A Phase II Trial Assessing Nivolumab in Class II Expressing Microsatellite Stable Colorectal Cancer

Inclusion Criteria: * Histologically confirmed locally advanced or metastatic MSS CRC with class II expression (greater than 1% cancer cell positivity for class II expression on immunohistochemistry). * Eastern Cooperative Oncology Group (ECOG) performance status 0-2 (APPENDIX 1) * Age ≥ 18 years * Patients must have completed all standard of care therapy that the treating oncologist deems appropriate. Trial treatment as first line therapy is permitted if the patient has declined standard of care therapy. * CT scan of chest, abdomen, pelvis within 28 days of registration demonstrating unidimensionally measurable disease as per RECIST version 1.1 (APPENDIX 3). * Demonstrate adequate haematological function: * Platelet count ≥100 x 109 /L * Neutrophils ≥1.5 x 109/L * Haemoglobin ≥ 90 g/L * Demonstrate adequate hepatic function: * Serum bilirubin ≤1.5 x upper limit of normal (ULN) * Serum AST or ALT ≤2.5 x ULN or \<5 x ULN in the presence of liver metastases * Demonstrate adequate renal function o Creatinine clearance \<1.5 times ULN and \>30ml/min (as per institutional standard). * Provision of signed and dated, written informed consent prior to any trial specific procedures, sampling and analyses. * Negative pregnancy test (female patients of reproductive potential). (Serum Test must be negative) * Patients must agree to the use of contraception as detailed in section 7.8 Exclusion Criteria: * Previous treatment with PD1/PDL1 inhibitors. * Untreated sympto…