Inclusion Criteria

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