A daily injection to prevent bleeds in haemophilia
Concizumab
A specialist injection given under the skin to help prevent bleeding episodes in people with haemophilia.
What is Concizumab?
Concizumab is a specialist medicine used to help prevent bleeding episodes in people with haemophilia, particularly those who have developed inhibitors (antibodies that stop standard clotting-factor treatment working). It is a monoclonal antibody that blocks a natural brake on clotting called tissue factor pathway inhibitor (TFPI), helping the blood clot more effectively. It is given as a daily injection under the skin. Its most important risk is that it can make the blood too likely to clot, so treatment is carefully monitored, and it is prescribed and supervised by a specialist haemophilia service.
Education and reference only. This is a plain-language guide to Concizumab — 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
Concizumab is a specialist medicine used to help prevent bleeds in people with haemophilia, an inherited bleeding disorder in which the blood does not clot properly. It is especially useful for people who have developed inhibitors, antibodies that make standard clotting-factor treatments stop working. It is a monoclonal antibody, a type of targeted protein medicine, given as a regular injection under the skin to keep bleeding under control over time. It is a preventer used routinely rather than a treatment for a bleed that is already happening, and it is prescribed and supervised by a specialist haemophilia service.
How it works
Normal blood clotting is kept in balance by both clotting factors and natural 'brakes' that stop clots forming too easily. One of these brakes is a protein called tissue factor pathway inhibitor (TFPI). In haemophilia the clotting system is already weakened, so these brakes have an outsized effect. Concizumab blocks TFPI, releasing one of the brakes so the blood is more able to form clots and bleeds are less likely. Because it shifts the balance towards clotting, the dose is set and monitored carefully so the blood does not become too prone to clotting.
Company & origin
Originated / developed by: Specialist manufacturer.
A specialist injectable medicine used in the UK to help prevent bleeds in people with haemophilia, particularly those who have developed inhibitors.
Practical use
How to take Concizumab
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Use it as a regular daily injection under the skin, as your specialist team has trained you.
- Inject it on the schedule you are given rather than waiting for a bleed, as it works by prevention.
- Report straight away any signs of a blood clot, such as leg swelling or pain, breathlessness, chest pain or sudden severe headache.
- Follow your team's plan carefully for treating any breakthrough bleeds while using concizumab.
- Keep all your appointments, as treatment needs careful monitoring by the specialist service.
Weighing it up
Advantages & disadvantages of Concizumab
Advantages
- Helps prevent bleeds, including in people with haemophilia who have developed inhibitors.
- Given as an injection under the skin, which can be done at home after training.
- Offers a treatment option when standard clotting-factor treatment no longer works.
Disadvantages
- Can make the blood too likely to clot, with a risk of unwanted blood clots.
- Needs careful specialist monitoring and a clear plan for breakthrough bleeds.
- Requires regular injections and commonly causes injection-site reactions.
Practical use
Good to know
The most important thing to understand about concizumab is that, because it makes the blood more likely to clot, there is a risk of unwanted blood clots (thrombosis). For this reason treatment is carefully set up and monitored by a specialist team, and you should report symptoms such as swelling, pain or warmth in a leg, sudden breathlessness, chest pain or new severe headache straight away. It is given as a daily injection under the skin, usually by the person themselves or a carer after training, so building it into your routine matters. The most common everyday side effect is a reaction where the injection is given, such as redness, itching or bruising, which usually settles. Your team will give clear guidance on how to manage any breakthrough bleeds alongside it, and on how other clotting treatments are used safely while you are on it.
Who should not take it / use with caution
- People who have had a serious allergic reaction to concizumab should not use it.
- It is used with great caution in people at higher risk of blood clots.
- It should only be used under a specialist haemophilia service that provides training and monitoring.
- It is used with care alongside other clotting treatments, which must be managed by the specialist team.
Monitoring
- Careful setting and review of treatment by the specialist haemophilia service.
- Watching for signs of unwanted blood clots and for injection-site reactions.
- Reviewing how well bleeds are being prevented and adjusting the plan as needed.
Side effects
- Reactions where the injection is given, such as redness, itching, swelling or bruising.
- An increased tendency for the blood to clot, with a risk of unwanted blood clots (thrombosis).
- Headache or rash in some people.
- Rarely, more serious clotting events, which need urgent medical attention.
Key interactions
- It is used with particular care alongside other clotting treatments, which the specialist team manages.
- Treatment for breakthrough bleeds must follow the specialist plan to avoid making clotting too strong.
- Tell your team about all your medicines, as some can affect bleeding or clotting risk.
Available as: A solution for injection under the skin, often given by the patient or a carer.
Answers
Concizumab: frequently asked questions
What is concizumab used for?
It is used to help prevent bleeds in people with haemophilia, particularly those who have developed inhibitors that stop standard clotting-factor treatment working.
How does it work?
It blocks a natural brake on clotting called tissue factor pathway inhibitor (TFPI), helping the blood form clots more effectively so bleeds are less likely.
How is it given?
It is given as a daily injection under the skin, usually by the person themselves or a carer after training from the specialist team.
What is the main risk?
Because it makes the blood more likely to clot, the main risk is unwanted blood clots, so treatment is monitored and any signs of a clot should be reported straight away.
Does it treat a bleed that is already happening?
It is mainly a preventer used routinely; your specialist team will give you a separate plan for treating any breakthrough bleeds.
Authoritative sources
- BNF
- NICE CKS
Building a medicines information resource?
We create evidence-led, dose-free drug and formulary references for teams.