Only Half of MS Patients Respond to Interferon Therapy

Nov. 13 -- WEDNESDAY, Nov. 12 (HealthDay News) -- New research suggests that treating multiple sclerosis with the drug interferon only works for about half of patients.

Interferon works by reducing inflammation and can reduce the relapse rate of multiple sclerosis (MS) while slowing the progression of disability.

Dr. Moses Rodriguez, a professor of neurology and immunology at the Mayo Clinic, who was not involved with the study, thinks the finding provides more evidence that MS is not one disease.

"This finding fits well with our results and fits our clinical observation," Rodriguez said. "We see that there are four distinct patterns of MS. Two of the patterns are associated with inflammation, and two of the patterns are not associated with very much inflammation."

The new interferon study supports that finding, Rodriguez said, adding, "You have either responders or non-responders."

This is true for all current MS treatments, Rodriguez explained. For the type of multiple sclerosis called chronic progressive MS, there is no treatment, he noted. "There are probably a number of diseases hiding under this umbrella we call MS," he said.

The interferon report was published online Nov. 10 in Archives of Neurology and was expected to be published in the January 2008 print issue of the journal.

For the study, researchers led by Dr. Francesca Bagnato, of the U.S. National Institute of Neurological Disorders and Stroke, looked at brain MRI scans of 15 MS patients who were given shots of interferon -- a standard MS treatment -- every other day over 36 months.

The researchers found that eight patients saw a 60 percent reduction in their brain lesions, which are typical of MS; these patients were classified as "responders." Among the seven "non-responders," three had an initial reduction in lesions, two never reached the 60 percent reduction level, and two did not respond during the first six months of therapy but did reach a 60 percent reduction in lesions later on.