Clotting factor concentrate for von Willebrands disease

Treatment for von Willebrand’s disease with von Willebrand clotting factor concentrate

Your child has a form of von Willebrand’s disease (VWD) which means that they may eventually need treatment with von Willebrand factor (VWF) concentrate. This is either to treat a bleeding episode, or to prevent bleeding at the time of surgery.

The treatment is to replace one of the clotting factors that are low in VWD.

What does the treatment look like?

Until recently, the only VWF concentrate came from the donated blood of lots of blood donors, contributing to batches of factor. This is called ‘plasma derived’ VWF.

It comes in the form of a white powder in a bottle which is dissolved in water, and then injected into a vein. Your child may have received one of these plasma derived products in the past.

The names of these products we have used at Sheffield Children’s Hospital include:

• Haemate P
• Voncento
• Wilate

What is the history of it?

The treatment your child may have been given (or that you may have at home for emergencies) has gone through numerous safety steps. These include donor screening and viral inactivation procedures. There have been no cases of transmitted blood-borne infections in over 30 years.

However, the inherited bleeding disorders community has been committed to using artificial concentrates (also called ‘recombinant’) when these are available. These have also been used for another bleeding disorder called haemophilia since the 1990’s. Some people prefer this, as it is not possible to prevent all future risks of infections being transmitted in plasma-derived products.

What are the options now?

There is now a recombinant (artificial) VWF concentrate. This is genetically engineered and does not come from donated blood.

This was developed because in the 1970s and 1980s, many people with bleeding disorders who were treated with VWF concentrate from donated blood at that time, were given infections, such as hepatitis and HIV. The safety steps that are now in place to prevent this did not exist at that time.

As with all new medicines, recombinant VWF (Vonicog alpha, trade name Veyvondi) has to be assessed through clinical trials so that it can gain a licence.

At the moment, all new medicines go through clinical trials in adults before children. This means children have delayed access to the same treatment.

In adults, the licence was approved in 2020, whereas it was approved for older children in 2023.

NHS England: Commissioning medicines for children in specialised services

The children’s clinical trials have not been completed yet, and there will not be a licence until at least 2025.

Recombinant VWF has been available to adults since 2020 and older children since 2023 for treatment of bleeding and around surgery. It is not yet approved for preventative regular injections called prophylaxis.

Now NHS England has agreed to fund it for younger children for the same reasons, ahead of the children’s licence.

The teams treating children with VWD around the country have been requesting this since 2021. The agreement in 2024 follows on from a recommendation in the infected blood inquiry report (V1.0 Aug 2024) which states that recombinant coagulation factor products should be offered in place of plasma derived ones, where clinically appropriate.

Which is the best choice for my child?

Both plasma derived and recombinant VWF will work well to stop or prevent bleeding in your child.

The plasma derived VWF concentrate that your child may have already had, or has for emergencies, has been shown to be safe and effective over many years.

When recombinant VWF has a licence for children we will move all our patients to this for bleed and surgical treatment.

Although the recombinant product (Veyvondi) does not yet have a licence for children, we are recommending that we use the it if your child needs factor concentrate to avoid unnecessary exposure to blood products.

Some patients with more severe VWD and very low FVIII (factor 8) levels, may also need a dose of recombinant factor VIII to give alongside the Veyvondi. Both of these proteins are present in the plasma-derived concentrates.

I still feel uncomfortable – what if I do not want my child to have it?