What are encorafenib (Braftovi®) and binimetinib (Mektovi®)?

Encorafenib (Braftovi®) and binimetinib (Mektovi®) may be used in combination to treat melanoma that:

  • cannot be removed with surgery
  • has spread to other parts of the body (advanced or metastatic melanoma).

It is best to read this information with our information about melanoma. Encorafenib and binimetinib are only used if tests show that cancer cells from the tumour have a gene change called a BRAF V600 mutation. They belong to a group of targeted therapy drugs called cancer growth inhibitors.

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

How encorafenib and binimetinib are given

Encorafenib comes in capsules that you take once a day. Binimetinib comes in tablets that you take twice a day, 12 hours apart.

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 and during treatment you will have some tests, including:

  • blood tests – to check the levels of blood cells and how your liver and kidneys are working
  • heart tests, such as an ECG or echocardiogram – to check how your heart is working. 

At your appointments, the doctor, nurse or pharmacist will talk to you about your test results and ask you how you have been feeling. Sometimes they will change the dose or stop your treatment for a time to let your body recover from side effects.

Taking encorafenib and binimetinib

The nurse or pharmacist will give you the capsules and tablets to take home. You may be given capsules of different strengths. Always take them exactly as explained. This is important to make sure they work as well as possible for you. 

Your nurse or pharmacist may also give you anti-sickness drugs and other medicines to take home. Take all your capsules or tablets exactly as they have been explained to you.

You can take encorafenib and binimetinib with or without food. Take them at the same times every day. Swallow them whole with a glass of water. Do not chew, break or crush them. You should avoid eating grapefruit or drinking grapefruit juice. Grapefruit may affect how encorafenib works. 

If you forget to take encorafenib: 

  • you should take it when you remember – if it is more than 12 hours until your next dose
  • you should wait and take the next dose at the usual time – if it is less than 12 hours until your next dose
  • you should not take a double dose.

If you forget to take binimetinib: 

  • you should take it when you remember – if it is more than 6 hours until your next dose
  • you should wait and take the next dose at the usual time – if it is less than 6 hours until your next dose 
  • you should not take a double dose.

Other things to remember about your capsules and tablets:

  • Keep them in the original package.
  • Keep them safe and out of sight and reach of children.
  • If you are sick after taking the capsules or tablets, contact the hospital. Take the next dose at the usual time. Do not take a double dose. 

If your treatment is stopped, return any unused capsules and tablets to the pharmacist.

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. 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.

Common side effects

Feeling sick

You may feel sick during 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 often and eat small amounts regularly. It is important to drink enough fluids. If you continue to feel sick, or are sick (vomit) more than once in 24 hours, contact the hospital as soon as possible. They will give you advice. Your doctor or nurse may change the anti-sickness drug to one that works better for you.

Diarrhoea

This treatment may cause severe 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.

Your hospital team may give you anti-diarrhoea drugs to take at home.

If you have diarrhoea or a mild increase in stoma activity:

  • follow any advice from your cancer team about taking anti-diarrhoea drugs
  • drink at least 2 litres (31/2 pints) of fluids each day.

Contact the hospital straight away if:

  • you have diarrhoea at night
  • you have diarrhoea more than 4 times in a day 
  • you have a moderate or severe increase in stoma activity 
  • the anti-diarrhoea drugs do not work within 24 hours.

You may need to go to hospital to have fluids through a drip.

Constipation

This treatment can cause constipation. Constipation means that you are not able to pass stools (poo) as often as you normally do. It can become difficult or painful. 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.

Tummy pain

This treatment can cause pain in your tummy (abdomen). Tell your doctor or nurse if this happens 

They can give you advice and treatment if needed. If you get severe pain in your tummy contact your doctor straight away.

Feeling tired

Feeling tired is a common side effect of this treatment. 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 use machinery.

Effects on the eyes

This treatment can affect your eyes. Always tell your doctor or nurse if you have sore eyes, blurry vision or any sight loss. They may give you eye drops or other treatments to help. They may also arrange a specialist eye check for you. Do not drive if your eyesight is affected.

Muscle or joint pain

This treatment can cause pain in your muscles or joints. If this happens, tell your doctor so they can give you painkillers. Tell them if the pain does not get better. 

Sometimes this treatment can cause a muscle condition called rhabdomyolysis. Symptoms may include: 

  • muscle pain
  • weakness 
  • dark-red or brown urine (pee).  

This condition is not common and does not always cause symptoms. You will have regular blood tests to check for signs of it. Your doctor may change the dose or stop your treatment for a time to let your body recover from this side effect.

Effects on the kidneys and liver

This treatment can affect how your kidneys and liver work. This is usually mild and goes back to normal after treatment. You will have blood tests to check how well your kidneys and liver is working.

It is important to drink at least 2 litres (3½ pints) of fluids each day to help protect your kidneys

Blood pressure

This treatment can cause high blood pressure. Your doctor or nurse will check your blood pressure regularly during treatment. If needed they will give you medicines to control your blood pressure.

Bleeding

This treatment may increase your risk of bleeding. Tell your doctor if you have any bruising or bleeding that you cannot explain. This includes:

  • blood in your pee 
  • blood in your poo, or black poo
  • bleeding from the rectum (back passage)
  • vomiting up blood
  • vomit that looks like coffee grounds.

Anaemia (low number of red blood cells)

This treatment can reduce the number of red blood cells in your blood. Red blood cells carry oxygen around the body. If the number of red blood cells is low, this is called anaemia. You may have symptoms such as:

  • pale skin
  • lack of energy
  • feeling breathless
  • feeling dizzy and light-headed.

Tell your doctor or nurse if you have these symptoms.

If you are very anaemic, you may need a drip to give you extra red blood cells. This is called a blood transfusion.

Headaches

This treatment may cause headaches. If you have headaches, tell your doctor. They may give you painkillers to help.

Skin changes

This treatment may cause a rash or itchy skin. Or you may notice some areas of skin become thicker than usual. Your skin in some areas may become darker. Less commonly, the skin may peel or you may get small acne-like bumps.

Your skin may become more sensitive to light than usual. If your skin feels dry, try using an unperfumed moisturising cream every day.

These changes are usually temporary and improve after treatment finishes. Always tell your doctor or nurse straight away about any skin changes. They can check your skin and give you advice. They may arrange further tests or give you creams or medicines to help.

Sore and red palms of hands and soles of feet

You may get sore and red palms of hands and soles of feet. The skin may also begin to peel. This is called palmar-plantar or hand-foot syndrome. It usually gets better after treatment ends.

Tell your doctor or nurse about any changes to your hands or feet. They can give you advice and prescribe creams to improve any symptoms you have. It can help to:

  • keep your hands and feet cool
  • moisturise your hands and feet regularly
  • avoid tight-fitting socks, shoes and gloves.

Hair loss

Your hair may get thinner or you may lose all the hair from your head. Hair loss is almost always temporary. Your hair will usually grow back after treatment ends. Your nurse can talk to you about ways to cope with hair loss.

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.

Numb or tingling hands or feet (peripheral neuropathy)

This treatment may affect the nerves, which can cause numb, tingling or painful hands or feet. You may find it hard to fasten buttons or do other fiddly tasks.

Tell your doctor if you have these symptoms. They sometimes need to lower the dose of the drug. The symptoms usually improve slowly after treatment finishes. But for some people they may never go away. Talk to your doctor if you are worried about this.

Dizzinesss

This treatment can make you feel dizzy. This is usually mild. Tell your doctor or nurse if you feel dizzy or faint. If you feel dizzy or faint, do not drive or operate machinery.

Less common side effects

Allergic reaction

Some people have an allergic reaction while having this treatment. 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 mouth
  • pain in your back, tummy or chest. 

If you feel unwell or have any of these signs, contact the hospital straight away.

Changes to your taste

You may get a bitter or metal taste in your mouth. Sucking sugar-free sweets may help with this. Some foods may taste different or have no taste. Try different foods to find out what tastes best to you. Taste changes usually get better after treatment finishes. Your nurse can give you more advice.

Effects on the heart

This treatment can affect how the heart works. You may have tests to see how well your heart is working. These may be done before, during and after treatment.

If the treatment is causing heart problems, your doctor may change the type of treatment you are having.

Contact your doctor straight away on the 24-hour number the hospital has given you if you have any of these symptoms during or after treatment:
  • pain or tightness in your chest
  • breathlessness
  • dizziness
  • changes to your heartbeat.

Other conditions can cause these symptoms, but it is important to get them checked by a doctor. If you cannot get through to your doctor, call the NHS urgent advice number on 111.

Effects on the lungs

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

  • a cough
  • wheezing
  • breathlessness.

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

Blood clot risk

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

  • throbbing pain, redness or swelling in a leg or arm
  • suddenly feeling breathless or coughing
  • sharp chest pain, which may be worse when you cough or take a deep breath.

If you have any of these symptoms, contact the hospital straight away on the 24-hour contact number you have been given. If you cannot get through to your doctor, call the NHS urgent advice number on 111.

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

You can help reduce the risk of developing a blood clot by:

  • staying active during treatment
  • drinking plenty of fluids, especially water.

You may be given anticoagulants to help prevent a clot.

Other types of cancer

This treatment may increase your risk of developing some other cancers, such as squamous cell skin cancer. But treating the melanoma usually outweighs this risk. Your doctor or nurse will give you more information about this.

Other information

Other medicines

Some medicines can affect how this treatment works or be harmful when you are having it. Always tell your cancer doctor about any drugs you are taking or planning to take, such as:

  • medicines you have been prescribed
  • medicines you buy in a shop or chemist
  • vitamins, herbal drugs and complementary therapies.

Tell other doctors, pharmacists or dentists who prescribe or give you medicines that you are having this cancer treatment.

You can visit the electronic Medicines Compendium (eMC) for more detailed information about your treatment.

Vaccinations

Vaccinations can reduce your risk of getting certain infections. Your doctor or nurse may talk to you about having vaccinations.

Doctors usually recommend that people with cancer have a flu vaccination and a coronavirus (covid) vaccination. These are both inactivated vaccinations that can help reduce the risk of infection. People with weak immune systems can have these, as they are not live vaccinations. 

If your immune system is weak, you need to avoid live vaccinations. This is because they can make you unwell. Live vaccines contain a very weak version of the illness they are vaccinating you against. Your cancer doctor or GP can tell you more about live and inactivated vaccinations.

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

You are advised not to breastfeed while having this treatment, or for some time after treatment finishes. This is because the drugs could be passed to the baby through breast milk.

Your doctor or nurse can give you more information.

Lactose

Binimetinib tablets contain lactose. Tell your doctor if you have a lactose intolerance.

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.

Medical and dental treatment

If you need medical treatment for any reason other than cancer, always tell the doctors and nurses 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.

About our information

  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert health professionals and people living with cancer.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

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