13. Because the effects of chemotherapy on the developing human fetus are potentially harmful, female patients must be one year post-menopausal, surgically sterile, or using an acceptable method of contraception during and continued after the last dose of study medications (oral contraceptives, barrier methods, approved contraceptive implant, long-term injectable contraception, intrauterine device or tubal ligation). Male patients must be surgically sterile or using an acceptable method of contraception during their participation in this study. Contraceptive use will continue for at least four months after the last dose of study medication.