Questions about MS? Call us on 0808 800 8000
IV infusion

Natalizumab (Tysabri)

Natalizumab is a disease modifying therapy (DMT) for highly active relapsing MS. Its brand name is Tysabri and you take it as an infusion or by injection administered by a nurse.

Read the latest information about DMTs and coronavirus COVID-19

Jump to:

Who can take natalizumab?

How does natalizumab work?

How well does natalizumb work?

What are the side effects of natalizumab?

Who can take natalizumab?

In ScotlandWales and Northern Ireland you can have natalizumab (its brand name is Tysabri) if:

  • you have relapsing MS and you’ve had a relapse in the last year and MRI scans show new signs that your MS is active (you have new lesions). This is despite taking another DMT
  • you have relapsing MS and you’ve had at least two relapses in the last year and MRI scans show new signs that your MS is active. This is happening whether or not you’ve been taking another DMT  

In England you can have this drug if:

  • you have relapsing MS and you’ve had at least two relapses in the last year and MRI scans show new signs that your MS is active. This is happening whether or not you’ve been taking another DMT

Back to the top

How does natalizumab work?

Your immune system makes special types of cells to kill viruses and bacteria. But in MS these cells are thought to target nerves in your brain and spinal cord by mistake. Natalizumab sticks to these cells (called T cells). It stops them before they get into your brain and spinal cord, where they would attack the covering (called myelin) around the nerves there.

Natalizumab is given through a drip (known as an infusion). It takes about an hour, with another hour for you to be monitored.  

You need to go to hospital, but you don't need to stay overnight. You usually have the drug every four weeks. If you have it by injection, you also need to go to a clinic or hospital where a nurse will administer it. The injection takes less time than an infusion.

Back to the top

How well does natalizumb work?

MS drugs can be put into three groups based on how well they control it. The effectiveness of natalizumab is classed as 'high', the best of the three groups. This is based on how much it reduces relapses and slows down how fast people's disability gets worse.

Relapses dropped by: 68%

This means that in a trial, on average, people saw a 68% drop in the number of relapses they had. This was compared to people who took a placebo, a dummy treatment with no drug in it.

Disability getting worse was slowed down by: 42%

This means that in a trial, on average, people saw a 42% drop in the risk of their disability getting worse. This was compared to people who took a placebo.

Back to the top

What are the side effects of natalizumab?

Compared to other DMTs the risk of side effects, especially serious ones, is among the highest.

After an infusion you might get these for a while:

  • hives (itchy skin)
  • headache
  • shivers
  • stomach upset
  • joint pains
  • sore throat
  • feeling sick, tired or dizzy.

PML

Being treated with natalizumab can increase your chances of developing a rare viral brain infection called progressive multifocal leukoencephalopathy (PML). Up to one in four who get PML can die.

The risk of getting PML is small. Four in every 1,000 people who take natalizumab get it. By September 2017 around 750 people with MS who'd taken natalizumab had got PML (out of around 175,000 people across the world taking this drug).

Having a virus called the JC virus makes your risk of getting PML higher. Only one in 10,000 people who don't have this virus get PML. If you do have it, one in 500 people are at the highest risk of getting PML in the first two years of being on natalizumab. After that the risk goes up a lot. If your risk of PML is high your MS specialist will change your treatment, perhaps switching you to another DMT.

If you take natalizumab you'll get blood tests that look for the virus that causes it. If you're at risk of PML you'll be checked for early signs of it. Your MS team will tell you what to look out for and what to do if you notice signs of PML.

Back to the top