6. Female subjects must have a negative urine pregnancy test at screening AND: be surgically sterile OR postmenopausal for the last three months, OR in a monogamous relation with a male partner who has undergone a documented vasectomy a minimum of 6 months prior to study commencement. All females must agree to continue to use their method of birth control for the duration of the study and for a minimum of one complete menstrual cycle or 28 days following discharge from the study