Cladribine (Mavenclad)

Cladribine is a disease modifying therapy (DMT) for relapsing MS. Its brand name is Mavenclad and you take it as a tablet.

Read the latest information about DMTs and coronavirus COVID-19

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Who can take cladribine (Mavenclad)?

You can take cladribine (Mavenclad) if:

  • you have ‘highly active’ relapsing MS. This means you’ve had two or more disabling relapses in the past year and MRI scans show you have more, or bigger, lesions. Guidelines call this ‘rapidly evolving severe relapsing remitting MS’


  • despite taking a DMT, you’ve had a relapse in the past year and new or bigger lesions can be seen on your MRI scans

COVID-19, cladribine and MRI scans

Because of COVID-19 it may now be harder to get MRI scans. So since February 2021 neurologists can prescribe cladribine where it’s appropriate but without the need for one. Once it becomes easier to get MRI scans again, neurologists are likely to go back to needing scans before they can give people this drug.

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How does cladribine (Mavenclad) work?

Cladribine (Mavenclad) kills certain types of blood cells made by your immune system. These white blood cells (or lymphocytes) are called T and B cells.

These cells normally attack viruses and bacteria that get into your body. But in MS they attack the covering (called myelin) around the nerves in your brain and spinal cord. Cladribine stops these cells, especially the B cells, from getting into your brain and spinal cord, so they can’t damage the nerves there.

You take this drug as a tablet in two courses. Each treatment course consists of two treatment weeks, one at the beginning of the first month and one at the beginning of the second month. This is then repeated a year later. Hopefully the two courses will control your MS and you won’t need any more treatment.

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How well does cladribine (Mavenclad) work?

MS drugs can be put into three groups based on how well they control it. The effectiveness of cladribine (Mavenclad) is classed as 'good'. This puts it between the 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.

In a large trial:

Relapses dropped by 58%

This means that during the two years of the trial, on average, people saw a drop of 58% in the number of relapses they had. This was compared to people who took the placebo. During the two years after the trial ended this drop was kept up.

Disability getting worse was slowed by 33%

This means that in the trial, on average, people saw a drop of 33% in the risk of their disability getting worse (compared to people who took the dummy pill).

Over the two years the trial lasted, nearly half of people (46%) had no signs their MS was still active.

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What are the side effects of cladribine (Mavenclad)?

Cladribine (Mavenclad) doesn’t weaken your immune system as much as some other MS drugs. So the risk of getting infections isn’t as high as with some DMTs.

The most common side effect is a drop in the number of your white blood cells that fight infections (lymphopenia). This is seen in about one in four to one in three people. Cladribine is meant to make this happen but this drop can last a long time and be severe.

Other side effects can include a slightly higher risk of getting headaches, colds, and infections caused by the herpes viruses. This includes the skin rash shingles, which one in 50 people on the drug get. You’ll be vaccinated against some infections like chicken pox before you take cladribine. About three in 100 people get some hair loss or thinning of their hair.

An earlier study seemed to show a higher risk of cancer but we now know this isn't the case.

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Cladribine (Mavenclad) and pregnancy, breastfeeding and contraception


Cladribine (Mavenclad) could harm an unborn baby. So you mustn’t get pregnant while being treated with this drug, or for six months after your final course of tablets. Six months is this drug’s ‘washout period’. That’s how long it takes for levels of it in your body to reach a level where it’s safe to get pregnant.

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


It’s not clear if cladribine (Mavenclad) gets into breast milk. So women must not breastfeed while being treated with cladribine or for a week after their last dose.


If you can get pregnant, you’ll need reliable contraception (like the ‘pill’, condoms, an IUD or implant) while you’re being treated with cladribine (Mavenclad), and for six months after your final course of tablets. It’s recommended that if you’re on the pill, you also use a barrier method of contraception (like a cap, diaphragm or condoms to be extra safe for four weeks after finishing each course of tablets.

Cladribine (Mavenclad) can affect the quality of sperm for up to six months after your last course of tablets. This drug can also damage sperm, putting at risk any baby that’s conceived. So men need to use reliable contraception like condoms while taking this drug (and for six months after finishing the last course). Your neurologist can give you more advice about fertility and contraception.

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