The primary goal of this Phase 1 study is to characterize the safety and tolerability of MGD007 and establish the maximum tolerated dose (MTD) and schedule of MGD007 administered to patients with metastatic colorectal carcinoma. Pharmacokinetics, pharmacodynamics, and the anti-tumor activity of MGD007 will also be assessed.

This is an open-label, multi-center, Phase 1 dose-escalation study to define a MTD, describe preliminarily safety, and to assess PK, immunogenicity, and potential anti-tumor activity of MGD007 in patients with relapsed or refractory metastatic colorectal cancer.

In the initial phase of the study, two dose schedules will be assessed in dose escalation, once weekly and once every three weeks administration of single agent MGD007. Following the establishment of an MTD, additional patients will enroll in four separate dose expansion cohorts to further optimize the dose and schedule of MGD007 administration.

In all segments of the study, patients who benefit from MGD007 treatment and continue to meet eligibility may continue treatment in Cycles 2 and beyond.

Inclusion Criteria:

• For the dose escalation cohorts, histologically-proven metastatic colorectal adenocarcinoma that is refractory to 2 prior standard treatment regimens or standard treatment was declined.
• For the dose expansion cohorts, histologically-proven metastatic colorectal adenocarcinoma that is refractory to 1 prior standard treatment regimen or standard therapy was declined.
• Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1
• Life expectancy of at least 12 weeks
• Measurable disease
• Intolerance to at least 2 prior standard therapy regimens
• Acceptable laboratory parameters
• Adult (≥18 years old)

Exclusion Criteria:

• Known brain metastasis
• Any prior history of or suspected current autoimmune disorders (with the exception of vitiligo, resolved childhood atopic dermatitis, prior Grave's disease)
• Prior history of allogeneic bone marrow, stem-cell, or solid organ transplantation
• Prior treatment with checkpoint inhibitors and other immunotherapy treatments, including anti-LAG-3, anti-PD-1, anti-PD-L1 or anti-CTLA-4 antibodies, if less than 5 half lives before study drug administration
• Prior history of Grade 3 or greater drug-related diarrhea/colitis during treatment with checkpoint inhibitors or other immunotherapy treatments.
• Treatment with any local or systemic anti-neoplastic therapy or any other investigational agent in the 4 weeks prior to study drug administration
• Require, at the time of study entry, treatment with steroids > 10 mg/day of oral prednisone (or equivalent), except topical use, steroid inhaler, nasal spray or ophthalmic solution
• History of clinically significant cardiovascular disease, gastrointestinal disorder, or significant pulmonary compromise.
• Second primary malignancy that has not been in remission for greater than 3 years, with the exception of non-melanoma skin cancer, cervical carcinoma in situ,or squamous intraepithelial lesion on PAP smear, localized prostate cancer (Gleason score <6), or resected melanoma in situ.