Briefing Note - cetuximab (Erbitux)

SMC accepted cetuximab for the treatment of patients with epidermal growth factor receptor (EGFR)-expressing, Kirsten rat sarcoma (KRAS) wild-type metastatic (spreading) colorectal cancer in combination with chemotherapy. Use is restricted to patients with metastases confined to the liver that are considered non-resectable but may become amenable to potentially curative liver resection after responding to chemotherapy plus cetuximab.

• Metastatic colorectal cancer is cancer of the large bowel and rectum that has spread to other parts of the body. KRAS is a gene that commonly mutates in 35-45% of people with colorectal cancer.1 The presence of the KRAS mutation helps to decide appropriate treatment as patients with tumours exhibiting the KRAS mutation do not respond to conventional treatment with epidermal growth factor inhibitors.
• Chemotherapy is given to destroy cancer cells or stop them from spreading. Cetuximab is a monoclonal antibody that prevents the binding and activation of those signalling pathways which are essential for cancer cell growth, invasion and spread. Cetuximab is given via a drip once weekly.
• Results from several studies in patients with KRAS wild-type status who had not previously received chemotherapy for metastatic disease showed an increase in overall response rate and increased progression-free survival time by approximately 0.5-1 month, when cetuximab was added to standard combination chemotherapy.
• Side effects were more commonly experienced when cetuximab was added to chemotherapy than with chemotherapy alone and included skin reactions, neutropenia (abnormally low white blood cell count) and diarrhoea.
• This SMC advice on cetuximab takes account of the benefits of a patient access scheme (PAS). A PAS is a scheme proposed by a manufacturer in order to improve the cost effectiveness of a drug and enable patients to receive access to cost-effective new medicines. The PAS proposed for cetuximab would mean the drug is available at a discounted price to NHS Scotland.
• SMC accepted cetuximab for use in NHSScotland because it has the potential to give this select group of patients a longer period of time without the disease progressing, perhaps allowing the opportunity for surgery to remove the tumour. This SMC advice is dependent upon the continuing availability of the PAS in NHS Scotland.