Mifamurtide (Mepact) | Cancer Research UK
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What mifamurtide is

Mifamurtide (pronounced mee-fam-ure-tide) is a type of biological therapy. It is also called by its brand name, Mepact. It is a treatment for osteosarcoma, a type of bone cancer. 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 mifamurtide works

It boosts the immune system to kill cancer cells by making it produce certain types of white blood cells called monocytes and macrophages.


How you have mifamurtide

You have mifamurtide into your bloodstream (intravenously). You can have it through a thin, short tube (a cannula) put into a vein in your arm each time you have treatment. Or you may have it through a central line, a portacath, or a PICC line. These are long, plastic tubes that give the drugs directly into a large vein in your chest. You have the tube put in before or during your course of treatment and it stays in place as long as you need it.

You can read our information about having chemotherapy into a vein.

You have the treatment twice a week, at least 3 days apart. You have it for 12 weeks. Then you have it once a week for another 24 weeks. This makes 36 weeks in total.


Tests during treatment

You have blood tests before starting treatment and regularly during your treatment. The tests check your levels of blood cells and other substances in the blood. They also check how well your liver and kidneys are working.


About side effects

We've listed the side effects associated with mifamurtide. You can use the links to find out more about each side effect. Where there is no link, please go to our information about cancer drug side effects or use the search box at the top of the page.

You may have a few side effects. They may be mild or more severe. A side effect may get better or worse through your course of treatment. Or more side effects may develop as the course goes on. This depends on

  • How many times you've had the drug before
  • Your general health
  • The amount of the drug you have (the dose)

The side effects may be different if you are having mifamurtide with other medicines.

Mifamurtide is a relatively new drug and so we are still learning about the side effects, especially longer term ones. Always tell your doctor or specialist nurse if you have a new symptom or side effect. They can decide whether it is due to the drug or to something else. They can then work out how to help you.

Tell your doctor or nurse straight away if any of the side effects get severe.


Common side effects

More than 10 in every 100 people have one or more of these effects.

  • An increased risk of getting an infection from a drop in white blood cells – it is harder to fight infections and you can become very ill. You may have headaches, aching muscles, a cough, a sore throat, pain passing urine, or you may feel cold and shivery. If you have a severe infection this can be life threatening. Contact your treatment centre straight away if you have any of these effects or if your temperature goes above 38°C
  • Tiredness and breathlessness due to a drop in red blood cells (anaemia) – you may need a blood transfusion
  • Bruising more easily due to a drop in platelets – 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 (known as petechiae)
  • Tiredness and weakness affects 1 in 2 people (50%) during and after treatment – most people find their energy levels are back to normal within 6 months to a year 
  • Confusion occurs in 1 in 2 people (50%) – let your doctor or nurse know if you have this
  • Feeling or being sick happens in 1 in 2 people (50%) but is usually well controlled with anti sickness medicines
  • Loss of appetite affects about 1 in 2 people (50%)
  • Headaches
  • Dizziness – don't drive if you have this
  • Sweating
  • A faster heart beat and a feeling that your heart is racing (palpitations)
  • Changes in blood pressure – it may be higher or lower than normal
  • A cough and breathlessness due to inflammation of the lung or fluid around the lung – tell your doctor or nurse if you have this
  • Difficulty sleeping
  • Pain in your muscles or joints or back, chest, tummy, arms or legs
  • Flu like symptoms, including a high temperature (fever), chills, sweating, aching joints and headaches. These affect nearly everyone at first but usually get better as the course of treatment continues. Taking paracetamol before treatment helps to control this
  • Constipation happens in just under 1 out of 5 people (20%). Your doctor or nurse may give you laxatives to help prevent this but tell them if you are constipated for more than 3 days
  • Diarrhoea – drink plenty of fluids and tell your doctor or nurse if diarrhoea becomes severe or continues for more than 3 days
  • Loss of fertility – you may not be able to become pregnant or father a child after this treatment. Talk to your doctor before starting treatment if you think you may want to have a baby in the future. Men may be able to store sperm before starting treatment

Occasional side effects

Between 1 and 10 in every 100 people have one or more of these effects.

  • Mood changes
  • Blurred vision
  • Hearing loss
  • Ringing in your ears (tinnitus)
  • Loss of balance (vertigo)
  • Indigestion
  • Skin changes, including a rash, reddening, itching and dry skin
  • Hair thinning
  • Girls or women may stop having periods (amenorrhoea) but this may be temporary. Or periods may be more painful
  • Low levels of potassium in your blood – let your doctor or nurse know if you have cramping in your arm or leg muscles, tingling or numbness, palpitations, or feel faint
  • Numbness or tingling in fingers and toes can cause difficulty with fiddly things such as doing up buttons
  • A feeling of tingling, tickling, prickling, pricking, or burning of the skin
  • Loss of sensation in the skin
  • Shaking (tremor)
  • A blue tint in the skin or gums caused by lack of oxygen
  • Swelling in the arms, legs or other parts of the body
  • Chest pain
  • Stomach pain 
  • Weight loss
  • Inflammation around the drip site caused by drugs leaking into the tissues – tell your nurse or doctor if you have any stinging or burning, leakage of fluid, or redness or swelling around your drip site during or after treatment
  • Muscle spasms
  • Feeling cold
  • Drowsiness or sleepiness
  • A sore mouth or throat
  • A blocked nose
  • Pain when passing urine or blood in your urine – tell your nurse or doctor if you have this
  • Cold sores
  • Depression – let your doctor or nurse know if you have this

Important points to remember

Talk to your doctor, pharmacist or nurse about all your side effects so they can help you manage them. They can give you advice or reassure you. Your nurse will give you a contact number to ring if you have any questions or problems. If in doubt, call them.

Other medicines

Tell your doctor about any other medicines you are taking, including vitamins, herbal supplements and over the counter remedies. Some drugs can react together.

Pregnancy and contraception

This drug may harm a baby developing in the womb. It is important not to become pregnant or father a child while you are having treatment and for a few months afterwards. Talk to your doctor or nurse about effective contraception before starting treatment.


Don't breastfeed during this treatment because the drug may come through in the breast milk.



You should not have immunisations with live vaccines while you are having treatment or for at least 6 months afterwards. In the UK, these include rubella, mumps, measles (usually given together as MMR), BCG, yellow fever and Zostavax (shingles vaccine).

You can have other vaccines, but they may not give you as much protection as usual until your immune system has fully recovered from your treatment. It is safe to have the flu vaccine.

It is safe for you to be in contact with other people who've had live vaccines as injections. There can be problems with vaccines you take by mouth (oral vaccines), but not many people in the UK have these now. So there is usually no problem in being with any baby or child who has recently had any vaccination in the UK. You might need to make sure that you aren't in contact with anyone who has had oral polio, cholera or typhoid vaccination recently, particularly if you live abroad.


Related information

On this website you can read about

Biological therapy

Bone cancer



More information about mifamurtide

This page does not list all the very rare side effects of this treatment that are very unlikely to affect you. For further information look at the Electronic Medicines Compendium website at www.medicines.org.uk.

If you have a side effect not mentioned here that you think may be due to this treatment you can report it to the Medicines Health and Regulatory Authority (MHRA) at yellowcard.mhra.gov.uk.

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Updated: 9 December 2015