Nivolumab is a medication used in this trial to treat metastatic colorectal cancer. It works by helping the immune system recognize and attack cancer cells more effectively. Nivolumab is often used in cancers that have specific genetic features, such as microsatellite instability high (MSI-H) or mismatch repair deficient (dMMR).

Ipilimumab is another medication used in combination with Nivolumab in this trial. It also helps the immune system fight cancer by targeting a different part of the immune response. When used together with Nivolumab, it may enhance the overall effectiveness of the treatment against cancer cells.

Investigator’s Choice Chemotherapy refers to a standard chemotherapy treatment selected by the trial investigator. This treatment is used as a comparison to evaluate the effectiveness of Nivolumab alone or in combination with Ipilimumab. Chemotherapy works by using drugs to kill or slow the growth of cancer cells.

Microsatellite Instability High (MSI-H) or Mismatch Repair Deficient Metastatic Colorectal Cancer (dMMR) – This type of colorectal cancer is characterized by genetic mutations that affect the DNA repair process, leading to high levels of microsatellite instability. It often begins in the colon or rectum and can spread to other parts of the body. The disease progresses as cancer cells grow uncontrollably, forming tumors that can invade nearby tissues and organs. Patients with this condition may experience symptoms such as changes in bowel habits, abdominal pain, and weight loss. The progression of the disease can vary, with some tumors growing slowly while others may advance more rapidly. Understanding the genetic basis of this cancer is crucial for developing targeted therapies.