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The Pharmaceutical Journal
Vol 268 No 7196 p597-604
4 May 2002

Related websites
The Lancet (www.thelancet.com)

Interferon beta-1b every other day more effective than weekly interferon beta-1a

Interferon beta-1b administered every other day is more effective than weekly interferon beta-1a for multiple sclerosis (MS), researchers say.

Professor Luca Durelli, department of neuroscience, University of Turin, Italy, and colleagues compared the efficacy of the two treatments in 182 patients with relapsing-remitting MS. Three interferon beta preparations (which differ in terms of dose and frequency of administration) are approved for treatment of relapsing-remitting MS. In this trial, patients were randomly assigned to self-administer either 250µg interferon beta-1b subcutaneously every other day or 30µg interferon beta-1a intramuscularly once a week.

After two years, 51 per cent of patients on interferon beta-1b remained relapse-free compared with 36 per cent of patients on interferon beta-1a. The relative risk of relapse in the interferon beta-1b group compared with the beta-1a group was 0.76 (95 per cent confidence interval, 0.59–0.99, P=0.03). In addition, the proportion of patients with sustained disability progression after two years was lower in the interferon beta-1b group.

The researchers also assessed the efficacy of the two treatments using magnetic resonance imaging (MRI) in 149 patients. More patients on interferon beta-1b were free from new lesions than patients who received interferon beta-1a. The difference in efficacy between the two treatments increased over time.

The researchers comment that once-weekly administration of beta interferon offers benefits in terms of perceived convenience and reduced overall burden of adverse events compared with more frequent administration. However, they conclude that high-dose interferon beta-1b given on alternate days is more effective than interferon beta-1a given weekly. They add that a further study is needed to compare the treatments when they are both frequently administered (Lancet 2002;359: 1453).

Risk of diabetes In a second study published in The Lancet (2002;359:1461), risk of diabetes is shown to be linked with MS. The prevalence of type 1 diabetes was assessed in 1,090 people with MS and in their parents and siblings (over 5,000 people). Diabetes was found to occur three times more frequently in people with MS than in their healthy siblings and five times more frequently than in the general population.

However, the results might not apply to all MS patients. The study was conducted in Sardinia where susceptibility to MS is associated with a genotype different from that seen in patients of northern-European descent. In northern-Europeans, the genotype for MS appears to protect against type 1 diabetes.