Description: Early treatment with the drug interferon slows the progression of multiple sclerosis (MS) in people with the first symptoms of the disease and reduces impairment, an international study shows. The study of 468 people found that 37 percent of those who got every-other-day injections of interferon beta-1b progressed to full-blown MS over three years, compared to 51 percent of those who got inactive injections, according to the report in the Aug. 4 issue of The Lancet.