Inclusion Criteria:

          1. Adult males and female subjects aged 18-80 years at screening visit

          2. Pathologically confirmed diagnosis of colorectal adenocarcinoma

          3. Presenting with metastatic disease:

               -  Primary can be intact or previously resected

               -  Preferably with metastasis to the liver or other location for safe percutaneous
                  biopsy

          4. Previous treatment failure of two previous lines of active systemic chemotherapy:

               -  Previous chemotherapy must have included an oxaliplatin-containing (e.g. FOLFOX)
                  and an irinotecan-containing (e.g. FOLFIRI) regimen

               -  With or without bevacizumab

               -  Administered in adjuvant setting or for treatment of metastatic disease

               -  If KRAS wild type, must have at least one prior anti-EGFR therapy

               -  Treatment failure can be due to disease progression or toxicity

               -  Disease progression on second line therapy must be documented radiologically and
                  must have occurred during or within 30 days following the last administration of
                  treatment for metastatic disease

          5. ECOG performance score: 0-1

          6. Adequate hematological function:

               -  Absolute granulocyte count ≥ 1,200/mm3

               -  Platelet count ≥ 100,000/mm3

               -  PT/INR ≤ 1.5 or correctable to <1.5 at time of interventional procedures

               -  Hemoglobin ≥ 9 g/dL (may be corrected by transfusion)

          7. Adequate Organ Function:

               -  Creatinine ≤ 1.5 mg/dL

               -  Total bilirubin ≤ 1.5 times upper limit of normal (ULN)

               -  Alkaline phosphatase ≤ 2.5 times ULN *

               -  Aspartate aminotransferase (AST) or (SGOT) ≤ 2.5 times ULN *

               -  Alanine aminotransferase (ALT) or (SGPT) ≤ 2.5 times ULN * *or ≤5x ULN if liver
                  involvement

          8. EKG without clinically relevant abnormalities

          9. Female subjects: Not pregnant or lactating

         10. Patients with child bearing potential must agree to use adequate contraception

         11. Study specific informed consent in the native language of the subject.

        Exclusion Criteria:

          1. high frequency microsatellite instability (MSI-H)

          2. Bowel obstruction or high risk for obstruction if tumors become inflamed

          3. Moderate or severe ascites requiring medical intervention

          4. Clinical evidence or radiological evidence of brain metastasis or leptomeningeal
             involvement

          5. Peritoneal carcinomatosis

          6. Symptomatic asthma or COPD

          7. Pulmonary lymphangitis or symptomatic pleural effusion (grade ≥ 2) that results in
             pulmonary dysfunction requiring active treatment; or, oxygen saturation <92% on room
             air

          8. Bevacizumab (Avastin®) treatment within 6 weeks of baseline scheduled biopsy procedure

          9. Any of the following mood disorders: active major depressive episode, history of
             suicidal attempt or ideation

         10. Prior allogeneic bone marrow/stem cell or solid organ transplant

         11. Chronic use (> 2 weeks) of greater than physiologic doses of a corticosteroid agent
             (dose equivalent to > 5 mg/day of prednisone) within 30 days of the first day of study
             drug treatment

               -  Topical corticosteroids are permitted

         12. Prior diagnosis of an active autoimmune disease (e.g., rheumatoid arthritis, multiple
             sclerosis, autoimmune thyroid disease, uveitis).

               -  Well controlled Type I diabetes allowed

         13. Prior experimental therapy

         14. History of blood transfusion reactions

         15. Progressive viral or bacterial infection

               -  All infections must be resolved and the subject must remain afebrile for seven
                  days without antibiotics prior to being placed on study

         16. Cardiac disease of symptomatic nature

         17. History of HIV positivity or AIDS

         18. Concurrent medication known to interfere with platelet function or coagulation (e.g.,
             aspirin, ibuprofen, clopidogrel, or warfarin) unless such medications can be
             discontinued for an appropriate time period based on the drug half-life and known
             activity (e.g., aspirin for 7 days) prior to biopsy procedures

         19. History of severe hypersensitivity to monoclonal antibody drugs

         20. Psychiatric or addictive disorders or other condition that, in the opinion of the
             investigator, would preclude study participation.

         21. Subjects that lack ability to provide consent for themselves.