Nestorone: a progestin with a unique pharmacological profile

Progesterone Receptor Agonist, Nestorone, Exerts Long-Term Neuroprotective Effects Against Permanent Focal Cerebral Ischemia in Adult and Aged Male Rats

Stroke is a leading cause of death and disability worldwide. Tissue plasminogen activator (tPA) is currently the most effective medicine for stroke; however, it has a narrow therapeutic time window (4.5 h after symptom onset). We demonstrated that nestorone, a progesterone (P4) receptor agonist, exerted neuroprotective effects against transient focal cerebral ischemia 6 h post-ischemic administration in adult male rats. This study examines its effects on permanent focal cerebral ischemia in adult and aged male rats, which are better models for evaluating treatment outcomes in typical stroke patients. Adult (6-month-old) or aged (18-month-old) male rats subjected to permanent middle cerebral artery occlusion (pMCAO) were continuously administered nestorone (10µg/day) or its vehicle (30% hydroxypropyl-β-cyclodextrin) for 7 days via an osmotic pump subcutaneously implanted, starting at 18 h post-pMCAO. Nestorone-treated adult male rats showed marked improvements in behavioral outcomes in the adhesive removal and rotarod tests and a significant reduction in infarct size compared to vehicle-treated rats 9 and 30 days post-pMCAO. The same administration of nestorone resulted in apparently comparable neuroprotective effects in aged male rats. The inflammatory mediator NF-κB/p65 was increased in Iba-1 positive cells 24 h post-pMCAO, but was significantly suppressed by subcutaneous injection of nestorone. These results suggested that nestorone exerts long-term neuroprotective effects against permanent focal cerebral ischemia in adult and aged male rats. Nestorone is thus a promising agent for post-stroke treatment owing to its wide age-independent therapeutic time window (18 h after symptom onset), which is longer than that of tPA therapy.

Therapeutic potential of enzymes, neurosteroids, and synthetic steroids in neurodegenerative disorders: A critical review

Neurodegenerative disorders present a significant challenge to healthcare systems, mainly due to the limited availability of effective treatment options to halt or reverse disease progression. Endogenous steroids synthesized in the central nervous system, such as pregnenolone (PREG), dehydroepiandrosterone (DHEA), progesterone (PROG), and allopregnanolone (ALLO), have been identified as potential therapeutic agents for neurodegenerative diseases. Neurosteroids such as ALLO, DHEA, and PROG, as well as their synthetic analogs like Ganaxolene, Fluasterone, and Olexoxime, offer promising effects for conditions such as Alzheimer's disease (AD) and depression. Moreover, Brexanolone and Ganaxolone are synthetic steroids approved for the treatment of postpartum depression and epilepsy, respectively. Neurosteroids such as ALLO are crucial in modulating GABAergic neurotransmission and reducing neuroinflammation. These compounds enhance the activity of GABA-A receptors, leading to increased inhibitory signaling in the brain, which can help regulate mood, cognition, and neuroprotection. Small clinical trials and observational studies indicate that ALLO may have cognitive benefits, but no large-scale, definitive meta-analysis confirms a 20 % improvement in AD patients. Mitochondrial dysfunction plays a vital role in the pathogenesis of numerous neurological diseases due to the high-energy demand and sensitivity of neurons to oxidative stress. Reduced mitochondrial function leads to amyloid-beta plaques and tau tangles accumulation in AD. In Parkinson's disease (PD), mitochondrial dysfunction resulting from the PINK1 or Parkin genes leads to energy deficiencies and the accumulation of toxic byproducts. Mutations in genes such as SOD1, C9orf72, and TDP-43 have been associated with mitochondrial dysfunction in amyotrophic lateral sclerosis (ALS). Moreover, studies on these neurodegenerative diseases suggest that inflammation is not merely a consequence of neurodegeneration but is also an essential factor in this process. Many neurological disorders involve multifaceted interactions between genetics, the environment, and immune responses, making it difficult to pinpoint their exact causes. Future research aims to overcome these hurdles through genetic advances, regenerative medicine, and personalized therapies. Cutting-edge technologies such as artificial intelligence and high-throughput screening are expected to accelerate drug discovery and improve diagnostic accuracy. Increasing collaboration between interdisciplinary fields such as bioinformatics, neuroscience, and immunology will lead to innovative treatment strategies. This comprehensive review discusses the therapeutic effects of enzymes, neurosteroids, and synthetic steroids in different neurodegenerative diseases, particularly AD, PD, ALS, and MS. Potential challenges in the therapeutic use of neurosteroids, such as the limited bioavailability and off-target effects of synthetic steroids, are also discussed, and an up-to-date and comprehensive review of the impact of these steroids on neurodegenerative disorders is presented.

Effects of nestorone, a progesterone receptor agonist, on neonatal hypoxic-ischemic brain injury and reproductive functions in male and female rats

Perinatal hypoxic-ischemic encephalopathy (HIE) is one of the leading causes of neonatal death and neurological disorders. We recently demonstrated the neuroprotective effects of nestorone, a progesterone receptor agonist, in adult male rats subjected to focal cerebral ischemia; however, its effects on neonatal ischemic brain injury and on sexual differentiation and reproductive functions remain unclear. Therefore, the present study investigated the effects of nestorone on neonatal hypoxic-ischemic brain injury and reproductive functions in rats of both sexes. Seven-day-old male and female rat pups were subjected to occlusion of the right carotid artery and then exposed to 8 % oxygen (hypoxic-ischemia, HI). Brain lesion sizes and the numbers of activated astrocytes and microglia in male and female rats were significantly lower after administrating 10 μg/kg nestorone than vehicle 48 h after HI. Furthermore, the post-HI administration of nestorone for 7 days (10 μg/kg, once a day) significantly improved motor coordination and tactile responses 28 days after HI and cognitive performance 4 months after HI in male and female rats. The administration of nestorone did not affect the delivery rates or number of weaned pups in HI and sham-operated female rats or in intact female rats mated with HI or sham-operated males. These results suggest that nestorone exerts persistent neuroprotective effects against neonatal HI brain injury without serious adverse effects on reproductive functions in male and female rats. Therefore, nestorone is a promising potent and safe therapeutic agent in newborn infants with HIE of both sexes.

Development of a transdermal gel for reversible male contraception

While there are several easy-to-use reversible female contraceptives, little is available for men. Introduction of novel, cost-effective male contraceptives could have important downstream global health and economic benefits. Currently, nearly half of all pregnancies globally are unintended, with many resulting in unsafe abortions, a significant burden for women and families in many countries. Available reversible options for male contraception include male condoms or withdrawal, both with high typical use failure rates, and vasectomy, which is not easily reversible. Advanced methods of male hormonal contraception include combinations of progestin and androgen, generally testosterone itself. Administration of these steroids results in the suppression of gonadotropins leading to the suppression of sperm production with full reversibility within a few months. Importantly, the exogenous androgen replaces the suppressed endogenous testosterone, minimizing side effects for the user. Using the skin to deliver steroids in the systemic circulation is a well-accepted concept both for the treatment of hypogonadism and contraception. A transdermal gel delivering Nestorone (segesterone acetate) and testosterone is under development and is leading the way in advancing novel, self-delivered methods of male hormonal contraception.

Cellular and molecular mechanisms of action of ovarian steroid hormones. I: Regulation of central nervous system function

The conventional way steroid hormones work through receptors inside cells is widely acknowledged. There are unanswered questions about what happens to the hormone in the end and why there isn't always a strong connection between how much tissue takes up and its biological effects through receptor binding. Steroid hormones can also have non-traditional effects that happen quickly but don't involve entering the cell. Several possible mechanisms for these non-traditional actions include (a) changes in membrane fluidity, (b) steroid hormones acting on receptors on the outer surface of cells, (c) steroid hormones regulating GABAA receptors on cell membranes, and (d) activation of steroid receptors by factors like EGF, IGF-1, and dopamine. Data also suggests that steroid hormones may be inserted into DNA through receptors, acting as transcription factors. These proposed new mechanisms of action should not be seen as challenging the conventional mechanism. Instead, they contribute to a more comprehensive understanding of how hormones work, allowing for rapid, short-term, and prolonged effects to meet the body's physiological needs.

Metabolism of progestogens used for contraception and menopausal hormone therapy

A variety of progestogens are widely used by women for contraception and menopausal hormone therapy. The progestogens undergo extensive metabolism by oral and parenteral routes of administration to form many metabolites. Although a small number of metabolites have been shown to be biologically active, most have not been tested for biologic activity. The present review shows that we know most about progesterone metabolism, followed by the metabolism of levonorgestrel and norethindrone. Very few studies have been carried out on metabolism of most of the progestogens. The clinical significance of this deficiency is that those progestogen metabolites that bind to the progesterone receptors may also bind to other steroid receptors and be responsible for some of the well-documented side effects of administered progestogens. We also discuss how obesity and genetic polymorphisms alter progestogen metabolism, and how development of oral progestogen formulations that are targeted to the colon, where the concentration of steroid-metabolizing enzymes is much lower than in the proximal gut, may have a beneficial effect on progestogen metabolism.

Nestorone (segesterone acetate) effects on neuroregeneration

Nestorone® (segesterone acetate) is a progestin with a chemical structure closely related to progesterone with high affinity and selectivity for the progesterone receptor without significant interaction with other steroid receptors. It has been developed for female and male contraception and is FDA-approved in a first long-acting contraceptive vaginal system for female contraception. Its safety has been extensively demonstrated in both preclinical and clinical studies for contraceptive indications. Nestorone was found to display neuroprotective and neuroregenerative activity in animal models of various central nervous system diseases, including multiple sclerosis, stroke, and amyotrophic lateral sclerosis. Reviewed herein are neuroprotective and myelin- regenerating properties of Nestorone in various animal models and its translational potential as a therapeutic agent for debilitating neurological diseases for which limited therapeutic options are available (Table 1).

The effect of hormonal contraceptive therapy on clinical laboratory parameters: a literature review

Hormonal contraceptives (HC) are widely used among women in reproductive ages. In this review, the effects of HCs on 91 routine chemistry tests, metabolic tests, and tests for liver function, hemostatic system, renal function, hormones, vitamins and minerals were evaluated. Test parameters were differently affected by the dosage, duration, composition of HCs and route of administration. Most studies concerned the effects of combined oral contraceptives (COC) on the metabolic, hemostatic and (sex) steroids test results. Although the majority of the effects were minor, a major increase was seen in angiotensinogen levels (90-375 %) and the concentrations of the binding proteins (SHBG [∼200 %], CBG [∼100 %], TBG [∼90 %], VDBP [∼30 %], and IGFBPs [∼40 %]). Also, there were significant changes in levels of their bound molecules (testosterone, T3, T4, cortisol, vitamin D, IGF1 and GH). Data about the effects of all kinds of HCs on all test results are limited and sometimes inconclusive due to the large variety in HC, administration routes and dosages. Still, it can be concluded that HC use in women mainly stimulates the liver production of binding proteins. All biochemical test results of women using HC should be assessed carefully and unexpected test results should be further evaluated for both methodological and pre-analytical reasons. As HCs change over time, future studies are needed to learn more about the effects of other types, routes and combinations of HCs on clinical chemistry tests.

Breast cancer risk association with postmenopausal hormone therapy: Health Insurance Database in South Korea-based cohort study

CONTEXT

Although many physicians have been concerned that the menopausal hormones used currently in clinical practice may affect the risk of breast cancer, there are currently few informative updated studies about the associations between menopausal hormone therapy (MHT) and the risk of breast cancer.

OBJECTIVE

This study aims to evaluate the association between the risk of breast cancer and MHT using the National Health Insurance Database in South Korea (HISK) cohort between 2002 and 2019 retrospectively.

METHODS

Postmenopausal women over 40 years of age from 2003 to 2011 were selected as the subject population, and their follow-up data were collected until 2019. We analyzed the risk and mortality of breast cancer according to the type of MHT received, namely, tibolone, combined estrogen plus progestin by manufacturer (CEPM), oral estrogen, combined estrogen plus progestin by physician (CEPP), or topical estrogen.

RESULTS

The risk of breast cancer increased in the CEPM group [hazard ratio (HR) 1.439, 95% CI 1.374-1.507, P-value < .001] in comparison with the non-MHT group. However, no significant associations were found between the use of tibolone, oral estrogen, CEPP, or topical estrogen and breast cancer risk in comparison with the non-MHT group (HR 0.968, 95% CI 0.925-1.012; HR 1.002, 95% CI 0.929-1.081; HR 0.929, 95% CI 0.75-1.15; HR 1.139, 95% CI 0.809-1.603). The mortality rate from breast cancer is lower in the MHT group in comparison with the non-MHT group, indicating that significant associations were found for tibolone, CEPM, and oral estrogen (HR 0.504, 95% CI 0.432-0.588; HR 0.429, 95% CI 0.352-0.522; HR 0.453 95% CI 0.349-0.588, P-value < .001).

CONCLUSIONS

This study suggests that the risk of breast cancer is increased by drugs in the CEPM group but not by tibolone, oral estrogen, CEPP, or topical estrogen. The mortality rate from breast cancer is lower with MHT (tibolone, CEPM, oral estrogen) than without MHT.

Male contraception: narrative review of ongoing research

BACKGROUND

Since the release of the combined oral contraceptive pill in 1960, women have shouldered the burden of contraception and family planning. Over 60 years later, this is still the case as the only practical, effective contraceptive options available to men are condoms and vasectomy. However, there are now a variety of promising hormonal and non-hormonal male contraceptive options being studied. The purpose of this narrative review is to provide clinicians and laypeople with focused, up-to-date descriptions of novel strategies and targets for male contraception. We include a cautiously optimistic discussion of benefits and potential drawbacks, highlighting several methods in preclinical and clinical stages of development.

RESULTS

As of June 2023, two hormonal male contraceptive methods are undergoing phase II clinical trials for safety and efficacy. A large-scale, international phase IIb trial investigating efficacy of transdermal segesterone acetate (Nestorone) plus testosterone gel has enrolled over 460 couples with completion estimated for late 2024. A second hormonal method, dimethandrolone undecanoate, is in two clinical trials focusing on safety, pharmacodynamics, suppression of spermatogenesis and hormones; the first of these two is estimated for completion in December 2024. There are also several non-hormonal methods with strong potential in preclinical stages of development.

CONCLUSIONS

There exist several hurdles to novel male contraception. Therapeutic development takes decades of time, meticulous work, and financial investment, but with so many strong candidates it is our hope that there will soon be several safe, effective, and reversible contraceptive options available to male patients.

Exposure to endogenous and exogenous sex hormones and reproductive history influence prognosis in women with ALS

INTRODUCTION/AIMS

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with a higher incidence in men suggesting an influence of sex steroids. Our objective was to investigate past exposure to endogenous and synthetic steroids in female ALS patients and controls.

METHODS

We administered a questionnaire to 158 postmenopausal women (75 ALS patients and 83 controls). We calculated reproductive time span (RTS), lifetime endogenous estrogen (LEE) and progesterone exposures (LPE), oral contraceptive pill (OCP) use, and reproductive history.

RESULTS

ALS patients showed shorter LEE and LPE, a lower proportion of breast cancer, and 11% showed no history of pregnancies vs. 4% of controls. Odds ratios (ORs) showed that <17 y of LEE and a delayed menarche (>13 y) constitute risk factors for ALS [OR = 2.1 (95% confidence interval {CI}, 1.08-4.2); and OR = 2.4 (95% CI, 1.1-5.1) respectively]. According to Cox survival analysis, for each year the LEE increased over 17 y, it was independently associated with longer survival [hazard ratio (HR) = 0.37 (95% CI, 0.16-0.85)] after adjusting for smoking, age and site of onset. Multivariate regression analysis demonstrated that for each month using OCP for longer than 40 mo increased the risk of ALS [adjusted OR = 4.1 (95% CI, 1.2-13.8)].

DISCUSSION

Thus, longer exposure to endogenous female sex steroids increased survival and reduced ALS susceptibility. In contrast, longer exposure to synthetic sex steroids showed a negative impact by reducing the production of endogenous female sex steroids or due to crossover with other steroid receptors. Given the neuroprotective effects of sex steroids, we suggest that abnormalities of neuroendocrine components may alter motor function in women with ALS.

Clinical Approaches to Nestorone Subdermal Implant Therapy in Women's Health

Segesterone acetate (SA) or Nestorone, a fourth-generation progestogen, is a synthetic compound with high progestational activity and no androgenic, glucocorticoid, or anabolic effects. However, due to its oral inactivity, SA must be used by other routes, such as subcutaneous. Thus, considering its peculiar properties, the SA subdermal implant is successfully used in female contraception and postmenopausal hormone replacement therapy (HRT). In recent years, its potential uses in endometriosis, polycystic ovaries syndrome (PCOS), and a new therapeutic possibility for neuroprotection have made this treatment extremely interesting. However, the absence of a standardized dose and the long-term safety of SA implant therapy in women is still controversial. Here, we present the possible indications, doses, limitations, and side effects of SA implant therapy.

Satisfaction with a Segesterone Acetate and Ethinyl Estradiol Contraceptive Vaginal System Among Recent Oral Contraceptive or Hormonal Contraceptive Vaginal Ring Users

Background: We evaluated satisfaction with use of a segesterone acetate and ethinyl estradiol (0.15/0.013 mg) contraceptive vaginal system (CVS) among women who had recently used a monthly contraceptive vaginal ring or contraceptive pills. The CVS is a ring-shaped device used in a 21-days-in/7-days-out regimen for 13 cycles. Materials and Methods: We analyzed post hoc satisfaction responses at cycle 3 and end of study (EOS) from a subset of participants with documented recent use of the monthly ring or daily pills before enrollment in a multinational, phase 3, 13-cycle trial evaluating the CVS. EOS included results from participants who had completed ≥10 cycles. Results were summarized descriptively. Results: We identified 128 recent ring and 219 recent pill users at cycle 3 (of 1033 survey participants), and 92 and 148, respectively, at EOS (of 622 survey participants); overall satisfaction with CVS use was high (≥90%). At EOS, most ring (89%) and pill (97%) users liked the CVS as much/better than any previous method. The two most-liked CVS features included ease of use and 1-year duration; the two most disliked features included ring insertion and feeling it coming out. At EOS, ≥88% of both groups reported no concern about using the same CVS for a year, and most (>80%) had recommended it to friends or family members. Conclusion: The CVS clinical trial participants who were recent ring/pill users reported high satisfaction and liked it as much/better than any previously used contraceptive; the CVS may be a good contraceptive option for switchers. Clinical trial registration NCT00263341.

Evaluations of memory, anxiety, and the growth factor IGF-1R after post-surgical menopause treatment with a highly selective progestin

Progestogens are a key component of menopausal hormone therapies. While some progestogens can be detrimental to cognition, there is preclinical evidence that progestogens with a strong progesterone-receptor affinity benefit some molecular mechanisms believed to underlie cognitive function. Thus, a progestin that maximizes progesterone-receptor affinity and minimizes affinities to other receptors may be cognitively beneficial. We evaluated segesterone-acetate (SGA), a 19-norprogesterone derivative with a strong progesterone-receptor affinity and no androgenic or estrogenic-receptor activity, hypothesizing that it would enhance cognition. Middle-aged rats underwent Sham or Ovariectomy (Ovx) surgery followed by administration of medroxyprogesterone-acetate (MPA; used as a positive control as we have previously shown MPA-induced cognitive deficits), SGA (low or high dose), or vehicle (one Sham and one Ovx group). Spatial working and reference memory, delayed retention, and anxiety-like behavior were assessed, as were memory- and hormone- related protein assays within the frontal cortex, dorsal hippocampus, and entorhinal cortex. Low-dose SGA impaired spatial working memory, while high-dose SGA had a more extensive detrimental impact, negatively affecting spatial reference memory and delayed retention. Replicating previous findings, MPA impaired spatial reference memory and delayed retention. SGA, but not MPA, alleviated Ovx-induced anxiety-like behaviors. On two working memory measures, IGF-1R expression correlated with better working memory only in rats without hormone manipulation; any hormone manipulation or combination of hormone manipulations used herein altered this relationship. These findings suggest that SGA impairs spatial cognition after surgical menopause, and that surgical menopause with or without progestin administration disrupts relationships between a growth factor critical to neuroplasticity.

Microneedle-assisted transdermal delivery of nanoparticles: Recent insights and prospects

Transdermal delivery of drugs offers an interesting alternative for the administration of molecules that present certain troubles when delivered by the oral route. It can produce systemic effects or perform a local action when the formulation exerts an optimal controlled drug release or a targeted delivery to the specific cell type or site. It also avoids several inconveniences of the oral administration such as the hepatic first pass effect, gastric pH-induced hydrolysis, drug malabsorption because of certain diseases or surgeries, and unpleasant organoleptic properties. Nanomedicine and microneedle array patches (MAPs) are two of the trendiest delivery systems applied to transdermal research nowadays. However, the skin is a protective barrier and nanoparticles (NPs) cannot pass through the intact stratum corneum. The association of NPs and MAPs (NPs@MAPs) work synergistically, since MAPs assist NPs to bypass the outer skin layers, and NPs contribute to the system providing controlled drug release and targeted delivery. Vaccination and tailored therapies have been proposed as fields where both NPs and MAPs have great potential due to inherent characteristics. MAPs conception and easy use could allow self-administration and therefore facilitate mass vaccination campaigns in undeveloped areas with weak healthcare services. Additionally, nanomedicine is being explored as a platform to personalize therapies in such an important field as oncology. In this work we show recent insights that prove the benefits of NPs@MAPs association and analyze the prospects and the discrete interest of the industry in NPs@MAPs, evaluating different limiting steps that restricts NPs@MAPs translation to the clinical practice. This article is categorized under: Nanotechnology Approaches to Biology > NA Therapeutic Approaches and Drug Discovery > NA.

Combined effects of the contraceptive hormones, ethinyl estradiol and levonorgestrel, on the use of place and response memory in gonadally-intact female rats

During maze navigation rats can rely on hippocampus-mediated place memory or striatum-mediated response memory. Ovarian hormones bias whether females use place or response memory to reach a reward. Here, we investigated the impact of the contraceptive hormones, ethinyl estradiol (EE) and levonorgestrel (LNG), on memory bias. A total of 63 gonadally-intact female rats were treated with either 10 μg/kg of EE alone, 20 μg/kg of LNG alone, both 10 μg/kg of EE and 20 μg/kg of LNG together, or a sesame oil injection with 5% ethanol as a vehicle control. Rats in the control condition were tested during the diestrus phase of the estrous cycle in order to control for the low circulating levels of gonadotropin and ovarian hormones that occur with oral contraceptive administration. Rats treated with LNG alone had a bias towards the use of place memory compared to diestrus phase control rats. This bias was not observed if LNG was administered in combination with EE. Rats treated with EE or EE+LNG did not have a statistically significant difference in memory bias compared to rats in the control group. These data show that synthetic hormones contained in oral contraceptives administered to females influence which cognitive strategy is predominantly used during navigation.

What is there to know about the effects of progestins on the human brain and cognition?

Progestins are an important component of hormonal contraceptives (HCs) and hormone replacement therapies (HRTs). Despite an increasing number of studies elucidating the effects of HCs and HRTs, little is known about the effects of different types of progestins included in these medications on the brain. Animal studies suggest that various progestins interact differently with sex steroid, mineralocorticoid and glucocorticoid receptors and have specific modulatory effects on neurotransmitter systems and on the expression of neuropeptides, suggesting differential impacts on cognition and behavior. This review focuses on the currently available knowledge from human behavioral and neuroimaging studies pooled with evidence from animal research regarding the effects of progestins on the brain. The reviewed information is highly relevant for improving women's mental health and making informed choices regarding specific types of contraception or treatment.

Modeling hormonal contraception in female rats: A framework for studies in behavioral neurobiology

Research on hormonal contraceptives (HC) in animal models is lacking, and as a result, so is our understanding of the impact of HC on the brain and behavior. Here, we provide a review of the pharmacology of HC, as well as the methodology and best practices for designing a model of HC in female rats. We outline specific methodological considerations regarding dosing, route of administration, exposure time/timing, and selecting a control group. We also provide a framework outlining important levels of analysis for thinking about the impact of HC on behavioral and neurobiological outcomes. The purpose of this review is to equip researchers with foundational knowledge, and some basic elements of experimental design for future studies investigating the impact of HC on the brain and behavior of female rats.

Progesterone: A Steroid with Wide Range of Effects in Physiology as Well as Human Medicine

Progesterone is a steroid hormone traditionally linked with female fertility and pregnancy. In current reproductive medicine, progesterone and its analogues play crucial roles. While the discovery of its effects has a long history, over recent decades, various novel actions of this interesting steroid have been documented, of which its neuro- and immunoprotective activities are the most widely discussed. Discoveries of the novel biological activities of progesterone have also driven research and development in the field of progesterone analogues used in human medicine. Progestogen treatment has traditionally and predominately been used in maintaining pregnancy, the prevention of preterm labor, various gynecological pathologies, and in lowering the negative effects of menopause. However, there are also various other medical fields where progesterone and its analogues could find application in the future. The aim of this work is to show the mechanisms of action of progesterone and its metabolites, the physiological and pharmacological actions of progesterone and its synthetic analogues in human medicine, as well as the impacts of its production and use on the environment.

Differential off-target glucocorticoid activity of progestins used in endocrine therapy

The glucocorticoid receptor (GR) regulates transcription of genes involved in multiple processes. Medroxyprogesterone acetate (MPA), widely used in the injectable contraceptive Depo-MPA (DMPA), has off-target effects via the GR, which may result in side-effects in endocrine therapy. However, very little is known about the GR activity of other progestins used in endocrine therapy. This study compared GR activities for several progestins, using whole cell binding, dose-response, and GR phosphorylation assays, in both a cell line model and peripheral blood mononuclear cells (PBMCs). MPA, etonogestrel (ETG) and nestorone (NES) exhibit greater relative binding affinities for the GR than levonorgestrel (LNG) and norethisterone/norethindrone (NET) and are partial GR agonists for transactivation but agonists for transrepression on synthetic promoters in COS-1 cells. MPA is a potent agonist for endogenous GR-regulated GILZ and IL6 genes in PBMCs. While ETG and NES also display agonist activity on IL6, they have little effect on GILZ. In contrast, LNG and NET exhibit little to no activity in transactivation models, while both exhibit some transrepressive activity but are generally less potent and/or efficacious than MPA. Antagonist and phosphorylation assays confirmed that MPA and NES act via the GR on endogenous genes in PBMCs. Our results suggest GR-mediated dose-dependent and gene-specific transcriptional side-effects are likely to occur at physiologically relevant concentrations in vivo for MPA, may possibly occur selectively for ETG and NES, but are unlikely to occur for LNG and NET. This suggests that these progestins will exhibit differential side-effects in endocrine therapy via the GR.

Contraceptive drug, Nestorone, enhances stem cell-mediated remodeling of the stroke brain by dampening inflammation and rescuing mitochondria

Ischemic stroke remains a significant unmet need causing massive mortality and morbidity due to few treatment options with limited therapeutic window. The progestin Nestorone® (segesterone acetate) displays high affinity for the progesterone receptor in exerting its potent birth control and hormone replacement therapy. Accumulating evidence implicates a new utility of Nestorone in affording neuroprotection in a variety of central nervous system diseases, including stroke. However, the mechanism of action mediating Nestorone's neuroprotection in stroke remains unknown. Here, we showed that stand-alone treatments of Nestorone or human amniotic fluid-derived stem cells (hAFSc), but more pronounced with their combined treatment, led to significant improvements in behavioral function and reductions in infarction and peri-infarct cell loss in adult rats with ischemic stroke. We detected significantly lower levels of pro-inflammatory signals (OX6 and IBA1) coupled with enhanced levels of stem cell proliferation (Ki67) and differentiation (DCX and MAP2) in both brain and spleen of stroke rats that received stand-alone or combined treatments of Nestorone and hAFSc. In concert, the in vitro oxygen-glucose deprivation stroke model revealed that neural stem cells treated with Nestorone exhibited increased stem cell proliferation and differentiation that was accompanied by rescue of the mitochondrial respiratory activity characterized by reduced mitochondrial reactive oxygen species, increased ATP, elevated mitochondrial deacetylase Sirtuin 3 (SIRT3), and a normalized ratio of acetyl-superoxide dismutase 2 (Ac-SOD2)/SOD2, suggesting the key role of mitochondrial metabolism and oxidative protection in Nestorone's therapeutic effects in stroke.

Nestorone nanosuspension-loaded dissolving microneedles array patch: A promising novel approach for "on-demand" hormonal female-controlled peritcoital contraception

"On demand" hormonal female-controlled pericoital contraception is one strategy which could be used to minimize the impact of unintended pregnancy. Nestorone (NES) is a potent contraceptive, with relatively few side effects in comparison with other contraceptives. NES presents an attractive option for "on demand" pericoital contraceptive. Unfortunately, the drug is inactive if taken orally, but it has high progestational activity and antiovulatory potency if administered parenterally. Current drug delivery systems, such as a transdermal hydrogel are not so satisfactory. Dissolving microneedles array (DMNs) are an attractive alternative, minimally-invasive, delivery system. In this study, we report, for the first time, development of tip-loaded NES-nanosuspension (NES-NS)-loaded bilayer DMNs to deliver NES intradermally for subsequent release. NES-NS was prepared and optimised, freeze-dried and then used to fabricate DMNs using a blend of two biocompatible polymers, namely poly(vinyl alcohol) and poly(vinyl pyrrolidone). Both NES-NS and the NES-NS-loaded DMNs were fully characterised and the performance of the DMNs was evaluated in vivo using Sprague Dawley rats. Results showed that the finalised NES-NS had particle size and PDI values of 666.06 ± 1.86 nm and 0.183 ± 0.01, respectively. The NES-NS-DMNs had relatively high tips-localised drug loading (approximately 2.26 ± 1.98 mg/array) and exhibited satisfactory mechanical and insertion properties. In Sprague Dawley rats, DMNs delivered NES into the skin, with the drug then appearing in blood and rapidly reaching its maximum concentration (C_max of 32.68 ± 14.06 ng/mL) within 1h post-DMNs application. Plasma levels above 3.4 ng/mL were maintained for 2 days. This suggests that DMNs are a promising drug delivery system that could be used to deliver NES as an "On demand" hormonal female-controlled pericoital contraceptive.

Sex differences in the cerebroprotection by Nestorone intranasal delivery following stroke in mice

Our previous studies showed that intranasal delivery of progesterone offers a good bioavailability and neuroprotective efficacy after experimental stroke. We have also demonstrated that progesterone receptors (PR) are essential for cerebroprotection by endogenous progesterone and by progesterone treatment. The identification of PR as a potential drug target for stroke therapy opens new therapeutic indications for selective synthetic progestins. Nestorone® (16-methylene-17α-acetoxy-19-nor-pregn-4-ene-3, 20-dione, also known as segesterone acetate) is a 19-norprogesterone derivative that more potently targets PR than progesterone. The objective of this study was to evaluate the cerebroprotective efficiency of intranasal administration of Nestorone after middle cerebral occlusion (MCAO) in mice. We show here that intranasal administration is a very efficient route to achieve a preferential delivery of Nestorone to the brain and confers a slow elimination and a sustained bioavailability. Furthermore, intranasal administration of Nestorone (at 0.08 mg/kg) improved the functional outcomes and decreased the ischemic lesion in male but not in female mice at 48 h post MCAO. Use of PR^NesCre mice, selectively lacking expression of PR in neural cells, and their control PR^loxP/loxP littermates showed that the cerebroprotective effects of Nestorone in male mice depended on neural PR as they were not observed in PR^NesCre mice. Our findings show that intranasal delivery of Nestorone may be an efficient strategy to promote recovery after stroke in males and confirm the key role of PR in cerebroprotection. Furthermore, they point to sex differences in the response to Nestorone treatment and emphasize the necessity to include males and females in experimental studies.

Contraceptive Technologies: Looking Ahead to New Approaches to Increase Options for Family Planning

With persistently high global rates of unintended pregnancy and contraceptive nonuse, nonadherence and discontinuation, new contraceptive methods must address the needs of women and men who seek alternatives to their current options. Methods under development aim to reduce potential side effects, improve access and ease of use, ensure safety, increase secondary benefits associated with method use and expand options for both women and men. Developmental approaches employed to enhance current methods utilize new delivery systems and novel active pharmaceutical ingredients. This will improve overall user satisfaction with the methods used while expanding the number of options available to provide choice and value user autonomy in the highly diverse contraceptive markets around the world.

Limbic progesterone receptor activity enhances neuronal excitability and seizures

OBJECTIVE

Emerging evidence raises the possibility that progesterone receptor (PR) signaling may contribute to the reproductive hormone fluctuation-linked seizure precipitation, called catamenial epilepsy. Therefore, we studied PR isoform expression in limbic regions involved in temporal lobe epilepsy and the effect of PR activation on neuronal activity and seizures.

METHODS

We evaluated PR expression in the limbic regions, entorhinal cortex (EC), hippocampus, and amygdala in female rats using quantitative real-time polymerase chain reaction (qRT-PCR). A selective agonist, Nestorone (16-methylene-17 alpha-acetoxy-19-nor-pregn-4-ene-3,20-dione) activated PRs, and the effect on excitability and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR)-mediated synaptic transmission of EC neurons was studied using electrophysiology. Finally, we assessed PR regulation of epileptic seizures and status epilepticus (SE) induced by lithium-pilocarpine in female rats with the global deletion of PRs (PR knockout; PRKO) using video electroencephalography (-EEG).

RESULTS

Limbic regions EC, hippocampus, and amygdala robustly expressed PR messenger RNA (mRNA). Nestorone (16-methylene-17 alpha-acetoxy-19-nor-pregn-4-ene-3,20-dione) treatment reduced the action potential threshold of layer II/III EC neurons and increased the frequency of AMPA receptor-mediated synaptic currents of ovariectomized and estrogen-primed female rats. Female rats lacking PRs (PRKO) experienced a shorter duration, less intense, and less fatal SE than wild-type (WT) animals. Furthermore, Nestorone treatment caused seizure exacerbation in the WT epileptic animals, but not in the PRKO epileptic animals.

SIGNIFICANCE

Activation of PRs expressed in the EC and hippocampus increased neuronal excitability and worsened seizures. These receptors may play a role in catamenial epilepsy.

Pharmacokinetics, metabolism and serum concentrations of progestins used in contraception

Many different forms of hormonal contraception are used by millions of women worldwide. These contraceptives differ in the dose and type of synthetic progestogenic compound (progestin) used, as well as the route of administration and whether or not they contain estrogenic compounds. There is an increasing awareness that different forms of contraception and different progestins have different side-effect profiles, in particular their cardiovascular effects, effects on reproductive cancers and susceptibility to infectious diseases. There is a need to develop new methods to suit different needs and with minimal risks, especially in under-resourced areas. This requires a better understanding of the pharmacokinetics, metabolism, serum and tissue concentrations of progestins used in contraception as well as the biological activities of progestins and their metabolites via steroid receptors. Here we review the current knowledge on these topics and identify the research gaps. We show that there is a paucity of research on most of these topics for most progestins. We find that major impediments to clear conclusions on these topics include a lack of standardized methodologies, comparisons between non-parallel clinical studies and variability of data on serum concentrations between and within studies. The latter is most likely due, at least in part, to differences in intrinsic characteristics of participants. The review highlights the importance of insight on these topics in order to provide the best contraceptive options to women with minimal risks.

Segesterone acetate serum levels with a regression model of continuous use of the segesterone acetate/ethinyl estradiol contraceptive vaginal system

OBJECTIVE

To predict serum segesterone (SA) and ethinyl estradiol (EE) levels after 364 days of hypothetical continuous use (without removal) of a cyclic contraceptive vaginal system (CVS) containing 0.15 mg SA and 0.013 mg EE.

STUDY DESIGN

We used pharmacokinetic (PK) data (n = 37) from a multicenter, open-label, nonrandomized study of healthy women (18-38 years) that used the CVS for 13 cycles in a 21 days-in/7 days-out regimen to develop a linear regression model to predict daily serum SA and EE levels for 364 days of continuous CVS use. We then determined residual SA/EE levels in vitro from 18 randomly chosen CVS used by women who completed 13 cycles. Serum SA and EE levels were also predicted for 364 days of continuous CVS use in another in vitro study.

RESULTS

After a hypothetical 364 days of continuous CVS use, we predicted daily mean serum levels to be 184 pmol/L (95% confidence interval [CI], 102‒332 pmol/L) for SA and 43 pmol/L (95% CI, 19‒95 pmol/L) for EE. We did predict that serum EE levels would not accumulate over time. Residual SA and EE in the CVS were 60% and 80% of the original load after 13 cycles, respectively.

CONCLUSION

The predicted serum SA level after 364 days of hypothetical continuous CVS use was comparable to reported levels at which no pregnancy occurred (>100 pmol/L), showing the potential of the CVS for one year of continuous use. Clinical trials on continuous CVS use are planned.

IMPLICATIONS

Based on statistical modeling, the long-term, user-controlled contraceptive vaginal system containing segesterone acetate and ethinyl estradiol may have the potential to provide effective pregnancy prevention if used continuously (without removal) for one year. Further investigation is warranted.

Progress in progestin-based therapies for neurological disorders

Hormone therapy, primarily progesterone and progestins, for central nervous system (CNS) disorders represents an emerging field of regenerative medicine. Following a failed clinical trial of progesterone for traumatic brain injury treatment, attention has shifted to the progestin Nestorone for its ability to potently and selectively transactivate progesterone receptors at relatively low doses, resulting in robust neurogenetic, remyelinating, and anti-inflammatory effects. That CNS disorders, including multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), spinal cord injury (SCI), and stroke, develop via demyelinating, cell death, and/or inflammatory pathological pathways advances Nestorone as an auspicious candidate for these disorders. Here, we assess the scientific and clinical progress over decades of research into progesterone, progestins, and Nestorone as neuroprotective agents in MS, ALS, SCI, and stroke. We also offer recommendations for optimizing timing, dosage, and route of the drug regimen, and identifying candidate patient populations, in advancing Nestorone to the clinic.

Long-Lasting, Patient-Controlled, Procedure-Free Contraception: A Review of Annovera with a Pharmacist Perspective

Annovera (segesterone acetate and ethinyl estradiol vaginal system) is a US Food and Drug Administration FDA-approved long-lasting, reversible contraceptive that is fully administered by the user and does not require a procedure for insertion or removal. The vaginal system is in the shape of a ring and contains low doses of a novel progestin, egesterone acetate, and ethinyl estradiol. It is made of silicone and is fully pliable and flexible. The vaginal system is reusable for 13 cycles, using a 21 days in/7 days out regimen, providing women with the ability to control their fertility. Particularly now during the COVID-19 pandemic when access to contraception has been further reduced, patients may benefit from a method that is both long-lasting and patient-controlled.

Simultaneous assay of segesterone acetate (Nestorone®), estradiol, progesterone, and estrone in human serum by LC-MS/MS

OBJECTIVE

To develop a method to simultaneously quantify the synthetic contraceptive progestin segesterone acetate (Nestorone®, NES) and the endogenous steroid hormones estradiol (E2), progesterone (P4), and estrone (E1) in human serum samples by liquid chromatography-tandem mass spectrometry (LC-MS/MS).

STUDY DESIGN

We analyzed 615 serum samples collected from 67 reproductive-age women actively using a contraceptive vaginal ring (CVR) designed to release NES (200 mcg/d) and E2 (75-200 mcg/d). Samples were taken prior to and up to 30 days after CVR insertion and analyzed for concentrations of NES, E2, P4, and E1 in human serum using a Shimadzu Nexera-LCMS-8050 LC-MS/MS platform. Precision, accuracy, and sensitivity for all analytes were determined across multiple assays.

RESULTS

The assay ranges for NES, E2, P4, and E1 in this analytical method were 10 pg/mL to 10 ng/mL with a lower limit of quantification of 10 pg/mL for all targets. Assay precisions were less than or equal to 14.5% and accuracies ranged from 87.0% to 110.8%. When applied to the 615 clinical samples, 550 samples had quantifiable concentrations of NES (value range 0.014-1471 ng/mL). Similarly, 595 samples had quantifiable concentrations of E2 (0.010-0.312 ng/mL), 596 samples had quantifiable concentrations of P4 (0.010-5.791 ng/mL), and 609 samples had quantifiable concentrations of E1 (0.010-0.416 ng/mL).

CONCLUSIONS

The LC-MS/MS platform results in a robust, accurate, and sensitive method for the simultaneous quantification of NES and endogenous steroid hormones in human serum.

IMPLICATIONS

The analytical method described allows for the simultaneous quantification of NES and endogenous steroids and can be used to monitor NES concentrations during clinical trials and subject adherence to treatment with NES.

Progesterone in the Brain: Hormone, Neurosteroid and Neuroprotectant

Progesterone has a broad spectrum of actions in the brain. Among these, the neuroprotective effects are well documented. Progesterone neural effects are mediated by multiple signaling pathways involving binding to specific receptors (intracellular progesterone receptors (PR); membrane-associated progesterone receptor membrane component 1 (PGRMC1); and membrane progesterone receptors (mPRs)) and local bioconversion to 3α,5α-tetrahydroprogesterone (3α,5α-THPROG), which modulates GABA_A receptors. This brief review aims to give an overview of the synthesis, metabolism, neuroprotective effects, and mechanism of action of progesterone in the rodent and human brain. First, we succinctly describe the biosynthetic pathways and the expression of enzymes and receptors of progesterone; as well as the changes observed after brain injuries and in neurological diseases. Then, we summarize current data on the differential fluctuations in brain levels of progesterone and its neuroactive metabolites according to sex, age, and neuropathological conditions. The third part is devoted to the neuroprotective effects of progesterone and 3α,5α-THPROG in different experimental models, with a focus on traumatic brain injury and stroke. Finally, we highlight the key role of the classical progesterone receptors (PR) in mediating the neuroprotective effects of progesterone after stroke.

A technology evaluation of Annovera: a segesterone acetate and ethinyl estradiol vaginal ring used to prevent pregnancy for up to one year

INTRODUCTION

The segesterone acetate and ethinyl estradiol contraceptive vaginal ring (SA/EE CVR) was FDA-approved in August 2018 and is now available in the U.S. The CVR is placed vaginally for 21 days followed by a 7-day ring-free interval, when withdrawal bleeding typically occurs. One ring can be used for up to a year (13 cycles).

AREAS COVERED

This review summarizes this novel method of contraception, including the delivery system and the hormonal components. We describe the potential market, how it is used, the pharmacokinetic properties of the device, and results of clinical trials including efficacy, bleeding profile, acceptability, and safety.

EXPERT OPINION

The SA/EE CVR represents the first long-lasting user-controlled hormonal contraceptive device. The bleeding pattern is highly favorable and consistent over the entire year and is associated with very low discontinuation. Efficacy and safety are similar to other methods of combined hormonal contraceptives. Unscheduled ring removals increase the risk of failure. Further studies are needed to evaluate continuous use of the ring for greater than 21 days, and potential non-contraceptive benefits of the ring such as reduced menstrual bleeding.

Development of Novel Male Contraceptives

Unintended pregnancy is surprisingly common, accounting for 40-50% of pregnancies worldwide. Contraception is the most effective means of preventing unintended pregnancy. Seventy percent of all contraceptives are used by women; however, some women are unable to use contraceptives due to health conditions or side effects. Many men wish to take a more active role family planning, but currently have only two effective male contraceptive options, condoms and vasectomy. Therefore, work to develop novel male contraceptives analogous to popular female methods, such as daily pills or long-acting shots and implants, is underway. This paper will briefly discuss the pros and cons of condoms and vasectomies, and then review the research into novel methods of male contraception.

Reprint of: Beyond contraception and hormone replacement therapy: Advancing Nestorone to a neuroprotective drug in the clinic

Neurological diseases such as ischemic stroke can be debilitating and have limited treatments available. The progestin Nestorone® (segesterone acetate) has been evaluated for use in birth control and hormone replacement therapy due to its potency and high affinity for the progesterone receptor. Interestingly, Nestorone also exerts neuroprotection in animals afflicted with various central nervous system diseases, including stroke, which implicates its potential for treating these maladies in clinical settings. In fact, a recent Brain Research paper by Tanaka and colleagues demonstrates Nestorone's ability to reduce infarct sizes and preclude functional impairments in rats subjected to ischemic stroke. This commentary highlights Nestorone's properties as a progestin, its neuroprotective capabilities in animal studies, and how the Tanaka team's findings and previous clinical trials contribute to Nestorone's translation into a therapeutic agent for stroke and other neurological diseases.

Progesterone receptor activation regulates seizure susceptibility

OBJECTIVE

Progesterone is a potent neuromodulator that exerts effects on the brain through neurosteroids, progesterone receptors (PRs), and other molecules. Whether PR activation regulates seizures is not known. We determined whether PR activation increased seizure susceptibility.

METHODS

Adult female rats that developed epilepsy following lithium-pilocarpine-induced status epilepticus (SE) were used. Seizures were recorded by continuous-video EEG and read by an individual blinded to the treatment of the animals. The animals were treated for a week with progesterone (50 mg/kg per day), and the effect of progesterone withdrawal on seizure frequency was assessed during the subsequent week. During the week of progesterone treatment, the animals were treated with PR antagonist RU-486 (10 mg/kg per day) or a vehicle control, which was administered 30 min before progesterone. In another set of animals, we determined the effect of the PR agonist Nestorone (3 mg/kg per day) on seizure frequency. The animals were treated with Nestorone or vehicle for a week, and seizure frequencies at baseline and during the treatment week were compared.

RESULTS

Progesterone withdrawal induced twofold increase in seizures in 57% of animals (n = 14). RU-486 treatment in combination with progesterone, prevented this increase, and a smaller fraction of animals (17%) experienced withdrawal seizures (n = 13). The specific activation of PRs by Nestorone also increased the seizure frequency. Forty-six percent (n = 14) of Nestorone-treated animals experienced at least a 50% increase in seizures compared to only 9% of the vehicle-treated animals (n = 11).

INTERPRETATION

PR activation increased seizure frequency in epileptic animals. Thus, PRs may be novel targets for treating catamenial epilepsy.

Efficacy of the 1-year (13-cycle) segesterone acetate and ethinylestradiol contraceptive vaginal system: results of two multicentre, open-label, single-arm, phase 3 trials

Background

A ring-shaped, contraceptive vaginal system designed to last 1 year (13 cycles) delivers an average of 0·15 mg segesterone acetate and 0·013 mg ethinylestradiol per day. We evaluated the efficacy of this contraceptive vaginal system and return to menses or pregnancy after use.

Methods

In two identically designed, multicentre, open-label, single-arm, phase 3 trials (one at 15 US academic and community sites and one at 12 US and international academic and community sites), participants followed a 21-days-in, 7-days-out segesterone acetate and ethinylestradiol contraceptive vaginal system schedule for up to 13 cycles. Participants were healthy, sexually active, non-pregnant, non-sterilised women aged 18–40 years. Women were cautioned that any removals during the 21 days of cyclic use should not exceed 2 h, and used daily paper diaries to record vaginal system use. Consistent with regulatory requirements for contraceptives, we calculated the Pearl Index for women aged 35 years and younger, excluding adjunctive contraception cycles, as the primary efficacy outcome measure. We also did intention-to-treat Kaplan-Meier life table analyses and followed up women who did not use hormonal contraceptives or desired pregnancy after study completion for 6 months for return to menses or pregnancy. The trials are registered with ClinicalTrials.gov, numbers NCT00455156 and NCT00263341.

Findings

Between Dec 19, 2006, and Oct 9, 2009, at the 15 US sites, and between Nov 1, 2006, and July 2, 2009, at the 12 US and international sites we enrolled 2278 women. Our overall efficacy analysis included 2265 participants (1130 in the US study and 1135 in the international study) and 1303 (57·5%) participants completed up to 13 cycles. The Pearl Index for the primary efficacy group was 2·98 (95% CI 2·13–4·06) per 100 woman-years, and was well within the range indicative of efficacy for a contraceptive under a woman's control. The Kaplan-Meier analysis revealed the contraceptive vaginal system was 97·5% effective, which provided further evidence of efficacy. Pregnancy occurrence was similar across cycles. All 290 follow-up participants reported return to menses or became pregnant (24 [63%] of 38 women who desired pregnancy) within 6 months.

Interpretation

The segesterone acetate and ethinylestradiol contraceptive vaginal system is an effective contraceptive for 13 consecutive cycles of use. This new product adds to the contraceptive method mix and the 1-year duration of use means that women do not need to return to the clinic or pharmacy for refills every few months.

Funding

Eunice Kennedy Shriver National Institute of Child Health and Human Development of the National Institutes of Health, the US Agency for International Development, and the WHO Reproductive Health Research Department.

Weight control is vital for patients with early-stage endometrial cancer or complex atypical hyperplasia who have received progestin therapy to spare fertility: a systematic review and meta-analysis

Objectives: This study aimed to identify potential prognostic factors for patients with complex atypical hyperplasia (CAH) or early-stage endometrial cancer (EC) who received progestin therapy to spare fertility and, thus, improve the management of this patient group. Materials and methods: The PubMed, PMC, EMBASE, Web of Science, and Cochrane databases were searched for correlational studies published in English. Studies that evaluated the prognosis of patients with CAH or early-stage EC were pooled for a systematic review and meta-analysis. Results: In total, 31 eligible studies, including 8 prospective and 23 retrospective studies involving 1099 patients, were included in this analysis. The most commonly used progestin agents were medroxyprogesterone acetate (MPA, 47.0%) and megestrol acetate (MA, 25.5%). The total complete response (CR) rate was 75.8% (833/1099), and the median time to CR with first-line progestin therapy was 6 months. In total, 294 (26.8%) patients who achieved CR became pregnant spontaneously (28 cases) or through assisted reproductive technology (127 cases). During the median follow-up of 39 months, 245 (22.3%) women developed recurrence. Only one patient (0.09%) died of the disease. The meta-analysis showed that compared to a BMI<25 kg/m² and CAH, a body mass index (BMI) ≥25 kg/m² (P=0.0004, odds ratios (OR), 0.4; 95% confidence interval, 0.3-0.6) and EC (P=0.0000, OR, 0.3; 95% confidence interval, 0.2-0.6) were significantly associated with a higher likelihood of a CR. Patients with a BMI≥25 kg/m² (P=0.0007, OR, 2.5; 95% confidence interval, 1.4-4.3), PCOS (P=0.0006, OR, 3.4; 95% confidence interval, 1.5-7.9), and EC (P=0.0344, OR, 2.8; 95% confidence interval, 1.4-5.3) had a significantly higher risk of recurrence. Conclusion: In general, patients with CAH or early-stage EC who were treated with progesterone therapy had a favorable prognosis. However, the recurrence risk was not insignificant. Weight control is crucial for improving the clinical management of this patient group.

Steroids in Stroke with Special Reference to Progesterone

Both sex and steroid hormones are important to consider in human ischemic stroke and its experimental models. Stroke initiates a cascade of changes that lead to neural cell death, but also activates endogenous protective processes that counter the deleterious consequences of ischemia. Steroids may be part of these cerebroprotective processes. One option to provide cerebroprotection is to reinforce these intrinsic protective mechanisms. In the current review, we first summarize studies describing sex differences and the influence of steroid hormones in stroke. We then present and discuss our recent results concerning differential changes in endogenous steroid levels in the brains of male and female mice and the importance of progesterone receptors (PR) during the early phase after stroke. In the third part, we give an overview of experimental studies, including ours, that provide evidence for the pleiotropic beneficial effects of progesterone and its promising cerebroprotective potential in stroke. We also highlight the key role of PR signaling as well as potential additional mechanisms by which progesterone may provide cerebroprotection.

Combined nestorone-testosterone gel suppresses serum gonadotropins to concentrations associated with effective hormonal contraception in men

BACKGROUND

Novel male-based contraceptives are needed to broaden family planning choices. A progestin, Nestorone^® (Nes) gel, plus a testosterone (T) gel suppresses sperm concentrations to levels associated with effective contraception in normal men. However, administration of two gels on different parts of the body daily is impractical.

OBJECTIVE

Compare the effectiveness of daily application of a single, combined 8.3 mg Nes-62.5 mg T gel (Nes-T) vs. 62.7 mg T gel to suppress serum FSH and LH concentrations to ≤1.0 IU/L (a threshold associated with suppression of sperm concentrations to ≤1 million and effective contraception) and to compare the pharmacokinetics of serum Nes and T concentrations between the gel groups.

DESIGN

We conducted a 28-day, double-blind, controlled trial of 44 healthy men randomized to daily Nes-T or T gel with measurement of hormones at baseline, treatment, and recovery and during 24-h pharmacokinetic studies on days 1 and 28 of treatment.

RESULTS

Of the subjects who met pre-defined inclusion criteria, 84% of the Nes-T group suppressed serum gonadotropin concentrations to ≤1.0 IU/L at days 21-28 vs. 16.7% in the T group (p < 0.001). On day 1, Nes concentrations rose significantly above baseline by 2 h and continued to rise up to 24 h after Nes-T gel application. Nes concentrations were not detectable in the T group. Serum total T concentrations rose and were significantly higher in the T gel group compared to the Nes-T group at 24 h on day 1 and days 11, 14, and 21 (p < 0.01). There were no serious adverse events in either group. About 80% of the subjects reported satisfaction with both gels.

CONCLUSION

Daily Nes-T gel effectively and safely suppresses serum gonadotropins and is acceptable to most men. It should be studied further in efficacy trials of hormonal male contraception.

Bone turnover markers in women participating in a dose-finding trial of a contraceptive vaginal ring releasing Nestorone and estradiol

OBJECTIVE

To evaluate changes in the bone turnover markers CTx and P1NP during 6 months' use of novel continuous contraceptive vaginal rings delivering Nestorone (NES) 200 mcg/day and three doses of estradiol (E2) (10, 20, and 40 mcg/day).

STUDY DESIGN

This randomized trial enrolled 189 women who used two consecutive vaginal rings over 180 days. Frequent blood sampling permitted analysis of NES, E2, CTx and P1NP concentrations. The bone-turnover marker analyses included only women with complete sampling and excluded women with characteristics that might interfere with accurate measurement of bone markers such as afternoon sampling, poor ring compliance or recent pregnancy. We evaluated the change from baseline to 6 months in CTx and P1NP, stratified by ring dose and by average circulating E2 concentrations.

RESULTS

One hundred fifty-one women completed the study, and 82 women had complete data available for the bone marker analyses; the three dosage groups were balanced with regard to baseline characteristics. E2 concentrations remained low throughout treatment, regardless of which dose ring the participant used. Individual CTx changes from baseline averaged 27±56% (p<.01). Similarly, individual P1NP changes averaged 11±33% (p=.04). These increases were within the premenopausal reference ranges, and unrelated to treatment dose or to circulating E2 concentrations.

CONCLUSIONS

The low E2 dose of these rings was associated with low E2 concentrations and modest increases in serum bone turnover makers. Because we have only 6-month bone turnover markers and no direct evidence of bone loss or bone density change, these results must be interpreted with caution.

IMPLICATIONS

Nestorone, a 19-norprogesterone derivative, leads to complete ovarian suppression, which should yield excellent contraceptive effectiveness. To prevent potential adverse effects on bone, the NES contraceptive ring should be combined with higher doses of E2 than were assessed in this study.

Segesterone acetate/ethinyl estradiol 12-month contraceptive vaginal system safety evaluation

OBJECTIVES

To evaluate safety outcomes from clinical studies of a 12-month contraceptive vaginal system (CVS) releasing an average of segesterone acetate (SA) 150 mcg and ethinyl estradiol (EE) 13 mcg daily.

STUDY DESIGN

We integrated clinical safety data from nine studies in which women used the CVS for 21 consecutive days and removed it for 7 days of each 28-day cycle. Four studies used the final manufactured CVS, including a 1-year pharmacokinetic study, two 1-year phase 3 trials and a second-year treatment extension study. We assessed safety by evaluating adverse events women reported in a daily diary. We also included data from focused safety studies evaluating endometrial biopsies, vaginal microbiology and liver proteins from one of the phase 3 studies.

RESULTS

The combined studies included 3052 women; 2308 women [mean age 26.7±5.1 years; mean body mass index (BMI) 24.1±3.7 kg/m²] received the final manufactured CVS, of whom 999 (43.3%) completed 13 cycles of use. Women using the final CVS most commonly reported adverse events of headache (n=601, 26%), nausea (n=420, 18%), vaginal discharge/vulvovaginal mycotic infection (n=242, 10%) and abdominal pain (n=225, 10%). Few (<1.5%) women discontinued for these complaints. Four (0.2%) women experienced venous thromboembolism (VTE), three of whom had risk factors for thrombosis [Factor V Leiden mutation (n=1); BMI>29 kg/m² (n=2)]. During 21,482 treatment cycles in the phase 3 studies evaluable for expulsion, women reported partial expulsions in 4259 (19.5%) cycles and complete expulsions in 1509 (7%) cycles, most frequently in the initial cycle [499/2050 (24.3%) and 190/2050 (9.3%), respectively]. Safety-focused studies revealed no safety concerns.

CONCLUSION

The 1-year SA/EE CVS has an acceptable safety profile. Additional studies are warranted in obese women at higher risk of VTE.

IMPLICATIONS

This 1-year contraceptive vaginal system represents a new long-term, user-controlled and procedure-free option with a safety profile similar to other combination hormonal contraceptives. The same precautions currently used for combination hormonal contraceptive prescriptions apply to this new contraceptive vaginal system.

Preventing secondary exposure to women from men applying a novel nestorone/testosterone contraceptive gel

BACKGROUND

Testosterone (T)/Nestorone (NES) combination gel is a potential transdermal male contraceptive that suppresses gonadotropins and spermatogenesis. Transfer of transdermal T from men to women can be prevented by washing or covering application sites with clothing.

OBJECTIVES

We hypothesized that showering or wearing a shirt over gel application sites would prevent secondary exposure of T and NES to a woman after close skin contact.

MATERIALS AND METHODS

Twelve healthy male and 12 healthy female participants were recruited. Men applied T/NES 62 mg/8 mg gel to their shoulders and upper arms. Two hours after application, female partners rubbed the application site for 15 min. Exposure in the female partner was assessed under three conditions: a shirt covered the application site; the man showered prior to skin contact; or without intervention to reduce transfer. Serum T and NES concentrations were measured by LC-MS/MS in serial blood samples for 24 h after gel exposure.

MAIN OUTCOMES

Change in female serum T and NES levels as measured by average concentration over 24 h (Cavg ).

RESULTS

Median female serum T Cavg was 23.9 ng/dL (interquartile range, 19.3, 33.9) with the shirt barrier and 26.7 ng/dL (20.7, 33.9) after showering, which was higher than baseline 20.9 ng/dL (16.7, 25.0), both p < 0.03) but lower than without intervention (58.2 ng/dL [30.9, 89.1], both p < 0.01). Female serum NES Cavg and maximum concentration were below the lower limit of quantification with the shirt barrier and after showering, but increased without intervention in six of 12 women (maximum concentration <60 pg/mL). Men had lower average serum NES levels after showering (47 pg/ml [20, 94] compared to no intervention (153.3 pg/mL [51, 241], p < 0.02).

CONCLUSION

Secondary transfer of T and NES occurs after intensive skin contact with the gel application site. Secondary transfer is decreased by a shirt barrier or showering before contact.

Human versus non-human sex steroid use in hormone replacement therapies part 1: Preclinical data

Prior to 2002, hormone replacement therapy (HRT) was considered to be an important component of postmenopausal healthcare. This was based on a plethora of basic, epidemiological and clinical studies demonstrating the health benefits of supplementation with human sex steroids. However, adverse findings from the Women's Health Initiative (WHI) studies that examined the 2 major forms of HRT in use in the US at that time - Premarin (conjugated equine estrogens; CEE) and Prempro (CEE + medroxyprogesterone acetate; MPA), cast a shadow over the use of any form of HRT. Here we review the biochemical and physiological differences between the non-human WHI study hormones - CEE and MPA, and their respective human counterparts 17β-estradiol (E₂) and progesterone (P₄). Preclinical data from the last 30 years demonstrate clear differences between human and non-human sex steroids on numerous molecular, physiological and functional parameters in brain, heart and reproductive tissue. In contrast to CEE supplementation, which is not always detrimental although certainly not as optimal as E₂ supplementation, MPA is clearly not equivalent to P₄, having detrimental effects on cognitive, cardiac and reproductive function. Moreover, unlike P₄, MPA is clearly antagonistic of the positive effects of E₂ and CEE on tissue function. These data indicate that minor chemical changes to human sex steroids result in physiologically distinct actions that are not optimal for tissue health and functioning.

Advances in contraceptive vaginal rings: what does the future hold?

INTRODUCTION

Contraceptive vaginal rings (CVRs) are good contraceptive options because they do not require skilled providers, are self-administered, and show a higher stability of drug diffusion.

AREAS COVERED

This article provides a review of the developments made with CVRs over the past number of years, while giving focus to the latest CVRs that have gone through clinical development. The author of the article also provides an expert perspective on the future of these useful therapeutic options.

EXPERT OPINION

Pharmacokinetic studies have shown that segesterone, an absorbable progestin that is used alone or in combination with ethinyl estradiol (EE) or E_2, is the CVR of choice at this present time. Indeed, segesterone has demonstrated safety and efficacy as a CVR and is also an appropriate option for lactating women, as they are not absorbed orally. However, good cycle control is important for improved CVR adherence. CVRs that allow the combination of more than one drug may unravel another multi-purpose use when combined with microbicides and could provide combined protection to women who wish to protect themselves from pregnancy and sexually transmitted infection.

Therapeutic progestin segesterone acetate promotes neurogenesis: implications for sustaining regeneration in female brain

OBJECTIVE

Neurogenesis is the principal regenerative mechanism to sustain the plasticity potential in adult brains. Decreased neurogenesis parallels the cognition decline with aging, and has been suggested as a common hallmark in the progression of many neurodegeneration diseases. We previously reported that acute exposure to segesterone acetate (ST-1435; Nestorone), alone or in combination with 17β-estradiol (E2), increased human neural stem cells proliferation and survival both in vitro and in vivo. The present study expanded our previous findings to investigate the more clinical related chronic exposure in combination with E2 on the regenerative capacity of adult brain.

METHODS

To mimic the chronic contraception exposure in women, 3-month old female mice (n = 110) were treated with ST-1435, with or without co-administration of E2, for 4 weeks. Neural cell proliferation and survival, and oligodendrocyte generation were assessed. The involvement of insulin-like growth factor 1 signaling was studied.

RESULTS

Our results demonstrated that chronic ST-1435 and E2 alone or in combination increased neurogenesis by a comparable magnitude, with minimum to no antagonistic or additive effects between ST-1435 and E2. In addition, chronic exposure of ST-1435 or ST-1435 + E2 stimulated oligodendrocyte generation, indicating potential elevated myelination. Insulin-like growth factor-1 (IGF-1) and IGF-1 receptor (IGF-1R) were also up-regulated after chronic ST-1435 and E2 exposure, suggesting the involvement of IGF-1 signaling as the potential underlined regulatory pathway transducing ST-1435 effect.

CONCLUSION

These findings provide preclinical evidence and mechanistic insights for the development of ST-1435 as a neuroregenerative therapy to promote intrinsic regenerative capacity in female brains against aging and neurodegenerative disorders.

Harnessing Androgen Receptor Pathway Activation for Targeted Alpha Particle Radioimmunotherapy of Breast Cancer

PURPOSE

The impact of androgen receptor (AR) activity in breast cancer biology is unclear. We characterized and tested a novel therapy to an AR-governed target in breast cancer.Experimental Design: We evaluated the expression of prototypical AR gene products human kallikrein 2 (hK2) and PSA in breast cancer models. We screened 13 well-characterized breast cancer cell lines for hK2 and PSA production upon in vitro hormone stimulation by testosterone [dihydrotestosterone (DHT)]. AR-positive lines were further evaluated by exposure to estrogen (17β-Estradiol) and the synthetic progestin D-Norgestrel. We then evaluated an anti-hK2-targeted radiotherapy platform (hu11B6), labeled with alpha (α)-particle emitting Actinium-225, to specifically treat AR-expressing breast cancer xenografts under hormone stimulation.

RESULTS

D-Norgestrel and DHT activated the AR pathway, while 17β-Estradiol did not. Competitive binding for AR protein showed similar affinity between DHT and D-Norgestrel, indicating direct AR-ligand interaction. In vivo production of hK2 was sufficient to achieve site-specific delivery of therapeutic radionuclide to tumor tissue at >20-fold over background muscle uptake; effecting long-term local tumor control.

CONCLUSIONS

[²²⁵Ac]hu11B6 targeted radiotherapy was potentiated by DHT and by D-Norgestrel in murine xenograft models of breast cancer. AR activity in breast cancer correlates with kallikrein-related peptidase-2 and can be activated by D-Norgestrel, a common contraceptive, and AR induction can be harnessed for hK2-targeted breast cancer α-emitter radiotherapy.

Continuous dosing of a novel contraceptive vaginal ring releasing Nestorone® and estradiol: pharmacokinetics from a dose-finding study

BACKGROUND

As part of a program to develop a novel estradiol-releasing contraceptive vaginal ring (CVR), we evaluated the pharmacokinetic (PK) profile of CVRs releasing segesterone acetate (Nestorone® (NES)) combined with one of three different estradiol (E2) doses.

STUDY DESIGN

A prospective, double-blind, randomized, multi-centered study to evaluate a 90-day CVR releasing NES [200mcg/day] plus E2, either 10mcg/day, 20mcg/day, or 40mcg/day in healthy reproductive-age women with regular cycles. Participants provided blood samples twice weekly for NES and E2 levels during the first 60 days (ring 1) and the last 30 days (ring 2) of use. A subset underwent formal PK assessments at ring initiation, ring exchange (limited PK), and study completion.

RESULTS

The main study enrolled 197 women; 22 participated in the PK substudy. Baseline characteristics between the main and PK participants were comparable, with an average BMI of 25.8 kg/m2 (SD 4.3). In the PK substudy, all three rings showed similar NES PK: mean area under the curve (AUC(0-72)) 34,181 pg*day/mL; concentration maximum (Cmax) 918 pg/mL; time to maximum concentration (Tmax) 3.5 h. For E2, the Cmax occurred at 2 h, and was significantly higher with the 20 mcg/day ring (mean 390 pg/mL); 10 mcg/day, 189 pg/mL, p=.003; 40 mcg/day, 189 pg/mL, p<.001), and declined rapidly to≤50 pg/mL for all doses by 24 h. For all subjects, the median E2 levels remained under 35 pg/mL during treatment.

CONCLUSION

PK parameters of NES were not affected when paired with different doses of E2, but E2 levels from all three doses were lower than anticipated and no dose response was observed.

IMPLICATIONS

While these novel estradiol-releasing combination contraceptive vaginal rings provided sustained release of contraceptive levels of Nestorone over 90 days, the E2 levels achieved were not consistent with bone protection, and a dose-response was not observed.