In preliminary tests, the new drug Antegren dramatically reduced the number of new brain lesions in patients with MS and cut the number of relapses in half. In Crohn's patients, it increased the rate of remission and improved the patients' quality of life. There were few serious side effects.
Both were early studies, and researchers stressed that more definitive results will come from larger, longer studies that are now underway.
"At this stage, these are very promising results," said one of the MS researchers, Dr. David H. Miller of the Institute of Neurology in London. "One hopes that these will be confirmed ... and then one will have an additional effective treatment for people with MS."
The findings were reported in today's New England Journal of Medicine. The studies were funded by the two companies developing the drug, Elan Corp. and Biogen Inc. Some of the researchers have received grants from the companies or worked as consultants for them.
There is no cure for MS or Crohn's and the causes are unknown. In both, the immune system goes awry, resulting in inflammation and damage to brain tissue in MS and to the intestinal wall in Crohn's disease.
MS patients can have loss of balance and coordination, blurry vision and fatigue. Crohn's causes chronic diarrhea, abdominal pain, fever and weight loss.
Current treatments include injections of interferon, which slows the immune system, or anti-inflammatory drugs, including steroids, which ease swelling. Some of the drugs have serious side effects and don't work for all patients, researchers said.
Antegren, also called natalizumab, is the first in a new class of medicines that stops immune cells from leaving the bloodstream and reaching the MS and Crohn's inflammation areas.
Dr. Lars Ekman, president of research and development at Elan, said the companies expect to seek approval for the drug at the end of this year in the United States and Europe. The drug could be available by the end of 2004, he said.