Acadia postpones plans for Daybue in the UK

07/10/2025

Acadia, the company who makes the only FDA approved drug for Rett syndrome has recently shared that they will not be asking for UK approval right now. This is sad news for families who were hoping to have access to Daybue here in the UK.

Why is this happening?

The company says the UK is a very expensive place for smaller medicine companies to do business.

But there are also other reasons:

  • How well Daybue works: In the big trial, some children improved, but many showed little or no change.
  • Side effects: Some children stopped taking the medicine because of tummy problems.
  • High cost: In the USA, Daybue costs over $500,000 per year. In the UK, the NHS needs to see good results before paying for such an expensive medicine.

Because of all these things together, Acadia has decided not to continue in the UK at this time.

Does this mean other Rett treatments won’t come?

No. This does not mean the same thing will happen with every Rett treatment.

Some new treatments look much more promising. If a medicine shows clear, strong benefits, the NHS has sometimes agreed to pay even very high prices.

For example:

  • Some new cancer medicines are very expensive, but have still been approved in the UK when they clearly help patients.
  • Other rare disease treatments have been given the go-ahead when they showed good results.

This shows that if a Rett treatment works well, it can get approved here too.

What happens next?

We know this news is disappointing. But there are other Rett treatments in development. Some are gene therapies that may help much more than Daybue.

At Reverse Rett, we are:

  • Watching all the research closely.
  • Working with doctors, families and the NHS to make sure the UK is ready.
  • Fighting for fair access to new medicines that show real benefit.

Our message to families

This setback with Daybue is hard, but it is not the end. The Rett research pipeline is still moving forward. We remain hopeful, and we will keep working every day until effective treatments are available for our children here in the UK.

You can read a more detailed article about our response to Acadia’s news here.