Evaluate the Efficacy of MEDI4736 in Immunological Subsets of Advanced Colorectal Cancer

Inclusion Criteria

• Written informed consent obtained.
• Histologically- or cytologically- confirmed CRC.
• Microsatelite-high colorectal cancer (also known as MSI-H, DNA mismatch repair deficient, or sometimes Lynch syndrome); or increased Tumor-Infiltrating Lymphocytes in an archived tumor specimen or fresh biopsy.
• Locally advanced or metastatic CRC
• Subjects have received two or more standard available therapies known to prolong survival and for which they would be considered eligible. At a minimum, such therapies should include regimens containing oxaliplatin and irinotecan in combination with a fluoropyrimidine (e.g., FOLFOX and FOLFIRI or their variants).
• Age ≥ 18 years at time of study entry.
• Eastern Cooperative Oncology Group (ECOG) status of 0 or 1
• Adequate organ and marrow function as defined below:
• Absolute neutrophil count ≥ 1,500/mm3.
• Platelet count ≥ 90,000/mm3.
• AST and ALT ≤ 3 × institutional upper limit of normal (ULN) or ≤ 5 × ULN for subjects with liver metastases.
• Bilirubin ≤ 1.5 × ULN or ≤ 3 × ULN for subjects with documented/suspected Gilbert's disease.
• Serum creatinine ≤ 1.5 x ULN;
• Radiographically measurable disease per RECIST 1.1.
• Life expectancy ≥ 16 weeks.
• Willingness to provide consent for use of archived tissue for research purposes.
• Subjects will be required to agree to a biopsy performed at baseline and again at week 8 of the study in order to be eligible for enrollment in stage 1 of the study
• Females of childbearing potential who are sexually active with a nonsterilized male partner must use 2 methods of effective contraception from screening, and must agree to continue using such precautions for 90 days after the final dose of investigational product; cessation of birth control after this point should be discussed with a responsible physician. Periodic abstinence, the rhythm method, and the withdrawal method are not acceptable methods of birth control.
• Females of childbearing potential are defined as those who are not surgically sterile (ie, bilateral tubal ligation, bilateral oophorectomy, or complete hysterectomy) or postmenopausal (defined as 12 months with no menses without an alternative medical cause).
• Subjects must use 2 acceptable methods of effective contraception as described in below.
• Nonsterilized males who are sexually active with a female partner of childbearing potential must use 2 acceptable methods of effective contraception from Day 1 and for 90 days after receipt of the final dose of investigational product.

Exclusion Criteria

• Anticancer therapy, monoclonal antibody or major surgery within 4 weeks prior to the first dose of MEDI4736.
• Concurrent use of hormones for non-cancer-related conditions (e.g., insulin for diabetes and hormone replacement therapy) is acceptable.
• Any prior Grade ≥ 3 irAE while receiving immunotherapy (including anti-CTLA-4 or anti-CD137 MAb) or any unresolved irAE of any grade (controlled irAE endocrinopathies are allowed).
• Prior exposure to any anti-PD-1 or anti-PD-L1 antibody.
• Current or prior use of immunosuppressive medication within 28 days before the first dose of MEDI4736, with the exceptions of intranasal and inhaled corticosteroids or systemic corticosteroids at physiological doses, which are not to exceed 10 mg/day of prednisone, or an equivalent corticosteroid.
• Any unresolved toxicity CTCAE >Grade 2 from previous anti-cancer therapy.
• Active autoimmune disease within the past 2 years, except for mild conditions not requiring systemic treatment, such as vitiligo.
• Any concurrent chemotherapy, immunotherapy, biologic or hormonal therapy for cancer treatment. NOTE: Local treatment of isolated lesions, excluding target lesions, for palliative intent is acceptable (e.g., by local ablation, surgery or radiotherapy).
• Active or prior documented inflammatory bowel disease (e.g., Crohn's disease, irritable bowel syndrome, ulcerative colitis).
• Receipt of radiation therapy within 4 weeks prior to s