Inclusion Criteria: Histological proof of malignant solid tumor that is refractory to standard forms of therapy or for which no known curative therapy exists; Measurable or evaluable disease; At least 6 weeks since prior chemotherapy with nitrosoureas; At least 28 days since prior anticancer therapy and recovered; At least 4 weeks since prior radiation therapy and recovered; Age 18 years or older; SWOG 0-2; Life expectancy of at least 12 weeks; Segmented neutrophils with bands at least 1,500/mm3; Hemoglobin at least 9.0 g/dL and platelet count at least 100,000/mm3; Prothrombin time and partial thromboplastin time no greater than 2.0 times control; INR no greater than 3.0 times control; Concurrent use of coumadin allowed only if dose is stable and prothrombin time and INR is stable; Total serum bilirubin at least 1.5 but no greater than 5.0 times upper limit of normal; SGOT/SGPT no greater than 5 times upper limit of normal; SGOT/SGPT at least 1.5 but no greater than 20.0 times upper limit of normal; Creatinine no greater than 2