Gemcitabine, Capecitabine, and Erlotinib in Treating Patients With Advanced Pancreatic Cancer

DISEASE CHARACTERISTICS: * Histologically or cytologically confirmed adenocarcinoma of the pancreas * Advanced disease * No standard curative therapy available * Must have received prior first-line chemotherapy * No brain metastasis PATIENT CHARACTERISTICS: * WHO performance status 0-2 * Life expectancy ≥ 8 weeks * ANC ≥ 1.5 x 10\^9/ L * Platelet count ≥ 130 x 10\^9/ L * Hemoglobin ≥ 10 g/dL * Liver transaminases ≤ 1.5 times upper limit of normal (ULN) (≤ 5 times ULN in the presence of liver metastases) * Bilirubin ≤ 1.5 times ULN * Creatinine ≤ 130 mmol/L OR creatinine clearance \> 30 mL/min * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception * No intolerance or hypersensitivity to any of the drugs being tested * No history of interstitial lung disease * No history of severe cardiac disease * No serious uncontrolled infection * No rare hereditary disorders, i.e., galactosemia, lactase deficiency, or malabsorption of glucose or galactose syndrome * Must not be deprived of liberty or under guardianship * Must not be on probation PRIOR CONCURRENT THERAPY: * See Disease Characteristics * No prior erlotinib hydrochloride * No concurrent potent inducers or inhibitors of cytochrome P450 or CYP3A4 * More than 14 days since participation in another clinical trial