10. Patients must not receive any other anti-cancer agents or other investigational agents during the course of this investigation or within 3 weeks prior to study entry. At least 8 weeks must have elapsed since administration of extended radiotherapy or nitrosurea. Evaluable lesions must not have any radiotherapy within 8 weeks of the start of this protocol. Previously irradiated lesions that are used to evaluate tumor response must have shown evidence of an interim increase in size. For patients who have had stem cell transplant, they must have evidence of stable engraftment without the need for significant blood product support or cytokine therapy.