Cladribine is a cytoxic agent that is usually administered through shots or IV infusions used to treat hairy cell leukemia, but a two year study in the U.K., led by Professor Gavin Giovannoni at Barts and The London School of Medicine and Dentistry, showed successful use of a tablet form taken orally in the treatment of MS.
The new study involved 1,320 patients from April 20, 2005 to January 18, 2007 from 155 clinical centers and 32 countries. The patients were given either two or four short treatment courses of Cladribine tablets per year or the placebo and monitored using MRI scans.
Patients allowed in the study had previously received a diagnosis of relapsing-remitting MS, had lesions consistent with MS and had at least one relapse within 12 months before entry and were able to have rescue therapy after week 24 with interferon beta-1a if a patient had more than one relapse or a sustained increase in their expanded disability status scale (EDSS) score.
The results show those who had taken the Cladribine tablets were over 55 percent less likely to suffer relapse and about 30 percent less likely to suffer a worsening in their disability. Cladribine works by suppressing the immune system which attacks the central nervous system of those afflicted with MS and is the first of it's kind in that it is taken orally instead of with shots.
Adverse effects leading to the discontinuation of the study were low but still at least twice as frequent with high-dose Cladribine. Twenty cases of cutaneous herpes zoster (shingles) were recorded among patients receiving it, three of which were serious and three solid tissue cancers (pancreatic, ovarian, and melanoma) occurred among patients receiving low-doses (3.5 mg per kilogram).
Lymphocytopenia (a low white blood cell count) was also frequent in patients receiving Cladribine showing up more so, again, with higher doses.
"The introduction of an oral therapy, particularly one that has no short term side effects and is as easy to use as oral Cladribine, will have a major impact on the treatment of MS," says Professor Giovanni. "However, the use of this drug as a first line therapy will have to be weighed up against the potential long term risks which have yet to be defined."
Sources: New England Journal of Medicine; Queen Mary University of London; Barts and the London School of Medicine and Dentistry; Science Daily