Targeted therapies for non-small cell lung cancer
Targeted therapies use substances that target the differences in the biology between cancer cells and normal cells.
There are several different types of targeted therapy. Two different types are used to treat advanced non-small cell lung cancer. These are cancer growth inhibitors and monoclonal antibodies.
Cancer growth inhibitors
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There are structures on the surface of many types of cancer cells, known as epidermal growth factor receptors (EGFRs). The receptors allow epidermal growth factor (EGF), a particular protein present in the body, to attach to them. When EGF attaches to the receptor, it becomes activated and causes chemical processes to occur inside the cell that make it grow and divide more quickly.
Drugs known as EGFR antagonists attach themselves to the EGF receptor on the cell, and prevent the receptor from being activated. This can help to stop the cancer cells from growing so quickly. There are two commonly used EGFR inhibitors - erlotinib and gefitinib. Before having the drug, your doctors will test the cancer cells taken from your lung biopsy for EGFR mutations to see if you’re likely to benefit from an EGFR antagonist.
The National Institute for Health and Clinical Excellence (NICE) is an independent body that was set up by the government. NICE assesses medicines and treatments and gives guidance to doctors on how they should be used in the NHS in England and Wales. The equivalent body in Scotland is the Scottish Medicines Consortium (SMC).
Erlotinib (Tarceva®) is an EGFR antagonist. NICE and SMC currently recommend that it can be offered to you as an initial treatment, if you’re diagnosed with a locally advanced or metastatic non-small lung cancer that tests have shown to be EGFR-positive.
NICE also recommends that erlotinib can be used as an alternative to docetaxel chemotherapy, in people with non-small cell lung cancer who have already had one chemotherapy course that hasn’t worked. It can only be used if the drug company supplies it at the same cost as docetaxel.
Erlotinib is given as a tablet. Side effects are generally mild and can include diarrhoea, a rash, nausea and tiredness.
A second growth inhibitor called gefitinib (Iressa®) works in a similar way to erlotinib. When epidermal growth factor (EGF) attaches to the receptors found on the surface of the cancer cells, an enzyme called tyrosine kinase (TK) triggers chemical processes inside the cell to make it grow and divide.
Gefitinib attaches itself to the EGF receptor on the cell and prevents the receptor from being activated. This stops the cancer cells from dividing.
Gefitinib is a type of growth inhibitor called a tyrosine kinase inhibitor (TKI). It’s given as a tablet. Side effects are generally mild and include diarrhoea, nausea, tiredness and a skin rash. Not all non-small cell lung cancers respond to gefitinib, so your doctors will test the cancer cells to see if it can be used.
Gefitinib is licensed and can be prescribed in England and Wales for people with advanced non-small cell lung cancer who test positive for the EGF tyrosine kinase mutation. It can only be used if the drug company supplies it at the fixed cost agreed under the patient access scheme.
Gefitinib is not recommended for use in the NHS in Scotland.
Monoclonal antibodies can destroy some types of cancer cells while causing little harm to normal cells. They do this by recognising certain proteins that are found on the surface of some types of cancer cells (known as receptors) and ‘locking’ onto them.
The monoclonal antibody bevacizumab (Avastin®) can attach to receptors on some lung cancer cells and stop them connecting with a different protein that helps the cell to grow.
Bevacizumab is licensed in the UK to treat advanced non-small cell lung cancer, but NICE and the SMC have not recommended it as a treatment on the NHS, so it will not be widely available.