Gemcitabine Alone or in Combination With Other Chemotherapy Drugs in Treating Patients With Metastatic Cancer of the Pancreas

DISEASE CHARACTERISTICS:

* Histologically confirmed adenocarcinoma of the pancreas
* Metastatic disease by CT scan

PATIENT CHARACTERISTICS:

Age:

* 18 and over

Performance status:

* CTC 0-2

Life expectancy:

* Not specified

Hematopoietic:

* Absolute neutrophil count at least 1,500/mm\^3
* Platelet count at least 100,000/mm\^3

Hepatic:

* Bilirubin no greater than 1.5 mg/dL
* SGOT no greater than 2.5 times upper limit of normal (ULN)
* Alkaline phosphatase less than 2.5 times ULN if SGOT greater than 1.5 times ULN
* Alkaline phosphatase any value if SGOT less than 1.5 times ULN

Renal:

* Creatinine no greater than 1.5 mg/dL

Other:

* Not pregnant or nursing
* Negative pregnancy test
* Fertile patients must use effective contraception during and for 3 months after study
* No other currently active malignancy (completed therapy and considered to be at less than 30% risk of relapse) except non-melanoma skin cancer

PRIOR CONCURRENT THERAPY:

Chemotherapy:

* No prior chemotherapy except fluorouracil (5-FU)
* At least 2 weeks since prior 5-FU
* No other concurrent chemotherapy

Endocrine therapy:

* No concurrent hormonal therapy except steroids for adrenal failure, hormonal therapy for non-disease related conditions (e.g., insulin for diabetes), or intermittent use of dexamethasone as an antiemetic

Radiotherapy:

* At least 2 weeks since prior radiotherapy
* No concurrent palliative radiotherapy except whole-brain irradiation for CNS disease