US approves drug for multiple sclerosis

Symptoms of multiple sclerosis vary and wax and wane. About half the 350,000 Americans with MS cannot take existing drugs, such as the beta-interferons, because of side effects.

This new medicine, initially called Antegren and renamed Tysabri, is a so-called monoclonal antibody that targets the immune system and stops the inflammatory process that is the key to the disease. It is given monthly through an intravenous drip in a doctor’s office.

‘‘This is a completely new way to treat MS,’’ Gudesblatt said. ‘‘If you can hold the attacks down and keep the disabling symptoms away, people can live their lives.’’

In the most common form of MS, a worsening of neurologic function occurs intermittently. There is growing scientific acceptance that MS is an autoimmune disorder. The immune system, which usually keeps the body safe from foreign organisms, attacks itself. With MS, the target is the brain and spinal cord.

Scientists at Biogen Idec of Cambridge, Massachusetts and Elan Pharmaceuticals of Dublin, teamed up to design a molecule that stops immune cells from travelling into the brain. When immune cells do get into the brain, there is an inflammatory response and this leads to the classic lesions observed in the MS-affected brain.

The FDA was so impressed with the drug’s benefit to patients in a two-year multi-center study that after the first year the approval process was accelerated. Even though the drug soon will be available by prescription, scientists will continue to treat and follow patients in the studies.

In one study, scientists found the drug reduced the frequency of relapses by 66 per cent compared with the placebo. In the second trial, patients taking the MS beta interferon drug Avonex added the experimental drug to their treatment. At the end of a year, those on combination treatment had a significant reduction in relapses. There were no serious side effects, but some patients developed infections, rashes, depression and gallstones. —LAT-WP