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Diroximel fumarate (Vumerity)

Diroximel fumarate is a licenced treatment for relapsing MS in the UK, sold under the brand name Vumerity. It's licensed in the UK and awaiting an appraisal from the National Institute for Health and Care Excellence (NICE).

Current phase of trial:
Licensed in the UK
Type of MS:
Relapsing MS

About diroximel fumarate

How does diroximel fumarate work?

We don’t know exactly how diroximel fumarate works but it’s chemical structure is similar to dimethyl fumarate (Tecfidera). And it's thought to work in a similar way. This means dampening down immune attacks on myelin and reducing inflammation.

How is diroximel fumerate taken?

As a tablet, twice daily

Latest research

Phase 3 trial – EVOLVE-MS-2

A phase 3 study involving 500 people with relapsing MS finished in July 2020. Participants took either diroximel fumarate or dimethyl fumarate (Tecfidera) for five weeks and compared digestive system side effects.

Results of this trial were published in a peer-reviewed journal in February 2020. The authors found that people taking diroximel fumarate had less gastrointestinal side effects than people taking dimethyl fumarate. Those taking diroximel fumarate said they experienced fewer days of gastrointestinal symptoms compared to dimethyl fumarate.

1.6% of participants stopped diroximel fumarate because of side effects versus 6.0% for dimethyl fumarate. The proportion of people stopping treatment because of digestive problems was 0.8% for diroximel fumarate and 4.8% for dimethyl fumarate.

Find out more about the EVOLVE-MS-2 trial

Read the full research paper

Earlier research

Phase 1 trial

In a phase 1 study involving 35 people without MS, researchers wanted to understand the biological effect and tolerability of diroximel fumarate. The results of the trial were published in a peer-reviewed journal in April 2018. The authors concluded that diroximel fumarate was well tolerated and had a similar biological effect to dimethyl fumarate.

Read the full research paper

Phase 3 trial – EVOLVE-MS-1

A phase 3 study which involved 935 participants with relapsing MS finished in 2019. The objective of the study was to look at side effects of the participants taking diroximel fumarate for two years.

Interim results of this trial involving 696 of the participants were published in a peer-reviewed journal in September 2019. The authors found that after one year of treatment, the annualized relapse rate (the average number of relapses participants had in one year in one year) was 0.16. There was also a significant reduction in the number of new lesions on MRI scans.

Diroximel fumarate was well tolerated. 6.3% of participants discontinued treatment because of side effects. Less than 1% were due to gastrointestinal side effects. The most frequent side effects were flushing (about 44%) and gastrointestinal discomfort (about 31%).

Find out more about the EVOLVE-MS-1 trial

Read the full research paper

What are the side effects of diroximel fumarate?

The most common adverse effects reported from the trials were flushing, dizziness, and constipation.

Diroximel fumarate may cause similar side effects to dimethyl fumarate as it works in a similar way. These may include allergic reaction (such as welts, hives, or difficulty breathing), PML (progressive multifocal leukoencephalopathy - a rare brain infection that can lead to death or severe disability), decreases in white blood cell count, and liver problems.

How does diroximel fumarate compare with current therapies?

Diroximel fumarate compared favourably to dimethyl fumarate (Tecfidera) in the EVOLVE-MS-2 trial in terms of effectiveness and tolerability.

It was also found that people taking diroximel fumarate in the EVOLVE-MS-1 trial had fewer digestive side effects compare to those taking dimethyl fumarate.

When is diroximel fumarate likely to be available?

Diroximel fumarate is a licenced treatment for relapsing MS in the UK following European Medicines Agency (EMA) and Medicines and Healthcare products Regulatory Agency (MHRA) approval.

The treatment was approved by the National Institute for Health and Care Excellence (NICE) in April 2022, and is now available on the NHS in England and Wales. We're hoping to find out whether it will be available in Northern Ireland by summer 2022.