Medicines on the horizon

It takes a long time to develop new medicines. It is also very expensive.

When a new medicine is developed, it first goes through lots of testing in the lab to find out how it works. This is called preclinical testing. It helps scientists work out what the medicine is likely to do in people.

If a medicine is successful in preclinical testing, it must then be tested in people. These tests are called clinical trials. Early-stage clinical trials involve a small number of people. They check that the medicine is safe and find out the best dose to use. If early-stage trials are successful, the medicine is then tested in larger clinical trials to make sure it works and is safe.

If a medicine is successful in large clinical trials, the company that makes it applies for a product licence. To do this, they submit evidence that the medicine is safe and effective to a regulatory authority. In the UK, this is the Medicines & Healthcare products Regulatory Agency (MHRA). The MHRA decides if the medicine should be approved for use in the UK.

A product licence covers the use of a medicine for a particular illness. This means that some medicines might be approved only for Crohn’s and some only for Colitis. Some might be approved for both. A medicine that is approved for one condition at first could get approval for the other at a later date.

If a medicine is approved for use in the UK, it is then assessed to decide if it should be made available on the NHS.

• The National Institute for Health and Care Excellence (NICE) is the organisation that decides whether treatments should be available on the NHS in England. Wales and Northern Ireland usually follow NICE decisions too.
• The Scottish Medicines Consortium (SMC) is the organisation that decides for Scotland.

Only medicines approved by NICE or the SMC can be prescribed on the NHS. NICE can begin looking at some drugs while they are still at the licensing stage, to help speed up the process. Once a medicine is approved by NICE it must be made available within 90 days of the final decision.

If a medicine is not successful at any stage of the development process, it cannot move to the next stage. Many medicines never reach the clinic.

What is it?

Etrasimod is a type of medicine called an S1P receptor modulator. It sticks to a protein on some white blood cells. This stops the white blood cells travelling into your gut, where they can cause inflammation.

The brand name for etrasimod is Velsipity.

How do you have it?

You have etrasimod as tablets that you take once a day.

Who might it be used to treat?

Etrasimod is being assessed for people with Crohn’s. This assessment is still in development.

Etrasimod has already been approved as a treatment for some adults with Colitis. Read more about the use of etrasimod for the treatment of Colitis.

What stage of development is it at?

Etrasimod has been approved in the UK to treat some people aged 16 or over with Colitis.

Etrasimod is currently being assessed to see whether it is suitable as a treatment for Crohn’s. This assessment is at the clinical trial stage.

When might it be available?

Etrasimod is available throughout the UK for use as an NHS treatment for some people aged 16 years and older with moderately to severely active Colitis.

We do not yet know when the assessment of etrasimod as a treatment for Crohn’s will be complete. As it is currently at the clinical trial stage this is likely to take some time.  

What is it?

Guselkumab is a type of biologic medicine. Biologic medicines are made by a biological process rather than a chemical one. They’re produced in a lab using living cells.  

Guselkumab works by blocking a protein called IL-23. Your immune system naturally makes IL-23 to help you fight infections. But it can sometimes also cause inflammation. By blocking IL-23, guselkumab reduces gut inflammation.

The brand name for guselkumab is Tremfya.

How do you have it?

Guselkumab can be given through a drip into a vein and as an injection under the skin.

Who might it be used to treat?

Guselkumab has been successful in large clinical trials in adults with moderately to severely active Crohn’s and moderately to severely active Colitis.

What stage of development is it at?

On 28 August NICE recommended  guselkumab as a treatment option for people with Crohn’s or Ulcerative Colitis.

For Crohn's

NICE has recommended guselkumab as a treatment option for adults with moderately or severely active Crohn’s. You might be offered guselkumab if:

• You have tried standard treatments or biologic medicines, but they did not work or caused side effects and
• A type of medicine called TNF-alpha inhibitors also did not work or was not suitable for you

For Colitis

NICE has recommended guselkumab as a treatment option for adults with moderately or severely active Ulcerative Colitis. You might be offered guselkumab if:

• You have tried standard treatments, JAK inhibitors or biologic medicines, but they did not work or caused side effects and
• A type of medicine called TNF-alpha inhibitors also did not work or was not suitable for you

When might it be available?

Guselkumab should be available through the NHS in England within 30 days, and in Wales within 60 days of approval.

On 10 November 2025, the SMC also approved guselkumab as a treatment option for adults with moderate to severely active Crohn’s or Colitis.

We have more information on the approval of guselkumab by NICE in our news item.