- Female patients of childbearing potential must have a negative urine or serum pregnancy test prior to the first dose of trial treatment; they must also agree to two barrier methods or a barrier method plus a hormonal method, or agree to abstain from heterosexual activity, for the course of the study through 120 days after the last dose of trial treatment; females who have been surgically sterilized or are free from menses for > 1 year (postmenopausal) may enroll