RATIONALE: Antineoplastons are naturally-occurring substances that may also be made in the laboratory. Antineoplastons may inhibit the growth of cancer cells.

PURPOSE: This phase II trial is studying how well antineoplaston therapy works in treating women with stage IV breast cancer that has not responded to standard therapy.

OBJECTIVES:

• Determine the antitumor activity of antineoplastons A10 and AS2-1 capsules in patients with advanced breast cancer by determining the proportion of women who experience an objective tumor response.
• Evaluate the adverse effects of and tolerance to this regimen in these patients.

OUTLINE: This is an open-label study.

Patients receive oral antineoplaston A10 and antineoplaston AS2-1 6 to 7 times per day.

Treatment continues for at least 6 weeks. Patients achieving complete or partial response may continue on therapy until disease progression or toxic effects occur.

Patients are followed for survival.

PROJECTED ACCRUAL: A total of 20-40 patients will be accrued for this study.

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