Tailoring the GnRH antagonist cetrorelix acetate to individual patients’ needs in ovarian stimulation for IVF: results of a prospective, randomized study

M. Ludwig1,4, A. Katalinic3, C. Banz2, A.K. Schröder2, M. Löning2, J.M. Weiss2 and K. Diedrich2

1 Division of Reproductive Medicine and Gynecologic Endocrinology, 2 Department of Gynecology and Obstetrics, University Clinic, Ratzeburger Allee 160, 23538 Lübeck and 3 Department of Cancer Epidemiology and Social Medicine, Medical University Lübeck, Beckergrube 42–44, 23552 Lübeck, Germany


    Abstract
 Top
 Abstract
 Introduction
 Material and methods
 Results
 Discussion
 References
 
INTRODUCTION: This study was performed to evaluate whether a tailored approach to the administration of the GnRH antagonist cetrorelix acetate according to follicular size leads to a reduction in the amount of Cetrotide® vials used and/or an increased number of monitoring visits. METHODS: Sixty patients were prospectively randomized (using sealed envelopes) to receive either the fixed multiple dose antagonist protocol starting on day 6 of stimulation (group 1), or an individualized protocol with the time of antagonist start according to follicle size (14 mm, group 2), or an individualized single dose protocol (group 3). Recombinant human (rh)FSH was used. The primary endpoints were the number of Cetrotide vials and number of monitoring visits. Statistical power for the parameter Cetrotide vials was 80%. RESULTS: Patients in group 1 needed significantly more Cetrotide vials (6.81 ± 1.61) than patients of group 2 (4.59 ± 1.65; P < 0.01). The number of monitoring visits was similar between the three groups. Surprisingly, the number of retrieved oocytes was significantly higher in the individualized groups as compared with group 1. Despite a significantly lower total amount of rhFSH used, estradiol levels were significantly higher in group 2 as compared with group 1. CONCLUSION: Tailoring of GnRH antagonist protocols leads to an optimization of ovarian stimulation with more oocytes retrieved despite less rhFSH used, and the same number of monitoring visits.

Key words: cetrorelix/follitropin {alpha}/GnRH antagonist/ovarian stimulation/recombinant FSH


    Introduction
 Top
 Abstract
 Introduction
 Material and methods
 Results
 Discussion
 References
 
Since the introduction of GnRH antagonists into the field of ovarian stimulation for IVF, these drugs have been widely used in prospective, randomized studies (Ludwig et al., 2001Go; Al-Inany and Aboulghar, 2002Go). The use of GnRH antagonists provides several advantages for the patient, including a shorter duration of stimulation, fewer ampoules of gonadotrophins, no increased risk of cyst formation, no problem with hormonal withdrawal symptoms, and no risk of administration of a GnRH analogue in early pregnancy.

There is some evidence that tailoring the administration of the GnRH antagonist will lead to an improvement in the outcome of ovarian stimulation cycles (Ludwig et al., 2001Go). This individualization involves the administration of the GnRH antagonist not at a fixed date—as in the clinical studies published so far—but according to the size of the leading follicle.

Therefore, we conducted a prospective, randomized study to analyse whether this tailoring might lead to an increased number of monitoring visits, and fewer ampoules of GnRH antagonist.


    Material and methods
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 Abstract
 Introduction
 Material and methods
 Results
 Discussion
 References
 
Study design
A prospective, randomized, monocentric, open study was performed. Randomization was carried out using sealed envelopes. The study was approved by the local ethics committee of the Medical University Lübeck, Germany. No financial support was given.

Patients
Patients were recruited subsequently from the daily routine practice. Randomization was performed after checking for inclusion and exclusion criteria. Written informed consent was given by the patients before they were included in the study. Patients were free to start ovarian stimulation within the next three spontaneous menstrual cycles.

Inclusion and exclusion criteria
Patients were eligible for inclusion in the study when an indication was present to treat them by IVF or IVF/ICSI, patient’s age was 18–39 years, they had no low response in a previous treatment cycle, no untreated endocrinological disorders (e.g. untreated hyperprolactinaemia, hypothyreosis), no uterine or ovarian anomalies and no contraindication towards use of GnRH antagonists (i.e. known allergic reactions). Patients were free to withdraw from the study at any time.

Ovarian stimulation protocols
In all cycles the GnRH antagonist Cetrotide® was used either in the 0.25 or 3 mg preparation (Serono International S.A., Geneva, Switzerland).

All cycles were started with 150 IU recombinant human (rh)FSH (Gonal F; Serono) on day 2 of the menstrual cycle. Patients were seen for a first ultrasound scan and hormone analysis on day 6 of ovarian stimulation. In group 1, patients received their first Cetrotide 0.25 mg injection from day 6 onwards up to and including the day of hCG (multiple dose fixed protocol).

In the individual groups (groups 2 and 3), Cetrotide 0.25 mg (group 2) and Cetrotide 3 mg (group 3) were started with a demonstrated or expected leading follicle size of 14 mm. When follicles were <=10 mm, Cetrotide was not administered and patients were scheduled for another scan 3 days later. If the follicles were 11–13 mm, Cetrotide was started 1 day later and patients were scheduled for another scan 3 days later. When follicles reached a size of 14–15 mm, Cetrotide was started on the same day and patients were seen 3 days later for the next monitoring visit. When follicles reached a size of >=16 mm, patients returned for the next visit 2 days later, or the medical doctor was free to schedule ovulation induction 2–3 days later. This variability was implemented to allow for an individual schedule of hCG administration in those cases where it was seen, for example during the stimulation procedure, that follicles had an abnormally slow growth pattern.

Where Cetrotide 3 mg was used (group 3) and hCG could not be administered within the next 96 h, additional doses of Cetrotide 0.25 mg were given daily.

Gonadotrophins were given up to and including the day of hCG administration. The same was done for Cetrotide 0.25 mg in the multiple dose protocol groups (2 and 3). Cetrotide 0.25 mg, Cetrotide 3 mg and gonadotrophins all were injected exclusively in the morning. During each monitoring visit, LH and estradiol levels were measured in the routine hormone laboratory.

In all cycles an increase of the gonadotrophin dose used was possible and free to the medical doctor who performed the ultrasound scan. Final follicular maturation was achieved using 10 000 IU hCG (Choragon; Ferring Arzneimittel GmbH, Kiel, Germany).

Cumulative embryo score (modified)
To evaluate the quality of embryos transferred in this study the cumulative embryo score in a modified version (CESm) was used, as previously described (Ludwig et al., 2000cGo). According to the German Embryo Protection Law it is not permitted to generate more embryos than are planned to be transferred in the cycle; therefore, only the quality of the transferred embryos could be assessed.

Statistics
From a large phase IV study, it could be expected that in the individual protocol 6.3 ± 1.5 vials would be necessary (Ludwig et al., 2000bGo). It was expected, that by starting in an individualized scheme, this could be reduced by two vials. To have enough statistical power (alpha 5%, two-sided analysis, power 80%), 15 patients per group were necessary. To have enough patients after taking drop-outs into account, 20 patients per study group were planned to be included.

Statistical analyses were done using {chi}2-test and Mann–Whitney U-Test as appropriate.


    Results
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 Material and methods
 Results
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A flowchart of inclusion, randomization and drop-out of patients is shown in Figure 1Go. In group 2 one patient was excluded from the analysis because she was treated with Cetrotide 3 mg instead of Cetrotide 0.25 mg due to a high LH level (>10 IU) on the first day of ultrasound (cycle day 7). In group 3, two patients did not receive any Cetrotide 3 mg injection because of a low response.



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Figure 1. Flowchart to show the recruited, included, randomized and treated patients in the study. ‘Individual’ means that patients started with Cetrotide when a follicular size of at least 14 mm was achieved.

 
There were no further premature LH rises in this study. Regarding baseline data, the patients were very similar to each other and there were no significant differences between the groups (Table IGo).


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Table I. Baseline data of patients in the three different study groups. Analysed are all patients, who received hCG for oocyte retrieval and were therefore included in the analysis. Data are mean ± SD if not otherwise defined. There were no statistically significant differences between the three groups
 
The outcome of cycles is shown in Table IIGo. There were significantly less vials of Cetrotide 0.25 mg used in the individualized multiple dose group as compared with the fixed multiple dose group (4.59 ± 1.65 versus 6.81 ± 1.61; P < 0.01). On the other hand, the number of monitoring visits was very similar between group 1 (2.83 ± 0.77), group 2 (2.43 ± 0.61) and group 3 (3.09 ± 0.63). The total amount of rhFSH used for ovarian stimulation was significantly less in group 2 (1838 ± 576 IU) as compared with group 1 (2232 ± 624 IU; P < 0.05) and group 3 (2350 ± 618 IU; P < 0.05).


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Table II. Outcome of treatment cycles in the three study groups. Data are mean ± SD if not otherwise defined. Pregnancies were expressed as absolute numbers, because the number was too small to produce reliable percentages
 
Additionally, there was a significant reduction in the number of oocytes retrieved in the group using the fixed scheme (6.15 ± 4.18) as compared with the individual dosage groups. This was true for both the multiple (10.97 ± 7.07; P < 0.05) and single (11.23 ± 9.51; P < 0.05) dose protocols.

In group 3, in 7/18 cycles (39%) additional injections of Cetrotide 0.25 mg were necessary. If only those cycles which had at least one additional vial of Cetrotide 0.25 mg were analysed, there were 2.42 ± 1.61 additional vials.


    Discussion
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 Abstract
 Introduction
 Material and methods
 Results
 Discussion
 References
 
This prospective, randomized study has shown an improved outcome of Cetrotide cycles, when a tailored as compared with a standardized fixed protocol is used to schedule the start of the GnRH antagonist. With a lower amount of rhFSH, and less vials of Cetrotide, a higher yield of oocytes could be achieved in the multiple dose protocol. This clearly shows that tailoring treatment to patients’ needs will further improve the ovarian stimulation protocol using GnRH antagonists. However, some results have to be interpreted with caution.

First, in a higher percentage of patients, the dose of gonadotrophins was increased during ovarian stimulation in groups 1 and 3. The individual medical doctor who did the monitoring was free to do this. Retrospectively, this could have been avoided by defining in the study protocol that the starting dose of 150 IU should not be changed throughout stimulation. This would be in line with the results of others, who have clearly shown that an increase in the gonadotrophin dose during stimulation will not change any of the outcome parameters (Pantos et al., 1990Go; van Hooff et al., 1993Go). On the other hand, despite a lower rate of increasing dosage, in group 2 a higher number of oocytes could be retrieved as compared with group 1, and a similar number as compared with group 3. Since a higher starting dose or a higher total amount of gonadotrophin should result in a greater number of oocytes, but should not change the cycle outcome (Wikland et al., 2001Go), this is a remarkable finding. It further confirms the success of tailoring.

Some doctors may have tended to increase the dose of gonadotrophin in the 3 mg Cetrotide tailored protocol because they were afraid of an estradiol drop and a potential detrimental outcome. However, even if such an estradiol drop occurs, it does not appear to harm follicular growth or pregnancy rates in a 3 mg Cetrotide protocol (F.Olivennes, personal communication).

Second, an estimation of pregnancy rates was not possible from the present data because the groups of patients were much too small to reliably calculate these rates. As far as it is possible to say, the outcome regarding pregnancy rates in the tailored protocols was no worse.

Third, Olivennes et al. have described a rate of 91% of patients who could go through their stimulation cycle with only one vial of Cetrotide 3 mg (Olivennes et al., 2000Go). This rate was decreased in our series to 61%. This may be explained by the fact that we saw patients 1 day earlier—day 6 instead of day 7 of ovarian stimulation—as compared with the original 3 mg protocol. Furthermore, our selection criteria might have been less strict than in the phase III study of Olivennes et al. (Olivennes et al., 2000Go).

Our data showed that the number of Cetrotide 0.25 mg vials was reduced in the individualized group. Since this was an open study and the team was aware of the randomization groups of the individual patients, an influence on the time point of ovulation induction could be discussed. However, we have defined strict criteria for induction of ovulation and performed, especially for patients in this study, oocyte retrievals and embryo transfers 7 days of the week. Therefore, this influence is very unlikely.

Interestingly, despite a lower amount of rhFSH used in group 2, there were significantly higher estradiol levels on the day of hCG administration (Table IIGo). This also reflects changes in the pattern of follicular development. A similar, but not significant, increase in estradiol levels was seen for group 3. It may be that tailoring of the Cetrotide protocols will lead to follicular growth dynamics which are more similar to those of the long protocol than those observed in the standardized protocols with a fixed start (Ludwig et al., 2000aGo). To support this, a more extensive study of follicular development with the measurement of follicular dynamics every second day would be necessary.

Finally, we have used very strict criteria for the start of Cetrotide administration in the tailored study groups. Using less strict criteria and an even more individualized approach may further reduce the number of necessary vials. Those individual situations may be when a leading follicle of 14 mm is present, but the total number of follicles of >10 mm size is still small (e.g. less than three follicles). On the other hand, one has to be aware of the possibility of a premature LH rise. Therefore, Cetrotide administration should not be delayed too long, so that prevention of the LH surge—which has been shown to be slightly less effective as compared with the long protocol (Al-Inany and Aboulghar, 2002Go)—is still guaranteed.

To conclude, we could show that scheduling the Cetrotide start in an ovarian stimulation protocol for IVF by the size of the leading follicle improves the outcome of these cycles according to the measures analysed. The costs for ovarian stimulation can be reduced by a reduction of the amount of gonadotrophins used, as well as by the lower number of Cetrotide vials. Additionally, more oocytes can be achieved with the same number of monitoring visits. Regarding the single dose protocol, these advantages are not as apparent when compared with the fixed multiple dose protocol. It may be that the single dose protocol is optimal for good responder patients, and that in this group the number of additional injections of Cetrotide 0.25 mg can be reduced to a minimum or can be totally avoided. However, since the groups are small and the statistical power was calculated only for the number of monitoring visits and the number of Cetrotide vials, these results remain to be confirmed on a larger scale.


    Notes
 
4 To whom correspondence should be addressed. E-mail: Ludwig_m{at}t-online.de Back


    References
 Top
 Abstract
 Introduction
 Material and methods
 Results
 Discussion
 References
 
Al-Inany, H. and Aboulghar, M. (2002) GnRH antagonists in assisted conception: a Cochrane Review. Hum. Reprod., 17, 874–885.[Abstract/Free Full Text]

Ludwig, M., Felberbaum, R.E., Devroey, P., Albano, C., Riethmüller-Winzen, H., Schüler, A., Engel, J. and Diedrich, K. (2000a) Significant reduction of the incidence of ovarian hyperstimulation syndrome (OHSS) by using the LHRH antagonist Cetrorelix in controlled ovarian stimulation for assisted reproduction. Arch. Gynecol. Obstet., 264, 29–32.[ISI][Medline]

Ludwig, M., Felberbaum, R.E., Hamm, W., Riethmüller-Winzen, H., Ulrich, H. and Diedrich, K. (2000b) Cetrorelix (Cetrotide®) im Mehrfachgabe—Protokoll zur ovariellen Stimulation bei der IVF. Reproduktionsmedizin, 16, 390–399.

Ludwig, M., Schöpper, B., Katalinic, A., Sturm, R., l-Hasani, S. and Diedrich, K. (2000c) Experience with the elective transfer of two embryos under the conditions of the German Embryo Protection Law: results of a retrospective data analysis of 2573 transfer cycles. Hum. Reprod., 15, 319–324.[Abstract/Free Full Text]

Ludwig, M., Katalinic, A. and Diedrich, K. (2001) Use of GnRH antagonists in ovarian stimulation for ART compared with the long protocol: a meta-analysis. Arch. Gynecol. Obstet., 265, 175–182.[Medline]

Olivennes, F., Belaisch-Allart, J., Emperaire, J.C., Dechaud, H., Alvarez, S., Moreau, L., Nicollet, B., Zorn, J.R., Bouchard, P. and Frydman, R. (2000) A prospective randomized controlled study in IVF–ET with a single dose of a LH-RH antagonist (Cetrorelix) or a depot formula of a LH-RH agonist (Triptorelin). Fertil. Steril., 73, 314–320.[ISI][Medline]

Pantos, C., Thornton, S.J., Speirs, A.L. and Johnston, I. (1990) Increasing the human menopausal gonadotropin dose—does the response really improve? Fertil. Steril., 53, 436–439.[ISI][Medline]

van Hooff, M.H., Alberda, A.T., Huisman, G.J., Zeilmaker, G.H. and Leerentveld, R.A. (1993) Doubling the human menopausal gonadotrophin dose in the course of an in-vitro fertilization treatment cycle in low responders: a randomized study. Hum. Reprod., 8, 369–373.[Abstract]

Wikland, M., Bergh, C., Borg, K., Hillensjo, T., Howles, C.M., Knutsson, A., Nilsson, L. and Wood, M. (2001) A prospective, randomized comparison of two starting doses of recombinant FSH in combination with cetrorelix in women undergoing ovarian stimulation for IVF/ICSI. Hum. Reprod., 16, 1676–1681.[Abstract/Free Full Text]

Submitted on June 7, 2002; accepted on July 23, 2002.