 9. Negative serum or urine pregnancy test for women within 7 days of receiving the first dose of the study medication for women of childbearing potential. Women will be considered not of childbearing potential and exempt from pregnancy testing if they are either a older than 50 and amenorrheic for at least 12 consecutive months following cessation of all exogenous hormonal treatments, or b have documentation of irreversible surgical sterilization by hysterectomy, bilateral oophorectomy or bilateral salpingectomy, but not tubal ligation. 