Afatinib: Effects, Uses & Risks

The drug afatinib is a relatively new agent used in the treatment of lung cancer. It works against cancer by blocking growth factors in cells.

What is afatinib?

Lung cancer-affected alveoli (alveoli) labeled in section. Click to enlarge. The drug afatinib is used to treat adult patients suffering from advanced-stage non-small cell lung cancer. It is a relatively new active ingredient that was only approved in the European Union and the United States in 2013 in tablet form. These are taken once daily on an empty stomach and are designed to prevent altered growth factors from binding to altered receptors on the one hand and to prevent unhindered cell growth from being activated on the other. Afatinib belongs to the group of kinase inhibitors. Their curative effect is based on the fact that the active ingredients bind to enzymes that play an important role in the development and spread of a wide variety of cancers. Because kinase inhibitors are targeted against different types of cancer, such as lung cancer, breast cancer, or colorectal cancer, they are considered better tolerated than traditional cancer drugs.

Pharmacologic action

Like all other cells in the body, cancer cells are stimulated to proliferate by various growth factors. To stimulate cell growth, the growth factor binds to the cell’s receptor. This causes the receptor to change under the influence of the enzyme tyrosine kinase, whereupon the processes responsible for growth and multiplication are activated. The fact that tumor cells grow and multiply in an uncontrolled manner is due to the fact that they either have too large a number of receptors for cell growth or that they have been altered too much. The active ingredient afatinib targets this mechanism: It deposits itself directly at the sites where growth factors are formed, thereby permanently and specifically blocking them. The drug makes no distinction between natural and modified receptors. This prevents a cancer-promoting signal from being delivered to the cells of the organism. At the molecular level, afatinib impairs the function of protein and lipid kinases. Cancer cells can not only be hindered in their growth by the drug, but also destroyed. Thus, the drug is also similar to other kinase inhibitors in terms of its mode of action. The effect of the drug lasts for a comparatively long time, 37 hours.

Medical application and use

Afatinib is prescribed exclusively for adult patients suffering from locally advanced bronchial carcinoma. The drug is also effective if the cancer has already spread to other organs with metastases. A prerequisite for treatment with afatinib, however, is that the patient has activating EGFR mutations. A corresponding test is a prerequisite before the active substance is administered for the first time. Afatinib can treat about 80 percent of all lung cancer patients, as this percentage suffers from non-small cell lung cancer. Like small cell lung cancer, which is considered to be particularly aggressive, this form of lung cancer is asymptomatic for long periods. Typical symptoms such as chronic cough, difficulty breathing, coughing up blood, weight loss and a lack of appetite are usually only recognized as symptoms of lung cancer when it has already reached an advanced stage at which a cure is no longer possible. Among the most important risk factors that can trigger lung cancer are active and passive smoking. However, other substances such as radon, asbestos, radioactive dust and the like are also considered to trigger cancer. The onset of lung cancer can also be favored by high levels of air pollution, existing pre-existing lung conditions, and genetic predisposition.

Risks and side effects

Because treatment with afatinib can result in side effects – some of them serious – careful monitoring is necessary during the first six weeks after starting treatment. This is especially true if diarrhea occurs. These can be very severe and, in extreme cases, can even lead to dehydration if the patient does not consume plenty of fluids to compensate.In addition, the most common side effects include severe skin reactions, which can be exacerbated under the influence of ultraviolet radiation. Patients should protect themselves from the sun and not use a tanning bed. The side effects of afatinib can manifest themselves in a variety of medical conditions, so further treatment must be given under special medical supervision.