 28. Patients who are sexually active and unwilling to use a medically acceptable method of contraception e.g. such as implants, injectables, combined oral contraceptives, some intrauterine devices or vasectomized partner for participating females during the trial and for at least three months after end of active therapy Contraception in patients with preserved reproductive capacity, patients will be considered to be of childbearing potential unless surgically sterilised by hysterectomy or bilateral tubal ligationsalpingectomy, or post-menopausal for at least two years. 