By Harvey McConnell
A DGReview of :"Every-other-day
interferon beta-1b versus once-weekly interferon beta-1a for multiple sclerosis:
results of a 2-year prospective randomised multicentre study"
Lancet 2002; 359: 1453-60.
High-dose interferon beta-1b administered every other day is more effective than interferon beta-1a once a week for people with multiple sclerosis (MS), a two year multicenter study has found.
Dr Luca Durelli and colleagues at the Turin University Medical School, Turin, Italy, undertook this study in collaboration with colleagues at 15 other institutions in Italy. Until now, there has been no published research which directly compares the different regimens of interferon beta therapies.
The clinicians explain that efficacy of three different beta interferon products has been proved in multicenter controlled trials for the treatment of relapsing-remitting MS. Recombinant beta interferons are produced in different cell systems, which results in some differences in their amino acid structure, molecular weight, degree of glycosylation, and specific activity, and which are tested against the antiviral activity of the World Health Organization's reference standard of human interferon beta.
Each drug is registered for use at different doses and different administration: interferon beta-1a 30 mcg administered intramuscularly once a week; interferon beta-1a 22 mcg or 44 mcg given subcutaneously three times a week; and interferon beta-1b 250 mcg administered subcutaneously on alternate days.
In the prospective study, 188 patients with relapsing-remitting MS were randomised to receive either interferon beta-1b (96 patients) or interferon beta-1a (92 patients). Over two years, the researchers found that 51 percent of patients administered interferon beta-1b remained relapse-free compared with 36 percent of patients given interferon beta-1a.
In addition, 55 percent of the patients in the interferon beta-1b group, and 26 percent in the interferon beta-1a group remained free from new proton density/T2 brain lesions at MRI assessment.
Clinical and magnetic resonance imaging (MRI) benefits became more pronounced over time for patients treated with every-other-day interferon beta-1b compared with those treated with once-weekly interferon beta-1a.
"The probability of remaining relapse-free as well as that of remaining free from new proton density/T2 lesions for interferon beta-1b-treated patients compared with those treated with interferon beta-1a were greater during the second than during the first year of the trial. Such an increasing benefit over time underlines the importance of doing studies of sufficient duration."
They conclude that findings from their trial should be considered both
by treating neurologists and their patients who are considering starting
disease-modifying therapies for relapsing-remitting MS.
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