Ublituximab (Briumvi)

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• Who can take ublituximab (Briumvi)?
• How do you take ublituximab (Briumvi)?
• How does ublituximab (Briumvi) work?
• How well does ublituximab (Briumvi) work?
• Ublituximab (Briumvi) side effects
• What tests do you need with ublituximab (Briumvi)?
• Stopping ublituximab (Briumvi)
• Ublituximab (Briumvi) and pregnancy, breastfeeding and contraception

Who can take ublituximab (Briumvi)?

You can have ublituximab (Briumvi) across the UK if:

• you have ‘active’ relapsing MS. That means you’ve had a recent relapse and/or MRI scans show that you have new, active or growing lesions.

You might be offered ublituximab (Briumvi) as your first DMT. Or you might switch to it if the drug you’re already taking isn’t controlling your MS well enough. 

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How do you take ublituximab (Briumvi)?

You take ublituximab (Briumvi) twice a year in a hospital as an infusion (or ‘drip’). During an infusion a drug goes into your bloodstream through a needle placed in a vein in your arm. Treatment with ublituximab (Briumvi) happens like this:

• up to an hour before each infusion you take medication to make infusion reactions less likely 
• your first infusion is at a lower dose. This infusion takes four hours, with an hour afterwards to check you for infusion reactions
• two weeks later you have an infusion at the normal dose. This lasts one hour, with another hour for checking
• 22 weeks later you have a third infusion. This lasts an hour but with no checks
• all infusions after that last an hour and happen every 24 weeks. That’s nearly every six months

How does ublituximab (Briumvi) work?

Ublituximab (Briumvi) works by targetting B cells. These are special types of cells in your immune system. It’s thought they cause a lot of the damage in MS. 

B cells normally kill viruses and bacteria that get into your body, but in MS they damage nerves. They do this by stripping off the covering of myelin from nerves in your brain and spinal cord. Myelin protects nerves from damage and helps messages travel along them.

Ublituximab (Briumvi) is a monoclonal antibody drug. These artificial antibodies are made in a laboratory. They stick to the surface of B cells and kill them. This means you have fewer B cells that can damage the myelin around your nerves. So you get relapses much less often. 

Ublituximab (Briumvi) is a new kind of monoclonal antibody drug. It’s one of the antiCD20 drugs. These drugs stick to a protein on B cells called the CD20 antigen. That makes them better at targetting B cells, leaving other immune cells unharmed. As a result, these drugs cause fewer serious side effects.

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How well does ublituximab (Briumvi) work?

The effectiveness of ublituximab (Briumvi) is classed as 'high'. Each DMT can be rated as ‘moderate’, ‘good’ or ‘high’ based on two things. One is how much it reduces relapses. The other is how much it slows down disability getting worse.

Monoclonal antibody drugs like ublituximab (Briumvi) are some of the DMTs with the best results against MS. 

The ULTIMATE trials

Two trials compared ublituximab (Briumvi) to a drug already used to treat MS called teriflumonide (brand name Aubagio). These trials were called ULTIMATE I and II. They showed that ublituximab was much better than teriflunomide at reducing relapses. These results led to ublituximab (Briumvi) getting the green light for use in the UK.

Relapses dropped by: 49-59% compared to teriflunomide

This means that in the trials, over two years, on average people saw a drop in one trial of 49% in the number of relapses they had. In the other trial it was a 59% drop. This was compared to people who took teriflunomide.

Disability getting worse 

Both ULTIMATE trials lasted two years and over that time ublituximab (Briumvi) slowed down how fast people’s disability got worse. But it wasn’t any better at doing this than teriflunomide. See how well terifunomide slows disability. 

Other benefits of ublituximab (Briumvi)

NEDA 

In the ULTIMATE trials those on ublituximab (Briumvi) were much more likely to reach something called NEDA. This was compared to people not on this drug. In trials of MS drugs NEDA stands for ‘no evidence of disease activity’. It means there are no signs that MS is still active. There are:

• no relapses
• no new, active or growing lesions (areas of nerve damage that doctors see on MRI scans)
• no worsening of disability 

About 4 in 10 people on ublituximab reached NEDA. Less than 1 in 10 people on teriflunomide did.

Lesions

Ublituximab (Briumvi) prevented almost all new lesions. Depending on the type of lesions, the drug cut them by 90% to 97%. This was compared to what teriflunomide managed to do.

How well does ublituximab (Briumvi) work over many years?

A study from 2026 followed people for five years. Ublituximab carried on working, with no new risks that we didn’t already know about. The risk of a relapse kept falling year by year. During the last four years of the study over 9 in 10 people on ublituximab stayed relapse-free.

Disability didn’t get any worse for 9 in 10 people who took the drug for the whole five years. Almost 1 in 5 saw some improvement in their disability.

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Ublituximab (Briumvi) side effects

The main side effects of ublituximab (Briumvi) are:

• reactions during or after an infusion (usually within 24 hours)
• infections that happen because this drug kills B cells (which fight viruses and bacteria)

Very common side effects (more than 1 in 10 people get them):

Very common side effects include:

• short-lived infusion reactions. In trials nearly half of people had a reaction during their first infusion (or within 24 hours). With the second this happened to fewer than 1 in 10 people. By the fifth infusion it only happened to 1 in 20. If you have a reaction, your infusion can be stopped for a while or slowed down. Medication before each infusion lowers the risk of a reaction. The most common symptoms are:
• fever
• chills 
• headache

An infusion might also cause:

• a faster heartbeat
• a feeling you’re going to be sick
• stomach pain
• sore throat
• a rash, or red or itchy skin
• a faster heartbeat
• feeling sick
• stomach pain
• sore throat
• a rash or red or itchy skin

More very common side effects include:

• infections such as:
• colds or sore throats (nearly half of people got these in trials)
• coughs, chest infections, flu, bronchitis or the more serious infection pneumonia 
• urinary tract infections. These affect your bladder, kidneys or urethra (the pipe your pee comes out of). Around 1 in 10 people got these.

Common side effects (between 1 in 100 and 1 in 10 people get them):

In trials about 1 in 20 people got any of these:

• herpes virus infections like cold sores or shingles
• pain in arms, legs, hands or feet 
• tiredness
• problems sleeping
• a serious infection 

Uncommon side effects (between 1 in 100 and 1 in 1,000 people get them)

• a more serious infusion reaction. This might mean you can’t take the drug again 
• infections in the brain or spine like meningitis or encephalitis 

Ublituximab might also cause liver damage. One way that can happen is if it causes an existing infection of the liver (hepatitis) to become active again. 

Find out more about all the possible side effects of ublituximab (Briumvi)

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What tests do you need with ublituximab (Briumvi)?

Tests before treatment begins

Vaccines

Most DMTs make you more likely to get infections. So before you start this drug your neurologist will check if you have protection against the particular infections it puts you at risk of. Your neurologist will check you’re up to date on your vaccines. This includes childhood ones like chickenpox (that vaccine protects you against shingles) and the MMR vaccine for measles, mumps and rubella. 

If you need any vaccines, you have them a few weeks before you start this drug. That’s because some might not work like they should if you have them once you’re already on it. You can safely have the annual flu jab while taking this DMT. Your MS team or GP can answer questions about vaccinations. 

Read more about vaccines

Blood tests

A blood test will show how well your liver is working, and if you’ve ever had the liver infection hepatitis. Your neurologist needs to know this because ublituximab can cause liver damage, or make hepatitis active again. You can’t take this drug if you have active hepatitis. 

Blood tests will check your immunoglobulin levels. Immunoglobulin is made by your B cells and fights infections.

Before your infusion

To lower the risk of a reaction, before each infusion you’re given a steroid and an anti-histamine (an anti-allergy medicine). You’ll be monitored for an hour during and after your first and second infusion to see how you’re reacting to it. You’ll only need monitoring after further infusions if you had reactions with earlier ones. 

Tests during treatment

You’ll have a blood test around the time of each infusion. This checks how your liver and immune system are working.

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Stopping ublituximab (Briumvi)

You should never stop taking a DMT without telling your neurologist. With some DMTs there’s a risk of ‘rebound’ if you suddenly stop. This is when your MS gets much worse within a few weeks or months. The risk of this with drugs like ublituximab (Briumvi) is possible, but low.

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Ublituximab (Briumvi) and pregnancy, breastfeeding and contraception

Pregnancy

Ublituximab (Briumvi) doesn’t have a licence for use in pregnancy. New guidelines from 2026 from the Association of British Neurologists say no studies exist yet on this drug and pregnancy. They say that, when prescribing ublituximab, doctors can use what they know about ocrelizumab (Ocrevus) to guide them. Ocrelizumab is the same type of drug as ublituximab. And we know a lot about ocrelizumab and pregnancy.  

The guidelines say taking ublituximab (Briumvi) during pregnancy isn’t normally recommended. But you can safely take it if you plan to get pregnant as long as you stop once you get a positive pregnancy test. Once you know for sure that you’re pregnant, you’ll usually have no more infusions until after your baby is born. Speak to your neurologist about stopping the drug. 

Your neurologist might suggest you stop taking the drug a few months before you try to get pregnant. But for some people their neurologist will recommend taking ublituximab during pregnancy.    

Women who’ve just had a baby are more likely to have a relapse. So if you decide to stop this drug to have a baby, it’s recommended that you go back on it a few days after the birth to cut your relapse risk.  

If you want to have a child, discuss this with your neurologist or MS nurse. If you think you’ve become pregnant, let your medical team know at once. Never stop your DMT without first getting their advice. 

Read the 2026 guidelines for neurologists about pregnancy and DMTs.

Breastfeeding

The 2026 ABN guidelines say it’s safe to breastfeed a few days after you give birth when taking antiCD20 drugs like ublituximab (Briumvi). Only very small amounts of these drugs pass into breastmilk, but slightly more is found in the very first mother’s milk. Your medical team can explain more.  

Contraception

The leaflet that comes with ublituximab (Briumvi) says contraception should be used to avoid getting pregnant. The 2026 guidelines on ublituximab and pregnancy say it’s safe to get pregnant while on this drug. But you should stop the drug once you know you’re pregnant. 

So if you don’t want to interrupt your treatment with ublituximab, you need to avoid pregnancy. You’ll need reliable contraception like condoms, the ‘pill’, an implant, injection or coil.   

Read more about pregnancy, breastfeeding and contraception and DMTs

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