Tysabri is approved as single therapy for the treatment of people with relapsing forms of multiple sclerosis (MS) to reduce the frequency of flare-ups and delay progression of physical disability.
After the FDA initially approved Tysabri, the drug's manufacturer took the drug off the U.S. market due to reports of a rare, but serious brain infection called PML (progressive multifocal leukoencephalopathy). But the drug returned to the market after the drugmaker included a risk-minimization program...
In MS, the body turns on itself, attacking myelin, the fatty substance protecting nerve fibers in the central nervous system. That leads to damaged nerve fibers (axons), which hinders nerve impulses from traveling to and from the brain and spinal cord. As a result, numbness, limb weakness, and blurred vision occur. Most patients with MS are diagnosed initially with a form called relapsing-remitting, involving flare-ups followed by remissions.
Four MS experts, consulted by WebMD, agree that the past two or three years have seen noteworthy advances in many areas, including:
New understandings about the genetics of the disease
More drug treatment options, including oral medications expected soon
New techniques to repair the damage caused by MS
New information about the potential causes of the disease
Here are summaries of some recent findings, including updates from the Nancy Davis Foundation for Multiple Sclerosis, which funds basic research through its Center without Walls, a network of research programs.
MS: The Genetic Underpinnings
Researchers have discovered a number of genes in recent years that may make people more susceptible to multiple sclerosis. While the genes do not cause MS, they make people more likely to develop MS when exposed to certain environmental factors or viruses, experts say.
''Genetics [research] is really going at a fast rate now," says Patricia O'Looney, PhD, vice president of biomedical research at the National Multiple Sclerosis Society.
Currently, researchers have identified 34 possible genetic factors, O'Looney says. More are expected to be identified. At least 50 are expected, says Leslie Weiner, MD, professor of molecular microbiology and immunology at the University of Southern California Keck School of Medicine, Los Angeles.
"There are probably multiple genes that contribute," says Jeffrey Cohen, MD, the director of clinical therapeutics at the Cleveland Clinic Foundation's Mellen Center for Multiple Sclerosis Treatment and Research. Some may contribute to the risk of developing MS, he says, and some to how the disease progresses.
Eventually, MS researchers hope genetics will allow doctors to identify people at high risk for the disease and intervene with treatment at very early stages of MS -- perhaps even before symptoms appear.
MS: Drug Treatment Options Grow
Eight medications are approved by the FDA to reduce the frequency of relapses and possibly slow the progression of MS. These drugs are called disease-modifying therapies. So far, most MS disease-modifying drugs must be injected or administered intravenously. The newest drug, Gilenya (fingolimod), approved by the FDA in 2010, is the first disease-modifying MS drug that can be taken orally.