Inclusion Criteria:

- Voluntary consent form

- Diagnosis of GI malignancy with a GCC protein expressing tumor

- Male or female patients 18 years or older with measurable disease as defined by
RECIST

- Female patients who are post menopausal, surgically sterile, or agree to practice 2
effective methods of contraception or agree to abstain from heterosexual intercourse

- Male patients who agree to practice effective barrier contraception or agree to
abstain from heterosexual intercourse

- Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1

- Adequate bone marrow, hepatic and renal function as specified in the protocol

Exclusion Criteria:

- Female patients who are lactating or have a positive serum pregnancy test during the
screening period

- Any serious medical or psychiatric illness that could interfere with the completion
of treatment

- Major surgery or treatment with investigational drug before the first dose

- Serious infection within 14 days before the first dose of study drug

- Known HIV, inflammatory bowel disease, viral hepatitis or cerebral/meningeal brain
metastases

- Patients with cardiovascular conditions specified in protocols

- Patients with history of another primary malignancy not in remission for at least 3
years

Please note that there are additional inclusion and exclusion criteria. The study center
will determine if you meet all of the criteria.

Site personnel will explain the trial in detail and answer any question you may have if
you do qualify for the study. You can then decide whether or not you wish to participate.
If you do not qualify for the trial, site personnel will explain the reasons.