SEGÚN HENRI RIVIERE

VI. Discussion

Summary

Studies on ovarian cell growth, differentiation and steroid production suggested that insulin­ like growth factors play an important role in modulation of gonadal function. Clinical application of these in-vitro findings were investigated in the setting of a super-ovulation programme for IVF-ET. Women who had previously responded sub-optimally to various drug regimens were recruited into three separate studies. The ovarian response to gonadotrophin stimulation with additional GH treatment was assessed and the concentrations of IGFs in the circulation and the FFL were established.

Women with raised gonadotrophins did not have an improved response to ovarian stimulation when GH was added. Women with a normal appearance of the ovaries on ultrasound scanning of the pelvis did not show any clinical improvement with GH co-treatment. Women with a polycystic appearance of the ovaries did, however, demonstrate an improved response when treatment with hMG was augmented with GH. The improved response in women with PCO was seen both in the CC and hMG and the buserelin and hMG studies. GH administration was associated with a rise in the concentrations of IGF-I in the circulation. FFL concentrations were higher in GH treated women but significantly lower than serum concentrations.

Access to FFL through the IVF-ET procedures stimulated an interest in the investigation of an intraovarian marker for the subgroup of women with PCO. Detectable concentrations of

I I B - O H - A 4 had been demonstrated in the ovarian veins of an adrenalectomised woman with

PCO and it was postulated that 1113 hydroxylase activity on C19 steroids may occur uniquely in women with PCO. Having developed a specific and sensitive technique for measuring 1113-

O H -A 4 in serum and FFL, the presence of this weakly androgenic steroid in the FFL of

women with normal and polycystic ovaries was established. Although concentrations of 1113-

O H -A 4 were higher in the circulation of women with PCO, FFL concentrations were lower

than in women with normal ovaries. III3-OH-A4 concentrations are therefore not a useful marker for this enigmatic condition.

VI. Discussion

GH studies - methodology.

Suboptimal responders.

The participants in the studies were women who, despite requiring large doses of exogenous gonadotrophins, had suboptimal responses to ovarian stimulation regimens. Women with "poor" responses in IVF-ET programmes are difficult to treat and have an unfavourable outcome (Pellicer et al 1987). Treatment options currently include progressively increasing the dose of hMG or FSH, desensitising the pituitary with GnRH analogues prior to hMG administration or, occasionally, offering oocyte collection in natural or clomiphene stimulated cycles (Serafini & Marrs 1988, Benadiva et al 1988).

Increasing the dose of hMG does not necessarily result in a proportional improvement in the ovarian response and a plateau of ovarian response is often reached. Clinically this presents a dilemma of management and alternative treatments are needed for this small group of women.

IGF-I augmentation of the FSH-primed granulosa cell response has been well documented (Adashi et al 1984, 1985b, 1985c) and Jacobs et al (1987, 1988) used these cell studies as a basis for the clinical application of biosynthetic GH in ovulation induction. The work presented in this thesis complements the in-vivo fertilisation studies (Homburg et al 1988, 1990a,b) and describes the first use of GH administration performed in the IVF-ET setting.

Follicular development.

The aim of ovulation induction in amenorrhoeic women is unifollicular development. In those women resistant to CC, follicular stimulation is best achieved with daily injections of exogenous gonadotrophins (or pulsatile GnRH infusions) which may take several weeks (Hamilton-Fairley et al 1991). In IVF-ET programmes the aims are different. Multifollicular development is obligatory and the duration of treatment tends to be shorter. The ultimate aim of ovarian stimulation, prior to IVF-ET, is the collection of the maximum number of mature

VI. Discussion

oocytes with the transfer of healthy embryos.

With this is mind a suboptimal response was arbitrarily defined, for the CC and hMG studies, as one in which 3 or fewer oocytes were collected or two or fewer embryos transferred. This suboptimal response occurred despite the patient receiving a starting dose of at least 4 ampoules of hMG per day. These entry criteria defined a particularly resistant sub-group of "poor responders" but this was expedient as GH treatment in IVF-ET was untried. Apart from ever increasing doses of hMG, however, at that time, there was little other treatment to offer.

The randomised study of GH co-treatment with CC and hMG did not demonstrate an impressive improvement in ovarian response and the entry criteria were subsequently relaxed for the buserelin and hMG study. The aim of the latter study was to assess the use of GH in women who had some follicular development, but where improvement in the ovarian response was required. The entry criteria were therefore expanded to include women who had had up to 6 oocytes collected but where fewer than 4 embryos had been transferred. I consider that, in the buserelin and hMG study, the women did not necessarily constitute a true group of "poor responders" as the entry criteria were quite generous. The inclusion criteria were, however, appropriate as, without GH, larger doses of hMG would have been required in the next treatment cycle.

Polycystic ovaries.

The specific characteristics of women who respond suboptimally are difficult to define and the women form a heterogeneous group. Some women are found to have raised gonadotrophin concentrations and are thus either perimenopausal or have the resistant ovary syndrome. Other diagnostic tests tend not to be helpful. The finding of a normal appearance on scanning the ovaries does not predict a normal response to ovarian stimulation.

A pretreatment ultrasound scan of the ovaries was performed on all of the women in these studies and 34 of the 50 women recruited had co-incidentally diagnosed PCO. The finding of such a high percentage of women with ultrasound diagnosed PCO amongst the poor

VI. Discussion

response group has not been reported in the literature. This figure does, however, correspond with two other studies demonstrating a high percentage of women with ultrasound diagnosed PCO in populations attending IVF-ET centres (Owen et al 1989, Rutherford et al

unpublished).

The women in the GH studies who were shown to have ultrasound diagnosed PCO did not have the classical signs and symptoms of PCO syndrome; most obviously they all had regular cycles. Hirsutism was not formally assessed but the group of women with PCO did not have higher BMIs or LH concentrations than the women with normal ovaries.

Women with PCO are typically regarded as potential hyper-responders and anxieties about ovarian hyperstimulation syndrome are axiomatic. That a high proportion of women with a previously suboptimal response have PCO reflects the heterogeneity of the latter condition. The wide range of ovarian response to gonadotrophins may reflect a diversity of action of some intraovarian modulator, for example the IGFs.

Study design.

Placebo controlled trial.

It was considered imperative that, having shown an improved ovarian response to GH in the open study, a placebo controlled study be initiated. Particularly in the emotive area of infertility, treatments can be introduced without suitable investigation or confirmation of efficacy. Within the setting of a private IVF-ET centre, financial motivation can easily lead to the introduction of unproven therapies.

After the initial open study was completed, it was made clear to the patients that GH was only available through the placebo controlled study. For ethical reasons, the design of the study included an open arm of GH treatment for women initially randomised to receive placebo. At least two cycles with no treatment were allowed to lapse before the GH cycle was undertaken.

VI. Discussion

Burger et al (1991) reported a reduced requirement for hMG in cycles following GH administration. The setting was an ovulation induction programme, however, and the women were amenorrhoeic and profoundly hypoestrogenic. The studies presented in this thesis do not address the phenomenon of a carry-over effect but I consider that women with normal hormone concentrations, undergoing ovarian stimulation prior to IVF-ET, form a fundamentally different group and a marked carry-over effect after two or more months is unlikely.

Age Criteria,

In both of the placebo controlled trials, there was an age restriction for entry. The women were less than 40 years in the CC and hMG studies and less than 38 years in the buserelin and hMG studies. The age exclusion criterion was changed for the second study as I aimed to recruit women with potentially more responsive ovaries. Perimenopausal women, defined herein as women with an early follicular phase serum concentration of FSH of greater than 15iu/L, were excluded from the placebo controlled studies, as 2 perimenopausal women had shown no response to GH in the open CC and hMG study.

Diagnostic Categories,

In the initial CC and hMG studies women whose partners had oligospermia were excluded. Since, however, the ovarian response to GH was considered the end point of the studies, not pregnancy rates, in the buserelin and hMG study women with any indication for IVF-ET were included. It had also been noted that the implantation rate, in the women with oligospermie partners achieving embryo replacement, was not different from the patients in the other diagnostic categories (Sharma et al 1988).

In the buserelin and hMG study there was a chance difference in the length of infertility between those women going on to receive GH and those receiving placebo. Since the end point of study was not fertility, but the effect of GH on the induction of multifollicular development with the collection of many oocytes, the difference was not, however, regarded as important in the design of the studies.