Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed soft tissue sarcoma that is not amenable to surgery,
radiotherapy, or combined modality therapy with curative intent

- Stratum I

- Malignant fibrous histiocytoma

- Liposarcoma

- Rhabdomyosarcoma

- Synovial sarcoma

- Malignant paraganglioma

- Fibrosarcoma

- Leiomyosarcoma

- Angiosarcoma including hemangiopericytoma

- Malignant peripheral nerve sheath tumor

- Unclassified sarcoma

- Miscellaneous sarcoma

- Stratum II

- Gastrointestinal stromal tumor

- Previously treated with imatinib mesylate for locally advanced or metastatic
disease and demonstrated disease progression

- The following sarcoma types are excluded:

- Mixed mesodermal tumors of the uterus (and carcinosarcoma)

- Chondrosarcoma

- Malignant mesothelioma

- Neuroblastoma

- Osteosarcoma

- Ewing's sarcoma

- Embryonal rhabdomyosarcoma

- At least one measurable lesion

- Progressive disease after 1 prior anthracycline- and/or alkylating-containing
chemotherapy regimen for locally advanced or metastatic disease

- Clinical evidence of progression within 6 weeks prior to study treatment

- No known or symptomatic CNS metastases

PATIENT CHARACTERISTICS:

Age:

- Over 15

Performance status:

- WHO 0-1

Life expectancy:

- Not specified

Hematopoietic:

- WBC at least 4,000/mm^3

- Platelet count at least 100,000/mm^3

Hepatic:

- Bilirubin no greater than 1.25 times upper limit of normal (ULN)

- SGPT and SGOT no greater than 3 times ULN

- Alkaline phosphatase no greater than 2.5 times ULN

Renal:

- Creatinine no greater than 1.4 mg/dL OR

- Creatinine clearance greater than 65 mL/min

Cardiovascular:

- No prior severe cardiovascular disease

Other:

- Not pregnant

- Negative pregnancy test

- Fertile patients must use effective contraception during and for up to 6 months after
study

- No other prior or concurrent malignancy except adequately treated basal cell skin
cancer or carcinoma in situ of the cervix

- No other severe medical illness

- No psychosis

PRIOR CONCURRENT THERAPY:

Biologic therapy:

- No concurrent biologic response modifiers or immunotherapy

- No concurrent prophylactic hematopoietic growth factors (e.g., filgrastim (G- CSF) or
sargramostim (GM-CSF)

Chemotherapy:

- See Disease Characteristics

- More than 4 weeks since prior chemotherapy and recovered

- Prior adjuvant chemotherapy as first-line treatment allowed provided disease
progressed within 6 months after the completion of chemotherapy

- No prior ecteinascidin 743 (stratum I)

- No other concurrent chemotherapy

Endocrine therapy:

- No concurrent hormonal therapy

Radiotherapy:

- See Disease Characteristics

- Recovered from prior radiotherapy

- No prior radiotherapy to sole measurable lesion

- Concurrent palliative radiotherapy to nontarget lesions allowed at investigator's
discretion

Surgery:

- See Disease Characteristics

- Recovered from prior surgery

Other:

- No other concurrent anticancer therapy (approved or investigational)

- No concurrent participation in any other clinical treatment study

- No other concurrent investigational drugs