Phase II Randomized Study of Methotrexate With or Without Antineoplaston A10 Capsules in Women With Advanced Breast Cancer

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