Edotecarin in Treating Women With Locally Advanced or Metastatic Breast Cancer That Has Not Responded to Chemotherapy

DISEASE CHARACTERISTICS: * Histologically or cytologically confirmed primary adenocarcinoma of the breast * Locally advanced or metastatic disease * Not amenable to surgery or radiotherapy with curative intent * At least 1 unidimensionally measurable lesion * At least 20 mm by conventional techniques OR 10 mm by CT scan * Not previously irradiated * Meets 1 of the following criteria: * Previously treated with anthracycline and concurrent or sequential taxane therapy * Refractory to the most recent taxane-based chemotherapy, defined as 1 of the following: * Progressive disease during therapy or within 4 months of the last dose with or without documented response for advanced disease * Progressive disease within 6 months of completing taxane-based chemotherapy as neoadjuvant therapy * Resistant to prior chemotherapy, as defined by progressive disease within 6 months of completing prior chemotherapy for advanced disease * No known brain metastases or carcinomatous meningitis\* NOTE: \*Baseline CT scan or MRI of the brain required if there is clinical suspicion of CNS metastases * No spinal cord compression * Hormone receptor status: * Not specified PATIENT CHARACTERISTICS: Age * 18 and over Sex * Female Menopausal status * Not specified Performance status * ECOG 0-1 Life expectancy * Not specified Hematopoietic * Absolute neutrophil count at least 1,500/mm\^3 * Platelet count at least 100,000/mm\^3 * Hemoglobin at least 9.0 g/dL Hepatic * Bilirubin no greater than 1.5 times upper limit of normal (ULN) * SGOT no greater than 2.5 times ULN (5 times ULN if liver involvement secondary to tumor is present) * Albumin at least 3.0 g/dL Renal * Creatinine no greater than 1.5 mg/dL Cardiovascular * LVEF at least 50% or ULN by echocardiogram or MUGA * None of the following within the past 6 months: * Myocardial infarction * Severe or unstable angina * Symptomatic congestive heart failure * Cerebrovascular accident or transient ischemic attack * Deep vein thrombosis or other significant thromboembolic event * No ongoing cardiac dysrhythmias grade 2 or greater * No atrial fibrillation of any grade Pulmonary * No pulmonary embolism within the past 6 months Gastrointestinal * No active inflammatory bowel disease * No partial or complete bowel obstruction * No chronic diarrhea Other * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception * No known HIV positivity * No active infection * No other malignancy within the past 5 years except adequately treated basal cell or squamous cell skin cancer or carcinoma in situ of the cervix * No other severe acute or chronic medical or psychiatric condition or laboratory abnormality that would preclude study participation or confound study results PRIOR CONCURRENT THERAPY: Biologic therapy * No concurrent biological response modifiers * No concurrent immunotherapy * No concurrent sargramostim (GM-CSF) * No other concurrent granulocyte colony-stimulating factors Chemotherapy * See Disease Characteristics * Prior adjuvant chemotherapy allowed * No prior topoisomerase I inhibitors * No more than 2 prior chemotherapy regimens for advanced disease * No prior high-dose chemotherapy that required hematopoietic stem cell rescue * No other concurrent chemotherapy Endocrine therapy * Prior adjuvant hormonal therapy or hormonal therapy for advanced/metastatic disease allowed provided that therapy is discontinued before study entry * No concurrent hormonal therapy Radiotherapy * See Disease Characteristics * No prior radiotherapy to more than 25% of the bone marrow * No concurrent radiotherapy during and for 5 days after study treatment * Palliative radiotherapy allowed provided no more than 20% of the bone marrow is involved Surgery * No coronary/peripheral artery bypass graft within the past 6 months Other * Recovered from prior therapy (except alopecia or neurotoxicity) * At least 4 weeks since any other prior therapy * More than 4 weeks since prior investigational agents * No concurrent enrollment on another clinical trial * No other concurrent approved or investigational anticancer treatment