 - Men or women 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, condoms for participating males during the trial and for at least three months after end of active therapy; a highly effective method of birth control is defined as one which results in a low failure rate i.e., less than 1 per year when used consistently and correctly; patients will be considered to be of childbearing potential unless surgically sterilized by hysterectomy or bilateral tubal ligationsalpingectomy, or post-menopausal for at least 2 years 