DISEASE CHARACTERISTICS: Histologically or cytologically proven gallbladder or bile duct carcinoma with metastatic or recurrent disease deemed unresectable and not considered a candidate for potentially curative therapy Measurable or evaluable disease No known active CNS disease Closed to bile duct carcinoma as of July 1999

PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Life expectancy: At least 12 weeks Hematopoietic: Absolute neutrophil count at least 1500/mm3 Platelet count at least 100,000/mm3 Hepatic: SGOT no greater than 5 times upper limit of normal (ULN) Bilirubin no greater than 1.5 mg/dL OR Bilirubin no greater than 2 times ULN in patients with biliary stents or percutaneous biliary catheters Renal: Creatinine no greater than 1.5 mg/dL Cardiovascular: No New York Heart Association class III or IV heart disease Other: Nutritional intake at least 1200 kcal/day No uncontrolled infection or chronic debilitating disease Not pregnant or nursing Fertile patients must use effective contraception No uncontrolled seizure disorder No prior malignancy within 5 years except adequately treated basal cell/squamous cell carcinomas and adequately treated noninvasive carcinomas

PRIOR CONCURRENT THERAPY: Biologic therapy: No prior biological therapy or immunotherapy for recurrent or metastatic disease No concurrent biologic therapy Chemotherapy: No prior chemotherapy for recurrent or metastatic disease Prior adjuvant chemotherapy allowed if used as a radiation sensitizer for completely resected disease No other concurrent chemotherapy Endocrine therapy: Not specified Radiotherapy: No prior radiotherapy for recurrent or metastatic disease Prior adjuvant radiotherapy allowed if used as a radiation sensitizer for completely resected disease No radiotherapy to greater than 25% of bone marrow No radiotherapy within the past 4 weeks No concurrent radiotherapy Concurrent CNS radiation allowed Surgery: No post abdominal exploration (with or without resection) within the past 4 weeks Other: No concurrent medication for other medical conditions except for: Analgesics Chronic treatments for preexisting conditions Agents required for life-threatening medical conditions No laxatives