Ovarian response and embryo ploidy following oral micronized progesterone-primed ovarian stimulation versus GnRH antagonist protocol. A prospective study with repeated ovarian stimulation cycles.

STUDY QUESTION: Is there any difference in ovarian response and embryo ploidy following progesterone-primed ovarian stimulation (PPOS) using micronized progesterone or GnRH antagonist protocol? SUMMARY ANSWER: Pituitary downregulation with micronized progesterone as PPOS results in higher number of oocytes retrieved and a comparable number of euploid blastocysts to a GnRH antagonist protocol. WHAT IS KNOWN ALREADY: Although the GnRH antagonist is considered by most the gold standard protocol for controlling the LH surge during ovarian stimulation (OS) for IVF/ICSI, PPOS protocols are being increasingly used in freeze-all protocols. Still, despite the promising results of PPOS protocols, an early randomized trial reported potentially lower live births in recipients of oocytes resulting following downregulation with medroxyprogesterone acetate as compared with a GnRH antagonist protocol. The scope of the current prospective study was to investigate whether PPOS with micronized progesterone results in an equivalent yield of euploid blastocysts to a GnRH antagonist protocol. STUDY DESIGN, SIZE, DURATION: In this prospective study, performed between September 2019 to January 2022, 44 women underwent two consecutive OS protocols within a period of 6 months in a GnRH antagonist protocol or in a PPOS protocol with oral micronized progesterone. PARTICIPANTS/MATERIALS, SETTING, METHODS: Overall, 44 women underwent two OS cycles with an identical fixed dose of rFSH (225 or 300 IU) in both cycles. Downregulation in the first cycles was performed with the use of a flexible GnRH antagonist protocol (0.25 mg per day as soon as one follicle of 14 mm) and consecutively, after a washout period of 1 month, control of LH surge was performed with 200 mg of oral micronized progesterone from stimulation Day 1. After the completion of both cycles, all generated blastocysts underwent genetic analysis for aneuploidy screening (preimplantation genetic testing for aneuplody, PGT-A). MAIN RESULTS AND THE ROLE OF CHANCE: Comparisons between protocols did not reveal differences between the duration of OS. The hormonal profile on the day of trigger revealed statistically significant differences between protocols in all the tested hormones except for FSH: with significantly higher serum E2 levels, more elevated LH levels and higher progesterone levels in PPOS cycles as compared with antagonist cycles, respectively. Compared with the GnRH antagonist protocol, the PPOS protocol resulted in a significantly higher number of oocytes (12.7 ± 8.09 versus 10.3 ± 5.84; difference between means [DBM] -2.4 [95% CI -4.1 to -0.73]), metaphase II (9.1 ± 6.12 versus 7.3 ± 4.15; DBM -1.8 [95% CI -3.1 to -0.43]), and 2 pronuclei (7.1 ± 4.99 versus 5.7 ± 3.35; DBM -1.5 [95% CI -2.6.1 to -0.32]), respectively. Nevertheless, no differences were observed regarding the mean number of blastocysts between the PPOS and GnRH antagonist protocols (2.9 ± 2.11 versus 2.8 ± 2.12; DBM -0.07 [95% CI -0.67 to 0.53]) and the mean number of biopsied blastocysts (2.9 ± 2.16 versus 2.9 ± 2.15; DBM -0.07 [95% CI -0.70 to 0.56]), respectively. Concerning the euploidy rates per biopsied embryo, a 29% [95% CI 21.8-38.1%] and a 35% [95% CI 26.6-43.9%] were noticed in the PPOS and antagonist groups, respectively. Finally, no difference was observed for the primary outcome, with a mean number of euploid embryos of 0.86 ± 0.90 versus 1.00 ± 1.12 for the comparison of PPOS versus GnRh antagonist. LIMITATIONS, REASONS FOR CAUTION: The study was powered to detect differences in the mean number of euploid embryos and not in terms of pregnancy outcomes. Additionally, per protocol, there was no randomization, the first cycle was always a GnRH antagonist cycle and the second a PPOS with 1 month of washout period in between. WIDER IMPLICATIONS OF THE FINDINGS: In case of a freeze-all protocol, clinicians may safely consider oral micronized progesterone to control the LH surge and patients could benefit from the advantages of a medication of oral administration, with a potentially higher number of oocytes retrieved at a lower cost, without any compromise in embryo ploidy rates. STUDY FUNDING/COMPETING INTEREST(S): This research was supported by an unrestricted grant from Theramex. N.P.P. has received Research grants from Merck Serono, Organon, Ferring Pharmaceutical, Roche, Theramex, IBSA, Gedeon Richter, and Besins Healthcare; honoraria for lectures from: Merck Serono, Organon, Ferring Pharmaceuticals, Besins International, Roche Diagnostics, IBSA, Theramex, and Gedeon Richter; consulting fees from Merck Serono, Organon, Besins Healthcare, and IBSA. M.d.M.V., F.M., and I.R. declared no conflicts of interest. TRIAL REGISTRATION NUMBER: The study was registered at Clinical Trials Gov. (NCT04108039).

Meta-analysis of trigger timing in normal responders undergoing GnRH antagonist ovarian hyperstimulation protocol.

IMPORTANCE: The first meta-analysis focused only on gonadotropin-releasing hormone (GnRH) antagonists, which helped determine the effect of delay trigger on pregnancy outcomes. OBJECTIVE: To evaluate the impact of delay trigger compared with standard trigger in normal responders undergoing GnRH antagonist protocol in improving pregnancy outcomes. METHODS: Studies published before April 2023 in PubMed, EMBASE, Cochrane Library, Web of Science, CNKI, Wanfang, VIP and CBM databases were searched. Randomized controlled trials (RCTs) and cohort studies conducted in normal responders reporting the efficacy of delay trigger using GnRH antagonist protocol were included. Data were combined to calculate mean differences (MD) for continuous variables and odd ratios (OR) for categorical variables with their corresponding 95% confidence intervals (CIs). Heterogeneity was assessed using Cochran's Q test. RESULTS: Endpoints, including clinical pregnancy rate (CPR), live birth rate (LBR), the number of oocyte retrievals and embryos, and fertilization rate, were analyzed. Six (6) clinical studies (4 RCTs and 2 cohort studies) with 1,360 subjects were included. The pooled results showed that the number of oocyte retrievals (MD: 1.20, 95% CI: 1.10, 1.30, p < 0.01), fertilization rate (MD: 0.64, 95% CI: 0.29, 0.99, p < 0.01) and days of stimulation (MD: 0.95; 95% CI: 0.54, 1.37; p < 0.01) in the delay trigger group was significantly higher than that in the standard trigger group. However, there was no significant difference in the number of embryos (MD: 0.19, 95% CI: -0.29, 0.67, p = 0.44), CPR (OR: 1.12; 95% CI: 0.72, 1.75; p = 0.062), and LBR (OR: 1.23; 95% CI: 0.90, 1.66; p = 0.19) between the two trigger groups. CONCLUSION: Delaying trigger time in GnRH antagonist protocol increased the number of oocytes retrieved but not the number of embryos. Furthermore, delay trigger shot was not associated with a clinical benefit towards CPR and LBR in women who underwent fresh embryo transfer cycles. TRIAL REGISTRATION: The International Prospective Register of Systematic Reviews (PROSPERO), registration number: CRD42023413217.

Sex-dependent regulation of social avoidance by oxytocin signaling in the ventral tegmental area.

It has been hypothesized that oxytocin increases the salience of social stimuli, whether the valence is positive or negative, through its interactions with the ventral tegmental area (VTA). Indeed, oxytocin neurons project to the VTA and activate dopamine neurons that are necessary for social experiences with positive valence. Surprisingly, though, there has not been an investigation of the role of oxytocin in the VTA in mediating social experiences with negative valence (e.g., social stress). Given that there are sex differences in how oxytocin regulates the salience of positively-valenced social interactions, we hypothesized that oxytocin acting in the VTA also alters the salience of social stress in a sex-dependent manner. To test this, female and male Syrian hamsters were site-specifically infused with either saline, oxytocin (9 µM), or oxytocin receptor antagonist (90 µM) into the VTA. Subjects were then exposed to either no defeat or a single, 15 min defeat by one RA. The day following social defeat, subjects underwent a 5 min social avoidance test. There was an interaction between sex and drug treatment, such that the oxytocin antagonist increased social avoidance compared to saline treatment in socially stressed females, while oxytocin decreased social avoidance compared to saline treatment in socially stressed males. Contrary to expectations, these results suggest that oxytocin signaling generally acts to decrease social avoidance, regardless of sex. These sex differences in the efficacy of oxytocin and oxytocin receptor antagonists to alter negatively-valenced social stimuli, however, should be considered when guiding pharmacotherapies for disorders involving social deficits.

The effects of flexible short protocol with gonadotropin-releasing hormone antagonist on preventing premature ovulation in poor responders.

PURPOSE: The proportion of patients with poor ovarian response (POR) is increasing, but effective treatment remains a challenge. To control the hidden peaks of luteinizing hormone (LH) and premature ovulation for poor responders, this study investigated the efficacy of flexible short protocol (FSP) with gonadotropin-releasing hormone antagonist (GnRH-ant) on trigger day. METHODS: The 662 cycles of POR patients were retrospectively analyzed. The cohort was divided into control and intervention groups. The intervention group (group A) with 169 cycles received a GnRH-ant given on trigger day. The control (group B) with 493 cycles received only FSP. The clinical outcomes of the two groups were compared. RESULTS: Compared with group B, with gonadotropin-releasing hormone antagonist (GnRH-ant) on trigger day in group A the incidences of spontaneous premature ovulation decreased significantly (2.37% vs. 8.72%, P < 0.05). The number of fresh embryo-transfer cycles was 45 in group A and 117 in group B. There were no significant differences in clinical outcomes, including implantation rate, clinical pregnancy rate, live birth rate and the cumulative live birth rate (12.0% vs. 9.34%; 22.22% vs. 21.93%; 17.78% vs. 14.91%; 20.51% vs. 20%, respectively; P > 0.05) between the two group. CONCLUSION: FSP with GnRH-ant addition on trigger day had no effect on clinical outcomes, but could effectively inhibit the hidden peaks of luteinizing hormone (LH) and spontaneous premature ovulation in POR. Therefore, it is an advantageous option for POR women.

Steroid profile in patients with breast cancer and in mice treated with mifepristone.

Progesterone receptors (PRs) are biomarkers used as prognostic and predictive factors in breast cancer, but they are still not used as therapeutic targets. We have proposed that the ratio between PR isoforms A and B (PRA and PRB) predicts antiprogestin responsiveness. The MIPRA trial confirmed the benefit of 200 mg mifepristone, administered to patients with tumors with a high PRA/PRB ratio, but dose-ranging has not been conducted. The aim of this study was to establish the plasma mifepristone levels of patients from the MIPRA trial, along with the resultant steroid profiles, and compare these with those observed in mifepristone-treated mice using therapeutic schemes able to induce the regression of experimental mammary carcinomas with high PRA/PRB ratios: 6 mg pellets implanted subcutaneously, or daily doses of 12 mg/kg body weight. The plasma levels of mifepristone and other 19 plasma steroids were measured by liquid chromatography-tandem mass spectometry. In mifepristone-treated mice, plasma levels were lower than those registered in mifepristone-treated patients (i.e. day 7 after treatment initiation, pellet-treated mice: 8.4 ± 3.9 ng/mL; mifepristone-treated patients: 300.3 ± 31.7 ng/mL (mean ± s.d.; P < 0.001)). The increase in corticoid related steroids observed in patients was not observed in mifepristone-treated mice. The increase in progesterone levels was the most significant side effect detected in mifepristone-treated mice after 14 or 21 days of treatment, probably due to an ovarian compensatory effect not observed in postmenopausal patients. We conclude that in future clinical trials using mifepristone, the possibility of lowering the standard daily dose of 200 mg should be considered.

A review of phase II and III drugs for the treatment and management of endometriosis.

INTRODUCTION: Endometriosis is an estrogen-dependent disease that gives rise to pelvic pain and infertility. Although estroprogestins and progestins currently stand as the first-line treatments for this condition, demonstrating efficacy in two-thirds of patients, a significant portion of individuals experience only partial relief or symptom recurrence following the cessation of these therapies. The coexistence of superficial, deep endometriosis, and ovarian endometriomas, as three distinct phenotypes with unique pathogenetic and molecular characteristics, may elucidate the current heterogeneous biological response to available therapy. AREAS COVERED: The objective of this review is to furnish the reader with a comprehensive summary pertaining to phase II-III hormonal treatments for endometriosis. EXPERT OPINION: Ongoing research endeavors are directed toward the development of novel hormonal options for this benign yet debilitating disease. Among them, oral GnRH antagonists emerge as a noteworthy option, furnishing rapid therapeutic onset without an initial flare-up; these drugs facilitate partial or complete estrogen suppression, and promote prompt ovarian function recovery upon discontinuation, effectively surmounting the limitations associated with previously employed GnRH agonists. Limited evidence supports the use of selective estrogen and progesterone receptor modulators. Consequently, further extensive clinical research is imperative to garner a more profound understanding of innovative targets for novel hormonal options.

A premature luteinizing hormone surge without elevated progesterone levels has no adverse effect on cumulative live birth rate in patient undergoing a flexible GnRH antagonist protocol: a retrospective study.

BACKGROUND: A premature luteinizing hormone (LH) surge refers to an endogenous LH peak that occurs before follicle maturation or human chorionic gonadotropin injection in the process of controlled ovarian hyperstimulation. The effect of premature LH surge on pregnancy outcomes in fresh embryo transfer cycles is still controversial. The aim of this study was to explore the effect of a premature LH surge without elevated progesterone levels on the cumulative pregnancy rate (CPR) and cumulative live birth rate (CLBR) of patients during a flexible GnRH antagonist protocol. METHODS: A total of 730 infertile women undergoing IVF/ICSI were recruited for this retrospective study. Only women who either delivered a live infant or had no remaining frozen embryos after a single stimulation cycle were included in the analysis. During the study period, each patient underwent a flexible GnRH antagonist protocol. Women were divided into two groups according to the presence or absence of a premature LH surge. The primary outcome measures were the CPR and CLBR per ovarian stimulation cycle. The secondary outcome measures were the number of oocytes retrieved, fertilization rate, good-quality embryo rate, and clinical pregnancy rate. RESULTS: Ninety-one women (12.47%) experienced a premature LH surge without elevated progesterone levels, and the other 639 (87.53%) women were assigned to the control group. The numbers of oocytes retrieved and fertilization rate were significantly greater in the premature LH surge group than in the control group. There was no significant difference between groups in the good-quality embryo rate, clinical pregnancy rate or live birth rate in the fresh embryo transfer cycle. The primary outcome measures, the CPR and CLBR per ovarian stimulation cycle, were not significantly different between the premature LH surge group and the control group. According to the analysis stratified by ovarian response (normal or high), there were no significant differences in pregnancy outcomes between the groups with and without a premature LH surge. CONCLUSIONS: The retrospective study demonstrated that the patients experiencing a transient premature LH surge without progesterone elevation had equivalent pregnancy outcomes with those without a premature LH surge on a flexible GnRH antagonist protocol. The present conclusions need to be further validated in a prospective well-designed large-scale study.

Perfluorohexane sulfonate (PFHxS) disturbs the estrous cycle, ovulation rate, oocyte cell communication and calcium homeostasis in mice.

Perfluoroalkyl substances are man-made chemicals with ample consumer and industrial applications. They are widely used and are resistant to environmental and metabolic degradation. Several studies have evaluated the effects of Perfluorohexane sulfonate on reproduction. However, there are few reports exploring the cell and molecular mechanisms of its toxicity in the ovary. The aim of this study was to investigate the effects of PFHxS exposure on the estrous cycle, ovulation rate, and the underlying mechanisms of action in female mice in vivo. The animals received a single sub-lethal dose of PFHxS (25.1 mg/kg, 62.5 mg/kg) or vehicle and were stimulated to obtain immature cumulus cell-oocyte complexes (COCs) from the ovaries, or superovulated to develop mature COCs. To evaluate oocyte physiology, Gap-junction intercellular communication (GJIC) was analyzed in immature COCs and calcium homeostasis was evaluated in mature oocytes. PFHxS exposure prolonged the estrous cycle and decreased ovulation rate in female mice. Connexins, Cx43 and Cx37, were downregulated and GJIC was impaired in immature COCs, providing a possible mechanism for the alterations in the estrous cycle and ovulation. No morphological abnormalities were observed in the mature PFHxS-exposed oocytes, but calcium homeostasis was affected. This effect is probably due, at least partially, to deregulation of the endoplasmic reticulum calcium modulator, Stim1. These mechanisms of ovarian injury could explain the reported correlation among PFHxS levels and subfertility in women undergoing fertility treatments.

Suppressive effects of linzagolix, a novel non-peptide antagonist of gonadotropin-releasing hormone receptors, in experimental endometriosis model rats.

Endometriosis is an oestrogen-dependent disease in which endometrial-like tissue grows outside the uterus in women of reproductive age. Accordingly, control of oestradiol (E2) levels is an effective treatment for endometriosis. Because gonadotropin-releasing hormone (GnRH) is the main controller of E2 secretion, control of GnRH signalling by GnRH antagonism is an effective strategy for the treatment of sex hormone-dependent diseases such as endometriosis. The purpose of the present study was to evaluate the effects of the potent, orally available and selective GnRH antagonist linzagolix on experimental endometriosis in rats and compare them with those of dienogest, which is used clinically to treat endometriosis. Experimental endometriosis was induced in female rats at the proestrus stage of the oestrous cycle via autotransplantation of endometrial tissue into the renal subcapsular space. Linzagolix significantly decreased cyst volumes compared with the control group at doses of 50 mg/kg or more. Indeed, a suppressive effect of dienogest on cyst volume was observed only at the highest dose evaluated (1 mg/kg). The effective concentration of linzagolix, calculated as the free form of the last-observed drug concentration, was ~1 µmol/L in endometriosis model rats. The present study also reveals that linzagolix exerts a sustained inhibitory effect on E2 secretion, indicating that the suppressive effect on endometriosis cyst volumes could be attributed to its pharmacological suppression of GnRH signalling and serum E2 concentrations. Altogether, our findings indicate that linzagolix may be a useful therapeutic intervention for hormone-dependent diseases including endometriosis.

Effect of anti-estrogen and anti-progesterone on spermatogenesis, testosterone production and expression of steroidogenic enzyme genes in adult male rats.

The present study was planned to investigate the anti-spermatogenic and anti-steroidogenic effects of Clomiphene Citrate (CC) an anti-estrogen and Mifepristone (MT) an anti-progesterone in the testis of male rats. Following the oral administration of 1.0 mg and 5.0 mg/kg b.w/day of each for the duration of 30 and 60 days, quantitation of spermatogenesis, RIA for serum and intra-testicular testosterone levels, western blotting and RT-PCR for expression of StAR, 3ß-HSD and P450arom enzymes in the testis was done. Clomiphene Citrate at 5.0 mg/kg b.w/day for 60 days significantly reduced testosterone (T) levels however the effect was not significant with the lower doses. Reproductive parameters in animals treated by Mifepristone remained mostly unaffected, however, a significant decline in testosterone levels and altered expression of selected genes was observed in 5.0 mg for the 30d treatment group. Clomiphene Citrate at higher doses affected the weights of the testis and secondary sex organs. Seminiferous tubules revealed hypo-spermatogenesis with a significant decrease in the number of maturing germ cells and a reduction in tubular diameter. Attenuation in serum testosterone was associated with the downregulation of expression in StAR, 3ß-HSD, and P450arom mRNA and protein levels in the testis even after 30 d of CC administration. The results indicate that the anti-estrogen (Clomiphene Citrate) but not anti-progesterone (Mifepristone) induces hypo-spermatogenesis in rats which are associated with a downregulation of expression of two of the steroidogenic enzymes, 3ß-HSD and P450arom mRNA and StAR protein.

Targeting the Progesterone Receptor in Breast Cancer: Mind the Short Form!

SUMMARY: The presurgical window of opportunity trial (WOT) MIPRA provides evidence that neoadjuvant treatment with the progesterone receptor (PR) antagonist mifepristone (RU486) may benefit patients with estrogen receptor-positive (ER+) breast cancer characterized by a high ratio of PR-A versus PR-B isoform (>1.5), suggesting that PR may be targeted in a subset of patients. See related article by Elía et al., p. 866.

Repositioning Mifepristone as a Leukaemia Inhibitory Factor Receptor Antagonist for the Treatment of Pancreatic Adenocarcinoma.

Pancreatic cancer is a leading cause of cancer mortality and is projected to become the second-most common cause of cancer mortality in the next decade. While gene-wide association studies and next generation sequencing analyses have identified molecular patterns and transcriptome profiles with prognostic relevance, therapeutic opportunities remain limited. Among the genes that are upregulated in pancreatic ductal adenocarcinomas (PDAC), the leukaemia inhibitory factor (LIF), a cytokine belonging to IL-6 family, has emerged as potential therapeutic candidate. LIF is aberrantly secreted by tumour cells and promotes tumour progression in pancreatic and other solid tumours through aberrant activation of the LIF receptor (LIFR) and downstream signalling that involves the JAK1/STAT3 pathway. Since there are no LIFR antagonists available for clinical use, we developed an in silico strategy to identify potential LIFR antagonists and drug repositioning with regard to LIFR antagonists. The results of these studies allowed the identification of mifepristone, a progesterone/glucocorticoid antagonist, clinically used in medical abortion, as a potent LIFR antagonist. Computational studies revealed that mifepristone binding partially overlapped the LIFR binding site. LIF and LIFR are expressed by human PDAC tissues and PDAC cell lines, including MIA-PaCa-2 and PANC-1 cells. Exposure of these cell lines to mifepristone reverses cell proliferation, migration and epithelial mesenchymal transition induced by LIF in a concentration-dependent manner. Mifepristone inhibits LIFR signalling and reverses STAT3 phosphorylation induced by LIF. Together, these data support the repositioning of mifepristone as a potential therapeutic agent in the treatment of PDAC.

New local ganirelix sustained release therapy for uterine leiomyoma. Evaluation in a preclinical organ model.

Currently, there is a limited number of treatment options available for patients with symptomatic leiomyomas, and surgical removal is by far the most frequent procedure. Previous studies found that GnRH agonists and antagonists acting through GnRH receptors led to cell death and decreased extracellular synthesis in cultured leiomyoma cells. In this study, we encapsulated the GnRH antagonist ganirelix in PLGA microspheres contained in an alginate scaffold that also supports a leiomyoma ex vivo tissue explant. Microspheres maintained ganirelix concentration stably during six days of culture, inducing significant cell death in 50-55% of tumor cells. Although no changes were observed in the expression of extracellular matrix genes, a decreased expression of the Nuclear Factor of Activated T cells 5, a transcription factor involved in osmotic stress and tumor size. Interestingly, all tumors analyzed experienced apoptosis independently of the original driver mutation. These data indicate that local therapy of ganirelix would induce tumor reduction in a wide range of uterine leiomyomas.

Effect of Dual Trigger In Vitro Fertilization and Intracytoplasmic Sperm Injection During the Gonadotropin-releasing Hormone-Antagonist Cycle on Final Oocyte Maturation and Cumulative Live Birth Rate in Women with Diminished Ovarian Reserve.

OBJECTIVE: It is well known that a dual trigger treatment can improve clinical outcomes of in vitro fertilization (IVF) in high or normal ovarian responders. However, it is not clear whether dual triggering also benefits patients with diminished ovarian reserve (DOR). The aim of this study was to investigate whether a dual trigger treatment of gonadotropin-releasing hormone (GnRH) agonist combined with human chorionic gonadotropin (hCG) for final follicular maturation improves the cumulative live birth rate (CLBR) during the GnRH-antagonist cycle in patients with DOR. METHODS: This retrospective study included patients with DOR who received a GnRH-antagonist protocol during IVF and intracytoplasmic sperm injection (IVF-ICSI) cycles at Peking University People's Hospital from January 1, 2017 through December 31, 2017. Oocyte maturation was triggered by GnRH combined with hCG (n=110) or hCG alone (n=71). Embryos were transferred on the third day after oocyte retrieval or during a subsequent freeze-thaw cycle. Patients were followed up for 3 years. RESULTS: The dual trigger treatment did not affect CLBR, which is an overall determinant of the success rate of assisted reproductive technology (ART). Women in the dual trigger group had significantly higher rates of fertilization than those in the hCG group (90.1% vs. 83.9%, P=0.040). CONCLUSION: Dual trigger with GnRH agonist and hCG did not improve CLBR in patients with DOR, but did slightly improve fertilization rate, oocyte count, and embryo quality.

Linzagolix: First Approval.

Linzagolix (Yselty®) is an orally administered, selective, non-peptide small molecule gonadotrophin releasing hormone (GnRH) receptor antagonist that is being developed by Kissei Pharmaceutical for the treatment of uterine fibroids and endometriosis in women of reproductive age. Linzagolix binds to and blocks the GnRH receptor in the pituitary gland, modulating the hypothalamic pituitary-gonadal axis and dose-dependently reducing serum luteinising hormone and follicle-stimulating hormone production and serum estradiol levels. In June 2022, linzagolix was approved for the treatment of moderate to severe symptoms of uterine fibroids in adult women of reproductive age in the EU. Linzagolix is under regulatory review the USA for this indication and is in phase 3 clinical development in the treatment of pain associated with endometriosis. This article summarizes the milestones in the development of linzagolix leading to this first approval for the treatment of moderate to severe symptoms of uterine fibroids in adult women of reproductive age.

Outcomes of a GnRH Agonist Trigger Following a GnRH Antagonist or Flexible Progestin-Primed Ovarian Stimulation Cycle.

A suggested explanation for the pituitary-suppressive effects of progestin-primed ovarian stimulation cycles (PPOS) is pituitary luteinizing hormone (LH) depletion with progestin exposure during the follicular phase. The GnRH agonist (GnRHa) trigger releases endogenous LH from the pituitary, and if the LH depletion theory is correct, the response to the agonist trigger would be dampened in PPOS cycles. In this study, we compared the performance of the GnRHa trigger after PPOS and GnRH antagonist ovarian stimulation cycles. All women who underwent ovarian stimulation with the GnRH antagonist or flexible PPOS (fPPOS) and received a GnRH agonist trigger were eligible for inclusion. Outcomes included number of metaphase-II (MII) oocytes retrieved per cycle, rates of empty follicle syndrome, maturation, fertilization, blastulation, and cumulative clinical pregnancy per stimulation cycle. During the screening period, there were 166 antagonists and 58 fPPOS cycles triggered with a GnRH agonist. Groups were matched for potential confounders using propensity score matching. Progestin-downregulated cycles had 19% high mature oocyte yield (median: 14 vs. 19 MII oocytes, P = 0.03). Cumulative ongoing pregnancy or live birth rates were estimated after matching for transferred embryo count, and rates were similar between GnRH antagonist and fPPOS group (57.0% vs. 62.1%, P = 0.68). However, the number of remaining blastocysts was higher in the fPPOS group (median: 5.0 vs. 6.0, P < 0.001). LH levels were higher in fPPOS cycles compared to GnRH antagonist cycles up to the trigger day (P < 0.001). After the GnRHa trigger, fPPOS cycles were associated with a steeper LH surge compared with antagonist cycles (P = 0.02). Higher endogenous gonadotropin levels through the stimulation period and an LH surge of higher magnitude following a GnRHa trigger suggest a milder pituitary suppression by fPPOS, which needs to be confirmed in larger samples. It appears that progestins do not deplete pituitary LH reserves and a GnRHa trigger is usable after PPOS in women with high ovarian reserve.

Pharmacological characterization of linzagolix, a novel, orally active, non-peptide antagonist of gonadotropin-releasing hormone receptors.

Control of gonadotropin-releasing hormone (GnRH) signalling is an effective strategy for the treatment of sex hormone-dependent diseases. GnRH analogues have been widely used for treating these diseases; however, initial stimulation or complete suppression of GnRH signalling by GnRH analogues results in the occurrence of several distinct adverse effects. Accordingly, we aimed to discover small molecule GnRH antagonists with superior pharmacokinetic and pharmacodynamic profiles. Linzagolix is a potent, orally available, and selective GnRH antagonist. Here, we reported the pharmacological characterization of linzagolix in vitro and in vivo. Linzagolix selectively binds to the GnRH receptor and inhibits GnRH-stimulated signalling, in a manner comparable to cetrorelix, a peptide GnRH antagonist. Because the inhibitory effect of the gonad axis is useful for the treatment of gynaecological conditions such as endometriosis and uterine fibroids, we investigated the effect of orally administrated linzagolix on the gonadal axis in ovariectomized and intact cynomolgus monkeys. In ovariectomized monkeys, linzagolix immediately suppressed the serum luteinizing hormone concentration at doses over 1 mg/kg, indicating dose-dependent inhibition that correlated with serum linzagolix concentrations. In intact female monkeys, repeated linzagolix administration suppressed hormone surges and ceased or prolonged menstrual cycles. Furthermore, all animals presenting arrested menstrual cycles following linzagolix treatment showed recovery of hormone secretion and regular menstrual cycles after administration periods ended. Our results demonstrated that linzagolix has potential as a novel agent for reproductive-age women suffering from sex hormone-dependent diseases.

Effect of early GnRH antagonist administration on assisted reproductive technique outcomes in normal responders.

One of the main questions in assisted reproductive techniques is how to prevent premature LH surge using a variety of protocols depending on either pituitary down-regulation, in GnRH agonist protocols, or by receptors blockage, in GnRH protocols. It is possible to say that GnRH protocols are most popular nowadays. The study aimed to assess the effectiveness of early antagonist administration during days ≤6 and later antagonist administration on days >6 on assisted reproductive outcomes. Women admitted to the ART Department at the High Institute for Infertility Diagnosis and ART, Al-Nahrain University, Baghdad, Iraq were included in the study. Reproductive outcomes were evaluated in early ≤6 and late >6 antagonist administration in a total of 44 normal responders, as follows. Sandwich protocols in 14 patients that received antagonists in the first 3 days of the follicular phase and conventional flexible antagonist protocol in 30 patients. We compared the outcomes between the two groups. There were no differences between early antagonist administration ≤6 and late >6 days in the number of MII oocytes, 2PN, the number of transferred embryos, grades of the embryos, and pregnancy rates. However, there were statistically significant differences between the duration of stimulation and the total Gonadotropin dose required. There was no effect of antagonist administration on days ≤6 and >6 on controlled ovarian stimulation on assisted reproductive outcomes.

Progesterone-primed ovarian stimulation in oocyte donation: a model for elective fertility preservation?

RESEARCH QUESTION: Does type of LH peak suppression (progesterone-primed ovarian stimulation [PPOS] versus gonadotrophin releasing hormone [GnRH] antagonist) affect oocyte competence, embryo development and live birth rates in recipients of vitrified donated oocytes? DESIGN: Retrospective cohort study conducted between 2016 and 2018, involving 187 recipient cycles of donated vitrified oocytes. Oocyte donors were stimulated under LH suppression with desogestrel for PPOS (DSG group) or ganirelix GnRH antagonist (ANT group). Recipients younger than 50 years received vitrified oocytes from DSG donation cycles (DSG-R) or ANT donation cycles (ANT-R). RESULTS: A mean of 10.07 ± 3.54 oocytes per recipient were warmed (survival rate of 80.7%), and 5.90 ± 2.89 were fertilized (fertilization rate 72.6%). Out of 187 recipients, 168 achieved embryo transfers. No significant differences were found in warming survival rates, fertilization rates and embryo development between DSG-R and ANT-R groups. Ninety-four clinical pregnancies and 81 live births were achieved. No statistically significant differences were found in clinical pregnancy rates (47.7% versus 52.5, P = 0.513) and live birth rates (39.5% versus 46.5%, P = 0.336) per recipient cycle between DSG-R and ANT-R, respectively. Multivariable logistic regression was applied to assess the effect of treating oocyte donors. Live birth rate adjusted for associated factors was not statistically different between vitrified oocytes from DSG or ANT (OR 0.74, 95% CI 0.37 to 1.47). CONCLUSION: Reproductive outcomes of recipients of vitrified oocytes are not affected by donor PPOS treatment. PPOS is suitable for suppressing LH peak in elective fertility preservation and in freeze-all strategies.

GnRH antagonist weakens endometrial stromal cells growth ability by decreasing c-kit receptor expression.

BACKGROUND: Several surveys have reported that patients treated with gonadotropin-releasing hormone antagonist (GnRH-ant) protocol showed a significantly lower rate of implantation and clinical pregnancy compared to GnRH agonist (GnRH-a) protocol during in vitro fertilization-fresh embryo transfer. Subsequent studies imputed this poor outcome to the negative effects of GnRH-ant on endometrial receptive. However, the mechanisms were not fully understood. METHODS: The clinical data of 2815 patients undergoing fresh embryo transfer in our center were analyzed. Human endometrial stromal cells (ESCs) from healthy women undergoing elective pregnancy termination of a normal pregnancy at 8-10 weeks gestation were treated with GnRH-analogs or imatinib (c-kit receptor inhibitor). CCK8 and Flow cytometry were used to investigated the growth ability of ESCs. Immunofluorescence staining and western blot was used to detected the target proteins. RESULTS: The clinical data showed that the endometrial thickness on HCG Day were significantly lower in GnRH-ant group. Although no difference of embryo quality in these two groups, GnRH-ant group showed remarkably decreased rate of HCG positive, embryo implantation and pregnancy. Moreover, GnRH-ant significantly reduced the proliferation and induced the apoptosis of ESCs. Furthermore, the expression and activation of c-kit receptor, which played pivotal roles during embryo implantation, were observably decreased by GnRH-ant. Inhibiting the activation of c-kit by imatinib remarkably suppressed the proliferation and promoted the apoptosis of ESCs. Additionally, the phosphorylation of AKT and expression of Cyclin D1, which were closely related with cellular growth, were distinctly lessened after treating with imatinib. CONCLUSIONS: In summary, our study showed that GnRH-ant weakened the activization of c-kit receptor by decreasing its expression, causing the impaired growth ability of ESCs. Our findings provided a new insight into the effects of GnRH-ant on endometrium.