Treating non-small cell lung cancer with biological therapies

Biological therapies use substances that occur naturally in the body to destroy cancer cells. There are several different types of biological therapies. Two different types are used to treat advanced non-small cell lung cancer. These are cancer growth inhibitors and monoclonal antibodies.

Cancer growth inhibitors

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 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.

Erlotinib

Erlotinib (Tarceva®)| is an EGFR antagonist. It's sometimes used to treat people with non-small cell lung cancer whose cancer has come back after initial treatment, or has not responded to at least one course of chemotherapy.

Erlotinib is given as a tablet. Side effects are generally mild and can include diarrhoea, a rash, nausea and tiredness. Not all non-small cell lung cancers respond to erlotinib. Before having the drug your doctors will test the cancer cells for EGF receptors to see if it will be effective for you.

Gefitinib

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 the UK for people with advanced non-small cell lung cancer. However, it has not yet been approved by NICE. Guidance on the use of gefitinib is due to be published in late 2010 and until then it may not be possible to get gefitinib on the NHS.

Monoclonal antibodies

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. This may stop the cells from developing a new blood supply, which can cause the tumour to shrink, or at least to stop growing. Drugs that interfere with blood vessel growth in this way are called angiogenesis inhibitors or anti-angiogenics.

Bevacizumab is given as a drip (infusion) into a vein (intravenously). Side effects of bevacizumab include an allergic reaction, nausea, tiredness, diarrhoea and a lowered resistance to infection. Bevacizumab isn’t suitable for all types of non-small cell lung cancer. Your doctor can advise you if it’s a possible treatment for you.

In the UK bevacizumab is licensed for people with advanced non-small cell lung cancer and can be prescribed in combination with either cisplatin or carboplatin. However, it has not yet been approved by NICE, so it may not be possible to get it on the NHS.