Mifamurtide (Mepact)

Mifamurtide is a type of targeted cancer drug, pronounced mee-fam-ure-tide. It is also known as Mepact.

It is a treatment for osteosarcoma.

It is for children and young people aged between 2 and 30 years. You have it with chemotherapy after surgery to help lower the risk of the cancer coming back.

How does mifamurtide work?

Mifamurtide is a targeted cancer drug. It boosts the immune system to kill cancer cells. It makes the immune system produce certain types of white blood cells called monocytes and macrophages.

How do you have mifamurtide?

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

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.

How often do you have mifamurtide?

You have mifamurtide as a drip into your bloodstream over 1 hour. You have a total of 48 doses of mifamurtide. This makes 36 weeks in total (about 9 months).

For the first 12 weeks you have mifamurtide twice a week, at least 3 days apart.

Then you have it once a week for another 24 weeks.


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.

What are the side effects of mifamurtide?

Side effects can vary from person to person. They also depend on what other treatments you're having. 

When to contact your team

Your doctor, nurse or pharmacist will go through the possible side effects. They will monitor you 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. 

Contact your advice line immediately if you have signs of infection, including a temperature above 37.5C or below 36C.

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.

Tiredness and weakness (fatigue)

Tiredness and weakness (fatigue) can happen during and after treatment. Doing gentle exercises each day can keep your energy up. Don't push yourself, rest when you start to feel tired and ask others for help.

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.

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.


Tell your doctor or nurse if you keep getting headaches. They can give you painkillers to help.


This drug might make you feel dizzy. Don’t drive or operate machinery if you have this.


You might sweat more than usual. Talk to your doctor if this becomes a problem for you.

Heart problems

You might have a fast heartbeat. Tell your healthcare team if you have any of these symptoms.

Changes in blood pressure

During treatment, your blood pressure may be lower or higher than normal. Tell your nurse if you feel dizzy, faint, or if you have headaches, nosebleeds, blurred or double vision, or shortness of breath. Your blood pressure usually goes back to normal while you are on treatment or when treatment ends.

Cough, fast breathing and breathlessness

It is important to tell your doctor or nurse if you have a cough, feel breathless or find you are breathing fast. Or less commonly if you have a wheeze.

This could be due to an infection in your chest or a build-up of fluid in the lung (pleural effusion), but this is not as common.

The doctors and nurses can get you medicine to help and work out the cause.

High temperature (fever)

You might get a high temperature (fever) for a few hours after mifamurtide.

If a fever continues for more than 8 hours after you’ve had mifamurtide then contact your doctor immediately.


You might shake or shiver. Let your doctor or nurse know if this continues for more than 8 hours after you’ve had mifamurtide.


Constipation Open a glossary item is easier to sort out if you treat it early. Drink plenty of fluids 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 prescribe a laxative.


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.

Pain in different parts of the body

You might have pain from taking this drug. Talk to the team looking after you about this. 

This more commonly includes aches and pain in muscles, joint stiffness, pain in hand or foot, back and chest pain.

You may occasionally have pain in other areas of the body such as the liver, neck, groin, bone, shoulder and from where the cancer it. Mifamurtide can also cause catheter site pain and pain after the drug is given.


Hypothermia is when there is a dangerous drop in body temperature. You may start shivering, become pale, have slurred speech and feel confused. Contact your doctor straight away if this happens.

Feeling generally unwell

Speak to your doctor or nurse if you feel generally unwell after taking this drug.

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:

  • bruising, bleeding gums, or nosebleeds due to a drop in the level of platelets in your body

  • confusion

  • sleeping problems including difficulty sleeping (insomnia), drowsiness or sleepiness

  • depression and anxiety

  • blurred vision

  • ear problems including hearing loss and ringing in the ears (tinnitus)

  • a feeling as though everything around you is spinning which can affect your balance (vertigo)

  • indigestion symptoms include heartburn, bloating and burping

  • skin changes such as rash, reddening of skin, itching, and dry skin

  • hair thinning

  • painful periods

  • low levels of potassium in the blood which can cause cramps and weakness

  • skin sensation changes, such as burning, tingling or not feeling sensation when touching

  • pain passing urine and blood in the urine, or urinating more often during the day

  • fluid build-up in different parts of the body

  • shaking (tremor)

  • increased risk of getting an infection

  • weight loss

  • inflammation or rash around the drip site

  • feeling cold

  • muscle spasms and stiffness

  • loss of fluid in your body (dehydration)

  • sudden reddening of the skin (flushing of the skin)

  • fluid in the lungs

  • looking pale

  • coughing blood

  • sinus headache and pressure along cheeks and face

  • blocked runny nose

  • swollen tummy

Coping with side effects

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

What else do I need to know?

Other medicines, foods and drink

Cancer drugs can interact with some other medicines and herbal products. Tell your doctor or pharmacist about any medicines you are taking. This includes vitamins, herbal supplements and over the counter remedies.

Pregnancy and contraception

It is unknown whether treatment may or may not harm a baby developing in the womb. It is important not to become pregnant or get someone pregnant while you are having treatment. Let your team know straight away if you or your partner become pregnant while having treatment.

Talk to your doctor or nurse about effective contraception you can use during treatment. Ask how long you should use it before starting treatment and after treatment has finished.

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.


It is not known whether this drug comes through into the breast milk. Doctors usually advise that you don’t breastfeed during this 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.


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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