Polyglutamate Camptothecin in Treating Patients With Advanced Cancer

DISEASE CHARACTERISTICS: * Histologically confirmed advanced malignancy * No active brain metastases (as indicated by clinical symptoms, cerebral edema, or progressive tumor growth) that have been unstable for at least 8 weeks PATIENT CHARACTERISTICS: Age * 18 and over Performance status * ECOG 0-2 Life expectancy * At least 12 weeks Hematopoietic * Absolute neutrophil count at least 1,500/mm\^3 * Platelet count at least 100,000/mm\^3 * Hemoglobin at least 9 g/dL Hepatic * Bilirubin no greater than 1.5 times upper limit of normal (ULN) * AST and ALT no greater than 2.5 times ULN (5 times ULN if liver metastases are present) Renal * Creatinine no greater than 1.5 times ULN * No history of hemorrhagic cystitis * No history of microscopic hematuria associated with drug therapy or radiotherapy or of unknown origin Cardiovascular * No significant cardiac disease Other * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception * Able to comply with study schedule and assessments * No other significant nonmalignant systemic disease * No active infection * No other condition that would in the investigator's opinion make the patient an inappropriate study candidate PRIOR CONCURRENT THERAPY: Biologic therapy * Not specified Chemotherapy * No more than 3 prior chemotherapy regimens * More than 4 weeks since prior chemotherapy Endocrine therapy * Not specified Radiotherapy * More than 4 weeks since prior definitive radiotherapy (except for palliative reasons to sites of nonmeasurable disease, in patients with measurable disease at baseline) * Concurrent palliative radiotherapy allowed Surgery * More than 4 weeks since prior major thoracic or abdominal surgery Other * Recovered from prior therapy (except alopecia or stable grade 1 neuropathy) * More than 4 weeks since prior investigational agents * No prior myeloablative therapy