OUTLINE: This is a randomized, double blind, placebo controlled, crossover study. Patients are randomized to one of two treatment arms: Arm I: Patients receive fluorouracil IV continuously on days 1-21 and IM-862 intranasally three times daily on days 1-28. Courses repeat every 4 weeks in the absence of disease progression. Patients who develop disease progression are taken off fluorouracil and IM-862, and then receive irinotecan IV over 90 minutes weekly for 4 weeks. Courses repeat every 6 weeks in the absence of disease progression. Arm II: Patients receive fluorouracil as in arm I and placebo intranasally three times daily on days 1-28. Courses repeat every 4 weeks in the absence of disease progression. Patients who develop disease progression are taken off fluorouracil and placebo, and then receive irinotecan and IM-862 as in arm I on days 1-42. Courses repeat every 6 weeks in the absence of disease progression. Quality of life is assessed prior to study, and then prior to every course during study. Patients are followed for a minimum of 6 months.