Inclusion Criteria:

• Have histologically confirmed colorectal cancer that is metastatic with measurable disease.
• For the Phase I portion: Have recurred or progressed after at least one FOLFOX +/- bevacizumab regimen but no more than three prior chemotherapy or biologic regimens for metastatic colorectal cancer.
• For the Phase II portion: Have recurred or progressed within 6 months of the last cycle of FOLFOX +/- bevacizumab first-line regimen for metastatic colorectal cancer.
• At least 4 weeks have elapsed since the last chemotherapy, radiotherapy, immunotherapy, or biologic therapy prior to enrollment (except at least 6 weeks in the case of nitrosourea and mitomycin).
• Have not received any other investigational agents within 4 weeks of study entry and have fully recovered from any adverse event due to prior therapy.
• At least 4 weeks have elapsed since any major surgery.
• Have ECOG performance status of 0, 1, or 2.
• Have adequate bone marrow and organ function

Exclusion Criteria:

• Have an active, uncontrolled infection.
• Have known HIV positive status.
• Have known or suspected cerebral metastasis.
• Have had a myocardial infarction (MI) or cerebrovascular accident (CVA) within the last 6 months; or meet the criteria for AHA class III or IV congestive heart failure (CHF).
• Have a medical condition requiring chronic use of high-dose corticosteroids or other chronic immunosuppressive therapy (e.g. methotrexate, azathioprine).
• Have a history of greater than or equal to Grade 2 allergic reaction or hypersensitivity following exposure to humanized or human monoclonal antibodies (but not chimeric antibodies).
• Pregnant or breastfeeding women and male or female patients who do not agree to use effective contraceptive method(s) during the study.