Inclusion Criteria

DISEASE CHARACTERISTICS: Histologically proven malignant solid tumor that has failed prior
conventional chemotherapy or for which no established therapy exists Recurrent or
metastatic gastrointestinal adenocarcinoma with no prior therapy eligible No evidence of
CNS metastases (brain or leptomeningeal disease)

PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-1 Life expectancy: At
least 12 weeks Hematopoietic: WBC at least 3,500/mm3 Neutrophil count at least 1,500/mm3
Platelet count at least 100,000/mm3 Hepatic: Bilirubin no greater than 1.8 mg/dL SGOT and
SGPT less than 3 times upper limit of normal (ULN) Alkaline phosphatase less than 3 times
ULN (5 times ULN for metastatic disease) Renal: Creatinine no greater than 1.8 mg/dL OR
Creatinine clearance at least 60 mL/min Cardiovascular: No congestive heart failure Other:
No uncontrolled diabetes Not pregnant or nursing Negative pregnancy test No other serious
medical illness (e.g. clinically active infectious process) No psychiatric illness
precluding study No ascites or pleural effusion

PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: At least 4 weeks
since prior chemotherapy and recovered No more than 1 prior adjuvant chemotherapy regimen
No more than 1 prior chemotherapy regimen for recurrent or metastatic disease No prior
irinotecan or raltitrexed At least 8 weeks since prior nitrosourea or mitomycin and
recovered Endocrine therapy: Not specified Radiotherapy: At least 4 weeks since prior
radiotherapy and recovered Prior radiotherapy limited to no greater than 25% of bone
marrow Surgery: Not specified