Intranasal peptide contraception by inhibition of ovulation with the gonadotropin-releasing hormone superagonist nafarelin: six months' clinical results

LHRH agonists and the prevention of breast and ovarian cancer

Early age at natural menopause or bilateral ovariectomy substantially reduce a woman's lifetime risk of breast cancer. Reversible 'bilateral ovariectomy' can now in effect be achieved by 'high-dose' luteinising hormone releasing hormone (LHRH) agonists (LHRHAs). The harmful effects of such medical reversible bilateral ovariectomy, in particular the increased risks of coronary heart disease and osteoporosis, can in all likelihood be obviated by 'low-dose' oestrogen replacement therapy (ERT), specifically 0.625 mg of conjugated equine oestrogens (CEE) for 21 days in each 28-day treatment cycle, and such ERT use will only negate to a relatively small extent the beneficial effect of such bilateral ovariectomy on breast cancer risk. We calculate that such an LHRHA plus low-dose ERT regimen given to a premenopausal woman for 10 years will, in addition to being a most effective contraceptive, decrease her lifetime risk of breast cancer by more than 50%. We calculate that such a 10-year regimen will also decrease her risk of ovarian cancer by two-thirds. This regimen should leave endometrial cancer risk and bone metabolism unaltered, and may reduce the risk of heart disease. The addition of a 'low-dose' progestogen to the regimen for 12 days in each 28-day treatment cycle would be beneficial to the endometrium, but it will adversely affect risk factors for heart disease and it may significantly reduce the benefit of the regimen as regards breast cancer. A satisfactory compromise may be to add a low-dose progestogen for 12 days at less frequent intervals. Another possibility may be to deliver a progestogen solely to the endometrium with an intra-uterine device; the benefits of such a regimen would be a significant reduction in the incidence of breast, ovarian and endometrial cancer.

Ovarian cyst formation: a complication of gonadotropin-releasing hormone agonist therapy

Since gonadotropin-releasing hormone (GnRH) analogs were introduced into clinical therapeutic use, several side effects directly related to the hypoestrogenic state have been reported. The authors have encountered a rather infrequent complication, namely ovarian cystic formations, when using these compounds for selected in vitro fertilization and embryo transfer (IVF-ET) cases. In 7 of 24 patients with Decapeptyl (D-Trp6-luteinizing hormone-releasing hormone [LH-RH], Ferring, Kiel, FRG) treatment, and in 5 of 22 patients treated with Buserelin (Superfact, Hoechst A.G., Frankfurt, FRG), solitary ovarian cysts developed during the down-regulation phase. Their growth did not change during ovulation induction with menotropins. Although the mechanism of ovarian cyst formation during GnRH agonist treatment is not clear, their presence does not appear to interfere with the fertility of these women.

Induction of ovulation with luprolide acetate and human menopausal gonadotropin

Four women with unexplained infertility and two anovulatory oligomenorrheic women who experienced repeated premature luteinization when treated with human menopausal gonadotropin (hMG) or gonadotropin-releasing hormone (GnRH) were given the gonadotropin-releasing hormone agonist (GnRHa), luprolide acetate, in order to effect medical hypophysectomy. This was followed by hMG for induction of ovulation. Four of the six patients had hMG-only cycles, which were compared with the luprolide acetate/hMG cycles. The luprolide acetate/hMG cycles resulted in normal folliculogenesis with presumptive ovulation. In luprolide/hMG cycles, significantly more hMG was needed for induction of ovulation than in hMG-only cycles. Premature luteinization was abolished with luprolide acetate treatment.

The theory and practice of ovulation induction with gonadotropin-releasing hormone

Gonadotropin-releasing hormone therapy has undergone sufficient basic and clinical investigation as a tool for ovulation induction that it should now be considered a safe and effective infertility therapy for office practice. Nevertheless, there remains sufficient mystique about patient selection, optimal dosage and route of delivery, and apprehension on the part of both physicians and patients about cost and inconvenience of medication pumps that gonadotropin-releasing hormone therapy has not enjoyed the widespread acceptance it deserves. This article presents straightforward guidelines for therapy that are based on a detailed review of current literature, together with new information about evolving pump technologic characteristics, that should offer reassurance to the practitioner considering use of gonadotropin-releasing hormone therapy in her/his practice.

Endometrial morphology after 6 months of continuous treatment with a new gonadotropin-releasing hormone superagonist for contraception

Light and electron microscopic studies were performed on endometrial curettage specimens from 27 women after 6 months of contraceptive treatment with continuous intranasal gonadotropin hormone-releasing hormone (GnRH) superagonist. The GnRH superagonist nafarelin acetate (D-Nal[2]6-GnRH) was used in single daily doses of 125 or 250 micrograms. Ovulation was inhibited during all but one of the 159 treatment months. No pregnancies occurred. In 6 women with fairly regular bleedings, the endometrium displayed weak to normal proliferation. Twenty women developed oligomenorrhea or amenorrhea, 16 of them had inactive endometrium, 1 had weakly proliferative endometrium, and 3 endometrial biopsies were too sparse for adequate evaluation. One woman reported repeated episodes of heavy uterine bleedings. The endometrial biopsy from this woman showed weak proliferation. No signs of endometrial hyperplasia were observed. Generally, the electron microscopy showed signs of low metabolic activity and weak protein synthesis. Thus, long-term continuous treatment with nafarelin acetate for inhibition of ovulation does not appear to have untoward effects on the endometrium.

Clinical applications of LHRH analogues

What is the current state of clinical application of inhibition of gonadal activity with LHRH agonists or antagonists? It seems unlikely in the short term that antagonists will be widely applied due to the short-acting nature of the present compounds and their troublesome side-effects. In contrast clinical studies with a number of agonists have demonstrated their efficacy in producing a hypogonadal state safely with rapid recovery following cessation of therapy. Although nasal administration may be suitable for short-term suppression (up to 28 days) it seems likely that long-acting depot preparations will be useful for more prolonged suppression. Perhaps the easiest application to determine will be the profound suppression required to produce medical castration in hormone-dependent tumours. The combination of agonist and receptor blocker is attractive particularly when the receptor blocker like cyproterone acetate also suppresses the release of LH, FSH and adrenocorticotrophic hormone. In cancer of the prostate and breast the side-effects due to inhibition of secretion of testosterone and oestradiol are tolerable although the only benefit over castration is the avoidance of minor surgery. The agonists should improve significantly the existing treatment for precocious puberty, endometriosis, uterine fibroids, polycystic ovary syndrome (PCO) and induction of ovulation although large scale trials comparing different therapies and doses are required. Finally, the concept of combination therapies to block further the influence of steroid hormones suggests challenging possibilities for even more effective therapy.