- use a highly effective method of contraception throughout the entire duration of the study and for 6 months (6 menstrual cycles) following completion of the last dose of study medication. A highly effective method of contraception is defined as one which result in a low failure rate (that is, less than 1 percent per year) when used consistently and correctly, such as implants, injectables, combined oral contraceptives, some intrauterine devices (IUDs), sexual abstinence or a vasectomized partner. For the purpose of this trial, women of childbearing potential are defined as: All female subjects after puberty unless they are post-menopausal for at least 2 years, or are surgically sterile