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 patients with colon cancer.

OBJECTIVES:

• Determine the antitumor activity of antineoplastons A10 and AS2-1 in patients with adenocarcinoma of the colon by determining the proportion of patients 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 gradually escalating doses of oral antineoplaston A10 and oral antineoplaston AS2-1 6-7 times a day. If the patient has not achieved a partial or complete response after 3-4 months of treatment, the investigator may discontinue treatment. Patients with stable disease may continue to receive treatment until disease progression or unacceptable toxicity is observed.

Tumors are measured every 4 months during the first 2 years, then every 6 months during years 3 and 4, and yearly during years 5 and 6.

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

DISEASE CHARACTERISTICS:

• Histologically confirmed adenocarcinoma of the colon that is unlikely to respond to existing therapy and for which no curative therapy exists
• Measurable disease by MRI or CT scan
• Metastatic or unresectable disease

PATIENT CHARACTERISTICS:

Age:

• 18 and over

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 serious lung disease, such as chronic obstructive pulmonary disease

Other:

• Not pregnant or nursing
• Fertile patients must use effective contraception during and for 4 weeks after study participation
• No active infection
• No serious malabsorption syndromes
• No other serious concurrent disease

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• At least 4 weeks since prior immunotherapy and recovered

Chemotherapy:

• At least 4 weeks since prior chemotherapy (6 weeks for nitrosoureas) and recovered

Endocrine therapy:

• Concurrent corticosteroids allowed

Radiotherapy:

• At least 8 weeks since prior radiotherapy and recovered (patients with multiple tumors may be admitted earlier)

Surgery:

• No prior extensive stomach or intestinal surgery

Other:

• Prior cytodifferentiating agent allowed
• No prior antineoplaston therapy
• No other concurrent anticancer therapy