MGD007 Combined With MGA012 in Relapsed/Refractory Metastatic Colorectal Cancer

Inclusion Criteria: * Histologically proven, relapsed/refractory metastatic colorectal cancer * Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1 * Measurable disease per RECIST 1.1 criteria * Participants in the Dose Escalation Phase must have had recurrence, progression or intolerance to standard therapy consisting of at least 2 prior standard regimens (containing a fluoropyrimidine plus a platinum analogue and/or irinotecan) for metastatic disease. Participants in the Cohort Expansion portion will be allowed to participate after 1 prior standard regimen. Those who are inappropriate candidates for or have refused treatment with these regimens are also eligible. No more than 5 prior therapies are permitted. Patients previously treated with MGD007 on Study Protocol CP-MGD007-01 and who did not develop antibodies to MGD007 while on the CP-MGD007-01 study, may be enrolled. Patients that were previously treated on CP-MGD007-01 will only be treated on this study once MTD/MAD has been defined. * Availability of sufficient tumor specimens to enable retrospective determination of gpA33, CD3, PD-1, and PD-L1 expression * 30 participants in the Cohort Expansion portion must have lesions that are accessible for paired biopsies with acceptable clinical risk in the judgment of the investigator. Exclusion Criteria: * Symptomatic central nervous system (CNS) metastases. No concurrent treatment for the CNS disease; no progression of CNS metastases on MRI or CT for at least 14 days after last day of prior therapy for the CNS metastases; no concurrent leptomeningeal disease or cord compression * History of known or suspected autoimmune disease with certain exceptions * History of prior allogeneic bone marrow, stem-cell, or solid organ transplantation. * Major surgery, systemic anti-neoplastic therapy, or investigational therapy within 4 weeks * Radiation therapy within 2 weeks * Systemic corticosteroids (≥ 10 mg per day prednisone or equivalent) or other immune suppressive drugs within the 14 days * History of Grade 3 or greater drug-related diarrhea/colitis during treatment with checkpoint inhibitors including anti-LAG-3, anti-PD-1, anti PD-L1, or anti-CTLA-4 antibodies * Clinically significant cardiovascular disease; gastrointestinal disorders; pulmonary compromise; viral, bacterial, or systemic fungal infections * History of positive testing for human immunodeficiency virus or history of acquired immune deficiency syndrome * History of hepatitis B or hepatitis C infection or known positive test for hepatitis B surface antigen, hepatitis B core antigen, or hepatitis C polymerase chain reaction.