Pharmacodynamic effects and plasma pharmacokinetics of single doses of cetrorelix acetate in healthy premenopausal women

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.

Effects of pulsatile intravenous follicle-stimulating hormone treatment on ovarian function in women with obesity

OBJECTIVE

To establish conditions for effective hypothalamic suppression in women with normal and high body mass index (BMI) and test the hypothesis that intravenous (IV) administration of pulsatile recombinant follicle-stimulating hormone (rFSH) can overcome the clinically evident dysfunctional pituitary-ovarian axis in women with obesity.

DESIGN

Prospective interventional study.

SETTING

Academic medical center.

PATIENT(S)

Twenty-seven normal-weight women and 27 women with obesity, who were eumenorrheic and aged 21-39 years.

INTERVENTION(S)

Two-day frequent blood sampling study, in early follicular phase, before and after cetrorelix suppression of gonadotropins and exogenous pulsatile IV rFSH administration.

MAIN OUTCOME MEASURE(S)

Serum inhibin B and estradiol (E2) levels (basal and rFSH stimulated).

RESULT(S)

A modified gonadotropin-releasing hormone antagonism protocol effectively suppressed production of endogenous gonadotropins in women with normal and high BMIs, providing a model to address the functional role of FSH in the hypothalamic-pituitary-ovarian axis. The IV rFSH treatment resulted in equivalent serum levels and pharmacodynamics in normal-weight women and those with obesity. However, women with obesity exhibited reduced basal levels of inhibin B and E2 and a significantly decreased response to FSH stimulation. The BMI was inversely correlated with serum inhibin B and E2. In spite of this observed deficit in ovarian function, pulsatile IV rFSH treatment in women with obesity resulted in E2 and inhibin B levels comparable with those in normal-weight women, in the absence of exogenous FSH stimulation.

CONCLUSION(S)

Despite normalization of FSH levels and pulsatility by exogenous IV administration, women with obesity demonstrate ovarian dysfunction with respect to E2 and inhibin B secretion. Pulsatile FSH can partially correct the relative hypogonadotropic hypogonadism of obesity, thereby providing a potential treatment strategy to mitigate some of the adverse effects of high BMI on fertility, assisted reproduction, and pregnancy outcomes.

CLINICAL TRIAL REGISTRATION NUMBER

ClinicalTrials.gov #NCT02478775.

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.

Chlormadinone acetate in progestin-primed ovarian stimulation does not negatively affect clinical results

Purpose

To investigate whether progestin-primed ovarian stimulation (PPOS) with chlormadinone acetate (CMA) adversely affects clinical results and neonatal outcomes, or causes congenital deformities.

Methods

This retrospective study was conducted at private IVF clinic from November 2018 to November 2021. Women underwent oocyte retrieval using gonadotropin-releasing hormone (GnRH) antagonist protocol (n = 835) or PPOS protocol (n = 57) were included. Eligible patients were normal ovarian responders (aged <40, AMH ≧1.0 ng/mL) with freeze-all cycle. Embryo developments, clinical results, or neonatal outcomes of singletons derived from transfer of frozen single blastocysts were compared within each group.

Results

Patient characteristics were similar in both groups. The median LH level (mIU/mL) at trigger in the GnRH antagonist group [2.0 (1.2-3.7)] was significantly higher than in the PPOS group [0.9 (0.3-1.7)]. There was no cycle with premature LH surge in the PPOS group. Fertilization and blastocyst formation rates did not differ significantly between groups. Furthermore, clinical outcomes were also similar in the two groups. Congenital abnormality rates did not differ significantly [0.9% (3/329), 0.0% (0/17)].

Conclusions

CMA using ovarian stimulation did not negatively affect clinical results. Our data suggest that PPOS with CMA is an appropriate ovarian stimulation method for normal ovarian responders.

A novel orally active gonadotropin-releasing hormone antagonist, relugolix, is a potential substitute for injectable GnRH antagonists in controlled ovarian stimulation in assisted reproductive technology

Purpose

To evaluate the efficacy of an oral gonadotropin‐releasing hormone antagonist (GnRH Ant), relugolix (R), for assisted reproductive technology (ART).

Methods

We enrolled women undergoing ART using a GnRH Ant for controlled ovarian stimulation. We compared R; 20 mg/day with cetrorelix acetate (C); 0.125 mg. C was administered to 88 women in 2019, and R to 93 women in 2020. Clinical outcomes associated with ART were assessed in both groups.

Results

The luteinizing hormone levels on the day of human chorionic gonadotropin injection in the R group (1.26 ± 0.93 IU/L) were significantly lower than those in the C group (2.85 ± 3.02 IU/L). There were no cases in which egg retrieval was canceled in both groups. The total doses of gonadotropins administered were greater in the R group compared with the C group. The number of days of GnRH Ant administration in the R group (1.71 ± 0.57 days) was significantly longer compared with the C group (1.48 ± 0.58 days). The number of oocytes collected, fertilization rates, and pregnancy rates (R; 47.1% vs C; 45.8%) did not differ between the two groups.

Conclusion

An orally active GnRH Ant, relugolix, when used in controlled ovarian stimulation for ART, showed comparable clinical outcomes with cetrorelix.

Therapeutic effects of an oral gonadotropin-releasing hormone receptor antagonist, relugolix, on preventing premature ovulation in mild ovarian stimulation for IVF

Purpose

Can relugolix, a novel oral gonadotropin-releasing hormone receptor (GnRH) antagonist, function as an alternative ovulation inhibitor to GnRH antagonist injections?

Methods

This single-center, cross-sectional retrospective study compared premature ovulation rates and clinical outcomes in IVF treatment after mild ovarian stimulation with 40 mg of relugolix (relugolix group) or 0.25-mg injections of ganirelix acetate or cetrorelix acetate (injection group) between March 2019 and January 2020. Of 247 infertile women (256 IVF cycles) aged ≤42 years, 223 women (230 cycles) were evaluated. In the relugolix and injection groups, we compared 104 and 85 cycles after GnRH antagonist use before the LH surge (LH levels <10 mIU/ml) and 22 and 19 cycles during the LH surge (LH levels ≥10 mIU/ml), respectively.

Results

Before the LH surge, the ovulation rates in the two groups were very low (p = 0.838), however; during the LH surge, the cycles using relugolix had a high ovulation rate of 40.9% compared with no ovulation in the injection group (p = 0.002). There were no significant differences in embryo culture findings and pregnancy outcomes between the two groups.

Conclusions

Although relugolix had a high ovulation suppressive effect, when the LH surge occurred, its effect was insufficient.

Magnetic solid-phase extraction of high molecular weight peptides using stearic acid-functionalized magnetic hydroxyapatite nanocomposite: determination of some hypothalamic agents in biological samples

Therapeutic peptides have an important effect on physiological function and human health, so it is momentous to quantify and detect low levels of these biomolecules in biological samples for treatment and diagnostic purposes. In the present study, an efficient magnetic solid-phase extraction (MSPE) method was developed based on stearic acid-functionalized magnetic hydroxyapatite nanocomposite (MHAP/SA) as a novel and cost-effective adsorbent for extraction of five hypothalamic-related peptides (goserelin, octreotide, triptorelin, somatostatin, and cetrorelix) from biological samples. To characterize the morphology and physicochemical properties of MHAP/SA, Fourier transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDS), field emission scanning microscopy (FE-SEM), CHNS elemental analysis, Brunauer-Emmett-Teller (BET), and vibrating sample magnetometry (VSM) were applied. Under optimum conditions, the proposed method (MSPE-HPLC-UV) represented favorable linearity with R² ≥ 0.9987, suitable intra- and inter-day precisions (RSD ≤ 6.9% and RSD ≤ 8.1%, respectively, n = 3), and limits of detection and quantification in the range of 0.75-1.12 ng mL^-1 and 2.50-3.75 ng mL^-1, respectively. Eventually, the proposed method was used for the extraction and quantification of target therapeutic peptides in plasma and urine samples, and satisfactory relative recoveries were achieved in the range of 90.6-110.3%.

[Effects of cetrorelix versus ganirelix in gonadotropin-releasing hormone antagonist cycles for preventing premature luteinizing hormone surges and on clinical outcomes of IVF-ET cycles]

OBJECTIVE

To compare the effects of cetrorelix and ganirelix in gonadotropin-releasing hormone antagonist (GnRH-ant) cycles for preventing premature luteinizing hormone (LH) surges and on clinical outcomes of IVF-ET cycles.

METHODS

We retrospectively analyzed 2572 GnRH-ant cycles of in vitro fertilization and embryo transfer from January, 2013 to December, 2016, including 1368 cycles with cetrorelix treatment and 1204 cycles with ganirelix treatment. The baseline characteristics of the patients and the clinical outcomes of the two groups were compared.

RESULTS

Compared with those receiving ganirelix treatment, the patients with cetrorelix treatment had a significantly younger age (33.10 vs 33.89 years, P < 0.001) and a lower body mass index (21.57 vs 21.84 kg/m², P=0.024). After adjustment for age and body mass index of the patients, no significant differences were found between the two groups in the levels of follicle-stimulating hormone (FSH), LH, estradiol (E₂), progesterone (P) levels either at the baseline or on the day of hCG triggering, or in the number of oocytes retrieved (P > 0.05). The two groups also had comparable percentages of patients with LH > 10 U/L on the day of hCG triggering (3.7% vs 3.2%) and similar spontaneous ovulation rate (0.6% vs 0.5%), clinical pregnancy rate (47.7% vs 45.9%) and live birth rate (37.5% vs 33.6%) following fresh embryo transfer (P > 0.05). The incidence of moderate to severe ovarian hyperstimulation syndrome, however, was significantly higher in ganirelix group than in cetrorelix group (0.7% vs 0.1%, P=0.006).

CONCLUSIONS

Cetrorelix and ganirelix can achieve comparable effects for preventing premature LH surges and can achieve similar clinical outcomes of GnRH-ant cycles, but ganirelix is associated with a significantly higher incidence of moderate to severe ovarian hyperstimulation syndrome.

Progestin vs. Gonadotropin-Releasing Hormone Antagonist for the Prevention of Premature Luteinizing Hormone Surges in Poor Responders Undergoing in vitro Fertilization Treatment: A Randomized Controlled Trial

Objective: Progestin was recently used as an alternative of gonadotropin-releasing hormone (GnRH) analog for preventing premature luteinizing hormone (LH) surge with the aid of vitrification techniques, however, limited data were available about the potential of progestin in poor responders undergoing in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) treatment. We performed a randomized parallel controlled trial to investigate the difference of progestin and GnRH antagonist in poor responders. Methods: A total of 340 poor responders who met with Bologna criteria were randomly allocated into the progestin-primed ovarian stimulation (PPOS) group and GnRH antagonist group. Fresh embryo transfer was preferred in the GnRH antagonist group and freeze-all was performed in the PPOS group. The primary outcome was the incidence of premature LH surge, secondary outcomes were the number of retrieved oocytes, the number of viable embryos and the pregnancy outcomes. Results: The results showed that the incidence of premature LH surge in PPOS group was lower than that in antagonist group (0 vs. 5.88%, P < 0.05). In PPOS group, the average numbers of oocytes and viable embryos were comparable to those in GnRH antagonist group (3.7 ± 2.6 vs. 3.4 ± 2.4; 1.6 ± 1.7 vs. 1.4 ± 1.3, P > 0.05), the live birth rate was similar between the two groups (21.8 vs. 18.2%, RR 1.25 (95% confidence interval 0.73, 2.13), P > 0.05). Conclusions: The study demonstrated that PPOS had a more robust control for preventing premature LH rise than GnRH antagonist in poor responders, but PPOS in combination with freeze-all did not significantly increase the probability of pregnancy than GnRH antagonist protocol for poor responders.

Anovulatory Patients Demonstrate a Sharp Decline in LH Levels upon GnRH Antagonist Administration during IVF Cycles

To evaluate the decrease in luteinizing hormone (LH) levels following gonadotropin-releasing hormone (GnRH) antagonist administration in in vitro fertilization (IVF) cycles, data were retrospectively collected from 305 consecutive IVF or intracytoplasmic sperm injection (ICSI) cycles of patients who underwent ovarian stimulation with gonadotropins and were treated with GnRH antagonist for the prevention of premature luteinization. We compared the percent change in LH concentration from stimulation start to that observed before ovulation triggering in patients with or without anovulation. Anovulatory patients were younger, with higher body mass index (BMI), and demonstrated higher ovarian reserve parameters as compared to ovulatory patients. The decline in LH concentration was almost two-fold greater in anovulatory versus ovulatory patients. Numbers of oocytes, fertilizations, cleavage stage embryos, and transferred embryos were similar; however, implantation rates were higher in anovulatory versus ovulatory patients. Older patients (age ≥39) showed a smaller decline in LH levels as compared to younger ones (age <39) and exhibited poor IVF outcomes. There is a wide range of pituitary responses to GnRH antagonists. Anovulatory patients are more susceptible to GnRH antagonists and therefore demonstrate over-suppression of the pituitary. Older patients demonstrate a reduced pituitary response to GnRH antagonists than younger ones. Cycle scheduling with estradiol pretreatment did not influence LH decline, nor IVF treatment outcomes.

Early gonadotropin-releasing hormone antagonist start improves follicular synchronization and pregnancy outcome as compared to the conventional antagonist protocol

OBJECTIVE

To assess whether an early GnRH antagonist start leads to better follicular synchronization and an improved clinical pregnancy rate (CPR).

METHODS

A retrospective cohort study. A total of 218 infertile women who underwent IVF between January 2011 and February 2013. The initial cohort (Cohort I) that underwent IVF between January 2011 and March 2012 included a total of 68 attempted IVF cycles. Thirty-four cycles were treated with the conventional GnRH antagonist protocol, and 34 cycles with an early GnRH antagonist start protocol. The second cohort (Cohort II) that underwent IVF between June 2012 and February 2013 included a total of 150 embryo-transfer (ET) cycles. Forty-three cycles were treated with the conventional GnRH antagonist protocol, 34 cycles with the modified early GnRH antagonist start protocol using highly purified human menopause gonadotropin and an addition of GnRH agonist to the luteal phase support, and 73 cycles with the GnRH agonist long protocol.

RESULTS

The analysis of Cohort I showed that the number of mature oocytes retrieved was significantly higher in the early GnRH antagonist start cycles than in the conventional antagonist cycles (11.9 vs. 8.2, p=0.04). The analysis of Cohort II revealed higher but non-significant CPR/ET in the modified early GnRH antagonist start cycles (41.2%) than in the conventional antagonist cycles (30.2%), which was comparable to that of the GnRH agonist long protocol cycles (39.7%).

CONCLUSION

The modified early antagonist start protocol may improve the mature oocyte yield, possibly via enhanced follicular synchronization, while resulting in superior CPR as compared to the conventional antagonist protocol, which needs to be studied further in prospective randomized controlled trials.

Evidence of GnRH antagonist escape in obese women

CONTEXT

Assisted reproductive technology (ART) cycle cancelation rates are increased among overweight and obese women; however, the reasons for this are not completely clear. Premature luteinization due to inadequate endogenous gonadotropin suppression is a possibility for this higher risk of cancellation.

OBJECTIVE

The objective of the study was to investigate the impact of female obesity on the pharmacokinetics of cetrorelix (GnRH antagonist).

DESIGN

This was an interventional study.

SETTING

The study was conducted at a university clinical and translational research center.

PARTICIPANTS

Regularly menstruating obese (n = 10) and normal-weight (n = 10) women participated in the study.

INTERVENTIONS

A frequent blood sampling study was performed after a GnRH antagonist was administered, followed by recombinant LH.

MAIN OUTCOMES MEASURED

Pharmacokinetics of cetrorelix in obese vs normal weight women were measured.

RESULTS

Five of the obese women (50%) and none of the normal-weight women had a rebound of LH (defined as >50% increase in LH level from nadir) over the 14-hour postdose observation period. The obese group had a significantly decreased distributional half-life of cetrorelix compared with the normal-weight group (8.1 ± 1.6 vs 12.7 ± 6.2 hours, P = .02). The obese group exhibited increased clearance of cetrorelix compared with the normal-weight group (25.8 ± 6.8 vs 20.1 ± 8.3 L/h, P = .058).

CONCLUSIONS

The altered pharmacokinetics of cetrorelix in obese women may lead to premature ovulation during ART, and this could be one of the mechanisms that results in increased cycle cancelation in this group of women. In accordance with the higher gonadotropin requirements for obese women undergoing ART, weight-based dosing of GnRH antagonists may be required.

Effects of cetrorelix, a GnRH-receptor antagonist, on gonadal axis in women with functional hypothalamic amenorrhea

BACKGROUND

Gonadotropin Releasing Hormone (GnRH) antagonists (GnRHa) suppress gonadotropin and sex-steroid secretion. In normal women, acute GnRHa administration induces inhibitory effect on pituitary-gonadal axis, followed by Luteinizing Hormone (LH) rebound. Functional hypothalamic amenorrhea (HA) is characterised by impaired gonadotropin secretion and hypogonadism secondary to blunted GnRH pulsatility.

METHODS

We studied the effects of a GnRHa, cetrorelix (CTX 3.0 mg), in six women with HA (age 30.7 ± 3.2 years; BMI 21.5 ± 1.7 kg/m(2)) and six control subjects (CS, 28.2 ± 0.6 years; 22.6 ± 0.9 kg/m(2)) on LH, Follicle-Stimulating Hormone (FSH) and oestradiol levels over 4 h (08.00-12.00 am) before, +24 h and +96 h after CTX; LH, FSH, and oestradiol were also evaluated at +6, +8, +12, +48, +72 h after CTX.

RESULTS

CS: CTX reduced (p < 0.05) LH, FSH, and oestradiol (nadir at +12 h, +24 h, and +24 h); LH rebounded at +96 h, FSH and oestradiol recovered at +48 h and +72 h. The 4-h evaluation showed LH and FSH reduction (p < 0.05) at +24 h, with LH rebound at +96 h. HA: CTX reduced (p < 0.05) LH, FSH, and oestradiol, (nadir at +24 h, +48 h, and +48 h, recovery at +48 h, +72 h, and +96 h). The 4-h evaluation showed gonadotropin reduction (p < 0.05) 24 h after CTX, without any rebound effect.

CONCLUSIONS

One single CTX dose still modulates gonadotropin secretion in HA. Its 'paradoxical' stimulatory effect on gonadotropins needs to be verified after prolonged administration.

Acute sex hormone suppression reduces skeletal muscle sympathetic nerve activity

OBJECTIVES

Comparisons of sympathetic nervous system activity (SNA) between young and older women have produced equivocal results, in part due to inadequate control for potential differences in sex hormone concentrations, age, and body composition. The aim of the present study was to determine the effect of a short-term reduction in sex hormones on tonic skeletal muscle sympathetic nerve activity (MSNA), an indirect measure of whole body SNA, using an experimental model of sex hormone deficiency in young women. We also assessed the independent effects of estradiol and progesterone add-back therapy on MSNA.

METHODS

MSNA was measured in 9 women (30±2 years; mean±SE) on three separate occasions: during the mid-luteal menstrual cycle phase, on the fifth day of gonadotropin-releasing hormone antagonist (GnRHant) administration, and after 5 days add-back of either estradiol (n=4) or progesterone (n=3) during continued GnRHant administration.

RESULTS

In response to GnRHant, there were significant reductions in serum estradiol and progesterone (both p<0.01) and MSNA (25.0±1.9 vs. 19.2±2.4 bursts/min, p=0.04). Continued GnRHant plus add-back estradiol or progesterone resulted in a nonsignificant decrease (19.2±1.7 vs. 12.1±1.9 bursts/min, p=0.07) or increase (16.2±1.7 vs. 21.0±6.0 bursts/min, p=0.39), respectively, in MSNA when compared with GnRHant alone.

INTERPRETATION

The findings of this preliminary study suggest that short-term ovarian hormone suppression attenuates MSNA and that this may be related to the suppression of progesterone rather than estradiol.

Effect of GnRH analogues on apoptosis and expression of Bcl-2, Bax, Fas and FasL proteins in endometrial epithelial cell cultures from patients with endometriosis and controls

BACKGROUND

Our purpose was to evaluate the effect of the GnRH agonist (GnRHa), leuprolide acetate (LA), and the GnRH antagonist (GnRHant), Antide, on apoptosis and expression of apoptosis-related proteins in endometrial epithelial cell (EEC) cultures from patients with endometriosis and controls (infertile women without endometriosis).

METHODS

Biopsy specimens of eutopic endometrium were obtained from 22 patients with endometriosis and from 14 women that served as controls. Apoptosis was examined in EEC after incubation with LA and Antide. Bax, Bcl-2, Fas and FasL expression was evaluated after exposure to LA, Antide or a combination of both. The percentage of apoptotic cells (%ApC) was assessed by the acridine orange-ethidium bromide technique, and protein expression was evaluated by western blot and immunocytochemistry.

RESULTS

LA 100 and 1000 ng/ml increased the %ApC in EEC from patients with endometriosis (both P < 0.05) and controls (p < 0.05 and P < 0.01, respectively). Antide 10(-5) M increased the %ApC in EEC from patients with endometriosis and controls (P < 0.01). In EEC from women with endometriosis, Bax expression increased after treatment with LA, Antide and LA + Antide (P < 0.05, P < 0.001 and P < 0.001), whereas Bcl-2 expression decreased after exposure to LA and Antide (P < 0.001 and P < 0.01). FasL expression increased after LA, Antide and LA + Antide treatments (P < 0.01, P < 0.001 and P < 0.01). No significant changes were observed on Fas expression.

CONCLUSIONS

GnRH analogues enhanced apoptosis in EEC, and this was accompanied by an increase in expression of the pro-apoptotic proteins Bax and FasL and a decrease in expression of the anti-apoptotic protein Bcl-2.

Hormonal manipulations in the luteal phase to coordinate subsequent antral follicle growth during ovarian stimulation

During the early follicular phase in the menstrual cycle, antral follicle sizes are often markedly heterogeneous. These follicular size discrepancies may, at least in part, result from the early exposure of FSH-sensitive follicles to gradient FSH concentrations during the preceding luteal phase. In addition, they potentially affect the results of ovarian stimulation. Indeed, pre-existing follicle size discrepancies may encumber coordinated follicular growth during ovarian stimulation, thereby reducing the number of follicles that reach maturation at once. To investigate this issue, three clinical studies were conducted to test the hypothesis that luteal FSH suppression could coordinate follicular growth. First, luteal FSH concentrations were artificially lowered by administering physiological oestradiol doses and measured follicular characteristics on the subsequent day 3. Second, it was verified whether luteal oestradiol administration could promote the coordination of follicular growth during ovarian stimulation and improve its results. Third, the effects of premenstrual gonadotrophin-releasing hormone (GnRH) antagonist administration on follicular characteristics were assessed during the early follicular phase. The results showed that luteal FSH suppression by either oestradiol or GnRH antagonist administration reduces the size and improves the homogeneity of early antral follicles during the early follicular phase, an effect that persists during ovarian stimulation. Coordination of follicular development may optimize ovarian response to short GnRH agonist and antagonist protocols, and constitutes an attractive approach to improving their outcome.

GnRH-antagonists in reproductive medicine

Suppression of sex steroid production based on desensitisation and down-regulation of pituitary gonadotropin-releasing hormone (GnRH)-receptors by agonistic GnRH-analogues resulting in the blockage of gonadotropin release from the anterior pituitary gland is a well-established approach in a variety of clinical conditions. Antagonistic analogues of GnRH exert their effect by competing with endogenous GnRH for pituitary binding sites. Because of the lack of any intrinsic activity of these compounds, the characteristic initial 'flare-up' effect of GnRH-agonist administration is absent. A more rapid suppression of gonadotropin release from the pituitary gland can be achieved, enabling shorter treatment regimes in ovarian hyperstimulation for assisted reproduction. As yet, GnRH-antagonists have attained market approval only for the indication of premature luteinizing hormone (LH) surge prevention in controlled ovarian hyperstimulation and palliative treatment of advanced prostatic cancer. However, GnRH-antagonists may be useful in a variety of other malignant and non-malignant indications where rapid sex steroid suppression is desired, such as uterine leiomyomas, endometriosis, gynaecological cancers or benign prostatic hyperplasia. In the context of infertility treatment, available data on the application of GnRH-antagonists in the treatment of endometriosis and uterine leiomyomas are reviewed.

Sex hormone suppression reduces resting energy expenditure and {beta}-adrenergic support of resting energy expenditure

Resting energy expenditure (REE) decreases with aging and may decrease in women as a result of the menopause, potentially contributing to weight gain. REE has been observed to fluctuate during the menstrual cycle, suggesting regulation by sex hormones. The aim of the present study was to determine the effects of suppressing estrogen and progesterone on REE. Fourteen premenopausal women, 29 +/- 5 yr old (mean +/- sd), were studied in the midluteal menstrual phase (ML) and after 6 d of GnRH antagonist therapy (GnRHant) administered in the follicular menstrual phase. REE was measured by indirect calorimetry in the morning after a 12-h fast and again during beta-adrenergic blockade to determine sympathetic nervous system (SNS) support of REE. Treatment with GnRHant significantly decreased REE (1405 +/- 42 vs. 1334 +/- 36 kcal/d, mean +/- se, ML vs. GnRHant; P = 0.002). Additionally, SNS blockade tended to alter REE more during ML than during GnRHant (-19 +/- 10 vs. 5 +/- 11 kcal/d; P = 0.14). Suppression of sex hormones to postmenopausal levels by GnRHant reduced REE in young healthy women. These findings suggest that the withdrawal of estrogen and/or progesterone attenuates REE, possibly through a SNS-mediated mechanism.

Premenstrual administration of gonadotropin-releasing hormone antagonist coordinates early antral follicle sizes and sets up the basis for an innovative concept of controlled ovarian hyperstimulation

OBJECTIVE

To investigate whether premenstrual administration of a GnRH antagonist coordinates early antral follicle sizes during the subsequent follicular phase.

DESIGN

Prospective, longitudinal study.

SETTING

University Hospital in France

PATIENT(S)

Twenty-five women, 50 cycles.

INTERVENTION(S)

On cycle day 2 (control/day 2), women underwent measurements of early antral follicles by ultrasound and serum FSH and ovarian hormones. On day 25, they received a single cetrorelix acetate administration, 3 mg. On the subsequent day 2 (premenstrual GnRH antagonist/day 2), participants were re-evaluated as on control/day 2.

MAIN OUTCOME MEASURE(S)

Magnitude of follicular size discrepancies.

RESULT(S)

Follicular diameters (4.1 +/- 0.9 vs. 5.5 +/- 1.0 mm) and follicle-to-follicle size differences decreased on premenstrual GnRH antagonist/day 2 as compared with control/day 2. Consistently, FSH (4.5 +/- 1.9 vs. 6.7 +/- 2.4 mIU/mL), E(2) (23 +/- 13 vs. 46 +/- 26 pg/mL), and inhibin B (52 +/- 30 vs. 76 +/- 33 pg/mL) were lower on GnRH antagonist/day 2 than on control/day 2.

CONCLUSION(S)

Premenstrual GnRH antagonist administration reduces diameters and size disparities of early antral follicles on day 2, likely through the prevention of luteal FSH elevation and early follicular development. This simple, original approach may be used to coordinate multifollicular development in controlled ovarian hyperstimulation.

Gonadotropin-Releasing Hormone Antagonists for Assisted Reproductive Techniques

Gonadotropin-releasing hormone (GnRH) antagonists have been tested extensively in ovarian stimulation protocols for assisted reproductive techniques (ART). GnRH antagonists immediately and rapidly inhibit gonadotropin release by the anterior pituitary gland by competitive blockage of the GnRH receptor, preventing and interrupting luteinising hormone surges in controlled ovarian hyperstimulation for infertility treatment. A review of the available literature on GnRH antagonists for ART is presented, focusing on the pharmacological and clinical properties of the two compounds available on the market, cetrorelix and ganirelix. Both cetrorelix and ganirelix are well tolerated and effective drugs for controlled ovarian hyperstimulation and are of comparable value for infertility treatment. Cetrorelix is available as a 0.25mg preparation for daily injections and as a 3mg intermediate depot preparation. Ganirelix is available as a 0.25mg preparation for daily injections.Currently, two treatment protocols are used in clinical practice: the GnRH antagonist multiple-dose protocol and the GnRH antagonist single-dose protocol. Both protocols are effective and well tolerated. Cetrorelix and ganirelix have not yet been directly compared in a clinical trial; nor have the single-dose and the multiple-dose approaches been compared in a randomised, controlled trial. Data to compare these compounds in clinical terms can be extrapolated only from results of phase II dose-finding studies and phase III studies comparing GnRH agonist cycles with GnRH antagonists in single- and multiple-dose protocols. Therefore, all conclusions on clinical differences between cetrorelix and ganirelix should remain tentative, as they are based on a limited amount of available data.Randomised, controlled trials comparing cetrorelix and ganirelix are warranted to further evaluate benefits and drawbacks of individual GnRH antagonists. Furthermore, more data are needed to determine the efficacy and safety of cetrorelix and ganirelix in established treatment protocols in patients other than those included in clinical trials investigating new drugs, such as "poor responders", patients with polycystic ovaries, patients with a history of allergy or overweight patients.

Suppression and recovery of LH secretion by a potent and selective GnRH-receptor antagonist peptide in healthy early follicular-phase women are mediated via selective control of LH secretory burst mass

AIM

GnRH antagonists are competitive inhibitors of GnRH receptors. Their administration induces prompt suppression of the gonadal axis. In animals, GnRH antagonists upregulate the activity of GnRH-secreting neurones, which could cause gonadotrophin rebound following inhibition. The aim of this study was to evaluate the effects of a potent GnRH antagonist, Teverelix (TEV), on the gonadal axis in healthy young women.

SUBJECTS AND MEASUREMENTS

In nine women [20-35 years old, body mass index (BMI) 19-25 kg/m2] in the early follicular phase, serum LH and FSH levels were evaluated every 10 min from 08.00 to 12.00 h before, and 24 h and 96 h after TEV injection (2.5 mg in 1 ml subcutaneously on day 0). Serum gonadotrophin and oestradiol levels were also evaluated at baseline and at 6, 8, 12, 48, 72 h after TEV.

RESULTS

The antagonist reduced both serum LH and FSH concentrations; LH levels were significantly and promptly reduced at +6 h (nadir at +8 h) until +48 h and recovered at +72 h, while FSH levels were reduced (P<0.05) 24 h after the antagonist and normalized at +48 h. LH (but not FSH) concentrations at +96 h exceeded baseline (P<0.05). TEV suppressed oestradiol concentrations (P<0.05) with a nadir at +24 h, comparable reduction at +48 h and recovery to baseline at +72 h. Deconvolution analysis showed that the antagonist peptide suppressed (P<0.02) the pulsatile production rate, burst mass and amplitude of LH on day 1. Pulsatile FSH secretion also fell at this time (P<0.05). LH and FSH pulse frequency were not modified by TEV. At +96 h, LH pulsatility did not significantly differ from that at baseline. Suppression of mean LH or FSH concentrations did not affect the relative pattern regularity (approximate entropy) of LH and FSH secretion.

CONCLUSIONS

This study demonstrates that the acute administration of a potent GnRH antagonist induces prompt inhibition of the gonadal axis lasting for 2 days in women due to mechanistically specific suppression of LH secretory burst mass and the mean FSH secretion rate. The trend toward rebound release of LH following the end of the pharmacological effect of the antagonist could reflect a rise in endogenous GnRH activity.

No influence of body weight on pregnancy rate in patients treated with cetrorelix according to the single- and multiple-dose protocols

The question of whether adjustment to body weight is necessary in in-vitro fertilization (IVF) cycles using GnRH antagonists is currently under discussion. Therefore, a data analysis of five prospective studies using either the single- or the multiple-dose antagonist protocol with cetrorelix (Cetrotide) was performed. The influence of stimulation procedure, gonadotrophins and body weight on pregnancy rate was evaluated in a linear logit model. The effect of the stimulation procedure and body weight on the cumulus-oocyte complex (COC) and follicle number was explored in an ANOVA model. Cetrorelix plasma concentrations were tested for any correlation with body weight. Baseline and outcome parameters in different body weight groups (<50 kg, 50-59 kg, 60-69 kg, 70-79 kg, > or =80 kg) were assessed for human menopausal gonadotrophin and recombinant human FSH stimulation separately. Cetrorelix plasma concentrations were correlated with body weight, but no influence of the type of stimulation or body weight on pregnancy rate was found. Body weight did not influence cetrorelix plasma concentrations. In contrast, body weight significantly influenced the number of retrieved COC as well as the number of follicles on the day of human chorionic gonadotrophin administration. Body weight does not influence the outcome of treatment in cetrorelix cycles.

Pharmacokinetic/pharmacodynamic modeling of luteinizing hormone (LH) suppression and LH surge delay by cetrorelix after single and multiple doses in healthy premenopausal women

Cetrorelix (CET) is a potent luteinizing hormone-releasing hormone (LH-RH) antagonist and is used to prevent premature ovulation in IVF (in vitro fertilization) procedures. The objective of the present study was to develop a pharmacokinetic/pharmacodynamic (PK/PD) model for the LH suppression and LH surge delay after single doses (SD) and multiple doses (MD) of CET in healthy premenopausal women without ovarian stimulation. CET was given by subcutaneous route (SD, 0.25, 0.5, or 1 mg) on cycle day 3 and as similar multiple once-a-day doses from cycle day 3 to day 16 in two consecutive menstrual cycles. The concentration-time data of CET and LH were used for PK/PD modeling. A two-compartment model described the PK of CET with median terminal half-life estimates of 9.2 and 54.5 hours after SD and MD, respectively. An indirect-response Emax model was used to describe the LH suppression and the LH surge delay. LH suppression was linked to plasma concentrations of CET, while the delay in the LH surge was linked to the PK of CET through a hypothetical effect compartment. Since the SD regimen on day 3 did not cause significant delay, these values were used as controls in the analysis of surge delay in MD data. The IC50 (for suppression) estimate was 0.73 ng/ml for SD, and EC50 (surge delay) was 1.42 ng/ml for MD. The PK/PD model adequately described the LH suppression and the surge delay.

Gonadotropin-releasing-hormone-receptor antagonists

Pulsatile gonadotropin-releasing hormone (GnRH) stimulates the pituitary secretion of both luteinising hormone (LH) and follicle-stimulating hormone (FSH) and thus controls the hormonal and reproductive function of the gonads. Blockade of GnRH effects may be wanted for a variety of reasons-eg, to prevent untimely luteinisation during assisted reproduction or in the treatment of sex-hormone-dependent disorders. Selective blockade of LH/FSH secretion and subsequent chemical castration have previously been achieved by desensitising the pituitary to continuously administered GnRH or by giving long-acting GnRH agonists. Only recently have GnRH-receptor antagonists, that immediately block GnRH's effects, been developed for clinical use with acceptable pharmacokinetic, safety, and commercial profiles. In assisted reproduction, these compounds seem to be as effective as established therapy but with shorter treatment times, less use of gonadotropic hormones, improved patient acceptance, and fewer follicles and oocytes. All current indications for GnRH-agonist desensitisation may prove to be indications for a GnRH antagonist, including endometriosis, leiomyoma, and breast cancer in women, benign prostatic hypertrophy and prostatic carcinoma in men, and central precocious puberty in children. However, the best clinical evidence so far has been in assisted reproduction and prostate cancer.

Use of third generation gonadotropin-releasing hormone antagonists in in vitro fertilization-embryo transfer: a review

Before gonadotropin-releasing hormone agonists (GnRHa) became available, approximately 20% of stimulated cycles within an in vitro fertilization (IVF) program were cancelled due to premature LH surges. By using the GnRHa to prevent LH surges via gonadotrope GnRH receptor down-regulation and desensitization, this percentage decreased to about 2%, and concomitantly, the IVF and pregnancy rates per cycle initiated were increased. Several treatment schedules currently are in use, including the so-called "long protocol," in which the GnRHa is begun in the luteal phase and down-regulation occurs before the start of the gonadotropin-stimulation treatment phase. This is generally the most effective regimen and is presently the most frequently used protocol. However, it has some disadvantages, such as hypoestrogenic side effects and an increase in the number of ampules of FSH or hMG required for adequate stimulation. There is a new generation of GnRH antagonists now clinically available, that has been able to minimize the potential side effects and provide reliable antagonism at the GnRH receptor. These agents seem better suited than GnRHa for assisted reproductive technology (ART) cycles inasmuch as they can prevent LH surges without requiring complete gonadotropin suppression. We have reviewed the current literature concerning their use in IVF cycles.