A new approach to estrogen-free contraception based on progesterone receptor blockage by mid-cycle administration of ethyl norgestrienone (R 2323)

Determination of the metabolites of gestrinone in human urine by high performance liquid chromatography, liquid chromatography/mass spectrometry and gas chromatography/mass spectrometry

Gestrinone was studied by high performance liquid chromatography (HPLC) for screening and by gas chromatography/mass spectrometry (GC/MS) for confirmation. When the chromatograms of blank, spiked urine and dosed urine were compared by HPLC, two unknown metabolites were found and these were excreted as the conjugated forms. Metabolites 1 and 2 were tested by LC/MS and LC/MS/MS and both had parent ions at m/z 325. The fragment ion of metabolite 1 was at m/z 263 and ions for metabolite 2 were m/z 307 [MH - H(2)O](+), 289, 279 and 241. LC/MS/MS of m/z 263 as the parent ion of metabolite 1 gave fragment ions at m/z 245 and 217, which were assumed to be [263 - H(2)O](+) and [235 - H(2)O](+), respectively. The trimethylsilyl (TMS)-enol-TMS ether derivative of gestrinone displayed three peaks in its GC/MS chromatogram, formed by tautomerism.

Determination and excretion study of gestrinone in human urine by high performance liquid chromatography and gas chromatography/mass spectrometry

Gestrinone was studied by HPLC for screening and by GC/MS for confirmation. Three unknown peaks were found by HPLC which are probably the metabolites of gestrinone, and conjugated gestrinone in dosed human urine. The metabolites and gestrinone were excreted as the conjugated forms. The total amounts of metabolite 1 and conjugated gestrinone, recovered after 48 h, were 0.20 and 0.32 mg, respectively. When metabolite 1 was tested by LC/MS and LC/MS/MS, the parent ion was m/z 327, [MH](+), and fragment ions were seen at m/z 309 [MH - H(2)O](+), 291 [MH - 2H(2)O](+), 283, 263 and 239. The TMS-enol-TMS ether derivative of gestrinone has three peaks in the GC/MS chromatogram formed by tautomerism. The reproducibility of the derivatization method was stable and recoveries were over 87% when spiked into blank urine.

Clinical, endocrine, and metabolic effects of two doses of gestrinone in treatment of pelvic endometriosis

OBJECTIVE

Our purpose was to determine and compare the efficacy and hormonal and metabolic effects of 1.25 mg with 2.5 mg of gestrinone given twice a week in the treatment of mild and moderate pelvic endometriosis.

STUDY DESIGN

A phase II, prospective, randomized, double-blind study involving 11 patients given gestrinone 1.25 mg (five patients) or 2.5 mg (six patients) orally twice a week for 24 weeks was performed. Revised American Fertility Society scores were determined by laparoscopy before and at the end of treatment. Serum hormone (free thyroxine, free testosterone, estradiol, progesterone, follicle-stimulating hormone, luteinizing hormone), sex hormone binding globulin, and lipid concentrations were measured before, throughout, and for 6 months after treatment. Quantitated computerized tomography of thoracic 12 through lumbar 4 vertebral bodies were determined before, at the end of, and 6 months after treatment.

RESULTS

Gestrinone 2.5 mg significantly reduced the endometriosis implant score from 10.3 +/- 2.8 to 3.8 +/- 0.8 (p = 0.05). Both doses significantly reduced serum progesterone and sex hormone binding globulin levels. Estradiol, free testosterone, free thyroxine, follicle-stimulating hormone, and luteinizing hormone levels were not significantly affected. Spinal bone increased significantly by 7.1% with 2.5 mg but lost significantly by 7.1% with 1.25 mg gestrinone; these changes had not reversed completely 6 months after stopping treatment.

CONCLUSIONS

In mild to moderate pelvic endometriosis 2.5 mg of gestrinone twice a week was more effective and had a more positive effect on bone mass than did 1.25 mg of gestrinone.

Prostaglandins and progesterone receptor antagonists in human fertility regulation

Anti-progesterone medicines have now been extensively studied for human fertility regulation. The combination of the anti-progesterone Mifepristone with prostaglandin analogues such as Gemeprost and Misoprostol have been used in several European centres for medical abortion. Used before nine weeks gestation, these medicines have similar efficacy to surgical abortion. In addition, administration of progesterone antagonists within five days of unprotected intercourse appear effective in pregnancy prevention. Anti-progesterone medicines are not currently available in Australia. The introduction of progesterone receptor antagonists and modern prostaglandins would save approximately $10,000,000 per year to the Australian Health Budget. Furthermore, the introduction of progesterone receptor antagonists for emergency contraception would have even greater financial and emotional savings for Australian women. In Australia, when known carcinogens can be purchased over the counter, it is surely time for Australians to consider effective emergency contraception bought over the counter.

Multicentre study of gestrinone in cyclical breast pain

Although the aetiology of cyclical mastalgia is poorly understood, the consistent finding of an increased prolactin stimulation response probably due to oestrogen dominance has led to the use of treatment with prolactin-lowering drugs and antioestrogens. The efficacy and safety in cyclical mastalgia of gestrinone, which has androgenic, anti-oestrogenic, and antiprogestagenic properties, were investigated in a multicentre study. In a double-blind randomisation procedure, 72 patients were allocated placebo and 73 treatment with gestrinone (2.5 mg twice a week) for 3 months. The patients recorded the severity of breast pain on a visual analogue scale before and during treatment and scored other breast symptoms as not present (0), mild (1), moderate (2), or severe (3). The gestrinone group had significantly greater reductions than the placebo group in breast pain score at months 1, 2, and 3 of treatment (mean reduction 59.5 [SD 22.6] to 11.7 [17.0] vs 58.2 [17.6] to 36.7 [23.0] at month 3; p less than 0.0001). All six breast symptoms had lower scores in the gestrinone than in the placebo group by the end of treatment. In a subset of 30 participants (15 from each group), serum concentrations of oestradiol, progesterone, and tri-iodothyronine were significantly lower than baseline after 3 months of gestrinone, but concentrations of luteinising hormone, follicle-stimulating hormone, prolactin, thyroid-stimulating hormone, and thyroxine did not change. 41% of gestrinone-treated and 14% of placebo-treated patients reported at least one side-effect; most of these were androgen-mediated. 11 placebo-treated patients and 4 on gestrinone discontinued treatment. Thus, gestrinone was very effective in the treatment of cyclical mastalgia and was well tolerated.

Gestrinone versus danazol in the treatment of endometriosis

Thirty-nine infertile patients with laparoscopic diagnosis of endometriosis were allocated randomly to treatment with gestrinone 2.5 mg twice weekly (20 patients) or danazol 600 mg/day (19 patients) for 6 months. If amenorrhea was not obtained after 1 month of treatment, the gestrinone dose was increased to 2.5 mg three times a week (7 patients) and the danazol dose to 800 mg/day (2 patients). One month after the end of the treatment, a repeat laparoscopy was performed only in the women who agreed (7 of the gestrinone treated group, 9 of the danazol group). All of the patients were followed for at least 12 months after the end of the treatment, during which time they attempted to conceive. There was a marked improvement of pain symptoms during the treatment in the patients of both groups. The repeat laparoscopy did not reveal significant differences between the two groups in the reduction of the disease extent. Eighteen months after treatment suspension, the cumulative pregnancy rate was 33% in the patients treated with gestrinone and 40% in those treated with danazol. Pain symptoms recurred during the follow-up in 57% of the gestrinone and 53% of the danazol group. The side effects were more frequent and severe with the danazol treatment, whereas those caused by gestrinone were mostly weight gain and acne. The results of this study suggest that gestrinone is as effective as danazol in the treatment of infertility associated with endometriosis and is better tolerated.

Anti-progesterones: background and clinical physiology

The development of anti-progesterones has provided a probe to examine the role of progesterone both in the normal cycle and in pregnancy. The most widely used of these agents, mifepristone, appears to act both directly at the endometrial progesterone receptor, and centrally by reducing circulating gonadotrophin concentrations. In addition, ovarian steroidogenesis may be modified. The clinical application of these agents for the interruption of pregnancy will be considered in the following chapters.

Impact of gestrinone on the course of asymptomatic endometriosis

A new drug, gestrinone, was subjected to the first double blind, randomised placebo controlled trial of any treatment of endometriosis. The disease deteriorated in eight (47%) of the 17 patients prescribed placebo (95% confidence limits 23% and 71%) compared with none of the 18 patients prescribed gestrinone (p = 0.002). There was a difference in elimination of the endometriosis in the gestrinone group compared with placebo but this was not statistically significant (p = 0.057). There was a significant difference in improvement of the disease in the gestrinone group compared with placebo (p = 0.004), confirming that gestrinone is an effective treatment of endometriosis. Endometriosis deteriorates in at least 23% of patients; as it is impossible to predict in whom this will happen, treatment appears to be warranted in all cases.

Effect of gestrinone in endometriosis tissue and endometrium

The effects of gestrinone (R 2323) on endometrial and endometriosis tissue concentrations of cytosol estrogen and progestin receptors and the activity of 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) were investigated in 11 patients operated on because of suspected external endometriosis. Serum concentrations of luteinizing hormone, follicle-stimulating hormone, estradiol (E2), progesterone, testosterone (T), and sex-hormone-binding globulin (SHBG) were also investigated. After one control cycle, the patients received 2.5 mg of oral gestrinone twice weekly from the fifth day of the first treatment cycle until the eighth day of the second treatment cycle, the day of operation being day 10. Treatment with gestrinone decreased serum concentrations of T during the second treatment cycle and effected a major decrease in SHBG during both treatment cycles, resulting in highly increased free T and free E2 indices. The effects of gestrinone on the endometrium, a decrease in estrogen and progestin receptors, and induction of 17 beta-HSD are characteristic progestin actions. These parameters remained unchanged in endometriosis tissue. Our data indicate that gestrinone has effects that are typical of androgens and progestins in patients with endometriosis.

Induction of menstruation by an antiprogesterone steroid (RU 486) in primates: site of action, dose-response relationships, and hormonal effects

The antiprogesterone compound RU 486 (17 beta-hydroxy-11 beta-[4-dimethylaminophenyl]-17 alpha-[ 1-propynyl]estra-4,9-dien-3-one; Roussel-Uclaf, Paris, France) was used to induce menstruation in a randomized controlled trial. Castrated adult female cynomolgus monkeys (n = 17) received sequential subcutaneous Silastic capsules of estradiol or progesterone over a 49-day regimen which stimulated the steroidal milieu of the fertile ovarian/menstrual cycle. RU 486 was injected at 10.0, 1.0 to 3.0, or 0.1 mg/kg from days 31 to 34 of this protocol. At all concentrations tested, menstruation followed RU 486 injection within 48 hours and persisted through 72 hours. No bleeding followed placebo injections. All monkeys that menstruated after RU 486 administration also manifested vaginal bleeding after removal of exogenous steroid treatments. No changes in daily serum follicle-stimulating hormone, luteinizing hormone, prolactin, or serum and urinary free cortisol accompanied RU 486 treatment. We conclude that (1) RU 486 promptly induces menstruation by a local action upon the endometrium; (2) familiar endometrial proliferation and withdrawal bleeding can redevelop after exposure to this compound; (3) no effects of RU 486 on serum cortisol or pituitary gonadotropins were noted; and (4) extensive combination therapy with estrogen and progesterone causes mild hyperprolactinemia.

Treatment of endometriosis with gestrinone (R-2323), a synthetic antiestrogen, antiprogesterone

Twenty patients with endometriosis diagnosed by laparoscopy were treated with the antiestrogen, antiprogesterone gestrinone (R-2323) for 6 to 8 months. The drug was administered in a dose of 5 mg twice weekly. According to the American Fertility Society's classification of endometriosis, five patients were classified as having mild (Stage I), eight as having moderate (Stage II), and seven as having severe endometriosis (Stage III). All patients became amenorrheic at the end of the second month of treatment, and symptomless at the end of the third month. Of nine women who had the potential and the desire to conceive, three conceived within 3 months after termination of treatment. Two more became pregnant within 1 year, and another, 14 months after termination of treatment. Five pregnancies progressed to term. One patient aborted. Two of the three women who did not conceive had subfertile husbands. Major side effects recorded were seborrhea and acne, which subsided after discontinuation of therapy. Treatment of endometriosis with gestrinone offers the advantage of effective clearing of lesions with relatively low dosage and frees the patient from the daily administration of drugs required by similar conservative hormonal therapies.

Conservative treatment of uterine leiomyoma with the antiestrogen antiprogesterone R-2323

The case reported here shows how adequate conservative therapy of the antiestrogen R-2323 saved a uterus in a woman of child-bearing age who suffered a uterine leiomyoma. The patient's fertility was restored, and a twin pregnancy is currently in progress.

Action of midcycle contraceptive (R 2323) on the human endometrium

Over 2,148 cycles of midcycle oral administration of R 2323 (50 mg. per day on Days 15,16, and 17), the authors recorded a drug-failure pregnancy rate of 5 per cent and an unusually regular cycle length of 28 +/- 2 days. During this trial, endometrial biopsies obtained in the luteal phase were examined by light and electron microscopy and compared to pretreatment biopsies. Light microscopy indicated a weakly secretory endometrium suggestive of some, albeit low, progesterone impregnation. Ultrastructural examination revealed deleterious changes in the development of the nucleolar channel system and giant mitochondria and a delay in the migration of glycogen granules. This low progesterone impregnation could be explained either by a direct effect of R 2323 on cell ultrastructure or by interference with progesterone availability. It would appear that R 2323 acts as a temporary substitute for progesterone at the receptor level but that it does not induce all the biological manifestations of this hormone, in particular, the endometrial changes required for implantation.

Antiprogesterone effect and midcycle (periovulatory) contraception

Based on the sequential changes of hormones in plasma and of progesterone binding sites in the uterus, it is suggested to give once a month, at midcycle (around ovulation), either progesterone itself or a parent compound binding to progesterone receptor. The aim is an antiprogesterone effect occurring presumably through a decrease of receptor functioning ultimately expressed some days later by lack of implantation.