A to Z of MS Alemtuzumab

Product name

Campath-1h

Alemtuzumab is an experimental drug treatment for people with relapsing remitting MS. Alemtuzumab is already licensed for use in B-cell chronic lymphocytic leukaemia, a type of cancer.

Results of a trial involving 334 people with relapsing remitting MS that compared alemtuzumab with beta interferon 1a were published in 2008. At the end of the three year trial, 77% of people on a lower low-dose of alemtuzumab and 84% of those on a higher-dose had experienced no relapses, compared with 52% of people receiving beta interferon 1a. The results also showed that compared with beta interferon 1a, alemtuzumab reduced the risk of sustained disability by 71%.

Four year follow-up data from this study were presented at the American Academy of Neurology (AAN) meeting in April 2010. This showed that more people on alemtuzumab remained free of relapses and showed no worsening of disability than the group on beta interferon 1a. However, people on either drug whose MS had got worse in the first few years were excluded from the follow-up.

Two larger phase III studies are under way and are due to report in 2011 and 2014.

A seven year study of 25 people with secondary progressive MS 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

The use of alemtuzumab in this clinical trial was voluntarily suspended in September 2004 following one fatal case of immune thrombocytopenic purpura (ITP), a blood clotting disorder. Other cases of ITP were identified and treated. ITP is not fatal if caught early enough, however, it remains a significant risk.

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.

References

Coles AJ, et al.
The window of therapeutic opportunity in multiple sclerosis: evidence from monoclonal antibody therapy.
Journal of Neurology 2006;253(1):98-108.
abstract

Coles AJ, et al.
Alemtuzumab vs interferon beta-1a in early multiple sclerosis.
New England Journal of Medicine 2008;359:1786-1801.
abstract

Experimental MS drug outperforms standard treatment
News report from AAN
15 April 2010
read online

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