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

DISEASE CHARACTERISTICS: Histologically or cytologically confirmed advanced adenocarcinoma of the colon, rectum, pancreas, esophagus, or stomach that is refractory to standard treatment Overexpression of the Lewis-Y antigen Measurable or evaluable disease No CNS metastasis Metastatic liver disease from primary tumor allowed PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-1 Life expectancy: At least 3 months Hematopoietic: Platelet count greater than 100,000/mm^3 Absolute granulocyte count greater than 1,200/mm^3 Hepatic: Bilirubin normal SGOT and SGPT no greater than 1.5 times upper limit of normal Hepatitis B or C antigen negative No liver disease (e.g., alcohol liver disease) Albumin at least 3.0 g/dL Renal: Creatinine no greater than 1.4 mg/dL Creatinine clearance at least 60 mL/min Proteinuria no greater than 1 g/24 hours (grade II toxicity-like) Cardiovascular: No prior coronary artery disease No New York Heart Association class II, III, or IV congestive heart failure No arrhythmia requiring treatment Pulmonary: FEV_1 and FVC greater than 65% predicted Other: No other concurrent malignancy No active peptic ulcer disease No known allergy to omeprazole No known seizure disorder No concurrent medical or psychiatric condition that would preclude study participation No contraindication to pressor therapy Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: At least 3 weeks since prior chemotherapy (6 weeks for nitrosoureas or mitomycin) and recovered Endocrine therapy: At least 3 weeks since prior hormonal therapy Radiotherapy: At least 3 weeks since prior radiotherapy and recovered Surgery: Not specified