 - No treatment with cytotoxic or biologic agents within the 4 weeks prior to beginning treatment on this study 6 weeks for mitomycin or nitrosoureas. At least 4 weeks must have elapsed from any prior surgery, radiation, hormonal or other drug therapy for their cancer. Patients must have fully recovered from the acute toxicities of any prior treatment with cytotoxic drugs, radiotherapy or other anti-cancer modalities returned to baseline status as noted before most recent treatment. Patients with persisting, stable chronic toxicities from prior treatment grade 1 are eligible. 