) were started within 24 h of the LH surge and continued for 10 days. Subjects then underwent a 13-h blood sampling protocol for determination of LH pulse characteristics and various hormone concentrations. Oral P was then discontinued, and oral mifepristone (50, 100, or 200 mg daily) and transdermal E(2) (0.2 mg/day) were administered for 7 days, after which the above sampling protocol was repeated. Results with all mifepristone doses were similar and therefore pooled. Mean LH, LH amplitude, and mean FSH markedly decreased after 7 days of mifepristone, but LH pulse frequency did not change (3.3 +/- 1.5 vs. 2.4 +/- 1.5 pulses/13 h). Prolactin and androstenedione increased between the first and second admissions, with no changes in E(2), cortisol, testosterone, or DHEAS. In conclusion, blockade of P action by mifepristone does not reverse a suppressed LH pulse frequency within 7 days when E(2) concentrations are maintained, suggesting that P withdrawal alone may not explain the luteal-follicular increase of GnRH pulse frequency.

New drugs in development for the treatment of endometriosis

Endometriosis is a common and enigmatic disease causing pelvic pain and infertility. Current treatment is mainly based on the use of surgery and ovarian suppressive agents. There is in particular the need for new therapeutic options able to allow a normal menstrual cycle to occur and also consent pregnancy. In the present review, we aimed to give a concise and practical overview in order to allow the clinician to clearly understand the level of development of these drugs. We have presented only treatments supported by in vivo researches with a special attention to studies in humans. Results show appealing new possibilities are emerging from agents counteracting the endometriosis-associated inflammation. Recent data also suggests that there is still the opportunity to refine the use of already available agents.

Investigational developments for the treatment of progesterone-dependent diseases

BACKGROUND

Clinical evidence has shown that conditions such as uterine fibroids, endometriosis and breast cancer are progesterone-dependent diseases. Therefore, progesterone receptor (PR) antagonists and selective PR modulators (SPRMs) are under development for the treatment of these conditions. However, the first PR antagonists that became available exhibit insufficient selectivity or tolerability for the chronic administration required to treat these conditions. Despite initial setbacks, development of second-generation PR antagonists with better selectivity continues forward.

OBJECTIVE

In this review we would like to summarise prospects for using PR antagonists for the treatment of uterine fibroids, endometriosis and breast cancer, and to give an overview of the development of new steroidal and non-steroidal PR antagonists.

METHOD

Available preclinical and clinical data and publications have been reviewed with the focus on scientific background and use in the three mentioned indications.

RESULTS/CONCLUSION

Preclinical and clinical evidence demonstrated that PR antagonists and SPRMs are effective for the treatment of progesterone-dependent diseases. Future development will demonstrate if they can become important drugs.

Treatment strategies for endometriosis

BACKGROUND

Endometriosis is a common chronic disease that causes symptoms of pain and infertility. The pain syndrome can be quite incapacitating. The pain symptoms usually originate in the reproductive organs but can also involve the urinary or intestinal tracts if endometriosis implantation has occurred there. The presentation and physical appearance of endometriosis is extremely variable and can be characterized by a chronic intraperitoneal inflammatory process and adhesions. The only definitive diagnostic technique is laparoscopy.

OBJECTIVE

To review current literature on the treatment strategies for endometriosis.

METHODS

Review of Pubmed, Cochrane database and Medline for current review articles and studies regarding the current treatment strategies for endometriosis.

RESULTS

Initial treatment is surgical or medical. Medical therapy is often used as a first-line therapy and can also be used in conjunction with those patients who undergo surgical therapy for pain. No medical therapy has proven effective for infertility. Medical therapy consists mostly of hormonal suppressive therapy in which the medication causes a downregulation of the hypothalamus-pituitary-ovarian pathway. Non-steroidal anti-inflammatory drugs and oral contraceptives are often used as an initial approach even without a definitive diagnosis. Progestins, such as oral norethindrone and depot medroxyprogesterone, are effective while using them but have a high recurrence rate. The norgestrol intrauterine device is also quite effective at relieving pain associated with endometriosis, especially pain arising during menses as well as from lesions in the rectovaginal tissue. Gonadotropin-releasing hormone agonists induce a pseudomenopausal state and have significant side effects, such as hot flashes and genital atrophy. 'Add-back' therapy with a progestin has been shown to relieve most of these drug related symptoms. Gonadotropin-releasing hormone agonists are also very effective at relieving symptoms of pain during treatment but are also associated with a high recurrence rate. New drug therapies that are under investigation are aromatase inhibitors and immunomodulators. Furthermore, new delivery systems are being investigated that may also improve the patient response.

Novel phosphorus-containing 17beta-side chain mifepristone analogues as progesterone receptor antagonists

A novel series of steroidal compounds were designed and synthesized with various phosphorus-containing groups on the 17beta-side chain as progesterone receptor antagonists. The structure-activity relationships of these compounds are discussed. Selected compounds were tested in an rat progesterone-sensitive assay. Some of these compounds are more potent than mifepristone, with a better selectivity profile in differentiating progesterone receptor from glucocorticoid receptor.

Medical management of endometriosis

Current approved medical therapies for endometriosis rely on drugs that suppress ovarian steroids and induce a hypoestrogenic state, which determines the atrophy of the ectopic endometrium. Gonadotropin-releasing hormone analogs such as danazol, progestogens and estrogen-progestin combinations have all proven effective in relieving pain and reducing the extent of endometriotic implants. However, symptoms often recur after discontinuation of therapy and hypoestrogenism-related side effects limit the long-term use of most medications. Recently, knowledge of the pathogenesis of endometriosis, particularly at the molecular level, has grown substantially, providing a rational basis for the development of new drugs with precise targets that may be safely administered over the long term.

Management of patients receiving long-term treatment with mifepristone

OBJECTIVE

To determine clinical side effects and biochemical and hematological abnormalities in patients with nonresectable meningioma on long-term mifepristone (RU 486) therapy.

DESIGN

Long-term mifepristone administration in patients with meningioma.

SETTING

Outpatient clinic of a university hospital.

PATIENT(S)

Sixteen women and 9 men aged 22-80 years with nonresectable meningioma.

INTERVENTION(S)

Mifepristone (200 mg daily). One patient received treatment for more than 13 years; six received treatment for 10-12 years; five received treatment for 4-9 years; eight received treatment for 1-4 years; and the remainder received treatment for 4-10 months.

MAIN OUTCOME MEASURE(S)

Evaluation of side effects and of hematological and biochemical abnormalities.

RESULT(S)

Fatigue was observed in 22 of 25 patients. Endometrial hyperplasia occurred in one premenopausal woman and one postmenopausal woman. Another two women had endometrial thickening without hyperplasia. There were no consistent abnormalities in liver or renal function or in any other biochemical or hematological parameters. One subject (on long-term dexamethasone) developed hypoadrenalism, which responded to treatment.

CONCLUSION(S)

Mifepristone can be administered for prolonged periods. Ultrasound should be performed if irregular vaginal bleeding occurs. In asymptomatic women, it should be performed annually. If endometrial thickening is observed, then endometrial biopsy is recommended. Because biochemical hypothyroidism has been reported during long-term mifepristone therapy, thyroid function tests should be performed annually.

Future Perspectives in the Medical Treatment of Endometriosis

In the last few years, our understanding of the pathogenesis of endometriosis at the cellular and molecular levels has improved significantly. This may give us the opportunity to use new, specific agents for the treatment of this disorder. Despite the effectiveness of the available treatments, novel therapeutic strategies may improve our ability to eliminate endometriotic lesions when present and to prevent the recurrence of endometriosis after surgical treatment. This review focuses on the new, experimental approaches to the medical treatment of endometriosis and its symptoms. The blockage of aromatase activity in endometriotic lesions with an aromatase inhibitor may represent a new step in the medical treatment of endometriosis. Preliminary clinical studies have demonstrated the efficacy of third-generation nonsteroidal aromatase inhibitors (ie, anastrozole and letrozole) in reducing the intensity of pain symptoms associated with the presence of endometriosis. The new selective progesterone receptor modulators may represent a valid hormonal treatment option. Therapeutic manipulation of the immune system through TNFalpha inhibitors may be beneficial in women with endometriosis. New pharmaceutical agents affecting inflammation, angiogenesis, and matrix metalloproteinase activity may prevent or inhibit the development of endometriosis. Further clinical trials may determine if these new therapies are superior to current medical treatment strategies for endometriosis.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians Learning.

OBJECTIVES

After completion of this article, the reader should be able to describe the new experimental medical treatments of endometriosis, state that the clinical use of nonsteroidal aromatase inhibitors for endometriosis appears to be efficacious but is based on preliminary clinical data, and recall that the drugs used for endometriosis in the future may include manipulation of the immune system.

The putative tumor suppressor deleted in malignant brain tumors 1 is an estrogen-regulated gene in rodent and primate endometrial epithelium

Deleted in malignant brain tumors 1 (DMBT1) is a candidate suppressor of malignancies of the brain, lung, gut, and breast. We have been studying gene expression in the uterus in the presence of estrogens and their antagonists. Here, we show that DMBT1 RNA levels are robustly increased by estrogen treatment in the uteri of ovariectomized monkeys and rats. In monkeys, the progestin antagonist mifepristone inhibits estrogen-dependent uterine proliferation. As determined by a microarray experiment and quantitative analysis of RNA levels, mifepristone inhibited estrogenic induction of DMBT1. DMBT1 was not expressed in intact monkeys that were treated with a gonadotropin agonist to suppress steroidogenesis. An in vitro transfection study with human DMBT1 promoter constructs showed that an Alu site approximately 3000 nucleotides upstream of the gene mediates estrogenic regulation. Surprisingly, the estrogen antagonists tamoxifen, raloxifene, and ICI 182,780 also induced gene expression via this Alu site. Rodents represent a more convenient model system for studying uterine biology than monkeys. In rats, uterine DMBT1 RNA levels were dramatically up-regulated by estrogen. Consistent with the transfection study, tamoxifen and raloxifene increased DMBT1 RNA levels in vivo, but ICI 182,780 inhibited an estrogen-induced increase. Immunohistochemical studies showed that DMBT1 is specifically induced in glandular and luminal epithelia of the rat endometrium. Our experiments establish that DMBT1 is an estrogen-responsive gene with a possible role in endometrial proliferation or differentiation, and they have implications for the putative tumor suppressive and mucosal protective functions of DMBT1 in the uterus.

[Present and potential uses of mifepristone in gynecology, obstetrics and other medical specialties]

Mifepristone, a derivative of norethindrone, a first generation synthetic progestative, has a very potent antiprogestative activity and to a lesser degree antiandrogenic and antiglucocorticoid activities. This action makes it potentially useful in the treatment of multiple hormone dependent diseases in obstetrics-gynecology as well as in a variety of medical specialties such as neurology, ophthalmology, and oncology. Nevertheless, the label of abortive pill has incited numerous ethical and political debates concerning the permission to market this drug, and this has contributed to the delay in the assessment of the potential indications of mifepristone. Largely under-utilized in practice despite its increasing theoretical benefit, clinical studies should now de conducted. Thus, based on an international review of literature during the last ten years, we have shed light on the present and potential indications of mifepristone in medical practice.

New medical treatments for endometriosis

The medical treatment of endometriosis has long centered upon producing a hypoestrogenic environment by producing pituitary suppression or a progestin-dominant environment. However, as more is uncovered regarding the pathogenesis and pathophysiology of this disease, more targeted therapies can be developed. Current research has focused upon medications designed to attack specific aspects of the development and maintenance of endometriosis. These include progesterone receptor modulators, gonadotropin releasing hormone (GnRH) antagonists, aromatase inhibitors, tumor necrosis factor alpha (TNF-alpha) inhibitors, angiogenesis inhibitors, matrix metalloproteinase inhibitors, pentoxifylline (and other general immune modulators), and estrogen receptor beta agonists. It is hoped that this new wave of medications will improve the response to medical therapy for this disorder.

Medical management of endometriosis-associated pain

In the coming years, basic science research into the mechanisms of endometriosis development and persistence almost certainly will open new avenues for treatment. A wide armamentarium of medical therapies already exists, however. The efficacy of most of these methods in reducing endometriosis-associated pain is well established. The choice of which to use depends largely on patient preference after an appropriate discussion of risks, side effects, and cost. Typically, oral contraceptives and NSAIDs are first-line therapy because of their low cost and mild side effects (Box 6). Because of its greater potential for suppressing endometrial development, consideration should be given to prescribing a low-dose monophasic oral contraceptive continuously. If adequate relief is not obtained or if side effects prove intolerable, consideration should be given to the use of progestins (oral, intramuscular, or IUD) or a GnRH agonist with immediate add-back therapy. Progestins are less expensive, but GnRH agonists with add-back may be better tolerated. If none of these medications proves beneficial or if side effects are too pronounced, then repeat surgery is warranted. The surgery may have analgesic value and serves to reconfirm the diagnosis. Finally, if endometriosis is identified at the time of surgery, then consideration should be given to prescribing medical therapy postoperatively.

Effect of long-term treatment with low-dose mifepristone on the endometrium

BACKGROUND

Mifepristone in low daily doses has contraceptive potential by inhibiting ovulation and menstruation. Because follicular development is maintained, the endometrium is exposed to estrogen for prolonged periods unopposed by progesterone.

METHODS

Endometrial biopsies were collected from 90 women in Edinburgh and Shanghai before (late proliferative) and 60 and 120 days after taking 2 or 5 mg mifepristone per day for 120 days.

RESULTS

Ovulation and menstruation were inhibited in >90% of cycles and estrogen production was similar to that observed during the follicular phase of the control cycle. By 120 days, endometrial thickness increased significantly in women in Edinburgh but decreased in Shanghai. Endometrial histology showed inactive proliferative or cystic changes with dense stroma. There was a significant decrease in markers of proliferation, i.e. mitotic index and Ki67 staining. There were no pregnancies in a total of 200 women-months in 50 sexually active women who used no other method of contraception.

CONCLUSIONS

We confirm that ovulation and menstruation were suppressed in the majority of cycles and there was asynchrony between ovarian activity and endometrial histology, which showed no signs of hyperplasia or atypia. These preliminary data suggest that daily low-dose mifepristone is potentially a safe estrogen-free contraceptive pill which has the added health benefit of amenorrhoea.

New progesterone receptor antagonists: 3,3-disubstituted-5-aryloxindoles

A new series of 3,3-disubstituted-5-aryloxindoles has been synthesized and evaluated for progesterone receptor antagonist (PR) activity in a T47D cell alkaline phosphatase assay and for their ability to bind PR in competition binding studies. In this communication, the synthesis and structure-activity relationships (SARs) of various 3,3-substituents are discussed where it is clear that small alkyl and spiroalkyl groups are required to achieve better PR antagonist activity.

A benefit-risk assessment of medical treatment for uterine leiomyomas

The growth of a uterine leiomyoma growth stops and regresses after the menopause suggesting that leiomyoma growth is dependent on ovarian steroids. Therefore, estrogen has received much attention as the major factor responsible for the development of uterine leiomyomas, but progesterone also plays an important role in development of this disease. Cytogenetic analyses of resected samples has revealed that about 40 to 50% of leiomyomas show karyotypically detectable chromosomal abnormalities. Gonadotrophin releasing hormone (GnRH) agonists exert their action through the suppression of endogenous gonadotrophins and gonadal steroid secretion. Significant reductions of uterine/leiomyoma volume under GnRH agonist therapy has been reported in several studies. However, the leiomyoma generally returns to its pretreatment volume within a few months after discontinuation of the GnRH agonist. To minimise the adverse effects of hypoestrogenism during GnRH agonist treatment, add back therapy can be used (estrogen-progestin, progestin alone and recently tibolone). Antiprogestins have a potential clinical utility in uterine leiomyomas. Mifepristone is a synthetic steroid with both antiprogesterone and antiglucocorticoid activities, that may have an inhibitory effect on growth of leiomyoma. Danazol is an isoxazole of 17beta-ethinyl testosterone, a synthetic steroid, which has a suppressive effect on sex hormone binding globulin concentrations, resulting in efficacy in the short-term treatment of uterine leiomyomas. Gestrinone is a tri-enic steroid with antiestrogen and antiprogesterone properties and has been shown to reduce uterine volume and stop bleeding. Growth factors play a relevant role on the pathophysiology of uterine leiomyoma and probably the inhibition of the action of growth factors on the myometrium will be the basis for future therapy. A number of agents are under investigation for treating uterine leiomyoma. Agents developed from increasing genetic knowledge of this condition could represent, in the next few years, new trends in the medical treatment of uterine leiomyomas.

An open label trial of C-1073 (mifepristone) for psychotic major depression

BACKGROUND

The rationale for treating patients with psychotic major depression (PMD) with glucocorticosteroid receptor (GR) antagonists is explained.

METHODS

Thirty patients with PMD, with Hamilton Rating Scale for Depression (HAMD-21) scores of 18 or greater, were assigned in an open label trial to receive 50 mg, 600 mg, or 1200 mg of mifepristone for 7 days.

RESULTS

All the subjects completed the protocol; there were no dropouts. Side effects were mild and sporadic. Of 19 subjects in the combined 600- and 1200-mg group, 13 had a 30% or greater decline in their Brief Psychiatric Rating Scale (BPRS) scores, compared with 4 of 11 in the 50-mg group. In the 600- and 1200-mg group, 12 of 19 subjects showed a 50% decline in the BPRS positive symptom subscale, a more sensitive index for the symptoms seen in PMD, compared with 3 of 11 in the 50-mg group; 8 of 19 subjects in the 600- and 1200-mg group had a 50% decline in the HAMD-21, compared with 2 of 11 in the 50-mg group.

CONCLUSIONS

These results suggest that short term use of GR antagonists may be effective in the treatment of psychotic major depression and that further blinded studies are warranted.

Identification and characterization of novel estrogen receptor-beta-sparing antiprogestins

The steroid hormones estrogen and progesterone together regulate the development and maintenance of the female reproductive system. The actions of these two hormones are mediated by their respective nuclear receptors located within overlapping cell populations in target organs. The molecular mechanism of action of these two hormones has been defined to a large extent using estrogen receptor (ER) and progesterone receptor (PR) antagonists. In the case of ER, the available antagonists are highly receptor selective. With respect to PR, however, the available antiprogestins also interact with the receptors for glucocorticoids, mineralocorticoids, and androgens. Whereas these cross-reactivities can usually be managed in studies of female reproductive function, it is the recent demonstration that RU486 is an effective antagonist of the beta-isoform of ER that suggested the need for more selective antiprogestins. In this study, we used cell-based transcriptional assays combined with screens using coactivator peptide analogs to identify two novel classes of antiprogestins that distinguish themselves from the antiprogestin RU486 in the manner they interact with PR. One class exhibits the characteristics of a pure antiprogestin in that its members bind to the receptor and induce a conformational change that prevents the presentation of two potential coactivator binding surfaces on the protein. The second class of compounds distinguish themselves from RU486 in that they are ERbeta sparing. When tested in vivo the ER-sparing antiprogestins were as effective as RU486 in suppressing superovulation. It is anticipated that the availability of these new antiprogestins will advance the studies of PR pharmacology in a manner similar to how the availability of selective ER modulators has helped the study of ER action.

Effect of mifepristone on estrogen and progesterone receptors in human endometrial and endometriotic cells in vitro

OBJECTIVE

To investigate the expressions of estrogen (E) receptor and progesterone (P) receptor in human eutopic and ectopic endometrium and the effect of mifepristone (RU486) on them.

DESIGN

Prospective study.

SETTING

University hospital.

PATIENT(S)

Twenty-two patients with ovarian endometriosis and 13 patients with uterine leiomyoma were recruited.

INTERVENTION(S)

Samples of ovarian endometrioma cyst tissue and endometrium were obtained from the 22 patients. A sample of endometrium was obtained from the 13 patients.

MAIN OUTCOME MEASURE(S)

Expressions of E and P receptors were determined using immunocytochemical method.

RESULT(S)

P receptor expression in endometrial epithelial cells with endometriosis was significantly higher than that without endometriosis in the early secretory phase. Estrogen receptor and epithelial P receptor expressions in endometriotic cells were significantly lower than those of endometrial cells during the proliferative phase, similar with the latter during the early secretory phase and significantly higher during the late secretory phase. RU486 down-regulated the expressions of E and P receptors in both the eutopic and the ectopic endometrial cells, and in some cases this down-regulating effect was more apparent when the concentration of RU486 was higher.

CONCLUSION(S)

Different steroid receptor expressions indicate different hormonal regulation between endometriotic and endometrial cells. The down-regulating effect on E and P receptors may be one of the therapeutic mechanisms of RU486 on endometriosis.

Potent nonsteroidal progesterone receptor agonists: synthesis and SAR study of 6-aryl benzoxazines

Novel 6-aryl benzoxazines were prepared and examined as progesterone receptor (PR) modulators. In contrast to the structurally related 6-aryl dihydroquinoline PR antagonists, the 6-aryl benzoxazines were potent PR agonists. Compounds 4e, 5b, and 6a with the 2,4,4-trimethyl-1,4-dihydro-2H-benzo[d][1,3]oxazine core were the most potent PR agonists in the series with sub-nanomolar activities (EC(50) 0.20-0.35nM). Compound 6a was more potent than progesterone (P4) in the in vivo decidualization assay in an ovariectomized female rat model by subcutaneous administration with an ED(50) of 1.5mg/kg (vs 5.62mg/kg for P4).