What is panitumumab?

Panitumumab (Vectibix®) is used to treat bowel cancer that has spread to other parts of the body. It is best to read this information with our general information about the type of cancer you have. 

Panitumumab belongs to a group of targeted therapy drugs known as monoclonal antibodies. It also works as a cancer growth inhibitor.

Panitumumab only works on bowel cancers that have a normal RAS gene. The RAS gene helps control cell growth. Before panitumumab is used, doctors test the bowel cancer cells for changes (mutations) in this gene.

Your doctor will talk to you about this treatment and its possible side effects before you agree (consent) to have treatment.

How panitumumab is given

You will be given panitumumab at a day unit as an outpatient. Panitumumab is usually given in combination with other cancer drugs. It is sometimes given on its own if you have already had chemotherapy.

During treatment you usually see a cancer doctor, a cancer nurse or specialist nurse, and a specialist pharmacist. This is who we mean when we mention doctor, nurse or pharmacist in this information.

Before or on the day of treatment, a nurse or person trained to take blood (phlebotomist) will take a blood sample from you. This is to check that your blood cells are at a safe level to have treatment. 

You will see a doctor or nurse before you have treatment. They will ask you how you have been feeling. If your blood results are okay, the pharmacist will prepare your targeted therapy. Your nurse will tell you when your treatment is likely to be ready. 

Panitumumab is given as a drip into a vein (intravenous infusion). You have the first infusion slowly, usually over about 60 minutes. If you do not have any problems, you can have your next treatment over 30 to 60 minutes.

Some people may have higher doses of panitumumab. These infusions are given over about 90 minutes. You usually have panitumumab once every 2 weeks.

About side effects

We explain the most common side effects of this treatment here. We also include some less common side effects.

You may get some of the side effects we mention, but you are unlikely to get all of them. If you are also having treatment with other cancer drugs, you may have some side effects that we have not listed here. Always tell your doctor, nurse or pharmacist about any side effects you have.

Your doctor can give you drugs to help control some side effects. It is important to take them exactly as your nurse or pharmacist explains. This means they will be more likely to work for you. Your nurse will give you advice about managing your side effects. After your treatment is over, most side effects start to improve.

Serious and life-threatening side effects

Some cancer treatments can cause severe side effects. Rarely, these may be life-threatening. Your cancer doctor or nurse can explain the risk of these side effects to you.

Contact the hospital

Your nurse will give you telephone numbers for the hospital. If you feel unwell or need advice, you can call them at any time of the day or night. Save these numbers in your phone or keep them somewhere safe.

More information

We cannot list every side effect for this treatment. There are some rare side effects that are not listed. You can visit the electronic Medicines Compendium (eMC) for more detailed information.

Side effects while treatment is being given

Allergic reaction

Some people have an allergic reaction while having this treatment. Before treatment, you will be given medicines to help prevent or reduce any reaction.

Signs of a reaction can include:

  • feeling hot or flushed
  • a skin rash
  • itching
  • shivering
  • feeling dizzy
  • a headache
  • feeling breathless 
  • swelling of your face or lips
  • pain in your back, tummy or chest. 

Your nurse will check you for signs of a reaction during your treatment. If you feel unwell or have any of these signs, tell them straight away. If you do have a reaction, it can be treated quickly. 

Sometimes a reaction can happen after treatment. If you develop any signs or feel unwell after you get home, contact the hospital straight away.

Common side effects of panitumumab

Skin and nail changes

Most people having panitumumab will have skin changes during treatment.

The most common side effect is an acne-like rash on the face, neck and body. This usually begins during the first 2 or 3 weeks of treatment. It usually goes away a few weeks after treatment ends.

Your skin may also become dry, itchy or scaly, and it may feel tender. The skin around your nails may become red and sore. Your nails may become brittle and break.

Very rarely, people may have a severe skin reaction. The symptoms can include large blisters, peeling skin or sores in the mouth. You may also have a fever (high temperature). Contact the hospital straight away if this happens.

Always tell your doctor or nurse about any skin changes. They can give you advice and prescribe creams or medicines to help. If you are out in the sun, use a sun cream with a high sun protection factor (at least SPF 30) to protect your skin.

If you have severe skin problems, your doctor may suggest a longer time between treatments or a lower dose of panitumumab.

Risk of infection

This treatment can reduce the number of white blood cells in your blood. These cells fight infection.

If the number of white blood cells is low, you are more likely to get an infection. A low white blood cell count is called neutropenia.

If you have an infection, it is important to treat it as soon as possible. Contact the hospital straight away on the 24-hour contact number you have if:

  • your temperature goes over 37.5°C (99.5°F)
  • you suddenly feel unwell, even with a normal temperature
  • you have symptoms of an infection.

Symptoms of an infection include:

  • feeling shivery
  • a sore throat
  • a cough
  • diarrhoea
  • needing to pass urine often.

It is important to follow any specific advice your cancer treatment team gives you.

The number of white blood cells will usually return to normal before your next treatment. You will have a blood test before having more treatment. If your white blood cell count is low, your doctor may delay your treatment for a short time.

Anaemia (low number of red blood cells)

This treatment can reduce the number of red blood cells in your blood. These cells carry oxygen around the body. If the number of red blood cells is low, you may be tired and breathless. Tell your doctor or nurse if you feel like this. If you are very anaemic, you may need a drip to give you extra red blood cells. This is called a blood transfusion.

Feeling sick

You may feel sick in the first few days after this treatment. Your doctor will give you anti-sickness drugs to help prevent or control sickness. Take the drugs exactly as your nurse or pharmacist tells you. It is easier to prevent sickness than to treat it after it has started.

If you feel sick, take small sips of fluids and eat small amounts often. If you continue to feel sick, or if you vomit more than once in 24-hours, contact the hospital as soon as possible. They will give you advice and may change the anti-sickness drug to one that works better for you.

Diarrhoea

This treatment may cause diarrhoea. Diarrhoea means passing more stools (poo) than is usual for you, or having watery or loose stools. If you have a stoma, it will be more active than usual.

If you have diarrhoea:

  • try to drink at least 2 litres (3½ pints) of fluids each day
  • avoid alcohol, caffeine, milk products, high-fat foods and high-fibre foods
  • contact the hospital for advice.

Constipation

This treatment can cause constipation. Here are some tips that may help:

  • Drink at least 2 litres (3½ pints) of fluids each day.
  • Eat high-fibre foods, such as fruit, vegetables and wholemeal bread.
  • Do regular gentle exercise, like going for short walks.

If you have constipation, contact the hospital for advice. Your doctor can give you drugs called laxatives to help.

Feeling tired

Feeling tired is a common side effect. It is often worse towards the end of treatment and for some weeks after it has finished. Try to pace yourself and plan your day so you have time to rest. Gentle exercise, like short walks, can give you more energy. If you feel sleepy, do not drive or operate machinery.

Sore mouth

You may get a sore mouth or mouth ulcers. This can make you more likely to get a mouth infection.

Use a soft toothbrush to clean your teeth or dentures in the morning, at night and after meals.

If your mouth is sore:

  • tell your nurse or doctor – they can give you a mouthwash or medicines to help
  • try to drink plenty of fluids
  • avoid alcohol, tobacco, and foods that irritate your mouth.

Hair changes

Your eyelashes may grow longer and more curly than usual. Men may notice less beard growth. You may notice your head and body hair is finer, curlier or more brittle. Some people may lose their hair slowly over several months. These changes are usually temporary and gradually improve once treatment is over. 

Effects on the eyes

Your eyes may water and feel sore. They may become more sensitive to light. Your doctor can give you eye drops to help with this. If your eyes get red and inflamed (conjunctivitis), tell your doctor. You may need antibiotic eye drops. Panitumumab may also cause blurred vision. Always tell your doctor or nurse if your eyes are painful or if there is a change in your vision.

Effects on the lungs

This treatment can cause changes to the lungs. Tell your doctor if you develop:

  • a cough
  • wheezing
  • a fever (high temperature)
  • breathlessness.

You should also tell them if any existing breathing problems get worse. You may have tests to check your lungs.

Indigestion or loss of appetite

Some people have indigestion or acid reflux. Acid reflux is when acid comes up from the stomach into the gullet (oesophagus). Tell your doctor if this happens. They can give you treatment to help.

During treatment, you may lose your appetite. Try to eat small meals regularly. If your appetite does not improve after a few days, let your nurse or dietitian know. They can give you advice on improving your appetite and keeping to a healthy weight.

Reduced levels of magnesium, potassium or calcium in the blood

You will have regular blood tests to check this. If the levels are too low, your doctor may prescribe supplements.

Back pain

Some people have back pain while having treatment with panitumumab. If this becomes a problem, ask your doctor for advice about painkillers.

Less common side effects of panitumumab

Fluid build-up

You may gain weight, or your face, ankles and legs may swell. This improves slowly after your treatment has finished. Your doctor may give you drugs to help reduce the swelling.

Difficulty sleeping and anxiety

Some people have problems sleeping or feel anxious during treatment. Tell your doctor or nurse if this happens.

Sore and red hands and feet

Having sore and red palms of hands and soles of feet is called palmar-plantar or hand-foot syndrome. Your doctor or nurse can give you advice and prescribe creams to improve the symptoms. It can help to keep your hands and feet cool and avoid tight-fitting socks, shoes and gloves. Tell your nurse about any changes in your hands or feet.

Raised blood sugar levels

This treatment may raise your blood sugar levels. You will have regular blood tests to check this. Symptoms of raised blood sugar include:

  • feeling thirsty
  • needing to pass urine (pee) more often
  • feeling tired.

Tell your doctor or nurse if you have these symptoms during treatment or after it finishes.

If you have diabetes, your blood sugar levels may be higher than usual. Your doctor will talk to you about how to manage this.

Blood clot risk

Cancer and some cancer treatments can increase the risk of a blood clot. Symptoms of a blood clot include:

  • pain, redness or swelling in a leg or arm
  • breathlessness
  • chest pain.

If you have any of these symptoms, contact a doctor straight away.

A blood clot is serious, but can be treated with drugs that thin the blood. Your doctor or nurse can give you more information.

Changes in blood pressure

Your blood pressure may become higher or lower than normal. Tell your nurse or doctor if you have headaches or feel dizzy. These can be signs of blood pressure changes.

Other information

Other medicines

Some medicines can affect this treatment or be harmful when you are having it. This includes medicines you can buy in a shop or chemist. Tell your cancer doctor about any drugs you are taking, including vitamins, herbal drugs and complementary therapies.

Vaccinations

Your doctor or nurse may talk to you about vaccinations. These help reduce your risk of getting infections.

Doctors usually recommend that you have a flu jab, which is an inactivated vaccination. People with weak immune systems can have this type of vaccination.

If your immune system is weak, you need to avoid live vaccinations such as shingles. Your cancer doctor or GP can tell you more about live vaccinations.

Fertility

Some cancer drugs can affect whether you can get pregnant or make someone pregnant. If you are worried about this, it is important to talk with your doctor before you start treatment.

Contraception

Your doctor will advise you not to get pregnant or make someone pregnant while having this treatment. The drugs may harm a developing baby. It is important to use contraception during your treatment and for a while after treatment finishes. Your doctor, nurse or pharmacist can tell you more about this.

Breastfeeding

Women are advised not to breastfeed during treatment and for 2 months after. This is in case there is any of the drug in their breast milk.

Driving

If panitumumab affects your concentration or vision, do not drive while on this treatment.

Medical and dental treatment

If you need medical treatment for any reason other than cancer, always tell the doctors and nurses that you are having cancer treatment. Give them the contact details for your cancer doctor so they can ask for advice.

If you think you need dental treatment, talk to your cancer doctor or nurse. Always tell your dentist you are having cancer treatment.