SAN FRANCISCO — A new version of a genetically engineered drug called beta-interferon can reduce the incidence of relapses of multiple sclerosis and slow the progression of the disease, researchers said Monday at a meeting of the American Neurological Assn.
The drug is aimed at a relapsing type of MS that affects about 75,000 to 140,000 Americans. In all, about 250,000 to 350,000 Americans have MS.
People with this "relapsing-remitting" MS suffer periodic bouts of symptoms, including fatigue, impaired vision, loss of balance and coordination, slurred speech, tremors and partial or complete paralysis. Patients recover at least partially during the weeks or months after each episode but become progressively disabled.
Doctors now treat many people with relapsing MS with a slightly different form of beta-interferon whose trade name is Betaseron. That drug, approved by the Food and Drug Administration last year, reduces the frequency and severity of attacks. Until a few weeks ago, Betaseron was in such short supply that patients had to enter a lottery for a chance to receive it.
Dr. Lawrence Jacobs of the State University of New York at Buffalo reported on the study, which looked at 301 patients with a relatively mild form of relapsing-remitting MS. They received weekly injections of either the beta-interferon or a placebo.
Researchers measured the progression of the disability with a 10-step scale that looked at weakness or spasticity in the limbs, double vision, slurred speech and lack of coordination. They followed patients over two years to see how many avoided getting worse by a full step on the scale.
At the end of two years, 80% of patients taking interferon had avoided this progression, versus 65% of patients taking the placebo, Jacobs said. Analysis also showed that about 15% of patients taking interferon had three or more MS attacks over the two years, compared with about 35% of patients taking a placebo, he said.