Panitumumab is a type of targeted cancer drug Open a glossary item called a monoclonal antibody Open a glossary item . It’s also known by its brand name, Vectibix.

You pronounce panitumumab as pan-i-too-moo-mab.

You might have it as a treatment for bowel cancer that has spread to other areas of the body (advanced).

Panitumumab is sometimes combined with other chemotherapy treatments such as:

  • FOLFIRI

  • FOLFOX

How does panitumumab work?

Panitumumab works by blocking signals that tell cancer cells to divide and grow. It attaches to a specific protein called epidermal growth factor Open a glossary item receptor (EGFR) found on the surface of some cancer cells.

Panitumumab only works on bowel cancers that have a normal Ras gene Open a glossary item . You will have tests to check that your bowel cancer has the normal version of this gene.

How do you have panitumumab?

You have panitumumab as a drip into a vein (intravenously).

You 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

How often do you have panitumumab?

You have panitumumab every 2 weeks. The first treatment takes about 60 to 90 minutes. If you don't have any problems treatments after that it takes about 30 to 60 minutes.

You usually have panitumumab for as long as it is helping you and the side effects aren't too bad.

Tests

You have blood tests before and during your treatment. They check your levels of blood cells and other substances in the blood. They also check how well your liver and kidneys are working.

What are the side effects of panitumumab?

How often and how severe the side effects are can vary from person to person. They also depend on what other treatment you are having.

When to contact your team

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
  • the side effects are affecting your daily life

Early treatment can help manage side effects better.

Contact your advice line, doctor or nurse immediately if you have signs of infection, such as a temperature above 37.5C or below 36C, or if you develop a severe skin reaction. Signs of a severe skin reaction include peeling or blistering of the skin.

We haven't listed all the side effects here. 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.

Common side effects

These side effects happen in more than 10 in 100 people (more than 10%). You might have one or more of them. They include:

Skin reaction

Nearly everyone who has panitumumab will have a skin reaction. The reaction usually starts about 10 days after the start of treatment and gets better within a month of finishing treatment.

You might notice

skin changes

, such as dryness, itching and rashes similar to acne on your face, neck and trunk.

Tell your doctor if you have any rashes or itching. Don't go swimming if you have a rash because the chlorine in the water can make it worse.

If your skin gets dry or itchy, smoothing in unperfumed moisturising cream may help. Check with your doctor or nurse before using any creams or lotions.

Your skin is more sensitive to sunlight during your treatment and for several months afterwards. You need to cover up and stay in the shade. Wear a high factor sun block if you’re going out in the sun. Sunlight can make skin reactions worse.

Breathlessness and looking pale

You might be

breathless and look pale

due to a drop in red blood cells. This is called anaemia.

Sore mouth

Mouth sores and ulcers

can be painful. It helps to keep your mouth and teeth clean, drink plenty of fluids and avoid acidic foods such as lemons. Chewing gum can help to keep the mouth moist. Tell your doctor or nurse if you have ulcers.

You might have a dry mouth and dry, chapped lips but this is less common.

Nail infection

Your nails might become infected. Tell your doctor or nurse if this happens.

Your nails can break easily or become loose but this is less common.

Tiredness and weakness

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.

Diarrhoea or constipation

Tell your healthcare team if you have

diarrhoea or constipation

. They can give you medicine to help.

Feeling or being sick

Feeling or being sick

is usually well controlled with anti sickness medicines. Avoiding fatty or fried foods, try eating small meals and snacks, drinking plenty of water, and relaxation techniques can all 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.

Sore eyes

You might have eye problems, such as conjunctivitis.

Let your doctor or nurse know if you have any problems with your eyes. They can give you eye drops to help.

Loss of appetite and weight loss

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.

Low levels of minerals in your blood

You might have changes in levels of minerals and salts in your blood, such as low magnesium and potassium.

You have regular blood tests during treatment to check this.

Let your doctor or nurse know if you have cramping in your arm or leg muscles, tingling or numbness, palpitations (feeling your heart beat irregularly), or if you feel faint.

Hair loss

You could

lose all your hair

. This includes your eyelashes, eyebrows, underarms, legs and sometimes pubic hair. Your hair will usually grow back once treatment has finished but it is likely to be softer. It may grow back a different colour or be curlier than before.

Other less common side effects are:

  • your eyelashes might become thicker or longer
  • you might grow more hair on your face and body

Tummy (abdominal) pain

Tell your treatment team if you have this. They can check the cause and give you medicine to help.

Swollen hands and feet

Swelling of hands and feet is due to fluid build up. This is called oedema. Let your doctor or nurse know if you have any swelling.

You might have swelling in the deep layers of your skin but this is much less common.

High temperature (fever)

If you get a high temperature, let your healthcare team know straight away. Ask them if you can take paracetamol to help lower your temperature.

Back pain

You might have back pain. Speak to your doctor if this is a problem for you. They can prescribe medicine to help.

You might have chest, arm and leg pain but this is less common.

Difficulty sleeping

If you have difficulty sleeping, it can help to change a few things about how you try to sleep. Try to go to bed and get up at the same time each day and spend some time relaxing before you go to bed. Some light exercise each day may also help.

Cough and difficulty breathing

You may have difficulty breathing with wheezing and coughing. Let your healthcare team know straight away if this happens.

You might have inflammation of the lungs or tightening of the muscles of the airways but this is much less common.

Occasional side effects

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:

  • increased risk of getting an infection due to low white blood cells
  • an allergic reaction that can cause a rash, shortness of breath, redness or swelling of the face and dizziness. Some allergic reactions can be life threatening, alert your nurse or doctor if notice any of these symptoms.
  • blood clots that are life threatening; signs are pain, swelling and redness where the clot is. Feeling breathless can be a sign of a blood clot on the lung. Contact your advice line or doctor straight away if you have any of these symptoms.
  • headaches
  • dizziness
  • feeling anxious
  • soreness, redness and peeling hands and feet
  • not enough fluid in the body (dehydration)
  • sweating more than usual
  • indigestion and heartburn
  • high blood sugar levels
  • changes to your blood pressure causing it to go too high or too low
  • a fast heart rate
  • chills
  • dry mouth
  • nose bleeds and bleeding from the back passage (rectum)

Rare side effects

These side effects happen in fewer than 1 in 100 people (fewer than 1%). You might have one or more of them. They include

  • a severe skin reaction that may start as tender red patches which leads to peeling or blistering of the skin. You might also feel feverish and your eyes may be more sensitive to light. This is serious and could be life threatening.
  • dry nostrils
  • chills, fever and shortness of breath happening within 24 hours after the infusion. Contact the advice line or a member of the healthcare team if you have any of these symptoms.
  • a feeling of tightness in the chest caused by the muscle lining the airways in the lungs tightening
  • scarring of the lungs

Coping with side effects

We have more information about side effects and tips on how to cope with them.

What else do you need to know?

Other medicines, foods and drink

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.

Pregnancy and contraception

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 2 months afterwards.

Talk to your doctor or nurse about effective contraception before starting treatment. Let them know straight away if you or your partner falls pregnant while having treatment.

Loss of fertility

You may not be able to become pregnant or get someone pregnant after treatment with this drug. Talk to your doctor before starting treatment if you think you may want to have a baby in the future.

Men might be able to store sperm before starting treatment. And women might be able to store eggs or ovarian tissue. But these services are not available in every hospital, so you would need to ask your doctor about this.

Breastfeeding

Do not breastfeed during this treatment and for at least 2 months afterwards. The drug may come through in the breast milk.

Treatment for other conditions

Always tell other doctors, nurses, pharmacists or dentists that you’re having this treatment. For example, if you need treatment for anything else, including teeth problems.

Immunisations

Don’t have immunisations with live vaccines while you’re having treatment and for up to 12 months afterwards. The length of time depends on the treatment you are having. Ask your doctor or pharmacist how long you should avoid live vaccinations.

In the UK, live vaccines include rubella, mumps, measles, BCG, yellow fever and one of the shingles vaccines called Zostavax.

You can have:

  • other vaccines, but they might not give you as much protection as usual
  • the flu vaccine (as an injection)
  • the coronavirus (COVID-19) vaccine - talk to your doctor or pharmacist about the best time to have it in relation to your cancer treatment

Members of your household who are aged 5 years or over are also able to have the COVID-19 vaccine. This is to help lower your risk of getting COVID-19 while having cancer treatment and until your immune system Open a glossary item recovers from treatment.

Contact with others who have had immunisations - You can be in contact with other people who have had live vaccines as injections. Avoid close contact with people who have recently had live vaccines taken by mouth (oral vaccines) such as the oral typhoid vaccine. Sometimes people who have had the live shingles vaccine can get a shingles type rash. If this happens they should keep the area covered.

If your immune system is severely weakened, you should avoid contact with children who have had the flu vaccine as a nasal spray as this is a live vaccine. This is for 2 weeks following their vaccination.

Babies have the live rotavirus vaccine. The virus is in the baby’s poo for about 2 weeks and could make you ill if your immunity is low. Get someone else to change their nappies during this time if you can. If this isn't possible, wash your hands well after changing their nappy.

More information about this treatment

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 Health and Regulatory Authority (MHRA) as part of their Yellow Card Scheme.