An anti-interferon-gamma antibody for HLH
Emapalumab
A specialist antibody medicine used to treat primary haemophagocytic lymphohistiocytosis (HLH), a rare immune condition.
What is Emapalumab?
Emapalumab is a highly specialist monoclonal antibody medicine used to treat primary haemophagocytic lymphohistiocytosis (HLH), a rare and serious condition in which the immune system becomes dangerously overactive. It works by blocking interferon-gamma, a key chemical driving this overactivity. It is given into a vein under specialist care. Its dominant risk is serious infection, including unusual 'opportunistic' infections, so screening and preventive (prophylactic) medicines are used to lower this risk. Infusion reactions can also occur.
Education and reference only. This is a plain-language guide to Emapalumab — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Emapalumab is a monoclonal antibody, a type of medicine designed to target one specific part of the immune system. It is used to treat primary haemophagocytic lymphohistiocytosis (HLH), a rare, life-threatening condition, usually seen in children, in which the immune system becomes massively overactive and damages the body's own tissues. Emapalumab is given into a vein and is used in highly specialist centres, often while waiting for or alongside other treatments such as a bone-marrow (stem-cell) transplant.
How it works
In primary HLH, the immune system spirals out of control, and a signalling chemical called interferon-gamma is a major driver of the overwhelming inflammation. Emapalumab is an antibody that attaches to interferon-gamma and blocks its action, helping to calm the runaway immune response and bring the condition under control. Because it dampens part of the immune system, it also lowers the body's defences against infection, which is why preventing and watching for infections is such an important part of treatment. It is given into a vein on a schedule set by the specialist team.
Company & origin
Originated / developed by: Specialist manufacturer.
A highly specialist medicine used in the UK to treat primary haemophagocytic lymphohistiocytosis (HLH).
Practical use
How to take Emapalumab
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- It is given into a vein by a highly specialist team, on a schedule they set.
- Take any preventive (prophylactic) medicines for infection exactly as prescribed.
- Attend all screening and monitoring appointments before and during treatment.
- Report any fever, chills or sign of infection straight away, as infections can become serious quickly.
- Tell the team about any past infections, such as tuberculosis, and about all your other medicines.
Weighing it up
Advantages & disadvantages of Emapalumab
Advantages
- A targeted treatment for primary HLH, a rare and life-threatening immune condition.
- Can help bring the overactive immune response under control, including while awaiting a stem-cell transplant.
- Works on a specific driver of the condition (interferon-gamma) rather than broadly suppressing the immune system.
Disadvantages
- Increases the risk of serious infections, including unusual opportunistic infections.
- Requires infection screening and preventive medicines throughout treatment.
- Can cause infusion reactions and must be given in highly specialist centres.
Practical use
Good to know
The dominant safety issue with emapalumab is the risk of serious infection. Because it blocks an important part of the immune system's defences, it makes infections more likely, including unusual 'opportunistic' infections caused by germs that rarely trouble people with a healthy immune system, as well as the reactivation of infections such as tuberculosis. To manage this, the specialist team screens for infections before and during treatment and gives preventive (prophylactic) medicines, for example to guard against certain lung and viral infections. Any fever or sign of infection during treatment must be acted on quickly. Reactions during the infusion can also occur. Because it is a complex medicine for a critically ill, often very young group of patients, it is used only in highly specialist centres with intensive monitoring.
Who should not take it / use with caution
- People who have had a serious allergic reaction to emapalumab should not receive it.
- It is used with great care in people with active infections, which are usually treated or managed first.
- Live vaccines should not be given during treatment because of the effect on the immune system.
- It is used only under the care of a highly specialist centre with intensive monitoring.
Monitoring
- Screening for infections, including tuberculosis, before and during treatment.
- Close watching for any signs of infection, with preventive medicines given alongside.
- Checking blood pressure, blood tests and how well the condition is responding.
Side effects
- Serious infections, including opportunistic infections and reactivation of infections such as tuberculosis.
- Reactions during or after the infusion, such as fever, rash or changes in blood pressure.
- High blood pressure and changes in blood tests.
- Rarely, more serious reactions, which the specialist team watches for closely.
Key interactions
- Other medicines that suppress the immune system add to the risk of infection.
- Live vaccines should not be given during treatment.
- Tell the specialist team about all medicines, as some may need adjusting because of changes in inflammation during treatment.
Available as: A solution given into a vein.
Answers
Emapalumab: frequently asked questions
What is emapalumab used for?
It is a specialist antibody medicine used to treat primary haemophagocytic lymphohistiocytosis (HLH), a rare condition in which the immune system becomes dangerously overactive.
How does it work?
It blocks interferon-gamma, a chemical that drives the overwhelming inflammation in HLH, helping to calm the runaway immune response.
Why is infection such a concern?
Because it dampens part of the immune system, it makes serious and unusual 'opportunistic' infections more likely, so the team screens for infections and gives preventive medicines.
Why are preventive medicines given alongside it?
Preventive (prophylactic) medicines help guard against the infections that become more likely when the immune system is suppressed during treatment.
Where is it given?
It is given into a vein in highly specialist centres with intensive monitoring, as HLH is a serious condition affecting critically ill, often very young patients.
Authoritative sources
- BNF
- NICE CKS
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