Recombinant human luteinising hormone to mimic mid-cycle LH surge

Treatment of female infertility with recombinant human luteinising hormone: is there a benefit over other available drugs?

This manuscript reviews the role of recombinant human luteinising hormone (rhLH) as a therapeutic drug in ovarian stimulation for assisted reproductive technology (ART) and ovulation induction. For this purpose, the role of LH during the follicular phase and during the ovulatory surge, along with the role of human chorionic gonadotropin (hCG) as a surrogate LH, is reviewed and compared to the results available with the new rhLH formulation. The use of rhLH was found to be safe and highly effective given during the follicular phase and to mimic an endogenous LH surge. The availability of both LH and follicle stimulating hormone (FSH) as separate recombinant preparations enables physicians to adjust the doses of each gonadotropin to the individual patient according to the 'therapeutic window' concept for each drug to maximise the success of ovarian stimulation.

Development of gonadotrophins for clinical use

The 20th century witnessed the steady development of knowledge about reproductive physiology and endocrinology in animals and humans. These advances led to the identification of higher centres governing the ovary and its follicles. Effects of X-rays on the head and other agents, or excision of the pituitary gland, led to anomalies in oestrous and menstrual cycles in animals and women, respectively. Studies on pituitary and placental extracts revealed the presence of hormones regulating the ovarian follicles and the corpus luteum for the implanting embryo. These were identified as follicle stimulating hormone (FSH), luteinizing hormone (LH) and human chorionic gonadotrophin (HCG). Increasing understanding of the mechanisms of action of these hormones led to treatments of animals and amenorrhoeic women with FSH- and LH-containing preparations in order to induce the growth of follicles and ovulation. Human FSH-rich preparations were obtained by extracting urinary gonadotrophins from the urine of post-menopausal women, and thousands of amenorrhoeic and/or anovulatory patients were treated with human menopausal gonadotrophin (HMG) and HCG to induce multifolliculation and ovulation. The introduction of IVF greatly increased the numbers of women treated in this fashion, now including cyclic women. By the mid-1980s, following the appearance of Creutzfeld-Jakob disease in women treated with gonadotrophins extracted from human pituitaries, and other safety considerations, attempts were being made to purify urinary gonadotrophin preparations, using antibodies. Increasing interest in recombinant preparations, which were pure, highly specific and highly active preparations, characterized the last years of the 20th century and the new millennium. These preparations included recombinant FSH (rFSH), recombinant LH (rLH) and recombinant HCG (rHCG). Yet, in one sense, the recombinant preparations could change the procedures of ovarian stimulation, because they focused attention on the membranal receptor in the follicle, and how best to stimulate it. Small molecules are currently being investigated, with some proving to be very active and specific, and even capable of bypassing many parts of the receptor conformation. Here lies the immediate future of this field, utilizing small, defined molecules at low cost to stimulate follicle growth, ovulation and luteinization, and perhaps one day to remove the need for gonadotrophins in clinical work.

Achievement of pregnancy in globozoospermia with Y chromosome microdeletion after ICSI

Pregnancy achieved with sperm from a patient with globozoospermia is rare, even after ICSI, since the activation of the oocyte may not occur in this disorder. Therefore, activation of the oocytes by piezoelectricity or calcium ionophores has been suggested, although spontaneous activation of the oocyte after ICSI has been reported in some cases. We report a successful pregnancy in a couple in which the male partner had globozoospermia with microdeletions in the Y chromosome with no further assisted activation after ICSI. During the diagnostic study of the husband, increased numerical chromosome abnormalities after fluorescent in-situ hybridization (FISH) and microdeletions in AZFa; sY86 and AZFb; sY 131 were detected. Out of the 13 oocytes injected, four fertilized and a twin pregnancy was obtained after replacement of four embryos. Healthy twin girls were delivered after a term pregnancy. Some patients with globozoospermia may also have Y chromosome microdeletions, which subsequently may be inherited by the male offspring in cases of achievement of pregnancy.

Use of gonadotrophin-releasing hormone agonists to trigger ovulation

The introduction of gonadotrophin-releasing hormone (GnRH) agonists combined with gonadotrophins is considered to be one of the most significant advances in the development of in vitro fertilization (IVF) treatment. However, ovarian hyperstimulation syndrome (OHSS) remains a significant complication of controlled ovarian hyperstimulation. One possible strategy to reduce the risk of this complication would be the use of GnRH agonists instead of human chorionic gonadotrophin (hCG) to trigger the final stages of oocyte maturation. GnRH agonists are able to induce an endogenous surge of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) and the effect may be more physiological than that of exogenous hCG. Several uncontrolled and controlled clinical studies have confirmed the efficacy of GnRH agonists for triggering ovulation, and pregnancy rates are comparable to those achieved with hCG. The incidence of OHSS appears to be decreased, but larger controlled studies are required to confirm this observation. The recent introduction of GnRH antagonists has led to renewed interest in the use of GnRH agonists to induce final oocyte maturation. An international multicentre randomized controlled trial has been completed recently comparing the efficacy of GnRH agonist with hCG for triggering ovulation in women undergoing controlled ovarian hyperstimulation using the GnRH antagonist ganirelix for pituitary suppression. The aim of the study was to determine the efficacy of the novel protocol for ovarian stimulation before IVF, in terms of pregnancy outcomes and the prevention of OHSS.

Human recombinant luteinizing hormone is as effective as, but safer than, urinary human chorionic gonadotropin in inducing final follicular maturation and ovulation in in vitro fertilization procedures: results of a multicenter double-blind study

In a prospective, comparative, dose-finding study, the minimal effective dose of recombinant human LH (rhLH) required to induce final follicular maturation and early luteinization in patients undergoing in vitro fertilization and embryo transfer was determined. In addition, the efficacy and safety of rhLH were compared with urinary human CG (u-hCG). A total of 259 infertile women, aged 18-39 yr, were enrolled in the study. After pituitary desensitization using a GnRH agonist, rhFSH was administered for ovarian stimulation. Patients then received either rhLH or u-hCG to achieve final follicular maturation. The doses of rhLH administered were 5,000, 15,000, 30,000, or 15,000 + 10,000 IU (second injection administered 3 days after the first injection; 129 patients), and those of u-hCG were consistently 5,000 IU (121 patients). Ovum pick-up was performed 34--38 h after rhLH or u-hCG injection. After fertilization in vitro, up to three embryos were replaced in the uterine cavity. The numbers of oocytes retrieved after u-hCG or rhLH administration were not significantly different between the four different doses of rhLH, when compared with each corresponding u-hCG group, nor when compared with the pool of all u-hCG groups. Similarly, there were no statistically significant differences in: the number of oocytes retrieved per follicle with a diameter of over 10 mm on the day of u-hCG or rhLH administration; the number of patients with at least one oocyte retrieved; oocyte nuclear maturity; oocyte potential for fertilization; the number of embryos; the number of total, biochemical, and clinical pregnancies; and the embryo implantation rate. However, in many of these parameters, the lowest dose of rhLH seemed suboptimal when compared with the higher dose. In terms of safety, rhLH was well tolerated at a dose of up to 30,000 IU. Moderate ovarian hyperstimulation syndrome (OHSS) was reported in 12.4% of patients who received u-hCG and 12.0% of patients who received two injections of rhLH. No moderate or severe OHSS was reported in patients who received a single dose of rhLH up to 30,000 IU. The results show that a single dose of rhLH is effective in inducing final follicular maturation and early luteinization in in vitro fertilization and embryo transfer patients and is comparable with 5,000 IU u-hCG. A single dose of rhLH results in a highly significant reduction in OHSS compared with hCG. The dose of rhLH giving the highest efficacy to safety ratio was between 15,000 and 30,000 IU.

The role of gonadotropins in follicular development and their use in ovulation induction protocols for assisted reproduction

During the 1960s, hypogonadotropic patients with polycystic ovary syndrome and those with clomiphene citrate resistance were the first to achieve pregnancy after urinary human menopausal gonadotropin (hMG) administration plus preovulatory human chorionic gonadotropin injection, with cumulative pregnancy rates ranging from 40% to 80% after six to 12 treatment cycles. Ever since, dramatically more progress has been achieved regarding methods and medication in assisted conception techniques, involving both a rapidly increased number of subfertile couples, as well as many practitioners in obstetrics and gynecology. The purpose of this review was to highlight the most crucial historical steps of this remarkable process, by emphasizing the role of gonadotropins in ovulation induction protocols according to the various clinical categories of subfertile patients. In the late 1970s, urinary hMG was the most widely used gonadotropin for ovarian stimulation during in vitro fertilization-embryo transfer for assisted reproduction. The often concurrent problems of premature luteinizing hormone (LH) surges and premature luteinizations, and thus cancellations of the cycles, were efficiently overcome by 'reversible medical hypophysectomy', performed by gonadotropin releasing hormone (GnRH) analogs, introduced in 1982. According to its initiation and duration, GnRH analog use was divided into three protocols: the long, most widely used, protocol, which was the best for suppression of endogenous, high tonic LH levels, especially in polycystic ovary syndrome and normogonadotropic patients; and the short and ultra-short protocols, which were mainly used in poor responders to ovarian stimulation treatment, older or hypergonadotropic patients with ovarian failure, because of the well-known 'flare-up phenomenon'. Recently, GnRH antagonists, which directly do not permit GnRH action by binding to the GnRH gonadotropic cell receptors, have been used, but no final results from large, multicenter clinical trials that are still being undertaken have yet been achieved. Various sub-products of urinary hMG have been produced since the 1980s, with the intention of eliminating most or all of the LH, such as a form with a 3:1 proportion ratio between follicle stimulating hormone (FSH) and LH, as well as a form resulting in the removal of almost all of the LH, the 'pure' urinary FSH. Finally, in the mid-1990s, recombinant pure FSH was produced in vitro from hamster ovarian cell cultures. The theoretical basis for the broad use of pure urinary FSH and recombinant FSH is that the very low endogenous LH levels after pituitary desensitization are sufficient for proper theca steroidogenesis; still, data in the literature and clinical experience may be controversial upon that issue. From the clinical point of view, clinicians nowadays tend to stimulate polycystic ovary syndrome patients with recombinant FSH plus the application of GnRH analogs in a long protocol. However, in poor responders, patients in whom ovulation is resistant to clomiphene citrate, those older than 40 years or hypergonadotropic patients with ovarian failure, urinary hMG, because endogenous LH levels are obviously not sufficient for proper steroidogenesis in the theca cells of the follicles of these patients, is necessary in add to the administration of GnRH analogs in a short or ultra-short protocol. Regarding normogonadotropic women (the majority of patients), most authors agree with the long-protocol application of GnRH analogs. In these patients, it is not certain whether recombinant FSH alone is sufficient for the best possible induction or whether exogenous LH administration in the form of urinary hMG still remains necessary.

Role of LH and FSH in ovarian function

Human gonadotrophin preparations have been used in the treatment of infertility for almost four decades. The earliest preparations were derived from urine from postmenopausal women and contained approximately equal amounts of follicle stimulating hormone (FSH) and luteinizing hormone (LH) activities. However, with the recognition that FSH is the principal regulator of follicular growth and maturation, these have been largely superseded by highly purified urinary FSH preparations and, more recently, recombinant human FSH (r-hFSH). Because of its complexity, r-hFSH is expressed in mammalian cells grown in culture and, from a manufacturing stand point, offers superior purity and batch-to-batch consistency, compared with urinary preparations. A number of clinical trials have compared the efficacy of r-hFSH and urinary FSH in women undergoing assisted reproductive technologies (ART). In general, these have shown that fewer FSH ampoules are required to achieve ovarian stimulation with r-hFSH, while the number of oocytes retrieved and embryos produced are higher than with urinary FSH. Additionally, the results of a recent meta-analysis have also shown that the clinical pregnancy rate per cycle started is significantly higher with r-hFSH, compared with urinary FSH. Furthermore, in poor responder patients, higher implantation rates were seen in patients treated with r-hFSH than in those treated with urinary FSH, suggesting that embryo viability is increased following use of the recombinant preparations. The finding that FSH preparations produce effective ovarian stimulation compared to human menopausal gonadotrophins in women undergoing ART raises the question of whether LH is required for ovarian stimulation. This has been investigated in a number of recent studies. For example, results have suggested that implantation rates may actually be lower in women who received exogenous LH. Such studies suggest, therefore, that in normogonadotrophic women, the addition of LH to an r-hFSH regimen does not add any further clinical benefit and may actually be detrimental. Hence, it appears that LH administration is necessary only in women with hypogonadotrophic hypogonadism. In conclusion, r-hFSH is a consistently pure and high quality gonadotrophin preparation and contributes to increasing the successful outcome of an ART cycle. Together with careful auditing of routine clinical practice, and the application of evidence-based medicine to facilitate clinical decision making, this means that a total quality management approach can be applied to optimize the outcome of assisted reproduction.