Clinical applications of LHRH and its analogues

Advances with androgen deprivation therapy for prostate cancer

INTRODUCTION

Androgen deprivation therapy (ADT) has been a treatment of choice for prostate cancer in almost all phases, particularly in the locally advanced, metastatic setting in both hormone-sensitive and castration-resistant diseaseand in those who are unfit for any local therapy. Different ways of administering ADT comes in the form of surgical or chemical castration with the use of gonadotropin-releasing hormone (GnRH-agonists) being the foremost way of delivering ADT.

AREAS COVERED

This review encompasses ADT history, use of leuprolide, degarelix, and relugolix, with contextual use of ADT in combination with androgen-signaling inhibitors and potential mechanisms of resistance. Novel approaches with regard to hormone therapy are also discussed.

EXPERT OPINION

The use of GnRH-agonists and GnRH-antagonists yields efficacy that is likely equivalent in resulting in testosterone suppression. While the side-effect profile with ADT are generally equivalent, effects on cardiovascular morbidity may be improved with the use of oral relugolix though this is noted with caution since the cardiovascular side-effects were a result of secondary subgroup analyses. The choice of ADT hinges upon cost, availability, ease of administration, and preference amongst physicians and patients alike.

Interaction Between Luteinizing Hormone-Releasing Hormone and GM1-Doped Cholesterol/Sphingomyelin Vesicles: A Spectroscopic Study

Understanding the role of neural membrane in translocation and action of neurohormone is of great importance. Luteinizing hormone-releasing hormone (LHRH) is a neuropeptide hormone and it acts as a final signaling molecule by stimulating the synthesis of LH and FSH to maintain reproduction in all vertebrates. The receptors of LHRH are found in breast tumors and pituitary gland in the brain. Moreover, neural plasma membrane is also found to contain specific binding site for LHRH. The mechanism by which LHRH binds to membrane before it binds to the receptors is a very critical step and can have a profound impact upon the translation of peptide across the membrane. A complex form of glycosphingolipids known as Ganglioside is an important component of plasma membrane of nerve cells and breast tumor tissues. They play an important role in various physiological membrane processes. Therefore, the interaction of ganglioside-containing membrane with LHRH might be crucial in aiding the LHRH to translate through the neural membrane and reach its receptor for binding and activation. Using CD, UV-Absorbance, and fluorescence spectroscopy, the effect of Ganglioside Monosialo 1(GM1)-induced conformational changes of LHRH in the presence of Cholesterol (CHOL)/Sphingomyelin (SM) and GM1/CHOL/SM vesicles was studied. The aforesaid spectroscopic studies show that LHRH is able to bind with both the vesicles, but GM1-containing vesicles interact more effectively than vesicles without GM1. CHOL/SM vesicles partially disturb the conformation of the peptide. Moreover, binding of LHRH to GM1/CHOL/SM vesicles induces loss of conformational rigidity and attainment of a random coil.

Gonadotropin releasing hormone agonists: Expanding vistas

Gonadotropin-releasing hormone (GnRH) agonists are derived from native GnRH by amino acid substitution which yields the agonist resistant to degradation and increases its half-life. The hypogonadotropic hypogonadal state produced by GnRH agonists has been often dubbed as "pseudomenopause" or "medical oophorectomy," which are both misnomers. GnRH analogues (GnRH-a) work by temporarily "switching off" the ovaries. Ovaries can be "switched off" for the therapy and therapeutic trial of many conditions which include but are not limited to subfertility, endometriosis, adenomyosis, uterine leiomyomas, precocious puberty, premenstrual dysphoric disorder, chronic pelvic pain, or the prevention of menstrual bleeding in special clinical situations. Rapidly expanding vistas of usage of GnRH agonists encompass use in sex reassignment of male to female transsexuals, management of final height in cases of congenital adrenal hyperplasia, and preserving ovarian function in women undergoing cytotoxic chemotherapy. Hypogonadic side effects caused by the use of GnRH agonists can be tackled with use of "add-back" therapy. Goserelin, leuprolide, and nafarelin are commonly used in clinical practice. GnRH-a have provided us a powerful therapeutic approach to the treatment of numerous conditions in reproductive medicine. Recent synthesis of GnRH antagonists with a better tolerability profile may open new avenues for both research and clinical applications. All stakeholders who are partners in women's healthcare need to join hands to spread awareness so that these drugs can be used to realize their full potential.

Will GNRH antagonists be worth the wait?

Gonadotropin-releasing hormone (GnRH) is also known as luteinizing hormone-releasing hormone (LHRH), formerly luteinizing hormone releasing factor (LRF). Since this hormone regulates the secretion of both FSH and LH, we prefer to call it GnRH. GnRH antagonists, as the name implies, are a class of compounds that actively compete with GnRH for the GnRH receptor, thereby neutralizing the effects of GnRH by competitive receptor occupancy. In order to fully appreciate their potential clinical utility, it is first important to comprehend the critical role of GnRH in the regulation of the pituitary-gonadal axis and secondly to familiarize ourselves with the mechanisms of action of GnRH, GnRH agonists and GnRH antagonists.

GnRH analogues in the treatment of fibroids

Uterine fibroids are estimated to affect up to 25% of women of reproductive age and are a common cause of morbidity, being associated with menstrual dysfunction, iron deficiency anaemia, pregnancy wastage and subfertility. Their pathogenesis remains unknown but their association with ovarian function and oestrogen production is undisputed and supported by their occurrence only after puberty and the shrinkage observed after the menopause. This oestrogen dependency has recently been exploited therapeutically through investigation of the use of agents that induce a hypo-oestrogenic state, the gonadotrophin-releasing hormone (GnRH) or luteinizing hormone-releasing hormone (LHRH) analogues.

Treatment with buserelin, an agonist of gonadotropin-releasing hormone, suppresses ovarian hyperstimulation syndrome induced in rabbits

Human menopausal gonadotropin (hMG, 75 IU/body/day) and a gonadotropin-releasing hormone (GnRH) agonist buserelin (1, 10, 100 microg/kg/day) were simultaneously administered to female rabbits by the subcutaneous route for 7 days, and the effects on organ weights, plasma hormones and weight of ascitic fluid were examined. Treatment with hMG increased the ovarian weight, plasma estradiol and weight of ascites, thus indicating that ovarian hyperstimulation syndrome had been induced. Simultaneous treatment with buserelin decreased the changes induced by hMG. GnRH agonists can thus be surmised to reduce the severity of ovarian hyperstimulation syndrome in the rabbit. However, caution is needed when extrapolating the results of this rabbit model to humans.

Suppression of puberty with long-acting goserelin (Zoladex-LA): effect on gonadotrophin response to GnRH in the first treatment cycle

BACKGROUND AND OBJECTIVES

Depot GnRH analogues are widely used in the treatment of precocious puberty, or suppression of relatively early puberty where growth or psychosocial well-being may be compromised. One example is Zoladex (Z goserelin 3.6 mg), which can be given every 4 weeks. This injection frequency may not always achieve adequate suppression of pubertal signs. A long-acting form, Zoladex-LA 10.8 mg, has now been introduced with a potential duration of action of 12 weeks. In order to assess the efficacy of Zoladex-LA in gonadotrophin suppression we have measured LH and FSH responses to GnRH at diagnosis and 8 and 12 weeks after injection in a group of children treated with Zoladex-LA for central precocious or early puberty.

METHODS

Forty-nine children (40 girls) with clinical evidence of central precocious puberty (CPP) or early puberty (EP) were started on Zoladex-LA, either de novo (n = 29) or on changing from Zoladex. Ages at diagnosis ranged from 1.7 to 10.6 years (median 7.8 years). Twenty-three had a structural cause with abnormality on magnetic resonance/computerized tomography (MR/CT) head scan, nine had a syndrome or nonspecific brain injury, and in 17 the cause was idiopathic.

RESULTS

At diagnosis, in the de novo group, median peak LH was 13.6 IU/l and median peak FSH was 12.0 IU/l. By 12 weeks gonadotrophins were suppressed to 0.9 and 0.8 IU/l, respectively. In the previously treated group, median peak LH at diagnosis was 12.8 IU/l and median peak FSH was 15.0 IU/l with suppression to 0.8 and 1.1 IU/l, respectively, at 12 weeks. In the latter group peak FSH was higher than peak LH at both 8 and 12 weeks (P < 0.05) and there was a significant rise in peak LH (P < 0.05) and FSH (P = 0.01) between 8 and 12 weeks. There was no correlation between age at diagnosis and peak LH or FSH at 8 or 12 weeks. Nevertheless, individual patients in both groups showed evidence of incomplete gonadotrophin suppression at 12 weeks.

CONCLUSION

Zoladex-LA induces a significant reduction in gonadotrophins over 12 weeks. However, there are individuals, particularly those previously on Zoladex, in whom gonadotrophin suppression is waning by 12 weeks. As found with Zoladex, some children with precocious puberty treated with Zoladex-LA may require increased injection frequency, although correlation with clinical evidence of suppression needs to be studied further.

Design of triptorelin loaded nanospheres for transdermal iontophoretic administration

Triptorelin is a decapeptide analog of luteinizing hormone releasing hormone, currently used for the treatment of sex-hormones dependents diseases. The aim of this work was to prepare triptorelin-loaded nanospheres useful for transdermal iontophoretic administration. Nanospheres were prepared with the double emulsion/solvent evaporation technique. The effect of three parameters on the encapsulation efficiency has been determined: the role of the pH of the internal and external aqueous phases, the nature of the organic solvent and the effect of three different poly(lactide-co-glycolide) (PLGA) co-polymers. Particle size, zeta potential and release kinetics were also determined. The encapsulation efficiency varied from 4 to 83% reaching the maximum value when both the internal and the external water phases were brought to pH 7 (isoelectric point of the peptide), methylene chloride was used as solvent of the copolymers and PLGA rich in free carboxylic groups was employed. The release profiles obtained with this co-polymer were characterized by the absence of burst effect. This behavior as well as the high encapsulation efficiency was explained by an ionic interaction occurring between the peptide and the co-polymer. This supports the already expressed theory that the release of peptides and proteins from PLGA nanospheres is also governed by the affinity of the encapsulated molecule versus the polymer. The obtained nanoparticles, regarding their size, amount encapsulated and zeta potential, were shown to be suitable for transdermal iontophoretic administration.

Should we still advise infertile couples to use (barrier) contraception before IVF down-regulation?

OBJECTIVE

To determine the outcome of spontaneous conceptions in women who received GnRH agonists during mid-luteal phase down-regulation before IVF treatment.

DESIGN

Retrospective analysis of case records and study of the literature.

SETTING

Two university-affiliated reproductive medicine units.

PATIENT(S)

Seventy-three women who conceived spontaneously after starting down-regulation with a GnRH agonist before controlled ovarian hyperstimulation.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Course and clinical outcome of pregnancies.

RESULT(S)

Seventy-four pregnancies occurred in 73 women who received a GnRH agonist. Of these patients, 6 (8%) had a biochemical pregnancy, 6 (8%) had an ectopic pregnancy, 21 (28%) miscarried, and 41 pregnancies resulted in successfully delivered babies; there were 2 cases of congenital abnormalities.

CONCLUSION(S)

These cases, together with other published data, suggest that pregnancy outcome is not adversely affected by exposure to GnRH agonist during luteal-phase down-regulation. A central register of pregnant women who received a GnRH agonist is needed.

Management of women with polycystic ovary syndrome who experienced premature luteinization during clomiphene citrate treatment

OBJECTIVE

To determine the preferred treatment modality in patients with PCOS who experienced premature luteinization during CC treatment.

DESIGN

Prospective randomized study.

SETTING

Tertiary medical center.

PATIENTS

Twenty-two infertile women with PCOS demonstrating premature luteinization during at least two consecutive CC cycles.

INTERVENTIONS

Randomized induction of ovulation either with FSH alone or with GnRH agonist combined with FSH for a single treatment cycle.

MAIN OUTCOME MEASURES

Premature luteinization was defined as serum progesterone >1.5 ng/mL before hCG administration.

RESULTS

Premature luteinization occurred in eight of the 10 patients (80%) in group A and in two of the 12 patients in group B (16.6%). This result corresponds to the higher mean (+/-SD) progesterone level present in group A patients as compared to those in group B (2.0 +/- 1.2 ng/mL vs. 1.2 +/- 0.6 ng/mL, P=0.03). No pregnancies were achieved in group A, whereas the pregnancy rate per cycle observed in group B was 33.3% (4/12). On the day of hCG administration, the maximum mean (+/-SD) estradiol level was significantly lower (P<0.0001) in group A (210.6 +/- 37.9 pg/mL) than in group B (600.3 +/- 253.8 pg/mL). The treatment duration and the number of FSH ampules used did not differ between the groups.

CONCLUSIONS

Pituitary desensitization with GnRH analog in combination with FSH is superior to FSH-only treatment in PCOS patients who demonstrate premature luteinization during CC treatment.

Protective effect of leuprolide acetate on 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary carcinogenesis in rats

The anti-carcinogenic effect of TAP-144-SR biodegradable microcapsules of copoly (DL-lactic/glycolic acid) copolymer containing a potent LHRH agonist, TAP-144 (D-Leu6-(des-Gly10-NH2)-LHRH ethylamide, leuprolide acetate) was investigated in 7,12-dimethylbenz(a)anthracene (DMBA)-induced rat mammary tumours. At 50 days of age, all rats were given 20 mg doses of DMBA by gastric intubation. Rats on the Initiation Group were given a single s.c. injection of TAP-144-SR (3 mg/kg) 1 week before DMBA treatment, and rats in the Promotion Group were given repeated s.c. injections every fourth week from 1 week after DMBA treatment until the end of the experiment. In the Initiation Group, tumour incidence and multiplicity were reduced to 20.8% and 15.0% of the Control Group values, respectively. In the Promotion Group, tumour incidence and multiplicity were also reduced to 17.7% and 7.9%, respectively. It was suggested that TAP-144-SR may be a potential candidate as an agent for hormonal chemoprevention in breast cancer.

S- and C-glycopeptide derivatives of an LH-RH agonist

The S- and C-glycosylated nonapeptides 1 and 2 were synthesized as analogs of the non-glycosylated LH-RH agonist buserelin (pGlu-His-Trp-Ser-Tyr-D-Ser(tBu)-Leu-Arg-Pro-NHEt) by segment condensation in solution. 1 and 2 differ from this peptide in the amino acid in position 6. In the first case (1), D-serine (tBu) is substituted by D-cysteine carrying a rhamnosyl residue, in the second case (2) D-alanine carrying a galactosyl moiety bound as C-glycoside is incorporated. The bioactivity of both glycopeptides as fertility drugs was determined from the dose dependent LH release in male rats. Additionally, in female rats the ovulation rate was assessed. As a result the analog 1 exhibits a similar biological activity as buserelin while analog 2 shows about 25% of this potency. Compared to buserelin the solubility of the analogs 1 and 2 in aqueous buffer is improved by more than two orders of magnitude due to the carbohydrate moieties.

Bone loss during gonadotropin releasing hormone agonist treatment and use of nasal calcitonin

Gonadotropin releasing hormone (GnRH) agonists have shown to be effective in the treatment of several sex-hormone-dependent conditions. However, their use could be limited by the bone loss they induce. To evaluate the use of nasal salmon calcitonin (sCT) in preventing this bone loss, 40 patients with endometriosis were treated for 6 months with triptoreline (3.75 mg monthly) and calcium (1 g daily), and randomized in three groups-placebo, sCT 100 IU daily and sCT 200 IU daily-in a prospective double-masked study. Dual-energy X-ray absorptiometry and biochemical parameters were used to evaluate the benefit of the treatment. At baseline, there were no statistically significant differences between the groups. After 6 months, estradiol and biochemical markers of bone metabolism were at postmenopausal levels, with no difference between the groups. There was no difference in bone loss in the three groups, at all sites. Mean lumbar bone loss was 4.01 +/- 2.59% (mean +/- SD) in this population. In this study dosages of 100 IU and 200 IU daily of nasal sCT were insufficient to prevent bone loss during GnRH agonist treatment.

Kinetic analysis of prostatic volume in patients with stage D prostatic cancer treated with LHRH analogues in relation to prognosis

OBJECTIVE

To evaluate the clinical usefulness of the kinetic analysis of prostatic volume in the prognosis of patients with Stage D prostatic cancer treated using luteinizing hormone-releasing hormone (LHRH) analogues.

PATIENTS AND METHODS

The reduction of prostatic volume was monitored in 12 patients with Stage D prostatic cancer using transrectal ultrasonography (TRUS) after treatment with LHRH analogues. Data obtained from the kinetic analysis of prostatic volume were compared with the prognosis.

RESULTS

All the patients having a reduction time, tau (derived from the kinetic analysis of prostatic volume change with time), of less than 41 days had neither clinical progression within 15 months nor death caused by prostatic cancer during the 5-year follow-up, while the disease-specific 5-year survival rate in patients having a tau of greater than 42 days was as low as 17%. The difference in both the progression and disease-specific survival between these groups was statistically significant (P < 0.05) despite the limited number of patients. In contrast, conventional prognostic parameters showed no significant predictability for prognosis with the exception of prostatic acid phosphatase, which correlated strongly with the occurrence of progression within 15 months.

CONCLUSION

The kinetic analysis of the change of prostatic volume using TRUS shows promise in the prognosis of the patients with Stage D prostatic cancer.

Gn-RH agonists in the treatment of prostatic carcinoma

About 80% of advanced prostate cancers are hormone dependent. Androgen withdrawal by either surgical castration or medical castration is the first-line treatment for this disease. As the patient's choice and quality of life are now being taken into account, reversible medical castration with GnRH analogues has emerged as a new palliative treatment. The use of these compounds alone or in combination with anti-androgens and the timing of initiating the hormone therapy were reviewed. Unfortunately, relapses after androgen ablation occur in most patients, as their cancer becomes insensitive to androgens. Management of hormonal refractory cancer remains a challenge to clinicians. No clinical trial using promising new therapeutic approaches such as GnRH antagonists, GnRH analogues linked to cytotoxic radicals, or a combination of GnRH analogues with somatostatin analogues or bombesin/GRP antagonists have been published until now.

Prostate cancer

Prostate cancer is the most common noncutaneous malignancy diagnosed in American men, and in 1994 it will pass lung cancer as the most common cancer diagnosed in the United States, with an estimated 200,000 new cases. The molecular biology of prostate carcinogenesis is rapidly advancing, and it is clear that, to a degree, prostate cancer is a heritable disease. The use of serum prostate-specific antigen (PSA) as a screening tool has been widely accepted by the medical community, although the evidence to support the efficacy of screening is not yet available. The curative approaches to organ-confined, clinically localized prostate cancer include radiation therapy, radical prostatectomy, and close observation in selected patients. The absence of well-designed clinical trials contributes to the confusion surrounding which curative treatment is the best option in individual patients. The standard approach to patients with evidence of extracapsular spread without distant metastases has been external-beam radiotherapy, although the results with radiation therapy alone in these patients has left considerable room for improvement. Innovative combined-modality approaches are currently being investigated at a number of institutions for these poor-prognosis patients. Three-dimensional conformal radiation therapy is currently being investigated at multiple institutions and offers some hope for improved results. The treatment of metastatic disease remains hormonal manipulation, although the exact nature of optimal androgen deprivation is currently a matter of considerable debate. In patients with hormone-refractory disease newer regimens using novel chemotherapy regimens offer some promise.

Effects of the luteinizing-hormone-releasing hormone (LHRH) antagonist ramorelix (hoe013) and the LHRH agonist buserelin on dimethylbenz[]anthracene-induced mammary carcinoma: studies with slow-release formulations

Luteinizing-hormone-releasing hormone (LHRH) agonists and antagonists are antigonadotropic agents for reversible ovarian/testicular suppression in gynaecology and in oncology. Pituitary inhibition and suppression of the gonadal steroids can be maintained with continuous release rates from biodegradable implants or microparticles. The effects of curative and preventive treatment with slow-release formulations of the LHRH agonist buserelin (implants and microparticles) and the LHRH antagonist ramorelix (hoe013) (microparticles) on dimethylbenz[a]anthracene(DMBA)-induced mammary tumours in rats and the pharmacokinetics of these formulations are described. In addition, direct effects of the LHRH antagonist ramorelix on tumour growth were studied. The release rates of the implants (polylactide-glycolide 75:25) and the microparticles (polylactide-glycolide 50:50) were calculated from urinary excretion of the peptides. The curative treatment started at the time of full tumour development (76 days after DMBA induction). A single buserelin implant injection (3.3 mg peptide) resulted in a dramatic tumour regression within 14 days, which was comparable to ovariectomy. It prevented tumour progression for 120 days. Previous studies in rats have shown that ramorelix microparticles (3.6 mg peptide) have a shorter duration of action (about 14 days) in suppression of gonadal function when compared to buserelin microparticles (3.6 mg peptide), where the suppression lasted for about 35 days. As expected, a single injection of ramorelix microparticles (3.6 mg peptide) inhibited tumour progression for only 14 days. This short action is due to a different release profile of the ramorelix microparticles and the different specific activities of peptides incorporated. In the preventive experiments animals were treated 17 days after DMBA induction before tumour development. Treatment with buserelin implants (3.3 mg peptide) every 56 days or with buserelin microparticles (3.6 mg peptide) every 28 days and the treatment with ramorelix microparticles (1.8 mg peptide) every 7 days prevented the development of tumours. Six weeks after the last injection of ramorelix microparticles a strong tumour progression was seen. There was a clear correlation between peptide release and tumour inhibition. The implants and the microparticles were well tolerated, no tissue reaction or side-effects of ramorelix were seen. Treatment of ovariectomized oestradiol-substituted DMBA-treated rats resulted in a marginal (not significant) inhibition in tumour development. LHRH antagonists in slow-release formulations (microparticles or implants) represent a new approach in treatment of hormone-dependent tumours because of the immediate onset of gonadal function and the increased drug efficacy due to the controlled release from biodegradable microparticles.

Evolving role of Gonadotropin-Releasing Hormone antagonists

GnRH antagonists, unlike GnRH agonists, do not act via "downregulation." Instead, GnRH antagonists monopolize the GnRH receptors to such an extent that endogenous GnRH is unable to bind to sufficient numbers of GnRH receptors to provoke release of LH/FSH. This fundamental difference in the mechanism of action of GnRH antagonists versus GnRH agonists is anticipated to result in clinical benefits for certain applications.

Properties of a potent LHRH antagonist (Org 30850) in female and male rats

Org 30850 (Ac-D-pClPhe1,2,D-Bal3,D-Lys6,D-Ala10-LHRH) is a novel LHRH antagonist, which is being developed for the treatment of hormone-dependent disorders. The activities of this compound with respect to its endocrinological properties and side-effects were tested in rats and the results were compared with one of the first LHRH antagonists: Ac-D-pClPhe1,2,D-Trp3,D-Arg6,D-Ala10-LHRH (Org 30276). A single subcutaneous (s.c.) dose of 0.3 micrograms/kg Org 30850 administered to rats in pro-estrus gave inhibition of ovulation in approx. 50% of the rats, whereas Org 30276 was approx. 4 times less potent. The effect of a single s.c. injection of Org 30850 on testosterone levels in young adult male rats was also studied. The administration of 250 micrograms/kg or higher of Org 30850 induced a significant decrease in testosterone levels after 3 h, this effect lasted for at least 48 h. Treatment of female rats for 14 days with a daily dose of 12 micrograms/kg Org 30850 decreased statistically significantly uterine and ovarian weights. At a daily dose of 50 micrograms/kg Org 30850 completely suppressed estrous cycles and significantly decreased estradiol and FSH serum levels. The LH levels were below the detection level in both control and treated animals on the (expected) second day of di-estrus. Treatment of male rats for 14 days (25-200 micrograms/kg) resulted in a dose-dependent reduction of the gonads, accessory sex organs, testosterone levels and gonadotrophins. The decrease in gonadal function in both sexes was reversible since the females proved to be as fertile as the controls 6 weeks after the last treatment and an almost complete recovery of the weight of testes, seminal vesicles and ventral prostate was observed in the males 4 weeks after cessation of treatment. In contrast to Org 30276, Org 30850 exerted very slight irritation at the site of injection and no edematous reactions in the extremities at a daily dose of up to 8 mg/kg in male rats. It is concluded that Org 30850 is a very potent LHRH antagonist without edematous reactions and with a more favourable therapeutic index than Org 30276.

An open randomized comparative study of the effect of goserelin depot and danazol in the treatment of endometriosis. Zoladex Endometriosis Study Team

OBJECTIVE

To compare the efficacy and safety of goserelin depot and danazol for endometriosis.

DESIGN

Open, randomized comparative trial.

SETTING

Multicenter European academic clinical institutions.

PATIENTS

A total of 307 patients with laparoscopically diagnosed endometriosis were randomized to goserelin (n = 204) or danazol (n = 103); 249 patients underwent second look laparoscopy (175 received goserelin and 74 danazol) and were analyzed for efficacy.

INTERVENTIONS

A 3.6-mg depot of goserelin monthly subcutaneously or oral danazol 200 mg three times a day administered for 24 weeks.

MAIN OUTCOME MEASURES

Efficacy assessments were based on changes in visible deposits at laparoscopy before and after treatment and subjective symptom scores at 4-week intervals during treatment and 8-week intervals after treatment for up to 24 weeks. Safety was assessed by adverse event reporting and clinical laboratory measures.

RESULTS

There were similar proportions of symptomatic (73%) and asymptomatic (but infertile) (27%) and comparable distribution of different severity of endometriosis randomized to each treatment. Significantly fewer patients randomized to goserelin (6.4%) withdrew during treatment compared with 20.4% randomized to danazol (P less than 0.05). There were significantly reduced visible deposits of endometriosis found post-treatment (P less than 0.0001) within each group but no differences between the treatments. The mean total subjective symptoms scores remained significantly less than entry at 24 weeks post-treatment (P less than 0.05). Hypoestrogenic side effects were more common in those receiving goserelin, particularly hot flushes, but anabolic/androgenic side effects of weight gain and muscle cramps were more common in those receiving danazol.

CONCLUSIONS

The monthly administered 3.6-mg depot preparation of goserelin was highly effective at inducing resolution of endometriotic implants and relieving the symptoms of endometriosis with prevention of their return during 24 weeks follow-up in the majority of patients. However, results were not significantly different from those achieved with danazol 600 mg/d.

The gonadotropin-releasing hormone (GnRH) agonist-induced initial rise of bioactive LH and testosterone can be blunted in a dose-dependent manner by GnRH antagonist in the non-human primate

Gonadotropin-releasing hormone (GnRH) agonists induce a clinically undesirable, transitory but very pronounced initial rise of gonadotropin and gonadal steroid secretion. We investigated, in a non-human primate model, whether the initial stimulatory effects of GnRH agonists can be avoided by a short period of pretreatment and simultaneous treatment with a GnRH antagonist. Three groups of five adult male cynomolgus monkeys (Macaca fascicularis) received a single s.c. biodegradable implant loaded with the GnRH agonist, buserelin ([D-Ser(TBu)6-desGly-NH2]-GnRH), releasing approximately 50 micrograms buserelin daily. From 1 week before to 1 week after inception of administration of GnRH agonist, group 1 received the GnRH antagonist vehicle, and groups 2 and 3 were given s.c. injections of the GnRH antagonist Nal-Glu ([Ac-D-Nal(2)1,D-4-Cl-Phe2,D-Pal3,D-Arg5,D-Glu6(AA),D- Ala10]-GnRH) at a dose of 450 or 2250 micrograms/kg daily. In the absence of GnRH antagonist, the GnRH agonist induced a marked elevation of serum luteinizing hormone (LH) and testosterone lasting for 2 and 5 days, respectively. In group 2, Nal-Glu reduced basal hormone secretion and delayed the peak of GnRH-agonist-induced hormone secretion by 1 day. In group 3, the GnRH-agonist-induced rise of LH and testosterone was prevented in three animals and did not exceed baseline hormone levels in the other two animals. Areas under the LH and testosterone curves were significantly reduced in group 3 compared to group 1. After withdrawal of the GnRH antagonist, a second transient rise of hormone secretion was observed. Except for testosterone in group 2, this rise did not exceed the baseline range of hormone concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Treatment of estrogen-dependent gynecological disorders with the gonadotropin releasing hormone agonist buserelin

The authors examined the effect and tolerability of buserelin in 40 women with endometriosis and ten women with uterine leiomyoma. Buserelin was given intranasally, 200 micrograms three times a day for 6 months. Laparoscopy was performed before and after, and ultrasonography during the treatment. Hormone and lipid profiles and other biochemical tests were run during the treatment. The bone mineral density was tested by dual photon absorptiometry before and after therapy in a group of patients. Although most of the patients complained of hot flushes, no women dropped out. AFS mean pelvic score decreased from 24.10 to 6.95 and the size of the fibroids decreased by 69% at the end of 6 months of treatment. In conclusion, our data suggest that the use of GnRH agonist has a place in the treatment of endometriosis and uterine leiomyoma but further studies are needed to conclude that buserelin given intranasally at a dose of 600 micrograms/day for 6 months is an alternative to other conventional medical treatment modalities in terms of pregnancy and recurrence rates.

The relation between pharmacokinetics and endocrine effects of buserelin implants in patients with mastalgia

Six patients with mastalgia were treated with polylactide/glycolide 50:50 implants containing 6.6 mg buserelin once every 4 weeks, to study the relationship between buserelin pharmacokinetics and suppression of pituitary-ovarian function. On the first treatment day there was an initial rise in plasma and urinary buserelin levels followed by a rapid fall during the next 2 days. After a plateau phase (60-80 micrograms/g creatinine) urinary buserelin/creatinine ratios decreased slowly to a mean value of 25 micrograms/g creatinine 4 weeks after implantation. Plasma oestradiol concentrations dropped to castrate values within 2 weeks of treatment reaching a mean concentration of 17 pmol/l compared to 27 pmol/l (P less than 0.01) determined in 680 postmenopausal control women. After the last implant injection urinary buserelin/creatinine ratios remained relatively high (greater than 5 micrograms/g creatinine) during more than 8 weeks followed by an exponential decrease (half-life of buserelin release: 15 days) to undetectable buserelin levels at 16-22 weeks after the last implantation. A rise of suppressed plasma oestradiol concentrations to above castrate levels was found 15-20 weeks after the last buserelin implantation, at a time when urinary buserelin excretion had decreased below 0.2 micrograms/g creatinine. It is concluded that after initial suppression of pituitary-ovarian function only very low concentrations of buserelin are needed to maintain suppression of ovarian activity by using slow release preparations.

Endocrine treatment of benign prostatic hypertrophy: current concepts

To summarize the endocrine approach for the treatment of BPH: much clinical data have accumulated over the past forty years. Until recently, scientists and physicians mainly concentrated on the reduction of androgens as a possible solution. We have come a long way from surgical castration, through the administration of hormones such as estrogen and progesterone, gonadotropin-releasing hormone agonists to the inhibition of an enzymatic reaction reducing testosterone to DHT--the now recognized active intracellular androgen metabolite. Recently, the role of estrogens has been emphasized with the finding that stromal hyperplasia is the main change occurring in BPH. Lately, research has been initiated to examine the clinical effect aromatase inhibitors would have in the treatment of human BPH. Since there is enough evidence that both the epithelial and stromal components of the human prostate undergo hyperplasia in BPH, and individuals vary with respect to their relative epithelial/stromal components, both structures would have to be reduced for therapy to be successful. Therefore, the combination of an antiandrogenic and antiestrogenic effect is theoretically promising. Indeed, prostates of beagles shrunken after treatment with an aromatase inhibitor, further decreased in weight after additional treatment with cyproterone acetate, an antiandrogen. We are now approaching the stage where these "antihormones" are both enzyme inhibitors with actually no side effects that preclude the use of the earlier generation's "antihormonal" hormonal drugs. Furthermore, it has recently been reported that the aromatase inhibitor, 4-hydroxy-androstenedione also inhibits human prostatic 5-alpha reductase, at least in vitro. The in vivo relevance of this finding awaits further classification. Thus, a good hormonal treatment that will be both scientifically sound, and clinically safe and effective, seems feasible in the near future. Two main factors have encouraged our interest and research into methods of inhibiting prostatic growth or reducing its obstructive symptomatology: the enormous cost of prostatic operations for outlet obstruction secondary to BPH, and the natural aging process of the population accompanied by deteriorated health precluding anesthesia and prostatic surgery. Medical treatment of BPH has to result in symptomatic improvement, elimination of residual urine, and improvement of flow to be considered successful. These are usually accomplished by surgery and results at least as good as those obtained by operation should be aimed at, if medical treatment is to replace surgery. Although indications for surgery and outcome of operations are well-defined, this is not the case when alternatives to prostatectomy are chosen.(ABSTRACT TRUNCATED AT 400 WORDS)

A dose-comparative endocrine-clinical study of leuprorelin in premenopausal breast cancer patients

Twelve premenopausal patients with advanced breast cancer were randomised to receive 3.75 or 7.5 mg of a slow release formulation of the luteinising hormone releasing hormone agonist leuprorelin once every 4 weeks. All patients were oestrogen receptor positive or unknown. Serum levels of gonadotrophins and oestrogens were suppressed markedly by both doses. All oestrogen values during treatment were within the postmenopausal range except for a single oestradiol level (274 pmol l-1) in one patient on the lower dose. There was no other indication that this lower dose was less effective as an oestrogen suppressant. There were two objective responders to the 3.75 mg dose and three to the 7.5 mg dose. Toxicity was confined almost entirely to hot flushes which occurred in 11/12 patients. We conclude that the slow release formulation of leuprorelin is effective in breast cancer treatment and that there is no major detriment to the use of the 3.75 rather than 7.5 mg dose.

Hormonal therapy of prostatic carcinoma. Defining the challenge

Prostate cancer is the most common neoplasm in the American male. More than 50% of patients present with locally advanced or metastatic disease and are not curable with local therapies such as radical prostatectomy or radiation therapy. This cancer is hormonally dependent, and methods that interrupt the hypothalamus-pituitary-testicular axis have been used to treat and control the disease effectively. The role of neutralizing the adrenal androgens is controversial. Combined androgen blockade refers to treatment modalities that lower circulating serum testosterone such as bilateral orchiectomy or an LH-RH agonist and combining it with an antiandrogen. The issue at hand is to review current clinical trials addressing the concept of combined androgen blockade and to determine the feasibility of a meta-analysis.

Basic and clinical aspects of GnRH-agonists in reproduction

Within recent years GnRH agonists have gained increasing importance in the treatment of reproductive failure. Their use as a pretreatment for in vitro fertilization increases the pregnancy rate at least under certain conditions. In cases of endometriosis and uterus myomatosus, GnRH agonists achieve high remission rates and may avoid or at least postpone the need for surgical intervention. The physiological basis and current clinical strategies are discussed.

Luteinizing hormone-releasing hormone analogue (Buserelin) treatment for central precocious puberty: a multi-centre trial

A multi-centre open trial of Buserelin, a luteinizing hormone-releasing hormone (LHRH) analogue, was conducted in 13 children with central precocious puberty. Eleven children (eight girls and three boys), aged 3.4-10.2 years at commencement, completed the required 12 month period of treatment. Initially all patients received the drug by intranasal spray in a dose of 1200 micrograms/day, but by the end of the 12 month period two were having daily subcutaneous injections and three were receiving an increased dose intranasally. The first month of treatment was associated in one boy with increased aggression and masturbation, and in the girls with an increase in the prevalence of vaginal bleeding. Thereafter, however, both behavioural abnormalities and menstruation were suppressed. Median bone age increased significantly during the study, but without any significant change in the ratio of height age to bone age. The median predicted adult height for the group therefore did not alter significantly over the twelve months of the study. Buserelin treatment caused a reduction in the peak luteinizing hormone and follicle-stimulating hormone (FSH) responses to LHRH, mostly to prepubertal levels, and also suppressed basal FSH. In the first weeks of treatment, the girls' serum oestradiol levels rose significantly and then fell to prepubertal or early pubertal levels. A similar pattern was seen for serum testosterone levels. Serum somatomedin-C levels, however, showed little fluctuation over the course of the study. Buserelin treatment was safe and well accepted, and offers the promise of improved linear growth potential in precocious puberty.

Human pharmacokinetic and pharmacodynamic profiles of leuprorelin acetate depot in prostatic cancer patients

A total of 21 patients with advanced prostatic cancer and one patient with benign prostatic hypertrophy received 3.75, 7.5 or 15 mg leuprorelin acetate depot subcutaneously. Serum leuprorelin concentrations increased immediately after injection, reaching a peak concentration (range 13.1-54.5 ng/ml), which was directly proportional to dose, within 3 h. Mean drug levels subsequently declined to a plateau directly proportional to dose at 5 weeks. There was also a significant (P less than 0.01) dose-dependent increase in the area under the concentration-time curve for 0-35 days. Serum concentrations of luteinizing hormone and follicle stimulating hormone rose initially with all doses, followed by a rise in serum testosterone and dihydrotestosterone concentrations, which then fell sharply, within 3 weeks. A reduced level of follicle stimulating hormone subsequently occurred in all 20 evaluable patients and was maintained in 17 patients over 5 weeks. There was also marked initial suppression of luteinizing hormone levels in 15 patients and in 13 this continued. Castration levels of testosterone and dihydrotestosterone were maintained in all patients for up to 5 weeks. In two patients there was a complete response, in 14 a partial response and in three stable disease, with no significant differences in relation to dose. Clinical improvement and serum hormonal changes suggest that leuprorelin acetate depot is effective at a dose as low as 3.75 mg when given once every 4 weeks.

Evidence for testicular impairment after long-term treatment with a luteinizing hormone-releasing hormone agonist in elderly men

Testicular responsiveness to 5,000 IU of human chorionic gonadotropin was evaluated in 14 patients with prostate cancer who were being treated with a slow-release luteinizing hormone-releasing hormone agonist for a median of 21 months. Serum testosterone response to human chorionic gonadotropin was markedly reduced in most patients, with the median level increasing from 0.25 to 1.65 nmol. per l. A second human chorionic gonadotropin test was repeated later in 5 patients who had been off treatment for a median of 6 months. Median serum testosterone levels increased to a maximum of 2.6 nmol. per l. compared to 28.2 nmol. per l. in an age-matched control group (p equals 0.008). Therefore, we conclude that long-term treatment with luteinizing hormone-releasing hormone agonists in elderly men leads to gonadal impairment that may not be as reversible as generally suggested.

[Treatment of precocious puberty with an LH-RH agonist (D-TRP6-LH-RH)]

Chronic administration of luteinizing hormone-releasing hormone (LH-RH) is currently considered as the most appropriate therapy of precocious puberty. A delayed release preparation of D-Trp-6-LH-RH (Décapeptyl in microcapsules) designed to release the agonist for 28 days after intramuscular injection of 60 micrograms/kg body wt was given to 12 boys and 26 girls with precocious puberty. Plasma levels of gonadotropins and sex steroids were suppressed to prepubertal levels within 3 weeks, whilst pituitary responses to LH-RH test were almost abolished within 7 weeks. A significant improvement of secondary sex characteristics, as well as gonadal size, was observed within 6 months. Growth velocity (cm/yr, mean +/- SD) was reduced in boys and girls from 9.9 +/- 3.4 and 9.6 +/- 3.3 respectively before treatment to 5.2 +/- 1.0 and 5.3 +/- 1.3 respectively during the third year of treatment. The mean ratio height age/bone age was just before treatment 0.91 in boys and 0.88 in girls and increased to 1 after 3 yr of treatment. This study shows that Décapeptyl in microcapsules induced a prolonged suppression of gonadal function and a relative blockade of bone maturation. A significant improvement of adult height relative to the effect of conventional treatments should be expected.

Fibroids and menorrhagia

Fibroids are an important cause of menorrhagia, resistant to conventional methods of medical treatment. The mechanism of their effect on menstrual blood loss is poorly understood but may involve abnormalities of local venous drainage, enlargement of the uterine cavity and abnormalities in prostaglandin production. Their cause remains unknown although it has long been assumed that they are oestrogen-dependent. In the past, study of their aetiology, prevention and treatment has received scant attention. Recent developments including measurement of tissue receptors for steroids and growth factors, non-invasive methods of monitoring fibroid growth and the use of LHRH agonists have enabled further study of their nature and of their response to therapy although much work remains to be done. The majority of women with uterine fibroids associated with menorrhagia are treated by hysterectomy although developments in endoscopic surgery have enabled a more conservative approach in some circumstances. LHRH agonists are the only medical agents which cause substantial shrinkage of fibroids although regression is not permanent. These agents are of value in short-term relief of symptoms and are likely to be a useful adjunct to surgery by reducing both uterine volume and bloodflow. However, because of the consequences of prolonged ovarian suppression, they are not suitable for long-term use unless there are medical contraindications to surgery. It remains to be seen whether their use in low-dose regimens or in combination with other agents will provide a successful, safe and cost-effective alternative to hysterectomy in women whose primary problem is heavy menstrual loss. They do however offer a means of conserving reproductive function in women wishing to retain this option.

Treatment of complicated benign prostatic hyperplasia with LHRH-analogues in aged patients

The effect of administration of an LHRH-analogue (LHRH-a) was evaluated in 11 patients with benign prostatic hyperplasia (BPH) in whom there were contraindications for surgery. These patients, who already had impaired potency due to age or serious illness, were given 1500 micrograms LHRH-a in the first week and 1200 micrograms from the eighth day onwards. They all improved significantly (P less than 0.001) with regard to their urological symptoms on day 60 of treatment. Our results demonstrate the influence of androgen in maintaining established BPH, the effectiveness of LHRH-a therapy in selected patients with BPH and the usefulness of a salivary testosterone assay for the follow-up of treatments expected to lower the bioavailability of androgen to target tissues.

Responsiveness of the hamster pancreatic cancer to treatment with microcapsules of D-Trp-6-LH-RH and somatostatin analog RC-160. Histological evidence of improvement

The effect of treatment with D-Trp-6-LH-RH, an agonist of luteinizing hormone-releasing hormone (LHRH), and somatostatin analog RC-160 was studied in male Syrian hamsters with N-nitrosobis(2-oxopropyl)amine (BOP)-induced pancreatic carcinoma. The peptides were administered periodically in long-acting microcapsule formulations designed to release controlled doses and maintain continuous blood levels of these analogs. The treatment lasted 60 d. Eighteen wk after administration of BOP, 80% of the animals developed ductal pancreatic adenocarcinomas, typically in multinodular form. Treatment with D-Trp-6-LH-RH resulted in a significant decrease in the tumorous pancreatic weight, and, in 35% of the specimens, changes indicative of histological regression were seen. Similarly, regressive alterations in the tumorous epithelium could be observed in 28% of the tumors in the RC-160 treated group. This regression was not accompanied by accumulation of lymphoid cells and only the epithelial components of the tumors were involved. These data indicate that the analogs D-Trp-6-LH-RH and RC-160 exert antitumoral effects on the experimentally-induced pancreatic cancer. It is unlikely that immunological mechanisms are involved in this response. These inhibitory effects on tumor growth could be mediated by creating a state of sex hormone deprivation of D-Trp-6-LH-RH and by inhibition of the release and/or action of gastrointestinal hormones and growth factors by the somatostatin analog RC-160.

Effect of long-acting LHRH analog (Zoladex) on prostate cancer: evaluated by transrectal ultrasonography

Transrectal ultrasonography has proved valuable in assessing the effect of primary treatment modalities for prostate carcinoma. This study shows patients who had a significant reduction in primary tumor volume had a significantly better prognosis and had less local symptoms than did the group of patients that did not have a significant reduction (less than 50%) in primary volume secondary to therapy. Patients were treated with either castration or Zoladex and all had Stage D2 cancer of the prostate.

Short-term utilization of a gonadotropin-releasing hormone agonist (buserelin) for induction of ovulation in an in vitro fertilization program

Benefits of the short-term utilization of a gonadotropin-releasing hormone (GnRH) agonist (Buserelin, Hoechst, AG, Frankfurt am Mein, FRG) for induction of ovulation in an in vitro fertilization program (IVF) program were assessed. Eighteen patients underwent consecutively an induction of ovulation by clomiphene citrate (CC) and human menopausal gonadotropin (hMG), then by hMG alone, and finally by Buserelin and hMG. The switchover from CC and hMG to hMG alone significantly increased the number of aspirated follicles and the oocyte recovery rate. The addition of Buserelin prevented the outcome of spontaneous luteinizing hormone (LH) surges. It reduced the preovulatory luteinization and increased the number of recovered oocytes as well as the number of embryos available for transfer. A 33% clinical pregnancy rate per ovum pick-up was achieved with the Buserelin-hMG treatment.

LHRH analogues in the management of uterine fibroids, premenstrual syndrome and breast malignancies

Agonist analogues of LHRH are of potential value in the management of oestrogen-dependent conditions in women. However, their clinical effectiveness is a direct consequence of ovarian suppression which is in itself associated with adverse effects, in particular loss of bone mass. They are thus unsuitable for long-term use in premenopausal women with benign conditions but in future may have a wider role in combination with other agents. In women with uterine fibroids, therapy leads to reduction of uterine volume and alleviation of symptoms although the benefit is rapidly reversed when therapy ceases. Although there is a theoretical potential for combined therapy, successful combinations have yet to be identified. Thus, at the present time, agonists of LHRH do not offer a true alternative to surgery for the majority of women. They will be of value where there is a contra-indication to surgery and for women approaching the age of the natural menopause. They may also be of use prior to surgery, both in controlling symptoms and in reducing surgical morbidity and blood loss. LHRH agonists appear to be beneficial in the management of some women with severe premenstrual tension but intensify symptoms in others. Particular care is required in selection of women for such therapy because of the uncertain nature of the condition and its high rate of response to placebo therapy. Response is dependent on the degree of ovarian suppression and long-term use of LHRH agonists alone is clearly undesirable. However LHRH agonists alone or in combination with ovarian steroids are of potential value as a research tool. In premenopausal women with advanced breast cancer, concerns about the long-term effects of therapy with LHRH agonists are less important and these drugs offer a medical alternative to oophorectomy as first-line treatment in women with oestrogen receptor-positive tumours. Future developments are likely to include evaluation of combined therapy and comparative studies in women with early disease. As such studies involve long-term treatment, they will generate very useful information about the effects of therapy. This will be of great value to clinicians evaluating the role of LHRH agonists in the management of benign conditions.

Dermatopharmacology: drugs around the corner

This article describes impending advances in drug treatment of skin diseases. We have included the following categories: (1) interesting new drugs for which there are reasonable prospects of eventual licensing for skin indications, (2) important novel compounds whose progress through licensing procedures, although incomplete at the time of writing, is advanced, and (3) new indications or improved regimens that have recently emerged for established drugs.