Since the discovery of the antiprogestin mifepristone, hundreds of similar compounds have been synthesized, which can be grouped in a large family of progesterone receptor ligands. This family includes pure agonists such as progesterone itself or progestins and, at the other end of the biological spectrum, pure progesterone receptor antagonists (PA). Selective progesterone receptor modulators (SPRM) have mixed agonist-antagonist properties, and occupy an intermediate position of the spectrum. These compounds have numerous applications in female health care. Mifepristone is used to terminate pregnancy, and as such is commercially available in many countries. The negative abortion-related image of mifepristone has clearly limited the involvement of the major pharmaceutical companies in the development of PA and SPRM. Many PA and SPRM display direct antiproliferative effects in the endometrium, although with variable actions which seem product- and dose-dependent. This property justifies their use in the treatment of myomas and endometriosis. PA also suppress late follicular development, block the LH surge and retard endometrial maturation, which renders them potential estrogen-free contraceptive drugs. SPRM such as asoprisnil are not as effective in blocking the LH surge and appear to target the endometrium directly and produce amenorrhoea. Interestingly, clinical data show that treatment with these compounds is not associated with hypo-estrogenism and bone loss. The potential clinical applications of these compounds cover a broad field and are very promising in major public health areas. These include emergency contraception, long-term estrogen-free contraception (administered alone, or in association with a progestin-only pill to improve bleeding patterns), myomas (where they induce a marked reduction in tumour volume and produce amenorrhoea) and endometriosis. Further developments might also include hormone replacement therapy in post-menopausal women, as well as the treatment of hormone-dependent tumours.

No abstract

The possibility that meningioma growth may be related to female sex hormone levels is suggested by several lines of evidence. Meningiomas are twice as common in women as in men, have been observed to wax and wane with pregnancy, and are positively associated with breast cancer. A physiological explanation for these phenomena is provided by the finding of steroid hormone receptors in meningiomas. However, unlike breast cancer, meningiomas are much more commonly positive for progesterone receptors than for estrogen receptors. The authors initiated a study on long-term oral therapy of unresectable meningiomas with the antiprogesterone mifepristone (RU486). Fourteen patients received mifepristone in daily doses of 200 mg for periods ranging from 2 to 31+ months (greater than or equal to 6 months in 12 patients). Five patients have shown signs of objective response (reduced tumor measurement on computerized tomography scan or magnetic resonance image, or improved visual field examination). Three have also experienced subjective improvement (improved extraocular muscle function or relief from headache). The side effects of long-term mifepristone therapy have been mild. Fatigue was noted in 11 of the 14 patients. Other side effects included hot flashes in five patients, gynecomastia in three, partial alopecia in two, and cessation of menses in two. Long-term therapy with mifepristone is a new therapeutic option that may have efficacy in cases of unresectable benign meningioma.

No abstract

A patient with Cushing's syndrome due to ectopic ACTH secretion was treated successfully with the new glucocorticoid antagonist RU 486 [17 beta-hydroxy-11 beta-(4-dimethylamino phenyl) 17 alpha-(1-propynyl)estra-4,9-dien-3-one]. This compound is a 19-nor steroid with substitutions at positions C11 and C17 which antagonizes cortisol action competitively at the receptor level. Oral RU 486 was given in increasing doses of 5, 10, 15, and 20 mg/kg . day for a 9-week period. Treatment efficacy was monitored by assessment of clinical status and by measuring several glucocorticoid-sensitive variables, including fasting blood sugar, blood sugar 120 min after oral glucose administration, and plasma concentrations of TSH, corticosteroid-binding globulin, LH, testosterone-estradiol-binding globulin, and total and free testosterone. With therapy, the somatic features of Cushing's syndrome (buffalo hump, central obesity, and moon facies) ameliorated, mean arterial blood pressure normalized, suicidal depression resolved, and libido returned. All biochemical glucocorticoid-sensitive parameters normalized. No side-effects of drug toxicity were observed. We conclude that RU 486 may provide a safe, well tolerated, and effective medical treatment for hypercortisolism.