Dostarlimab (Jemperli)

Dostarlimab is a type of immunotherapy. It is also known as Jemperli.

You pronounce dostarlimab as dos-tar-lih-mab. 

It is a treatment for womb cancer that has spread or come back (advanced or recurrent womb cancer). 

To have this treatment, the cancer must have gene changes called:

  • mismatch repair deficient Open a glossary item (dMMR)  
  • microsatellite instability-high Open a glossary item (MSI-H) 

Your doctor can you tell you if your cancer has these changes. 

How does dostarlimab work?

Dostarlimab is a type of monoclonal antibody that stimulates the immune system to destroy cancer cells. It works by attaching to a protein called PD-1 on the surface of cancer cells. This helps the immune system to recognise and attack the cancer.

How do you have dostarlimab?

You have dostarlimab as a drip into your bloodstream. It takes about 30 minutes.

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.

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

How often do you have dostarlimab?

You have dostarlimab as cycles of treatment. This means that you have the drug and then a rest to allow your body to recover. 

You have dostarlimab once every 3 weeks for the first 4 cycles. 

Then the dose is increased, and you have dostarlimab once every 6 weeks. 

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


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.

Patient card

Your healthcare team will give you a small card to carry with you. This explains the side effects you should look out for and what to do if you have them. You should keep this with you throughout your treatment and for a few months afterwards. It is important to show the card to anyone else treating you, such as your dentist or in an emergency. This is so that they know what treatment you are on.

What are the side effects of dostarlimab?

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

This treatment affects the immune system. This may cause inflammation in different parts of the body which can cause serious side effects. They could happen during treatment, or some months after treatment has finished. In some people, these side effects could be life threatening.

When to contact your team

Your doctor 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

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:

Breathlessness and looking pale

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

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.

Skin problems 

Skin problems include a skin rash, dry skin and itching. This usually goes back to normal when your treatment finishes. Your healthcare team can tell you what products you can use on your skin to help.


Contact your advice line if you have diarrhoea, such as if you've had 4 or more loose watery poos (stools) in 24 hours. Or if you can't drink to replace the lost fluid. Or if it carries on for more than 3 days.

Your doctor may give you anti diarrhoea medicine to take home with you after treatment. Eat less fibre, avoid raw fruits, fruit juice, cereals and vegetables, and drink plenty to replace the fluid lost.

Joint pain 

You might have pain in your joints. Speak to your doctor or nurse about what painkillers you can take to help with this.

Less commonly, you might have muscle pain.

Low levels of thyroid hormones 

The levels of your thyroid hormones may change. You may feel tired or cold, gain weight, feel sad or depressed, or your voice may deepen. You will have regular blood tests to check your thyroid hormone levels.

Changes to your liver 

You might have liver changes that are usually mild and unlikely to cause symptoms. They usually go back to normal when treatment finishes. You have regular blood tests to check for any changes in the way your liver is working.

High temperature

If you get a high temperature, let your healthcare team know straight away. Ask them if you can take paracetamol to help lower your temperature.

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:

  • high levels of thyroid hormone (hyperthyroidism) – you might feel shaky, have a fast heartbeat or weight loss

  • inflammation of the lungs –symptoms include shortness of breath, cough and tiredness

  • feeling cold or shivery (chills)

  • inflammation of the bowel (colitis) or stomach (gastritis)

  • inflammation of the pancreas (pancreatitis)

  • inflammation of the liver (hepatitis)

  • lower levels of hormones from the adrenal glands

  • an allergic reaction that can cause a rash, shortness of breath, redness or swelling of the face and dizziness - some allergic reactions can be life threatening, alert your nurse or doctor if you notice any of these symptoms

Rare side effects

These side effects happen in fewer than 1 in 100 people (less than 1%). You might have one or more of them. They include:

  • inflammation of the pituitary gland in the base of the brain- symptoms include tiredness, headache, sickness, low blood pressure and changes in vision
  • inflammation of the eye - symptoms include vision changes and eye pain
  • type 1 diabetes
  • a complication of diabetes called diabetic ketoacidosis. This happens when the body is lacking insulin, causing substances called ketones to build up in the blood. Symptoms include breathing deeply, breath that smells fruity (like nail polish remover), feeling tired, sleepy or confused. This condition can be life threatening and you will need urgent treatment in hospital
  • inflammation of the brain. Symptoms include a high temperature, a headache, confusion, drowsiness and seizures. Contact your advice line if you have any of these symptoms
  • inflammation in other parts of the body including the kidneys, food pipe (oesophagus), thyroid and bones

Coping with side effects

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

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.

Pregnancy and contraception

This drug may harm a baby developing in the womb. It is important not to become pregnant while you are having treatment and for a few months afterwards.

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


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.


It is not known whether this drug comes through into the breast milk. Doctors advise that you don’t breastfeed during this treatment and for at least 4 months afterwards.

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.


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 Open a glossary item 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.

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