For course 1, and then course 3 and beyond, patients receive oxaliplatin IV over 2 hours on day 1, followed by gemcitabine IV over 30 minutes on days 1 and 8, and then fluorouracil IV continuously on days 1-14. For course 2, patients receive treatment in the same manner as in course 1, except gemcitabine is given initially, followed by oxaliplatin, and then fluorouracil. Treatment continues every 21 days in the absence of unacceptable toxicity or disease progression.