Dostarlimab (Jemperli®)

Dostarlimab (Jemperli®) is an immunotherapy drug. It may also be called a checkpoint inhibitor. It is best to read this information with our general information about immunotherapy drugs and the type of cancer you have.

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

This information is correct at time of publishing. But sometimes the types of cancer this treatment is used for, or treatment side effects, may change between revision dates.

You can talk to your cancer team if you want more detailed information about this treatment. Or visit the electronic Medicines Compendium (eMC) website, which has patient information leaflets (PIL) for individual drugs.

We explain the most common side effects of this treatment here. We also include some that are less common. This treatment can make the immune system too active. This can cause side effects that may be serious if not treated quickly.

You may get some of the side effects we mention, but you are unlikely to get all of them. And you may have some side effects, including rarer ones, that we have not listed here.

Other cancer treatments may cause different side effects. If you are also having other cancer treatment, you may have other side effects.

Do not try to treat side effects yourself. Always tell your doctor, nurse or pharmacist about any side effects you have. They can give you:

• drugs to help control some side effects 
• advice about managing side effects. 

It is important to take any drugs exactly as explained. This means they will be more likely to work for you.

Some cancer treatments can cause serious side effects. Sometimes, these may be life-threatening. Your doctor, nurse or pharmacist can explain the risk of these side effects to you.

This treatment may also cause delayed side effects. These can start weeks, months, or sometimes more than a year after you finish treatment.

If you have symptoms or side effects that start during treatment or after treatment ends, contact the hospital straight away on the 24-hour number. Side effects can become serious if they are not treated.

They will also give you a card with information about your treatment. It is important to keep the card with you during treatment and after treatment ends. You should show it to any doctor or healthcare professional caring for you.

Your doctor, nurse or pharmacist will give you 24-hour contact numbers for the hospital. If you feel unwell or need advice, you can call at any time of the day or night. Save these numbers in your phone or keep them somewhere safe.

This treatment can make the immune system too active. This can cause the following side effects. Some of them are rare. But it is important to know about them.

Do not try to treat these side effects yourself. If you have these side effects during treatment or after it ends, always contact the hospital straight away on the 24-hour number.

This treatment may cause inflammation in the skin. This is usually mild, but can if it is not treated it can become serious. You may need creams, steroids or other medicines to treat skin problems. If you notice skin changes during treatment, or after treatment ends, contact the hospital on the 24-hour number as soon as possible. Skin changes can include: 

• a rash or bumps on the skin
• dry or itchy skin
• patches of white or paler skin.

To protect your skin from the sun, use suncream with of at least SPF 30. SPF stands for sun protection factor. Cover up with clothing and a hat. 

Contact the hospital straight away on the 24-hour number if you have any of these symptoms:

• a rash that is spreading
• blistering or peeling skin
• flu-like symptoms, such as a high temperature and joint pain. 

These symptoms can be a sign of a serious skin reaction that needs to be treated immediately in hospital.

You may have diarrhoea or tummy (abdominal) pain. This treatment can also cause inflammation of the bowel (colitis) which can be very serious. 

Diarrhoea means passing more stools (poo) than is normal for you, or having watery or loose stools. If you have a stoma, it may be more active than usual.

Contact the hospital straight away on the 24-hour number if you have any of the following symptoms during treatment, or after treatment ends:

• You have diarrhoea 4 or more times in a day. 
• You have a moderate increase in stoma activity. 
• You have uncomfortable tummy cramps. 
• You have diarrhoea at night. 
• Your temperature is over 37.5°C.
• There is blood or mucus in your stool.

You may need to go into hospital to have fluids through a drip or treatments such as steroids.

This treatment can cause sore or weak muscles. Your joints may also be stiff, sore or swollen (arthritis). If you already have problems with joint pain, this may become worse. Contact the hospital on the 24-hour number if you have any of these symptoms during treatment or after it ends:

• new or worsening aches or pains
• new or worsening stiffness in a joint
• swollen joints.

You may need steroids or other treatments, such as painkillers.

This treatment may affect your hormones. Hormones control many different processes in the body. You will have regular blood tests to check some of your hormone levels. Contact the hospital on the 24-hour number if you have any of these side effects during treatment or after it ends:

• increased sweating
• weight gain or weight loss
• dizziness or fainting
• feeling more hungry or thirsty than usual
• loss of sex drive
• passing urine (peeing) more often than usual
• headaches that do not go away
• feeling more tired than usual (fatigue)
• mood changes.

You may need drugs to control your hormone levels.

This treatment can cause inflammation of the lungs. This is called pneumonitis. Contact the hospital straight away on the 24-hour number if you notice any of these changes during treatment or after it ends:

• breathlessness
• a cough that does not go away
• wheezing
• a fever, with a temperature over 37.5°C.

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

This treatment can cause liver inflammation and may affect how your liver works. This is called hepatitis. You will have regular blood tests to check this. If the blood tests show liver changes, you may have steroids.

Sometimes liver changes can be serious. Contact the hospital straight away on the 24-hour number if you have any of these symptoms during treatment or after it finishes:

• yellow skin or eyes
• feeling very sleepy
• dark urine (pee)
• unexplained bleeding or bruising
• pain in the right side of your tummy (abdomen)
• loss of appetite.

This treatment can cause kidney inflammation and may affect how the kidneys work. This is called nephritis. This is not common, but if it is not treated it can become serious. You will have regular blood tests to check how your kidneys are working. If tests show kidney changes, you may have steroids or other treatments.

Contact the hospital straight away on the 24-hour number during treatment, or after it ends, if you either:

• have blood in your urine (pee) 
• are passing less urine or peeing less often than usual.

This treatment can affect your eyes and eyesight. Contact the hospital straight away on the 24-hour number if you have any of these symptoms during treatment or after it ends:

• sore, painful, or swollen eyes
• eyes that are sensitive to light
• changes to your eyesight.

You may need steroids or other treatments. A specialist eye doctor (ophthalmologist) may also need to check your eyes.

Rarely, this treatment can affect the brain and nerves. These effects may be mild at first, but can become serious if they are not treated. Contact the hospital straight away on the 24-hour number if you have any of these symptoms during treatment or after it ends:

• any weakness, numbness or tingling in your arms, legs or face
• a headache that does not get better
• dizziness
• drowsiness or confusion
• problems with moving or speaking
• any unexplained pain in other parts of your body.

You may need steroids and other treatments.

This treatment can affect how the heart works. This is not common, but it can be serious. You may have tests to check how well your heart is working. These may be done before, during and after treatment.

Contact the hospital straight away on the 24-hour number if you have any of these symptoms during or after treatment:

• breathlessness
• dizziness
• changes to your heartbeat (palpitations)
• swollen feet and ankles.

Other conditions can cause these symptoms, but it is important to get them checked by a doctor. 

Always call 999 if you have:

• chest pain, pressure, heaviness, tightness or squeezing across the chest
• difficulty breathing.

If your symptoms are caused by this treatment, you may need steroids. You may be monitored in hospital for a time.

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 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.

Doctors usually recommend that people with cancer have vaccinations for flu and for coronavirus (covid). These help reduce your risk of serious illness from these infections. Most people can have these vaccines, including people with weak immune systems.

If your immune system is weak, you should not have live vaccinations. Live vaccines can make you unwell because they contain a very weak version of the illness they will protect you against. Live vaccines include Zostavax^®, which is a shingles vaccine, and 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.

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.

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.

If you need medical treatment for any reason other than cancer, always tell the healthcare professional that you are having cancer treatment. Show them your patient alert card. 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 or optician, always tell them you are having cancer treatment. Talk to your cancer team before you have any dental treatment.