Regorafenib and Nivolumab in Mismatch Repair (MMR) Refractory Colorectal Cancer

Inclusion Criteria: * Histologically confirmed diagnosis of colorectal adenocarcinoma * Proficient DNA mismatch repair (MMR) or stable microsatellite disease. * Participants with the presence of at least one lesion with measurable disease as defined by 10mm in longest diameter for a soft tissue lesions or 15mm in short axis for a lymph node by RECIST 1.1 for response assessment. * Participants must have received and progressed through or become intolerant to fluoropyrimidine, irinotecan, oxaliplatin, and bevacizumab, and if K-ras wild type, cetuximab or panitumumab containing therapies. Exceptions may apply. * Eastern Cooperative Oncology Group (ECOG) Performance Score 0 or 1 * Estimated life expectancy over 3 months. * Adequate bone marrow, liver and renal function. * Participants must not have had chemotherapy, major surgery, monoclonal antibody therapy or experimental therapy within the 21 days prior to the start of regorafenib and nivolumab administration * Women of childbearing potential must have a negative serum or urine pregnancy test (minimum sensitivity 25 IU/L or equivalent units of HCG) performed within 24 hours prior to the start of study drug and then every 4 weeks. Post-menopausal women (defined as no menses for at least 1 year) and surgically sterilized women are not required to undergo a pregnancy test. * Participants (men and women) of childbearing potential must agree to use adequate contraception beginning at the signing of the Informed Consent Form (ICF)…