Efficacy Trial of CDB 2914 for Emergency Contraception

Objective: To compare the efficacy, safety and tolerance of a 50 mg dose of a new antiprogestin, CDB-2914 with a 0.75 mg bid dose of levonorgestrel as emergency contraception Design: Multicenter, randomized, double blind Phase II study to compare a 50 mg dose of CDB-2914 to a 0.75 mg bid dose of levonorgestrel as emergency contraception Subjects are randomized to receive a one-time treatment with either one dose of 50 mg CDB-2914 (followed 12 hours later by a placebo) or 2 doses of 0.75 mg of levonorgestrel with follow-up visits at 5-7 days after expected onset of menses and another visit at 12-14 days after expected onset of menses (if needed) The primary aim is to evaluate the efficacy of CDB-2914 used by subjects as an emergency postcoital contraceptive in comparison to a group of subjects receiving levonorgestrel.