- not of childbearing potential: defined as postmenopausal for at least 2 years prior to screening defined as amenorrheic for longer than 2 years, age appropriate, and confirmed by a follicle-stimulating hormone level indicating a postmenopausal state, or surgically sterile: defined as bilateral tubal ligation, bilateral oophorectomy or hysterectomy or has a vasectomized partner(s);