Teclistamab (Tecvayli)

Teclistamab is a type of ​targeted cancer drug​. You pronounce it as tek-lis-ta-mab. It is also known as Tecvayli.

It is a treatment for myeloma. You might have teclistamab if you have had at least 3 other kinds of treatment that have not worked or have stopped working.

Find out about myeloma

How often do you have teclistamab?

You have a low dose of teclistamab to begin with. This is to help reduce the risk of certain side effects. Teclistamab can cause a side effect called cytokine release syndrome or CRS. It can also affect the brain and nervous system, causing a side effect known as ICANS. You can read about this in the side effects section.

You also have other medicines before your first 3 injections. These help to prevent or reduce any reaction.

You usually stay in hospital for the first 3 doses of teclistamab. This is so the team looking after you can check for side effects. After that you have the rest of your treatment in a day unit or outpatient clinic. 

You should not drive from the start of treatment (your first dose) up until 48 hours after your third dose.

Exactly how you have teclistamab depends on your situation. The following is an example:

Day 1

• You have a low dose of teclistamab for your first injection (step up dose 1)

Day 3

• You have a higher dose of teclistamab (step up dose 2)

Day 5

• You have the full dose of teclistamab (1st maintenance dose)

You then continue to have teclistamab once a week. This is called ​maintenance treatment​ . 

You usually have teclistamab for as long as it is working and the side effects aren’t too bad.

If teclistamab is working well for you after 6 months, your doctor might suggest you have it every 2 weeks.

What are the side effects of teclistamab?

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, pharmacist or nurse 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

Early treatment can help manage side effects better. 

We haven't listed all the side effects here. Talk to your healthcare team if you have any new symptoms that you think might be a side effect of your treatment.

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:

Cytokine Release Syndrome (CRS)

Cytokines are group of proteins in the body that play an important part in boosting the immune system. Teclistamab stimulates the immune system to make large amounts of cytokines. This can cause a severe immune reaction. Some of the symptoms include fever, chills, nausea, fast heartbeat, headache, difficulty breathing, low blood pressure and dizziness. Let your medical team know straight away if you have any of these symptoms. You can have treatment to reverse the syndrome.

Increased risk of infection

Increased risk of getting an infection is due to a drop in white blood cells. Symptoms include a change in temperature, aching muscles, cough, headaches, feeling cold and shivery, pain or a burning feeling when peeing, or generally feeling unwell. You might have other symptoms depending on where the infection is.

Infections can sometimes be life threatening. You should contact your advice line urgently if you think you have an infection.

Bruising, bleeding gums or nosebleeds

This is due to a drop in the number of platelets in your blood. These blood cells help the blood to clot when we cut ourselves. You may have nosebleeds or bleeding gums after brushing your teeth. Or you may have lots of tiny red spots or bruises on your arms or legs. This is known as petechiae.

Breathlessness and looking pale

You might be breathless and look pale due to a drop in red blood cells. This is called anaemia.

Pain

You may have pain in your bones, muscles or joints. This can include in your ears, groin, chest, teeth and jaw. You might have muscle cramps or twitching (spasms). Let your doctor know if you are having pain. They can give you medicine to help.

Tiredness and weakness (fatigue)

You might feel very tired and as though you lack energy.

Various things can help you to reduce tiredness and cope with it, for example exercise. Some research has shown that taking gentle exercise can give you more energy. It is important to balance exercise with resting.

Pain and inflammation at the injection site

You may get some redness, swelling or pain at the injection site. Tell your nurse if you notice any of these symptoms.

Diarrhoea

Contact your advice line if you have diarrhoea. For example, in one day you have 2 or more loose bowel movements than usual. If you have a stoma, you might have more output than normal. Your doctor may give you anti diarrhoea medicine to take home with you after treatment.

Try to eat small meals and snacks regularly. It’s best to try to have a healthy balanced diet if you can. You don’t necessarily need to stop eating foods that contain fibre. But if your diet is normally very high in fibre, it might help to cut back on high fibre foods such as beans, nuts, seeds, dried fruit, bran and raw vegetables.

Drink plenty to try and replace the fluid lost. Aim for 8 to 10 glasses per day.

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.

Headaches

Let your doctor or nurse know if you have headaches. They will try to find out the cause.

Constipation

Constipation is easier to sort out if you treat it early. Drink plenty and eat as much fresh fruit and vegetables as you can. Try to take gentle exercise, such as walking. Tell your healthcare team if you think you are constipated. They can give you a laxative if needed.

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.

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.

Fluid build up in your hands and legs

You may have swelling of your hands, face and legs due to a build up of fluid (oedema).

Changes in blood pressure

During treatment, your blood pressure may be lower or higher than normal. Tell your nurse if you feel dizzy or faint. Or if you have headaches, nosebleeds, blurred or double vision, or shortness of breath. Your nurse will check your blood pressure while you are having treatment.

Changes in levels of minerals in your blood

You might have changes to the way your liver and kidneys are working. You may have changes in levels of minerals and salts in your blood, such as low potassium, magnesium and phosphate. Or a high calcium level.

You have regular blood tests during treatment to check this.

Lung problems

You might develop a cough or breathing problems. This could be due to infection, such as pneumonia or inflammation of the lungs (pneumonitis).

Tummy (abdominal) pain

Contact your advice line if you have this. Depending on what is causing the pain, they might give you medicine 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:

• a serious reaction to an infection (sepsis) - signs can include feeling very unwell, not passing urine, being sick, muscle pain, a very high or very low temperature, shivering, breathlessness, mottled or discoloured skin. Call 999 or go to accident and emergency (A&E) immediately if you have any of these symptoms

• brain changes - sometimes this treatment can cause problems to the brain (neurotoxicity). This is known as immune effector cell associated neurotoxicity syndrome (ICANS). Symptoms can be mild or severe and include shaking, confusion, fever, difficulty breathing, dizziness, headaches, fits, drowsiness, or changes to your speech. Tell your doctor or call 999 straight away if you notice this

• low calcium levels in your blood causing symptoms such as painful muscle spasms and cramps, twitching of muscles, numbness or tingling in feet and hands or around the mouth

• changes to the way your blood clots

• low blood sugar levels

• skin infection causing redness and swelling (cellulitis)

• low oxygen levels in the blood (hypoxia)

What else do you need to know?

Other medicines, food and drink

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.

Contraception and pregnancy

This treatment might harm a baby developing in the womb. It is important not to become pregnant or get someone pregnant while you're having treatment.

Women must not become pregnant for at least 5 months after the end of treatment. Men should not get someone pregnant for at least 3 months after treatment.

Talk to your doctor or nurse about effective contraception before starting treatment. Let them know straight away if you or your partner become pregnant.

Breastfeeding

Don’t breastfeed during this treatment and for 5 months afterwards. The drug may come through in the breast milk.

You and your doctor will decide if the benefit of breastfeeding is greater than the risk to your baby. If you and your doctor decide to stop taking this medicine, you should not breastfeed for 5 months after stopping 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

You should not have live vaccines from 4 weeks before treatment starts. 

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, and yellow fever.

You can usually 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 a vaccine in relation to your cancer treatment.

Contact with others who have had immunisations 

You can be in contact with other people who have had live vaccines as injections. If someone has had a live vaccine by mouth or nasal spray there may be a small risk the vaccine virus can be passed onto you if your ​immune system​ is weakened.

Your healthcare team will let you know if you need to take any precautions if you are in close contact with someone who has had a live vaccine.

Read more about immunisations and cancer treatment