DISEASE CHARACTERISTICS:

• Histologically confirmed ductal adenocarcinoma of the pancreas

  • Mixed adenocarcinoma tumors eligible provided the predominant invasive component of the tumor is adenocarcinoma

• The following histologic diagnoses are not eligible:

  • Adenosquamous
  • Squamous cell
  • Colloid
  • Islet cell
  • Serous or mucinous cystadenoma or cystadenocarcinoma
  • Carcinoid
  • Small or large cell carcinoma
  • Intraductal oncocytic papillary neoplasms
  • Osteoclast-like giant cell tumors
  • Acinar cell carcinoma
  • Pancreatoblastoma
  • Solid pseudopapillary tumors
  • Undifferentiated small cell carcinoma
  • Nonepithelial tumors (sarcoma, gastrointestinal stromal tumor, lymphoma)
  • Adenocarcinomas of the ampulla, distal bile duct, or duodenum
• Metastatic or locally advanced disease that is refractory to standard therapy OR for which patient refused standard therapy

• Measurable disease defined as ≥ 1 lesion unidimensionally measured as ≥ 20 mm by conventional techniques or ≥ 10 mm by spiral CT scan

  • No nonmeasurable disease only including, but not limited to, the following:

    • Bone lesions
    • Leptomeningeal disease
    • Ascites
    • Pleural or pericardial effusion
    • Inflammatory breast disease
    • Lymphangitis cutis/pulmonis
    • Abdominal masses that are not confirmed and followed by imaging techniques
    • Cystic lesions
• No known active or untreated brain metastases

PATIENT CHARACTERISTICS:

• ECOG performance status 0-1
• WBC ≥ 3,500/mm^3
• Absolute neutrophil count ≥ 1,500/mm^3
• Hemoglobin ≥ 9 g/dL
• Platelet count ≥ 90,000/mm^3
• Creatinine ≤ 2.0 mg/dL
• Bilirubin ≤ 2 mg/dL
• ALT and AST ≤ 5 times upper limit of normal (ULN)
• Alkaline phosphatase ≤ 5 times ULN
• No active infection
• No uncontrolled medical condition that would potentially increase the risk of toxicities or complications of study therapy
• No gastrointestinal tract disease resulting in an inability to take oral medication or a requirement for IV alimentation
• No active peptic ulcer disease
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception during and for 4 weeks after completion of study treatment
• No other malignancy within the past 5 years except for nonmelanomatous skin cancer, superficial bladder cancer, or carcinoma in situ of the cervix
• HIV negative

• No active autoimmune disease or prior autoimmune disease requiring medical treatment with systemic immunosuppressants including any of the following:

  • Inflammatory bowel disease
  • Systemic vasculitis
  • Scleroderma
  • Psoriasis
  • Multiple sclerosis
  • Hemolytic anemia or immune thrombocytopenia
  • Rheumatoid arthritis
  • Systemic lupus erythematosus
  • Sjögren's syndrome
  • Sarcoidosis
  • Asthma or chronic obstructive pulmonary disease that does not require systemic corticosteroids or routine use of inhaled steroids allowed
• No known or suspected hypersensitivity to sargramostim (GM-CSF), cyclophosphamide, pentastarch, corn, or DMSO
• No prior severe infusion reaction (> grade 3) to a monoclonal antibody

PRIOR CONCURRENT THERAPY:

• See Disease Characteristics
• More than 1 month since prior adjuvant chemotherapy
• More than 4 weeks since prior surgery except for minor procedures (e.g., dental work, skin biopsy) and biliary stent placement
• No prior surgical procedures affecting absorption
• More than 4 weeks since prior radiotherapy
• More than 1 month since prior participation in an investigational new drug study
• No unresolved chronic toxicity (except alopecia) from prior anticancer therapy
• More than 28 days since prior systemic steroids

• No concurrent systemic steroids or immunosuppressive drugs

  • Topical, inhaled, and intra-articular steroids allowed
• No other concurrent anticancer vaccine therapy
• No other concurrent chemotherapy, immunotherapy, radiotherapy, gene therapy, biologic therapy, or investigational therapy