Patients must agree to use adequate contraception (abstinence; hormonal or barrier method of birth control) prior to the study, during the study, and at least six months after completion. Males must agree to use a latex condom during sexual contact with females of childbearing potential while participating in the study and for at least six months following, even if a man has undergone a successful vasectomy. All patients must be counseled at a minimum of every 28 days about pregnancy precautions and risks of fetal exposure as indicated in the consent.