Elagolix, a novel, orally bioavailable GnRH antagonist under investigation for the treatment of endometriosis-related pain

A Systematic Review of the Psychosocial Impact of Endometriosis before and after Treatment

While endometriosis is a common gynecologic disease associated with infertility, the psychosocial impact of endometriosis has not been evaluated against various quality of life (QoL) instruments and compared with other chronic illnesses. We rigorously analyzed the psychosocial burden of endometriosis in adult women and compared standardized and validated QoL scores of women with and without endometriosis, before and following treatment, and against other chronic illnesses. We searched PubMed, PsychINFO Embase, and Cochrane Reviews and ClinicalTrials.gov from January 1990 to December 2022 for publications using a detailed list of search terms related to QoL, endometriosis, and questionnaires. Only English-language publications that evaluated the association between Endometriosis and QoL using standardized and validated questionnaires measured at baseline and following treatment were considered. Four reviewers first performed a title and abstract screening followed by full text-review to finalize included articles. QoL scores of women with endometriosis were measured at baseline and analyzed against women without endometriosis and women with endometriosis who had undergone treatment. Additionally, baseline endometriosis scores were assessed against the published QoL scores of populations with other chronic conditions. Assessment of risk of bias was performed in accordance with Cochrane and Newcastle-Ottawa Scale guidelines. A total of 30 articles were included in this review: 4 randomized trials and 26 observational studies. The diagnosis and experience of women with symptomatic endometriosis had an equal or worse QoL score than that of other chronic conditions including heart disease, diabetes, and breast cancer when compared using the 36-Item Short Form Survey and World Health Organization Quality of Life questionnaires. Evidence showed association between low QoL and infertility, sexual dysfunction, mental health struggles, physical pain, poor sleep and fatigue. QoL scores were lower at baseline compared to following treatment in the majority of these domains. Endometriosis is associated with significant psychosocial burden and impaired QoL scores across baseline measurements in comparison to controls and other chronic illnesses. Medical and surgical interventions significantly decreased experienced burdens and improved QoL of women with endometriosis.

Post-marketing safety concerns with elagolix: a disproportionality analysis of the FDA adverse event reporting system

OBJECTIVE

Elagolix is approved for the treatment of moderate-to-severe pain associated with endometriosis. However, the long-term safety of elagolix in a large sample of real-world patients is unknown.

METHODS

The U.S. Food and Drug Administration Adverse Event Reporting System (FAERS) reports were collected and analyzed from January 2019 to June 2023. Disproportionality analyses, including the reporting odds ratio (ROR), the proportional reporting ratio (PRR), the Bayesian confidence propagation neural network (BCPNN), and the multi-item gamma Poisson shrinker (MGPS) algorithms, were employed in data mining to quantify the signals of elagolix-related adverse events (AEs).

RESULTS

After removing the non-drug-related AE signals, we detected several AE signals such as hot flushes, bone pain, suicidal ideation, depression, and increased liver enzymes, which were known during the clinical trial phase. In addition to this, we detected several unexpected important AEs that were not mentioned in the drug insert, including cystitis interstitial, parosmia, and epiploic appendagitis. The median onset time of elagolix-associated AEs was 28.5 days.

CONCLUSION

Our study provides a comprehensive picture of the safety of elagolix in the post-marketing setting, while also identifying potential new AE signals. These findings emphasize the importance of continued monitoring of the potential risks of elagolix.

Experimental and new investigational drugs for the treatment of uterine fibroids

INTRODUCTION

Uterine fibroids, the most prevalent benign tumors among reproductive-age women, pose treatment challenges that range from surgical interventions to medical therapies for symptom control. Progestins and estroprogestins effectively manage uterine bleeding by suppressing dysfunctional endometrium over fibroids. While GnRH agonists represent a crucial milestone in symptom treatment, their prolonged use results in menopausal-like symptoms and irreversible bone mineral density loss. Advancements in understanding fibroid pathophysiology have prompted the exploration of new compounds to overcome current therapy limitations.

AREAS COVERED

This manuscript offers an updated overview of investigational drugs for symptomatic uterine fibroids.

EXPERT OPINION

Despite ulipristal acetate's well-established efficacy as a selective progesterone receptor modulator (SPRM) in fibroid treatment, its prescription has declined due to the rare but severe risk of liver damage. Oral GnRH antagonists, like elagolix, relugolix, and linzagolix, with their novel pharmacodynamic properties, are gaining traction in fibroid management, inducing a dose-dependent reduction in circulating sex hormone levels. Ongoing research on natural compounds, such as vitamin D and epigallocatechin gallate (EGCG), presents emerging options for treating uterine fibroids. This evolving landscape reflects the ongoing efforts to improve therapeutic outcomes for individuals with symptomatic uterine fibroids.

New Therapeutics in Endometriosis: A Review of Hormonal, Non-Hormonal, and Non-Coding RNA Treatments

Endometriosis is defined as endometrial-like tissue outside the uterine cavity. It is a chronic inflammatory estrogen-dependent disease causing pain and infertility in about 10% of women of reproductive age. Treatment nowadays consists of medical and surgical therapies. Medical treatments are based on painkillers and hormonal treatments. To date, none of the medical treatments have been able to cure the disease and symptoms recur as soon as the medication is stopped. The development of new biomedical targets, aiming at the cellular and molecular mechanisms responsible for endometriosis, is needed. This article summarizes the most recent medications under investigation in endometriosis treatment with an emphasis on non-coding RNAs that are emerging as key players in several human diseases, including cancer and endometriosis.

Does timing matter when initiating elagolix in a natural menstrual cycle?

Objective

To investigate the efficacy of elagolix when administered at different time points in a menstrual cycle.

Design

Clinical case series.

Setting

Academic reproductive endocrinology center.

Patients

Ovulatory women not desiring pregnancy.

Intervention(s)

Six doses of elagolix 200 mg were administered over 4 days, starting at 3 different points in a menstrual cycle: early follicular; late follicular; and midluteal. Serum follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2), and progesterone (P) concentrations were measured at baseline, during elagolix administration, and 1 day after the last dose. Transvaginal ultrasounds were performed to monitor follicle sizes.

Main Outcome Measure(s)

Serum FSH, LH, E2, and P.

Result(s)

Twelve women, four per group, completed the study. Subjects were 23–42 years of age. Demographics and ovarian reserve parameters were similar among participants. Elagolix suppressed FSH, LH, E2, and P when administered in the early follicular and midluteal phases but had mixed results when administered in the late follicular phase. Two participants demonstrated suppression of all four hormones. One participant ovulated, indicated by an increase in P concentration and development of a corpus luteum. A second participant did not ovulate yet demonstrated an increase in E2 concentration with growth of a dominant follicle. There were no significant differences in median percent change of hormone concentrations across study groups.

Conclusion(s)

The results of this study suggest that elagolix can suppress the hypothalamic–pituitary–ovarian axis when initiated at different points in a menstrual cycle. Optimal dosing and treatment window for consistent hormone suppression have yet to be determined.

Clinical Registration Number

NCT04060992

Pharmacokinetic, Safety, and Pharmacodynamic Properties of Teverelix Trifluoroacetate, a Novel Gonadotropin-Releasing Hormone Antagonist, in Healthy Adult Subjects

Teverelix trifluoroacetate is a decapeptide, gonadotropin-releasing hormone antagonist that binds competitively and reversibly to gonadotropin-releasing hormone receptors in the pituitary gland, resulting in immediate suppression of luteinizing hormone and follicle-stimulating hormone, which in turn causes a very rapid decrease in testosterone production in the Leydig cells of the testes in men and in estradiol in the ovaries in women. This phase 1 clinical study was an open-label, parallel-design, single-center, single-dose study in older, healthy male subjects. Following injection, teverelix is released into the systemic circulation in a biphasic manner. An initial rapid phase is followed by a slow-release phase thought to be due to the formation of a depot, which limits the diffusion of teverelix into the blood. The release characteristics differ significantly for the subcutaneous (SC) and intramuscular (IM) routes. Teverelix maximum concentration and exposure increased in an approximately dose-proportional manner across the 60 to 120 mg SC doses. All 3 pharmacodynamic end points (luteinizing hormone, follicle-stimulating hormone, and total testosterone) showed reductions that were more prolonged following the 90 mg IM administration compared to 90 mg SC administration.

Linzagolix: a new GnRH-antagonist under investigation for the treatment of endometriosis and uterine myomas

INTRODUCTION

Uterine myomas and endometriosis are benign hormone-dependent diseases affecting women of reproductive age. Substantial efforts have been made to develop innovative medical options for treating these gynecologic diseases. Elagolix and relugolix have been approved in some countries for treating endometriosis and myomas, respectively; however, linzagolix (OBE 2109, KLH 2109) is a new oral gonadotropin-releasing hormone (GnRH) antagonist in phase II-III trials. Treatment options for women with contraindications for hormonal therapies or who refuse particular options, are the driving force behind the development of new drugs in this area.

AREA COVERED

This drug evaluation highlights definitive and preliminary results from previous and ongoing studies of linzagolix for the treatment of endometriosis and myomas.

EXPERT OPINION

Linzagolix showed a dose-dependent and rapidly reversible action on the pituitary-gonadal axis. In a recent phase II trial (EDELWEISS), linzagolix significantly reduced pain related to endometriosis and improved quality of life at single daily doses of 75-200 mg. The preliminary results of international, double-blind phase III trials (PRIMROSE 1 and 2) reported its efficacy in treating heavy menstrual bleeding related to myomas with a good safety profile. Further studies will determine the necessity of add-back therapy during long-term use of linzagolix.

Safety and efficacy of elagolix (with and without add-back therapy) for the treatment of heavy menstrual bleeding associated with uterine leiomyomas: a systematic review and meta-analysis

Background

Heavy menstrual bleeding (HMB) is a common clinical finding in patients with uterine leiomyomas that can negatively impact their quality of life. Recently, a novel oral GnRH-antagonist (elagolix) has emerged as a possible therapeutic agent for this ailment. Herein data was pooled from clinical trials assessing the safety and efficacy of elagolix with and without add-back therapy.

Main text

PubMed and Cochrane library were systematically searched for RCTs that measured the efficacy and safety of elagolix for the treatment of uterine fibroid-associated HMB. All safety and efficacy endpoints were compared between elagolix-alone, elagolix w/add-back therapy, and placebo. The primary efficacy endpoint was defined as the number of women who achieved menstrual blood loss (MBL) < 80 ml and a reduction in MBL from baseline of > 50% at the end of treatment. Secondary outcomes assessed included change in hemoglobin levels, incidence suppression of bleeding and amenorrhea, and the incidence of adverse events. The random effects model was used to pool data, and heterogeneity was assessed using I2.

Our search identified 4 clinical trials meeting our PICO criteria, with a total of 916 patients. Analysis of the primary outcome revealed that elagolix-alone was the most effective treatment compared to both placebo (LOR = 3.47, CI = 3.03–3.91, p = 0.000, I2 = 0.0%) and add-back therapy (LOR = 0.64, CI = 0.12–1.16, p = 0.016, I2 = 43.1%). Furthermore, both elagolix groups (irrespective of add-back therapy) observed a significant improvement in post-treatment hemoglobin levels as compared to the placebo group (elagolix-alone vs PBO: LOR = 1.44, CI = 0.66–2.22, I2 = 66.0%, p = 0.000; elagolix-w/add-back therapy vs PBO: LOR = 1.22, CI = 0.78–1.66, I2 = 0.0%, p = 0.000). Concerning safety, while elagolix without add-back therapy had the highest overall incidence of adverse effects (elagolix-alone vs placebo LOR = 0.84, CI = 0.48–1.20, I2 = 7.8%, p = 0.000; elagolix-alone vs elagolix-w/add-back LOR = 0.68, CI = 0.09–1.26, p = 0.024, I2 = 64.6%), the incidence of serious (life threatening) adverse events between all 3 treatment groups was not statistically different. The inclusion of add-back therapy with elagolix made the treatment noticeably safer (elagolix-w/add-back vs placebo: LOR = 0.19, CI = − 0.10 to 0.48, I2 = 0.0%, p = 0.194) without seriously compromising its efficacy.

Conclusion

High-quality evidence from 4 trials suggests that elagolix is an effective treatment for leiomyoma-associated HMB, with a marked improvement in all efficacy endpoints. Furthermore, the inclusion of add-back therapy in the treatment regimen should be considered as it mitigates the hypoestrogenic effects of elagolix.

Elagolix in the treatment of heavy menstrual bleeding associated with uterine fibroids in premenopausal women

INTRODUCTION

Uterine fibroids (UFs) are the most common benign tumor arising from myometrium of reproductive age women, with significant financial burden estimated in hundreds of billions of dollars. Unfortunately, there are limitations in available long-term treatment options. Thus, there is a large unmet need in the UF space for noninvasive therapeutics.

AREAS COVERED

Authors reviewed the literature available for elagolix; an orally bioavailable, second-generation, non-peptide gonadotropin-releasing hormone (GnRH) antagonist recently approved by the US Food and Drug Administration (FDA) in combination with estradiol/norethindrone acetate for the management of heavy menstrual bleeding associated with UFs in premenopausal women.

EXPERT OPINION

The utility of new-generation oral GnRH-antagonists, such as elagolix, relugolix and linzagolix, is offering a new potential opportunity for the future therapy of UFs: elagolix has been the most studied drug of this class for treating benign gynecological diseases, including endometriosis and UFs, for which it has been US FDA-approved in 2018 and 2020, respectively.

First-in-Human, Double-Blind, Randomized Controlled Trial of an Oral Dose of GnRH Antagonist TU2670 in Healthy Women

OBJECTIVE

To evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics of TU2670, a novel orally active, nonpeptide gonadotropin-releasing hormone (GnRH) antagonist administered to healthy female participants.

METHODS

This was a first-in-human, multicenter, phase 1, randomized, double-blind, placebo-controlled, single-dose ascending trial that took place in multiple medical centers. A total of 16 healthy premenopausal women (23 to 45 years of age) were randomized and received 20, 40, 80, and 160 mg TU2670 (GnRH antagonist) or placebo 7 days (±1 day) after the onset of menstrual bleeding. We performed a noncompartmental analysis for pharmacokinetic parameters and calculated relative minimum concentration values (Cmin, % Baseline) of serum pharmacodynamic (PD) markers (luteinizing hormone [LH], follicle-stimulating hormone [FSH], and estradiol).

RESULTS

There were no significant differences among treatments with respect to vital signs, electrocardiography, adverse events, ovulation test results, and ultrasonography. The median Tmax of TU2670 occurred 0.75 to 1.00 hours after dosing, and concentrations then declined, with a mean apparent half-life (t1/2) of 3.0 to 5.9 hours. AUClast (17.7-417.9 ng·h/mL) and Cmax (8.1-95.4 ng/mL) increased in a dose-dependent manner. The PD analysis after a single administration of TU2670 revealed dose-dependent suppression of LH, FSH, and estradiol. Maximal suppression of the pre-dose baseline (%) was 58% to 82% at 6 to 8 hours for LH, 28% to 39% at 6 to 12 hours for FSH, and 34% to 82% at 12 to 24 hours for estradiol.

CONCLUSION

The single administration of TU2670 in healthy premenopausal women was well tolerated and resulted in the dose-dependent suppression of LH, FSH, and estradiol, suggesting rapid and significant inhibition of pituitary and ovarian hormones.

Vilaprisan, a New Selective Progesterone Receptor Modulator in Uterine Fibroid Pharmacotherapy-Will it Really be a Breakthrough?

BACKGROUND

Vilaprisan (VPR) is a new orally available selective progesterone receptor modulator (SPRM), with anti-proliferative activity against uterine fibroids (UFs). It definitively causes suppression of ovulation and inhibition of proliferation of endometrial, myometrial and UF cells.

PURPOSE

This review aims to summarize current knowledge on VPR from all studies, including clinical trials, conducted to date and to contextualize the potential role of VPR in future medical regimens for the treatment of UFs.

METHODS

We performed a literature search in PubMed US National Library of Medicine and Google Scholar databases. Both databases were extensively searched for all original and review articles/book chapters as well as congress abstracts published in English until July 2019. The use of VPR for UF therapy was identified by using the keywords: "uterine fibroids" and "vilaprisan".

RESULTS

In phase I and II clinical trials, VPR was shown to be effective in ameliorating UF-related clinical symptoms, especially abnormal or excessive uterine bleeding and in shrinking UFs. The tolerability of VPR is roughly similar to that of ulipristal acetate (UPA) and it tends to be more favorable than that of GnRH-agonists.

CONCLUSION

Presently, all trials examining the utility of VPR for the treatment of UF are halted; likely, due to the recently reported cases of hepato-toxicity with UPA, in addition to non reassuring toxicology results from preclinical long-term testing on rodents, carried out in parallel with late stage testing on humans. An accurate summary of robust data related to the safety of VPR is urgently needed to draw definitive conclusions on the future clinical development of this drug for UF therapy.

The potential role of elagolix for treating uterine bleeding associated to uterine myomas

INTRODUCTION

Uterine myomas represents a widespread gynecological disease of women in reproductive age. Although surgery remains the first choice for treating most patients, in the last years, new medical approaches have been considered in order to ameliorate heavy menstrual bleeding (HMB) related to their presence. Elagolix is a second-generation gonadotropin-releasing hormone (GnRH) antagonist under investigation for the long-term treatment of uterine myomas.

AREAS COVERED

The aim of this drug evaluation is to give a complete overview of pharmacokinetic and pharmacodynamic data on elagolix for treating HMB related to uterine myomas and to report the results of the current clinical trials in this setting.

EXPERT OPINION

In two previous phase II studies, this drug succeeded in ameliorating blood loss and quality of life of patients affected by uterine myomas with a good safety profile. Three phase III trials (ELARIS UF-I, UF-II, and EXTEND) investigated the efficacy, tolerability, and safety of elagolix at 300 mg twice daily with add-back therapy. The primary endpoint, consisting in the reduction in HMB compared to placebo, was met in the majority of patients under treatment. Currently, elagolix is under investigation in two other ongoing multicenter phase III clinical studies.

Uterine fibroids: an update on current and emerging medical treatment options

Uterine fibroids are the most common gynecological disorder, classically requiring surgery when symptomatic. Although attempts at finding a nonsurgical cure date back to centuries, it is only around the middle of the last century that serious attempts at a medical treatment were carried out. Initially, both progestins and estrogen–progestin combinations have been utilized, although proof of their usefulness is lacking. A major step forward was achieved when peptide analogs of the GnRH were introduced, first those with superagonist properties and subsequently those acting as antagonists. Initially, the latter produced side effects preventing their routine utilization; eventually, this problem was overcome following the synthesis of cetrorelix. Because both types of analogs produce hypoestrogenism, their use is limited to a maximum of 6 months and, for this reason, today they are utilized as an adjuvant treatment before surgery with overall good results. Over the last decade, new, nonpeptidic, orally active GnRH-receptor blockers have also been synthesized. One of them, Elagolix, is in the early stages of testing in women with fibroids. Another fundamental development has been the utilization of the so-called selective progesterone receptor modulators, sometimes referred to as “antiprogestins”. The first such compound to be applied to the long-term treatment of fibroids was Mifepristone; today, this compound is mostly used outside of Western Countries, where the substance of choice is Ulipristal acetate. Large clinical trials have proven the effectiveness of Ulipristal in the long-term medical therapy of fibroids, although some caution must be exercised because of the rare occurrence of liver complications. All selective progesterone receptor modulators produce unique endometrial changes that are today considered benign, reversible, and without negative consequences. In conclusion, long-term medical treatment of fibroids seems possible today, especially in premenopausal women.

New insights on the pathogenesis of endometriosis and novel non-surgical therapies

Endometriosis is a disease of theories, but none has succeeded to explain the whole picture. Most widely available drugs for endometriosis aim to relieve symptoms and improve fertility. Unfortunately, many short and long-term side-effects are associated with the treatments. To overcome this problem, researchers have developed many novel therapeutic agents, including non-invasive technique. We aim to provide new insights on pathogenesis model and novel non-surgical treatments for endometriosis, including drugs already available in the market and also drugs which are still under research. Seven novel treatment modalities are recognized, namely dienogest, aromatase inhibitor (AI), gonadotrophine-releasing hormone (GnRH) antagonist, anti tumor necrosing factor (TNF)-α, selective estrogen receptor modulator (SERM), selective progesterone receptor modulator (SPRM), and high-intensity focused ultrasound (HIFU). Dienogest, AI, and GnRH antagonists are effective novel treatments with good tolerance and safety. SERM and SPRM show inconsistent results, while anti-TNF-α is still in the animal experimental stage. HIFU is a potential futuristic treatment. However, it is still a long way until this technology is truly applicable.

Gonadotropin-Releasing Hormone Receptor Antagonist Mono- and Combination Therapy With Estradiol/Norethindrone Acetate Add-Back: Pharmacodynamics and Safety of OBE2109

Context

OBE2109 is a potent, oral gonadotropin-releasing hormone receptor antagonist being developed for the treatment of sex-hormone-dependent diseases in women.

Objective

We assessed the pharmacodynamics and safety of OBE2109 alone and combined with estradiol (E2)/norethindrone acetate (NETA) add-back therapy on E2 levels and vaginal bleeding.

Design, Setting, and Participants

This was a single-center, open-label, randomized, parallel-group study in 76 healthy premenopausal women.

Interventions

Women were randomly assigned to take the following doses (in milligrams) once daily for 6 weeks: OBE2109, 100 or 200; or OBE2109/E2/NETA, 100/0.5/0.1, or 100/1.0/0.5, or 200/1.0/0.5.

Main Outcome Measures

E2 concentrations, bleeding pattern, exploratory bone metabolism biomarkers, and adverse events.

Results

OBE2109 100 mg and 200 mg alone reduced E2 levels to reach median levels of 19.5 and 3.2 pg/mL, respectively, at week 4. Median E2 levels after combined OBE2109/add-back therapy ranged between 25 and 40 pg/mL. OBE2109 100 mg or 200 mg alone induced amenorrhea. By day 15, >85% of women had no vaginal bleeding during the last 4 weeks of treatment. Add-back therapy partially impaired bleeding control: The highest amenorrhea rate (53%) was observed with OBE2109 100 mg/1.0 mg/0.5 mg. The addition of E2/NETA, particularly at 1 mg/0.5 mg, mitigated the increase of two bone markers induced by OBE2109 200 mg.

Conclusion

OBE2109 promptly lowered E2 levels. Add-back therapy may be required to prevent adverse effects on bone in women treated with the 200-mg dose (at 100 mg in some women). These results provide a basis for OBE2109 regimen selection to treat sex-hormone-dependent diseases.

Recent Development of Non-Peptide GnRH Antagonists

The decapeptide gonadotropin-releasing hormone, also referred to as luteinizing hormone-releasing hormone with the sequence (pGlu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH₂) plays an important role in regulating the reproductive system. It stimulates differential release of the gonadotropins FSH and LH from pituitary tissue. To date, treatment of hormone-dependent diseases targeting the GnRH receptor, including peptide GnRH agonist and antagonists are now available on the market. The inherited issues associate with peptide agonists and antagonists have however, led to significant interest in developing orally active, small molecule, non-peptide antagonists. In this review, we will summarize all developed small molecule GnRH antagonists along with the most recent clinical data and therapeutic applications.

Alternative Oral Agents in Prophylaxis and Therapy of Uterine Fibroids-An Up-to-Date Review

Uterine fibroids (UFs) are the most common tumors of the female genital tract. The effect of UFs on the quality of life and the overall cost of treatment are significant issues worldwide. Tumor size and location are the two specific factors which influence the occurrence of symptoms, the need for, and method of, treatment (some tumors require surgery while some can be treated with selected drugs). Primary prevention and treatment of early UF disease are worthy goals that might have a great impact on health care systems. Several treatments and prophylactic methods can be used in this endeavor. This publication presents current data about lesser-known substances which may have a beneficial effect on the treatment or prophylaxis of UFs and can be administered orally, serving as an alternative to (or complement of) surgery or selective progesterone receptor modulators (SPRMs). Early prevention and treatment of UFs in women from high-risk groups should be our priority. Innovative forms of UF management are under intensive investigation and may be promising options in the near future. Many of them evaluated vitamin D, paricalcitol, epigallocatechin gallate (EGCG), elagolix, aromatase inhibitors (AIs), and cabergoline and deemed them to be safe and effective. The next step in such projects should be properly constructed randomized control trials (RCTs), carried out by successive phases.

Adverse bone effects of medications used to treat non-skeletal disorders

There is a growing list of medications used to treat non-skeletal disorders that cause bone loss and/or increase fracture risk. This review discusses glucocorticoids, drugs that reduce sex steroids, antidiabetic agents, acid-reducing drugs, selective serotonin reuptake inhibitors, and heparin. A number of drugs are known to cause bone loss, increase fracture risk, or both. These drugs should be used in the lowest dose necessary to achieve the desired benefit and for the shortest time necessary, but in many cases, long-term treatment is required. Effective countermeasures are available for some.

Expected Next-Generation Drugs Under Development in Relation to Voiding Symptoms

New drug development is a high-risk venture, but if successful, will bring great revenues to those willing to accept the risk. In the field of urology, in particular for lower urinary tract symptoms (LUTS), the recent successful landing of drugs (e.g., mirabegron, botulinum toxin A, and tadalafil) has resulted in increased interest in new drug development. Benign prostatic hyperplasia and overactive bladder syndrome, representative LUTS diseases, are attractive targets because of their prevalence and market size in the field of urology. Additionally, the awareness about new stream of research is very important not only because of the market size and economic factors, but also because to keep steady attention to these research for the researcher’s. We have reviewed a selection of new drugs currently under development for the treatment of the two aforementioned diseases and hope to offer urologists an overview of the current situation and future directions in the field of urology.

Research development of a new GnRH antagonist (Elagolix) for the treatment of endometriosis: a review of the literature

PURPOSE

Limitated studies have reported the efficacy of GnRH antagonist on endometriosis symptoms. The aim of our study was to review all available trials to investigate the medical treatment of endometriosis with only GnRH antagonists, with special attention to pharmacodynamic activity, safety, and efficacy.

METHODS

Pub Med and Sciencedirect database were searched using terms of "endometriosis treatment", "GnRH antagonist", and "Elagolix". The search was limited to clinical studies published in English. Title and abstract were screened to identify relevant articles.

RESULTS

Five studies covering use of GnRH antagonist were found. A phase 1 study evaluated the safety, pharmacokinetics, and inhibitory effects on gonadotropins and estradiol of single dose and 7 day elagolix administration to healthy premenopausal women; two phase II studies evaluated efficacy in patient with endometriosis. Moreover, there are two Phase III clinical trials just completed.

CONCLUSION

GnRH antagonists may have the advantage of oral administration and lower incidence of adverse events. Currently, only Phase II studies have been published demonstrating promising results in terms of efficacy, safety, and tolerability. From the results of the phase III studies, elagolix may become a valuable addition to the armamentarium of pharmacological agents to treat endometriosis-related pain.

Overview of elagolix for the treatment of endometriosis

INTRODUCTION

Suppression of sex-steroid secretion is required in a variety of gynecological conditions. This can be achieved using gonadotropin releasing hormone (GnRH) agonists that bind pituitary gonadotropin receptors and antagonize the link-receptor of endogenous GnRH, inhibiting the mechanism of GnRH pulsatility. On the other hand, GnRH antagonists immediately reduce gonadal steroid levels, avoiding the initial stimulatory phase of the agonists. Potential benefits of GnRH antagonists over GnRH agonists include a rapid onset and reversibility of action. Older GnRH antagonists are synthetic peptides, obtained by modifications of certain amino acids in the native GnRH sequence. They require subcutaneous injections, implantation of long-acting depots. The peptide structure is responsible for histamine-related adverse events and the tendency to elicit hypersensitivity reactions.

AREAS COVERED

Research has worked towards the development of non-peptidic molecules exerting antagonist action on GnRH. They are available for oral administration and may have a more beneficial safety profile in comparison with peptide GnRH antagonists. This article focuses on the data of the literature about elagolix, a novel non-peptidic GnRHantagonist, in the treatment of endometriosis.

EXPERT OPINION

Elagolix demonstrated efficacy in the management of endometriosis-associated pain and had an acceptable safety and tolerability profile. However, further studies are necessary to evaluate its non-inferiority in comparison with other endometriosis's treatments.

Endometriosis: where are we and where are we going?

Endometriosis currently affects ~5.5 million reproductive-aged women in the U.S. with symptoms such as painful periods (dysmenorrhea), chronic pelvic pain, pain with intercourse (dyspareunia), and infertility. It is defined as the presence of endometrial tissue outside the uterine cavity and is found predominately attached to sites within the peritoneal cavity. Diagnosis for endometriosis is solely made through surgery as no consistent biomarkers for disease diagnosis exist. There is no cure for endometriosis and treatments only target symptoms and not the underlying mechanism(s) of disease. The nature of individual predisposing factors or inherent defects in the endometrium, immune system, and/or peritoneal cavity of women with endometriosis remains unclear. The literature over the last 5 years (2010-2015) has advanced our critical knowledge related to hormones, hormone receptors, immune dysregulation, hormonal treatments, and the transformation of endometriosis to ovarian cancer. In this review, we cover the aforementioned topics with the goal of providing the reader an overview and related references for further study to highlight the progress made in endometriosis research, while concluding with critical areas of endometriosis research that are urgently needed.

GnRH and GnRH receptors in the pathophysiology of the human female reproductive system

BACKGROUND

Human reproduction depends on an intact hypothalamic-pituitary-gonadal (HPG) axis. Hypothalamic gonadotrophin-releasing hormone (GnRH) has been recognized, since its identification in 1971, as the central regulator of the production and release of the pituitary gonadotrophins that, in turn, regulate the gonadal functions and the production of sex steroids. The characteristic peculiar development, distribution and episodic activity of GnRH-producing neurons have solicited an interdisciplinary interest on the etiopathogenesis of several reproductive diseases. The more recent identification of a GnRH/GnRH receptor (GnRHR) system in both the human endometrium and ovary has widened the spectrum of action of the peptide and of its analogues beyond its hypothalamic function.

METHODS

An analysis of research and review articles published in international journals until June 2015 has been carried out to comprehensively summarize both the well established and the most recent knowledge on the physiopathology of the GnRH system in the central and peripheral control of female reproductive functions and diseases.

RESULTS

This review focuses on the role of GnRH neurons in the control of the reproductive axis. New knowledge is accumulating on the genetic programme that drives GnRH neuron development to ameliorate the diagnosis and treatment of GnRH deficiency and consequent delayed or absent puberty. Moreover, a better understanding of the mechanisms controlling the episodic release of GnRH during the onset of puberty and the ovulatory cycle has enabled the pharmacological use of GnRH itself or its synthetic analogues (agonists and antagonists) to either stimulate or to block the gonadotrophin secretion and modulate the functions of the reproductive axis in several reproductive diseases and in assisted reproduction technology. Several inputs from other neuronal populations, as well as metabolic, somatic and age-related signals, may greatly affect the functions of the GnRH pulse generator during the female lifespan; their modulation may offer new possible strategies for diagnostic and therapeutic interventions. A GnRH/GnRHR system is also expressed in female reproductive tissues (e.g. endometrium and ovary), both in normal and pathological conditions. The expression of this system in the human endometrium and ovary supports its physiological regulatory role in the processes of trophoblast invasion of the maternal endometrium and embryo implantation as well as of follicular development and corpus luteum functions. The GnRH/GnRHR system that is expressed in diseased tissues of the female reproductive tract (both benign and malignant) is at present considered an effective molecular target for the development of novel therapeutic approaches for these pathologies. GnRH agonists are also considered as a promising therapeutic approach to counteract ovarian failure in young female patients undergoing chemotherapy.

CONCLUSIONS

Increasing knowledge about the regulation of GnRH pulsatile release, as well as the therapeutic use of its analogues, offers interesting new perspectives in the diagnosis, treatment and outcome of female reproductive disorders, including tumoral and iatrogenic diseases.