9. Women of childbearing age (women whose last menstrual period was more than one year before study enrolment and those who have had tubal ligation or a hysterectomy performed are excluded) must have obtained a negative result for the pregnancy test conducted in the screening phase and must agree to use a medically acceptable contraceptive method throughout the duration of the study. Men participating in the study must also agree to use a medically acceptable contraceptive if they have intercourse with women of childbearing age;