Photo: Stethoscope

Dimethyl fumarate

Dimethyl fumarate is a treatment for relapsing MS. Its brand name is Tecfidera.

Who can take dimethyl fumarate?

In Scotland, Wales and Northern Ireland you can have dimethyl fumarate if:

  • you have relapsing MS and you’ve had a recent relapse and/or MRI scans show new signs that your MS is active (you have new lesions)

In England you can have this drug if:

  • you’ve had two relapses in the last two years

How does dimethyl fumarate work?

We don't know exactly how it works, but it dampens down inflammation. This may be helpful in reducing the inflammation that causes damage in the brain and spinal cord of people with MS.

Dimethyl fumarate is a tablet you take twice a day.

How well does dimethyl fumarate work?

MS drugs can be put into three groups based on how well they control it. The effectiveness of dimethyl fumarate is classed as 'good'. This puts it between DMTs classed as 'high' effectiveness and those classed as 'moderate'. This is based on how much it reduces relapses and slows down how fast people's disability gets worse.

Relapses dropped by: 53%

This means that in one trial, on average, people saw a 53% 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: 38%

This means that in one trial, on average, people saw a 38% drop in the risk of their disability getting worse. This was compared to people who took a placebo.

What are the side effects of dimethyl fumarate?

Compared to other DMTs the risk of side effects, especially serious ones, is somewhere in the middle.

Up to four in 10 people have one or more of these: flushing (going red in the face), feeling hot, upset stomach or feeling sick.

PML: a very rare side effect

Dimethyl fumarate can increase your chances of getting a rare viral brain infection called PML (progressive multifocal leukoencephalopathy). The risk is extremely small but PML can kill or leave a person seriously disabled. As of the end of 2017 only five cases have been seen in over 230,000 people across the world taking dimethyl fumarate.

There's a virus that makes your risk of getting PML higher. Your specialist can tell from a blood test if you have it. If you do, your MS team will talk to you about PML and what you can do about it.