This clinical trial is focused on studying the treatment of microsatellite stable metastatic colorectal cancer, a type of colon cancer that has spread to other parts of the body and does not have changes in certain DNA sequences. The study involves a combination of treatments, including chemotherapy and immunotherapy. The chemotherapy regimen includes XELOX, which is a combination of two drugs: capecitabine and oxaliplatin. Additionally, the study uses bevacizumab, a medication that helps prevent the growth of blood vessels that feed tumors. The immunotherapy component involves pembrolizumab, also known by its code name MK-3475, which helps the immune system recognize and attack cancer cells.

The purpose of this study is to evaluate how effective this combination of treatments is as a first-line therapy for patients with this specific type of colorectal cancer that shows a high level of immune cells within the tumor. The study will monitor patients over a period of time to see how many remain alive and without disease progression after 10 months. This is a non-randomized, multicenter study, meaning that all participants will receive the same treatment, and the study is conducted at multiple locations.

Participants in the study will receive the treatments through intravenous infusions, which means the medications are delivered directly into the bloodstream through a vein. The study will last for up to 24 months, during which time the patients’ health and response to the treatment will be closely monitored. The study aims to provide valuable insights into the effectiveness of combining chemotherapy and immunotherapy for treating this type of cancer.