Researchers Report on First Drug Shown to Slow Cognitive Impairment in MS Patients

12/04/00    Portland, Ore.

Treatment with Avonex® (Interferon Beta-1a) Has Proven Positive Effect on Cognition.

A new study published in the Annals of Neurology shows that treatment with interferon beta-1a, or Avonex, has a significant beneficial effect on the cognitive impairment often suffered by people with relapsing multiple sclerosis (MS). Researchers at Oregon Health Sciences University report that patients treated with Avonex, an MS therapy already proven to reduce relapses and to slow the progression of the disease, performed significantly better than placebo-treated patients on tests of cognitive function most commonly disrupted by MS. In fact, patients treated with Avonex had a 47 percent reduction in the risk of experiencing cognitive, or mental, deterioration vs. patients who were treated with a placebo.

According to OHSU researchers, about half of all people with MS experience some form of cognitive dysfunction, such as memory loss, slowed information processing and difficulty in problem solving. Cognitive dysfunction, not physical disability, is cited as the most common reason people with MS leave the work force. More than 400,000 people in the United States and more than 1 million worldwide have MS.

"The loss of cognitive abilities is a common, yet under-recognized problem of MS, a disease best known for its debilitating effect on one's physical abilities, not mental abilities." said study co-author Dennis N. Bourdette, M.D., director of the Multiple Sclerosis Center of Oregon at OHSU. "This study shows that proactive treatment with Avonex has a significant overall positive effect on cognitive functioning in patients with relapsing multiple sclerosis."

As part of this multi-center trial, researchers at the Cleveland Clinic's Mellen Center administered a comprehensive battery of neuropsychological tests to a subset of 166 persons with MS enrolled in the original double-blind, placebo-controlled trial of Avonex in relapsing MS.

"According to the study, patients treated with Avonex were almost 50 percent less likely to worsen neuropsychologically compared to those who did not receive Avonex therapy," Bourdette said. "It is clear that cognitive dysfunction should be considered when making decisions regarding disease-modifying therapy in MS."

The positive effects of Avonex were most pronounced on the cognitive functions most frequently affected by MS. These areas include information processing (the ability to focus, sustain and shift attention, particularly when information is presented rapidly) and learning and memory tasks (ability to learn new information and remember it later). There also were benefits in other cognitive functions that often are moderately impaired by MS.

"The research shows that the drug holds great benefits for some MS patients with learning and memory problems," said Muriel D. Lezak, Ph.D., a professor of neurology in OHSU's School of Medicine who was also involved in the research. "As for long-term effects, we can probably expect the onset of serious problems will be significantly delayed."

According to Bourdette, the extensive and irreversible cognitive impairment caused by MS is most likely attributable to cerebral plaque accumulation and brain atrophy. Avonex already has been clinically proven to favorably affect brain atrophy and cerebral lesions.

Previous studies with other MS treatments failed to show the same positive effect on cognition. "MS-related cognitive dysfunction can have a devastating impact on individuals with MS and their families, affecting employment, social functioning and quality of life," said Stephen Reingold, Ph.D., vice president of research, National Multiple Sclerosis Society. "This new report is important because it indicates that treatment with this disease-modifying agent, Avonex, can have significant impact on this important symptomatic problem that affects many with MS."