- Or, if of childbearing potential: Agree not to try to become pregnant during the study and for 28 days after the final study drug administration; and have a negative urine or serum pregnancy test at screening; and, if heterosexually active, agree to consistently use 2 forms of highly effective birth control (at least one of which must be a barrier method) starting at screening and throughout the study and for 28 days after the final study drug administration.