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~Duration: A one-time treatment with either CDB-2914 or 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)~Treatment: A one-time treatment with one of the following:~Two doses of 0.75 mg of levonorgestrel to be taken 12 hours apart~One dose of 50 mg CDB-2914 and a second placebo dose to be taken 12 hours later~Study Sites: Multicenter study in the United States~Subjects: Women of reproductive age (at least 18 years) at risk of pregnancy within 72 hours of unprotected coitus~Sample Size: Approximately 811 women will be enrolled in each treatment group to obtain 1540 evaluable subjects~Outcome Evaluations~Primary: To evaluate the efficacy of CDB-2914 used by subjects as an emergency postcoital contraceptive in comparison to a group of subjects receiving levonorgestrel.~Secondary: To compare the tolerability (as measured by vomiting and nausea) of CDB-2914 used by subjects as an emergency postcoital contraceptive with that of a group of subjects receiving levonorgestrel.~Safety/Other: To assess the frequency and intensity of adverse events and the effects on the menstrual cycle of subjects administered CDB-2914 in comparison to subjects given levonorgestrel.
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.