Evidence showing treatment benefits of beta interferon for multiple sclerosis

Results of a European study in this week’s issue of THE LANCET provide further evidence that patients with early symptoms of multiple sclerosis given a weekly injection with interferon beta are less likely to progress to full clinical disease after two years follow-up. The study showed that the drug reduced patients’ loss of brain tissue compared with individuals given placebo.

Early findings from the ETOMS (early treatment of multiple sclerosis) trial (see Lancet 2001; 357: 1576-82) showed encouraging results for interferon beta in delaying the progression of full clinical symptoms of multiple sclerosis compared with placebo. The same investigators led by Massimo Filippi (Ospedale San Raffaele, Milan, Italy) and colleagues assessed whether this drug can also reduce the rate of patients’ brain-volume decrease.

After two years follow up, around a third (31%) of 131 patients given interferon beta and just under half (47%) of 132 patients given placebo converted to clinically definite multiple sclerosis.

The degree of brain-tissue loss assessed by MRI scans was greater among patients given placebo (1.68% loss over the two-year period) compared with individuals given beta interferon (1.18% tissue loss).

Dr Filippi comments: “This study has confirmed in a large cohort of patients at the earliest clinical stage of multiple sclerosis that brain parenchymal loss takes place rapidly, and has shown that 22 mg interferon beta-1a, given subcutaneously once weekly, can alter this process significantly. Whether higher or more frequent doses would enhance or reduce this effect remains untested.”

In an accompanying commentary (p 1463), David Miller (Institute of Neurology, London, UK) cautions that it may be premature to conclude that a beneficial effect of interferon beta (or any other treatment) on global brain-atrophy itself will produce a long-term reduction in disability. Nevertheless he concludes: “The report by Filippi and colleagues is encouraging and commends investigators to include brain atrophy as an outcome measure in future trials of potential disease-modifying treatments in multiple sclerosis.”