- Females of child-bearing potential and males must agree to use highly effective contraceptive precautions during the trial and up to 12 months following the last dose of study treatment; a highly effective method of birth control is defined as one that results in a low failure rate (that is, < 1% per year) when used consistently and correctly, such as implants, injectables, combined oral contraceptives, some intrauterine contraceptive devices (IUDs), sexual abstinence, or a vasectomized partner