Phase II Study of Oral Antineoplastons A10 and AS2-1 in Women With Advanced Breast Cancer

DISEASE CHARACTERISTICS: Histologically confirmed stage IV breast cancer that is unlikely to respond to existing therapy and for which no curative therapy exists Failed prior standard therapy Measurable disease by MRI or CT scan Tumor must be at least 2 cm in the lymph nodes in the head, neck, axillary, inguinal, or femoral areas and at least 0.5 cm in other locations Hormone receptor status: Not specified PATIENT CHARACTERISTICS: Age: 18 and over Sex: Female Menopausal Status: Not specified Performance status: Karnofsky 60-100% Life expectancy: At least 2 months Hematopoietic: WBC at least 2,000/mm^3 Platelet count at least 50,000/mm^3 Hepatic: Bilirubin no greater than 2.5 mg/dL SGOT/SGPT no greater than 5 times upper limit of normal No hepatic failure Renal: Creatinine no greater than 2.5 mg/dL No renal failure Cardiovascular: No chronic heart failure No uncontrolled hypertension Pulmonary: No severe lung disease Other: Not pregnant or nursing Fertile patients must use effective contraception during and for 4 weeks after study participation No serious medical or psychiatric disorders No active infections No other serious concurrent disease No serious malabsorption syndromes PRIOR CONCURRENT THERAPY: Biologic therapy: Recovered from prior immunotherapy At least 4 weeks since prior immunotherapy, except in patients with disease progression during or after initial therapy Chemotherapy: Recovered from prior chemotherapy At least 4 weeks since prior chemotherapy (6 weeks for nitrosoureas), except in patients with disease progression during or after initial therapy Endocrine therapy: Recovered from prior hormonal therapy At least 12 weeks since prior hormonal therapy, except in patients with disease progression during and after initial therapy Concurrent corticosteroids for peritumoral edema allowed Radiotherapy: At least 8 weeks since prior radiotherapy and recovered Patients with multiple tumors who have received radiotherapy to some, but not all, tumors may be admitted earlier than 8 weeks Surgery: Recovered from any prior surgery No prior extensive stomach or intestinal surgery Other: Prior cytodifferentiating agents allowed No prior antineoplaston therapy No other concurrent therapy for metastatic breast cancer