Induction of ovulation in women undergoing assisted reproductive techniques: recombinant human FSH (follitropin alpha) versus highly purified urinary FSH (urofollitropin HP)

E. Lenton1,6, A. Soltan1, J. Hewitt2, A. Thomson2, W. Davies3, N. Ashraf3, V. Sharma4, L. Jenner4, W. Ledger5 and E. McVeigh5

1 Sheffield Fertility Centre, Sheffield, S7 1RA, 2 Reproductive Medicine Unit, Liverpool Women's Hospital, Liverpool L8 7SS, 3 Cliftonville Suite, Three Shires Hospital, Northampton NN1 5DR, 4 Assisted Conception Unit, St James's Hospital, Leeds LS9 7TF and 5 Nuffield Department of Obstetrics and Gynaecology, John Radcliffe Hospital, Oxford OX3 9DU, UK


    Abstract
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 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
This multicentre, open, randomized, study compared the efficacy and safety of recombinant follicle stimulating hormone (rFSH; follitropin alpha) with highly purified urinary human FSH (uFSH; urofollitropin HP) in women undergoing ovulation induction for assisted reproductive techniques. Following long down-regulation with buserelin, patients received two ampoules of 75 IU (150 IU) s.c. rFSH or highly purified uFSH for 6 days, after which the dose could be increased until they fulfilled the criteria for human chorionic gonadotrophin (HCG) administration. Of 168 patients recruited, 155 received at least one dose of FSH, and 137 received HCG [68: rFSH (85%); 69: uFSH (92%)]. Following oocyte retrieval and fertilization, up to three embryos were replaced/patient and luteal support was given. The mean number of oocytes retrieved/patient was 10.2 ± 6.0 for rFSH patients compared with 10.8 ± 6.1 in the uFSH group (not significant). There was a trend towards fewer ampoules used (22.3 ± 6.5 versus 24.3 ± 6.5), higher pregnancy (44.3 versus 41.4%) and live birth rates (33.8 versus 26.7%), as well as a lower miscarriage rate (0.0 versus 16.7%) in favour of rFSH. However, no significant differences in efficacy parameters were recorded. Ovarian hyperstimulation syndrome occurred in 8.6% and 7.9% of rFSH and uFSH patients respectively. In conclusion, this protocol was effective in inducing multiple follicular development and high numbers of oocytes were retrieved with both drugs.

Key words: highly purified human uFSH/human rFSH/ICSI/IVF/multiple follicular development


    Introduction
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 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
During IVF, it is accepted that the presence of multiple fertilized oocytes is correlated with the chance of a pregnancy and successful live birth (Templeton and Morris, 1998Go). Ovarian stimulation using daily administration of gonadotrophins in conjunction with a gonadotrophin releasing hormone (GnRH) agonist (e.g. buserelin) enables the production of multiple oocytes that can be used for fertilization (Hamberger and Wikland, 1993Go). Down-regulation with a GnRH agonist suppresses endogenous gonadotrophin production, improving folliculogenesis and inhibiting the spontaneous LH surge. This has resulted in fewer cancelled cycles, higher numbers of oocytes and more pregnancies (Smitz et al., 1987Go; Loumaye, 1990Go; Hughes et al., 1992Go). Additionally, it has simplified protocols and improved convenience for clinicians and their patients in terms of reducing weekend egg collections, for example.

Human menopausal gonadotrophin (HMG) may be used as a source of FSH, but it has low specific activity and contains significant amounts of LH (as well as other proteins), which is thought to lead to poor oocyte quality, reduced fertilization rates, lower embryonic viability and early pregnancy wastage (Stanger and Yovich, 1985Go; Homburg et al., 1988Go; Punnonen et al., 1988Go; Daya et al., 1995Go). The development of other urine-derived FSH preparations (urofollitropin and highly purified urofollitropin), which contain significantly reduced or negligible quantities of LH, has resulted in higher pregnancy rates than with HMG (Howles et al., 1994Go; Wikland et al., 1994Go; Daya et al., 1995Go). Nevertheless, all urinary-derived preparations have the drawback of requiring the collection of large quantities of urine from multiple donors, leading to variability in supply and, perhaps most importantly, batch-to-batch inconsistency.

Recently, developments in biotechnology have led to the development of two recombinant human FSH preparations [rFSH, follitropin alpha and follitropin beta (Chappel et al., 1992Go; Olijve et al., 1996Go)] which are devoid of any LH activity and extraneous human protein. This technology has three advantages: FSH production is independent of urine collection, a constant FSH supply is ensured and batch-to-batch consistency can be guaranteed. The highly effective purification process yields FSH preparations with a specific activity of >10 000 IU/mg protein, thus these recombinant products are the most biochemically pure for clinical use (Loumaye et al., 1995Go; Recombinant Human FSH Product Development Group, 1998Go). The high purity is thought to confer safety and tolerability advantages. For example, in women who have suffered local and systemic adverse reactions following injection of urinary gonadotrophin preparations, the administration of s.c. rFSH (follitropin alpha; Serono Pharmaceuticals, UK) has been associated with good tolerance at the site of injection and reduced immunogenicity (Redfearn et al., 1995Go; Albano et al., 1996Go).

Initial clinical studies in IVF established the efficacy and safety of rFSH in stimulating multiple follicular development, with or without concurrent GnRH agonists (Devroey et al., 1994Go; Fisch et al., 1995Go; Hedon et al., 1995Go; Recombinant Human FSH Study Group, 1995Go; Strowitzki et al., 1995Go; Out et al., 1997Go; Jansen et al., 1998Go), and showed that rFSH was at least as effective as uFSH (Hedon et al., 1995Go; recombinant Human FSH Study Group, 1995Go) or HMG (Jansen et al., 1998Go). Retrospective and prospective comparisons of rFSH with highly purified uFSH now suggest that rFSH may be more effective in stimulating follicular development, without any increase in the risk of ovarian hyperstimulation syndrome (OHSS) (Out et al., 1995Go; Bergh et al., 1997Go; Frydman et al., 2000Go; Khalaf et al., 2000Go). Interestingly, data comparing the two available rFSH preparations, rFSH (follitropin alpha) and rFSH (follitropin beta) indicate that, although the two preparations appear to be clinically equivalent, there are differences in tolerability in favour of rFSH (follitropin alpha) (Fried et al. 1998Go; Brinsden et al., 2000Go), which has been confirmed by Afnan et al. (M.A.Afnan, A.Kennefick, R.Burston and Y.Khalaf, manuscript submitted).

The starting dose of FSH, and minimization of FSH usage while maintaining efficacy are two issues that continue to be important in relation to ovulation induction protocols for IVF. The starting dose of FSH in normally ovulating women undergoing IVF is 150–225 IU/day, depending on their age, and although recent studies (Thornton, 1996Go; Camier et al., 1998Go) have suggested that 150 IU/day may be just as effective as 225 IU/day in terms of oocyte retrieval, fertilization and pregnancy, another study has shown the 150 IU/day dose to be inferior (Abu-Heija et al., 1995Go). However, the age of the patient population treated may also be an important factor in determining response. Results from a small study (Devroey et al., 1998Go) have shown that a starting dose of 100 IU/day is suboptimal in normally menstruating women. In terms of minimization of usage, two studies (Bergh et al., 1997Go; Frydman et al., 2000Go) found a significant overall reduction in the number of FSH treatment days and numbers of ampoules used with 150 IU/day rFSH (follitropin alpha) compared with 150 IU/day highly purified uFSH. Thus, the use of rFSH may also have cost–benefit implications.

This study was designed to compare rFSH with uFSH using a low-dose protocol (150 IU/day) following long down-regulation with a GnRH agonist (buserelin) in five centres in the UK. It compared the efficacy and safety of highly purified uFSH with rFSH (follitropin alpha) in inducing ovulation for one cycle of IVF/intracytoplasmic sperm injection (ICSI).


    Materials and methods
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 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
Patient selection
Patients were recruited between January 1997 and February 1998. Pre-menopausal women, aged 18–38 years, were eligible for the study if they satisfied the following criteria: (i) infertility attributable to any of the following: tubal factor, American Fertility Society (AFS) grade I or II endometriosis (The American Fertility Society, 1985), male factor or unexplained fertility; (ii) first cycle of assisted reproduction treatment; (iii) regular, spontaneous ovulatory menstrual cycles of 25–35 days; (iv) body mass index (BMI) >=18 but <=26 kg/m2; (v) presence of both ovaries and normal uterine cavity; (vi) no treatment with gonadotrophins in the month prior to the study; (vii) willing to participate in the study and comply with procedures.

Patients were excluded from the study if (i) they had a previous poor or hyper-response to gonadotrophins; (ii) they had a previous history of severe OHSS; (iii) polycystic ovarian syndrome; (iv) the male partner had azoospermia or clinical signs of infection detected in a semen analysis within the 12 months prior to the treatment cycle; (v) they had a clinically significant condition.

All patients gave their written informed consent. The study was approved by the local ethics committee for each centre.

Study design
This was an open, randomized, parallel-group, multicentre study carried out at five hospitals throughout the UK. The study was designed to compare the efficacy and safety of rFSH (follitropin alpha; Serono Pharmaceuticals, Middlesex, UK) with highly purified urinary hFSH (urofollitropin HP; Serono Pharmaceuticals) during one cycle of ovulation induction for IVF/ICSI. The study was conducted in accordance with the requirements of the Declaration of Helsinki, Good Clinical Practice (GCP) guidelines, Human Fertilisation and Embryology Authority (HFEA) regulations and local requirements.

Patients underwent pituitary desensitization with either 300 µg intranasal buserelin (Suprefact®; Shire Pharmaceuticals Ltd, Andover, UK) three times daily or a single s.c. injection of 0.5 mg/ml, from day 21 of their cycle for a minimum of 10 days prior to receiving gonadotrophin. Patients were considered to be desensitized if an ultrasound scan showed no follicles >10 mm in diameter and an endometrial thickness of <7 mm. If circulating hormone concentrations were measured, they had to be within the accepted reference range at that treatment unit. Patients could receive up to 5 weeks of buserelin treatment prior to starting gonadotrophin, but were withdrawn from the study if they were not desensitized after this time.

After down-regulation, patients were evenly randomized to receive either rFSH or highly purified uFSH. Randomization was carried out using sealed envelopes containing the name of the drug to be used. Randomization was done in blocks of four by centre to ensure similar distributions of each drug throughout the study and in each centre. Both drugs were administered s.c., starting at a fixed dose of 150 IU/day for the first 6 days. Ovarian response was assessed on day 6 and the results were used to evaluate whether a change in dose was required. Dose increments (up to a maximum dose of 450 IU/day) could be made at the investigator's discretion. Patients with a poor response had their cycles cancelled if necessary and, in cases of over-response, patients judged to be at risk of OHSS underwent oocyte retrieval and any resultant embryos were frozen for replacement in a subsequent cycle.

The patient was considered to be sufficiently stimulated to receive human chorionic gonadotrophin (HCG) when the largest follicle had a mean diameter of >=18 mm and there were at least two other follicles with a diameter of 16 mm. HCG (Profasi®; Serono Pharmaceuticals) was administered s.c. or i.m. at a dose of 10 000 IU within 12–16 h of the ultrasound scan which confirmed adequate follicular development. A diary card was used by each patient to record details of any local reactions to the daily FSH injections.

Oocytes were retrieved 34–38 h after HCG administration and assessed according to established criteria before being fertilized in vitro. The resultant embryos were graded and up to three embryos were replaced, 2–3 days after oocyte retrieval. For ICSI, the cumulus cells were removed and an assessment of oocyte nuclear maturity was made. Luteal phase support was initiated either after oocyte retrieval or on the day of embryo transfer. This consisted of commercially available (vaginal pessary or i.m. injection) progesterone preparations being administered. Any remaining embryos were frozen at the request of the patient. Pregnancy was assessed 12–14 days after HCG administration and for patients with a raised serum HCG, ultrasound was used 28 days after egg collection to record the number of fetal sacs.

Efficacy endpoints
The primary efficacy endpoint was the number of oocytes retrieved following HCG administration. Additionally, the following secondary endpoints were recorded: number of 75 IU FSH ampoules used during stimulation; number of days of FSH stimulation; number of follicles >10 mm/>=14 mm/>=18 mm diameter on day of, or day before, HCG administration; number of metaphase II oocytes (ICSI patients only); number of fertilized oocytes; number of two-pronuclear fertilized oocytes; number of cleaved embryos; number of grade 1 or 2 embryos; number of embryos replaced or frozen; fertilization and implantation rates (expressed per patient); clinical and overall pregnancy rate per embryo transfer and per cycle; cancellation rate; number of live births and incidence of moderate or severe OHSS. All endpoints except the number of follicles >=14 mm and 18 mm in diameter, number of embryos replaced or frozen, overall pregnancy rates and incidence of OHSS underwent statistical comparison.

Safety endpoints
Data for the duration of exposure to FSH, adverse events (including incidence of injection-site reactions and OHSS), oestradiol concentrations, premature discontinuations and concomitant medications were summarized for all patients who took at least one dose of study medication. Adverse events were recorded on the basis of the patient's or physician's observations. An adverse event was classified as serious if it was fatal or life-threatening, was permanently disabling, required inpatient or prolonged hospitalization, or was a congenital anomaly, cancer or overdose.

Patient withdrawals
Patients were withdrawn from the study for the following reasons: poor response to the stimulation protocol, risk of OHSS, adverse event, protocol violation, non-compliance or at the patient's or physician's own request.

Sample size and statistical methods
A sample size of 120 evaluable patients in each treatment group would have 99% power to detect a difference in the mean number of oocytes of 2.5. This was based on an expected mean oocyte retrieval in the urofollitropin HP group of 8.4 and assumed a common SD of 4.4 using a two-group t-test with a two-sided significance level of 5%. Therefore a total of 240 evaluable patients was required. Grades of power for different levels of evaluable patients was as follows: 90 patients per group, 96% power; 83 patients per group, 95% power.

Statistical analyses were performed on the following defined populations: `all-patients' (intention-to-treat) population (those who received at least one dose of rFSH or uFSH); `per-protocol' population (those in the intention-to-treat population whose treatment proceeded in accordance with the protocol) and the `safety-evaluable' population (all patients who received at least one dose of buserelin). Efficacy endpoints were analysed using the all-patients population and, in addition, the primary efficacy endpoint (number of oocytes retrieved) was analysed for the per-protocol population. Safety assessments were taken from the safety evaluable population. All analyses were performed using version 6.12 of the SAS® package (SAS Institute, Cary, NC, USA).

The comparability of the two treatment groups at baseline was checked for all demographic data, medical history and clinical examination. The primary efficacy parameter and other continuous endpoints were analysed using a two-way analysis of variance (ANOVA), adjusting for centre and testing for a treatment by centre interaction. Ongoing clinical pregnancy rates and cancellation rates were compared using logistic regression techniques, adjusting for centre and centre by treatment interaction. If neither of these was statistically significant, they were omitted from the model and a comparison of response between groups was made using a conventional {chi}2-test. Descriptive statistics were used for all efficacy parameters.


    Results
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 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
A total of 168 patients was recruited to the study [Sheffield Fertility Centre (n = 71), Liverpool Women's Hospital (n = 32), Three Shires Hospital, Northampton (n = 25), St James's Hospital, Leeds (n = 22), John Radcliffe Hospital, Oxford (n = 18)]; 83 into the rFSH group and 85 into the uFSH group. Eleven patients failed to take any buserelin and were excluded from the safety population, two more (one from each group) did not take any gonadotrophin and were excluded from the all-patients population, and a further 38 patients were protocol violators and were excluded from the per-protocol population. Thus, there were 155 women in the all-patient population with 80 and 75 patients in the rFSH and uFSH groups respectively. This sample size gave 90–95% power to detect a difference in the mean number of oocytes retrieved. The two treatment groups were comparable for demographic characteristics, which included age, BMI, type, cause and duration of infertility (Table IGo).


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Table I. Demographic characteristics of patients (all patients population)
 
Stimulation characteristics
Table IIGo shows the stimulation profile for all patients who received at least one dose of gonadotrophin (i.e. the all-patient population). Of the 155 patients who received at least one dose of FSH, 137 (88.4%) went on to receive HCG; 68 (85%) in the rFSH group and 69 (92%) in the uFSH group. Although the cancellation rate was 15% for the rFSH group and 8% for the uFSH group, this difference was not statistically significant. In both groups, the main reason patients did not receive HCG was inadequate stimulation. The mean number of FSH treatment days was similar in both treatment groups (10.2 ± 2.1 versus 10.7 ± 1.7 days for rFSH and uFSH respectively) and although slightly fewer ampoules were used in the rFSH group (22.3 ± 6.5 versus 24.3 ± 6.5 for the rFSH and uFSH groups respectively), no statistically significant difference was seen.


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Table II. Outcome of stimulation in the two subject groups
 
After 6 days of stimulation, when the first ultrasound scan was performed, there were no significant differences between groups in any of the parameters measured. The mean number of follicles >10 mm observed at ultrasound was 2.2 ± 2.8 in the rFSH group compared with 2.0 ± 3.2 in the uFSH group. Three of the five centres measured oestradiol on day 6, and the mean plasma oestradiol concentration was similar in the rFSH (1339.4 ± 945.5 pmol/l) and uFSH (1150.3 ± 838.8 pmol/l) groups. Endometrial thickness was also similar in both groups: rFSH 7.5 ± 1.8 mm versus uFSH 6.6 ± 2.3 mm. At this stage, the dose of FSH was increased to three or four 75 IU ampoules for 23 patients in the rFSH group (28.8%) and to between three and five 75 IU ampoules for 21 (28.0%) of those receiving uFSH.

As shown in Table IIGo, on the day of HCG administration, the mean number of follicles >10 mm was 12.5 ± 6.0 for the rFSH group compared with 13.1 ± 6.1 for the uFSH group. This difference was not statistically significant. Plasma oestradiol concentrations and endometrial thickness were similar in both groups.

The mean number of oocytes retrieved per patient (primary efficacy parameter) was 10.2 ± 6.0 after rFSH and 10.8 ± 6.1 after uFSH treatment (Table IIIGo). This difference was not significantly different. A similar result was found for the per-protocol population; the mean number of oocytes retrieved was 9.9 ± 5.7 in the rFSH group and 10.9 ± 6.6 in the uFSH group (not significant). This means that excluding patients who did not fully comply with the protocol did not affect the conclusion of the primary endpoint. For the ICSI patients only, a mean of 10.3 ± 5.1 oocytes was retrieved per patient in the rFSH group (n = 23) compared with 10.0 ± 6.5 oocytes in the uFSH group (n = 14). Although no statistical analysis was performed on this subgroup of patients, assessment of their results suggested they would not distort the overall outcome of the study.


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Table III. Embryological characteristics of the two groups
 
For patients undergoing ICSI, an assessment of oocyte maturity was performed. The mean number of metaphase II oocytes was 8.0 ± 4.0 in the rFSH group compared with 6.9 ± 4.2 in the uFSH group (not significant).

Embryological characteristics
The embryological characteristics for patients from whom oocytes were retrieved are shown in Table IIIGo. The mean number of fertilized oocytes per patient was similar in the two groups: 6.3 ± 4.7 for patients receiving rFSH compared with 6.5 ± 4.8 for those receiving uFSH. For patients undergoing ICSI, the mean number of fertilized oocytes was slightly higher in the rFSH group (5.9 ± 3.2) than in the uFSH group (4.2 ± 2.0) (no significant difference). The number of two-pronuclei (2PN) fertilized oocytes on day 1 was similar for both groups of patients when IVF and ICSI patients were combined, though slightly higher for the ICSI-only patients who were receiving rFSH (5.9 ± 3.2 versus 4.1 ± 1.9 for those receiving uFSH).

The fertilization rate obtained in the rFSH group was 63.0% compared to 63.1% for uFSH patients. The mean number of cleaved embryos per patient was 5.5 ± 3.6 in the rFSH group and 5.5 ± 2.8 in the uFSH group. For the ICSI patients receiving rFSH, there were 5.3 ± 2.8 cleaved embryos compared with 3.7 ± 1.9 in those ICSI patients receiving uFSH (not significant). Grading of embryos prior to transfer indicated that there were 4.0 ± 2.4 and 4.4 ± 2.7 grade 1 or 2 embryos per patient in the rFSH and uFSH groups (not significant), respectively; for the ICSI subset, these numbers were lower. The numbers of cryopreserved embryos were similar in both groups (see Table IIIGo).

Embryo transfer and pregnancy
In the rFSH group, 19 patients (23.8%) and in the uFSH group 17 patients (22.7%) did not undergo embryo transfer for the following reasons: intrauterine insemination (IUI) was used, no fertilized oocytes or cleaved embryos were obtained, or all embryos were cryopreserved. Taking into account the numbers of patients not reaching the stages of receiving HCG or undergoing embryo transfer, a similar proportion underwent embryo transfer in each group: rFSH 61 patients (76.3%) and uFSH 58 patients (77.3%). Most patients had two or three embryos transferred in both groups (Table IVGo). For patients receiving rFSH, the mean implantation rate was marginally higher than in the uFSH group: 25.1% versus 20.7%, although the difference between groups was not significant. A total of 31 (50.8%) and 27 (45.8%) patients per embryo transfer in the rFSH and uFSH groups respectively had positive HCG recorded after their treatment cycle. The clinical pregnancy rates per embryo transfer were similar in both groups of patients: 44.3% (27/61) versus 41.4% (24/58) for the rFSH and uFSH patients respectively. As the all-patient population comprised all patients who received at least one dose of FSH, regardless of adherence to the protocol, the data on pregnancy rate included patients who were converted to IUI and became pregnant. One patient in the uFSH group became pregnant as a result of IUI and is included in the pregnancy rate data, even though she did not undergo IVF or ICSI. There were no miscarriages (clinical pregnancies minus live births) in the rFSH group (0/27) compared to a miscarriage rate of 16.7% (4/24) in the uFSH group. The multiple birth rate (proportion of patients with live births who had multiple births) was 37.0% in the rFSH group compared to 30.0% in the uFSH group. There was a 7% difference in the live birth rate per cycle in favour of rFSH, although this was not statistically significant (Table IVGo).


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Table IV. Embryo transfer and pregnancy rates
 
Safety
Overall, the two drugs were well tolerated, with most side-effects being mild in nature. Only one patient (from the rFSH group) was withdrawn from the study because of an adverse event (she developed an ovarian cyst) although she also left the study because of a cancelled cycle. The incidence of adverse events was similar in the two groups, with a total of 51 patients, 25 (30.9%) in the rFSH group and 26 (34.2%) in the uFSH group reporting at least one adverse event. Five patients suffered a serious adverse event; two in the rFSH group (both OHSS) and three receiving uFSH (two cases of OHSS and one case of iliac fossa pain). The incidence of OHSS was similar in both groups; 13 patients were reported to have suffered from this, seven (8.6%) receiving rFSH and six (7.9%) receiving uFSH. Of these, the maximum severity recorded was moderate. Local tolerance to the injections was similar in both groups, with most patients (>70%) reporting either none or mild, pain, tenderness, redness, itching and bruising around the injection site.


    Discussion
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
This study is the first in the UK to compare prospectively the efficacy and safety of a recombinant hFSH preparation (follitropin alpha) with a highly purified urinary comparator (urofollitropin HP) in women undergoing ovulation induction for IVF. The protocol involved a low starting dose of FSH (150 IU/day), which has previously been shown to be effective for multiple follicular development (Thornton, 1996Go).

The primary efficacy endpoint in this study was the number of oocytes retrieved following HCG administration. Encouragingly, stimulation with both agents yielded a high number of oocytes: 10.2 ± 6.0 in the rFSH group compared with 10.8 ± 6.1 in those patients receiving uFSH (no significant difference). Previous studies with rFSH (follitropin alpha) using this low-dose protocol (Bergh et al., 1997Go; Camier et al., 1998Go; Brinsden et al., 2000Go; Frydman et al., 2000Go; Khalaf et al., 2000Go) have also demonstrated high oocyte retrieval (12.2 ± 5.5, 11.2 ± 5.2, 12.1 ± 7.9, 11.0 ± 5.9 and 11.2 ± 4.1 respectively). Clearly, 150 IU/day is effective in stimulating follicular development in this group of women. In the studies that directly compared rFSH (follitropin alpha) with highly purified uFSH (urofollitropin HP) (Bergh et al., 1997Go; Frydman et al., 2000Go; Khalaf et al., 2000Go), the number of oocytes retrieved was lower after uFSH than after rFSH. Furthermore, the difference in oocyte retrieval between groups was statistically significant in favour of rFSH in the studies by Bergh et al. (1997), Khalaf et al. (2000) and Frydman et al. (2000).

The stimulation profiles of the two drugs showed no significant differences in secondary efficacy endpoints in this study, with a similar number of follicles seen on ultrasound, endometrial thickness and oestradiol concentrations attained in both groups. These were achieved using 22.3 ± 6.5 versus 24.3 ± 6.5 FSH ampoules and 10.2 ± 2.1 versus 10.7 ± 1.7 FSH treatment days. It is difficult to compare ampoule usage across studies as each centre has its own policy regarding timing and method for increasing gonadotrophin dose; for example, in this study and one other (Frydman et al., 2000Go), dose increases were permitted after an assessment on day 6, whereas in another study (Bergh et al., 1997Go), increases were allowed after a day 7 assessment. Nevertheless, the slightly lower FSH usage found with rFSH in this study compared with uFSH is consistent with findings in the three previous studies (Bergh et al., 1997Go; Frydman et al., 2000Go; Khalaf et al., 2000Go), two of which found a statistical difference between groups in favour of rFSH (follitropin alpha). In the studies by Bergh et al. (1997) and Frydman et al. (2000) respectively, the number of FSH treatment days was 11.0 ± 1.6 and 11.7 ± 1.9 for rFSH compared with 13.5 ± 3.7 and 14.5 ± 3.3 for uFSH (P <= 0.0001). The numbers of FSH ampoules used in these studies were 21.9 ± 5.1 and 27.6 ± 10.2 for rFSH compared with 31.9 ± 13.4 and 40.7 ± 13.6 for uFSH (P <= 0.0001). For uFSH, these numbers of ampoules are much greater than seen in the current study. These results suggest that the recombinant product may have a higher potency, and this is consistent with a study (Mannaerts et al., 1996Go) which showed a higher bioactivity for rFSH compared with urinary-derived products. The higher number of ampoules used in the study by Frydman et al. (2000), compared with the numbers used in this study and that by Bergh et al. (1997), may be partly explained by the use of a depot down-regulator, which would have caused more profound down-regulation than that following intranasal or s.c. administration of a GnRH agonist (therefore requiring administration of a greater amount of exogenous FSH).

Embryological characteristics were similar in both groups of patients in this study, including the mean number of fertilized oocytes, number of cleaved embryos, number of 2PN fertilized oocytes on day 1 and the number of embryos transferred. Similar fertilization rates were obtained (63%) in both groups, which compares well with previous studies (Bergh et al., 1997Go; Khalaf et al., 2000Go).

For patients undergoing ICSI, similar embryology results were also obtained in both groups; however, the mean numbers of grade 1 and 2 embryos, 2PN fertilized oocytes and cryopreserved embryos were slightly smaller, compared with the study group as a whole. This may be related to the small number of patients undergoing ICSI (n = 37). Interestingly, preliminary data from a study that compared IVF with ICSI in rFSH (follitropin alpha)-treated patients found that fertilization rates were significantly less with ICSI (57%) than with IVF (67%, P < 0.05) (Hamilton et al., 1998Go). Although fertilization rate was not assessed for the ICSI subgroup, this parameter was ~63% for IVF and ICSI patients combined.

Ultimately, for both clinicians and patients, the most important endpoints for assisted reproduction treatments are pregnancy and live birth rates. The chance of success after IVF has been found to be determined by the number of fertilized oocytes, rather than by the numbers of embryos transferred (Templeton and Morris, 1998Go). Thus, with a similar number of fertilized oocytes in both groups, a similar pregnancy rate and live birth rate would have been expected in this study. Similar numbers of patients became pregnant in each group, with clinical pregnancy rates per embryo transfer greater than the pregnancy rate seen in the fertile population: 44.3% for rFSH compared with 41.4% for highly purified uFSH. However, all patients who became pregnant after rFSH delivered a live baby, which was not the case for uFSH; live-birth rates per cycle were 33.8% versus 26.7%, for rFSH and uFSH respectively. This may suggest a clinically relevant result. The pregnancy rate obtained in this study with rFSH is similar to that found in previous studies [Camier et al., 1998 (30%); Brinsden et al., 2000 (32%)], although higher than that found by Frydman et al, 2000 (18%). In general, pregnancy rates have been found to be higher with rFSH (follitropin alpha) than with highly purified uFSH (Bergh et al., 1997Go; Khalaf et al., 2000Go).

This was the conclusion of a meta-analysis recently performed by Daya and Gunby (1999). (The meta-analysis was produced after the completion of this current work and it includes this study in the pool of papers analysed.) The trials which have compared rFSH and urinary FSH have not had sufficient power to detect a clinically meaningful difference in pregnancy rates between the two drugs. The aim of the study by Daya and Gunby (1999) was to determine whether there really is a difference in the clinical pregnancy rates for rFSH and urinary FSH in IVF/ICSI. Data from randomized studies which compared rFSH with urinary FSH were pooled and assessed in accordance with the principles of meta-analysis. The common odds ratio and 95% confidence intervals (CI) were found to be 1.20 and 1.02–1.42 respectively (P = 0.03) in favour of rFSH. This indicates a 20% greater chance of achieving pregnancy with rFSH than uFSH. The risk difference was represented as a 3.7% (95% CI, 0.5–6.9%) increase in pregnancy rate in favour of rFSH. This paper concluded that for assisted reproduction treatments the use of rFSH is preferable to uFSH.

A key to the lack of statistical differences detected for efficacy endpoints in this study may relate to the fact that 38 patients deviated from the protocol exclusion and inclusion criteria, resulting in a more heterogeneous all-patients population than anticipated. As efficacy parameters were based on the all-patients population, this could have affected results. However, the per-protocol assessment of the primary endpoint came to the same conclusion as the all-patients assessment, thus suggesting that inclusion of all-patients' data would not affect the outcome of the study. It should also be noted that in previous studies, uFSH performed less well than it did in this study, whereas results for rFSH are similar throughout, suggesting a reason why there are no statistically significant differences between regimens in this study.

The two drugs were well tolerated, with most injection-site reactions being mild in nature. This may be related to the fact that injections were given s.c. rather than i.m., which has previously been the main route for less pure preparations. However, good local tolerability cannot be predicted for all recombinant preparations. rFSH (follitropin beta), which is also administered s.c., has been found to be less well tolerated locally than rFSH (follitropin alpha) (Afnan et al., 2000; Brinsden et al., 2000Go). The incidence of adverse events was similar in both groups, with most being of a mild nature and not considered to be related to the study drug. An important side-effect in relation to gonadotrophin treatment is OHSS, and its incidence here was not different between the two groups, occurring in 8.6% of patients receiving rFSH (follitropin alpha) and in 7.9% of those receiving highly purified uFSH. It has been shown that the number of oocytes retrieved and the ongoing pregnancy rate are risk factors for this syndrome (Delvigne et al., 1993Go), thus cautious monitoring is always recommended.

In conclusion, both rFSH (follitropin alpha) and highly purified uFSH, at a fixed starting dose of 150 IU/day, were highly effective in producing multiple follicular development and were well tolerated by patients. The trend towards a lower consumption of FSH using rFSH, as well as a higher live-birth rate and lower miscarriage rate, suggests that rFSH may be more cost-effective per treatment cycle than highly purified uFSH.


    Acknowledgments
 
The authors wish to acknowledge Serono Pharmaceuticals (UK) Limited for their financial assistance and support during this study.


    Notes
 
6 To whom correspondence should be addressed at: Sheffield Fertility Centre, 26 Glen Road, Nether Edge, Sheffield, S7 1RA, UK Back


    References
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
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Submitted on October 15, 1999; accepted on February 15, 2000.