As with any medicine, the MHRA will keep the safety and effectiveness of concizumab under close review.
The Medicines and Healthcare products Regulatory Agency (MHRA) has approved the medicine concizumab (brand name: Alhemo) to prevent or reduce the frequency of bleeding episodes (prophylaxis) in people aged 12 years and older with haemophilia A or B with inhibitors.
Haemophilia is a rare, inherited condition that affects the way blood clots. People with haemophilia A or B are at higher risk of bleeding because they lack proteins that help the blood clot (clotting factor VIII for haemophilia A and clotting factor IX for haemophilia B).
The active substance, concizumab, which acts independently of factor VIII and factor IX, works by blocking a natural protein that prevents blood from clotting (known as tissue factor pathway inhibitor). By inhibiting this protein, concizumab increases Factor Xa activity, a component in the blood clotting (coagulation) process, allowing the blood to clot more effectively and prevent bleeding in people with haemophilia.
Concizumab is injected subcutaneously (under the skin) daily.
A full list of side effects can be found in the Patient Information Leaflet (PIL) or the Summary of Product Characteristics (SmPC), available on the MHRA website within 7 days of approval.
As with any medicine, the MHRA will keep the safety and effectiveness of concizumab under close review.
Anyone who suspects they are having a side effect from this medicine are encouraged to talk to their doctor, pharmacist or nurse and report it directly to the Yellow Card scheme, either through the website ( https://yellowcard.mhra.gov.uk/ ) or by searching the Google Play or Apple App stores for MHRA Yellow Card.
Notes
The new marketing authorisation was granted on 6 October 2025 to Novo Nordisk.
