GnRH agonists and antagonists in assisted reproduction: pregnancy rate

Although gonadotrophin-releasing hormone (GnRH) antagonists offer many advantages when used in ovarian stimulation, their popularity is lower than expected. GnRH protocols are suspected to yield lower pregnancy rates compared with the long agonist protocol. In the current study, subgroup analyses from the German IVF registry (DIR) were performed to evaluate the hypothesis that GnRH antagonists are often used as second-line medication in patients with difficult medical conditions, and thus pregnancy rates may be biased. Consequently, pregnancy rates in the first six stimulation cycles (low rank cycles) were more favourable in the group treated according to the long protocol, while in the patient group requiring more stimulation cycles (high rank cycles; 7, 9 and 10), numerically higher pregnancy rates were achieved with GnRH antagonist protocols. On the other hand, in a patient collective with equal demographic and clinical features (<35 years, tubal infertility), the long and the GnRH antagonist protocols resulted in similar pregnancy rates, supporting the hypothesis that both stimulation protocols lead to equal results.

[Receptors for luteinizing hormone releasing hormone expressed on melanoma, renal cell carcinoma and non Hodgkin lymphoma can be used for targeted chemotherapy with cytotoxic luteinizing hormone releasing hormone analogues]

AIMS

Cytotoxic luteinizing hormone releasing hormone (LHRH) analogues AN-152 and AN-207 consist of [D-Lys6] LHRH linked to doxorubicin or its hyperactive derivate AN-201 and bind with high affinity to LHRH receptors. We evaluated the use of AN-207 and AN-201 in a nude mice model. In order to provide a rationale for the possible use of cytotoxic LHRH analogues in different malignancies we investigated the expression of LHRH-R in human renal cell carcinoma (RCC), melanoma and non Hodgkin's Lymphoma (NHL).

METHODS

The expression of LHRH-R was examined in surgically removed human specimens of primary tumours and metastases from 37 RCC, 19 melanomas and 17 NHLs. In addition, human tumour cell lines expressing LHRH receptors were transplanted into nude mice and anti-tumour efficacy and systemic toxicity of AN-207 and its cytotoxic radical AN-201 were compared in various experiments.

RESULTS

Positive staining for LHRH receptors was found in all of the RCC (37/37) and the melanoma specimens (19/19) as well as in 100% (10/10) of the NHLs. In in vivo experiments AN-207 significantly inhibited tumour growth while the cytotoxic radical alone was ineffective. Furthermore, side effects were reduced with targeted therapy.

CONCLUSIONS

LHRH receptor expression was found to be very high in melanomas, RCCs and NHLs. Therefore targeted therapy with cytotoxic LHRH analogues may be a promising, novel therapy for advanced stages of these tumours. A first clinical trial with AN-152 was initiated recently in breast cancer patients.

Extrapituitary effects of GnRH antagonists in assisted reproduction: a review

GnRH antagonists are used to prevent premature LH surges in assisted reproduction. The pregnancy rates obtained in several studies have been similar to those obtained in the long protocol with gonadotrophin-releasing hormone (GnRH) agonists. However, lower oestrogen serum concentrations have been observed and fewer oocytes retrieved using GnRH antagonists. Thus, potential effects at extrapituitary GnRH receptors in the ovary and the endometrium have been claimed. The article reviews the currently available data from the literature as well as current investigations with respect to effects of cetrorelix on the ovary and the endometrium. No evidence was found to support the hypothesis of extrapituitary effects of GnRH antagonists such as cetrorelix at doses used in assisted reproduction.

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.

Single dose application of cetrorelix in combination with clomiphene for friendly IVF: results of a feasibility study

A prospective randomized feasibility study was carried out on 10 patients undergoing IVF treatment using a single-dose LHRH antagonist protocol (cetrorelix, Cetrotide) with clomiphene citrate in combination with either human menopausal gonadotrophin (HMG) (n = 5) or recombinant human FSH (rFSH) (n = 5). Both treatment-groups, HMG and rFSH, were comparable with regard to age (33.2 +/- 2.6 versus 34.4 +/- 4.0 years) BMI (23.2 +/- 2.6 versus 22.7 +/- 1.6) and cause of infertility. They yielded comparable results concerning gonadotrophin dose (19.8 +/- 8.7 versus 17.0 +/- 8.9), stimulation days (6.5 +/- 2.0 versus 5.8 +/- 1.9) and live births (one versus two). No premature LH surge (LH >10 IU/ml and progesterone >1 ng/ml) occurred. The overall baby take-home rate was 30%. In a small number of patients, cetrorelix could be shown to effectively prevent premature LH surges in stimulation protocols combining clomiphene with gonadotrophins with an excellent baby take-home rate per started cycle of 30%.

Use of cetrorelix in combination with clomiphene citrate and gonadotrophins: a suitable approach to 'friendly IVF'?

BACKGROUND

With the recently introduced GnRH antagonists, soft stimulation protocols on the basis of clomiphene pretreatment should be possible as the pituitary remains fully sensitive at the beginning of the cycle.

METHODS

A prospective trial was carried out on 107 patients undergoing IVF treatment using the multiple dose GnRH antagonist protocol (cetrorelix), clomiphene citrate, and either HMG (n = 54) or recombinant FSH (rFSH) (n = 53). Different stimulation protocols were used to find the most appropriate one for clinical application.

RESULTS

Both treatment groups, HMG and rFSH, yielded comparable results concerning gonadotrophin dose, stimulation days and pregnancy rate. A mean number of 6.34 +/- 4.4 metaphase II oocytes was retrieved and a mean number of 2.45 +/- 0.65 embryos was transferred. However, the overall rate of premature LH surges was 21.5% (defined as measurement of LH >10 IU/l and progesterone >1 ng/ml) which is unacceptable for clinical practice.

CONCLUSIONS

Increasing the daily cetrorelix dose from 0.25 to 0.5 mg might decrease the number of premature LH surges. Soft stimulation protocols with clomiphene should be used cautiously.

A memory retraining program for nontoxic chronic alcoholics

This study assessed the effectiveness of a memory rehabilitation program for fifty-nine alcoholics, using a pretest/posttest control group design. The Dooks Memory Test evaluated the different facets of memory, and the Trailmaking Test A and B measured attention and concentration. An analysis of covariance yielded a significant main effect for the Memory Retraining Program (p less than 0.001). The covariate for the composite memory scores was also significantly (p less than 0.025). There was also a significant effect of Age (p less than 0.025) and of IQ p less than 0.002. There were no interaction effects between age and treatment, or IQ and treatment, and no other independent variables (education, duration, days since last drink, depression) were significant. The results point to the potential effectiveness of a memory retraining program for a variety of educational levels, age groups and IQ scores.