Multiple sclerosis affects around 400,000 people in the United States and 2.5 million people worldwide. While there is no cure, scientists have found a potential treatment to stop multiple sclerosis progression in its tracks in the form of the experimental drug laquinimod.
Multiple sclerosis (MS) is a disease of the central nervous system, whereby the immune system attacks tissue in the brain and spinal cord. The damage to the tissue called the myelin sheath - an insulated, fatty covering that protects the nerve fibers - affects how nerves carry electrical signals from the brain and the spinal cord.
Currently, MS treatment involves the use of prescription drugs and rehabilitation. MS is a lifelong disease with no known cure. However, the disease can be controlled using both disease-modifying and symptomatic treatments.
Disease-modifying therapies reduce the number of relapses and may help slow disease progression; symptomatic therapies contribute to relieving some of the symptoms.
The research - published online in an American Academy of Neurology medical journal Neurology: Neuroimmunology & Neuroinflammation - discovered that laquinimod might prevent the development of MS or slow down the progression of MS in mice.
"These results are promising because they provide hope for people with progressive MS, an advanced version of the disease for which there is currently no treatment," says study author Scott Zamvil, M.D., Ph.D., of the University of California-San Francisco and a Fellow of the American Academy of Neurology.
Laquinimod is a drug in development for relapsing-remitting MS (RRMS) and primary progressive MS. RRMS is characterized by unexpected, recurring relapses. While in around 80 percent of all patients the disease begins as RRMS, most go on to develop secondary progressive MS after 10 years, which describes gradually increasing disability, without recovery periods.
The precise way in which laquinimod works is unclear. It is suggested that the drug alters the behavior of immune cells and prevents them from entering the brain and spinal cord, thus reducing damage to myelin.
Studies have indicated that laquinimod may have both an anti-inflammatory action and the capacity to protect the nerve structure and function.
For this research, Zamvil and colleagues gave mice that develop a spontaneous type of MS oral laquinimod or a placebo (water) daily. The number of T and B cells in the mice were then analyzed.
Laquinimod reduces clusters of myelin-destroying cells
T and B cells usually assist with the body developing immunity to infection. However, in MS, T and B cells help create antibodies that attack and destroy myelin.
In the first study, which included 50 mice, results showed that of the mice that were given oral laquinimod, 29 percent developed MS, compared with 58 percent of mice that received the placebo. Also noted was a 96 percent reduction in harmful clusters of B cells, which are only found in people with progressive MS. The researchers say that this evidence indicates that the drug may prevent MS.
In the second study, which included 22 mice, laquinimod was administered after mice had developed paralysis. The team observed a reduction in progression of the disease. Compared with the mice receiving the placebo, the mice that were given laquinimod presented a 49 percent decrease of dendritic cells that help create specialized T cells, a 46 percent reduction in T cells and a 60 percent drop in harmful antibodies.
"This study has given us more insight into how laquinimod works. But because this was an animal study, more research needs to be done before we know if it could have similar results in people."
Scott Zamvil, M.D., Ph.D.
People with MS have to receive medication throughout their lifetime. Active Biotech, the manufacturer of laquinimod, points out that, a once-daily oral treatment creates a substantial advantage for patients compared with existing products on the market, all of which need to be injected.