The first study, FREEDOMS, tested the sphingosine-1-phosphate receptor modulator fingolimod. As previously reported on mims.co.uk, fingolimod significantly reduced the risks of relapse and disability progression during the two-year treatment period. The drug, which is being developed by Novartis, lessens nerve inflammation by effectively ‘trapping' lymphocytes in lymph nodes.
The second study, CLARITY, evaluated Merck Serono's cladribine in 1326 patients over the course of 96 weeks. Cladribine, which is already approved in the UK as an injectable treatment for leukaemia (Leustat), mimics adenosine to interfere with the processing of DNA in blood cells.
CLARITY investigators randomised patients to receive 3.5mg/kg or 5.25mg/kg cladribine, or placebo, given in four or six short courses for a total of 8-20 days per year.
Results showed that both doses of the drug significantly reduced the number of relapses compared with placebo. Annualised relapse rates for the 3.5mg/kg and 5.25mg/kg doses were 0.14 and 0.15 respectively, compared with 0.33 for placebo (p<0.001 for both comparisons).
Cladribine-treated patients also experienced significant reductions in the risk of disability progression and in MRI measures of disease activity.
Adverse events associated with cladribine (lymphocytopenia and herpes zoster) differed from those seen with fingolimod in FREEDOMS (bradycardia and atrioventricular conduction block).
Marketing applications for cladribine and fingolimod were submitted in July and December 2009, respectively.
Biogen Idec applied in January this year for European approval to market a third potential MS tablet, fampridine SR. Unlike cladribine and fingolimod, fampridine is specifically designed to improve walking ability. It works by blocking potassium channel leaks from damaged nerve cells.