Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically or cytologically confirmed pancreatic adenocarcinoma or poorly
differentiated carcinoma (originating in the pancreas)

- Locally advanced or metastatic disease

- Not eligible for curative resection

- Must have measurable or evaluable disease as defined by RECIST criteria

- No CA19-9 elevation as only evidence of disease

- No known brain metastases

PATIENT CHARACTERISTICS:

- ECOG performance status 0-2

- Absolute neutrophil count ≥ 1,500/mm³

- Platelet count ≥ 125,000/mm³

- Bilirubin < 1.5 times upper limit of normal (ULN)

- AST and ALT ≤ 2.5 times ULN

- Alkaline phosphatase < 3 times ULN

- Creatinine ≤ 1.5 times ULN OR creatinine clearance ≥ 60 mL/min

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective nonhormonal contraception

- No coexisting medical condition that would preclude study compliance

- No inability to ingest tablets

- No active illness (e.g., active or uncontrolled infection, uncontrolled cardiac
disease) that would preclude study participation

- No chronic uncontrolled diarrhea and/or daily emesis

- No other cancer within the past 5 years except for surgically removed noninvasive
nonmelanoma skin cancer or in situ cervical cancer

PRIOR CONCURRENT THERAPY:

- No prior chemotherapy for metastatic disease

- No prior gemcitabine

- No prior imatinib mesylate

- Prior surgical resection and adjuvant fluorouracil chemotherapy allowed provided
there was an interval of > 6 months between the last dose of adjuvant chemotherapy
and recurrence of pancreatic cancer

- Prior fluorouracil as a radiosensitizing agent allowed

- At least 4 weeks since prior radiotherapy and recovered

- Must have evidence of disease outside the radiation fields OR radiologically
confirmed disease progression within the radiation fields after completion of
radiotherapy

- No concurrent therapeutic warfarin

- Prophylactic warfarin ≤ 1 mg daily allowed for prophylaxis of central venous
catheter thrombosis

- Low molecular weight heparin or heparin allowed for anticoagulation

- No concurrent chronic systemic corticosteroids

- No other concurrent agents or therapies, including chemotherapy, immunotherapy,
hormonal cancer therapy, radiotherapy, or cancer surgery

- No other concurrent experimental medications

- No concurrent filgrastim (G-CSF) or sargramostim (GM-CSF)