EGFR, or epidermal growth factor receptor, is a type of molecule found on the surface of cells in the body. Sometimes this protein changes or mutates and becomes too active. If it does mutate, that means certain cells are being told to grow and spread faster than they should. This leads to cancer. If your doctor finds an EGFR biomarker using a biopsy or a blood test, this means an EGFR mutation is making your cancer grow.^1-4

Non-small cell lung cancer with an EGFR biomarker is known as EGFR+ NSCLC. The EGFR biomarker is found in people with NSCLC and ranges from 10% to 15% in Caucasian patients and up to 60% in East-Asian patients.⁵ The EGFR biomarker is found mostly in patients with adenocarcinoma*, and is more frequent in women, patients who never smoked or used to smoke lightly, and patients of East Asian origin⁶

*adenocarcinoma is a subtype of NSCLC. It is usually found in the outer parts of the lung and is more likely to be found before it has spread to other parts of the body⁷

When a cancer treatment stops working, this may be because the tumours become resistant to the targeted therapy being used (often an EGFR tyrosine kinase inhibitor or TKI). If this happens, your lung cancer will grow or spread (which is known as progression). When EGFR+ NSCLC becomes resistant to specific EGFR TKIs, it could be due to another mutation called T790M.^8-10

Testing for biomarkers is an important part of your lung cancer diagnosis. Biomarker testing is done as either a biopsy (where tissue is removed from a tumour so it can be tested) or a blood test (also known as a liquid biopsy). Your doctor will decide which test is right for you. Finding out which biomarker you may have, such as EGFR, can help determine the treatment options that may give you the optimal results for your type of lung cancer. Biomarker testing is sometimes referred to as genetic testing, molecular testing, or mutation testing.^4,11

Targeted therapies are treatments designed for specific types of cancer. They are not chemotherapy or immunotherapy. Targeted therapies help stop the growth and spread of cancer cells, and cause them to die.^12-15

Osimertinib is a prescription medicine used to treat adults with specific types of non-small cell lung-cancer (NSCLC) that has certain abnormal epidermal growth factor receptor (EGFR) gene(s):^16-17

• to help prevent your lung cancer from coming back after your tumour(s) has been removed by surgery, or
• as your first treatment when your lung cancer has spread to other parts of the body (locally advanced or metastatic), or
  
• when your lung cancer has spread to other parts of the body (locally advanced or metastatic) and you have had previous treatment that didn't work.

Your healthcare provider will perform a test to find out if osimertinib is an appropriate treatment for you. Refer to the ‘What is osimertinib’ page for more information.

• this is a summary of side effects
• for more detailed information you must read the patient information leaflet found inside the box your osimertinib came in
• refer to the ‘Safety Considerations' page for more information on potential side effects.

Osimertinib may cause serious side effects, including:¹⁶

• lung problems. Osimertinib may cause lung problems. Symptoms may be similar to symptoms from lung cancer. Tell your healthcare provider right away if you have any new or worsening lung symptoms, including trouble breathing, shortness of breath, cough, and fever
  
  
• heart problems. Osimertinib may cause heart problems. Your healthcare provider should check your heart function before you start taking osimertinib and during treatment as needed. Tell your healthcare provider right away if you have any of the following signs and symptoms of a heart problem: feeling like your heart is pounding or racing, shortness of breath, swelling of your ankles and feet, feeling lightheaded, chest discomfort and fainting
  
  
• eye problems. Osimertinib may cause eye problems. Tell your healthcare provider right away if you have symptoms of eye problems which may include watery eyes, sensitivity to light, eye pain, eye redness, or vision changes. Your healthcare provider may send you to see an eye specialist (ophthalmologist) if you get eye problems with osimertinib
  
  
• skin problems. Osimertinib may cause skin problems. Tell your healthcare provider right away if you develop target lesions (skin reactions that look like rings), severe blistering or peeling of the skin, ulcers of mouth, throat, nose, genitals and eyes that may follow fever and flu-like symptoms
  
  
• Hepatitis B. Osimertinib could cause hepatitis B virus to become active again if you have had an infection before. Tell your cancer care team if you get worsening tiredness or yellowing of your skin or white part of your eyes

The most common side effects of osimertinib are:¹⁶

• itchy skin
  
• low white blood cell count
  
• low platelet count
  
• diarrhoea
  
• low red blood cell count (anaemia)
  
• rash
• changes in your nails, including redness, tenderness, pain, inflammation, brittleness, separation from nailbed, and shedding of nail
  
• dry skin
  
• mouth sores

Tell your cancer care team if you have any side effect that bothers you or that does not go away.

These are not all the possible side effects of osimertinib. If in doubt, speak to your cancer care team. For more information on reporting side effects, refer here.

Before taking osimertinib, tell your healthcare provider about all of your medical conditions, including if you:^16,17

• have suffered from inflammation of lungs (a condition called ‘interstitial lung disease’) or sudden difficulty in breathing together with a cough or fever
  
• have ever had heart problems, including a condition called long QTc syndrome
• have a history of eye problems
  
• are pregnant, think you may be pregnant or are planning to have a baby, ask your doctor for advice before taking this medicine. If you do become pregnant during treatment, tell your doctor straight away. Your doctor will decide with you whether you should carry on taking Osimertinib
  Females who can become pregnant should have a pregnancy test before starting treatment with osimertinib. You should use effective birth control during treatment with osimertinib and for at least 2 months after the final dose of osimertinib
  Males who have female partners that are able to become pregnant should use effective birth control during treatment with osimertinib and for at least 4 months after the final dose of osimertinib
  
• are breastfeeding or plan to breastfeed. It is not known if osimertinib passes into your breast milk. Do not breast-feed while taking this medicine. This is because it is not known if there is a risk to your baby. Talk to your healthcare provider about the best way to feed your baby during this time
• If you have ever had or might now have a hepatitis B infection, please tell your doctor or healthcare professional. This is because osimertinib could cause hepatitis B virus to become active again. Talk to your doctor or nurse and you will be monitored more closely and specifically to check this and treatment may, if necessary, be stopped.

Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, or herbal supplements. Especially tell your healthcare provider if you take a heart or blood pressure medicine

Refer to the 'Safety Considerations' page for more information on potential side effects.

Osimertinib is a pill you take once a day. Take it with or without food, at the same time every day.^17,18 Swallow the tablet whole with water. Do not crush, split or chew the tablet.¹⁷

Please consult your patient information leaflet inside the box your osimertinib came in on detailed instructions on how to take this medicine.