Encorafenib and cetuximab

Encorafenib and cetuximab are types of targeted cancer drugs. Encorafenib is also known as Braftovi. Cetuximab is also known as Erbitux. You pronounce encorafenib as en-ko-raf-e-nib. And cetuximab is pronounced se-tux-i-mab.

Together they are a treatment for bowel cancer that has spread (advanced bowel cancer).

You can only have these drugs if you have both a:

• BRAF gene change (mutation) called BRAFV600E
• normal RAS gene (also called RAS wild type)

You have tests on your bowel cancer cells to check for these gene changes.

How do encorafenib and cetuximab work?

Encorafenib is a type of cancer growth blocker. It works by targeting certain proteins that help cancer cells grow. By blocking these proteins, it stops or slows down the growth of cancer cells.

Cetuximab is a type of monoclonal antibody. Monoclonal antibodies (MABs) are made in the laboratory. They seek out cancer cells by targeting particular proteins on their cell surface.

How do you have encorafenib and cetuximab?

You have cetuximab as a drip into your bloodstream. You take encorafenib as capsules.

Into your bloodstream

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

If you don't have a central line

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.

Taking your capsules

You swallow the capsules whole with a glass of water. You can take them with or without food.

You should take the right dose, not more or less.

Talk to your healthcare team before you stop taking a cancer drug or if you miss a dose.

How often do you have encorafenib and cetuximab?

You have encorafenib and cetuximab as cycles of treatment. This means that you have the drugs and then a rest to allow your body to recover. Each cycle of treatment lasts 28 days (4 weeks).

You usually take your encorafenib capsules once a day for 28 days. You have cetuximab as a drip into your bloodstream on day 1 and day 15. Cetuximab takes about 2 hours the first time you have it. If you don’t have any problems, the following treatments take around an hour.

You continue encorafenib and cetuximab for as long as they are working, 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.

You might have other tests or scans during this treatment to check for possible side effects.

What are the side effects of encorafenib and cetuximab?

Side effects can vary from person to person. They also depend on what other treatment you are having. 

When to contact your team

Your doctor, nurse, or pharmacist 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

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:

High temperature (fever)

Tell your healthcare team straightaway if you get a high temperature. Ask them if you can take paracetamol to help lower your temperature.

Fatigue

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.

Loss of appetite

You might lose your appetite for various reasons while having cancer treatment. Sickness, taste changes or tiredness can put you off food and drinks.

Difficulty sleeping (insomnia)

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.

Headaches

Tell your healthcare team if you keep getting headaches. They can give you painkillers to help.

Numbness of fingers and toes

Numbness or tingling in fingers or toes is often temporary and can improve after you finish treatment. Tell your healthcare team if you're finding it difficult to walk or complete fiddly tasks such as doing up buttons. 

Bleeding problems

You might bleed from different areas of the body. This includes vomiting or coughing up blood and passing blood in your wee (urine) or poo.

This can be serious. Contact your advice line if you have any bleeding.

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. 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.

Pain in different parts of your body

You might feel some pain from your tummy (abdomen), arms, legs, muscles, joints or back. Speak to your doctor or nurse about what painkillers you can take to help with this.

Skin problems

Skin problems can include a rash, dry skin and itching. You might develop acne or new skin growths or moles. Less commonly your skin might feel thicker, change colour, look red or peel.

In some cases, the skin on your hands and feet may get sore, blister or peel.

You are at an increased risk of developing skin cancer. This is a less common side effect. Your doctor will check your skin regularly throughout your treatment.

Let your doctor, nurse or pharmacist know if you’re worried about an area of skin at any time. They might be able to give you something to help.

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:

• an allergic reaction when you have cetuximab into your bloodstream, or at a later time. Tell your healthcare team if you have difficulty breathing, feel feverish, have chills or feel faint
• feeling dizzy
• taste changes
• a fast heartbeat
• changes to how your kidneys work, including your kidneys not working as well as before. You have regular blood tests to check this
• liver changes
• hair loss
• vision changes

Rare side effects

Fewer than 1 in 100 people (fewer than 1%) have inflammation of the pancreas (pancreatitis). You might get severe tummy pain, feel or be sick, have a high temperature or loose poo.

Other side effects

If you have side effects that aren't listed on this page, you can look at the cetuximab drug page. 

Coping with side effects

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

What else do I need to know?

Other medicines, foods and drinks

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.

Loss of fertility

It is not known whether this treatment affects fertility in people. Talk to your doctor before starting treatment if you think you may want to have a baby in the future.

If you are taking hormonal contraceptives like the pill, you should also use another barrier method such as a condom for at least a month. This is because encorafenib affects how well hormonal contraceptives work.

Breastfeeding

It is not known whether these drugs come through into the breast milk. Doctors usually advise that you don’t breastfeed during this treatment and for 6 months after your last treatment.

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 a 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.

Treatment for other conditions

If you are having tests or treatment for anything else, always mention your cancer treatment. For example, if you are visiting your dentist.

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 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.