Inclusion Criteria

DISEASE CHARACTERISTICS: Histologically confirmed metastatic breast cancer Bidimensionally
measurable disease No uncontrolled brain metastases or leptomeningeal disease Brain
metastases treated with surgery and/or radiotherapy allowed if neurologic status is stable
two weeks after last dose of dexamethasone Hormone receptor status: Not specified

PATIENT CHARACTERISTICS: Age: 18 and over Sex: Female Menopausal status: Not specified
Performance status: Zubrod 0-2 Life expectancy: At least 3 months Hematopoietic: Platelet
count at least 100,000/mm3 Hemoglobin at least 8 g/dL Absolute neutrophil count at least
1,500/mm3 Hepatic: Bilirubin no greater than 1.2 mg/dL SGPT less than 1.5 times upper
limit of normal Renal: Creatinine no greater than 2.0 mg/dL Cardiovascular: LVEF at least
50% by MUGA No cardiac disease or congestive heart failure Other: Not pregnant or nursing
Negative pregnancy test Fertile patients must use effective contraception No other
concurrent serious illness, psychiatric disorder, or active infection No other prior or
concurrent malignancy within the past 5 years except nonmelanoma skin cancer or carcinoma
in situ of the cervix

PRIOR CONCURRENT THERAPY: Biologic therapy: No prior high-dose chemotherapy followed by
bone marrow transplantation Chemotherapy: See Biologic Therapy At least 3 weeks since
prior chemotherapy and recovered No prior doxorubicin HCl liposome or gemcitabine Prior
neoadjuvant chemotherapy allowed At least 12 months since prior adjuvant
anthracycline-based therapy and no evidence of anthracycline resistance (i.e., developed
progressive disease while receiving adjuvant therapy or within 6 months of completing
adjuvant therapy) Prior mitoxantrone allowed if total dose was no greater than 105 mg/m2
IV bolus or 140 mg/m2 IV continuous infusion Prior doxorubicin allowed if total dose was
no greater than 300 mg/m2 IV bolus or 400 mg/m2 IV continuous infusion No prior
chemotherapy for metastatic disease Endocrine therapy: Prior adjuvant and/or palliative
hormonal therapy allowed Radiotherapy: See Disease Characteristics At least 3 weeks since
prior radiotherapy and recovered Surgery: See Disease Characteristics Prior surgery
allowed Other: At least 3 weeks since prior investigational study Concurrent pamidronate
allowed if bone not the only site of disease