Mavenclad (cladribine) for multiple sclerosis

Last updated Oct. 31, 2025, by Marisa Wexler, MS
Fact-checked by Inês Martins, PhD

What is Mavenclad for MS?

Mavenclad (cladribine) is a short-course oral treatment approved for adults with relapsing forms of multiple sclerosis (MS), including relapsing-remitting MS (RRMS) and active secondary progressive MS (SPMS).

The therapy is taken no more than 10 days a year for two years. It is used to reduce disease relapses, slow the development of lesions, and delay the progression of disability.

Mavenclad works to reduce MS inflammation by lowering levels of certain immune cells, particularly T-cells and B-cells, which play a key role in driving the disease. It mimics purine — one of the building blocks of DNA — and becomes incorporated into the DNA of these cells, disrupting their ability to replicate and causing the cells to die.

Mavenclad is sold in the U.S. by EMD Serono (known as Merck KGaA outside the U.S. and Canada).

Therapy Snapshot

Who can take Mavenclad?

Mavenclad is approved in the U.S. for adults with RRMS and active SPMS.

However, the medication’s prescribing information carries a boxed warning that it can increase the risk of cancer and lead to fetal malformations and fetal death when used during pregnancy.

Due to these safety issues, Mavenclad is generally recommended for patients who have failed to respond to, or could not tolerate, other MS treatments.

In the U.S., the medication is contraindicated, or should not be used, for patients who:

• have cancer
• are pregnant or have the potential to conceive a child but are not planning to use effective contraception during treatment days and for at least six months after the last dose in each treatment course
• plan to breastfeed on Mavenclad treatment days and for 10 days after the last dose
• have an HIV infection
• have active chronic infections, such as hepatitis or tuberculosis
• have a history of hypersensitivity reactions — a type of exaggerated immune response, including anaphylaxis — to cladribine.

It is also not recommended for people with clinically isolated syndrome, which is a first episode of symptoms suggestive of MS.

Mavenclad is also approved in dozens of other countries, but the exact indications may vary. In the European Union, for example, it is approved for adults with highly active, relapsing forms of MS.

How is Mavenclad administered?

Mavenclad is available as 10 mg tablets, which should be swallowed whole with water, without chewing. It can be taken with or without food.

The therapy is given in two treatment courses over two years, with one course per year. In the first course, patients receive two treatment cycles, each lasting about 4-5 days and spaced roughly one month apart. This pattern is then repeated about one year later.

The recommended treatment dose is 3.5 mg per kilogram of body weight (mg/kg). Each yearly course delivers a total of 1.75 mg/kg, split between the two cycles. The number of tablets per cycle depends on a person’s weight, but no more than two tablets should be taken in a single day.

Mavenclad in clinical trials

Mavenclad’s approval in the U.S. was mainly based on data from a Phase 3 trial called CLARITY (NCT00213135), which tested the therapy against a placebo in 1,326 adults with RRMS over the course of two years. Treatment with Mavenclad at the now-approved dose led to:

• a significant reduction in relapse rates by 58% compared with a placebo, with more patients remaining free of relapses for the entire study (81% vs. 63%)
• a significant reduction of 33% in the risk of 3-month sustained disability progression
• significant reductions in MRI activity, with patients on Mavenclad having 73% fewer new or enlarging lesions and 86% fewer lesions with active inflammation.

Mavenclad side effects

The most common side effects of Mavenclad, as seen in MS clinical trials, are:

• upper respiratory tract infection
• headache
• low levels of lymphocytes, a type of immune cell.

Mavenclad carries a boxed warning that it can cause serious issues, including:

• an increased risk of cancer. This is especially more likely if patients receive additional treatment within two years after the first two treatment courses.
• fetal malformations and fetal death. Pregnancy should be excluded in women of reproductive potential and effective contraception is necessary during dosing days and for at least six months after the last dose.

Other side effects associated with Mavenclad, which may be serious, include:

• serious infections, including progressive multifocal leukoencephalopathy, a potentially fatal brain infection
• changes in blood cell levels and other blood parameters
• liver damage
• allergic reactions
• heart failure.

Patients will be routinely monitored for these issues before and throughout treatment and will be advised on the signs and symptoms to look out for. In some cases, Mavenclad treatment may need to be delayed or stopped.

Multiple Sclerosis News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.