Combined nestorone-testosterone gel suppresses serum gonadotropins to concentrations associated with effective hormonal contraception in men

BACKGROUND

Novel male-based contraceptives are needed to broaden family planning choices. A progestin, Nestorone^® (Nes) gel, plus a testosterone (T) gel suppresses sperm concentrations to levels associated with effective contraception in normal men. However, administration of two gels on different parts of the body daily is impractical.

OBJECTIVE

Compare the effectiveness of daily application of a single, combined 8.3 mg Nes-62.5 mg T gel (Nes-T) vs. 62.7 mg T gel to suppress serum FSH and LH concentrations to ≤1.0 IU/L (a threshold associated with suppression of sperm concentrations to ≤1 million and effective contraception) and to compare the pharmacokinetics of serum Nes and T concentrations between the gel groups.

DESIGN

We conducted a 28-day, double-blind, controlled trial of 44 healthy men randomized to daily Nes-T or T gel with measurement of hormones at baseline, treatment, and recovery and during 24-h pharmacokinetic studies on days 1 and 28 of treatment.

RESULTS

Of the subjects who met pre-defined inclusion criteria, 84% of the Nes-T group suppressed serum gonadotropin concentrations to ≤1.0 IU/L at days 21-28 vs. 16.7% in the T group (p < 0.001). On day 1, Nes concentrations rose significantly above baseline by 2 h and continued to rise up to 24 h after Nes-T gel application. Nes concentrations were not detectable in the T group. Serum total T concentrations rose and were significantly higher in the T gel group compared to the Nes-T group at 24 h on day 1 and days 11, 14, and 21 (p < 0.01). There were no serious adverse events in either group. About 80% of the subjects reported satisfaction with both gels.

CONCLUSION

Daily Nes-T gel effectively and safely suppresses serum gonadotropins and is acceptable to most men. It should be studied further in efficacy trials of hormonal male contraception.

Preventing secondary exposure to women from men applying a novel nestorone/testosterone contraceptive gel

BACKGROUND

Testosterone (T)/Nestorone (NES) combination gel is a potential transdermal male contraceptive that suppresses gonadotropins and spermatogenesis. Transfer of transdermal T from men to women can be prevented by washing or covering application sites with clothing.

OBJECTIVES

We hypothesized that showering or wearing a shirt over gel application sites would prevent secondary exposure of T and NES to a woman after close skin contact.

MATERIALS AND METHODS

Twelve healthy male and 12 healthy female participants were recruited. Men applied T/NES 62 mg/8 mg gel to their shoulders and upper arms. Two hours after application, female partners rubbed the application site for 15 min. Exposure in the female partner was assessed under three conditions: a shirt covered the application site; the man showered prior to skin contact; or without intervention to reduce transfer. Serum T and NES concentrations were measured by LC-MS/MS in serial blood samples for 24 h after gel exposure.

MAIN OUTCOMES

Change in female serum T and NES levels as measured by average concentration over 24 h (C_avg ).

RESULTS

Median female serum T C_avg was 23.9 ng/dL (interquartile range, 19.3, 33.9) with the shirt barrier and 26.7 ng/dL (20.7, 33.9) after showering, which was higher than baseline 20.9 ng/dL (16.7, 25.0), both p < 0.03) but lower than without intervention (58.2 ng/dL [30.9, 89.1], both p < 0.01). Female serum NES C_avg and maximum concentration were below the lower limit of quantification with the shirt barrier and after showering, but increased without intervention in six of 12 women (maximum concentration <60 pg/mL). Men had lower average serum NES levels after showering (47 pg/ml [20, 94] compared to no intervention (153.3 pg/mL [51, 241], p < 0.02).

CONCLUSION

Secondary transfer of T and NES occurs after intensive skin contact with the gel application site. Secondary transfer is decreased by a shirt barrier or showering before contact.

Non-clinical studies of progesterone

Progesterone is a steroid hormone that is essential for the regulation of reproductive function. Progesterone has been approved for several indications including the treatment of anovulatory menstrual cycles, assisted reproductive technology, contraception during lactation and, when combined with estrogen, for the prevention of endometrial hyperplasia in postmenopausal hormonal therapy. In addition to its role in reproduction, progesterone regulates a number of biologically distinct processes in other tissues, particularly in the nervous system. This physiological hormone is poorly absorbed when administered in a crystalline form and is not active when given orally, unless in micronized form, or from different non-oral delivery systems that allow a more constant delivery rate. A limited number of preclinical studies have been conducted to document the toxicity, carcinogenicity and overall animal safety of progesterone delivered from different formulations, and these rather old studies showed no safety concern. More recently, it has been shown in animal experiments that progesterone, its metabolite allopregnanolone and structurally related progestins have positive effects on neuroregeneration and repair of brain damage, as well as myelin repair. These recent preclinical findings have the potential to accelerate therapeutic translation for multiple unmet neurological needs.

Neuraxial analgesia is not associated with an increased risk of post-partum relapses in MS

Background:

Obstetrical analgesia remains a matter of controversy because of the fear of neurotoxicity of local anesthetics on demyelinated fibers or their potential relationship with subsequent relapses.

Objective:

To assess the impact of neuraxial analgesia on the risk of relapse during the first 3 months post-partum, with a focus on women who experienced relapses during pregnancy.

Methods:

We analyzed data of women followed-up prospectively during their pregnancies and at least 3 months post-partum, collected in the Pregnancy in Multiple Sclerosis (PRIMS) and Prevention of Post-Partum Relapses with Progestin and Estradiol in Multiple Sclerosis (POPARTMUS) studies between 1992–1995 and 2005–2012, respectively. The association of neuraxial analgesia with the occurrence of a post-partum relapse was estimated by logistic regression analysis.

Results:

A total of 389 women were included, 215 from PRIMS and 174 from POPARTMUS. In total, 156 women (40%) had neuraxial analgesia. Overall, 24% experienced a relapse during pregnancy and 25% in the 3 months post-partum. Women with a pregnancy relapse were more likely to have a post-partum relapse (odds ratio (OR) = 1.83, p = 0.02), independently of the use of neuraxial analgesia. There was no association between neuraxial analgesia and post-partum relapse (OR = 1.08, p = 0.78).

Conclusion:

Neuraxial analgesia was not associated with an increased risk of post-partum relapses, whatever multiple sclerosis (MS) activity during pregnancy.

Continuous dosing of a novel contraceptive vaginal ring releasing Nestorone® and estradiol: pharmacokinetics from a dose-finding study

BACKGROUND

As part of a program to develop a novel estradiol-releasing contraceptive vaginal ring (CVR), we evaluated the pharmacokinetic (PK) profile of CVRs releasing segesterone acetate (Nestorone® (NES)) combined with one of three different estradiol (E₂) doses.

STUDY DESIGN

A prospective, double-blind, randomized, multi-centered study to evaluate a 90-day CVR releasing NES [200mcg/day] plus E₂, either 10mcg/day, 20mcg/day, or 40mcg/day in healthy reproductive-age women with regular cycles. Participants provided blood samples twice weekly for NES and E₂ levels during the first 60 days (ring 1) and the last 30 days (ring 2) of use. A subset underwent formal PK assessments at ring initiation, ring exchange (limited PK), and study completion.

RESULTS

The main study enrolled 197 women; 22 participated in the PK substudy. Baseline characteristics between the main and PK participants were comparable, with an average BMI of 25.8 kg/m² (SD 4.3). In the PK substudy, all three rings showed similar NES PK: mean area under the curve (AUC_(0-72)) 34,181 pg*day/mL; concentration maximum (C_max) 918 pg/mL; time to maximum concentration (T_max) 3.5 h. For E_2, the C_max occurred at 2 h, and was significantly higher with the 20 mcg/day ring (mean 390 pg/mL); 10 mcg/day, 189 pg/mL, p=.003; 40 mcg/day, 189 pg/mL, p<.001), and declined rapidly to≤50 pg/mL for all doses by 24 h. For all subjects, the median E₂ levels remained under 35 pg/mL during treatment.

CONCLUSION

PK parameters of NES were not affected when paired with different doses of E₂, but E₂ levels from all three doses were lower than anticipated and no dose response was observed.

IMPLICATIONS

While these novel estradiol-releasing combination contraceptive vaginal rings provided sustained release of contraceptive levels of Nestorone over 90 days, the E₂ levels achieved were not consistent with bone protection, and a dose-response was not observed.

Neurosteroidogenesis and progesterone anti-inflammatory/neuroprotective effects

Progesterone shows anti-inflammatory and promyelinating effects in mice with experimental autoimmune encephalomyelitis (EAE), a commonly used model for multiple sclerosis (MS). Because neurosteroids have been implicated as protective factors for MS and EAE, we analysed the expression of neurosteroidogenic enzymes in the compromised spinal cord of EAE mice. EAE was induced in female C57Bl6 mice, which were then killed on day 16 after induction. Progesterone was given by pellet implantation 1 week before EAE induction. Untreated EAE mice showed decreased mRNAs for the steroidogenic acute regulatory protein (Star), voltage-dependent anion channel (VDAC), cholesterol side-chain cleavage (P450scc), 5α-reductase, 3α-hydroxysteroid dehydrogenase (3α-HSOR) and aromatase, whereas changes of 3β-hydroxysteroid dehydrogenase (3β-HSD) were not significant. mRNA translocator protein (18 kDa) (TSPO) was elevated, concomitantly with a reactive microgliosis. EAE mice also showed abnormal mitochondrial ultrastructure in axons and neuronal bodies, as well as reduced expression of fission and fusion protein mRNAs. Progesterone pretreatment before EAE induction increased Star, VDAC, P450scc, 5α-reductase type I, 3α-HSOR and aromatase mRNAs and did not modify 3β-HSD. TSPO mRNA was decreased, possibly as a result of reversal of microgliosis. Progesterone pretreatment also improved mitochondrial ultrastructure and increased fission/fusion protein mRNAs. These mitochondrial effects may be part of the progesterone recovery of neurosteroidogenesis. The enzymes 3β-HSD, 3α-HSOR and 5α-reductase are also responsible for the formation of androgens. Because MS patients and EAE rodents show changes of central androgen levels, it is likely that, together with progestins and oestrogens, neuroandrogens afford neuroprotection for EAE and MS. The data reviewed suggest that enhanced synthesis of neurosteroids contributes in an auto/paracrine manner to reinforce the neuroprotective and anti-inflammatory effects of exogenous progesterone given to EAE mice.

Revisiting the roles of progesterone and allopregnanolone in the nervous system: resurgence of the progesterone receptors

Progesterone is commonly considered as a female reproductive hormone and is well-known for its role in pregnancy. It is less well appreciated that progesterone and its metabolite allopregnanolone are also male hormones, as they are produced in both sexes by the adrenal glands. In addition, they are synthesized within the nervous system. Progesterone and allopregnanolone are associated with adaptation to stress, and increased production of progesterone within the brain may be part of the response of neural cells to injury. Progesterone receptors (PR) are widely distributed throughout the brain, but their study has been mainly limited to the hypothalamus and reproductive functions, and the extra-hypothalamic receptors have been neglected. This lack of information about brain functions of PR is unexpected, as the protective and trophic effects of progesterone are much investigated, and as the therapeutic potential of progesterone as a neuroprotective and promyelinating agent is currently being assessed in clinical trials. The little attention devoted to the brain functions of PR may relate to the widely accepted assumption that non-reproductive actions of progesterone may be mainly mediated by allopregnanolone, which does not bind to PR, but acts as a potent positive modulator of γ-aminobutyric acid type A (GABA(A) receptors. The aim of this review is to critically discuss effects of progesterone on the nervous system via PR, and of allopregnanolone via its modulation of GABA(A) receptors, with main focus on the brain.

Characteristics associated with suppression of spermatogenesis in a male hormonal contraceptive trial using testosterone and Nestorone(®) gels

Development of a male hormonal contraceptive has been challenging ascribable to the failure to adequately suppress spermatogenesis in 5-10% of men. Methods to identify incomplete suppressors early in treatment might identify men most responsive to male hormonal contraceptives. We hypothesized that serum hormone and gonadotropin concentrations after 4 weeks of transdermal treatment with testosterone and Nestorone in a contraceptive trial would be associated with suppression of sperm concentrations to <1 million/mL after 24 weeks. Indeed, luteinizing hormone or follicle-stimulating hormone concentrations greater than 1 IU/L after 4 weeks of transdermal testosterone/nestorone treatment were 97% sensitive for predicting failure to suppress spermatogenesis after 24 weeks of treatment. Serum nestorone concentrations were significantly associated with suppression, but serum testosterone concentrations were not. Early suppression of gonadotropins is associated with, but does not ensure, adequate suppression of spermatogenesis. This information may allow for rapid identification of non-responders in male hormonal contraceptive trials.

7α-methyl-19-nortestosterone vs. testosterone implants for hypogonadal osteoporosis: a preclinical study in the aged male orchidectomized rat model

Overt male hypogonadism induces not only osteoporosis but also unfavourable changes in body composition, which can be prevented by testosterone (T) replacement. In this preclinical study, the potential of synthetic androgen 7α-methyl-19-nortestosterone (MENT) as alternative treatment for male hypogonadism was evaluated in comparison with T. Eleven-month-old male rats were orchidectomized (orch) and left untreated for 2-months. Subsequently, the effects of 4-month MENT (12 μg/day) and T (72 μg/day) treatment on bone, muscle and fat were analysed using microcomputed tomography, dual-energy X-ray absorptiometry, dynamic bone histomorphometry and muscle fibre typing. At the onset of treatment, orch rats were clearly hypogonadal. This was evidenced by significant reductions of androgen-sensitive organ weight, lean mass, cortical thickness and trabecular bone volume compared with sham-operated aged-matched controls (sham). MENT and T restored weight of androgen-sensitive organs to a similar extent, with a superior anabolic action of MENT on levator ani muscle. Both androgens not only fully rescued hypogonadal loss of lean mass but also restored muscle fibre type composition and trabecular bone volume. Cortical bone loss was similarly prevented by MENT and T, but without full recovery to sham. Both androgens stimulated periosteal bone formation, but with a stronger effect of T. By contrast, MENT more strongly suppressed endocortical bone formation and bone turnover rate and reduced fat mass and serum leptin to a greater extent than T. MENT and T are both effective replacement therapies to stimulate bone and muscle in hypogonadal rats, with stronger lipolytic action of MENT.

Pharmacology and clinical applications of selective estrogen receptor modulators

Compounds that can be described as selective estrogen receptor modulators (SERMs) have expanded dramatically over the past two decades. The ability of SERMs to act as estrogens in certain tissues while remaining inert or acting as an anti-estrogen in other tissues has opened up opportunities for treating specific estrogen-modulated diseases without accepting the risk of systemic estrogen activity. SERM development has resulted in significant therapeutic advances for breast cancer, osteoporosis and potentially other diseases associated with the menopause. After the publication of the Women's Health Initiative, interest in compound selectivity that reduces menopausal symptoms while protecting bone, breast, uterus and the heart has increased. Future SERMs may also have a therapeutic profile that can be tailored to specific patient populations, including men. This review paper summarizes the characteristics of different SERMs from various pharmacological categories and the feasibility and scope of their use for a large range of disease/health conditions.

Central modifications of allopregnanolone and beta-endorphin following subcutaneous administration of Nestorone

The aim of the present study was to evaluate the potential action of Nestorone (alone or in combination with estradiol valerate) on the level of allopregnanolone and of the opioid beta-endorphin in selected brain areas. Wistar ovariectomized rats were given 0.05 mg/(kg day) of estradiol valerate (E2V) or subcutaneous Nestorone at three dose levels: low dose (10 microg/(kg day)), antiovulatory dose (50 micro/(kg day)) and high dose (250 microg/(kg day)) with and without E2V. E2V therapy reversed the reduction of allopregnanolone and beta-endorphin induced by ovariectomy anywhere was analyzed except for the adrenal gland. Nestorone showed no effect on allopregnanolone concentration in serum or any part of the brain tissue when given alone while it had a synergistic increasing effect in allopregnanolone concentration in some parts of the brain (hippocampus, hypothalamus, anterior pituitary and serum) when given at high dose of 250 microg/(kg day) in combination with E2V. At lower doses it possesses a synergistic effect with E2V only in the hippocampus (at 50 microg/(kg day)) and in the anterior pituitary (at 10 and 50 microg/(kg day)). Nestorone administered alone at any dose led to significant increase in beta-endorphin levels in the hippocampus only while, in the high dose group, there was a significant increase in endorphin levels in anterior pituitary and hypothalamus in addition to hippocampus as compared to ovariectomized control rats. In addition, only the highest dose of Nestorone added to estrogen increased beta-endorphin levels of hippocampus and plasma. Thus the lower doses of Nestorone alone or in combination with estrogen do not seem to exert any great effect on both allopregnanolone and beta-endorphin. It is only the highest dose of Nestorone that increases allopregnanolone and beta-endorphin levels in selected brain areas, which are the hippocampus, the hypothalamus, the anterior pituitary and serum/plasma. This suggests that Nestorone at the antiovulatory dose levels may not alter the positive effects of estrogen treatment on mood and behaviour.

Pharmacology of different progestogens: the special case of drospirenone

The pharmacological properties of progestins used in contraception and hormone replacement therapy (HRT) vary, depending upon the molecules from which they are derived. Very small structural changes may induce considerable differences in effects. It is unclear if the currently available progestins are able to bind specifically to the progesterone receptors, PR-A or PR-B. The clinical relevance of more specific binding to one or the other isoforms of the progesterone receptor is still unknown. The development of new generations of progestins, with improved receptor-selectivity profiles, has been a great challenge. Steroidal and non-steroidal progesterone agonists have also been synthesized, although these molecules are at a very early stage of development. Several new progestins have been synthesized in the past decade, including dienogest, drospirenone, Nestorone, nomegestrol acetate and trimegestone. Drospirenone differs from the classic progestins in its derivation from spirolactone. The major effect of drospirenone is antimineralocorticoid activity. By that property, drospirenone causes decreased salt and water retention, and thus lowering of blood pressure. The affinity of drospirenone for the mineralocorticoid receptor is about five times that of aldosterone, the naturally occurring mineralocorticoid. In addition, drospirenone has no androgenic effect, but does exhibit partial antiandrogenic activity; its antiandrogenic potency is about 30% of that of cyproterone acetate, the progestin with the most potent antiandrogenic activity. This property, shared by several new progestins, may counteract the negative effect of androgens on hair growth, lipid changes, insulin and, possibly, body composition in postmenopausal women. Drospirenone has a long terminal half-life (about 32 hours), and its bioavailability is about 76%. Drospirenone, which has pharmacodynamic properties very similar to those of progesterone, has been developed as a combined oral contraceptive (30 microg ethinylestradiol/3 mg drospirenone; Yasmin, Schering AG, Berlin, Germany). Drospirenone is also available in combination with estradiol as an HRT preparation (1 mg 17beta-estradiol/2 mg drospirenone; Angeliq, Schering AG).

New hormonal therapies and regimens in the postmenopause: routes of administration and timing of initiation

Since the publication of the Women's Health Initiative (WHI) study followed by the results of the Million Women Study (MWS), the role of hormonal therapy in postmenopausal women has been further challenged. The risks attributed to hormone therapy have been overestimated and the data has been wrongly extrapolated to the whole class of therapies. The trends in postmenopausal hormonal therapy seem now to favor the non-oral delivery routes for both the estrogen and the progestin for women with an intact uterus, based on the assumption that a lesser stimulation of the liver proteins and a neutral metabolic profile would be more favorable in terms of cardiovascular and venous risk. The combination of non-oral administration of estradiol and local delivery of progesterone or a progestin such as levonorgestrel by means of gels, sprays, vaginal rings or intrauterine systems would represent new methods of replacement therapy for the menopausal woman, improving compliance and minimizing the risks of hormone replacement. Several of these systems are either available or in development. Long-term studies on the risk/benefit of various non-oral formulations are certainly warranted.

Role of progestins with partial antiandrogenic effects

An experts' meeting on the 'Role of progestins with partial antiandrogenic effects' was held in Berlin from January 19 to 22, 2001. The meeting was chaired by Dr R. Sitruk-Ware (New York, USA) and participants included Ms F. Fruzzetti (Pisa, Italy), J. Hanker (Trier, Germany), J. Huber (Vienna, Austria), F. Husmann (Bad Sassendorf, Germany), S. O. Skouby (Copenhagen, Denmark), J. H. H. Thijssen (Utrecht, The Netherlands), and R. Druckmann (Nice, France). The present paper reports the conclusions of the meeting. However, the publication of the Women's Health Initiative study, which appeared after the meeting, led to additional comments and revisions.

Alternatives for optimal hormone replacement therapy

To satisfy the needs of women with a wide variety of different medical histories and preferences, a wide choice of various forms of hormone replacement therapy (HRT) is desirable. The potential long-term benefits of HRT, in terms of osteoporosis, cardiovascular disease and dementia, require good compliance, which in turn requires an HRT formulation that is highly acceptable. An absence of weight gain and lack of androgenic effects are of great importance, as are predictable bleeding and positive effects on postmenopausal symptoms and quality of life. HRT should be tailored to each woman's needs by the choice of appropriate estrogens and particularly a progestogen with a suitable pharmacological profile. An ideal progestogen should be targeted at preventing endometrial hyperplasia without opposing the effects of estrogen on the vessels. Several new progestogens have been synthesized in recent years. Dienogest, the progestogenic component of a new hormone replacement therapy with estradiol valerate, has many desirable features, including antiandrogenic properties; in this respect, it is unique amongst progestogens derived from testosterone. Tailored HRT should treat symptoms, minimize risk factors, meet personal preferences and lifestyle needs, and not be contraindicated for concomitant diseases. During the next decade, optimal HRT must match a number of trends, including an aging population, and is likely to be influenced by the outcome of major trials such as the Women's Health Initiative trial whose negative results will impact the prescriptions, the advent of new compounds--particularly the selective estrogen receptor modulators and progestogen receptor modulators--and the introduction of new methods of delivery, including vaginal rings and medicated intrauterine systems.

Progestins and cardiovascular risk markers

Several risks are attributed to progestins as a class-effect; however, the progestins used in hormone replacement therapy (HRT) have varying pharmacologic properties and do not induce the same side effects. Natural progesterone (P) and some of its derivatives, such as the 19-norprogesterones, do not exert any androgenic effect and, hence, have no negative effect on the lipids. On the other hand, the 19-nortestosterone derivatives and even some 17-hydroxyprogesterones have a partial androgenic effect, which may explain some of the negative effects observed on surrogate markers of cardiovascular risk. The relevance of the lipid changes induced by sex steroids has been questioned, and studies in the female cynomolgous monkey have not shown a direct relationship to atherosclerosis. Results suggest that estrogens (E) have antiatherogenic effects and that P does not reverse the beneficial effect of estradiol. Also, sex hormones modulate the vasomotor response of the main arteries. E preserves the normal endothelium-mediated dilation of coronary arteries, and P does not reverse this potential cardioprotective mechanism. In the same animal model, the addition of cyclic or continuous medroxyprogesterone acetate (MPA) to E inhibited vasodilatation by 50%, while nomegestrol acetate did not diminish the E-induced vasodilatation. Not all progestins act similarly on vasomotion or affect cardiovascular risk factors in the same way. Progestins, such as MPA or norethisterone acetate (NETA), exert a partial detrimental effect on the beneficial actions of estrogens with regard to lipid changes, atheroma development, or vasomotion. In contrast, progesterone itself does not have this inhibitory effect on lipid changes and vascular reactivity in animal models or on exercise-induced myocardial ischemia in humans. Nonandrogenic molecules of P itself and of derivatives, such as 19-norprogesterones, would appear neutral on the vessels. Several ongoing randomized controlled trials of HRT are focusing on primary or secondary prevention of coronary heart disease. Unfortunately, most of these large trials have selected the same HRT regimen for their study design. Further studies with other treatment regimens are thus needed and should consider the various steroids used in different countries.

Approval of mifepristone (RU 486) in Europe

The discovery of mifepristone (ex-RU486) was the achievement of a large research programme on steroidal compounds with antihormone properties conducted at Roussel Uclaf in partnership with the INSERM unit of Pr. E. E. Baulieu. Mifepristone exhibited a strong affinity to the progesterone and the glucocorticoid receptors. Consequently, it exerted competitive antagonism to these hormones both in in vitro and animal experiments. The identification of the antiprogesterone activity led to propose mifepristone use for the termination of early human pregnancy. Mifepristone at the dose of 600 mg initially used alone, was then used with a subsequent low dose of prostaglandins that led to a success rate of 95% as a medical method for early termination of pregnancy. In parallel, other indications were extended to the cervical dilatation prior to surgical termination of pregnancy in the first trimester, in the therapeutic termination of pregnancy for medical reasons beyond the first trimester, and for labour induction in case of fetal death in utero. The efficacy and safety of that treatment have been confirmed on the basis of more than 10 years of use with close adherence to the approved recommendations. Besides the political and philosophical hurdles that delayed clinical research with this molecule, other potential indications either in gynecological or cancer areas should be further developed.

[Anti-progesterones]

THERAPEUTIC APPLICATIONS

Antiprogestins are a promising class of therapeutic agents in the field of reproductive health. Mifepristone (exRU486) remains the leading compound of this class and is the only one presently used in clinical practice. Beyond the main action of antiprogestins on human pregnancy, these compounds may prove useful in the treatment of uterine leiomyomas and endometriosis, and for contraception. IN CANCEROLOGY: Rare tumors such as meningiomas or leiomyoarcomas expressing progesterone receptors may be successfully treated with these antihormones. MAIN INDICATIONS: The main characteristics of the different antiprogestins discovered so far are addressed and the key results from the large clinical studies conducted with mifepristone are described here for indications where the product is approved for clinical use: medical termination of pregnancy during the first trimester, cervical dilatation prior to surgical termination of pregnancy, preparation for prostaglandin action in the therapeutic termination of pregnancy beyond the first trimester, labor induction in case of foetal death in utero.

Percutaneous progesterone use and risk of breast cancer: results from a French cohort study of premenopausal women with benign breast disease

Percutaneous progesterone topically applied on the breast has been proposed and widely used in the relief of mastalgia and benign breast disease by numerous gynecologists and general practitioners. However, its chronic use has never been evaluated in relation to breast cancer risk. The association between percutaneous progesterone use and the risk of breast cancer was evaluated in a cohort study of 1150 premenopausal French women with benign breast disease diagnosed in two breast clinics between 1976 and 1979. The follow-up accumulated 12,462 person-years. Percutaneous progesterone had been prescribed to 58% of the women. There was no association between breast cancer risk and the use of percutaneous progesterone (RR = 0.8; 95% confidence interval 0.4-1.6). Although the combined treatment of oral progestogens with percutaneous progesterone significantly decreased the risk of breast cancer (RR = 0.5; 95% confidence interval 0.2-0.9) as compared with nonusers, there was no significant difference in the risk of breast cancer in percutaneous progesterone users versus nonusers among oral progestogen users. Taken together, these results suggest at least an absence of deleterious effects caused by percutaneous progesterone use in women with benign breast disease.

Progestins and cancer

The role of progestins in breast tissue is less well defined than in the endometrium. Although in vitro studies have shown that progestins induce a similar decrease in both estrogen and progesterone receptors and an increase in 17beta-estradiol dehydrogenase in the breast as in the endometrium, epidemiologic studies have suggested that progestins prevent endometrial cancer, but do not reverse the estrogen-related increase in breast cancer risk in long-term hormone-replacement therapy (HRT). Other studies have also suggested a protective effect for progestins on breast tissue. The dual effect of progesterone and progestins on the cell cycle has been demonstrated, suggesting that according to the duration of administration, the same steroid can induce cells to enter the multiplication phase or to enter a resting state. Progestins exert different effects according to the steroid from which they are derived, e.g. pregnanes derived from progesterone, estranes or gonanes derived from testosterone. Some estrane derivatives are able to stimulate breast cell multiplication in vitro through an estrogen receptor-mediated pathway. Most pregnanes do not exert such an effect. Also, some pregnane derivatives stimulate apoptosis, leading to cell death. However, it is well established that high doses of progestins have been successfully used in the treatment of advanced breast cancer as second-line endocrine therapy. Finally, striking differences have been observed in progestin use in Europe and in the USA. In France, where the rate of progestin use per head is higher than in the USA, the rate of breast cancer has not increased as sharply as observed in North America. Although cancer genesis is multifactorial, it may be concluded that progestins do protect endometrial tissue against the proliferative action of estrogen and if they do not protect breast tissue, at least they do not stimulate its proliferation. Also, they are useful agents as a second-line therapy for breast cancer, when used at high doses.

Progestins in the menopause

While the benefits of progestin use in hormone replacement therapy (HRT) are well recognised as far as endometrial protection is concerned, their risks and drawbacks have generated controversial articles. The data related to the progestin effect on breast tissue has been interpreted differently from country to country. However it has been admitted that, according to the type of progestin used, the dose and duration of its application, a predominant antiproliferative effect is observed in the human breast cells. As far as breast cancer risk is concerned, most epidemiological studies do not suggest any difference between the estrogens given alone or combined to progestins in HRT. When the cardiovascular risk factors are considered, some molecules with a higher androgenic potency than others, attenuate the beneficial effects of estrogens on the lipid profile and the vasomotion as well. On the other hand, other progestins devoid of androgenic properties do not exert these deleterious effects. The epidemiological data does not suggest any negative effect of the progestins administered together with estrogens on cardiovascular morbidity or mortality. However, recent results suggest that in women with established coronary heart disease (CHD), HRT may not protect against further heart attacks, when the progestin selected possesses androgenic properties. Complying with the classic contra indications of HRT and selecting molecules devoid of estrogenic, androgenic, or glucocorticoid effect should allow a larger use of the progestins without any major drawback.

Progestins and breast cancer

In the last years there has been an extraordinary development in the synthesis of new progestins. These compounds are classified, in agreement with their structure, in various groups which include progesterone, retroprogesterones, 17alpha-hydroxyprogesterones, 19-norprogesterones, 17alpha-hydroxyprogesterone derivatives, androstane and estrane derivatives. The action of progestins is a function of many factors: its structure, affinity to the progesterone receptor or to other steroid receptors, the target tissue considered, the biological response, the experimental conditions, dose, and metabolic transformation. The information on the action of progestins in breast cancer patients is very limited. Positive response with the progestins: medroxyprogesterone acetate and megestrol acetate was obtained in post-menopausal patients with advanced breast cancer. However, extensive information on the effect of progestins was obtained in in vitro studies using hormone-dependent and hormone-independent human mammary cancer cell lines. It was demonstrated that in the hormone-dependent breast cancer cells, various progestins (nomegestrol acetate, tibolone, medrogestone, promegestone) are potent sulfatase inhibitory agents. The progestins can also involve the inhibition of mRNA of this enzyme. In another series of studies it was also demonstrated that various progestins are very active in inhibiting the 17beta-hydroxysteroid dehydrogenase for the conversion of estrone to estradiol. More recently it was observed that the progestins promegestone or medrogestone stimulate the sulfotransferase for the formation of estrogen sulfates. Consequently, the blockage in the formation of estradiol via sulfatase, or the stimulatory effect on sulfotransferase activity, by progestins can open interesting and new possibilities in clinical applications in breast cancer.

[Topical hormonal treatment and urogenital atrophy]

Hypoestrogenemia-derived urogenital symptoms after menopause manifest after some years of hormonal deficit and appear commonly in elderly, untreated women. In the urogenital tract low postmenopausal estrogen levels lead to vaginal irritation and dryness and to dyspareunia, often accompanied by other symptoms like uriesthesis, incontinence or recurrent infections. Every systemic estrogen treatment is accepted as efficient for the correction of urogenital symptoms, often even at doses lower than those necessary for the correction of vasomotor symptoms. Diverse local treatments have been proposed: estriol, promestriene and low-dose estrone or estradiol. Promestriene applied locally stimulates differentiation and maturation of vaginal mucosa and compensates local hypoestrogenic effects without marked hormonal effects outside the vagina. Vaginal application of estrone, on the other hand, has rather been proposed for systemic hormone substitution and elevated levels of estrone and estradiol observed in the plasma render this method in-appropriate in cases where strictly local effects are desired. Recently, very low doses of estradiol in a range of 7.5 micrograms/day have been proposed for the treatment of urogenital atrophy by means of a prolonged release regimen. Among the described preparations, those with strictly local (devoid of systemic) effects should be restricted to patients with contraindications for systemic substitution therapy. Local estrogen therapies are recommended for the treatment of complaints due to vulvar and vaginal atrophy. They have also been proposed by certain authors for the acceleration of the cervico-vaginal and vulvar cicatrisation after surgical interventions or postpartum. The presence of miction disorders in elderly postmenopausal women is also a point in favour of local treatment.

[Pharmacology of oral contraceptives]

Oral contraceptives include two types of steroids; ethinyl-estradiol as the main estrogenic component which dose vary from 20 to 50 micrograms per tablet (mostly 30 to 35 micrograms) and progestins essentially derivatives of 19 nortestosterone. Derivatives of 19 norprogesterone such as nomegestrol acetate or ST 1435 are not used as oral contraceptives but are being evaluated through parenteral administration, e.g. implants or transdermal systems. The assessment of the pharmacological properties of these progestins indicate a high antigonadotropic and a high antiestrogenic properties for levonorgestrel and for the newer gestagens as well. Therefore very low doses are being used in the current oral contraceptives. However, there is a lower margin of security with the low dose contraceptives than with previous standard combinations and especially when concomitant medications are ingested such as enzyme-inducing agents. Selection of contraceptive methods should be discussed when specific co-medications are necessary.

Transdermal application of steroid hormones for contraception

The concept of transdermal delivery (TD) for steroid application has nowadays been largely accepted for hormone replacement therapy in the menopause. It is only recently that the same concept has been envisaged for contraception. The skin can be penetrated by both estrogens and progestins, provided they are delivered in an appropriate solvent. About 10% of the total dose applied topically is actually absorbed. The transdermal delivery systems (TDS) presently available are either of the reservoir type (membrane-moderated system) or of the matrix dispersion type where the drug is dispersed into a polymer matrix. Estradiol (E2) is the most appropriate steroid for TD and can be combined with progestins to ensure a contraceptive effect. Only potent progestins should be used to achieve effective plasma levels with low doses in order to maintain an acceptable small surface of TDS. TDS changed weekly and delivering both E2 and levonorgestrel (L-NG) at daily dosages of 38.4 (+/- 7.5) and 28.8 (+/- 7.2) micrograms/10 cm2 per day respectively, showed ovulation suppression. Another progestin derived from norprogesterone (ST 1435) has been shown to penetrate the skin when suspended in acetylated lanolin or dissolved in a hydroalcoholic gel and to ensure ovulation suppression at a dose of 2 mg per day in a small number of cycles. These preliminary data demonstrate the feasibility of suppressing ovulation in women by transdermal absorption of steroids. Using TDS for contraception implies that such systems should be perfectly adhesive, well tolerated locally and achieve nearly 100% efficacy. These targets are very challenging, however, the potential advantages are so high that the concept deserves further development.

Cardiovascular risk at the menopause--role of sexual steroids

From epidemiological and experimental evidence it has been concluded that ovarian steroids have a large variety of cardiovascular effects. Among these are a direct action on the vascular wall, alterations in hemodynamics, modification of protein metabolism involved in the arteriosclerosis process, and alterations in the risk of cardiovascular morbidity and mortality. Some of the earlier epidemiological studies indicated an increased risk of cardiovascular disease (CVD) in estrogen users, but later on the majority of the published studies reported consistently a striking decrease in CVD by about 50%. The consistency in the positive results observed in successive epidemiological reports from various countries strongly suggest a protective effect of hormone replacement therapy on CVD morbidity. However, the direct demonstration of a protective effect of estrogens on CVD morbidity and mortality can only be made by long-term prospective controlled studies.

Progestogen use and decreased risk of breast cancer in a cohort study of premenopausal women with benign breast disease

A cohort study of 1,150 premenopausal French women with benign breast disease diagnosed in two breast clinics between 1976 and 1979 was carried out to analyse the relationship between progestogen use and the risk of breast cancer. The follow-up accumulated 12,462 person-years. The risk of breast cancer was estimated using a Poisson regression analysis on person-time data and the proportional hazards model. In the latter analysis, cumulated progestogen use and age were considered as time-varying covariables and adjustment was performed on the main risk factors for breast cancer. Neither overall progestogen use nor the duration of use was found to be significantly associated with the risk of breast cancer. When progestogens were classified into two categories according to their hormonal potency (19-nortestosterone derivatives vs other progestogens), 19-nortestosterone derivative use was found to be significantly associated with a lower risk of breast cancer. In the adjusted model, the corresponding risk of breast cancer was 0.48 (95% confidence interval 0.25-0.90). In addition, there was a linear trend in the decrease of the relative risk of breast cancer with the duration of use (P = 0.02). These results do not support the hypothesis that progestogens might increase the breast cancer risk. They suggest, instead, that treatment with 19-nortestosterone derivatives might have a beneficial effect on the risk of breast cancer in women with benign breast disease.

[Hormone therapy of menopause and risk of breast cancer. Polemics and controversies]

The risk/benefit ratio of hormone replacement therapy in the post-menopause period remains controversial due to the risk of breast cancer and the effects of progesterone on mammary tissues. We analyzed the epidemiological data available to evaluate the risk of breast cancer in subjects taking replacement hormones. Oestrogen prescribed alone has not been reported to increase the relative risk of breast cancer compared with subjects not taking hormone therapy. Only elevated levels of conjugated oestrogens have been found to increase the relative risk although sufficient data is not available for an analysis of long-term effects. Combination therapy was reported to have a protective effect in one study but the results have never been reproduced. Other studies have found no significant increase in the risk of breast cancer. Long-term results in subjects on progesterone replacement have not revealed any protector effect. Animal models have shown that progesterone opposes the proliferative effect of oestrogens on mammary tissue and would suggest that progesterone has a protective action. Most in vitro studies on human mammary tissue suggest that progesterone has an antioestrogenic effect on epithelial tissues. The epidemiological data available leads to the conclusion that the therapeutic regimen recommendations currently put forward remain valid. Further large long-term prospective randomized trials are needed to definitely answer the remaining questions.

A risk-benefit appraisal of transdermal estradiol therapy

Estrogen replacement therapy (ERT) is very effective in relieving many menopausal symptoms such as hot flushes, night sweats, urogenital atrophy and psychological disturbances. Moreover, it is effective in the prevention of postmenopausal osteoporosis and has a favourable effect on some risk factors for cardiovascular disease in the long term, via several mechanisms including mediating effects on the lipid profile. Most of these beneficial effects are maintained with transdermal estradiol therapy, involving the use of a cutaneous delivery system attached to the skin which delivers a controlled rate of estradiol over a period of up to 4 days. However, the clear demonstration of a favourable effect on some risk factors for cardiovascular disease remains to be established. Transdermal administration of estradiol appears to be at least as effective as oral conjugated estrogen therapy on most of the end-points which have been evaluated, but allows a lower dose to be used, avoiding some of the metabolic adverse effects experienced with oral treatment. Endocrinological adverse effects, such as breast tenderness, breakthrough bleeding and fluid retention, are similar in both treatments, and can be minimised by dose adjustments in most cases. The most common adverse effects related to transdermal therapy are local skin reactions at the site of application. These are usually mild and transient in nature, and can be overcome by changing the site of application. Serious risks of transdermal therapy appear to be the same as those for other forms of ERT, namely an increased risk of endometrial hyperplasia and cancer with estrogen therapy alone. However, combination therapy involving the sequential administration of a progestogen has been shown to substantially reduce the risk of endometrial proliferation. The potential increased risk of breast cancer has been controversial and appears to be minimal with ERT. The role of progestogens on breast cancer risk remains controversial, but the data to date do not indicate any significant change in risk when progestogens are added to ERT.