Clinical trials with RU 486 (mifepristone): an update

This paper reviews much of the clinical data obtained with the antiprogestin RU 486 (mifepristone) in the fields of obstetrics and gynecology. To interrupt early pregnancy (less than 50 days of amenorrhea) RU 486 as a single dose of 600 mg followed 36-48 hours later by a prostaglandin derivative, constitutes an alternative to vacuum aspiration or dilatation and curettage (D and C). All three methods have comparable efficacy, provided that they are performed in centers with adequate medical facilities. RU 486 is the first antiprogestational steroid available for clinical purposes. Its pharmacological properties have been reviewed in detail elsewhere (1,2). The present paper reviews the main clinical data obtained during trials monitored by Roussel Uclaf.