 - Females of childbearing potential who: a. had unprotected sexual intercourse within 30 days before study entry and who do not agree to use a highly effective method of contraception eg, total abstinence, an intrauterine device, a double-barrier method such as condom plus diaphragm with spermicide, a contraceptive implant, an oral contraceptive, or have a vasectomized partner with confirmed azoospermia throughout the entire study period or for 28 days after study drug discontinuation. Females using hormonal contraceptives containing levogesterol must be on another form of contraception as well. b. Are currently abstinent, and do not agree to use a double-barrier method as described above or refrain from sexual activity during the study period or for 28 days after study drug discontinuation. c. Are using hormonal contraceptives but are not on a stable dose of the same hormonal contraceptive product for at least 4 weeks before dosing and who do not agree to use the same contraceptive during the study or for 28 days after study drug discontinuation. NOTE: All females will be considered to be of childbearing potential unless they are postmenopausal amenorrheic for at least 12 consecutive months, in the appropriate age group, and without other known or suspected cause or have been sterilized surgically i.e., bilateral tubal ligation, total hysterectomy, or bilateral oophorectomy, all with surgery at least 1 month before dosing. 