Neutralising antibodies to interferon beta during the treatment of multiple sclerosis

atients with multiple sclerosis (MS) receiving interferon beta may develop neutralising anti-interferon beta antibodies (NABs) during treatment. These NABs are clinically relevant and reduce the clinical efficacy of interferon beta. Although there is lack of consensus on how these antibodies should be measured, the relative prevalence of NABs induced by different interferon beta products seems to be consistent between studies. Subcutaneous interferon beta-1b (Betaferon) is the most immunogenic, followed by subcutaneous interferon beta-1a (Rebif), with intramuscular interferon beta-1a (Avonex) being the least immunogenic. Differences between the interferon beta products with regard to their structure/ biochemistry, formulation, dose, route of administration, and dose frequency are likely to contribute to these observed differences in immunogenicity. This editorial highlights the consequences of NABs formation on the biological and clinical activity of interferon beta and the implications NABs have for the practicing neurologist and patient with MS.