Cancer drugs A to Z list
Avelumab is a type of . It is a treatment for:
a type of skin cancer called Merkel cell carcinoma (MCC) that has spread to other parts of the body. Doctors call cancer that has spread elsewhere in the body advanced cancer
or advanced urothelial cancer which hasn’t grown after treatment with chemotherapy
Urothelial cancers include cancers of the:
part of the kidney called the renal pelvis
ureters - the tubes that carry the urine from the kidneys to the bladder
bladder
urethra - the tube that carries the urine from your bladder out of your body
Urothelial cancers of the renal pelvis and ureter are called upper urinary tract urothelial cancers.
Some people may have avelumab combined with a called axitinib. This is a treatment for a type of kidney cancer called renal cell carcinoma (RCC) that has spread.
You might have avelumab as part of a for other cancer types.
Find out more about these types of cancer from our A to Z list
Avelumab is a type of immunotherapy called a . It blocks proteins that stop the immune system from attacking the cancer cells. This allows the immune cells to kill the cancer cells.
Avelumab targets and blocks a protein called PD-L1 on the surface of cancer cells. Blocking PD-L1 helps your to find and kill cancer cells.
Find out more about checkpoint inhibitors
You have avelumab as a drip into your bloodstream (intravenously). It takes about an hour each time you have it.
You might have treatment through a long plastic tube that goes into a large vein in your chest. The tube stays in place throughout the course of treatment. This can be a:
central line
PICC line
portacath
You might have treatment through a thin short tube (a cannula) that goes into a vein in your arm. You have a new cannula each time you have treatment.
Read about having cancer drugs into your bloodstream
You have avelumab every 2 weeks.
You have avelumab for as long as it is working and you are not experiencing too many side effects. If you are having avelumab for urothelial cancer, you may stop it after 5 years.
You usually have paracetamol and an antihistamine drug before the first 4 avelumab treatments. This reduces your risk of having an allergic reaction during treatment. Some people may continue to have them before further treatments.
You have blood tests before and during your treatment. They check your levels of and other substances in the blood. They also check how well your liver, and kidneys are working.
Before treatment starts you may have a blood test to check for viruses such as hepatitis B, hepatitis C, and HIV. This is called a viral screen.
It’s important for your doctor to know if you have had any of these viruses. This is because this treatment can weaken your and can cause the virus to become active again (reactivation).
Side effects can vary from person to person. They also depend on what other treatment you are having.
Your doctor, pharmacist or nurse will go through the possible side effects. They will monitor you closely during treatment and check how you are at your appointments. Contact your advice line as soon as possible if:
you have severe side effects
your side effects aren’t getting any better
your side effects are getting worse
Early treatment can help manage side effects better.
We haven't listed all the side effects here. Talk to your healthcare team if you have any new symptoms that you think might be a side effect of your treatment.
Remember it is very unlikely that you will have all of these side effects, but you might have some of them at the same time.
These side effects happen in more than 10 in 100 people (more than 10%). You might have one or more of them. They include:
A reaction may happen during the infusion. Symptoms can include a skin rash, itching, swelling of the lips, face or throat, breathing difficulties, fever and chills. Your nurse will give you medicines beforehand to try to prevent a reaction.
You might be breathless and look pale due to a drop in . This is called anaemia.
Tiredness and weakness (fatigue) can happen during and after treatment. Doing gentle exercises each day can keep your energy up. Don't push yourself, rest when you start to feel tired and ask others for help.
Let your doctor know if you are more tired than usual.
Feeling or being sick is usually well controlled with anti sickness medicines. It might help to avoid fatty or fried foods, eat small meals and snacks and take regular sips of water. Relaxation techniques might also help.
It is important to take anti sickness medicines as prescribed even if you don’t feel sick. It is easier to prevent sickness rather than treat it once it has started.
You might get diarrhoea. Try to eat small meals and snacks regularly. It’s best to try to have a healthy balanced diet if you can. You don’t necessarily need to stop eating foods that contain fibre. But if your diet is normally very high in fibre, it might help to cut back on high fibre foods such as beans, nuts, seeds, dried fruit, bran and raw vegetables.
Drink plenty to try and replace the fluid lost. Aim for 8 to 10 glasses per day.
Your bowel may also become inflamed and swollen. This can be serious.
is easier to sort out if you treat it early. Drink plenty and eat as much fresh fruit and vegetables as you can. Try to take gentle exercise, such as walking. Tell your healthcare team if you think you are constipated. They can give you a if needed.
You might not feel like eating and may lose weight. Eating several small meals and snacks throughout the day can be easier to manage. You can talk to a dietitian if you are concerned about your appetite or weight loss.
You might develop a cough or breathing problems. Less commonly this can be due to inflammation of the lungs (pneumonitis). Rarely a cough or breathing problems can be due to changes in your lung tissue.
Let your doctor or nurse know straight away if you become breathless or develop a cough.
Contact your advice line if you have this. Depending on what is causing the pain, they might give you medicine to help.
Let your doctor know if you have pain in your back or joints. There are lots of ways to treat pain, including painkillers and relaxation.
Less commonly you might getting swelling in your joints.
Tell your healthcare team straightaway if you get a high temperature. Ask them if you can take paracetamol to help lower your temperature.
Swelling of hands and feet is due to fluid build up. Doctors call this oedema. Let your doctor or nurse know if you have any swelling.
These side effects happen in between 1 and 10 out of every 100 people (between 1 and 10%). You might have one or more of them. They include:
low levels of in your body which can increase your risk of getting an infection. Rarely the levels may be high
a drop in the level of in your body which can increase your risk of bruising, bleeding and nosebleeds
headaches or dizziness - tell your doctor or nurse if you have these symptoms
numbness and tingling in fingers and toes which can make it difficult doing up buttons
changes to the levels of thyroid in your body - low levels can make you feel tired and cold, high levels can cause symptoms including heart palpitations, anxiety and mood swings
high blood pressure - symptoms can include blurred vision, nosebleeds, dizziness, headaches, shortness of breath and chest pain
dry mouth
skin changes including itching, dry skin and a rash which might be flat or raised bumps
pain in your muscles
flu like symptoms such as shivering, chills and feeling generally unwell
higher levels of liver and pancreas - this can be temporary but some people may need treatment
high levels of a waste product made by the muscles. You have blood tests to check these levels
low levels of sodium in your blood
These side effects happen in fewer than 1 in 100 people (less than 1%). You might have one or more of them. They include:
low blood pressure – you might feel dizzy, lightheaded or faint
high blood sugar levels (diabetes)
inflammation in different parts of your body such as the heart muscle, thyroid, eyes, liver, pancreas, rectum, bladder and kidneys - you may need to take or other treatments to help manage these side effects
low levels of different hormones in your body
muscle weakness in different parts of the body (myasthenia gravis)
the skin of your face, neck and chest may look red (flushed)
ileus - slowing or stopping of the bowels which can cause severe constipation, stomach pain, feeling or being sick and bloating
kidneys or liver stop working properly. You have blood tests to check for this
long term problems caused by inflammation of some organs and tissues. The most common site is the lungs (sarcoidosis)
the immune system attacking the nervous system (Guillain-Barré syndrome) - causing numbness, weakness and pain in the body. Go to A&E if you have any numbness or are unable to move
a serious reaction that causes inflammation in your whole body – symptoms include a low or high temperature, breathing quickly and your heart beating very fast. Call 999 or go to accident and emergency (A&E) immediately if you have any of these symptoms
There isn't enough information to work out how often these side effects might happen. You might have one or more of them. They include:
inflammation of the stomach or
a condition called polymyalgia rheumatica – this causes pain and stiffness in your hips, shoulders and neck
We have more information about side effects and tips on how to cope with them.
Cancer drugs can interact with medicines, herbal products, and some food and drinks. We are unable to list all the possible interactions that may happen. An example is grapefruit or grapefruit juice which can increase the side effects of certain drugs.
Tell your healthcare team about any medicines you are taking. This includes vitamins, herbal supplements and over the counter remedies. Also let them know about any other medical conditions or allergies you may have.
It is not known whether this treatment affects in people. Talk to your doctor before starting treatment if you think you may want to have a baby in the future.
This drug may harm a baby developing in the womb. It is important not to become pregnant or get someone pregnant while you are having treatment with this drug and for at least 1 month afterwards.
Talk to your doctor or nurse about effective contraception before starting treatment. Let them know straight away if you or your partner become pregnant while having treatment.
It is not known whether this drug comes through into the breast milk. Doctors usually advise that you don’t breastfeed during this treatment and for at least 1 month afterwards.
If you are having tests or treatment for anything else, always mention your cancer treatment. For example, if you are visiting your dentist.
Do not have live vaccines while you’re having treatment and for up to 12 months afterwards. For some people, it may be longer than this. The length of time you need to avoid live vaccines depends on the treatment you’ve had.
Ask your doctor or pharmacist how long you should avoid live vaccinations.
In the UK, live vaccines include rubella, mumps, measles, chickenpox, BCG, and yellow fever. You can usually have non-live vaccines. But they might not give you as much protection as usual. These include the:
flu vaccine, as an injection
coronavirus (COVID-19) vaccine
Talk to your doctor or pharmacist about the best time to have a vaccine in relation to your cancer treatment.
You can be in contact with other people who have had live vaccines as injections. If someone has had a live vaccine by mouth or nasal spray there may be a small risk the vaccine virus can be passed onto you if your is weakened.
Your healthcare team will let you know if you need to take any precautions if you are in close contact with someone who has had a live vaccine.
For further information about this treatment and possible side effects go to the electronic Medicines Compendium (eMC) website. You can find the patient information leaflet on this website.
You can report any side effect you have to the Medicines and Healthcare products Regulatory Agency (MHRA) as part of their Yellow Card Scheme.
Last reviewed: 09 Sept 2026
Next review due: 09 Sept 2029
Immunotherapy uses our immune system to fight cancer. It works by helping the immune system recognise and attack cancer cells.
Merkel cell carcinoma (MCC) is a type of skin cancer that starts in Merkel cells. These are a type of neuroendocrine cell so MCC is also called a neuroendocrine carcinoma (NEC).
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