Athlone-based drug developer and its US partner, Biogen Idec, last evening hailed success from a study into the effects of their MS drug, Tysabri in repairing damage to the myelin sheath, a key cause of MS.
The finding is preliminary, from a small study of 62 patients who took natalizumab (Tysabri ), and 26 patients in a control group followed for a year, according to research presented today at the American Academy of Neurology annual meeting in Seattle. Researchers at the Jacobs Neurological Institute in Buffalo, NY, led by Robert Zivadinov, found that natalizumab promoted re-myelination and stabilised de-myelination in lesions and brain tissue that appeared normal.
If this can be proven in larger studies, it’s the sort of finding that could change the risk/benefit equation for the drug. More than 400,000 people in the U.S. suffer from multiple sclerosis, a disease in which the immune system goes haywire and starts attacking the fatty coating around nerve fibres, called myelin. Existing MS drugs mostly work by tamping down the excess inflammation that harms the myelin coating, but they don’t really stop the short-circuiting of nerve signals that gradually robs people of their balance, and ability to walk.
Elan said the study demonstrated that Tysabri promoted regeneration and stabilisation of damage done to the myelin sheath, as measured by advanced MRI technology.
Tysabri is known generically as natalizumab. It is an injection approved for the treatment of multiple sclerosis, a chronic and often disabling disease that attacks the central nervous system.
The companies said that in some patients Tysabri also improves the physical function, fatigue and quality of life of MS sufferer.
In January, Elan said it was seeking new funding to boost and commercialize its drug pipeline, launching a strategic review that could lead to a sale or merger of the company.
The findings will be presented at the 61st Annual Meeting of the American Academy of Neurology.
The two firms' presentation to the Congress will highlight the ability of Tysabri, in some patients, to improve physical function and patient-reported outcomes on cognition, quality of life, and fatigue.
The imaging study, which included a total of 110 subjects, used an advanced MRI technology called the Voxel-Wise MTR to measure lesions and normal brain tissue. The study showed that Tysabri promoted remyelination (repair to the myelin sheath ) when compared to those receiving interferon beta-1a IM and normal controls.
"In the study, 62 MS patients who received Tysabri were followed for 12 months together with 26 MS patients who received interferon beta-1a IM and 22 age-matched and sex-matched normal controls. For each subject, baseline and follow-up MTR volume maps were placed in a common halfway-space. The resulting VW subtraction map was then enhanced via threshold-free cluster enhancement (TFCE ) algorithm, and a significance threshold was determined based on subject-specific Monte Carlo simulation. Supra-threshold volumes (95th percentile ) were quantified for both areas of increasing (remyelinating ) and decreasing (demyelinating ) MTR voxels, which represent a volume value," Elan said.
"What we have seen in these MRI data suggest that Tysabri may have the capacity to repair and possibly restore some of the damaged myelin sheath that protects nerve fibres. Results from this study support the continued investigation of the potential effects of Tysabri on this process," said Robert Zivadinov, M.D., of the Jacobs Neurological Institute in Buffalo, NY, the lead investigator for the remyelination study.
