Alemtuzumab (Campath 1-H, Lemtrada)

Current phase of trial: phase III

Type of MS: relapsing remitting MS.

Research into: preventing damage caused by MS

How is it taken? Intravenous infusion once per year.

• How does it work
• Latest research
• Side effects
• How does it compare to current therapies?
• Further work
• When is it likely to become available?

How does it work?

Alemtuzumab was developed to treat certain types of leukemia and lymphoma (cancers of the immune system).

It binds to and kills white blood cells (immune cells) thereby stopping the immune cells from entering the brain and attacking myelin (which is the cause of damage in MS).

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Latest research:

In October 2008 researchers in Cambridge announced results of a Phase II clinical trial involving 334 people with early stage, active relapsing remitting MS. The trial was conducted over a three-year-period and compared annual infusions of alemtuzumab with the drug beta-interferon.

Of the people taking alemtuzumab over a three-year-period:

• There was a 71% reduction in disability progression compared with people taking betainterferon
• There was a 74% reduction in the relapse rate per year compared with people taking betainterferon.
• The researchers measured the ten point Expanded Disability Status Scale (EDSS) score before and after treatment. On average participants taking alemtuzumab experienced an improvement in disability at 6 months that was sustained for the 3 years. In comparison, participants taking beta-interferon showed a progression in disability.

Results of a further five year follow-up study show that:

• Participants who received alemtuzumab were three times less likely to have a relapse over the course of a year compared with those receiving beta-interferon-1a.
• Nearly 90 percent of alemtuzumab-treated participants were free of accumulated disability, compared with 75 percent of participants taking interferon beta-1a.

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What are the side effects?

Overall, side effects experienced by participants taking alemtuzumab were more severe than those taking beta-interferon. The five year follow-up data showed that:

• About 30% of participants taking alemtuzumab suffered from thyroid disorders (treatable conditions where immune cells attack the thyroid gland and cause an hormonal imbalance).
• 6 participants on the trial (five taking alemtuzumab and one taking beta-interferon-1a) developed a condition called immune thrombocytopenic purpura (ITP - a failure of the blood to clot). One of these participants died after ITP was not detected early. The others were treated without problems.
• 66% of participants taking alemtuzumab experienced infections (compared with 47% of participants taking beta-interferon).
• One participant receiving alemtuzumab was diagnosed with an autoimmune kidney disease. Following detection the participant was treated successfully and is in remission. Other side effects included infusion reactions.

The design of future trials involving alemtuzumab has changed to monitor people for these side effects more frequently and to detect and treat complications as early as possible.

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How does it compare to current therapies?

Alemtuzumab was more successful at reducing the relapse rate and accumulation of disability compared with beta-interferon and appeared to be a more effective treatment.

Despite this, alemtuzumab was associated with a number of side effects that beta-interferon was not associated with.

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What further work is going on?

Two phase III clinical trials are underway to investigate the effectiveness and safety of alemtuzumab in relapsing remitting MS. Both trials are fully recruited and will compare an annual dose of alemtuzumab with Rebif treatment over two years.

1. CARE-MS 1: Comparison of Alemtuzumab and Rebif® Efficacy in Multiple Sclerosis, Study One
(clinical trial identifier NCT00530348 in clinicaltrials.gov) is for people with multiple sclerosis who have never had any previous treatment. The company making alemtuzumab reported positive results in July 2011, full results are expected later in the year.

2. CARE-MS 2: Comparison of Alemtuzumab and Rebif® Efficacy in Multiple Sclerosis, Study Two
(clinical trial identifier NCT00548405 in clinicaltrials.gov) is for people with multiple sclerosis who have had one or more relapses whilst taking beta-interferon or glatiramer acetate. Results are expected in autumn 2012.

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When is it likely to become available?

Alemtuzumab is already licensed in the UK for certain types of blood cancer, but a licence needs to be obtained for specific use in MS before it can be prescribed on a wide basis.

This will depend on the results of the ongoing clinical trials.

The company making alemtuzumab have confirmed plans to apply for a licence to use alemtuzumab in people with MS early in 2012, if clinical trial results look promising.

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