An anti-FcRn antibody for generalised myasthenia gravis
Efgartigimod
A specialist antibody medicine used to treat generalised myasthenia gravis by lowering the harmful antibodies that cause muscle weakness.
What is Efgartigimod?
Efgartigimod is a specialist medicine used to treat generalised myasthenia gravis, a condition where the immune system attacks the signals between nerves and muscles, causing weakness and tiredness. It works by lowering the level of a type of antibody (IgG), including the harmful antibodies that drive the disease, so muscle strength can improve. It is given by a hospital team, usually as a course of treatments (a cycle) repeated as needed. Because it lowers protective antibodies too, it can increase the risk of infections, and infusion or injection reactions can occur, so it is closely supervised.
Education and reference only. This is a plain-language guide to Efgartigimod — 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
Efgartigimod is a specialist antibody-based medicine used to treat generalised myasthenia gravis in certain adults, particularly those whose disease is driven by acetylcholine-receptor antibodies. Myasthenia gravis is a condition in which the immune system makes antibodies that block the normal signalling between nerves and muscles, leading to muscle weakness and fatigue that gets worse with use. Efgartigimod is given under the care of a specialist neurology team, usually in cycles of treatment rather than continuously, and is used when other treatments are not enough or not suitable.
How it works
In myasthenia gravis, harmful IgG antibodies interfere with the connection between nerves and muscles. Efgartigimod blocks a protein called the neonatal Fc receptor (FcRn), which normally recycles IgG antibodies and keeps their levels high. By blocking this recycling, efgartigimod lets the body break down IgG faster, lowering the overall level of IgG, including the antibodies that cause the disease. This reduction in harmful antibodies allows nerve-to-muscle signalling to recover, so muscle strength improves. Because antibody levels gradually return over time, treatment is given in repeated cycles guided by how the person responds.
Company & origin
Originated / developed by: Specialist manufacturer.
A specialist medicine used in the UK to treat generalised myasthenia gravis in certain adults, given by a hospital team in treatment cycles.
Practical use
How to take Efgartigimod
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- It is given by a hospital or specialist team, as an infusion into a vein or an injection under the skin, depending on the product used.
- It is usually given as a course of treatments over a few weeks (a cycle), with further cycles given as needed based on your response.
- Attend all your appointments so the team can give each treatment and monitor how you are doing.
- Report any signs of infection, such as fever, sore throat, cough or feeling generally unwell, to your team promptly.
- Tell your team about all your medicines and keep your vaccinations up to date where they advise, as your defences against infection can be lowered.
Weighing it up
Advantages & disadvantages of Efgartigimod
Advantages
- Can improve muscle strength and reduce symptoms in generalised myasthenia gravis when other treatments are not enough.
- Given in cycles rather than continuously, which suits some people's treatment pattern.
- Targets the harmful antibodies that drive the disease by lowering IgG levels.
Disadvantages
- Lowers protective antibodies as well, which can increase the risk of infections.
- Can cause reactions during or after the infusion or injection.
- A specialist hospital treatment that needs repeated visits and close monitoring.
Practical use
Good to know
The most important thing to understand is that efgartigimod works by lowering IgG antibodies, and this includes the protective antibodies that help fight infection, so it can increase the risk of infections; any signs of infection such as fever, sore throat or a cough should be reported promptly. Treatment is given as cycles rather than continuously, and the timing of further cycles is based on how your symptoms respond, so it is normal for effects to build up and then ease before the next cycle. Reactions during or after the infusion or injection can happen, which is why it is given by a hospital team who can watch for and manage them. It is a specialist treatment, so it is always supervised by a neurology team who will check that vaccinations are up to date where possible and monitor you closely throughout.
Who should not take it / use with caution
- People who have had a serious allergic reaction to efgartigimod should not receive it.
- It is used with particular care in people with an active or serious infection, which is usually treated first.
- It should only be used under specialist supervision, with attention to infection risk and vaccination status.
Monitoring
- Reviewing your muscle strength and symptoms to judge how well each cycle is working and when the next is needed.
- Watching for signs of infection during and between cycles.
- Checking vaccination status and overall wellbeing throughout treatment.
Side effects
- A higher chance of infections, such as chest, urine or airway infections, because protective antibodies are lowered.
- Headache or reactions during or after the infusion or injection, including reactions where the injection is given.
- Less commonly, allergic-type reactions, which the hospital team watch for during treatment.
Key interactions
- It can lower the levels of other antibody-based medicines, so tell your team about all the treatments you have.
- Live vaccines are generally avoided while protective antibodies are lowered, so vaccination plans should be discussed with your team.
- Tell your team about all your medicines, as your overall treatment for myasthenia gravis is balanced together.
Available as: A solution given as an infusion into a vein, or as an injection under the skin, by a specialist team.
Answers
Efgartigimod: frequently asked questions
What is efgartigimod used for?
It is used to treat generalised myasthenia gravis in certain adults, by lowering the harmful IgG antibodies that disrupt the signals between nerves and muscles, so muscle strength can improve.
Why might I be more prone to infections?
Efgartigimod lowers IgG antibodies, and this includes the protective antibodies that help fight infection, so you may be more prone to infections; report any signs of infection to your team promptly.
Why is it given in cycles?
Antibody levels gradually return over time, so treatment is given as a course (a cycle) and repeated as needed, with the timing based on how your symptoms respond.
How is it given?
It is given by a hospital or specialist team, either as an infusion into a vein or as an injection under the skin, depending on the product used.
Can I have my usual vaccinations?
Because your defences can be lowered, live vaccines are generally avoided and other vaccinations are best planned with your team, so discuss any vaccines with them first.
Authoritative sources
- BNF
- NICE CKS
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