 4. All females must have a negative serum beta human chorionic gonadotropin B-hCG test result and a negative urine pregnancy test result at Screening and Baseline. Females of childbearing potential must agree to use a highly effective method of contraception e.g., abstinence, an intrauterine device IUD, a barrier method such as a condom plus spermicide or condom plus diaphragm with spermicide, a contraceptive implant, an oral contraceptive, or have a vasectomized partner with confirmed azoospermia throughout the entire study period and for 30 days after study drug discontinuation. The only subjects who will be exempt from this requirement are postmenopausal females defined as at least 12 months consecutive amenorrhea, in the appropriate age group, without other known or suspected primary cause or subjects who have been sterilized surgically or who are otherwise proven sterile i.e., bilateral tubal ligation with surgery at least 1 month prior to dosing, hysterectomy, or bilateral oophorectomy with surgery at least 1 month prior to dosing. All women who are of reproductive potential and who are using hormonal contraceptives must have been on a stable dose of the same hormonal contraceptive product for at least 4 weeks prior to dosing and must continue to use the same contraceptive during the study and for 30 days after study drug discontinuation. 