Colorectal or bowel cancer is a cancer that begins in the large bowel and is the fourth most common cancer in the UK. Metastatic/advanced colorectal cancer, or Stage IV, occurs when the cancer has spread to another part of the body; this is most commonly to the liver. A small proportion of colorectal cancer cases develop due to deficiencies in a repair mechanism for DNA; this may contribute to an increase in potential faulty (mutated) DNA. A high rate of this mutation is known as high microsatellite instability or mismatch repair deficient. These subsets of patients may have outcomes which are worse than those observed in the overall metastatic colorectal cancer population.
The most common treatment options for advanced colorectal cancer in the UK is surgery, radiotherapy and chemotherapy. Pembrolizumab is a type of immunotherapy that is delivered intravenously by a drip and that works by targeting specific proteins that stimulate an immune response attacking the cancer cells. It increases the body’s natural ability to identify and kill cancer cells. If licenced, pembrolizumab will offer an additional first line treatment option for patients with advanced colorectal cancer and prolong the time without cancer progression and overall survival.
Nivolumab works by improving the activity of white blood cells thereby increasing the ability of the immune system to kill cancer cells. Cabozantinib works to stop signals that cancer cells use to divide and grow. It is thought that when used in combination, both drugs may be more effective than each drug on its own. If licenced, nivolumab in combination with cabozantinib may improve long-term outcomes in mRCC patients who currently have limited treatment options.