Tucatinib with trastuzumab and mFOLFOX6 for treating HER2-positive metastatic colorectal cancer

The combination of tucatinib with trastuzumab and mFOLFOX6 is in development for the treatment of Human Epidermal Growth Factor Receptor 2 positive (HER2+) rat sarcoma viral oncogene homolog wild type (RAS WT) metastatic colorectal cancer. RAS WT refers to a group of genes which control cell growth, which have not mutated. Colorectal cancer starts in the large bowel (colon) and the back passage (rectum). Metastatic cancer is when the cancer has spread from where it started to elsewhere in the body. HER2 is a protein which promotes the growth of colorectal cancer cells and is found more frequently in RAS WT tumours. Risk factors for colorectal cancer can include obesity, smoking and alcohol consumption, with symptoms including blood in the stool, weight loss and anaemia. Patients with HER2+ RAS WT colorectal cancer do not respond as well to current standard of care treatments as patients with HER2 negative tumours. Therefore, there is a need for more effective treatments for this patient group.