- For females of child-bearing potential: ability and willingness to use a highly effective form of contraception (e.g., abstinence from sexual intercourse, surgical sterilisation (of subject or partner) or a double-barrier method of contraception such as either an intra-uterine device (IUD) or an occlusive cap with spermicide, in conjunction with partner's use of a condom) during the study and for a period of at least 48 hours afterwards.