DISEASE CHARACTERISTICS: Histologically confirmed ductal or undifferentiated primary pancreatic cancer for which no standard curative therapy exists Progressive locally advanced disease after combined chemotherapy and radiotherapy OR Not a candidate for combined therapy OR Metastatic disease No islet cell, acinar cell, or cystadenocarcinomas Measurable or evaluable disease No known brain metastases

PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Karnofsky 50-100% Life expectancy: Not specified Hematopoietic: WBC at least 3,500/mm3 Absolute neutrophil count at least 1,500/mm3 Platelet count at least 100,000/mm3 Hepatic: Bilirubin no greater than upper limit of normal (ULN) SGOT no greater than 2.5 times ULN Renal: Creatinine no greater than ULN OR Creatinine clearance at least 60 mL/min Cardiovascular: No symptomatic congestive heart failure No unstable angina No cardiac arrhythmia Other: No other uncontrolled illness No active infection No allergy to platinum compounds, gemcitabine, or antiemetics No other malignancy within the past 5 years except basal cell skin cancer or carcinoma in situ of the cervix No evidence of neuropathy except preexisting grade I or II Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY: Biologic therapy: At least 4 weeks since prior biologic therapy or immunotherapy No concurrent immunotherapy Chemotherapy: No prior chemotherapy for metastatic disease At least 6 months since prior adjuvant chemotherapy, including cisplatin or gemcitabine, for radiosensitization in locally advanced disease No prior cisplatin or gemcitabine for locally advanced disease No other concurrent chemotherapy Endocrine therapy: Not specified Radiotherapy: No prior radiotherapy to 25% or more of bone marrow No concurrent radiotherapy Surgery: Not specified Other: No other concurrent investigational agents