The new wave of therapies
Antibody drugs, called cetuximab and panitumumab, can inhibit cancer growth by blocking growth signals from a particular type of protein on the surface of the cancer cells.
This protein is known as the epidermal growth factors receptor.
These drugs are part of a new wave of personalised medicines that are designed to match the specific patient.
Bowel cancer is Australia’s third-most common type of newly diagnosed cancer, with about 17,000 people diagnosed in 2018. Of these, roughly 5,000 will have an advanced metastatic condition, where the cancer has spread to other parts of the body. While 90% of bowel cancers can be treated effectively in the early stages, it remains Australia’s second deadliest cancer, as it often goes undetected.
The Flinders team was involved in a clinical trial with 572 advanced bowel cancer patients to determine the effectiveness of cetuximab for those who had already received chemotherapy.
Half of these patients received this new antibody therapy, while the other half received full support without antibody therapy. Professor Karapetis and his team tested whether patients in each group lived longer, if their cancer growth slowed, and what their quality of life was like during the treatment.
The study showed that some patients on cetuximab tolerated the treatment well, lived longer, had improved symptoms and maintained their quality of life. “It demonstrated that this treatment was effective, but we saw that many patients were not benefitting,” says Professor Karapetis.
The team wanted to find a way to determine in advance who might benefit, and who might not. They had seen results from other studies suggesting that patients who had a type of bowel cancer with a mutated version of the so-called KRAS gene – part of the cancer’s epidermal growth factor receptor pathway – might not respond to the new antibody drugs.