WESTPORT, CT (Reuters Health) Dec 04 - Interferon-beta-1a treatment can significantly slow declines in memory and information processing ability in patients with relapsing multiple sclerosis (MS), according to a report by the Multiple Sclerosis Collaborative Research Group.
"This is the first study of any treatment showing we can decrease the chances of the patients becoming cognitively impaired," Dr. Dennis N. Bourdette, of the Oregon Health Sciences University, in Portland, told Reuters Health.
"The untreated natural history of MS is that 10 to 15 years after onset, over 50% of patients are unemployed because of the MS," Dr. Bourdette pointed out. "The biggest single factor in becoming unemployed is cognitive impairment...By instituting treatment early and decreasing the risk of developing cognitive impairment, we'll keep more patients employed longer. "
A total of 166 patients who had symptoms for at least 1 year and at least 2 documented exacerbations were treated with placebo or interferon-beta-1a (Avonex) 30 mcg intramuscularly once weekly for 2 years. Dr. Bourdette and associates report their results in the Annals of Neurology for December.
"It's interesting," Dr. Bourdette commented, "that the treatment effect on delaying cognitive impairment was more robust than the effects on physical impairment."
After 2 years, results on the information processing and memory component of the comprehensive neuropsychological battery were significantly better in the treatment group than in the placebo group. A similar but nonsignificant trend was observed on the composite measure of visuospatial abilities and executive functions.
The subjects also completed a Brief Neuropsychological battery at 6-month intervals. "There was a separation between groups at 6 months on the brief battery that we think is a reflection on the anti-inflammatory effects of the drug," Dr. Bourdette said.
"The key point is that cognitive impairment, which is at least as devastating as the physical impairment, is a reflection of disease activity in the brain," Dr. Bourdette emphasized. "So there's no reason to withhold therapy just because someone hasn't had an attack that has affected their ability to walk, for instance."
Ann Neurol 2000;48:885-892.