Vumerity (diroximel fumarate)

Vumerity (diroximel fumarate) is a disease modifying drug (DMD) that is approved for relapsing remitting multiple sclerosis (MS). It is taken as two tablets, twice a day. 

Taking Vumerity reduces the number of relapses you might have by about one half (50%). You have fewer relapses than you might have had without treatment, and disease progression is slower.

Common side effects of Vumerity include nausea and gastrointestinal problems.

Vumerity can be prescribed in England, Wales and Northern Ireland for adults with active relapsing remitting MS who are having relapses or have MRI evidence of MS activity. 

If you live in Scotland, the criteria for prescribing Vumerity is slightly different to that in the rest of the UK. Ask your neurologist if you are unsure whether you are eligible. 

Vumerity has been approved for use on the NHS since 2022. It can only be prescribed by a neurologist.

Vumerity is not recommended during pregnancy.

If you plan to start a family, talk to your MS nurse or neurologist about whether you should continue to take Vumerity until you are pregnant.

If you become pregnant while taking Vumerity, your neurologist or MS nurse may recommend you stop taking it.

You take Vumerity as two pills, twice daily.

Assessment before treatment

Before starting Vumerity, you should have blood and urine tests to measure blood cell counts and to check liver and kidney function.

Assessment during treatment

Once you've started treatment you'll have blood tests every 3 months and urine tests at 3 months, 6 months and then every 6 to 12 months thereafter. These tests monitor your blood cell counts and liver and kidney function. Depending on local practice, you may be able to have the tests at your GP surgery or you may need to attend a hospital clinic.

Common side effects (affecting more than 1 person in 100)

• gastrointestinal discomfort 
• constipation
• flushing
• colds
• diarrhoea
• chest infections
• itchy or red skin
• hair loss

In Vumerity trials, gastrointestinal discomfort was mild to moderate in approximately 30% of participants and severe in 1%. Flushing side effects occurred in 44% of participants and improved in 74% of those affected, on average within 3-4 days.

You can read a complete list of side effects in the manufacturer's Vumerity patient information leaflet. 

Rare or serious side effects

Vumerity can in rare cases damage your liver. Your MS team will monitor you carefully for signs of liver injury.

Progressive multifocal leukoencephalopathy (PML) is a serious brain infection that can often be fatal. It can arise when the immune system in the brain and spinal cord is supressed to the extent that a previously dormant virus is able to cause disease. The risk of PML can carry over once you stop taking a drug that has a suppressive effect on the immune system, because it can take some months for the immune system to recover.

Up to February 2025, there have been no cases of PML reported for people with MS taking Vumerity. However, there have been cases of PML in people taking Tecfidera, which works in the same way as Vumerity. You should alert your neurologist if you notice any new or worsening symptoms.

Read more about PML and the JC virus.

Vumerity is similar to Tecfidera (chemical name dimethyl fumarate).  In the body, both drugs are converted to monomethyl fumarate.  

In common with Tecfidera, the way diroximel fumarate works is not fully understood, but laboratory studies suggest that it may work in two ways.

• Reduces the inflammation caused when the immune system attacks myelin, resulting in less damage to myelin.
• Protects nerve cells from damage caused by chemicals released during the immune attack.

Evidence for the effectiveness of Vumerity has come from two large studies:

EVOLVE-MS-1 - diroximel fumarate

This open-label (ie participants knew they were taking diroximel fumarate) phase III study evaluated the safety and tolerability of diroximel fumarate, taken for approximately 2 years, in more than 1000 participants with relapsing remitting MS. The main purpose of the study was to monitor side effects.

Interim results from 696 participants have been published. After one year of treatment with diroximel fumarate, the annualized relapse rate was 0.16 (down from 0.78 in the previous year). MRI results showed a significant reduction in the number of active MS lesions, compared to when they first joined the trial. Diroximel fumarate was well tolerated, with 6.3% stopping treatment because of side effects, of which less than 1% were due to gastrointestinal side effects. The most common side effects were flushing (affecting approximately 44%) and gastrointestinal discomfort (approximately 31%).

EVOLVE-MS-2 - diroximel fumarate compared to Tecfidera (dimethyl fumarate)

This phase III study recruited 504 participants with relapsing remitting MS who took either diroximel fumarate or Tecfidera for 5 weeks in order to compare gastrointestinal side effects. Participants completed daily questionnaires to assess gastrointestinal symptoms and their impact on daily activities and work. People taking diroximel fumarate experienced fewer days of gastrointestinal symptoms, took less medication for gastrointestinal symptoms and missed less work compared to Tecfidera. The overall proportion of participants stopping treatment because of side effects was 1.6% for diroximel fumarate and 5.6% for Tecfidera. Those who stopped treatment because of gastrointestinal problems was 0.8% for diroximel fumarate and 4.8% for Tecfidera.