Tebentafusp (Kimmtrak®)

You have tebentafusp as a drip into a vein (intravenous infusion) once a week. The infusion takes 15 to 20 minutes.

After each of the first 3 infusions, you will need to stay in hospital overnight. After this, you may be able to have the infusions in a day unit or clinic as an outpatient.

During a course of treatment, you will meet someone from your cancer team, such as a:

• cancer doctor
• specialist nurse
• specialist pharmacist.

This is who we mean when we mention doctor, nurse or pharmacist in this information.

During your course of treatment, you will have regular blood tests. This is to check that it is safe for you to have treatment.

You will meet with a doctor, nurse or pharmacist before you have treatment. They will talk to you about your blood results and ask how you have been feeling. If your blood results are okay, the pharmacy team will prepare your targeted therapy.

You have tebentafusp infusions through 1 of the following:

• a cannula – a short, thin tube the nurse puts into a vein in your arm or hand
• a central line – a fine tube that goes under the skin of your chest and into a vein close by
• a PICC line – a fine tube that is put into a vein in your arm and goes up into a vein in your chest
• an implantable port (portacath) – a disc that is put under the skin on your chest or arm and goes into a vein in your chest.

You usually have tebentafusp once a week. You keep having it as long as it is effective and any side effects are manageable.

Your cancer team will discuss your treatment plan with you.

Your cancer team may also give you other medicines and creams to take home. Take these exactly as they tell you to.

This treatment makes the body release large amounts of cytokines. Cytokines are chemical messengers that help your immune system protect the body from infection and illness.

You may have flu-like symptoms. These can range from mild to severe. You may need treatment and close monitoring until the symptoms improve. Some people will be monitored and treated in intensive care.

CRS is most likely to happen the first few times you have this treatment. But it can happen later. If you have any of the following symptoms at any time during this treatment, contact the hospital straight away on the 24-hour number:

• a high temperature
• chills
• a fast heart rate
• dizziness or light-headedness
• a headache
• muscle or joint pain
• diarrhoea
• feeling sick or being sick (vomiting)
• difficulty breathing or shortness of breath.

This treatment can cause a skin reaction. This is usually mild but may need treatment. Your cancer team will give you cream and medicines to take at home if you have a reaction. Always follow their advice.

Skin reactions are most likely to happen after the first 3 infusions of tebentafusp. Tell your nurse straight away if you have any of the following side effects:

• a rash
• itchy skin
• swelling or puffiness of the body or the skin around the eyes.

If side effects happen when you are at home, contact the hospital straight away on the 24-hour number for advice.

You may feel sick during this treatment, but this is usually mild. Your doctor, nurse or pharmacist may prescribe you anti-sickness drugs to help prevent or control sickness. Take the drugs exactly as they tell you to. If you feel sick, take small sips of fluid often and eat small amounts regularly. It is important to drink enough fluids.

If you continue to feel sick, or if you are sick (vomit) 1 to 2 times in 24 hours, contact the hospital on the 24-hour number as soon as possible. They will give you advice.

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

If you are passing loose stools 3 or more times a day and this is not normal for you, contact the hospital as soon as possible on the 24-hour number. Follow the advice they give you about:

• taking anti-diarrhoea medicines 
• drinking enough fluids to keep you hydrated and to replace lost salts and minerals
• any changes to your diet that might help. 

They might also ask you for a specimen of your stool to check for infection.

You may get pain in your tummy (abdomen), or have indigestion. Your doctor, nurse or pharmacist can give you advice or treatment to help. Contact the hospital straight away on the 24-hour number if your symptoms do not go away, or get worse.

This treatment can affect your appetite. Don’t worry if you do not eat much for 1 or 2 days. But if your appetite does not come back after a few days, or if you are losing weight, tell your doctor, nurse or pharmacist. They can give you advice. They may give you food or drink supplements. Or they may suggest changes to your diet or eating habits to help.

Feeling tired is a common side effect of this treatment. Try to pace yourself and plan your day so you have time to rest. Gentle exercise, like short walks, can help you feel less tired.

If you feel sleepy, do not drive or use machinery.

You may get pain in your muscles or joints for a few days after treatment. If this happens, tell your doctor, nurse or pharmacist. They can give you painkillers and advice. They can also tell you if any of the painkillers you usually take are suitable. 

Tell them if the pain does not get better. Having warm baths and resting regularly may help. 

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

This treatment may cause numbness or tingling. Tell your doctor, nurse or pharmacist if you have these symptoms.

This treatment can increase or decrease your blood pressure. A nurse will check your blood pressure regularly during your treatment. If you have headaches, nosebleeds, changes to your eyesight, shortness of breath or feel dizzy, let your doctor, nurse or pharmacist know.

Cancer and some cancer treatments can increase the risk of a blood clot. Contact the hospital straight away on the 24-hour number if you have any of these symptoms during or after treatment:

• throbbing pain or swelling in a leg or arm
• reddening of the skin in the area – if you have black or brown skin, this can be harder to notice, but the skin might become darker
• suddenly feeling breathless or coughing.

Always call 999 if you have:

• chest pain
• difficulty breathing.

A blood clot is serious, but it can be treated with drugs called anticoagulants. These thin the blood. Your doctor, nurse or pharmacist can give you more information about preventing and treating blood clots.

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

• medicines you have been prescribed
• medicines you buy in a shop, pharmacy or online
• vitamins or supplements 
• herbal drugs and complementary or homeopathic therapies
• recreational drugs – for example, cannabis.

Cancer doctors usually recommend that people with cancer have vaccinations for flu and coronavirus (covid). They may also recommend other vaccines, such as Shingrix^® for shingles. These all help reduce your risk of serious illness from these infections. Most people can have these vaccines, including people with weak immune systems.

You should not have live vaccines if your immune system is weak. This includes if you are having or recently had chemotherapy, radiotherapy or other cancer treatments that affect your immune system. Live vaccines can make you unwell because they contain a very weak version of the illness they protect you against. There are several live vaccines, including the yellow fever vaccine.

It is important to ask your doctor, nurse or pharmacist for advice about having vaccinations. They can explain what vaccines are right for you and when it is best to have them.

Your doctor, nurse or pharmacist will advise you not to get pregnant or make someone pregnant while having this treatment and for some time afterwards. The drugs may harm a developing baby. It is important to use contraception to prevent pregnancy. Follow their advice about:

• what types of contraception to use 
• how long after treatment you should continue to use contraception. 

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

Your doctor, nurse or pharmacist can give you more information.

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.

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

If you have appointments with a dentist, always tell them you are having cancer treatment. Talk to your cancer team before you have any dental treatment.