Pembrolizumab, Capecitabine, and Bevacizumab in Treating Patients With Microsatellite Stable Colorectal Cancer That Is Locally Advanced, Metastatic, or Cannot Be Removed by Surgery

This phase II trial studies the side effects and best dose of capecitabine when given together with pembrolizumab and bevacizumab, and investigates how well they work in treating patients with microsatellite stable colorectal cancer that has spread to nearby tissues or lymph nodes, has spread to other places in the body, or that cannot be removed by surgery. Monoclonal antibodies, such as pembrolizumab and bevacizumab, may interfere with the ability of tumor cells to grow and spread. Drugs used in chemotherapy, such as capecitabine, work in different ways to stop the growth of tumor cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. Giving capecitabine together with pembrolizumab and bevacizumab may work better in treating patients with colorectal cancer.