Use of gonadotrophin releasing hormone (GnRH) antagonist (cetrotide) during ovarian stimulation for in-vitro fertilization treatment: multiple doses and single dose

A review of luteinising hormone and human chorionic gonadotropin when used in assisted reproductive technology

Gonadotropins extracted from the urine of post-menopausal women have traditionally been used to stimulate folliculogenesis in the treatment of infertility and in assisted reproductive technology (ART). Products, such as human menopausal gonadotropin (hMG), consist not only of a mixture of the hormones, follicle-stimulating hormone (FSH), luteinising hormone (LH) and human chorionic gonadotropin (hCG), but also other biologically active contaminants, such as growth factors, binding proteins and prion proteins. The actual amount of molecular LH in hMG preparations varies considerably due to the purification process, thus hCG, mimicking LH action, is added to standardise the product. However, unlike LH, hCG plays a different role during the natural human menstrual cycle. It is secreted by the embryo and placenta, and its main role is to support implantation and pregnancy. More recently, recombinant gonadotropins (r-hFSH and r-hLH) have become available for ART therapies. Recombinant LH contains only LH molecules. In the field of reproduction there has been controversy in recent years over whether r-hLH or hCG should be used for ART. This review examines the existing evidence for molecular and functional differences between LH and hCG and assesses the clinical implications of hCG-supplemented urinary therapy compared with recombinant therapies used for ART.

Endocrinological insights into different in vitro fertilization treatment aspects

The science of reproductive endocrinology/in vitro fertilization (IVF) has moved forward considerably since the first IVF baby was born in 1978. IVF was originally indicated for women with tubal factor infertility, but it has now become the treatment for couples with unexplained subfertility, male subfertility, cervical factor, failed ovulation induction, endometriosis or unilateral tubal pathology. IVF was initially performed with the single dominant ovarian follicle produced during a spontaneous menstrual cycle. This was very inefficient and pregnancy rates were dismal. Consequently, superovulation protocols using parenteral gonadotrophins to induce maturation of multiple follicles were soon adopted worldwide. In addition, any supernumerary embryos remaining after embryo transfer may be cryopreserved for future embryo transfers without the need for another fresh IVF cycle. A greater understanding of IVF endocrinology has led to improved IVF pregnancy outcomes and satisfaction for the anxious parents. However, with the greater success of IVF treatment, new complications associated with the treatment arise, namely the ovarian hyperstimulation syndrome. Ovarian hyperstimulation can be associated with severe morbidity and may be even fatal. Ovarian hyperstimulation syndrome is an iatrogenic condition secondary to medical stimulation of the ovary, and was virtually unknown until IVF treatment was initiated. This article will discuss the recent developments in IVF treatment endocrinology and protocols, as well as prevention/treatment of its complications.

New developments in the use of peptide gonadotropin-releasing hormone antagonists versus agonists

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 functions of the gonads. The blockade of the effects of GnRH may be sought for a variety of reasons; for example, to control premature LH surges and to reduce the cancellation rate with the aim of improving the pregnancy rate per treatment cycle 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. GnRH analogues are indicated for clinical situations in which the suppression of endogenous gonadotropins (precocious puberty, contraception and controlled ovarian hyperstimulation) or sexual steroids (endometriosis, prostate hyperplasia, cancer and uterine fibroids) is desired. The immediate suppression of the pituitary that is achieved by GnRH antagonists without an initial stimulatory effect is the main advantage of these compounds over the agonists. GnRH antagonists have 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 of the 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 has been in assisted reproduction and prostate cancer.

Ovarian response and follicular development for single-dose and multiple-dose protocols for gonadotropin-releasing hormone antagonist administration

OBJECTIVE

To determine the efficiency of a single-dose and a multiple-dose protocol for GnRH antagonist administration.

DESIGN

Randomized clinical trial.

SETTING

University hospital, tertiary medical center.

PATIENT(S)

Sixty-one patients undergoing controlled ovarian stimulation (COS) and IVF/ICSI.

INTERVENTION(S)

COS with either a multiple-dose (MD) or a single-dose (SD) protocol for GnRH antagonist (cetrorelix) administration, or with a long protocol (LP) for GnRH agonist (buserelin) administration, followed by oocyte retrieval, IVF/ICSI, and embryo transfer.

MAIN OUTCOME MEASURE(S)

Follicular development and serum levels of E2 and LH.

RESULT(S)

The SD protocol for cetrorelix was associated with a more reduced level of follicular development, lower levels of serum estradiol on the day of HCG administration, and a more reduced number of zygotes than the LP for buserelin. The pregnancy and implantation rates did not differ significantly for the three study groups.

CONCLUSION(S)

The MD and SD GnRH antagonist protocols were effective for preventing LH surge and appear to elicit an equivalent pregnancy rate to that corresponding to a LP GnRH agonist. In terms of follicular development, the SD protocol requires further modification, including flexible scheduling or possibly a small reduction of the dosage of the administered cetrorelix.

Clinical efficacy of the gonadotropin-releasing hormone antagonist, ganirelix, in Korean women undergoing controlled ovarian hyperstimulation for in vitro fertilization and embryo transfer with recombinant follicle-stimulating hormone

AIM

To assess the clinical efficacy and safety of the gonadotropin-releasing hormone (GnRH) antagonist, ganirelix (Orgalutran), treatment in women undergoing controlled ovarian hyperstimulation (COH) for in vitro fertilization and embryo transfer (IVF-ET) in Korean women.

METHODS

This was a non-comparative, open-label, single-center trial carried out on 31 infertile Korean women. A daily dose of 0.25 mg of the GnRH antagonist, ganirelix, was given, beginning on the sixth day of recombinant follicle-stimulating hormone (FSH) treatment. If the ovarian response was low, ganirelix treatment was delayed until the leading follicle reached a mean diameter of 14 mm. The ganirelix treatment was continued until the day of human chorionic gonadotropin (hCG) injection. Descriptive statistics were recorded for all parameters.

RESULTS

The median duration of ganirelix treatment was 4 days (range: 2-6 days) and the median total recombinant FSH dose was 1350 IU (900-2350 IU). During ganirelix treatment, the incidence of luteinizing hormone (LH) rises (LH = 10 IU/L) was 3.2% (one of 31 cases). On the day ovulation was triggered by hCG, the mean number of follicles >/=11 mm in diameter was 12.4 +/- 4.5, and the median of serum estradiol concentration was 4289.9 (1893.7-8268.5) pmol/L. The mean number of oocytes per retrieval was 10.9 +/- 6.1. The fertilization rate was 61.5%, and the mean number of replaced embryos was 2.8 +/- 0.6. The mean implantation rate was 10.0%, and the clinical pregnancy rate per transfer was 23.3% (seven of 30 cases) and the ongoing pregnancy rate per transfer was 20.0% (six of 30 cases).

CONCLUSION

The results of the present study support ganirelix as a safe, short, convenient and effective treatment for patients undergoing COH for IVF in Korean women.

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.

Safety and efficacy of a 3 mg dose of the GnRH antagonist cetrorelix in preventing premature LH surges: report of two large multicentre, multinational, phase IIIb clinical experiences

Gonadotrophin-releasing hormone antagonists are effective and safe in preventing premature LH surges, a leading cause of cycle cancellation or failure during assisted conception. Two studies assessed two administration regimens for cetrorelix (as Cetrotide): the multiple-dose (MD, 0.25 mg/day, n = 1066) and single-dose (SD, 3 mg, n = 541) protocols. Patient outcomes were very similar: >90% reached criteria for human chorionic gonadotrophin (HCG) administration and underwent oocyte retrieval; embryo transfer was performed in 83-84%; failure to retrieve oocytes was rare (0.8%); on average, 11 follicles > or =10 mm in diameter were seen on the day of HCG administration. The SD protocol was associated with higher numbers of oocytes retrieved and available for insemination, although the numbers of embryos obtained or transferred were comparable. A total of 251 and 121 pregnancies were reported in the MD and SD groups respectively. Pregnancy rates per embryo transfer were 27 and 28% respectively. Severe ovarian hyperstimulation syndrome (OHSS) occurred in <1% of cycles. Twelve per cent of patients reported local reactions to injections in the MD group, compared with 8% in the SD group; none was serious or led to discontinuation. Seventy-three per cent of patients in the SD group received only one injection. These two studies therefore show that the single-dose cetrorelix protocol offers equal efficacy and safety to the MD regimen, while having the advantage of requiring only one injection in most patients.

Depot GnRH agonist versus the single dose GnRH antagonist regimen (cetrorelix, 3 mg) in patients undergoing assisted reproduction treatment

The objective of this study was to compare, in a centre with previous experience of gonadotrophin-releasing hormone (GnRH) antagonist use, single administration of a GnRH antagonist [cetrorelix (Cetrotide) 3 mg] with a single administration of a GnRH agonist [Decapeptyl Retard 3.75 mg] in patients undergoing assisted reproduction treatment (n = 307 and 364 respectively). GnRH agonist was administered on the first day of menses, while cetrorelix was administered when the largest follicle reached 14 mm. Ovarian stimulation was performed with recombinant human FSH (r-hFSH; 150-225 IU/day). Human chorionic gonadotrophin (HCG, 10,000 IU) was administered when at least two follicles reached a mean diameter > or =18 mm. Over 90% of patients in both groups reached the criteria for HCG administration and underwent oocyte retrieval and embryo transfer. Duration of FSH therapy (9.95 versus 11.25 days) and cumulative dose of r-hFSH (1604 versus 1980 IU) were significantly reduced (P < 0.01) in the cetrorelix 3 mg group. The number of oocytes retrieved was lower (8.5 versus 11.2; P < 0.01) with cetrorelix, but the number of embryos replaced was similar (2.2 versus 2.3; NS). The pregnancy rates per oocyte retrieval were the same, 24.5%, in the antagonist and agonist groups. This study indicates that although fewer oocytes are recovered, similar pregnancy rates can be achieved with a GnRH antagonist compared with a GnRH agonist. Additionally, a single dose of 3 mg cetrorelix was administered in 84% of patients, thus being simpler and more convenient for patients. Cetrorelix 3 mg may thus be proposed as a first choice for preventing both a premature LH surge and detrimental rises in LH during ovarian stimulation prior to assisted reproduction treatment.

Comparable effectiveness using flexible single-dose GnRH antagonist (cetrorelix) and single-dose long GnRH agonist (goserelin) protocol for IVF cycles – a prospective, randomized study

This prospective randomized study compared the effectiveness of a flexible single-dose gonadotrophin-releasing hormone (GnRH) antagonist (cetrorelix) and a single-dose long GnRH agonist (goserelin) protocol for ovarian stimulation in IVF/intracytoplasmic sperm injection (ICSI) cycles. All patients from the waiting list were successively included in the study, pre-programmed with an oral contraceptive, and randomized into goserelin and cetrorelix groups. Depending on the date on which their menstrual period started, patients took oral contraceptives for one or two cycles. Ultimately, 236 patients in the first group received a single dose of depot preparation of goserelin and 224 patients received a single 3 mg dose of cetrorelix in the late follicular phase, when the mean follicle diameter exceeded 12 mm. The mean number of ampoules of FSH and the duration of stimulation was statistically significantly lower in the cetrorelix group than in the goserelin group (25.9 versus 34.5, and 9.6 versus 12.2 days, P < 0.01). The mean number of oocytes retrieved was similar (6.7 +/- 4.5 versus 7.2 +/- 4.6, NS). Similar results were observed in fertilization rates, blastulation rates and blastocyst transfer rates in both groups. Clinical pregnancy and delivery rates per cycle were higher in the goserelin group (34.3 and 30.1%) than in the cetrorelix group (31.9 and 28.3%), but the differences were not statistically significant. The flexible single-dose GnRH antagonist protocol is an advantageous alternative to the long GnRH agonist protocol, with similar efficacy, shorter duration, a significant reduction in the number of FSH ampoules used and without the menopause-like effects of the GnRH antagonist.