2. Females of childbearing potential must have a negative serum beta human chorionic gonadotropin (β-hCG) at Visit 1 (Screening) and a negative urine pregnancy test prior to starting study drugs (Visit 2). Female subjects of childbearing potential must agree to be abstinent or to use a highly effective method of contraception (eg, condom + spermicide, condom + diaphragm with spermicide, intrauterine devise (IUD), or have a vasectomised partner) for at least one menstrual cycle prior to starting study drug(s) and throughout the longer of either Core Study period or 30 days after the last dose of study drug. Those females using hormonal contraceptives must also be using an additional approved method of contraception (as described previously).