RATIONALE: Vaccines may make the body build an immune response to kill tumor cells.

PURPOSE: Randomized phase II trial to compare the effectiveness of two different vaccines in treating patients who have cancer of the gastrointestinal tract.

OBJECTIVES:

• Determine whether immunization with carcinoembryonic antigen (CEA) peptide 1-6D (CAP 1-6D) emulsified in Montanide ISA-51 adjuvant or dissolved in sargramostim (GM-CSF) can generate CAP 1-6D-specific T cells in patients with CEA-producing adenocarcinomas of gastrointestinal tract origin.
• Determine whether vaccination with CAP 1-6D can generate cytotoxic T cells against CEA-expressing tumors in these patients.
• Determine whether this vaccine can produce antitumor responses in these patients.
• Determine the frequency and severity of toxic effects associated with this vaccine in these patients.

OUTLINE: This is a randomized study. Patients are randomized to 1 of 2 treatment arms.

• Arm I: Patients receive carcinoembryonic antigen peptide 1-6D (CAP 1-6D) emulsified in Montanide ISA-51 adjuvant subcutaneously on day 1.
• Arm II: Patients receive CAP 1-6D dissolved in sargramostim (GM-CSF) intradermally on day 1.

Treatment repeats in both arms every 3 weeks for 6 courses in the absence of disease progression or unacceptable toxicity.

Patients are followed at 3 weeks and then as necessary.

PROJECTED ACCRUAL: A total of 10-36 patients (5-18 per arm) will be accrued for this study within 36 months.

DISEASE CHARACTERISTICS:

• Histologically confirmed stage II, III, or IV adenocarcinoma of the gastrointestinal tract originating in 1 of the following:

  • Esophagus
  • Stomach
  • Pancreas
  • Small intestine
  • Colon or rectum
  • Gall bladder
  • Extrahepatic bile ducts
  • Ampulla of Vater
• Completed standard therapy and at risk of recurrent disease OR has relatively stable metastatic disease and a life expectancy of at least 6 months
• Carcinoembryonic antigen (CEA)-producing tumor as evidenced by detectable blood levels of CEA or positive for CEA on immunohistochemical staining
• HLA-A2+

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Performance status:

• SWOG 0-1

Life expectancy:

• See Disease Characteristics

Hematopoietic:

• WBC at least 4,000/mm^3
• Platelet count at least 100,000/mm^3
• Hemoglobin at least 8 g/dL

Hepatic:

• SGOT or SGPT no greater than 3 times upper limit of normal
• Hepatitis B and C negative

Renal:

• Creatinine no greater than 2.0 mg/dL

Other:

• No other prior malignancy unless currently disease free and off all therapy for that malignancy

  • Early skin cancer allowed
• No AIDS
• HIV negative
• Not pregnant or nursing
• Fertile patients must use effective contraception during and for 30 days after study participation

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• At least 4 weeks since prior immunotherapy

Chemotherapy:

• At least 4 weeks since prior chemotherapy

Endocrine therapy:

• Not specified

Radiotherapy:

• At least 4 weeks since prior radiotherapy

Surgery:

• At least 4 weeks since prior surgery

Other:

• No other concurrent therapy for malignancy