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A to Z of MS Alemtuzumab (Lemtrada)

Product name

Lemtrada - previously known as Campath

Alemtuzumab is a drug treatment for people with relapsing remitting multiple sclerosis. It was licensed by the European Medicines Agency (EMA) in September 2013 and was been approved as a treatment for active relapsing remitting MS by the NHS in 2014.


Results of two large phase III studies were published in 2012.

CARE-MS I was a two year trial that compared alemtuzumab and interferon beta 1a in 581 people in the first few years after diagnosis with relapsing remitting MS who had not had other disease modifying treatments.

Alemtuzumab reduced relapses by 55% compared to interferon beta 1a over the two years of the trial. 78% of people in the alemtuzumab group didn't have a relapse during the two years of the trial compared with 59% of the interferon group. Alemtuzumab also had a greater effect on disease progression, with 8% of the alemtuzumab group and 11% of interferon beta group showing a worsening in their EDSS score.

CARE-MS II was a two year trial that looked at 667 people who had continued to have relapses despite treatment with beta interferon.

The relapse rate of those on alemtuzumab was reduced by 49% compared to those on beta interferon 1a (Rebif), 65% of people in the alemtuzumab group didn't have a relapse during the two years of the trial compared with 49% of the interferon group. The risk of disease progression was also reduced by 42% compared to beta interferon, with 20% of the interferon group showing sustained accumulation of disability compared to 13% of the alemtuzumab group.

Side effects of alemtuzumab included autoimmune thyroid-related problems, which affected about 16% of participants, and ITP (idiopathic thrombocytopenic purpura) a bleeding disorder, which affected about 1%. Less serious side effects were common with 90% experiencing infusion site reactions and 77% reporting infections.

Progressive MS
A seven year study of 25 people with secondary progressive multiple sclerosis showed reduced activity on MRI scans but the people continued to accrue disability.

How alemtuzumab works

Alemtuzumab is a type of drug called monoclonal antibodies. Alemtuzumab acts by killing T-cells which form part of the immune system and which in MS mistakenly attack myelin and cause the inflammation seen on MRI scans. It is thought that the T-cells regenerated following treatment with alemtuzumab will not include those that destroy myelin.

How is alemtuzumab given?

In trials alemtuzumab is given by a course of infusions over three to five days once a year.

Side effects and contraindications

Immune thrombocytopenic purpura (ITP), a blood clotting disorder, has affected about 1% of people involved in trials of the drug. Although potentially serious, ITP is treatable if caught early enough.

Almost a quarter of participants developed thyroid-related side effects. These are treatable but can mean lifelong thyroid medication.

Flu-like symptoms after infusion were reported. As alemtuzumab works by suppressing the immune system, anyone on treatment will be more vulnerable to infections such as colds and viruses for some time after the infusion.


European Commission approves Genzyme's multiple sclerosis treatment Lemtrada (alemtuzumab).
Genzyme press release - 17 September 2013.
read online

Alemtuzumab for treating relapsing‑remitting multiple sclerosis [TA312].
Alemtuzumab approval on the NICE website

Alemtuzumab (Lemtrada).
Alemtuzumab approval on the SMC website

Cohen JA, et al.
Alemtuzumab versus interferon beta 1a as first-line treatment for patients with relapsing-remitting multiple sclerosis: a randomised controlled phase 3 trial.
Lancet 2012;380:1819-28.
Read abstract

Coles AJ, et al.
Alemtuzumab for patients with relapsing multiple sclerosis after disease-modifying therapy: a randomised controlled phase 3 trial.
Lancet 2012;380:1829-39.
Read abstract

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