DISEASE CHARACTERISTICS:

• Histologically confirmed advanced breast cancer that is refractory or unlikely to respond to hormonal therapy AND failed at least 1 prior chemotherapy regimen
• Symptomatic lymphangitic pulmonary dissemination allowed
• Extensive visceral metastasis allowed
• Patients who are refractory or who have failed to respond after at least 8 weeks of methotrexate or a methotrexate-containing regimen are not eligible
• Measurable disease
• No bone metastases
• Hormone receptor status:
• Estrogen receptor negative

PATIENT CHARACTERISTICS:

Age:

• Postmenopausal

Sex:

• Female

Menopausal status:

• Postmenopausal

Performance status:

• Karnofsky 60-100%

Life expectancy:

• At least 3 months

Hematopoietic:

• WBC at least 3,000/mm^3
• Platelet count at least 100,000/mm^3

Hepatic:

• Bilirubin no greater than 2.5 mg/dL
• SGOT no greater than 2 times normal
• Blood ammonia normal
• No hepatic failure

Renal:

• BUN less than 60 mg/dL
• Creatinine no greater than 2.5 mg/dL
• Creatinine clearance greater than 60 mL/min
• No chronic renal failure

Cardiovascular:

• No severe heart disease

Pulmonary:

• No severe lung disease

Other:

• No serious active infections or fever
• No other concurrent serious disease
• No prior or concurrent secondary malignancies within the past 2 years
• Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• At least 4 weeks since prior immunotherapy and recovered
• No concurrent biologic therapy for metastatic breast cancer

Chemotherapy:

• See Disease Characteristics
• At least 4 weeks since prior cytotoxic chemotherapy and recovered
• No other concurrent chemotherapy for metastatic breast cancer

Endocrine therapy:

• See Disease Characteristics
• At least 4 weeks since prior hormonal therapy and recovered
• No concurrent hormonal therapy for metastatic breast cancer

Radiotherapy:

• At least 4 weeks since prior radiotherapy and recovered
• No concurrent radiotherapy for metastatic breast cancer

Surgery:

• Not specified

Other:

• At least 4 weeks since prior participation in experimental clinical trials
• No prior antineoplaston A10 therapy
• No other concurrent treatment for metastatic breast cancer
• No concurrent salicylates, nonsteroidal anti-inflammatory drugs, phenylbutazone, phenytoin, and sulfonamides