Inclusion Criteria:

- Patients must have histologically-proven, metastatic gastrointestinal, kidney, or
lung cancer who have had disease progression on at least two prior systemic
therapies.

- ECOG performance status of 0, 1, or 2 and estimated survival of at least 3 months.

- Patients must be felt to have recovered from effects of prior therapy, such as past
expected WBC nadir for chemotherapy (> 2 weeks for most agents, > 6 weeks for
nitrosoureas or mitomycin-C)

- Patient consent must be obtained prior to entrance onto study.

- White blood count > 3500/mm3; platelet count of at least 100,000/mm3; hemoglobin >
9.0 gm/dl; bilirubin, AST, ALT less than 3 times the upper limit of normal; serum
creatinine < 1.8.

- Corticosteroids and immunosuppressive agents are not permitted during the course of
the study. Patients must have received no corticosteroids or immunosuppressive
medications at least 2 weeks prior to entrance on-study.

- Patients with elevated temperatures > 100.5 degrees F, must have sources of occult
infection excluded.

- Women of childbearing potential must have a negative pregnancy test and must take
adequate precautions to prevent pregnancy during treatment.

Exclusion Criteria:

- Evidence of significant cardiovascular disease including history of recent (< 6
months) myocardial infarction, uncompensated congestive heart failure, primary
cardiac arrhythmias (not due to electrolyte disorder or drug toxicity, for example)
beyond occasional PVC's, angina, or cerebrovascular accident.

- Prior history of psychiatric disorder that could be exacerbated by interferon therapy
or which could preclude completion of this therapy.

- Pregnancy or lactation.

- History of hypersensitivity to interferon alfa or fluoropyrimidines.

- History of severe debilitating pulmonary disease, such as chronic obstructive
pulmonary disease requiring continuous oxygen therapy.

- History of autoimmune disease requiring immunosuppression.

- Documented inflammatory joint or systemic inflammatory disease (such as Lupus) which
could be exacerbated by interferon therapy.