Antibody therapy: A new drug offering hope to patients with advanced bowel cancer has just been launched in the Republic. Dr Muiris Houston, Medical Correspondent, reports.
Cetuximab is an innovative antibody therapy licensed for the treatment of colon cancer where the cancer has already spread to other sites in the body (metastatic cancer). According to research published in the New England Journal of Medicine (NEJM), where cetuximab is used in combination with a chemotherapy drug, irinotecan, half of all patients treated had the progression of their cancer slowed by more than four months.
The Bond study, which was carried out in several European centres, found that the new combination therapy shrank tumour size by half or more in about a quarter of the people treated. However, the three-year study of 329 patients did not find sufficient evidence to prove that cetuximab improved patients' survival.
Commenting on the results, Dr David Fennelly, consultant medical oncologist at St Vincent's Hospital, Dublin, said: "The Bond study results show cetuximab to be effective in patients whose tumours have become resistant to conventional therapy. The challenge in metastatic colorectal cancer is to provide new hope for patients with the disease."
Finding effective treatments for advanced colon cancer may also increase the options available to patients with earlier stages of the disease, he added.
Dr Charles Erlichman, chairman of the department of oncology at the Mayo Clinic, writing in the NEJM, described the study as "the first step in defining the role of antibody targeted therapy in patients with colorectal cancer."
Cetuximab belongs to a new class of cancer drugs called targeted therapies - drugs designed to attack the source of the cancer and leave healthy cells alone. It targets a receptor on the outside of the bowel cancer cell called the epidermal growth factor receptor (EGFR), which promotes tumour growth and development. Cetuximab disables EGFR, preventing growth of the cancer and making it susceptible to the killing effects of chemotherapy drugs such as irinotecan.
When bowel cancer reaches an advanced stage, it sets up secondary growths in the liver and other parts of the body. Some 30 per cent of patients diagnosed with bowel cancer present with advanced disease. Cancer of the colon and rectum is the second commonest cancer in the Republic. There are 1,800 new cases of the cancer here each year, with some 900 deaths from the disease annually.