A randomised study of GnRH antagonist (cetrorelix) versus agonist (busereline) for controlled ovarian stimulation: effect on safety and efficacy

Live birth rate of gonadotropin-releasing hormone antagonist versus luteal phase gonadotropin-releasing hormone agonist protocol in IVF/ICSI: a systematic review and meta-analysis

In vitro fertilization (IVF) and embryo transfer and intracytoplasmic sperm injection (ICSI) have allowed millions of infertile couples to achieve pregnancy. As an essential part of IVF/ICSI enabling the retrieval of a high number of oocytes in one cycle, controlled ovarian stimulation (COS) treatment mainly composes of the standard long gonadotrophin-releasing hormone agonist (GnRH-a) protocol and the gonadotrophin-releasing hormone antagonist (GnRH-ant) protocol. However, the effectiveness of GnRH-ant protocol is still debated because of inconsistent conclusions and insufficient subgroup analyses. This systematic review and meta-analysis included a total of 52 studies, encompassing 5193 participants in the GnRH-ant group and 4757 in the GnRH-a group. The findings of this study revealed that the GnRH-ant protocol is comparable with the long GnRH-a protocol when considering live birth as the primary outcome, and it is a favourable protocol with evidence reducing the incidence of ovarian hyperstimulation syndrome in women undergoing IVF/ICSI, especially in women with polycystic ovary syndrome. Further research is needed to compare the subsequent cumulative live birth rate between the two protocols among the general and poor ovarian response patients since those patients have a lower clinical pregnancy rate, fewer oocytes retrieved or fewer high-grade embryos in the GnRH-ant protocol.

Risk factors for low oocyte retrieval in patients with polycystic ovarian syndrome undergoing in vitro fertilization

BACKGROUND

The number of oocytes retrieved does not always coincide with the number of follicles aspirated in in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) treatment. Patients with high expectation of retrieval sometimes obtain few oocytes, which may be induced by improper operation or therapeutic factors. The purpose of this study was to evaluate the distribution data of oocyte retrieval rate (ORR) and to explore the risk factors for low ORR in patients with polycystic ovary syndrome (PCOS) undergoing IVF/ICSI.

METHODS

A total of 2478 patients with PCOS undergoing IVF/ICSI were involved in this retrospective case-control study from March 2016 to October 2021. The oocyte retrieval rate was calculated as the ratio of the number of obtained oocytes to the number of follicles (≥ 12 mm) on the trigger day. Patients were divided into a low ORR and a normal ORR group with the boundary of one standard deviation from the mean value of ORR. The patient characteristics, treatment protocols, serum hormone levels, and embryonic and pregnancy outcomes were analyzed.

RESULTS

The ORR exhibited a non-normal distribution, with a median of 0.818. The incidence of complete empty follicle syndrome was 0.12% (3/2478). The proportion of patients in the low ORR group who received the progestin-primed protocol was significantly higher than that in the normal ORR group (30.30% vs. 17.69%). A logistic regression analysis showed that the serum estradiol level/follicle (≥ 12 mm) ratio (OR: 0.600 (0.545-0.661)) and progesterone level (OR: 0.783 (0.720-0.853)) on the trigger day were significant factors in the development of a low ORR, with optimal cutoff values of 172.85 pg/ml and 0.83 ng/ml, respectively, as determined by receiver operating curve. Fewer high-quality embryos (2 vs. 5) and more cycles with no available embryos (5.42% vs. 0.43%) were found in the low ORR group.

CONCLUSIONS

For patients with PCOS, low estradiol levels/follicles (≥ 12 mm) and progesterone levels on the trigger day and the use of the progestin-primed protocol could be risk factors for low ORR, which leads to a limited number of embryos and more cycle cancellations.

What is the optimal GnRH antagonist protocol for ovarian stimulation during ART treatment? A systematic review and network meta-analysis

BACKGROUND

Several GnRH antagonist protocols are currently used during COS in the context of ART treatments; however, questions remain regarding whether these protocols are comparable in terms of efficacy and safety.

OBJECTIVE AND RATIONALE

A systematic review followed by a pairwise and network meta-analyses were performed. The systematic review and pairwise meta-analysis of direct comparative data according to the PRISMA guidelines evaluated the effectiveness of different GnRH antagonist protocols (fixed Day 5/6 versus flexible, ganirelix versus cetrorelix, with or without hormonal pretreatment) on the probability of live birth and ongoing pregnancy after COS during ART treatment. A frequentist network meta-analysis combining direct and indirect comparisons (using the long GnRH agonist protocol as the comparator) was also performed to enhance the precision of the estimates.

SEARCH METHODS

The systematic literature search was performed using Embase (Ovid), MEDLINE (Ovid), Cochrane Central Register of Trials (CENTRAL), SCOPUS and Web of Science (WOS), from inception until 23 November 2021. The search terms comprised three different MeSH terms that should be present in the identified studies: GnRH antagonist; assisted reproduction treatment; randomized controlled trial (RCT). Only studies published in English were included.

OUTCOMES

The search strategy resulted in 6738 individual publications, of which 102 were included in the systematic review (corresponding to 75 unique studies) and 73 were included in the meta-analysis. Most studies were of low quality. One study compared a flexible protocol with a fixed Day 5 protocol and the remaining RCTs with a fixed Day 6 protocol. There was a lack of data regarding live birth when comparing the flexible and fixed GnRH antagonist protocols or cetrorelix and ganirelix. No significant difference in live birth rate was observed between the different pretreatment regimens versus no pretreatment or between the different pretreatment protocols. A flexible GnRH antagonist protocol resulted in a significantly lower OPR compared with a fixed Day 5/6 protocol (relative risk (RR) 0.76, 95% CI 0.62 to 0.94, I2 = 0%; 6 RCTs; n = 907 participants; low certainty evidence). There were insufficient data for a comparison of cetrorelix and ganirelix for OPR. OCP pretreatment was associated with a lower OPR compared with no pretreatment intervention (RR 0.79, 95% CI 0.69 to 0.92; I2 = 0%; 5 RCTs, n = 1318 participants; low certainty evidence). Furthermore, in the network meta-analysis, a fixed protocol with OCP resulted in a significantly lower OPR than a fixed protocol with no pretreatment (RR 0.84, 95% CI 0.71 to 0.99; moderate quality evidence). The surface under the cumulative ranking (SUCRA) scores suggested that the fixed protocol with no pretreatment is the antagonist protocol most likely (84%) to result in the highest OPR. There was insufficient evidence of a difference between fixed/flexible or OCP pretreatment/no pretreatment interventions regarding other outcomes, such as ovarian hyperstimulation syndrome and miscarriage rates.

WIDER IMPLICATIONS

Available evidence, mostly of low quality and certainty, suggests that different antagonist protocols should not be considered as equivalent for clinical decision-making. More trials are required to assess the comparative effectiveness of ganirelix versus cetrorelix, the effect of different pretreatment interventions (e.g. progestins or oestradiol) or the effect of different criteria for initiation of the antagonist in the flexible protocol. Furthermore, more studies are required examining the optimal GnRH antagonist protocol in women with high or low response to ovarian stimulation.

Identification and structural elucidation of a new cetrorelix methylene dimer impurity in cetrorelix acetate by using LC-MS/MS

Cetrorelix, a potent third generation of luteinizing hormone releasing hormone (LHRH) antagonist, is a synthetic decapeptide used for treatment of infertility, prostatic hypertrophy and sexual hormone-dependent tumors. The approved drug of cetrorelix (Cetrotide, Asta Medica AG, Frankfurt, Germany.), was used for prevention of premature ovulation in patients undergoing a controlled ovarian stimulation (COS), followed by oocyte pick-up and assisted reproductive techniques, and has been shown safe and effective in controlled ovarian stimulation. Nevertheless, the study of aggregation products of cetrorelix was rarely reported. A simple liquid chromatography mass spectrometry (LC-MS/MS) method was developed for separation, identification and characterization of a new cetrorelix methylene dimer impurity in cetrorelix. The chromatographic separation was achieved on an XSelect Peptide CSH ™C₁₈ column (150 × 4.6 mm, 3.5 μm particle size) using gradient elution with a mobile phase of ammonium formate buffer (pH 3.0, 20 mM), acetonitrile at a flow rate 1.0 mL min^-1, and an ultraviolet detection wavelength of 226 nm. The new cetrorelix methylene dimer impurity was characterized by LC-MS/MS and it characteristic fragment ions were summarized. A simple, fast and accurate method was established for the determination of the molecular weight and structure of the new cetrorelix methylene dimer impurity. In this study, the results showed that the cetrorelix was highly unstable in formaldehyde conditions. In addition, it is proposed that the impact of formaldehyde in the environment on the quality of cetrorelix acetate for Injection should be evaluated during the production process.

Effect of GnRH analogues for pituitary suppression on oocyte morphology in repeated ovarian stimulation cycles

OBJECTIVE

To compare the effect of pituitary suppression regimens on oocyte morphology in consecutive ICSI cycles of the same patients.

METHODS

Data was obtained from 200 matched consecutive intracytoplasmic sperm injection (ICSI) cycles performed in 100 couples undergoing the first cycle with the GnRH agonist and the following cycle with the GnRH antagonist regimen, from January 2010 to August 2016, in a private university-affiliated IVF centre. The effects of the pituitary suppression type on oocyte morphology were assessed by multivariate General Linear Models.

RESULTS

Mean interval between cycles was 185.32±192.85 days. Maternal age, body mass index, and total FSH dose administered were similar in both patients' cycles. Antagonist cycles presented lower incidence of dark cytoplasm (0.69±3.28% vs. 4.40±17.70%, p=0.047), Smooth endoplasmic reticulum (SER cluster (4.37±11.62% vs. 7.36±17.17%, p=0.046), and ZP defects (6.05±14.76% vs. 11.84±25.13%, p=0.049). Similar numbers of follicles retrieved oocytes, and mature oocytes were observed between the GnRH groups, as well as the fertilisation rate, number of obtained embryos, high-quality embryo rates, and the clinical outcomes.

CONCLUSION

GnRH antagonist's inhibitory effect on the ovaries in consecutive ICSI cycles results in improved oocyte maturity and morphology, despite similar laboratory and clinical outcomes, compared to the GnRH agonist treatment.

GnRH antagonist versus long agonist protocols in IVF: a systematic review and meta-analysis accounting for patient type

BACKGROUND

Most reviews of IVF ovarian stimulation protocols have insufficiently accounted for various patient populations, such as ovulatory women, women with polycystic ovary syndrome (PCOS) or women with poor ovarian response, and have included studies in which the agonist or antagonist was not the only variable between the compared study arms.

OBJECTIVE AND RATIONALE

The aim of the current study was to compare GnRH antagonist protocols versus standard long agonist protocols in couples undergoing IVF or ICSI, while accounting for various patient populations and treatment schedules.

SEARCH METHODS

The Cochrane Menstrual Disorders and Subfertility Review Group specialized register of controlled trials and Pubmed and Embase databases were searched from inception until June 2016. Eligible trials were those that compared GnRH antagonist protocols and standard long GnRH agonist protocols in couples undergoing IVF or ICSI. The primary outcome was ongoing pregnancy rate. Secondary outcomes were: live birth rate, clinical pregnancy rate, number of oocytes retrieved and safety with regard to ovarian hyperstimulation syndrome (OHSS). Separate comparisons were performed for the general IVF population, women with PCOS and women with poor ovarian response. Pre-planned subgroup analyses were performed for various antagonist treatment schedules.

OUTCOMES

We included 50 studies. Of these, 34 studies reported on general IVF patients, 10 studies reported on PCOS patients and 6 studies reported on poor responders. In general IVF patients, ongoing pregnancy rate was significantly lower in the antagonist group compared with the agonist group (RR 0.89, 95% CI 0.82-0.96). In women with PCOS and in women with poor ovarian response, there was no evidence of a difference in ongoing pregnancy between the antagonist and agonist groups (RR 0.97, 95% CI 0.84-1.11 and RR 0.87, 95% CI 0.65-1.17, respectively). Subgroup analyses for various antagonist treatment schedules compared to the long protocol GnRH agonist showed a significantly lower ongoing pregnancy rate when the oral hormonal programming pill (OHP) pretreatment was combined with a flexible protocol (RR 0.74, 95% CI 0.59-0.91) while without OHP, the RR was 0.84, 95% CI 0.71-1.0. Subgroup analysis for the fixed antagonist schedule demonstrated no evidence of a significant difference with or without OHP (RR 0.94, 95% CI 0.79-1.12 and RR 0.94, 95% CI 0.83-1.05, respectively). Antagonists resulted in significantly lower OHSS rates both in the general IVF patients and in women with PCOS (RR 0.63, 95% CI 0.50-0.81 and RR 0.53, 95% CI 0.30-0.95, respectively). No data on OHSS was available from trials in poor responders.

WIDER IMPLICATIONS

In a general IVF population, GnRH antagonists are associated with lower ongoing pregnancy rates when compared to long protocol agonists, but also with lower OHSS rates. Within this population, antagonist treatment prevents one case of OHSS in 40 patients but results in one less ongoing pregnancy out of every 28 women treated. Thus standard use of the long GnRH agonist treatment is perhaps still the approach of choice for prevention of premature luteinization. In couples with PCOS and poor responders, GnRH antagonists do not seem to compromise ongoing pregnancy rates and are associated with less OHSS and therefore could be considered as standard treatment.

Comparisons of GnRH antagonist protocol versus GnRH agonist long protocol in patients with normal ovarian reserve: A systematic review and meta-analysis

OBJECTIVE

To evaluate the effectiveness and safety of gonadotropin-releasing hormone antagonist (GnRH-ant) protocol and gonadotropin-releasing hormone agonist (GnRH-a) long protocol in patients with normal ovarian reserve.

METHODS

We searched the PubMed (1992-2016), Cochrane Library (1999-2016), Web of Science (1950-2016), Chinese Biomedical Database (CBM, 1979-2016), and China National Knowledge Infrastructure (CNKI, 1994-2016). Any randomized controlled trials (RCTs) that compared GnRH-ant protocol and GnRH-a long protocol in patients with normal ovarian reserve were included, and data were extracted independently by two reviewers. The meta-analysis was performed by Revman 5.3 software.

RESULTS

Twenty-nine RCTs (6399 patients) were included in this meta-analysis. Stimulation days (mean difference (MD) [95% confidence interval (CI)] = -0.8 [-1.36, -0.23], P = 0.006), gonadotrophin (Gn) dosage (MD [95% CI] = -3.52 [-5.56, -1.48], P = 0.0007), estradiol (E2) level on the day of human chorionic gonadotrophin (HCG) administration (MD [95% CI] = -365.49 [-532.93, -198.05], P<0.0001), the number of oocytes retrieved (MD [95% CI] = -1.41 [-1.84, -0.99], P<0.00001), the embryos obtained (MD [95% CI] = -0.99 [-1.38, -0.59], P<0.00001), incidence of ovarian hyperstimulation syndrome (OHSS) (OR [95% CI] = 0.69 [0.57, 0.83], P<0.0001) were statistically significantly lower in GnRH-ant protocol than GnRH-a long protocol. However, the clinical pregnancy rate (OR [95% CI] = 0.90 [0.80, 1.01], P = 0.08), ongoing pregnancy rate (OR [95% CI] = 0.88 [0.77, 1.00], P = 0.05), live birth rate (OR [95% CI] = 0.95 [0.74, 1.09], P = 0.27), miscarriage rate (OR [95% CI] = 0.98 [0.69, 1.40], P = 0.93), and cycle cancellation rate (OR [95% CI] = 0.86 [0.52, 1.44], P = 0.57) showed no significant differences between the two groups.

CONCLUSION

GnRH-ant protocol substantially decreased the incidence of OHSS without influencing the pregnancy rate and live birth rate compared to GnRH-a long protocol among patients with normal ovarian reserve.

Gonadotrophin-releasing hormone antagonists for assisted reproductive technology

BACKGROUND

Gonadotrophin-releasing hormone (GnRH) antagonists can be used to prevent a luteinizing hormone (LH) surge during controlled ovarian hyperstimulation (COH) without the hypo-oestrogenic side-effects, flare-up, or long down-regulation period associated with agonists. The antagonists directly and rapidly inhibit gonadotrophin release within several hours through competitive binding to pituitary GnRH receptors. This property allows their use at any time during the follicular phase. Several different regimens have been described including multiple-dose fixed (0.25 mg daily from day six to seven of stimulation), multiple-dose flexible (0.25 mg daily when leading follicle is 14 to 15 mm), and single-dose (single administration of 3 mg on day 7 to 8 of stimulation) protocols, with or without the addition of an oral contraceptive pill. Further, women receiving antagonists have been shown to have a lower incidence of ovarian hyperstimulation syndrome (OHSS). Assuming comparable clinical outcomes for the antagonist and agonist protocols, these benefits would justify a change from the standard long agonist protocol to antagonist regimens. This is an update of a Cochrane review first published in 2001, and previously updated in 2006 and 2011.

OBJECTIVES

To evaluate the effectiveness and safety of gonadotrophin-releasing hormone (GnRH) antagonists compared with the standard long protocol of GnRH agonists for controlled ovarian hyperstimulation in assisted conception cycles.

SEARCH METHODS

We searched the Cochrane Menstrual Disorders and Subfertility Group Trials Register (searched from inception to May 2015), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, inception to 28 April 2015), Ovid MEDLINE (1966 to 28 April 2015), EMBASE (1980 to 28 April 2015), PsycINFO (1806 to 28 April 2015), CINAHL (to 28 April 2015) and trial registers to 28 April 2015, and handsearched bibliographies of relevant publications and reviews, and abstracts of major scientific meetings, for example the European Society of Human Reproduction and Embryology (ESHRE) and American Society for Reproductive Medicine (ASRM). We contacted the authors of eligible studies for missing or unpublished data. The evidence is current to 28 April 2015.

SELECTION CRITERIA

Two review authors independently screened the relevant citations for randomised controlled trials (RCTs) comparing different GnRH agonist versus GnRH antagonist protocols in women undergoing in vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI).

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial eligibility and risk of bias, and extracted the data. The primary review outcomes were live birth and ovarian hyperstimulation syndrome (OHSS). Other adverse effects (miscarriage and cycle cancellation) were secondary outcomes. We combined data to calculate pooled odds ratios (ORs) and 95% confidence intervals (CIs). Statistical heterogeneity was assessed using the I(2) statistic. We assessed the overall quality of the evidence for each comparison using GRADE methods.

MAIN RESULTS

We included 73 RCTs, with 12,212 participants, comparing GnRH antagonist to long-course GnRH agonist protocols. The quality of the evidence was moderate: limitations were poor reporting of study methods.Live birthThere was no conclusive evidence of a difference in live birth rate between GnRH antagonist and long course GnRH agonist (OR 1.02, 95% CI 0.85 to 1.23; 12 RCTs, n = 2303, I(2)= 27%, moderate quality evidence). The evidence suggested that if the chance of live birth following GnRH agonist is assumed to be 29%, the chance following GnRH antagonist would be between 25% and 33%.OHSSGnRH antagonist was associated with lower incidence of any grade of OHSS than GnRH agonist (OR 0.61, 95% C 0.51 to 0.72; 36 RCTs, n = 7944, I(2) = 31%, moderate quality evidence). The evidence suggested that if the risk of OHSS following GnRH agonist is assumed to be 11%, the risk following GnRH antagonist would be between 6% and 9%.Other adverse effectsThere was no evidence of a difference in miscarriage rate per woman randomised between GnRH antagonist group and GnRH agonist group (OR 1.04, 95% CI 0.82 to 1.30; 33 RCTs, n = 7022, I(2) = 0%, moderate quality evidence).With respect to cycle cancellation, GnRH antagonist was associated with a lower incidence of cycle cancellation due to high risk of OHSS (OR 0.47, 95% CI 0.32 to 0.69; 19 RCTs, n = 4256, I(2) = 0%). However cycle cancellation due to poor ovarian response was higher in women who received GnRH antagonist than those who were treated with GnRH agonist (OR 1.32, 95% CI 1.06 to 1.65; 25 RCTs, n = 5230, I(2) = 68%; moderate quality evidence).

AUTHORS' CONCLUSIONS

There is moderate quality evidence that the use of GnRH antagonist compared with long-course GnRH agonist protocols is associated with a substantial reduction in OHSS without reducing the likelihood of achieving live birth.

Ovarian hyperstimulation syndrome: pathophysiology, staging, prediction and prevention

OBJECTIVE

To identify, appraise and summarize the current evidence regarding the pathophysiology, staging, prediction and prevention of ovarian hyperstimulation syndrome (OHSS).

METHODS

Two comprehensive systematic reviews were carried out: one examined methods of predicting either high ovarian response or OHSS and the other examined interventions aimed at reducing the occurrence of OHSS. Additionally, we describe the related pathophysiology and staging criteria.

RESULTS

Seven studies examining methods of predicting OHSS and eight more examining methods of predicting high ovarian response to controlled ovarian stimulation were included. Current evidence shows that the best methods of predicting high response are antral follicle count and anti-Müllerian hormone levels, and that a high ovarian response (examined by the number of large follicles, estradiol concentration or the number of retrieved oocytes) is the best method of predicting the occurrence of OHSS. Ninety-seven randomized controlled trials examining the effect of several interventions for reducing the occurrence of OHSS were included. There was high-quality evidence that replacing human chorionic gonadotropin by gonadotropin-releasing hormone agonists or recombinant luteinizing hormone, and moderate-quality evidence that antagonist protocols, dopamine agonists and mild stimulation, reduce the occurrence of OHSS. The evidence for the effect of the other interventions was of low/very low quality. Additionally, we identified and described 12 different staging criteria.

CONCLUSIONS

There are useful predictive tools and several preventive interventions aimed at reducing the occurrence of OHSS. Acknowledging and understanding them are of crucial importance for planning the treatment of, and, ultimately, eliminating, OHSS while maintaining high pregnancy rates.

Comparisons of GnRH antagonist versus GnRH agonist protocol in supposed normal ovarian responders undergoing IVF: a systematic review and meta-analysis

OBJECTIVE

To evaluate the effectiveness and safety of GnRH antagonist and GnRH agonist in supposed normal ovarian responders undergoing IVF.

METHODS

Data from 6 databases were retrieved for this study. The RCTs of GnRH agonist and GnRH antagonist use during IVF-EF therapy for patients with supposed normal ovarian response were included. A meta-analysis was performed with Revman 5.1software.

RESULTS

Twenty-three RCTs met the inclusion criteria. The number of stimulation days (mean difference (MD): -0.66, 95% confidence interval (CI): -1.04∼-0.27), Gn amount (MD: -2.92, 95% CI: -5.0∼-0.85), E2 values on the day of HCG (MD: -330.39, 95% CI: -510.51∼-150.26), Number of oocytes retrieved (MD: -1.33, 95% CI: -2.02∼-0.64), clinical pregnancy rate (odds ratio (OR): 0.87, 95% CI: 0.75-1.0), and ovarian hyperstimulation syndrome (OHSS) incidence (OR: 0.59, 95% CI: 0.42∼0.82) were significantly lower in GnRH antagonist protocol than GnRH agonist protocol. However, the endometrial thickness on the day of HCG (MD: -0.04, 95% CI: -0.23∼0.14), the ongoing pregnancy rate (OR: 0.87, 95% CI: 0.74∼1.03), live birth rate (OR: 0.89, 95% CI: 0.64∼1.24), miscarriage rate (OR: 1.17, 95% CI: 0.85∼1.61), and cycle cancellation rate (OR: 1.11, 95% CI: 0.90∼1.37) did not significantly differ between the 2 groups.

CONCLUSIONS

During IVF treatment for patients with supposed normal responses, the incidence of OHSS were significantly lower, whereas the ongoing pregnancy and live birth rates were similar in the GnRH antagonist compared with the standard long GnRH agonist protocols.

Optimal usage of the GnRH antagonists: a review of the literature

Gonadotropin-releasing hormone (GnRH) antagonists, which became commercially available from 1999, have been used for the prevention of premature luteinizing hormone (LH) surges in controlled ovarian stimulation for in vitro fertilization or intracytoplasmic sperm injection. This review focuses on the recent literature on the use of GnRH antagonists and provides guidelines for optimal use in light of increasing evidence showing that GnRH antagonists are safe and effective, allowing flexibility of treatment in a wide range of patient populations. This includes patients undergoing first-line controlled ovarian stimulation, poor responders, and women diagnosed with polycystic ovary syndrome. The GnRH antagonist offers a viable alternative to the long agonists, providing a shorter duration of treatment with fewer injections and with no adverse effects on assisted reproductive technology outcome. This results in a significantly lower amount of gonadotropins required, which is likely to lead to improved patient compliance.

Gonadotrophin-releasing hormone antagonists for assisted reproductive technology

BACKGROUND

Gonadotrophin-releasing hormone (GnRH) antagonists can be used to prevent a luteinizing hormone (LH) surge during controlled ovarian hyperstimulation (COH) without the hypo-estrogenic side-effects, flare-up, or long down-regulation period associated with agonists. The antagonists directly and rapidly inhibit gonadotropin release within several hours through competitive binding to pituitary GnRH receptors. This property allows their use at any time during the follicular phase. Several different regimes have been described including multiple-dose fixed (0.25 mg daily from day six to seven of stimulation), multiple-dose flexible (0.25 mg daily when leading follicle is 14 to 15 mm), and single-dose (single administration of 3 mg on day 7 to 8 of stimulation) protocols, with or without the addition of an oral contraceptive pill. Further, women receiving antagonists have been shown to have a lower incidence of ovarian hyperstimulation syndrome (OHSS). Assuming comparable clinical outcomes for the antagonist and agonist protocols, these benefits would justify a change from the standard long agonist protocol to antagonist regimens. This is an update of a Cochrane review first published in 2001, and previously updated in 2006.

OBJECTIVES

To evaluate the effectiveness and safety of gonadotrophin-releasing hormone (GnRH) antagonists with the standard long protocol of GnRH agonists for controlled ovarian hyperstimulation in assisted conception cycle

SEARCH STRATEGY

We performed electronic searches of major databases, for example Cochrane Menstrual Disorders and Subfertility Group Specialised Register, CENTRAL, MEDLINE, EMBASE (from 1987 to April 2010); and handsearched bibliographies of relevant publications and reviews, and abstracts of major scientific meetings, for example the European Society of Human Reproduction and Embryology (ESHRE) and American Society for Reproductive Medicine (ASRM). A date limited search of Cochrane Menstrual Disorders and Subfertility Group Specialised Register, CENTRAL from April 2010 to April 2011 was run. Eighteen studies have been entered into the Classification pending references section of this update. These studies will be appraised for inclusion or exclusion in the next update of this review, due April 2012.

SELECTION CRITERIA

Two review authors independently screened the relevant citations for randomised controlled trials (RCTs) comparing different agonist versus antagonist protocols in women undergoing IVF or ICSI.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial risk of bias and extracted data. If relevant data were missing or unclear, the authors were contacted for clarification.

MAIN RESULTS

Forty-five RCTs (n = 7511) comparing the antagonist to the long agonist protocols fulfilled the inclusion criteria. There was no evidence of a statistically significant difference in rates of live-births (9 RCTs; odds ratio (OR) 0.86, 95% CI 0.69 to 1.08) or ongoing pregnancy (28 RCTs; OR 0.87, 95% CI 0.77 to 1.00). There was a statistically significant lower incidence of OHSS in the GnRH antagonist group (29 RCTs; OR 0.43, 95% CI 0.33 to 0.57).

AUTHORS' CONCLUSIONS

The use of antagonist compared with long GnRH agonist protocols was associated with a large reduction in OHSS and there was no evidence of a difference in live-birth rates.

The relationship between endometrial thickness and pregnancy rates in GnRH antagonist down-regulated ICSI cycles

OBJECTIVE

To investigate the effects of endometrial thickness measurements and serum hormone levels on the outcomes of GnRH antagonist down-regulated ICSI cycles.

STUDY DESIGN

Forty consecutive infertile women undergoing controlled ovarian hyperstimulation with recombinant FSH and GnRH antagonists for ICSI were enrolled in this study. All patient's age, day 3 FSH, antral follicle count (AFC), serum E2 levels on day 3, E2 on stimulation day 5, E2 on day of hCG administration, endometrial thickness on the baseline (ETMBaseline), on day 5 of stimulation (ETMDay 5), on day of hCG administration (ETMhCG) and cycle outcomes were recorded. The outcomes of pregnant and nonpregnant women were compared.

RESULTS

Women's age was 33.6 +/- 4.9. Overall pregnancy rate was 45% (n = 18), clinical pregnancy rate was 27.5% (n = 11) and ongoing pregnancy rate was 20% (n = 8). In pregnant women, baseline AFC was significantly higher compared with nonpregnant women (p = 0.01). There was no significant correlation between ETMhCG and E2 level on the day of hCG, number of retrieved oocytes or patients' age.

CONCLUSION

For achieving pregnancy, endometrial thickness on the day of hCG is not a determining parameter, and the only significant determinent is AFC in GnRH antagonist down-regulated ICSI cycles.

GnRH antagonist, cetrorelix, for pituitary suppression in modern, patient-friendly assisted reproductive technology

BACKGROUND

Gonadotropin-releasing hormone (GnRH) analogues are used routinely to prevent a premature luteinizing hormone (LH) surge in women undergoing assisted reproductive technology (ART) treatments. In contrast to GnRH agonists, antagonists produce rapid and reversible suppression of LH with no initial flare effect.

OBJECTIVE

To review the role of cetrorelix, the first GnRH antagonist approved for the prevention of premature LH surges during controlled ovarian stimulation in modern ART.

METHOD

A review of published literature on cetrorelix.

RESULTS

Both multiple- and single-dose cetrorelix protocols were shown to be at least as effective as long GnRH agonist regimens for pituitary suppression in Phase II/III clinical trials. Furthermore, cetrorelix co-treatment resulted in similar live birth rates but a shorter duration of gonadotropin stimulation, a lower total gonadotropin dose requirement and lower incidence of ovarian hyperstimulation syndrome compared with long agonist regimens. A single-dose cetrorelix protocol further decreased the number of injections required. Preliminary studies have also produced promising data on the use of cetrorelix in modified ART protocols, such as frozen embryo transfer and donor oocyte recipient cycles.

CONCLUSION

Cetrorelix offers a potential therapeutic alternative to GnRH agonists during controlled ovarian stimulation and has become an integral part of modern, patient-friendly reproductive medicine.

Follicular growth and oocyte maturation in GnRH agonist and antagonist protocols for in vitro fertilisation and embryo transfer

BACKGROUND

The aim of this study was to evaluate the response to treatment in a group of patients undergoing IVF and randomised to receive GnRH-antagonist or the GnRH-agonist. The endpoints were the pattern of follicular growth, the maturity of the oocytes collected, the embryo quality and the pregnancy outcome.

METHODS

A total of 136 patients undergoing IVF were included. Sixty-seven patients were allocated to the GnRH antagonist and 69 patients to the GnRH agonist. GnRH antagonist was administered when the leading follicle reached a diameter of 12-14 mm. GnRH agonist was administered in a long luteal protocol.

RESULTS

The mean numbers of oocytes retrieved and mature oocytes were significantly higher in the agonist than in the antagonist group (p < 0.02 and p < 0.01, respectively). Embryo quality, implantation rate, clinical pregnancy rates, ongoing pregnancy rate and miscarriage rate were similar in both groups.

CONCLUSIONS

Better follicular growth and oocyte maturation are achieved with GnRH agonist treatment. However, both regimens seem to have similar efficacy in terms of implantation and pregnancy rates. Further studies clarifying the effect of the GnRH antagonist on ovarian function are needed, as well as a clear definition of the best period of the follicular phase for the GnRH antagonist administration.

Timing and duration of use of GnRH antagonist down-regulation for IVF/ICSI cycles have no impact on oocyte quality or pregnancy outcomes

PURPOSE

To evaluate whether oocyte quality, implantation and pregnancy outcomes in in vitro fertilization (IVF)/intra-cytoplasmic sperm injection (ICSI) are related to the duration of gonadotropin-releasing hormone (GnRH)-antagonist use or the timing of its initiation.

METHODS

Retrospective cohort study of 178 conventional IVF/ICSI cycles. All patients underwent ovarian stimulation with gonadotropins and GnRH-antagonist for pituitary down-regulation. Spearman correlations and logistic regression were used for statistical analysis.

RESULTS

There was no correlation between the duration of use or the timing of initiation of GnRH-antagonist with oocyte quality or implantation and pregnancy outcomes. Oocyte quality was influenced by the peak estradiol. Implantation was influenced by the patient's age. Early pregnancy loss, by the endometrial thickness on human chorionic gonadotropin-day. Ongoing pregnancy was independent from the variables evaluated.

CONCLUSIONS

GnRH-antagonist duration of use or starting day did not influence oocyte quality, implantation rates, and pregnancy rates. We hypothesize that a follicle stimulating hormone/luteinizing hormone dose increase when antagonist was started, may have had an impact on our findings.

Gonadotrophin-releasing hormone antagonists for assisted conception: a Cochrane review

Gonadotrophin-releasing hormone (GnRH) antagonists suppress gonadotrophin secretion resulting in dramatic reduction in treatment cycle duration. Assuming comparable clinical outcomes, these benefits may justify changing the standard long GnRH agonist protocol to GnRH antagonist regimens. To evaluate the evidence, databases (e.g. Cochrane Library, MEDLINE, EMBASE) were electronically searched, hand searches were performed, and manufacturers in the field were contacted. Twenty-seven randomized controlled trials (RCT) fulfilled inclusion criteria for comparison of GnRH antagonist with long GnRH agonist protocol. Clinical pregnancy rate and ongoing pregnancy/live-birth rate were significantly lower in the antagonist group (P = 0.009; OR = 0.83, 95% CI 0.72-0.95 and P = 0.02; OR = 0.82, 95% CI 0.68-0.97 respectively). Conversely, incidence of severe OHSS was significantly reduced with the antagonist protocol (P = 0.01; OR = 0.60, 95% CI 0.40-0.88), and interventions to prevent OHSS were administered more frequently in the agonist group (P = 0.03; OR = 0.43, 95% CI 0.20-0.92). Concluding, GnRH antagonist protocols are short, simple, with good clinical outcomes and significant reduction in severe OHSS incidence and gonadotrophin amount; however, the lower pregnancy rate compared with the GnRH agonist long protocol necessitates counselling subfertile couples before recommending change from GnRH agonist to antagonist.

Role of gonadotropin-releasing hormone antagonists in poor responders

OBJECTIVE

To evaluate the role of GnRH antagonists in poor-responder protocols.

DESIGN

Literature review.

CONCLUSION(S)

The optimum stimulation protocol for poor responders is unknown. Although many IVF programs currently use GnRH antagonists for poor responders, there have been only four prospective, randomized trials comparing GnRH antagonists to alternate protocols. None of these studies had sufficient power to evaluate a difference in pregnancy rates (PRs), and in all four cases, IVF outcomes were comparable. Nevertheless, interest in the use of GnRH antagonists in poor responders has continued. GnRH antagonists may be associated with simpler stimulation protocols, lower gonadotropin requirements, reduced patient costs, and shorter downtimes between consecutive cycles. However, the greatest advantage of GnRH antagonists may lie in the ability to assess ovarian reserves immediately prior to deciding whether or not to initiate gonadotropin stimulation. The ability to respond to cycle-to-cycle variation in antral follicle counts may allow the optimization of oocyte yield and reduce cycle cancellation rates. It remains to be seen if this approach (initiating gonadotropins only in cycles where an adequate antral follicle count is present) also translates into higher clinical PRs for poor responders.

In vivo characterization of a novel GnRH (gonadotropin-releasing hormone) antagonist, LXT-101, in normal male rats

LXT-101 is a newly developed GnRH (gonadotropin-releasing hormone) analogue. In this study, the in vivo pharmacological profile in intact male rats and binding characters of LXT-101 were illustrated, and regulation of mRNA of hormone receptors related to the pituitary-gonadal axis during and after administration was observed to reveal its molecular mechanism of potent effect and reversibility. After single subcutaneous injections, LXT-101 produced a dose- and time-dependent suppression of serum testosterone level. Multiple administrations and osmotic pump implantation revealed that the time of onset and dose needed to maintain the effect of chemical castration decreased as the frequency of injection increased and gave direct proof that depot formulation could significantly improve the duration of antagonist delivery and pharmacological activities compared to the injectable formulation. And LXT-101 showed excellent character of regulating the pituitary-gonadal axis quickly and reversibly. Competitive binding assay showed that LXT-101 could specifically bind a pituitary GnRH receptor with high affinity. These results indicated that LXT-101 is fit for sustained-release formulation and it might possibly be developed as an ideal candidate for treating sex hormone-sensitive tumors and other disorders.

Among patients treated for IVF with gonadotrophins and GnRH analogues, is the probability of live birth dependent on the type of analogue used? A systematic review and meta-analysis

This systematic review and meta-analysis aimed to answer the following clinical question: among patients treated for IVF with gonadotrophins and GnRH analogues, is the probability of live birth per randomized patient dependent on the type of analogue used? Eligible studies were randomized controlled trials (RCTs), published as a full manuscript in a peer-reviewed journal, that contained sufficient information to allow ascertainment of whether randomization was true and whether equality was present between the groups compared. A literature search identified 22 RCTs comparing GnRH antagonists and GnRH agonists that involved 3176 subjects. Where live birth was not reported in a study that fulfilled the inclusion criteria, an effort was made to contact the corresponding authors to retrieve the missing information. If this was not possible, the reported outcome measure, clinical pregnancy or ongoing pregnancy was converted to live birth in 12 studies using published data (Arce et al., 2005). No significant difference was present in the probability of live birth between the two GnRH analogues [odds ratio (OR), 0.86; 95% confidence intervals (CI), 0.72 to 1.02]. This result remains stable in subgroup analysis that ordered the studies by type of population studied, gonadotrophin type used for stimulation, type of agonist protocol used, type of agonist used, type of antagonist protocol used, type of antagonist used, presence of allocation concealment, presence of co-intervention and the way the information on live birth was retrieved. In conclusion, the probability of live birth after ovarian stimulation for IVF does not depend on the type of analogue used for pituitary suppression.

Gonadotrophin-releasing hormone antagonists for assisted conception

BACKGROUND

Gonadotrophin-releasing hormone antagonists produce immediate suppression of gonadotrophin secretion, hence, they can be given after starting gonadotrophin administration. This has resulted in dramatic reduction in the duration of treatment cycle. Two different regimes have been described. The multiple-dose protocol involves the administration of 0.25 mg cetrorelix (or ganirelix) daily from day six to seven of stimulation, or when the leading follicle is 14 to15 mm, until human chorionic gonadotrophin (HCG) administration and the single-dose protocol involves the single administration of 3 mg cetrorelix on day seven to eight of stimulation. Assuming comparable clinical outcome, these benefits would justify a change from the standard long protocol of GnRH agonists to the new GnRH antagonist regimens.

OBJECTIVES

To evaluate the evidence regarding the efficacy of gonadotrophin-releasing hormone (GnRH) antagonists with the standard long protocol of GnRH agonists for controlled ovarian hyperstimulation in assisted conception.

SEARCH STRATEGY

We searched Cochrane Menstrual Disorders and Subfertility Group's Specialised Register, MEDLINE and EMBASE databases from 1987 to February 2006, and handsearched bibliographies of relevant publications and reviews, and abstracts of scientific meetings. We also contacted manufacturers in the field.

SELECTION CRITERIA

Randomized controlled studies comparing different protocols of GnRH antagonists with GnRH agonists in assisted conception cycles were included in this review.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. If relevant data were missing or unclear, the authors have been consulted

MAIN RESULTS

Twenty seven RCTs comparing the GnRH antagonist to the long protocol of GnRH agonist fulfilled the inclusion criteria. Clinical pregnancy rate was significantly lower in the antagonist group. (OR = 0.84, 95% CI = 0.72 - 0.97). The ongoing pregnancy/ live-birth rate showed the same significant lower pregnancy in the antagonist group (P = 0.03; OR 0.82, 95% CI 0.69 to 0.98).However, there was statistically significant reduction in incidence of severe OHSS with antagonist protocol. The relative risk ratio was (P = 0.01; RR 0.61, 95% CI 0.42 to 0.89). In addition, interventions to prevent OHSS (e.g. coasting, cycle cancellation) were administered more frequently in the agonist group (P = 0.03; OR 0.44, 95% CI 0.21 to 0.93).

AUTHORS' CONCLUSIONS

GnRH antagonist protocol is a short and simple protocol with good clinical outcome with significant reduction in incidence of severe ovarian hyperstimulation syndrome and amount of gonadotrophins but the lower pregnancy rate compared to the GnRH agonist long protocol necessitates counseling subfertile couples before recommending change from GnRH agonist to antagonist..

Treatment of central precocious puberty

The problems of central precocious puberty (CPP) are serious enough to the patient to deserve treatment. There is a general consensus among paediatric endocrinologists that the treatment of true CPP (i.e., in children young enough to have a formal diagnosis) is indicated in many cases. In children with modestly early puberty who are not fulfilling the diagnostic criteria, this is not the case. The treatment of choice is a gonadotropin-releasing hormone (GnRH) analogue. Prolonged analogues are more effective than short-acting ones and, most importantly, independent of patient compliance. Data on agonists have accumulated over two decades and evidence of effects is rich in girls but sparse in boys. GnRH agonists are generally effective and safe drugs; the suppression of puberty is reversible and there is much information on GnRH agonists for the treatment of CPP showing very few adverse effects and the effects on final height are well documented in girls < 6 years of age. There is some (but not highly convincing) evidence for their effect on final height for those of 6 - 8 years of age and there is no evidence for an increase in final height after the age of 8 years in girls. If a decision to have treatment is taken, treatment should start immediately as a possible benefit is less probable if the start of treatment is delayed. When treatment should be stopped is a matter of controversy. Combination with growth hormone increases final height, but the clinical relevance can be discussed as well as the health economy aspects. The limits of indications are still to be defined.

Precycle administration of GnRH antagonist and microdose HCG decreases clinical pregnancy rates without affecting embryo quality and blastulation

The outcome of a novel protocol utilizing precycle gonadotrophin-releasing hormone (GnRH) antagonist administration and LH activity support with microdose recombinant human chorionic gonadotrophin (HCG) was compared to GnRH agonist long protocol used in patients undergoing their first ICSI (n=707) or IVF (n=571) cycles, which had resulted in one or two blastocyst transfers. In GnRH antagonist cycles, cetrorelix acetate (3 mg) was administered s.c. 4 days before FSH stimulation and a repeat dose was given when the lead follicular diameter was 13-14 mm. LH support was provided by recombinant HCG (2.5 microg). Embryo progression and blastulation were evaluated using embryo progression indices and blastocyst quality scores. The tested protocol demonstrated reduced implantation and clinical pregnancy rates as compared with GnRH agonist long protocol, although the embryo progression and blastulation parameters and blastocyst quality were comparable among the groups. Logistic regression models further supported the significant negative impact of GnRH antagonist/microdose HCG protocol on clinical pregnancy rates in both ICSI and IVF patients. Assisted reproduction cycles with fresh blastocyst transfers utilizing precycle GnRH antagonist administration and microdose HCG support resulted in lower implantation and clinical pregnancy rates as compared with GnRH agonist cycles, although the embryo progression and blastulation parameters were comparable.