Panitumumab (Vectibix)

Panitumumab is pronounced pan-ee-chew-moo-mab. It is also known by its brand name Vectibix. It is a type of monoclonal antibody. Monoclonal antibodies are a type of biological therapy.

Panitumumab is a treatment for advanced bowel cancer when other treatments are no longer working. Advanced cancers have spread from where they started to another part of the body. You may also have panitumumab as part of trials for other cancers. It is sometimes combined with other treatments such as chemotherapy. 

Panitumumab only works on cancers that have a normal Kras gene. This gene helps to control how cells grow and divide. You will need to have tests to check if this gene is normal.

Some cancer cells have proteins called epidermal growth factor receptors (EGFR) on their surface. Epidermal growth factor (EGF) is another type of protein made naturally in the body that attaches to this receptor. This triggers the cell to grow and divide into more cells. Panitumumab works by attaching itself to the EGF receptors to block EGF protein from reaching the cancer cells. It also helps the immune system to recognise the cancer cells so that it can destroy them.

Panitumumab works better if your cancer cells have a lot of epidermal growth factor receptors. Before you have panitumumab, you may have tests to check the amount of epidermal growth factor receptors.

You have panitumumab through a drip into a vein (infusion). The rate of the drip is controlled by a pump. You can have the drug through a thin, short tube (a cannula) put into a vein in your arm each time you have treatment. Or you may have it through a central line, a portacath or a PICC line. These are long, plastic tubes that give the drugs directly into a large vein in your chest. You have the tube put in just before your course of treatment starts and it stays in place as long as you need it.

The first treatment takes about 60 to 90 minutes. After that you have treatment every 2 weeks and it takes about 30 to 60 minutes. You usually have it for a few months or as long as it is working.

The side effects associated with panitumumab are listed below. You can click on the underlined links to find out about managing the side effects or you can go to our cancer drug side effects section. The side effects may be different if you are having panitumumab with other drugs.

More than 10 in every 100 people have one or more of these.

• A skin reaction occurs in 9 out of 10 people (90%) – you may have a rash similar to acne on your face, neck and trunk or your skin may be dry and itchy. This can be severe for some people and you may need moisturising creams, steroid creams and antibiotics. The reaction usually starts about 10 days after the start of treatment and gets better within a month of finishing treatment. You may need to have a lower dose of the drug or stop treatment for a short time
• A sore mouth and throat – your nurse or doctor can give you mouthwashes and medicines to help
• Sensitivity to sunlight – wear sun cream and cover up when you are having treatment, because sunlight can make skin reactions worse
• Nail infection
• Diarrhoea affects 3 out of 10 people (30%) – drink plenty of fluids and tell your doctor or nurse if it becomes severe or continues for more than 3 days
• Tiredness and weakness affects 1 in 2 people (50%) during and after treatment – most people find their energy levels are back to normal within 6 months to a year
• Feeling or being sick happens in about 1 out of every 5 people (20%) but is usually well controlled with anti sickness medicines
• Sore, watery, eyes (conjunctivitis) or dry, itchy eyes occur in around 1 in 5 people (20%) – very rarely this can be inflammation of the cornea and you may need to stop treatment
• Loss of appetite and weight loss
• Blurred vision – tell your doctor or nurse if you have any eye symptoms
• Abdominal pain
• Constipation – drink plenty of fluids and tell your doctor or nurse if it becomes severe or continues for more than 3 days as you can have laxatives to help
• Swollen hands and feet due to fluid build up
• Back pain
• Sleep problems
• A cough and breathlessness – let your doctor or nurse know if you have this

Between 1 and 10 in every 100 people have one or more of these.

• Headaches, dizziness or anxiety
• Dehydration in people who have severe diarrhoea – drink plenty of fluids
• Low levels of magnesium, potassium and calcium in your blood – you will have regular blood tests to check the levels of these minerals
• A cough and shortness of breath
• An allergic reaction while you have the treatment, causing a high temperature, chills, shivering (rigors), a headache, and feeling sick. A few people have a more severe reaction, with wheezing, an itchy rash, and a drop in blood pressure. Your nurse will give you medicines before treatment to try to prevent a reaction. They will stop or slow your drip if it occurs. Let your doctor or nurse know if you have fever or chills the night after the drip
• Your eyelashes may grow in a different direction to normal
• Women may stop having periods (amenorrhoea) but this may be temporary
• Loss of fertility – you may not be able to become pregnant or father a child after this treatment. Talk to your doctor before starting treatment if you plan to have a baby in the future
• An increased risk of infection due to low numbers of white blood cells – it is harder to fight infections and you can become very ill. You may have headaches, aching muscles, a cough, sore throat, pain passing urine or feel cold and shivery. Contact your treatment centre straight away if you have any of these effects
• Soreness, redness and peeling on the palms of the hands and soles of the feet (palmar–plantar syndrome), which may cause tingling, numbness, pain and dryness
• Broken nails
• Indigestion and heartburn
• Blood clot in the lung – let your doctor or nurse know straight away if you have a sudden cough or breathlessness
• Blood clot in the leg – let your doctor or nurse know straight away if you have a red, hot sore area on your leg
• Raised blood pressure

Fewer than 1 in 100 people have these.

• Inflammation and swelling of the eyelids
• Chapped lips
• Loosening of the nails
• Excessive hair growth
• A build up of fibrous tissue in the lungs (pulmonary fibrosis) – let your doctor know if you have a cough or breathlessness that starts some time after your treatment has ended

You won’t get all the side effects mentioned here and some may be very mild. A side effect may get worse through your course of treatment. Or you may have more side effects as the course goes on. This depends on

• How many times you've had a drug before
• Your general health
• How much of the drug you have (the dose)
• Other drugs you are having

Talk to your doctor, pharmacist or nurse about all your side effects so they can help you manage them. They can give you advice or reassure you. Your nurse will give you a contact number to ring if you have any questions or problems. If in doubt, call them.

Tell your doctor about any other medicines you are taking, including vitamins, herbal supplements and over the counter remedies – some drugs can react together.

Panitumumab may have a harmful effect on a baby developing in the womb. To talk to your doctor or nurse about contraception before having treatment if there is any chance that you or your partner could become pregnant. You need to use reliable contraception during treatment and for 2 months afterwards.

Breastfeeding is not advisable during this treatment because the drug may come through in the breast milk.

This page does not list all the very rare side effects of this treatment that are very unlikely to affect you. For further information look at the Electronic Medicines Compendium website at www.medicines.org.uk.

If you have a side effect not mentioned here that you think may be due to this treatment you can report it to the Medicines Health and Regulatory Authority (MHRA) at www.mhra.gov.uk.