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

The emerging role of progesterone receptor modulators in breast physiology, cancer prevention and treatment

BACKGROUND

Progesterone is critical for cyclic breast changes and breast cancer carcinogenesis. The commercially available progesterone receptor modulators (PRMs), ulipristal acetate (UPA) and mifepristone, have been utilised for their antiprogestogen effect in gynaecology. Administration of these medicines appears to induce favourable cellular and radiographic changes in the breast.

METHODS

This is a narrative review of the basic science, translational and clinical trials utilising UPA and mifepristone for breast health. It integrates historical and recent trials from around the world.

RESULTS

PRMs have shown promise in decreasing molecular markers of carcinogenesis in BRCA1 carriers. Outside of genetic cancer risk, PRMs decrease background parenchymal enhancement on breast magnetic resonance imaging and could be developed as a personalised protocol for breast cancer screening. Although there was limited efficacy of antiprogestogens in progression-free survival for people with breast cancer, there may be a role as neoadjuvant therapy prior to surgical resection.

CONCLUSIONS

UPA and mifepristone have the potential to revolutionise breast cancer prevention, screening and treatment. As protocols emerge, gynaecologists will be on the front lines as regards both identifying patients who may benefit from these medications and serving as interdisciplinary support in accessing these medicines.

Selective progesterone receptor modulators for the treatment of dysmenorrhea: an update

INTRODUCTION

Dysmenorrhea is a painful symptom associated with uterine contractions and menstrual bleeding and is treated by administering analgesic drugs. Since progesterone receptors (PRs) have a major role in regulating uterine tissues (myometrium and endometrium) physiology, oral contraceptives are used off-label for treating primary or secondary dysmenorrhea. The development of selective progesterone receptor modulators (SPRMs), a class of synthetic steroids with agonistic, antagonistic, or mixed effects in targeting PRs in different tissues, stimulated their possible clinical use for treating secondary dysmenorrhea related to uterine diseases (endometriosis, adenomyosis, uterine fibroids).

AREAS COVERED

The present review examines the development of the clinical trials and observational studies done with the different SPRMs for the treatment of dysmenorrhea in patients with uterine diseases.

EXPERT OPINION

Mifepristone, telapristone acetate and vilaprisan have antagonistic activity on PRs, whereas ulipristal acetate and asoprisnil have both potent antagonist and partial agonist effects.Since no studies have been done on primary dysmenorrhea, the different SPRMs have been evaluated in the treatment of endometriosis, adenomyosis and uterine fibroid-related dysmenorrhea.

Design, Synthesis, and Evaluation of B-(Trifluoromethyl)phenyl Phosphine-Borane Derivatives as Novel Progesterone Receptor Antagonists

We previously revealed that phosphine-boranes can function as molecular frameworks for biofunctional molecules. In the present study, we exploited the diversity of available phosphines to design and synthesize a series of B-(trifluoromethyl)phenyl phosphine-borane derivatives as novel progesterone receptor (PR) antagonists. We revealed that the synthesized phosphine-borane derivatives exhibited LogP values in a predictable manner and that the P-H group in the phosphine-borane was almost nonpolar. Among the synthesized phosphine-boranes, which exhibited PR antagonistic activity, B-(4-trifluoromethyl)phenyl tricyclopropylphosphine-borane was the most potent with an IC50 value of 0.54 μM. A docking simulation indicated that the tricyclopropylphosphine moiety plays an important role in ligand-receptor interactions. These results support the idea that phosphine-boranes are versatile structural options in drug discovery, and the developed compounds are promising lead compounds for further structural development of next-generation PR antagonists.

Current and Emerging Treatment Options for Uterine Fibroids

Uterine fibroids are the most common benign neoplasm of the female reproductive tract in reproductive age women. Their prevalence is age dependent and can be detected in up to 80% of women by the age of 50 years. Patients affected by uterine fibroids may experience a significant physical, emotional, social, and financial toll as well as losses in their quality of life. Unfortunately, curative hysterectomy abolishes future pregnancy potential, while uterine-sparing surgical and radiologic alternatives are variously associated with reduced long-term reproductive function and/or high tumor recurrence rates. Recently, pharmacological treatment against uterine fibroids have been widely considered by patients to limit uterine fibroid-associated symptoms such as heavy menstrual bleeding. This hormonal therapy seemed effective through blocking the stimulatory effects of gonadal steroid hormones on uterine fibroid growth. However, they are contraindicated in women actively pursuing pregnancy and otherwise effective only during use, which is limited because of long-term safety and other concerns. Accordingly, there is an urgent unmet need for safe, durable, and fertility-compatible non-surgical treatment options for uterine fibroids. In this review article, we cover the current pharmacological treatments for uterine fibroids including their comparable efficacy and side effects as well as emerging safe natural compounds with promising anti-uterine fibroid effects.

Clinical Efficacy, Pharmacokinetics, and Safety of the Available Medical Options in the Treatment of Endometriosis-Related Pelvic Pain: A Scoping Review

BACKGROUND

In this scoping review, we sought to identify published studies evaluating the drugs currently used in the treatment of endometriosis-related pelvic pain, with reflection on their chemical properties, pharmacokinetics, safety profile, and clinical efficacy.

METHODS

A literature search was conducted with the use of the PubMed and EMBASE electronic databases, focusing on identifying articles published in English between January 1990 and 2023.

RESULTS

Based on the included studies, current therapy options for the treatment of endometriosis-related pain identified and reviewed in this article were: (1) non-steroidal anti-inflammatory drugs; (2) combined oral contraceptive (COCs); (3) progestins; (4) gonadotropin-releasing hormone agonists and antagonists; (5) aromatase inhibitors (AIs); (6) selective estrogen and progesterone receptor modulators; and (7) levonorgestrel-intrauterine device.

CONCLUSIONS

Based on the published evidence, clinicians should consider NSAIDs, COCs, and progestins as the first-line medical therapies. Compared with second-line options, such as GnRH agonists/antagonists or AIs, the abovementioned first-line options are well tolerated, efficacious, and exhibit lower overall price. Future research priorities should be to identify novel target therapies and to evaluate the effects of available drugs through different routes of administration.

Next step in the development of mesoprogestins: the preclinical profile of EC313

Introduction

The pharmacological target for progesterone, different progestins, and Selective Progesterone Receptor Modulators (SPRMs) is the nuclear progesterone receptor (PR). EC313 is a new member of a subgroup of SPRMs, mesoprogestins, which combine especially PR- agonistic and PR-antagonistic activities in one molecule.

Methods

The suitable in vivo-model for the differentiation of SPRMs from the subgroup of mesoprogestins is the estrogen-primed juvenile rabbit endometrium assay (McPhail Assay). Remarkably, in contrast to other well-known SPRMs with no agonistic effects in this test, EC313 shows clear partial PR-agonistic effects that are higher than that of the well-known mesoprogestin Asoprisnil which already demonstrated remarkable clinical effectiveness for the treatment of uterine fibroids and endometriosis. The findings from the guinea pig studies presented here can be the impetus for further preclinical development of EC313. This model shows the same features for the termination of pregnancy by antiprogestins such as Mifepristone and Ulipristal acetate (UPA) in humans. Moreover, it is possible to distinguish between progestational and anti-progestational activities in the same experiment.

Results

The EC313 treatment reveals PR dominance in the genital tract and inhibits unopposed estrogenic effects. In very high doses (30.0 mg/animal/day subcutaneously (s.c.)) given twice on pregnancy days 43 and 44, no premature labor was induced (in contrast to UPA, dosed at 10.0 and 30. mg/animal/day s.c.). The anti-ovulatory activity of EC313 exceeds that of Ulipristal acetate or Mifepristone. EC313 binds to the steroid receptors in vitro with a similar affinity as the natural ligand progesterone. At the glucocorticoid receptor (GR) EC313 acts as a weak inhibitor. Minor activities at the human androgen receptor (AR) and mineralocorticoid receptor (MR) are considered negligible. No binding to the estradiol receptor was detected. In contrast to some in vitro-receptor findings, estrogenic, anti-estrogenic, androgenic, anti-androgenic, glucocorticoid, and anti-glucocorticoid actions were absent in vivo. The tissue selectivity of EC313 was demonstrated previously by reducing the growth and proliferation of uterine fibroids in animal models (lowest effective dosage 0.1 mg/kg/day s.c.).. As shown in this article, the anti-fibroid activity of EC313 was confirmed with a 10 times lower dosage (0.01 mg/kg/day s.c.). It was also shown that EC313 reduces the growth of endometriotic lesions in a human xenograft immune-deficient (NOD-SCID) mice model with a comparatively very low dosage range. In the aforementioned EC313 activity model, UPA was tested as the reference compound, the clinical effectiveness of which has already been demonstrated.

Discussion

For an explanation of these findings, the possibility is discussed that the mixed agonistic/antagonistic feature of EC313 is tissue target-specific based on its super-additive synergism characteristic for active bifunctional agents. In conclusion, the specific pharmacodynamic profile of this compound opens the possibility for the development of a drug with a distinct pharmaco-endocrinological profile against uterine fibroids, endometriosis, and other PR-dependent gynecological diseases.

Therapeutic options for the management of abnormal uterine bleeding

Just as the investigation of abnormal uterine bleeding (AUB) is approached systematically using the two FIGO systems for AUB in the reproductive years, treatment options can be considered similarly. Therapeutic options fall into two categories-medical and surgical-and while medical management is typically regarded as first-line therapy, there are several exceptions defined by the presenting cause or causes, mainly when infertility is a concurrent issue. In the early 1990s, up to 60% of women underwent a hysterectomy for the symptom of heavy menstrual bleeding (HMB), but this figure has decreased. The number of women undergoing a hysterectomy for benign disorders continues to decline, along with an increase in hysterectomies performed using minimally invasive techniques. Discussions about therapeutic options are tailored to the individual patient, and we include the risks and benefits of each option, including no management, to enable the patient to make an informed choice. The different types of treatment options and the factors affecting decision-making are considered in this article.

The use of a short course of Ulipristal Acetate for acute abnormal uterine bleeding in women without uterine fibroids

BACKGROUND

Ulipristal Acetate (UPA) is a synthetic selective progesterone receptor modulator. It is used as emergency contraception and to reduce pain and blood loss in women of reproductive age with uterine fibroids. The first mechanism of action is myometrial apoptosis, the second is on the hypo-thalamic-pituitary-ovarian axis and the third action, is an anti-proliferative effect on the endometrium. Mainly based on the latter two, UPA is increasingly used off-label in women with abnormal uterine bleeding (AUB) without fibroids.

OBJECTIVES

The aim of this paper is to find evidence for a short course of UPA to treat acute AUB without fibroids, performing a systematic review as well as scrutinising literature data on the pharmacokinetics and on short term bleeding control in women with fibroids.

MATERIALS AND METHODS

A systematic electronic literature review was performed in February 2022. Inclusion criteria were UPA administered to women without myomas in a setting of acute uterine bleeding. Further criteria included papers describing early bleeding control using UPA, deemed independent of the presence of fibroids, with specific attention to the median time to amenorrhoea.

MAIN OUTCOME MEASURES

The main outcome measured was the bleeding control within 10 days.

RESULTS

One case report was identified. The data on symptomatic women with fibroids using 5 mg or 10 mg daily revealed bleeding control was reported within 10 days in 81% and 89% respectively, with amenorrhoea in 57% and in 78% respectively.

CONCLUSION

A short-term administration may prove effective in abnormal uterine bleeding irrespective of the presence of uterine fibroids. However, more randomised controlled trials are needed and should be performed before implementation in general clinical practice.

WHAT IS NEW?

A short course of Ulipristal acetate as promising treatment for acute uterine bleeding without fibroids.

Progesterone Signaling and Uterine Fibroid Pathogenesis; Molecular Mechanisms and Potential Therapeutics

Uterine fibroids (UFs) are the most important benign neoplastic threat to women's health worldwide, with a prevalence of up to 80% in premenopausal women, and can cause heavy menstrual bleeding, pain, and infertility. Progesterone signaling plays a crucial role in the development and growth of UFs. Progesterone promotes the proliferation of UF cells by activating several signaling pathways genetically and epigenetically. In this review article, we reviewed the literature covering progesterone signaling in UF pathogenesis and further discussed the therapeutic potential of compounds that modulate progesterone signaling against UFs, including selective progesterone receptor modulator (SPRM) drugs and natural compounds. Further studies are needed to confirm the safety of SPRMs as well as their exact molecular mechanisms. The consumption of natural compounds as a potential anti-UFs treatment seems promising, since these compounds can be used on a long-term basis-especially for women pursuing concurrent pregnancy, unlike SPRMs. However, further clinical trials are needed to confirm their effectiveness.

The latest advances in the pharmacological management of endometriosis

INTRODUCTION

Endometriosis is a benign disease, characterized by a wide range of symptoms and different degrees of severity, which is why therapy should be individually adapted to the patient's needs. Over the years, a lot of research has gone into finding new therapeutic approaches for this enigmatic disease.

AREAS COVERED

This review presents the latest advances in pharmacological management of endometriosis and is solely focused on studies published from 2010 to 2021.

EXPERT OPINION

Clinicians and researchers are constantly searching for new therapeutic strategies for endometriosis patients. As there are well-established treatments, however, any new medication should fulfill at least one of the three criteria: increased efficacy, comparable efficacy but a better safety profile, or treatments that have a lack of accompanying contraceptive effects that are seen in most endometriosis treatments. While some new substances show promising results, further studies are needed to demonstrate the fulfillment of one of the above-mentioned criteria.

The effects of mifepristone on the structure of human decidua and chorion and Bax and Bcl-2 expression at early stage of pregnancy

Background

As a progesterone receptor antagonist, mifepristone combined with misoprostol is widely used to terminate early pregnancy in clinical practice. It has also been reported that mifepristone may cause cell death in decidual cells and result in hemorrhage of the decidua and insufficient blood supply. However, little is known about the histological effects of mifepristone on human decidua and chorion.

Methods

Histological and subcellular structural changes of decidua and chorionic villi from women taking mifepristone at early pregnancy times were examined by Hematoxylin and eosin (H&E) staining and transmission Electron microscope. The expression of apoptosis-related proteins Bax/Bcl-2 was examined by immunohistochemistry.

Results

After 48 h of mifepristone administration, the decidua tissue and chorionic villus structures were altered in women within 39–49 days of gestation and displayed varying degrees of degeneration and necrosis-like features. Apoptotic events were observed in the decidua and chorionic villi of early pregnancy, and mifepristone treatment significantly increases the number of apoptotic cells. The increased apoptotic events were concomitant with the increased expression of Bax and decreased expression of Bcl-2.

Conclusion

This study provides evidence that mifepristone induces histological and subcellular changes in decidua and chorionic villi. Mifepristone modulates the relative ratio of Bax/Bcl-2 and the increased apoptosis contributes to the pregnancy termination at early stage of pregnancy.

Spatial definition of the human progesterone receptor-B transcriptional complex

We report the quaternary structure of core transcriptional complex for the full-length human progesterone receptor-B (PR-B) homodimer with primary coactivator steroid receptor coactivator-2 (SRC-2) and the secondary coactivator p300/CREB-binding protein (CBP). The PR-B homodimer engages one SRC-2 mainly through its activation function 1 (AF1) in N-terminus. SRC-2 is positioned between PR-B and p300 leaving space for direct interaction between PR-B and p300 through PR-B's C-terminal AF2 and its unique AF3. Direct AF3/p300 interaction provides long-desired structural insights into the known functional differences between PR-B and the PR-A isoform lacking AF3. We reveal the contributions of each AF and demonstrate their structural basis in forming the PR-B dimer interface and PR-B/coactivator complex. Comparison of the PR-B/coactivator complex with other steroid receptor (estrogen receptor and androgen receptor) complexes also shows that each receptor has its unique mechanism for recruiting coactivators due to the highly variable N-termini among receptors.

Uterine bleeding: how understanding endometrial physiology underpins menstrual health

Menstruation is a physiological process that is typically uncomplicated. However, up to one third of women globally will be affected by abnormal uterine bleeding (AUB) at some point in their reproductive years. Menstruation (that is, endometrial shedding) is a fine balance between proliferation, decidualization, inflammation, hypoxia, apoptosis, haemostasis, vasoconstriction and, finally, repair and regeneration. An imbalance in any one of these processes can lead to the abnormal endometrial phenotype of AUB. Poor menstrual health has a negative impact on a person's physical, mental, social, emotional and financial well-being. On a global scale, iron deficiency and iron deficiency anaemia are closely linked with AUB, and are often under-reported and under-recognized. The International Federation of Gynecology and Obstetrics have produced standardized terminology and a classification system for the causes of AUB. This standardization will facilitate future research endeavours, diagnosis and clinical management. In a field where no new medications have been developed for over 20 years, emerging technologies are paving the way for a deeper understanding of the biology of the endometrium in health and disease, as well as opening up novel diagnostic and management avenues.

Premenstrual Syndrome and Premenstrual Dysphoric Disorder as Centrally Based Disorders

Premenstrual syndrome (PMS) and premenstrual dysphoric disorder (PMDD) encompass a variety of symptoms that occur during the luteal phase of the menstrual cycle and impair daily life activities and relationships. Depending on the type and severity of physical, emotional or behavioral symptoms, women of reproductive age followed for at least two prospective menstrual cycles may receive one of the two diagnoses. PMDD is the most severe form of PMS, predominantly characterized by emotional and behavioral symptoms not due to another psychiatric disorder. PMS and PMDD are common neuro-hormonal gynecological disorders with a multifaceted etiology. Gonadal steroid hormones and their metabolites influence a plethora of biological systems involved in the occurrence of specific symptoms, but there is no doubt that PMS/PMDD are centrally based disorders. A more sensitive neuroendocrine threshold to cyclical variations of estrogens and progesterone under physiological and hormonal therapies is present. Moreover, altered brain sensitivity to allopregnanolone, a metabolite of progesterone produced after ovulation potentiating GABA activity, along with an impairment of opioid and serotoninergic systems, may justify the occurrence of emotional and behavioral symptoms. Even neuro-inflammation expressed via the GABAergic system is under investigation as an etiological factor of PMS/PMDD. Pharmacological management aims to stabilize hormonal fluctuations and to restore the neuroendocrine balance. The rationale of suppressing ovulation supports prescription of combined hormonal contraception (CHC). Its effect on mood is highly variable and depends on biochemical characteristics of exogenous steroids and on type and severity of symptoms. Hormonal regimens reducing the estrogen-free interval or suppressing menstruation seem better choices. Psychoactive agents, such as serotonin reuptake inhibitors (SSRIs), are effective in reducing the symptoms of PMS/PMDD and may be prescribed continuously or only during the luteal phase. Novel therapeutic approaches include inhibition of progesterone receptors in the brain, i.e., with ulipristal acetate, reduced conversion of progesterone with dutasteride, and modulation of the action of allopregnanolone on the brain GABAergic system with sepranolone.