In the MS Pipeline: A Vaccine, and a Drug That Fights Fatigue
MS is thought to occur when immune cells called T cells start attacking nerves as if they were foreign invaders, say researchers at Baylor University in Houston. In an attempt to target this problem, they developed a revolutionary vaccine, comprised of normal cells that were inactivated by subjecting them to radiation. The theory was that by injecting these inactivated T cells back into the body, the doctors could stimulate the healthy components of the patients' immune systems to fight the actions of the bad cells and suppress the malfunctioning T cells.
The Texas investigators, led by Jingwu Z. Zhang, MD, vaccinated 65 MS patients with the inactivated T cells and monitored them for 24 months. The patients had a significant improvement in disability, and fewer relapses. Zhang and his colleagues suggest that the vaccine may work by decreasing the action of the abnormal T-cells and promoting the production of anti-inflammatory proteins by the normal parts of the immune system.
In an effort to relieve the severe fatigue that afflicts many people with MS, researchers at Ohio State University in Columbus and Kaiser-Permanente in San Diego looked at the effects of a drug called Provigil. The drug is now prescribed to treat narcolepsy, a condition whose chief characteristic is uncontrollable bouts of falling asleep during the day. The doctors suggest that Provigil may also help treat fatigue associated with other conditions, such as chemotherapy and chronic fatigue syndrome.
More than three-quarters of MS patients suffer from fatigue, says Kottil W. Rammohan, MD, a neurologist at Ohio State University in Columbus. "It is something that is there with them all the time, and it can be disabling," Rammohan says.
The cause is unknown, but some doctors think it is related to a chemical imbalance in the brain, possibly associated with the inflammation that is characteristic of MS. People whose physical symptoms are most serious do not always suffer the worst fatigue, Rammohan says. In fact, it may be the other way around -- with the fatigue being most severe in people whose physical problems are otherwise mild.
Currently, doctors routinely prescribe two drugs, Symmetrel and Cylert, to treat MS-associated fatigue, but their effectiveness has not been confirmed -- and Cylert has been shown to damage the liver. Acting on a suggestion from a colleague, Rammohan and his co-workers decided to test Provigil, a drug with caffeine-like effects.
The investigators studied 72 patients whose fatigue was severe but whose physical disability was not as serious. These are "people who are up and about and working -- or trying to work -- but they are hampered by the fatigue," Rammohan says.
During four weeks in which the patients took Provigil at a low dose, there was a "very highly statistically significant" change in their fatigue levels, Rammohan says. Not only did tests at a higher dose fail to produce a measurable improvement, but some patients complained of anxiety and jitteriness. Headache was the most common side effect at both doses.