A to Z of MS
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A to Z of MS Cladribine (Movectro)
Cladribine has been studied as a potential oral treatment for relapsing remitting multiple sclerosis. The manufacturers have discontuinued applications for a licence for the drug following negative responses from regulators in Europe and the USA.
Cladribine is currently used as an anti cancer drug under the brand name Leustat.
The results of a two year phase III study (called CLARITY) involving more than 1300 people with relapsing remitting MS were published in January 2010. This study compared two doses of cladribine and placebo and showed a reduction in the relapse rate compared to placebo of 58% with the lower dose and 55% with the higher dose.
In September 2010, the European Medicines Agency (EMA) rejected the licence application for cladribine. The regulators found that the benefits of the drug did not outweigh the risks. They raised concerns about four cases of cancer observed during clinical testing and about the drug's effect on the immune system. The manufacturer, Merck KGaA, appealed, but in January 2011 the EMA confirmed its original decision. The US Food and Drug Administration (FDA) had also asked for further trials before granting a licence.
In June 2011, Merck announced that they were discontinuing their applications for licences for cladribine saying, "We believe that data from ongoing clinical trials are very unlikely to address the FDA's requirements." Cladribine was also withdrawn in Australia and Russia where licences had already been granted.
How cladribine works
As with other chemotherapy drugs used in treating people with MS, cladribine killed off cells in the immune system. In multiple sclerosis, the immune system is thought to attack the myelin sheath around nerves. The theory was that cladribine would slow down this attack.
How cladribine is given
In trials as a treatment for MS cladribine was given orally as a tablet.
Side effects and contraindications
Side effects included infections due to the reduction in white blood cells. Other common side effects in the trials were headaches and symptoms of the common cold.
Giovannoni G, et al.
A placebo-controlled trial of oral cladribine for relapsing multiple sclerosis.
New England Journal of Medicine 2010;362(5):416-426.
Hartung HP, et al.
Development of oral cladribine for the treatment of multiple sclerosis.
Journal of Neurology 2010;257(2):163-170.
Cladribine multiple sclerosis pill rejected by EU regulator.
News item - 24 September 2010.
EU drug watchdog deals another blow to cladribine.
News item - 21 January 2011.
Merck KGaA pulls plug on cladribine on FDA feedback.
News item - 22 June 2011.