LMB-9 Immunotoxin in Treating Patients With Advanced Pancreatic, Esophageal, Stomach, Colon, or Rectal Cancer

RATIONALE: LMB-9 immunotoxin can locate tumor cells and kill them without harming normal cells. This may be an effective treatment for advanced pancreatic, esophageal, stomach, colon or rectal cancer. PURPOSE: Phase I trial to study the effectiveness of LMB-9 immunotoxin in treating patients who have advanced pancreatic, esophageal, stomach, colon, or rectal cancer.