RU 486: how abortion politics have impacted on a potentially useful drug of broad medical application.

ABSTRACT

PIP RU-486 or mifepristone is best known as an antiprogestin and an abortifacient, but it has broad medical applicability. The drug is also a potent blocker of corticosteroid receptors, and it has shown promise in the treatment of breast cancer, inoperable meningioma, and cushing's disease. Cushing's is a model for the symptomatology of aging which may involve enhanced response to corticosteroid. RU-486 has reversed the osteoporosis, thinning of skin, muscle atrophy, obesity, adult onset diabetes, depression, hypertension, and immunosuppression associated with this disease. RU-486 may be of value in aiding cervical dilation, lactation, and the treatment of endometriosis. In addition, breast, bowel, kidney tumors, hepatomas, endometrial cancer, and fibrosarcomas can show corticosteroid dependency, suggesting that RU-486 may have clinical value against inoperable tumors. In a preliminary 1987 phase I study, in estrogen-positive, chemotherapy-refractory breast cancer patients in Montpelier, France, Ru-486 produced objective tumor regression (6 of 22) that was prolonged (3 months) in 4 patients. Clinical relief of bone pain was observed in 7 of 23 patients with a decline in carcinoembryonic antigen (CEA) tumor makers in 8 patients. Growing in vitro data also show that RU-486 can directly inhibit breast cancer cell proliferation. RU-486 has application for HIV infection, based on data that there is a serum factor in AIDS patients that enhances corticosteroid lympholysis. IN addition, the immune restorative action of RU-486 suggests that it could counteract the immunosuppression seen in aging, in cancer, or in viral or stress-related disease, which has recently focused clinical attention on its potential in the treatment of senile dementia and depression. Scientific conferences and workshops are needed to alert scientists, physicians, and the public to the potential medical benefits of this drug.^ieng