Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically or cytologically confirmed carcinoma arising from the pancreas

- Stage II or III disease, meeting 1 of the following criteria:

- Nonresectable disease

- Potentially resectable disease

- Resectable disease

- Stage IV disease with symptomatic back pain requiring palliation allowed at the
discretion of the principal investigator

- Measurable, evaluable, or nonmeasurable disease

- No neuroendocrine tumor of the pancreas

- No documented brain metastasis

- No clinically significant pleural or peritoneal effusions that cannot be drained

PATIENT CHARACTERISTICS:

- ECOG performance status 0-1

- Life expectancy ≥ 12 weeks

- Absolute neutrophil count ≥ 1,500/mm³

- Platelet count ≥ 100,000/mm³

- Hemoglobin ≥ 9 g/dL

- Serum bilirubin ≤ 1.5 times upper limit of normal (ULN)

- Alkaline phosphatase ≤ 3 times ULN (5 times ULN if liver has tumor involvement)

- AST and ALT ≤ 3 times ULN (5 times ULN if liver has tumor involvement)

- Creatinine clearance ≥ 45 mL/min

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception during and for 3 months after
completion of study treatment

- No active infection

- No serious systemic disorders that would preclude study treatment

- No significant cardiovascular disease in the form of abnormal electrocardiogram
coupled with clinical features of recent or recurrent cardiac disease (including
myocardial infarction, angina, or hypertension)

PRIOR CONCURRENT THERAPY:

- More than 4 weeks since prior investigational agents

- No prior chemotherapy for pancreatic cancer

- Must be able to discontinue aspirin, dexamethasone, and other nonsteroidal
anti-inflammatory agents for 2 days before, the day of, and 2 days after pemetrexed
disodium dose (5 days before for long-acting agents such as piroxicam)

- Must be able and willing to take folic acid and cyanocobalamin (vitamin B12)
supplementation