- Non-childbearing potential defined as pre-menopausal females with a documented tubal ligation or hysterectomy; or postmenopausal defined as 12 months of spontaneous amenorrhea and confirmed by screening follicle stimulating hormone (FSH) > 40 MlU/ml and estradiol < 40 pg/ml or <140 pmol/L.. Females on hormone replacement therapy (HRT) must discontinue HRT and their post-menopausal status confirmed as per above tests prior to study enrollment. For most forms of HRT, at least 2-4 weeks will elapse between the cessation of therapy and the blood draw; this interval depends on the type and dosage of HRT. Following confirmation of their post-menopausal status, they are not allowed to use HRT during the study.