Patients receive bevacizumab IV over 30-90 minutes, irinotecan hydrochloride IV over 90 minutes, leucovorin calcium IV over 2 hours, and fluorouracil IV over 46 hours on day 1. Patients also receive filgrastim (G-CSF) subcutaneously on days 5-11. Treatment repeats every 2 weeks in the absence of disease progression or unacceptable toxicity.