4. Subjects and their partners must be willing to avoid pregnancy during the study and until 1 month after the last study drug administration. Males with female partners of childbearing potential and female subjects of childbearing potential must therefore be willing to use adequate contraception such as, intra uterine device, diaphragm, or condom, for the duration of the study. For the purposes of this study, childbearing potential is defined as: "All female subjects unless they are post- menopausal for at least two years, are surgically sterile or sexually inactive"