1 NV Organon, PO Box 20, 5340 BH Oss, The Netherlands, 2 The Fertility Clinic G-114, Herlev Hospital, Herlev'Ringvej, Herlev, 2730 Denmark, 3 Monash University, Department of Obstetrics and Gynaecology & Monash IVF, Clayton Road, Clayton, Melbourne, Victoria 3168, Australia, 4 Division of Reproductive Medicine, Department of Obstetrics and Gynecology, 737 Parkdale Ave, Ottawa, Ontario K1Y 1J8, Canada, 5 Hospital de Cruces, Pza. de Cruces, s/n, 48903 Barakaldo (Vizcaya), Spain and 6 Instituto Valenciano de Infertilidad, Guardia Civil, 23, 46020 Valencia, Spain
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Abstract |
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Key words: ICSI/IVF/ovarian stimulation/Puregon®?/recombinant FSH
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Introduction |
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Furthermore, pharmacokinetic/-dynamic studies with recombinant FSH have shown that follicular growth continues for 4 days after cessation of recombinant FSH administration (Porchet et al., 1994; Mannaerts et al., 1996). Because of the lag between drug administration and follicular growth, the follicular consequences of any change in the FSH dose are not seen for at least 4 days. As the average treatment period of ovarian stimulation regimens in down-regulated women lasts for 1011 days, the usefulness of dose changes may be questioned.
With increased potency of recombinant FSH (Out et al., 1995), it becomes even more important to select the optimal gonadotrophin dose for ovarian stimulation. The availability of recombinant FSH in 50 and 100 IU ampoules allows for the study of new dosage regimens in clinical trials. Finally, the financial costs associated with the use of recombinant FSH justify a study to determine the best results with the least amount of drug. Therefore, the efficacy and efficiency of a fixed-dose regimen of 100 IU with that of 200 IU recombinant FSH (Puregon) in women undergoing ovarian stimulation was compared.
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Materials and methods |
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Selection of patients
Inclusion criteria were as follows: at least 18 and at most 39 years of age at the time of screening; cause of infertility potentially solvable by IVF or ICSI; normal ovulatory cycles with a mean length of between 24 and 35 days; good physical and mental health; and a body mass index (BMI) between 18 and 29 kg/m2.
Exclusion criteria were: infertility caused by endocrine abnormalities such as hyperprolactinaemia, polycystic ovary syndrome, and absence of ovarian function; previous ovarian stimulation cycles in which less than three oocytes were retrieved; chronic cardiovascular, hepatic, renal, or pulmonary disease; a history of (within 12 months) or current abuse of alcohol or drugs; administration of non-registered investigational drugs within 3 months prior to screening.
When all inclusion criteria and none of the exclusion criteria were met, the subject was considered to be eligible. The study population was thought to be reasonably representative for patients visiting an IVF clinic.
Study drugs and study procedures
Pre-treatment with a gonadotrophin-releasing hormone agonist (GnRHa) for pituitary down-regulation was started either on the first day of the menstrual cycle or in the midluteal phase. All available GnRHa were allowed except the i.m. depot preparations. Recombinant FSH (follitropin beta, Puregon®; NV Organon, Oss, The Netherlands; Batch nos. CP 096025 and 096026) was supplied as lyophilized spheres in ampoules containing 50 or 100 IU FSH in-vivo bioactivity. For s.c. injection, two ampoules were reconstituted with 1 ml solvent (0.45% NaCl). Human chorionic gonadotrophin (HCG, Pregnyl®; NV Organon; Batch nos. CP 096032 and CP 096033) in doses of 5000 IU per ampoule was supplied to trigger ovulation. For i.m. injection of HCG, two ampoules were reconstituted with 1 ml solvent (0.9% NaCl).
During the admission visit, demographic and other subject variables were obtained. In addition, the general medical and gynaecological history were obtained, a general medical and gynaecological examination was performed, and an endocrinological, a biochemical, and haematological analysis of blood was performed. All general medical, biochemical and haematological measurements were performed according to routine procedures of the individual study centres. Eligible subjects were randomized by receiving a subject number from a randomization list corresponding with patient boxes in which the medication was kept. The 50 and 100 IU ampoules were indistinguishable. The randomization was done in blocks of four and was computer-generated using random numbers.
When down-regulation was achieved, defined as oestradiol serum concentrations <200 pmol/l, treatment with recombinant FSH was started and continued until at least three follicles 17 mm had developed. Dose adaptations were not allowed. The maximum treatment period was 3 weeks. HCG (10 000 IU) was given to trigger ovulation. After oocyte retrieval and IVF or ICSI, a maximum of three embryos was replaced. Luteal phase support was given according to the preference of the treatment centre.
Serum concentrations of oestradiol, progesterone, FSH and luteinizing hormone (LH) were measured at baseline (moment of down-regulation) and on the day of HCG injection using local assays. Cycle monitoring included frequent vaginal ultrasound investigations and oestradiol measurements.
Study end-points
The primary efficacy endpoint was the number of oocytes retrieved and the primary efficiency endpoint was the total dose of recombinant FSH used.
Secondary variables included the number of follicles 17,
15,
13 and
11 mm at the day of HCG administration, concentrations of FSH, LH, progesterone and oestradiol at the day of HCG administration, treatment length, embryo development rate, the number of transferable embryos, clinical pregnancy rate, implantation rate, miscarriage rate, and vital pregnancy rate.
Classification of oocytes as either mature or immature, and embryos as type 1, 2, 3 or 4 was done according to previously published criteria (Staessen et al., 1989). Type s1, 2 and 3 were considered to be transferable embryos. The embryo development rate was defined as the number of transferable embryos divided by the total number of oocytes incubated with semen (in conventional IVF) or injected (in ICSI).
The implantation rate was defined as the number of gestational sacs seen on ultrasound examination divided by the total number of embryos replaced. A vital pregnancy was defined as an intrauterine pregnancy with positive heart action. No strict definition of the ovarian hyperstimulation syndrome was given. In the analysis of the occurrence of this syndrome, its incidence was based on the fact that it was reported as such by the investigator.
Statistical analysis
The analysis of variance (ANOVA) was performed for non-dichotomous variables. If the ANOVA was not applicable, the Wilcoxon rank sum test was done. To communicate the Wilcoxon results in clinically meaningful entities, Cochran's method adjusted for centre was used. Dichotomous variables were analysed by MantelHaenszel statistics, adjusted for centre. The statistical analysis included all subjects who received at least one injection of recombinant FSH.
Sample size considerations
With 100 subjects included in each treatment group and assuming a SD of 450 IU of recombinant FSH for the total dose used and a SD of 6.4 oocytes for the number of oocytes retrieved, a difference of 180 IU recombinant FSH and 2.5 oocytes could be detected between the two treatment groups with a power of 80% using a two-sided t-test and a significance threshold of 5%.
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Results |
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Both groups had comparable demographic and infertility characteristics (see Table I). The main causes of infertility were male infertility (n = 37 versus n = 24 in the low- and high-dose groups, respectively) and tubal disease (n = 27 versus n = 28). The mean duration of infertility was 5.25 years for the 100 IU group and 5.00 years for the 200 IU group.
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All women but one were down-regulated at the start of recombinant FSH treatment. Mean oestradiol concentrations prior to ovarian stimulation were 89 and 95 pmol/l in the 100 IU and 200 IU groups, respectively. The corresponding LH concentrations were 3.0 and 2.6 IU/l.
Primary endpoints
Results on the primary efficacy and efficiency endpoints are given in Tables II and III.
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Secondary endpoints
Results on the secondary variables are given in Table IV. The mean number of follicles
11 mm on the day of HCG administration was 13.1 in the high-dose group and 9.9 in the low-dose group (P < 0.001). Correspondingly, significantly more follicles
13 and
15 mm had developed in the high-dose group. The numbers of follicles
17 mm were similar in both groups (5.1 and 5.6 in the low-dose and high-dose treated women, respectively). On average, the treatment length was nearly 2 days longer in the low-dose group (11.2 days) as compared to the high-dose group (9.3 days, P < 0.001).
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LH concentrations did not differ (2.0 versus 1.7 IU/l).
In total, 56 women (34%) went through ICSI and 108 (66%) received conventional IVF. Per group, 37 and 63% received ICSI and IVF, respectively in the 100 IU treated women, whereas 32% had ICSI and 68% IVF in the 200 IU group.
After conventional IVF, significantly more transferable embryos were obtained in the 200 IU group (6.4 versus 4.1, P < 0.001). Although more embryos were also obtained in the 200 IU treated women who underwent ICSI (4.4 versus 3.7), this difference was not significant.
The overall embryo development rate was higher after IVF (57 and 60% in the low- and high-dose groups) than after ICSI (46 and 52%, respectively). Between-group differences, however, were not significant. The centre-adjusted mean number of embryos transferred was 2.0 in the low-dose group and 2.1 in the high-dose group (not significant).
Nearly one embryo more (n = 1.7 versus n = 0.8) was frozen in the 200 IU group as compared to the 100 IU group (P = 0.004).
The clinical pregnancy rates were not statistically significantly different in the low- and high-dose groups, both per started cycle (24.7 versus 23.3%, respectively) and per embryo transfer (36.1 versus 29.0%, respectively). The miscarriage rate in the 100 IU group was significantly higher as compared to the 200 IU group (13.3 versus 1.2% per embryo transfer, P = 0.003). Vital pregnancy rates were not significantly different (15.8% in the 100 IU group, compared to 22.3% in the 200 IU group). Per embryo transfer, the vital pregnancy rates were 22.7 and 27.7% in the low-dose and high-dose groups, respectively (not significant).
The overall incidence of miscarriages (nine patients in the 100 IU group and one in the 200 IU group) was equally distributed among the centres. No common feature in these cases could be identified. In eight cases ultrasounds were done, showing a gestational sac in six of them. None of the pregnancies that aborted had any prior recorded heart activity.
Cycle cancellations
Of 101 women that started in the low-dose group, 77 had an oocyte retrieval (76%) and 70 an embryo transfer (69%). In the high-dose group, 89 (91%) women out of 98 who started recombinant FSH treatment had a retrieval and 83 (85%) had an embryo transfer.
Reasons for cancellation differed between the two treatment groups. In the low-dose group, insufficient ovarian response (n = 24), no fertilization (n = 6) and other (n = 1) were reported. In the high-dose group, the reasons for cancellation were risk for hyperstimulation (n = 6), insufficient ovarian response (n = 3), no fertilization (n = 5) and other (n = 1).
From the 24 low responders in the low-dose group, two did not show sufficient compliance with the treatment. Of the remaining 22 women, the average age and BMI were 33.0 years and 24.2 kg/m2, respectively. The duration of infertility was 4.28 years and the total recombinant FSH dose used was 1356 IU. The percentage of low responders was highly variable for the different centres. In one centre this was 79% (11 out of 14), whereas in the other four centres the percentages were 3% (one out of 30), 5% (one out of 21), 22% (four out of 18) and 28% (five out of 18).
Safety
Seven hospitalizations due to serious adverse events were noted in the 200 IU group, compared to two in the 100 IU group. One patient in each group had an ectopic pregnancy and one a gastrointestinal syndrome (200 IU group). Hospitalization due to ovarian hyperstimulation syndrome or abdominal pain referred to as gynaecological was observed in five patients in the 200 IU group and one in the 100 IU group.
In total, abdominal pain of gynaecological origin and (or) ovarian hyperstimulation syndrome were more often reported in the 200 IU group (13 patients, 13.3%), than in the 100 IU group (three patients, 3.0%).
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Discussion |
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Recently, the extensive use of drugs for ovarian stimulation has been questioned (Edwards et al., 1997). Minimizing the administration and hence the exposure of women to exogenous FSH not only reduces side-effects, but also decreases the costs of IVF treatment. While the lower dose group used less FSH (817 IU less) and had more than twice as high a cancellation rate, there was no significant difference in the pregnancy rates per started cycle between the two groups. The fact that with 200 IU of recombinant FSH daily more oocyte retrievals could be done apparently did not increase the pregnancy rate per initiated cycle. However, it should be emphasized that the study did not have sufficient statistical power to exclude clinically relevant differences in pregnancy rates nor was it set up to primarily look at pregnancy rates.
This study shows that in a considerable subset of patients the FSH threshold can be surpassed and that the FSH window can be maintained with a 100 IU fixed dose, leading to multiple follicular development, as also described previously (Devroey et al., 1998).
An important factor potentially contributing to the observed differences in the current study is variation between clinics. The mean number of oocytes retrieved in the 100 IU group ranged from 1.64 to 7.52 among the five centres. The cycle cancellation rate in the 100 IU group due to low response ranged from 3 to 79%. Apparently, a common protocol as used in this study can still lead to large differences in treatment outcome. Potential factors explaining these variations are patient selection, too early cessation of FSH stimulation, local aspiration techniques, and too much emphasis on oestradiol monitoring.
It is clear that more oocytes and therefore more embryos were available for transfer and freezing in the high-dose regimen. This might result in superior pregnancy rates when the results of the frozenthawed embryo replacements are included, as illustrated previously (Out et al., 1995; Jones et al., 1997
; Society for Assisted Reproductive Technology and the American Society for Reproductive Medicine, 1998
). The fact that the fresh pregnancy rates were similar is likely to be the result of a similar number of embryos transferred in both groups.
The progesterone concentrations on the day of HCG administration were significantly higher in the 200 IU group. It has been suggested that such elevations are detrimental for IVF outcome (Harada et al., 1995). However, that was not found in the current study. It seems likely that the increased progesterone concentrations are related to a greater FSH exposure leading to an increased FSH-induced LH receptivity in granulosa cells (Ubaldi et al., 1996
).
The observed increased miscarriage rate in the 100 IU group was puzzling. No clear explanation was apparent looking at the individual profiles of the patients involved, including their LH concentrations, cause of infertility, age, obstetric history and oestradiol concentrations at day of HCG. Since the miscarriage rate in the 200 IU group was very low (only one patient), it could be speculated that this difference is a coincidental non-specific finding. It should also be stressed that the miscarriage rate was not a primary outcome parameter of this study. In the lack of a plausible biological explanation, future studies will have to confirm whether this increased miscarriage rate is related to FSH dose or not.
A better treatment outcome with higher doses of gonadotrophins is not so obvious, as reported previously by Stadmauer et al., (1994) who showed in a retrospective analysis of 264 cycles with embryo transfer after leuprolide down-regulation that both a higher average daily dose and a higher total dose per cycle were associated with lower clinical pregnancy rates. In another study by Ben-Rafael et al., (1987), 57 patients received two and 57 received three ampoules of HMG in an IVF programme. Significantly fewer atretic oocytes and a higher pregnancy rate were seen in the low-dose group (22.8 versus 10.5%, not significant). However, an inferior ovarian response after the use of a 150 IU dose of HMG as compared to 225 IU has also been reported (Abu-Heija et al., 1995).
A full assessment of the advantages and disadvantages of a 100 versus 200 IU fixed-dose regimen can only be done when all relevant factors are taken into consideration, such as the availability of embryo freezing, the individual clinic's success rate with frozenthawed embryo replacements, the reimbursement of treatment (drug) costs, and prognostic characteristics of the patient. It therefore might very well be that the final selection of a dosage to be used is different from centre to centre.
In conclusion, a 100 IU fixed daily dose of recombinant FSH is less efficacious than 200 IU as shown by a lower number of oocytes retrieved. However, a lower total dose is used to reach pre-ovulatory conditions with 100 IU daily. It seems that pregnancy rates are not influenced by the FSH doses.
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Acknowledgments |
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Notes |
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References |
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Submitted on July 22, 1998; accepted on November 30, 1998.